WorldWideScience

Sample records for high-dose three-dimensional conformal

  1. SU-E-T-279: Realization of Three-Dimensional Conformal Dose Planning in Prostate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z; Jiang, S; Yang, Z [Tianjin University, Tianjin (China); Bai, H; Zhang, X [Seeds biological Pharmacy Ltd, Tianjin (China)

    2014-06-01

    Purpose: Successful clinical treatment in prostate brachytherapy is largely dependent on the effectiveness of pre-surgery dose planning. Conventional dose planning method could hardly arrive at a satisfy result. In this abstract, a three-dimensional conformal localized dose planning method is put forward to ensure the accuracy and effectiveness of pre-implantation dose planning. Methods: Using Monte Carlo method, the pre-calculated 3-D dose map for single source is obtained. As for multiple seeds dose distribution, the maps are combined linearly to acquire the 3-D distribution. The 3-D dose distribution is exhibited in the form of isodose surface together with reconstructed 3-D organs group real-timely. Then it is possible to observe the dose exposure to target volume and normal tissues intuitively, thus achieving maximum dose irradiation to treatment target and minimum healthy tissues damage. In addition, the exfoliation display of different isodose surfaces can be realized applying multi-values contour extraction algorithm based on voxels. The needles could be displayed in the system by tracking the position of the implanted seeds in real time to conduct block research in optimizing insertion trajectory. Results: This study extends dose planning from two-dimensional to three-dimensional, realizing the three-dimensional conformal irradiation, which could eliminate the limitations of 2-D images and two-dimensional dose planning. A software platform is developed using VC++ and Visualization Toolkit (VTK) to perform dose planning. The 3-D model reconstruction time is within three seconds (on a Intel Core i5 PC). Block research could be conducted to avoid inaccurate insertion into sensitive organs or internal obstructions. Experiments on eight prostate cancer cases prove that this study could make the dose planning results more reasonable. Conclusion: The three-dimensional conformal dose planning method could improve the rationality of dose planning by safely reducing

  2. Doses to organs at cerebral risks: optimization by robotized stereotaxic radiotherapy and automatic segmentation atlas versus three dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Bondiau, P.Y.; Thariat, J.; Benezery, K.; Herault, J.; Dalmasso, C.; Marcie, S.; Malandain, G.

    2007-01-01

    The stereotaxic radiotherapy robotized by 'Cyberknife fourth generation' allows a dosimetric optimization with a high conformity index on the tumor and radiation doses limited on organs at risk. A cerebral automatic anatomic segmentation atlas of organs at risk are used in routine in three dimensions. This study evaluated the superiority of the stereotaxic radiotherapy in comparison with the three dimensional conformal radiotherapy on the preservation of organs at risk in regard of the delivered dose to tumors justifying an accelerated hypo fractionation and a dose escalation. This automatic segmentation atlas should allow to establish correlations between anatomy and cerebral dosimetry; This atlas allows to underline the dosimetry optimization by stereotaxic radiotherapy robotized for organs at risk. (N.C.)

  3. Intensity-modulated radiotherapy (IMRT) and conventional three-dimensional conformal radiotherapy for high-grade gliomas: Does IMRT increase the integral dose to normal brain?

    International Nuclear Information System (INIS)

    Hermanto, Ulrich; Frija, Erik K.; Lii, MingFwu J.; Chang, Eric L.; Mahajan, Anita; Woo, Shiao Y.

    2007-01-01

    Purpose: To determine whether intensity-modulated radiotherapy (IMRT) treatment increases the total integral dose of nontarget tissue relative to the conventional three-dimensional conformal radiotherapy (3D-CRT) technique for high-grade gliomas. Methods and Materials: Twenty patients treated with 3D-CRT for glioblastoma multiforme were selected for a comparative dosimetric evaluation with IMRT. Original target volumes, organs at risk (OAR), and dose-volume constraints were used for replanning with IMRT. Predicted isodose distributions, cumulative dose-volume histograms of target volumes and OAR, normal tissue integral dose, target coverage, dose conformity, and normal tissue sparing with 3D-CRT and IMRT planning were compared. Statistical analyses were performed to determine differences. Results: In all 20 patients, IMRT maintained equivalent target coverage, improved target conformity (conformity index [CI] 95% 1.52 vs. 1.38, p mean by 19.8% and D max by 10.7%), optic chiasm (D mean by 25.3% and D max by 22.6%), right optic nerve (D mean by 37.3% and D max by 28.5%), and left optic nerve (D mean by 40.6% and D max by 36.7%), p ≤ 0.01. This was achieved without increasing the total nontarget integral dose by greater than 0.5%. Overall, total integral dose was reduced by 7-10% with IMRT, p < 0.001, without significantly increasing the 0.5-5 Gy low-dose volume. Conclusions: These results indicate that IMRT treatment for high-grade gliomas allows for improved target conformity, better critical tissue sparing, and importantly does so without increasing integral dose and the volume of normal tissue exposed to low doses of radiation

  4. Comparison of normal tissue dose with three-dimensional conformal techniques for breast cancer irradiation including the internal mammary nodes

    NARCIS (Netherlands)

    van der Laan, Hans Paul; Dolsma, Willemtje; van t Veld, Aart; Bijl, HP; Langendijk, JA

    2005-01-01

    PURPOSE: To compare the Para Mixed technique for irradiation of the internal mammary nodes (IMN) with three commonly used strategies, by analyzing the dose to the heart and other organs at risk. METHODS AND MATERIALS: Four different three-dimensional conformal dose plans were created for 30 breast

  5. Dose response study of PVA-Fx gel for three dimensional dose distribution

    International Nuclear Information System (INIS)

    Brindha, S.; Ayyangar, Komanduri M.; Shen, Bin; Saw, Cheng B.

    2001-01-01

    Modern radiotherapy techniques involve complex field arrangements using conformal and intensity modulated radiation that requires three dimensional treatment planning. The verification of these plans poses even more challenge. In 1984, Gore et al., proposed that ferrous gel dosimeters combined with magnetic resonance imaging (MRI) could be used to measure three dimensional radiation dose distributions. Since then, there has been much interest in the development of gel dosimetry to aid the determination of three dimensional dose distributions during field arrangements. In this work, preparation and study of the MR characteristics of a PVA-Fx gel reported in the literature is presented

  6. Dosimetric comparison of three-dimensional conformal and intensity modulated radiotherapy in brain glioma

    International Nuclear Information System (INIS)

    Lu Jie; Zhang Guifang; Bai Tong; Yin Yong; Fan Tingyong; Wu Chaoxia

    2009-01-01

    Objective: To investigate the dosimetry advantages of intensity modulated radiotherapy (IMRT)of brain glioma compared with that of three-dimensional conformal radiotherapy (SD CRT). Methods: Ten patients with brain glioma were enrolled in this study. Three-dimensional conf0rmal and intensity modulated radiotherapy plans were performed for each patient. The dose distributions of target volume and normal tissues, conformal index (CI) and heterogeneous index (HI) were analyzed using the dose-volume histogram (DVH). The prescription dose was 60 Gy in 30 fractions. Results: IMRT plans decrease the maximum dose and volume of brainstem, mean dose of affected side parotid and maximum dose of spinal-cord. The CI for PTV of IMRT was superior to that of SD CRT, the HI for PTV has no statistical significance of the two model plans. Conclusions: IMRT plans can obviously decrease the dose and volume of brainstem. IMRT is a potential method in the treatment of brain glioma, and dose escalation was possible in patients with brain glioma. (authors)

  7. Three-dimensional conformal pancreas treatment: comparison of four- to six-field techniques

    International Nuclear Information System (INIS)

    Higgins, Patrick D.; Sohn, Jason W.; Fine, Robert M.; Schell, Michael C.

    1995-01-01

    Purpose: We compare practical conformal treatment approaches to pancreatic cancer using 6 and 18 MV photons and contrast those approaches against standard techniques. Methods and Materials: A four-field conformal technique for treating pancreas cancer has been developed using nonopposed 18 MV photons. This approach has been extended to 6 MV photon application by the addition of one to two fields. These techniques have been optimized to increase sparing of normal liver and bowel, compared with opposed-field methods, to improve patient tolerance of high doses. In this study we compare these techniques in a simulated tumor model in a cylindrical phantom. Dose-volume analysis is used to quantify differences between the conformal, nonopposed techniques with conformal, opposed field methods. This model is also used to evaluate the effect of 1-2 cm setup errors on dose-volume coverage. Results: Dose-volume analysis demonstrates that five-to-six field conformal treatments using 6 MV photons provides similar or better dose coverage and normal tissue sparing characteristics as an optimized 18 MV, four-field approach when 1-2 cm margins are included for setup uncertainty. All approaches using nonopposed beam geometry provide significant reduction in the volume of tissue encompassed by the 30-50% isodose surfaces, as compared with four-field box techniques. Conclusions: Three-dimensional (3D) conformal treatments can be designed that significantly improve dose-volume characteristics over conventional treatment designs without costing unacceptable amounts of machine time. Further, deep intraabdominal sites can be adequately accessed and treated on intermediate energy machines with a relatively moderate increase in machine time

  8. Pelvic Ewing sarcomas. Three-dimensional conformal vs. intensity-modulated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Mounessi, F.S.; Lehrich, P.; Haverkamp, U.; Eich, H.T. [Muenster Univ. (Germany). Dept. of Radiation Oncology; Willich, N. [Muenster Univ. (Germany). Dept. of Radiation Oncology; Universitaetsklinikum Muenster (Germany). RiSK - Registry for the Evaluation of Late Side Effects after Radiotherapy in Childhood and Adolescence; Boelling, T. [Center for Radiation Oncology, Osnabrueck (Germany)

    2013-04-15

    The goal of the present work was to assess the potential advantage of intensity-modulated radiotherapy (IMRT) over three-dimensional conformal radiotherapy (3D-CRT) planning in pelvic Ewing's sarcoma. A total of 8 patients with Ewing sarcoma of the pelvis undergoing radiotherapy were analyzed. Plans for 3D-CRT and IMRT were calculated for each patient. Dose coverage of the planning target volume (PTV), conformity and homogeneity indices, as well as further parameters were evaluated. Results The average dose coverage values for PTV were comparable in 3D-CRT and IMRT plans. Both techniques had a PTV coverage of V{sub 95} > 98 % in all patients. Whereas the IMRT plans achieved a higher conformity index compared to the 3D-CRT plans (conformity index 0.79 {+-} 0.12 vs. 0.54 {+-} 0.19, p = 0.012), the dose distribution across the target volumes was less homogeneous with IMRT planning than with 3D-CRT planning. This difference was statistically significant (homogeneity index 0.11 {+-} 0.03 vs. 0.07 {+-} 0.0, p = 0.035). For the bowel, D{sub mean} and D{sub 1%}, as well as V{sub 2} to V{sub 60} were reduced in IMRT plans. For the bladder and the rectum, there was no significant difference in D{sub mean}. However, the percentages of volumes receiving at least doses of 30, 40, 45, and 50 Gy (V{sub 30} to V{sub 50}) were lower for the rectum in IMRT plans. The volume of normal tissue receiving at least 2 Gy (V{sub 2}) was significantly higher in IMRT plans compared with 3D-CRT, whereas at high dose levels (V{sub 30}) it was significantly lower. Compared to 3D-CRT, IMRT showed significantly better results regarding dose conformity (p = 0.012) and bowel sparing at dose levels above 30 Gy (p = 0.012). Thus, dose escalation in the radiotherapy of pelvic Ewing's sarcoma can be more easily achieved using IMRT. (orig.)

  9. Dose Escalation for Prostate Cancer Using the Three-Dimensional Conformal Dynamic Arc Technique: Analysis of 542 Consecutive Patients

    International Nuclear Information System (INIS)

    Jereczek-Fossa, Barbara A.; Vavassori, Andrea; Fodor, Cristiana; Santoro, Luigi; Zerini, Dario; Cattani, Federica; Garibaldi, Cristina; Cambria, Raffaella; Fodor, Andrei; Boboc, Genoveva Ionela; Vitolo, Viviana; Ivaldi, Giovanni Battista; Musi, Gennaro; De Cobelli, Ottavio; Orecchia, Roberto

    2008-01-01

    Purpose: To present the results of dose escalation using three-dimensional conformal dynamic arc radiotherapy (3D-ART) for prostate cancer. Methods and Materials: Five hundred and forty two T1-T3N0M0 prostate cancer patients were treated with 3D-ART. Dose escalation (from 76 Gy/38 fractions to 80 Gy/40 fractions) was introduced in September 2003; 32% of patients received 80 Gy. In 366 patients, androgen deprivation was added to 3D-ART. Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria and Houston definition (nadir + 2) were used for toxicity and biochemical failure evaluation, respectively. Median follow-up was 25 months. Results: Acute toxicity included rectal (G1-2 28.9%; G3 0.5%) and urinary events (G1-2 57.9%; G3-4 2.4%). Late toxicity included rectal (G1-2 15.8%; G3-4 3.1%) and urinary events (G1-2 26.9%; G3-4 1.6%). Two-year failure-free survival and overall survival rates were 94.1% and 97.9%, respectively. Poor prognostic group (GS, iPSA, T), transurethral prostate resection, and dose >76 Gy showed significant association to high risk of progression in multivariate analysis (p = 0.014, p = 0.045, and p 0.04, respectively). The negative effect of dose >76 Gy was not observed (p 0.10), when the analysis was limited to 353 patients treated after September 2003 (when dose escalation was introduced). Higher dose was not associated with higher late toxicity. Conclusions: Three-dimensional-ART is a feasible modality allowing for dose escalation (no increase in toxicity has been observed with higher doses). However, the dose increase from 76 to 80 Gy was not associated with better tumor outcome. Further investigation is warranted for better understanding of the dose effect for prostate cancer

  10. Auto-optimisation for three-dimensional conformal radiotherapy of nasopharyngeal carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Wu, V.W.C. E-mail: orvinwu@polyu.edu.hk; Kwong, D.W.L.; Sham, J.S.T.; Mui, A.W.L

    2003-08-01

    Purpose: The purpose of this study was to evaluate the application of auto-optimisation in the treatment planning of three-dimensional conformal radiotherapy (3DCRT) of nasopharyngeal carcinoma (NPC). Methods: Twenty-nine NPC patients were planned by both forward planning and auto-optimisation methods. The forward plans, which consisted of three coplanar facial fields, were produced according to the routine planning criteria. The auto-optimised plans, which consisted of 5-15 (median 9) fields, were generated by the planning system after prescribing the dose requirements and the importance weightings of the planning target volume and organs at risk. Plans produced by the two planning methods were compared by the dose volume histogram, tumour control probability (TCP), conformity index and normal tissue complication probability (NTCP). Results: The auto-optimised plans reduced the average planner's time by over 35 min. It demonstrated better TCP and conformity index than the forward plans (P=0.03 and 0.04, respectively). Besides, the parotid gland and temporo-mandibular (TM) joint were better spared with the mean dose reduction of 31.8 and 17.7%, respectively. The slight trade off was the mild dose increase in spinal cord and brain stem with their maximum doses remaining within the tolerance limits. Conclusions: The findings demonstrated the potentials of auto-optimisation for improving target dose and parotid sparing in the 3DCRT of NPC with saving of the planner's time.

  11. Auto-optimisation for three-dimensional conformal radiotherapy of nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Wu, V.W.C.; Kwong, D.W.L.; Sham, J.S.T.; Mui, A.W.L.

    2003-01-01

    Purpose: The purpose of this study was to evaluate the application of auto-optimisation in the treatment planning of three-dimensional conformal radiotherapy (3DCRT) of nasopharyngeal carcinoma (NPC). Methods: Twenty-nine NPC patients were planned by both forward planning and auto-optimisation methods. The forward plans, which consisted of three coplanar facial fields, were produced according to the routine planning criteria. The auto-optimised plans, which consisted of 5-15 (median 9) fields, were generated by the planning system after prescribing the dose requirements and the importance weightings of the planning target volume and organs at risk. Plans produced by the two planning methods were compared by the dose volume histogram, tumour control probability (TCP), conformity index and normal tissue complication probability (NTCP). Results: The auto-optimised plans reduced the average planner's time by over 35 min. It demonstrated better TCP and conformity index than the forward plans (P=0.03 and 0.04, respectively). Besides, the parotid gland and temporo-mandibular (TM) joint were better spared with the mean dose reduction of 31.8 and 17.7%, respectively. The slight trade off was the mild dose increase in spinal cord and brain stem with their maximum doses remaining within the tolerance limits. Conclusions: The findings demonstrated the potentials of auto-optimisation for improving target dose and parotid sparing in the 3DCRT of NPC with saving of the planner's time

  12. Three-dimensional conformal radiation therapy: the tomo-therapy approach

    International Nuclear Information System (INIS)

    Linthout, N.; Verellen, D.; Coninck, P. de; Bel, A.; Storme, G.

    2000-01-01

    Conformal radiation therapy allows the possibility of delivering high doses at the tumor volume whilst limiting the dose to the surrounding tissues and diminishing the secondary effects. With the example of the conformal radiation therapy used at the AZ VU8 (3DCRT and tomo-therapy), two treatment plans of a left ethmoid carcinoma will be evaluated and discussed in detail. The treatment of ethmoid cancer is technically difficult for both radiation therapy and surgery because of the anatomic constraints and patterns of local spread. A radiation therapy is scheduled to be delivered after surgical resection of the tumor. The treatment plan for the radiation therapy was calculated on a three-dimensional (3D) treatment planning system based on virtual simulation with a beam's eye view: George Sherouse's Gratis. An effort was made to make the plan as conformal and as homogeneous as possible to deliver a dose of 66 Gy in 33 fractions at the tumor bed with a maximum dose of 56 Gy to the right optic nerve and the chiasma. To establish the clinical utility and potential advantages of tomo-therapy over 3DCRT for ethmoid carcinoma, the treatment of this patient was also planned with Peacock Plant. For both treatment plans the isodose distributions and cumulative dose volume histograms (CDVH) were computed. Superimposing the CDVHs yielded similar curves for the target and an obvious improvement for organs at risk such as the chiasma, brainstem and the left eye when applying tomo-therapy. These results have also been reflected in the tumor control probabilities (equal for both plans) and the normal tissue complication probabilities (NTCP), yielding significant reductions in NTCP for tomo-therapy. The probability of uncomplicated tumor control was 52.7% for tomo-therapy against 38.3% for 3DCRT. (authors)

  13. Implementation of three dimensional conformal radiation therapy: prospects, opportunities, and challenges

    International Nuclear Information System (INIS)

    Vijayakumar, Srinivasan; Chen, George T.Y.

    1995-01-01

    target volume(s), and planning target volume(s). Such definitions should make implementation of 3DCRT more complex, yet will make high-dose delivery a possibility. There are many sites in which single and multiinstitutional studies are ongoing that include prostate, lung, head and neck, and brain. In other areas, cooperative group trials are required because of the inability of single institutions to accrue enough patients to answer clinically relevant questions with statistical validity. Although implementation of 3DCRT will require multiple steps, these multiple steps can be brought into clinical practice gradually and one does not have to wait until all steps required for implementation of 3DCRT are available. In this respect, '3DCRT' should be used in a very broad sense, from beam's eye view blocking, use of multibeam dose distribution, use of dose-volume histograms in choosing alternative plans, noncoplanar beam arrangements, intensity modulation, inverse planning, to totally automated implementation of 3DCRT. To transfer the 3DCRT capabilities to the community from the University Centers, there is a necessity to develop quality assurance programs. RTOG and the Three-Dimensional Oncology Group are spearheading these efforts. Three-dimensional conformal radiation therapy has potential not only to improve local control and decrease toxicity, but also to improve the cost benefit ratio in the use of radiotherapy as well as in improving quality of life in patients with cancer. Conclusions: Achieving many potential benefits of 3DCRT (improvement in local control, decreasing toxicity, organs-function preservation, improvement in cost effectiveness) will require further physics-related and clinical research in carefully conceived and successfully completed future clinical trials

  14. Three dimensional conformal radiation therapy may improve the therapeutic ratio of radiation therapy after pneumonectomy for lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Trouette, R; Causse, N; Elkhadri, M; Caudry, M; Maire, J P; Houlard, J P; Racaldini, L; Demeaux, H

    1995-12-01

    Three dimensional conformal radiation therapy would allow to decrease the normal tissue dose while maintaining the same target dose as standard treatment. To evaluate the feasibility of normal tissue dose reduction for ten patients with pneumonectomy for lung cancer, we determined the dose distribution to the normal tissue with 3-dimensional conformal radiation therapy (3-DCRT) and conventional treatment planning (CTP). Dose-volume histograms for target and normal tissue (lung, heart) were used for comparison of the different treatment planning. The mean percentages of lung and heart volumes which received 40 Gy with 3-DCRT were respectively 63% and 37% of the mean percentage of lung and volumes which received the same dose with CTP. These preliminary results suggest that conformal therapy may improve the therapeutic ratio by reducing risk to normal tissue.

  15. Accelerated partial breast irradiation using robotic radiotherapy: a dosimetric comparison with tomotherapy and three-dimensional conformal radiotherapy.

    Science.gov (United States)

    Rault, Erwann; Lacornerie, Thomas; Dang, Hong-Phuong; Crop, Frederik; Lartigau, Eric; Reynaert, Nick; Pasquier, David

    2016-02-27

    Accelerated partial breast irradiation (APBI) is a new breast treatment modality aiming to reduce treatment time using hypo fractionation. Compared to conventional whole breast irradiation that takes 5 to 6 weeks, APBI is reported to induce worse cosmetic outcomes both when using three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). These late normal tissue effects may be attributed to the dose volume effect because a large portion of the non-target breast tissue volume (NTBTV) receives a high dose. In the context of APBI, non-coplanar beams could spare the NTBTV more efficiently. This study evaluates the dosimetric benefit of using the Cyberknife (CK) for APBI in comparison to IMRT (Tomotherapy) and three dimensional conformal radiotherapy (3D-CRT). The possibility of using surgical clips, implanted during surgery, to track target movements is investigated first. A phantom of a female thorax was designed in-house using the measurements of 20 patients. Surgical clips of different sizes were inserted inside the breast. A treatment plan was delivered to the mobile and immobile phantom. The motion compensation accuracy was evaluated using three radiochromic films inserted inside the breast. Three dimensional conformal radiotherapy (3D-CRT), Tomotherapy (TOMO) and CK treatment plans were calculated for 10 consecutive patients who received APBI in Lille. To ensure a fair comparison of the three techniques, margins applied to the CTV were set to 10 mm. However, a second CK plan was prepared using 3 mm margins to evaluate the benefits of motion compensation. Only the larger clips (VITALITEC Medium-Large) could be tracked inside the larger breast (all gamma indices below 1 for 1 % of the maximum dose and 1 mm). All techniques meet the guidelines defined in the NSABP/RTOG and SHARE protocols. As the applied dose volume constraints are very strong, insignificant dosimetric differences exist between techniques regarding the PTV

  16. Accelerated partial breast irradiation using robotic radiotherapy: a dosimetric comparison with tomotherapy and three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Rault, Erwann; Lacornerie, Thomas; Dang, Hong-Phuong; Crop, Frederik; Lartigau, Eric; Reynaert, Nick; Pasquier, David

    2016-01-01

    Accelerated partial breast irradiation (APBI) is a new breast treatment modality aiming to reduce treatment time using hypo fractionation. Compared to conventional whole breast irradiation that takes 5 to 6 weeks, APBI is reported to induce worse cosmetic outcomes both when using three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). These late normal tissue effects may be attributed to the dose volume effect because a large portion of the non-target breast tissue volume (NTBTV) receives a high dose. In the context of APBI, non-coplanar beams could spare the NTBTV more efficiently. This study evaluates the dosimetric benefit of using the Cyberknife (CK) for APBI in comparison to IMRT (Tomotherapy) and three dimensional conformal radiotherapy (3D-CRT). The possibility of using surgical clips, implanted during surgery, to track target movements is investigated first. A phantom of a female thorax was designed in-house using the measurements of 20 patients. Surgical clips of different sizes were inserted inside the breast. A treatment plan was delivered to the mobile and immobile phantom. The motion compensation accuracy was evaluated using three radiochromic films inserted inside the breast. Three dimensional conformal radiotherapy (3D-CRT), Tomotherapy (TOMO) and CK treatment plans were calculated for 10 consecutive patients who received APBI in Lille. To ensure a fair comparison of the three techniques, margins applied to the CTV were set to 10 mm. However, a second CK plan was prepared using 3 mm margins to evaluate the benefits of motion compensation. Only the larger clips (VITALITEC Medium-Large) could be tracked inside the larger breast (all gamma indices below 1 for 1 % of the maximum dose and 1 mm). All techniques meet the guidelines defined in the NSABP/RTOG and SHARE protocols. As the applied dose volume constraints are very strong, insignificant dosimetric differences exist between techniques regarding the PTV

  17. Analysis of Biochemical Control and Prognostic Factors in Patients Treated With Either Low-Dose Three-Dimensional Conformal Radiation Therapy or High-Dose Intensity-Modulated Radiotherapy for Localized Prostate Cancer

    International Nuclear Information System (INIS)

    Vora, Sujay A.; Wong, William W.; Schild, Steven E.; Ezzell, Gary A.; Halyard, Michele Y.

    2007-01-01

    Purpose: To identify prognostic factors and evaluate biochemical control rates for patients with localized prostate cancer treated with either high-dose intensity-modulated radiotherapy (IMRT) or conventional-dose three-dimensional conformal radiotherapy 3D-CRT. Methods: Four hundred sixteen patients with a minimum follow-up of 3 years (median, 5 years) were included. Two hundred seventy-one patients received 3D-CRT with a median dose of 68.4 Gy (range, 66-71 Gy). The next 145 patients received IMRT with a median dose of 75.6 Gy (range, 70.2-77.4 Gy). Biochemical control rates were calculated according to both American Society for Therapeutic Radiology and Oncology (ASTRO) consensus definitions. Prognostic factors were identified using both univariate and multivariate analyses. Results: The 5-year biochemical control rate was 60.4% for 3D-CRT and 74.1% for IMRT (p < 0.0001, first ASTRO Consensus definition). Using the ASTRO Phoenix definition, the 5-year biochemical control rate was 74.4% and 84.6% with 3D-RT and IMRT, respectively (p = 0.0326). Univariate analyses determined that PSA level, T stage, Gleason score, perineural invasion, and radiation dose were predictive of biochemical control. On multivariate analysis, dose, Gleason score, and perineural invasion remained significant. Conclusion: On the basis of both ASTRO definitions, dose, Gleason score, and perineural invasion were predictive of biochemical control. Intensity-modulated radiotherapy allowed delivery of higher doses of radiation with very low toxicity, resulting in improved biochemical control

  18. Estimate of the damage in organs induced by neutrons in three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Benites R, J. L.; Vega C, H. R.; Uribe, M. del R.

    2014-08-01

    By means of Monte Carlo methods was considered the damage in the organs, induced by neutrons, of patients with cancer that receive treatment in modality of three-dimensional conformal radiotherapy (3D-CRT) with lineal accelerator Varian Ix. The objective of this work was to estimate the damage probability in radiotherapy patients, starting from the effective dose by neutrons in the organs and tissues out of the treatment region. For that a three-dimensional mannequin of equivalent tissue of 30 x 100 x 30 cm 3 was modeled and spherical cells were distributed to estimate the Kerma in equivalent tissue and the absorbed dose by neutrons. With the absorbed dose the effective dose was calculated using the weighting factors for the organ type and radiation type. With the effective dose and the damage factors, considered in the ICRP 103, was considered the probability of damage induction in organs. (Author)

  19. Comparative dosimetric study of three-dimensional conformal, dynamic conformal arc, and intensity-modulated radiotherapy for brain tumor treatment using Novalis system

    International Nuclear Information System (INIS)

    Ding Meisong; Newman, Francis M.S.; Kavanagh, Brian D.; Stuhr, Kelly M.S.; Johnson, Tim K.; Gaspar, Laurie E.

    2006-01-01

    Purpose: To investigate the dosimetric differences among three-dimensional conformal radiotherapy (3D-CRT), dynamic conformal arc therapy (DCAT), and intensity-modulated radiotherapy (IMRT) for brain tumor treatment. Methods and Materials: Fifteen patients treated with Novalis were selected. We performed 3D-CRT, DCAT, and IMRT plans for all patients. The margin for the planning target volume (PTV) was 1 mm, and the specific prescription dose was 90% for all plans. The target coverage at the prescription dose, conformity index (CI), and heterogeneity index were analyzed for all plans. Results: For small tumors (PTV ≤2 cm 3 ), the three dosimetric parameters had approximate values for both 3D-CRT and DCAT plans. The CI for the IMRT plans was high. For medium tumors (PTV >2 to ≤100 cm 3 ), the three plans were competitive with each other. The IMRT plans had a greater CI, better target coverage at the prescription dose, and a better heterogeneity index. For large tumors (PTV >100 cm 3 ), the IMRT plan had good target coverage at the prescription dose and heterogeneity index and approximate CI values as those in the 3D-CRT and DCAT plans. Conclusion: The results of our study have shown that DCAT is suitable for most cases in the treatment of brain tumors. For a small target, 3D-CRT is useful, and IMRT is not recommended. For larger tumors, IMRT is superior to 3D-CRT and very competitive in sparing critical structures, especially for big tumors

  20. The therapeutic effect of three-dimensional conformal radiation therapy combined with conventional radiotherapy for nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Liang Feng; Lu Zhonghong; Yao Zhijun; Cao Yongzhen

    2011-01-01

    Objective: To observe the therapeutic effect of three-dimensional conformal radiation therapy (3DCRT) for nasopharyngeal carcinoma (NPC). Methods: 78 patients with NPC was treated by radiation schedule in two phases. In the first phase, nasopharyngeal lesions and metastases of all patients were treated by three-dimensional conformal radiation therapy (3DCRT) with a fraction of 2-5 Gy daily, 5 day per weeks, total dose 30 Gy. The second phase T1N0 or parts of T2N0 patients were done by Conventional radiotherapy with total dose 55 Gy on two small lateral opposing fields + with total dose 50 Gy on neck on tangential field,adding a 3 cm block. Patients with lymph node metastasis were given 55 Gy on the dacio-neck field (After 40 Gy, two small lateral opposing fields were used to boost the primary tumor while the spinal cord shielded) + with total dose 55 Gy on lower neck on tangential field. The upper bound of designed therapeutic field was set to connect with lower bound of main therapeutic field. Results: Three months after treatment,the rate of CR, PR, SD, PD were 38.5%, 55.1%, 5.1%, 1.3%, Total effective rate (CR+PR) were 93.6%. The 1-year, 2-year, 3-year and 5-year local-regional control rates were 92.3%, 88.5%, 78.2%, 70.5%.The 1-year, 2-year , 3-year and 5-year overall survival rate were 96.2%, 89.7%, 83.3%, 71.8%. Appearing early radiation response is well tolerated and no obviously mouth difficulties and cranial nerve damage observed. Conclusion: Clinical result of early-course three-dimensional conformal radiation therapy (3DCRT) for nasopharyngeal carcinoma (NPC) is good. (authors)

  1. Risk group dependence of dose-response for biopsy outcome after three-dimensional conformal radiation therapy of prostate cancer

    International Nuclear Information System (INIS)

    Levegruen, Sabine; Jackson, Andrew; Zelefsky, Michael J.; Venkatraman, Ennapadam S.; Skwarchuk, Mark W.; Schlegel, Wolfgang; Fuks, Zvi; Leibel, Steven A.; Ling, C. Clifton

    2002-01-01

    Background and purpose: We fit phenomenological tumor control probability (TCP) models to biopsy outcome after three-dimensional conformal radiation therapy (3D-CRT) of prostate cancer patients to quantify the local dose-response of prostate cancer. Materials and methods: We analyzed the outcome after photon beam 3D-CRT of 103 patients with stage T1c-T3 prostate cancer treated at Memorial Sloan-Kettering Cancer Center (MSKCC) (prescribed target doses between 64.8 and 81 Gy) who had a prostate biopsy performed ≥2.5 years after end of treatment. A univariate logistic regression model based on D mean (mean dose in the planning target volume of each patient) was fit to the whole data set and separately to subgroups characterized by low and high values of tumor-related prognostic factors T-stage ( 6), and pre-treatment prostate-specific antigen (PSA) (≤10 ng/ml vs. >10 ng/ml). In addition, we evaluated five different classifications of the patients into three risk groups, based on all possible combinations of two or three prognostic factors, and fit bivariate logistic regression models with D mean and the risk group category to all patients. Dose-response curves were characterized by TCD 50 , the dose to control 50% of the tumors, and γ 50 , the normalized slope of the dose-response curve at TCD 50 . Results: D mean correlates significantly with biopsy outcome in all patient subgroups and larger values of TCD 50 are observed for patients with unfavorable compared to favorable prognostic factors. For example, TCD 50 for high T-stage patients is 7 Gy higher than for low T-stage patients. For all evaluated risk group definitions, D mean and the risk group category are independent predictors of biopsy outcome in bivariate analysis. The fit values of TCD 50 show a clear separation of 9-10.6 Gy between low and high risk patients. The corresponding dose-response curves are steeper (γ 50 =3.4-5.2) than those obtained when all patients are analyzed together (γ 50 =2

  2. Results of three-dimensional conformal radiotherapy and thalidomide for advanced hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Hsu, Wei-Chung; Chung, Na-Na; Wang, Po-Ming; Ying, Kung-Shih; Shin, Jeng-Shiann; Chao, Che-Jen; Lin, Gau-De; Chan, Sue-Ching; Ting, Lai-Lei

    2006-01-01

    The purpose of this study was to evaluate the effectiveness of three-dimensional conformal radiotherapy and thalidomide in the treatment of advanced hepatocellular carcinoma. Between 1999 and 2003, 121 patients (mean age, 54.4±12.4 years; range, 20-81 years) with advanced hepatocellular carcinoma received three-dimensional conformal radiotherapy and thalidomide. Radiation was delivered in 1.5 Gy fractions twice daily for 5 days a week, for a total dose of 45-75 Gy. Mean treatment volume was 429.52±408.50 cm 3 (range, 26.89-2284.82 cm 3 ). Thalidomide was given concomitantly: 200 mg/day in 109 patients, 300 mg/day in 8 patients and 400 mg/day in 4 patients. Treatment responses, survival rates and factors affecting survival were analyzed. Treatment responses were observed in 61% of the patients. Liver cirrhosis (P=0.001) and tumor size (P=0.001) significantly affected the tumor responses. Overall survival at 6, 12 and 24 months was 84.8, 60.0 and 44.6%, respectively. On univariate analysis, liver cirrhosis (P=0.003), Karnofsky performance status (P=0.007), tumor size (P<0.001), portal vein tumor thrombosis (P<0.001) and alpha-fetoprotein level (P=0.003) were shown to significantly affect survival. On multivariate analysis, only thrombosis (P=0.039) and alpha-fetoprotein level (P=0.006) were shown to be factors affecting survival. Three-dimensional conformal radiotherapy with thalidomide seems to be effective in the treatment of advanced hepatocellular carcinoma. (author)

  3. Comparison of Heart and Coronary Artery Doses Associated With Intensity-Modulated Radiotherapy Versus Three-Dimensional Conformal Radiotherapy for Distal Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kole, Thomas P.; Aghayere, Osarhieme; Kwah, Jason [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Yorke, Ellen D. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Goodman, Karyn A., E-mail: goodmank@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2012-08-01

    Purpose: To compare heart and coronary artery radiation exposure using intensity-modulated radiotherapy (IMRT) vs. four-field three-dimensional conformal radiotherapy (3D-CRT) treatment plans for patients with distal esophageal cancer undergoing chemoradiation. Methods and Materials: Nineteen patients with distal esophageal cancers treated with IMRT from March 2007 to May 2008 were identified. All patients were treated to 50.4 Gy with five-field IMRT plans. Theoretical 3D-CRT plans with four-field beam arrangements were generated. Dose-volume histograms of the planning target volume, heart, right coronary artery, left coronary artery, and other critical normal tissues were compared between the IMRT and 3D-CRT plans, and selected parameters were statistically evaluated using the Wilcoxon rank-sum test. Results: Intensity-modulated radiotherapy treatment planning showed significant reduction (p < 0.05) in heart dose over 3D-CRT as assessed by average mean dose (22.9 vs. 28.2 Gy) and V30 (24.8% vs. 61.0%). There was also significant sparing of the right coronary artery (average mean dose, 23.8 Gy vs. 35.5 Gy), whereas the left coronary artery showed no significant improvement (mean dose, 11.2 Gy vs. 9.2 Gy), p = 0.11. There was no significant difference in percentage of total lung volume receiving at least 10, 15, or 20 Gy or in the mean lung dose between the planning methods. There were also no significant differences observed for the kidneys, liver, stomach, or spinal cord. Intensity-modulated radiotherapy achieved a significant improvement in target conformity as measured by the conformality index (ratio of total volume receiving 95% of prescription dose to planning target volume receiving 95% of prescription dose), with the mean conformality index reduced from 1.56 to 1.30 using IMRT. Conclusions: Treatment of patients with distal esophageal cancer using IMRT significantly decreases the exposure of the heart and right coronary artery when compared with 3D

  4. Toxicity and cosmetic outcome of three-dimensional conformal radiotherapy for accelerated partial breast irradiation

    International Nuclear Information System (INIS)

    Gatti, M.; Bresciani, S.; Ponzone, R.; Panaia, R.; Salatino, A.; Stasi, M.; Gabriele, P.

    2011-01-01

    Full text of publication follows: Purpose.- To analyse the incidence and severity of acute and late normal tissue toxicity and cosmetic outcome using three - dimensional conformal radiotherapy to deliver accelerated partial breast irradiation. Patients and Methods.- 70 patients with stage I disease were treated with three-dimensional conformal radiotherapy for accelerated partial breast irradiation, in an approved protocol. The prescribed dose was 34 Gy in all patients delivered in 10 fractions over 5 consecutive days. On all CT scans gross tumor volume (GTV ) was defined around surgical clips. A 1.5 cm margin was added in order to account for clinical target volume (CTV) . A margin of 1 cm was added to CTI to define the planning target volume (PTV). The dose-volume constraints were followed in accordance with the specifications as dictated in the NSABP/RTOG protocol. After treatment, patients underwent a clinical and cosmetic evaluation every 3 months. Late toxicity was evaluated according to the RTOG grading schema. The cosmetic assessment was performed by the physicians using the controlateral untreated breast as the reference (Harvard scale). Results.- Median patient age was 66 years (range 51-80). Median follow-up was 15 months (range 6-46). Tumor size was 2 cm in 4(6%). The mean value of the ratio between the PTV and the whole ipsilateral breast volume was 38 % and the median percentage whole breast volume that received 95 % of prescribed dose was 34% (range 16%-55%). The rate of G1 and G2 acute skin toxicity was 28% and 2% respectively and the late toxicity was 17% (G1). G2 or greater toxicities were not observed. The most pronounced G1 late toxicity was subcutaneous fibrosis, developed in 3 patients. The cosmetic outcome was excellent in 83% and good in 17%. Conclusion.- Accelerated partial breast irradiation using three-dimensional conformal radiotherapy is technically feasible with very low acute and late toxicity. Long-term results are needed to assess

  5. Three-Dimensional Non-Coplanar Conformal Radiotherapy Yields Better Results Than Traditional Beam Arrangements for Adjuvant Treatment of Gastric Cancer

    International Nuclear Information System (INIS)

    Soyfer, Viacheslav; Corn, Benjamin W.; Melamud, Alex B.S.; Alani, Shlomi; Tempelhof, Haim; Agai, Reuben; Shmueli, Anat; Figer, Arie; Kovner, Felix

    2007-01-01

    Purpose: The current standard of adjuvant treatment for gastric cancer after curative resection is concurrent administration of radiotherapy and 5-fluorouracil-based chemotherapy. The radiation fields are often arranged as anterioposterior-posteroanterior opposed parallel fields with general recommendations for sparing at least two-thirds of one kidney. We investigated whether a better radiation distribution would be achievable with three-dimensional conformal approaches compared with the classic anterioposterior-posteroanterior fields. Methods and Materials: A total of 19 patients with adenocarcinoma of the stomach were treated with adjuvant chemoradiotherapy using a non-coplanar four-field arrangement. In each case, parallel planning using an anterioposterior-posteroanterior arrangement and a four-field 'box' was performed, and the generated plans were subsequently compared for coverage of target volumes and doses to irradiated organs next to the tumor bed. A separate analysis was performed for kidneys exposed to greater and lower doses in each patient. The mean radiation dose and percentage of kidney volume receiving a dose >20 Gy were registered. Statistical analysis was performed using the two-tailed t test. Results: The clinical target volume was adequately covered in all three plans. In the greater-dose kidney group, all the differences were statistically significant with a benefit for the three-dimensional plan. In the lower-dose kidney group, the differences in the mean radiation dose did not reach the level of statistical significance, and the differences in the kidney volume receiving a dose >20 Gy showed a statistically significant benefit for the three-dimensional plan. Conclusion: Non-coplanar three-dimensional-based conformal planning for postoperative radiotherapy for gastric cancer provided the best results regarding kidney and spinal cord exposure with adequate clinical target volume coverage. This technique was readily implemented in clinical

  6. Three-dimensional non-coplanar conformal radiotherapy yields better results than traditional beam arrangements for adjuvant treatment of gastric cancer.

    Science.gov (United States)

    Soyfer, Viacheslav; Corn, Benjamin W; Melamud, Alex; Alani, Shlomi; Tempelhof, Haim; Agai, Reuben; Shmueli, Anat; Figer, Arie; Kovner, Felix

    2007-10-01

    The current standard of adjuvant treatment for gastric cancer after curative resection is concurrent administration of radiotherapy and 5-fluorouracil-based chemotherapy. The radiation fields are often arranged as anterioposterior-posteroanterior opposed parallel fields with general recommendations for sparing at least two-thirds of one kidney. We investigated whether a better radiation distribution would be achievable with three-dimensional conformal approaches compared with the classic anterioposterior-posteroanterior fields. A total of 19 patients with adenocarcinoma of the stomach were treated with adjuvant chemoradiotherapy using a non-coplanar four-field arrangement. In each case, parallel planning using an anterioposterior-posteroanterior arrangement and a four-field "box" was performed, and the generated plans were subsequently compared for coverage of target volumes and doses to irradiated organs next to the tumor bed. A separate analysis was performed for kidneys exposed to greater and lower doses in each patient. The mean radiation dose and percentage of kidney volume receiving a dose >20 Gy were registered. Statistical analysis was performed using the two-tailed t test. The clinical target volume was adequately covered in all three plans. In the greater-dose kidney group, all the differences were statistically significant with a benefit for the three-dimensional plan. In the lower-dose kidney group, the differences in the mean radiation dose did not reach the level of statistical significance, and the differences in the kidney volume receiving a dose >20 Gy showed a statistically significant benefit for the three-dimensional plan. Non-coplanar three-dimensional-based conformal planning for postoperative radiotherapy for gastric cancer provided the best results regarding kidney and spinal cord exposure with adequate clinical target volume coverage. This technique was readily implemented in clinical practice.

  7. Dose escalation of chart in non-small cell lung cancer: is three-dimensional conformal radiation therapy really necessary?

    International Nuclear Information System (INIS)

    McGibney, Carol; Holmberg, Ola; McClean, Brendan; Williams, Charles; McCrea, Pamela; Sutton, Phil; Armstrong, John

    1999-01-01

    Purpose: To evaluate, pre clinically, the potential for dose escalation of continuous, hyperfractionated, accelerated radiation therapy (CHART) for non small-cell lung cancer (NSCLC), we examined the strategy of omission of elective nodal irradiation with and without the application of three-dimensional conformal radiation technology (3DCRT). Methods and Materials: 2D, conventional therapy plans were designed according to the specifications of CHART for 18 patients with NSCLC (Stages Ib, IIb, IIIa, and IIIb). Further plans were generated with the omission of elective nodal irradiation (ENI) from the treatment portals (2D minus ENI plans [2D-ENI plans]). Both sets were inserted in the patient's planning computed tomographies (CTs). These reconstructed plans were then compared to alternative, three-dimensional treatment plans which had been generated de novo, with the omission of ENI: 3D minus elective nodal irradiation (3D-ENI plans). Dose delivery to the planning target volumes (PTVs) and to the organs at risk were compared between the 3 sets of corresponding plans. The potential for dose escalation of each patient's 2D-ENI and 3D-ENI plan beyond 54 Gy, standard to CHART, was also determined. Results: PTV coverage was suboptimal in the 2D CHART and the 2D-ENI plans. Only in the 3D-ENI plans did 100% of the PTV get ≥95% of the dose prescribed (i.e., 51.5 Gy [51.3-52.2]). Using 3D-ENI plans significantly reduced the dose received by the spinal cord, the mean and median doses to the esophagus and the heart. It did not significantly reduce the lung dose when compared to 2D-ENI plans. Escalation of the dose (minimum ≥1 Gy) with optimal PTV coverage was possible in 55.5% of patients using 3D-ENI, but was possible only in 16.6% when using the 2D-ENI planning strategy. Conclusions: 3DCRT is fundamental to achieving optimal PTV coverage in NSCLC. A policy of omission of elective nodal irradiation alone (and using 2D technology) will not achieve optimal PTV coverage or

  8. Dosimetric Comparison of Three Dimensional Conformal Radiation Radiotherapy and Helical Tomotherapy Partial Breast Cancer

    International Nuclear Information System (INIS)

    Kim, Dae Woong; Kim, Jong Won; Choi, Yun Kyeong; Kim, Jung Soo; Hwang, Jae Woong; Jeong, Kyeong Sik; Choi, Gye Suk

    2008-01-01

    The goal of radiation treatment is to deliver a prescribed radiation dose to the target volume accurately while minimizing dose to normal tissues. In this paper, we comparing the dose distribution between three dimensional conformal radiation radiotherapy (3D-CRT) and helical tomotherapy (TOMO) plan for partial breast cancer. Twenty patients were included in the study, and plans for two techniques were developed for each patient (left breast:10 patients, right breast:10 patients). For each patient 3D-CRT planning was using pinnacle planning system, inverse plan was made using Tomotherapy Hi-Art system and using the same targets and optimization goals. We comparing the Homogeneity index (HI), Conformity index (CI) and sparing of the organs at risk for dose-volume histogram. Whereas the HI, CI of TOMO was significantly better than the other, 3D-CRT was observed to have significantly poorer HI, CI. The percentage ipsilateral non-PTV breast volume that was delivered 50% of the prescribed dose was 3D-CRT (mean: 40.4%), TOMO (mean: 18.3%). The average ipsilateral lung volume percentage receiving 20% of the PD was 3D-CRT (mean: 4.8%), TOMO (mean: 14.2), concerning the average heart volume receiving 20% and 10% of the PD during treatment of left breast cancer 3D-CRT (mean: 1.6%, 3.0%), TOMO (mean: 9.7%, 26.3%) In summary, 3D-CRT and TOMO techniques were found to have acceptable PTV coverage in our study. However, in TOMO, high conformity to the PTV and effective breast tissue sparing was achieved at the expense of considerable dose exposure to the lung and heart.

  9. Conformal three dimensional radiotherapy treatment planning in Lund

    International Nuclear Information System (INIS)

    Knoos, T.; Nilsson, P.; Anders, A.

    1995-01-01

    The use of conformal therapy is based on 3-dimensional treatment planning as well as on methods and routines for 3-dimensional patient mapping, 3-dimensional virtual simulation and others. The management of patients at the Radiotherapy Department at the University Hospital in Lund (Sweden) is discussed. About 2100 new patients are annually treated with external radiotherapy using seven linear accelerators. Three of the accelerators have dual photon energies and electron treatment facilities. A multi-leaf collimator as well as an electronic portal imaging device are available on one machine. Two simulators and an in-house CT-scanner are used for treatment planning. From 1988 to 1992 Scandiplan (Umplan) was used. Since 1992, the treatment planning system is TMS (HELAX AB, Sweden), which is based on the pencil beam algorithm of Ahnesjo. The calculations use patient modulated accelerator specific energy fluence spectra which are compiled with pencil beams from Monte Carlo generated energy absorption kernels. Heterogeneity corrections are performed with results close to conventional algorithms. Irregular fields, either from standard or individual blocks and from multi-leaf collimators are handled by the treatment planning system. The field shape is determined conveniently using the beam's eye view. The final field shape is exported electronically to either the block cutting machine or the multileaf collimator control computer. All patient fields are checked against the beam's eye view during simulation using manual methods. Treatment verification is performed by portal films and in vivo dosimetry with silicon diodes or TL-dosimetry. Up to now, approximately 4400 patients have received a highly individualized 3-dimensional conformal treatment

  10. Dosimetric and clinical results of three-dimensional conformal radiotherapy for locally recurrent nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Zheng Xiaokang; Ma Jun; Chen Longhua; Xia Yunfei; Shi Yusheng

    2005-01-01

    Purpose: To assess the dosimetric and clinical results of three-dimensional conformal radiotherapy (3D CRT) for locally recurrent nasopharyngeal carcinoma (NPC). Methods: A total of 86 patients with locally recurrent NPC were retreated with 3D CRT. The median prescribed dose was 68 Gy with 2 Gy per fractionation. Dosimetric quality was evaluated with dose distribution in planning target volume (PTV) and specified organs at risk (OAR), dose conformity index (CI) and dose homogeneity index (HI). The actuarial rate of local failure-free (LFF), overall survival (OS) and major late toxicities (MLT) were estimated with Kaplan-Meier method. Multivariate analysis for prognosis was performed using the Cox regression proportional hazards model. Results: The mean dose to PTV averaged 66.8 Gy, and the dose to specified OAR was acceptable. The average value of CI and HI was 0.59 and 9.1%. The 5-year actuarial rate of LFF and OS was 71 and 40%, respectively. The 5-year actuarial incidence of MLT≥Grade 3 and ≥Grade 4 were 100 and 49%, respectively. The major prognostic factors were T stage and the size of gross tumor volume (GTV). Advanced T stage and large GTV volume were associated with poor LFF and OS and high risk of MLT. Conclusion: The dosimetric quality of 3D CRT for locally recurrent NPC is generally excellent. A relatively high local control was achieved with this technique. However, the incidence of late toxicities were not found to decrease as originally expected. Early diagnosis of the recurrence and reasonable definition of the target volume are crucial to achieve a better outcome

  11. Head and neck cancers: clinical benefits of three-dimensional conformal radiotherapy and of intensity-modulated radiotherapy

    International Nuclear Information System (INIS)

    Giraud, P.; Jaulerry, C.; Brunin, F.; Zefkili, S.; Helfre, S.; Chauvet, I.; Rosenwald, J.C.; Cosset, J.M.

    2002-01-01

    The conformal radiotherapy approach, three-dimensional conformal radiotherapy (3DCRT) or intensity-modulated radiotherapy (IMRT), is based on modern imaging modalities, efficient 3-D treatment planning systems, sophisticated immobilization systems and rigorous quality assurance and treatment verification. The central objective of conformal radiotherapy is to ensure a high dose distribution tailored to the limits of the target volume while reducing exposure of normal tissues. These techniques would then allow further tumor dose escalation. Head-and-neck tumors are some of the most attractive localizations to test conformal radiotherapy. They combine ballistic difficulties due to particularly complex shapes (nasopharynx, ethmoid) and problems due to the number and low tolerance of neighbouring organs like parotids, eyes, brainstem and spinal cord. The therapeutic irradiation of head-and-neck tumors thus remains a challenge for the radiation oncologist. Conformal radiotherapy does have a significant potential for improving local control and reducing toxicity when compared to standard radiotherapy. However, in the absence of prospective randomized trials, it is somewhat difficult at present to evaluate the real benefits drawn from 3DCRT and IMRT. The published clinical reports on the use of conformal radiotherapy are essentially dealing with dosimetric comparisons on relatively small numbers of patients. Recently, a few publications have emphasized the clinical experience several precursor teams with a suitable follow-up. This paper describes the current state-of-the-art of 3DCRT and IMRT in order to evaluate the impact of these techniques on head-and-neck cancers irradiation. (authors)

  12. Toxicity and cosmetic outcome of three-dimensional conformal radiotherapy for accelerated partial breast irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Gatti, M.; Bresciani, S.; Ponzone, R.; Panaia, R.; Salatino, A.; Stasi, M.; Gabriele, P. [IRCC, Candiolo (Italy)

    2011-10-15

    Full text of publication follows: Purpose.- To analyse the incidence and severity of acute and late normal tissue toxicity and cosmetic outcome using three - dimensional conformal radiotherapy to deliver accelerated partial breast irradiation. Patients and Methods.- 70 patients with stage I disease were treated with three-dimensional conformal radiotherapy for accelerated partial breast irradiation, in an approved protocol. The prescribed dose was 34 Gy in all patients delivered in 10 fractions over 5 consecutive days. On all CT scans gross tumor volume (GTV ) was defined around surgical clips. A 1.5 cm margin was added in order to account for clinical target volume (CTV) . A margin of 1 cm was added to CTI to define the planning target volume (PTV). The dose-volume constraints were followed in accordance with the specifications as dictated in the NSABP/RTOG protocol. After treatment, patients underwent a clinical and cosmetic evaluation every 3 months. Late toxicity was evaluated according to the RTOG grading schema. The cosmetic assessment was performed by the physicians using the controlateral untreated breast as the reference (Harvard scale). Results.- Median patient age was 66 years (range 51-80). Median follow-up was 15 months (range 6-46). Tumor size was < 10 mm in 33 patients (53%) and > 2 cm in 4(6%). The mean value of the ratio between the PTV and the whole ipsilateral breast volume was 38 % and the median percentage whole breast volume that received 95 % of prescribed dose was 34% (range 16%-55%). The rate of G1 and G2 acute skin toxicity was 28% and 2% respectively and the late toxicity was 17% (G1). G2 or greater toxicities were not observed. The most pronounced G1 late toxicity was subcutaneous fibrosis, developed in 3 patients. The cosmetic outcome was excellent in 83% and good in 17%. Conclusion.- Accelerated partial breast irradiation using three-dimensional conformal radiotherapy is technically feasible with very low acute and late toxicity. Long

  13. Therapeutic effect analysis of three dimensional conformal radiotherapy non-small cell lung cancer

    International Nuclear Information System (INIS)

    Yao Zhijun; Cao Yongzhen; Zhang Wenxue; Liang Feng

    2012-01-01

    Objective: To analyse the treatment effect of non-small cell lung cancer of three dimensional conformal radiotherapy (3D-CRT) and to study the effect of patient survival related factors. Methods: Retrospective analysis was mack for 136 cases of non-small cell lung cancer, all accept 3D-CRT, through the case data collection and long-term follow-up, using the single factor and multiple factor analysis survival time and its influencing factors. Results: The recent curative effects of 136 cases of patients with three dimensional conformal radiotherapy: Complete response (CR) 14.7% (20/136), partial response (PR) 60.3 (82/136), stable disease(SD) 19.9% (27/136), progression disease (PD) 5.1% (7/136), total effective rate is 75% (102/136). One, two, three, five year survival rate is 79.4%, 45.4%, 22.1%, 12.5%. Side effects: Class 1 radiated esophagitis 35 cases, Class 2 radiated esophagitis 16 cases, Class 3 and above radiated esophagitis 0 case. Class I radiated pneumonia 20 cases, Class 2 radiated pneumonia 9 cases, Class 3 radiated pneumonia 0 case. Single factor analysis shows the influence of gender, age, pathology, phase, dose, and first-phase curative effect to the survival time are of a statistical significance, Multiple factor analysis showed KPS score, phase, dose, first-phase curative effect are the survival time independent factors. Conclusion: 3D-CRT for patients with non-small cell lung carcinoma is a safe, effective treatment method, Side effects are relatively low, and the patients survival time is long after radiotherapy. (authors)

  14. Tolerance and early outcome results of postprostatectomy three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Zelefsky, Michael J.; Aschkenasy, Eric; Kelsen, Suzanne; Leibel, Steven A.

    1997-01-01

    Purpose: Three-dimensional conformal radiotherapy (3D-CRT) has been associated with a reduction in acute and late toxicity among patients treated for localized prostatic cancer. The purpose of this study is to assess the acute and late toxicity of 3D-CRT delivered to patients in the postprostatectomy setting and to analyze which factors predict for durable biochemical control in this group of patients. Methods and Materials: Between 1988 and 1994, 42 patients were treated after prostatectomy with three-dimensional conformal radiotherapy. The median time from prostatectomy to radiotherapy was 11 months. Indications for treatment included a rising serum PSA level in 28 patients (65%) and positive surgical margins without a rising PSA level in 14 (35%). Twenty-five patients (60%) had pathologic stage T3 disease, and 32 (74%) had tumor at or close to the surgical margins. The median dose was 64.8 Gy, and the median follow-up time was 2 years. Results: 3D-CRT in the postprostatectomy setting was well tolerated. Three patients (7%) experienced Grade II acute genitourinary toxicity and nine patients (21%) experienced Grade II acute gastrointestinal toxicity during treatment. No patient experienced Grade III or higher acute morbidity. The 2-year actuarial risk for Grade II late genitourinary and gastrointestinal late complications were 5 and 9%, respectively. In patients with existing incontinence, the incidence of worsening stress incontinence 6 months after treatment was 17%, which resolved within 12 months to its preradiotherapy level in four of six cases (66%). The overall 2-year postirradiation PSA relapse-free survival rate was 53%. The 2-year PSA relapse-free survival was 66% for patients with undetectable PSA levels in the immediate postoperative period compared to 26% for those with detectable levels of PSA after surgery (p 1.0 ng/ml (p 1 ng/ml (p < 0.002) was the most important covariate predicting for a rising PSA after radiotherapy. Conclusions: After

  15. Three-dimensional dose-response models of risk for radiation injury carcinogenesis

    International Nuclear Information System (INIS)

    Raabe, O.G.

    1988-01-01

    The use of computer graphics in conjunction with three-dimensional models of dose-response relationships for chronic exposure to ionizing radiation dramaticly clarifies the separate and interactive roles of competing risks. The three dimensions are average dose rate, exposure time, and risk. As an example, the functionally injurious and carcinogenic responses after systemic uptake of Ra-226 by beagles, mice and people with consequent alpha particle irradiation of the bone are represented by three-dimensional dose-rate/time/response surfaces that demonstrate the contributions with the passage of time of the competing deleterious responses. These relationships are further evaluated by mathematical stripping with three-dimensional illustrations that graphically show the resultant separate contribution of each effect. Radiation bone injury predominates at high dose rates and bone cancer at intermediate dose rates. Low dose rates result in spontaneous deaths from natural aging, yielding a type of practical threshold for bone cancer induction. Risk assessment is benefited by the insights that become apparent with these three-dimensional models. The improved conceptualization afforded by them contributes to planning and evaluating epidemiological analyses and experimental studies

  16. Sexual Function After Three-Dimensional Conformal Radiotherapy for Prostate Cancer: Results From a Dose-Escalation Trial

    International Nuclear Information System (INIS)

    Wielen, Gerard J. van der; Putten, Wim van; Incrocci, Luca

    2007-01-01

    Purpose: The purpose of this study is to provide information about sexual function (SF) after three-dimensional conformal radiotherapy (3D-CRT) for prostate cancer while taking important factors into account that influence SF. Methods and Materials: Between June 1997 and February 2003, a total of 268 patients from a randomized dose-escalation trial comparing 68 Gy and 78 Gy agreed to participate in an additional part of the trial that evaluated SF. Results: At baseline 28% of patients had erectile dysfunction (ED). After 1 year, 27% of the pretreatment potent patients had developed ED. After 2 years this percentage had increased to 36%. After 3 years it almost stabilized at 38%. Satisfaction with sexual life was significantly correlated with ED. After 2 years one third of the pre-treatment potent patients still had considerable to very much sexual desire and found sex (very) important. No significant differences were found between the two dose-arms. Potency aids were used on a regular base by 14% of the patients. Conclusion: By taking adjuvant hormonal therapy (HT), HT during follow-up and potency aids into account, we found a lower percentage of ED after 3D-CRT than reported in previous prospective studies. A large group of patients still had sexual desire, considered sex important and 14% used potency aids after 3D-CRT

  17. Conformal three dimensional radiotherapy treatment planning in Lund

    Energy Technology Data Exchange (ETDEWEB)

    Knoos, T; Nilsson, P [Lund Univ. (Sweden). Dept. of Radiation Physics; Anders, A [Lund Univ. (Sweden). Dept. of Oncology

    1995-12-01

    The use of conformal therapy is based on 3-dimensional treatment planning as well as on methods and routines for 3-dimensional patient mapping, 3-dimensional virtual simulation and others. The management of patients at the Radiotherapy Department at the University Hospital in Lund (Sweden) is discussed. About 2100 new patients are annually treated with external radiotherapy using seven linear accelerators. Three of the accelerators have dual photon energies and electron treatment facilities. A multi-leaf collimator as well as an electronic portal imaging device are available on one machine. Two simulators and an in-house CT-scanner are used for treatment planning. From 1988 to 1992 Scandiplan (Umplan) was used. Since 1992, the treatment planning system is TMS (HELAX AB, Sweden), which is based on the pencil beam algorithm of Ahnesjo. The calculations use patient modulated accelerator specific energy fluence spectra which are compiled with pencil beams from Monte Carlo generated energy absorption kernels. Heterogeneity corrections are performed with results close to conventional algorithms. Irregular fields, either from standard or individual blocks and from multi-leaf collimators are handled by the treatment planning system. The field shape is determined conveniently using the beam`s eye view. The final field shape is exported electronically to either the block cutting machine or the multileaf collimator control computer. All patient fields are checked against the beam`s eye view during simulation using manual methods. Treatment verification is performed by portal films and in vivo dosimetry with silicon diodes or TL-dosimetry. Up to now, approximately 4400 patients have received a highly individualized 3-dimensional conformal treatment.

  18. Initial dosimetric experience using simple three-dimensional conformal external-beam accelerated partial-breast irradiation

    International Nuclear Information System (INIS)

    Taghian, Alphonse G.; Kozak, Kevin R.; Doppke, Karen P.; Katz, Angela; Smith, Barbara L.; Gadd, Michele; Specht, Michelle; Hughes, Kevin; Braaten, Kristina; Kachnic, Lisa A.; Recht, Abram; Powell, Simon N.

    2006-01-01

    Purpose: Several accelerated partial-breast irradiation (APBI) techniques are being investigated in patients with early-stage breast cancer. We present our initial experience using three-dimensional conformal radiation therapy (3D-CRT). Methods and Materials: Sixty-one patients with tumors of 2 cm or less and negative axillary nodes were treated with 3D-CRT accelerated partial-breast irradiation (APBI) between August 2003 and March 2005. The prescribed radiation dose was 32 Gy in 4-Gy fractions given twice daily. Efforts were made to minimize the number of beams required to achieve adequate planning target volume (PTV) coverage. Results: A combination of photons and electrons was used in 85% of patients. A three-field technique that consisted of opposed, conformal tangential photons and enface electrons was employed in 43 patients (70%). Nine patients (15%) were treated with a four-field arrangement, which consisted of three photon fields and enface electrons. Mean PTV volumes that received 100%, 95%, and 90% of the prescribed dose were 93% ± 7%, 97% ± 4%, and 98% ± 2%, respectively. Dose inhomogeneity exceeded 10% in only 7 patients (11%). Mean doses to the ipsilateral lung and heart were 1.8 Gy and 0.8 Gy, respectively. Conclusions: Simple 3D-CRT techniques of APBI can achieve appropriate PTV coverage while offering significant normal-tissue sparing. Therefore, this noninvasive approach may increase the availability of APBI to patients with early-stage breast cancer

  19. FXG dosimeter response for three-dimensional conformal radiotherapy using different evaluation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Cavinato, Christianne C.; Campos, Leticia L., E-mail: ccavinato@ipen.b, E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Souza, Benedito H.; Carrete Junior, Henrique; Daros, Kellen A.C.; Medeiros, Regina B., E-mail: bhsouza@unifesp.b, E-mail: daros.kellen@unifesp.b, E-mail: rbitel-li.ddi@epm.b [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Dept. de Diagnostico por Imagem; Giordani, Adelmo J. [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Servico de Radioterapia

    2011-07-01

    This work aims to compare the dose-response of the Fricke xylenol gel (FXG) dosimeter developed at IPEN using 270 Bloom gelatin from porcine skin made in Brazil evaluated using the magnetic resonance imaging (MRI) technique with the dosimetric response evaluated using the optical absorption (OA) spectrophotometry technique, in order to verify the possibility of quality assurance (QA) and reproducibility of FXG dosimeter to be carried out routinely using the OA technique for three-dimensional conformal radiotherapy (3DCRT) application using a 6 MV photons linear accelerator. The response in function of the absorbed dose of FXG dosimeter developed at IPEN presents linear behavior in clinical interest dose range when irradiated with Co-60 gamma radiation and 6 MV photons and evaluated using the MRI and OA techniques. The results indicate that the optical technique can be used for QA of FXG dosemeter when used in the possible application in QA of 3DCRT. (author)

  20. FXG dosimeter response for three-dimensional conformal radiotherapy using different evaluation techniques

    International Nuclear Information System (INIS)

    Cavinato, Christianne C.; Campos, Leticia L.; Souza, Benedito H.; Carrete Junior, Henrique; Daros, Kellen A.C.; Medeiros, Regina B.; Giordani, Adelmo J.

    2011-01-01

    This work aims to compare the dose-response of the Fricke xylenol gel (FXG) dosimeter developed at IPEN using 270 Bloom gelatin from porcine skin made in Brazil evaluated using the magnetic resonance imaging (MRI) technique with the dosimetric response evaluated using the optical absorption (OA) spectrophotometry technique, in order to verify the possibility of quality assurance (QA) and reproducibility of FXG dosimeter to be carried out routinely using the OA technique for three-dimensional conformal radiotherapy (3DCRT) application using a 6 MV photons linear accelerator. The response in function of the absorbed dose of FXG dosimeter developed at IPEN presents linear behavior in clinical interest dose range when irradiated with Co-60 gamma radiation and 6 MV photons and evaluated using the MRI and OA techniques. The results indicate that the optical technique can be used for QA of FXG dosemeter when used in the possible application in QA of 3DCRT. (author)

  1. Phase I Study of Concurrent High-Dose Three-Dimensional Conformal Radiotherapy With Chemotherapy Using Cisplatin and Vinorelbine for Unresectable Stage III Non-Small-Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sekine, Ikuo, E-mail: isekine@ncc.go.jp [Division of Internal Medicine and Thoracic Oncology, National Cancer Center Hospital, Tokyo (Japan); Sumi, Minako; Ito, Yoshinori [Division of Radiation Oncology, National Cancer Center Hospital, Tokyo (Japan); Horinouchi, Hidehito; Nokihara, Hiroshi; Yamamoto, Noboru; Kunitoh, Hideo; Ohe, Yuichiro; Kubota, Kaoru; Tamura, Tomohide [Division of Internal Medicine and Thoracic Oncology, National Cancer Center Hospital, Tokyo (Japan)

    2012-02-01

    Purpose: To determine the maximum tolerated dose in concurrent three-dimensional conformal radiotherapy (3D-CRT) with chemotherapy for unresectable Stage III non-small-cell lung cancer (NSCLC). Patients and Methods: Eligible patients with unresectable Stage III NSCLC, age {>=}20 years, performance status 0-1, percent of volume of normal lung receiving 20 GY or more (V{sub 20}) {<=}30% received three to four cycles of cisplatin (80 mg/m{sup 2} Day 1) and vinorelbine (20 mg/m{sup 2} Days 1 and 8) repeated every 4 weeks. The doses of 3D-CRT were 66 Gy, 72 Gy, and 78 Gy at dose levels 1 to 3, respectively. Results: Of the 17, 16, and 24 patients assessed for eligibility, 13 (76%), 12 (75%), and 6 (25%) were enrolled at dose levels 1 to 3, respectively. The main reasons for exclusion were V{sub 20} >30% (n = 10) and overdose to the esophagus (n = 8) and brachial plexus (n = 2). There were 26 men and 5 women, with a median age of 60 years (range, 41-75). The full planned dose of radiotherapy could be administered to all the patients. Grade 3-4 neutropenia and febrile neutropenia were noted in 24 (77%) and 5 (16%) of the 31 patients, respectively. Grade 4 infection, Grade 3 esophagitis, and Grade 3 pulmonary toxicity were noted in 1 patient, 2 patients, and 1 patient, respectively. The dose-limiting toxicity was noted in 17% of the patients at each dose level. The median survival and 3-year and 4-year survival rates were 41.9 months, 72.3%, and 49.2%, respectively. Conclusions: 72 Gy was the maximum dose that could be achieved in most patients, given the predetermined normal tissue constraints.

  2. The value of 18F-FDG PET in three-dimensional conformal radiotherapy of cancer

    International Nuclear Information System (INIS)

    Lv Huiqing; Zhang Zhongmin; Lv Zhonghong

    2006-01-01

    Three-dimensional conformal radiotherapy (3D-CRT) is based on an extensive use of modern medical imaging techniques. Delineation of the gross tumor volume and organs at risk constitutes one of the most important phases of conformal radiotherapy procedures. 18 F-fluorodeoxyglucose ( 18 F-FDG) PET possesses greater sensitivity and accuracy in detecting diseased lymph nodes, is an important staging examination for patients considered for radiation treatment with curative intent. 18 F-FDG PET has an important role in delineation of gross tumor volume for patients treated with three-dimensional conformal radiotherapy. (authors)

  3. Integral Dose and Radiation-Induced Secondary Malignancies: Comparison between Stereotactic Body Radiation Therapy and Three-Dimensional Conformal Radiotherapy

    Directory of Open Access Journals (Sweden)

    Stefano G. Masciullo

    2012-11-01

    Full Text Available The aim of the present paper is to compare the integral dose received by non-tumor tissue (NTID in stereotactic body radiation therapy (SBRT with modified LINAC with that received by three-dimensional conformal radiotherapy (3D-CRT, estimating possible correlations between NTID and radiation-induced secondary malignancy risk. Eight patients with intrathoracic lesions were treated with SBRT, 23 Gy × 1 fraction. All patients were then replanned for 3D-CRT, maintaining the same target coverage and applying a dose scheme of 2 Gy × 32 fractions. The dose equivalence between the different treatment modalities was achieved assuming α/β = 10Gy for tumor tissue and imposing the same biological effective dose (BED on the target (BED = 76Gy10. Total NTIDs for both techniques was calculated considering α/β = 3Gy for healthy tissue. Excess absolute cancer risk (EAR was calculated for various organs using a mechanistic model that includes fractionation effects. A paired two-tailed Student t-test was performed to determine statistically significant differences between the data (p ≤ 0.05. Our study indicates that despite the fact that for all patients integral dose is higher for SBRT treatments than 3D-CRT (p = 0.002, secondary cancer risk associated to SBRT patients is significantly smaller than that calculated for 3D-CRT (p = 0.001. This suggests that integral dose is not a good estimator for quantifying cancer induction. Indeed, for the model and parameters used, hypofractionated radiotherapy has the potential for secondary cancer reduction. The development of reliable secondary cancer risk models seems to be a key issue in fractionated radiotherapy. Further assessments of integral doses received with 3D-CRT and other special techniques are also strongly encouraged.

  4. Three-dimensional conformal breast irradiation in the prone position

    Directory of Open Access Journals (Sweden)

    C. Kurtman

    2003-10-01

    Full Text Available The prone position can be used for the planning of adjuvant radiotherapy after conservative breast surgery in order to deliver less irradiation to lung and cardiac tissue. In the present study, we compared the results of three-dimensional conformal radiotherapy planning for five patients irradiated in the supine and prone position. Tumor stage was T1N0M0 in four patients and T1N1M0 in one. All patients had been previously submitted to conservative breast surgery. Breast size was large in three patients and moderate in the other two. Irradiation in the prone position was performed using an immobilization foam pad with a hole cut into it to accommodate the breast so that it would hang down away from the chest wall. Dose-volume histograms showed that mean irradiation doses reaching the ipsilateral lung were 8.3 ± 3.6 Gy with the patient in the supine position and 1.4 ± 1.0 Gy with the patient in the prone position (P = 0.043. The values for the contralateral lung were 1.3 ± 0.7 and 0.3 ± 0.1 Gy (P = 0.043 and the values for cardiac tissue were 4.6 ± 1.6 and 3.0 ± 1.7 Gy (P = 0.079, respectively. Thus, the dose-volume histograms demonstrated that lung tissue irradiation was significantly lower with the patient in the prone position than in the supine position. Large-breasted women appeared to benefit most from irradiation in the prone position. Prone position breast irradiation appears to be a simple and effective alternative to the conventional supine position for patients with large breasts, since they are subjected to lower pulmonary doses which may cause less pulmonary side effects in the future.

  5. High dose three-dimensional conformal boost (3DCB) using an orthogonal diagnostic X-ray set-up for patients with gynecological malignancy: a new application of real-time tumor-tracking system

    International Nuclear Information System (INIS)

    Yamamoto, Ritsu; Yonesaka, Akio; Nishioka, Seiko; Watari, Hidemichi; Hashimoto, Takayuki; Uchida, Daichi; Taguchi, Hiroshi; Nishioka, Takeshi; Miyasaka, Kazuo; Sakuragi, Noriaki; Shirato, Hiroki

    2004-01-01

    The feasibility and accuracy of high dose three-dimensional conformal boost (3DCB) using three internal fiducial markers and a two-orthogonal X-ray set-up of the real-time tumor-tracking system on patients with gynecological malignancy were investigated in 10 patients. The standard deviation of the distribution of systematic deviations (Σ) was reduced from 3.8, 4.6, and 4.9 mm in the manual set-up to 2.3, 2.3 and 2.7 mm in the set-up using the internal markers. The average standard deviation of the distribution of random deviations (σ) was reduced from 3.7, 5.0, and 4.5 mm in the manual set-up to 3.3, 3.0, and 4.2 mm in the marker set-up. The appropriate PTV margin was estimated to be 10.2, 12.8, and 12.9 mm in the manual set-up and 6.9, 6.7, and 8.3 mm in the gold marker set-up, respectively, using the formula 2Σ+0.7σ. Set-up of the patients with three markers and two fluoroscopy is useful to reduce PTV margin and perform 3DCB

  6. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT).

    Science.gov (United States)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-12-01

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147-53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose-volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques.

  7. A custom made phantom for dosimetric audit and quality assurance of three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Radaideh, K.M.; Matalqah, L.M.; Matalqah, L.M.; Tajuddin, A.A.; Luen, F.W.L.; Bauk, S.; Abdel Munem, E.M.E.

    2012-01-01

    The ultimate check of the actual dose delivered to a patient in radiotherapy can be achieved by using dosimetric measurements. The aims of this study were to develop and evaluate a custom handmade head and neck phantom for evaluation of Three-Dimensional Conformal Radiation Therapy (3D-CRT) dose planning and delivery. A phantom of head and neck region of a medium built male patient with nasopharyngeal cancer was constructed from Perspex material. Primary and secondary Planning Target Volume (PTV) and twelve Organs at Risk (OAR) were delineated using Treatment Planning System (TPS) guided by computed tomography printout transverse images. One hundred and seven (107) holes distributed among the organs were loaded with Rod-shaped Thermoluminescent dosimeters (LiF:Mg, Ti TLDs) after common and individual calibration. Head and neck phantom was imaged, planned and irradiated conformally (3D-CRT) by linear accelerator (LINAC Siemens Artiste). The planned predicted doses by TPS at PTV and OAR regions were obtained and compared with the TLD measured doses using the phantom. Repeated TLD measurements were reproducible with a percent standard deviation of < 3.5 %. Moreover, the average of dose discrepancies between TLDs reading and TPS predicted doses were found to be < 5.3 %. The phantom's preliminary results have proved to be a valuable tool for 3D-CRT treatment dose verification. (author)

  8. Treatment of primany hepatic carcinoma with three-dimensional conformal radiation therapy combined with transcatheter arterial chemoembolization

    International Nuclear Information System (INIS)

    Wu Li; Wen Xiaoping; Huang Wei

    2006-01-01

    Objective: To evaluate the effects of three-dimensional conformal radiation therapy (3DCRT) combined with transcatheter arterial chemoembolization (TACE) on stage m/IV primary hepatic carcinoma. Methods: Eighty cases of stage III/IV primary hepatic carcinoma were randomly divided into two groups: 40 cases treated with three-dimensional conformal radiation therapy combined with transcatheter arterial chemoembolization (3DCRT + TACE group) and 40 cases treated with three-dimensional conformal radiation therapy associated with hepatic arterial infusion chemotherapy (3DCRT +HAI group). Results: The response rates were 75% and 45% in 3DCRT + TACE group and 3DCRT + HAI group, respectively; and the difference between the two groups was statistically significant (P 0.05), The 0.5-, 1- and 2-year survival rates were 73% , 45% and 28% in 3DCRT + TACE group, and 45%, 25% and 13% in 3DCRT + HAI group, respectively; and the difference between the two groups was statistically significant (P 0.05). Conclusion: Three-dimensional conformal radiation therapy combined with transcatheter arterial chemoembolization improved prognosis of stage III/IV primary hepatic carcinoma. (authors)

  9. Lateral rectal shielding reduces late rectal morbidity after high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a dose effect

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W Robert; Hanks, Gerald E; Hanlon, Alexandra; Schultheiss, Timothy E

    1995-07-01

    Purpose: Using conventional treatment methods for the treatment of clinically localized prostate cancer central axis doses must be limited to 65-70 Gy to prevent significant damage to nearby normal tissues. A fundamental hypothesis of three-dimensional conformal radiation therapy (3DCRT) is that, by defining the target organ(s) accurately in three dimensions, it is possible to deliver higher doses to the target without a significant increase in normal tissue complications. This study examines whether this hypothesis holds true and whether a simple modification of treatment technique can reduce the incidence of late rectal morbidity in patients with prostate cancer treated with 3DCRT to minimum planning target volume (PTV) doses of 71-75 Gy. Materials and Methods: 257 patients with clinically localized prostate cancer completed 3DCRT by December 31, 1993 and received a minimum PTV dose of 71-75 Gy. The median follow-up time was 22 months (range 4-67 months) and 98% of patients had followup of longer than 12 months. The calculated dose at the center of the prostate was <74 Gy in 19 patients, 74-76 Gy in 206 patients and >76 Gy in 32 patients. Late rectal morbidity was graded according to the LENT scoring system. Eighty-eight consecutive patients were treated with a rectal block added to the lateral fields. In these patients the posterior margin from the prostate to the block edge was reduced from the standard 15 mm to 7.5 mm for the final 10 Gy which reduced the dose to portions of the anterior rectal wall by approximately 4-5 Gy. Estimates of rates for rectal morbidity were determined by Kaplan-Meier actuarial analyses. Differences in morbidity percentages were evaluated by the Pearson chi square test. Results: Grade 2-3 rectal morbidity developed in 46 of 257 patients (18%) and in the majority of cases consisted of rectal bleeding. No patient has developed grade 4 or 5 rectal morbidity. The actuarial rate of grade 2-3 morbidity is 22% at 24 months and the median

  10. Three-dimensional visualization and measurement of conformal dose distributions using magnetic resonance imaging of bang polymer gel dosimeters

    International Nuclear Information System (INIS)

    Ibbott, Geoffrey S.; Maryanski, Marek J.; Eastman, Peter; Holcomb, Stephen D.; Yashan, Zhang; Avison, Robin G.; Sanders, Michael; Gore, John C.

    1997-01-01

    nonlinear least-squares fit based on the Levenberg-Marquardt algorithm. The program also creates a dose-to-R2 calibration function by fitting a polynomial to a set of dose and R2 data points, obtained from gels irradiated in test tubes to known doses. This function can then be applied to any other R2 map, so that a dose map can be computed and displayed. Results: Through exposure to known doses of radiation, the gel has been shown to respond linearly with dose in the range of 0 to 10 Gy, and its response is independent of the beam energy or modality. Dose distributions have been imaged in orthogonal planes, and can be displayed in a convenient form for comparison with isodose plans. The response of the gel is stable; the gel can be irradiated at any time after its manufacture, and imaging can be conducted any time following a brief interval after irradiation. Conclusion: The polymer gel dosimeter has been shown to be a valuable device for displaying three-dimensional dose distributions. The imaged dose distribution can be compared easily with calculated dose distributions, to validate a treatment planning system. In the future, gels may be prepared in anthropomorphic phantoms, to confirm unique patient dose distributions

  11. Radiotherapy for Adult Medulloblastoma: Evaluation of Helical Tomotherapy, Volumetric Intensity Modulated Arc Therapy, and Three-Dimensional Conformal Radiotherapy and the Results of Helical Tomotherapy Therapy

    Directory of Open Access Journals (Sweden)

    Sun Zong-wen

    2018-01-01

    Full Text Available Introduction. All adult medulloblastoma (AMB patients should be treated with craniospinal irradiation (CSI postoperatively. Because of the long irradiation range, multiple radiation fields must be designed for conventional radiotherapy technology. CSI can be completed in only one session with helical tomotherapy (HT. We evaluated the dose of HT, volumetric intensity modulated arc therapy (VMAT, and three-dimensional conformal radiotherapy (3D-CRT of AMB and the results of 5 cases of AMB treated with HT. Methods. Complete craniospinal and posterior cranial fossa irradiation with HT, VMAT, and 3D-CRT and dose evaluation were performed. And results of 5 cases of AMB treated with HT were evaluated. Results. A large volume of tissue was exposed to low dose radiation in the organs at risk (OAR, while a small volume was exposed to high dose radiation with HT. The conformity and uniformity of the targets were good with HT and VMAT, and the volume of targets exposed to high dose with VMAT was larger than that of HT. The uniformity of 3D-CRT was also good, but the dose conformity was poor. The main toxicity was hematologic toxicity, without 4th-degree bone marrow suppression. There was 3rd-degree inhibition in the white blood cells, hemoglobin, and platelets. The three female patients suffered menstrual disorders during the course of radiation. Two female patients with heavy menstruation suffered 3rd-degree anemia inhibition, and 2 patients suffered amenorrhea after radiotherapy. Although menstrual cycle was normal, the third patient was not pregnant. Conclusion. CSI with HT is convenient for clinical practice, and the side effects are mild. With good conformity and uniformity, VMAT can also be used for selection in CSI. For poor conformity, 3D-CRT should not be the priority selection for CSI. In female patients, the ovaries should be protected.

  12. Radiation dose delivered to the proximal penis as a predictor of the risk of erectile dysfunction after three-dimensional conformal radiotherapy for localized prostate cancer

    International Nuclear Information System (INIS)

    Wernicke, A. Gabriella; Valicenti, Richard; DiEva, Kelly; Houser, Christopher; Pequignot, Ed

    2004-01-01

    Purpose/objective: In this study, we evaluated in a serial manner whether radiation dose to the bulb of the penis is predictive of erectile dysfunction, ejaculatory difficulty (EJ), and overall satisfaction with sex life (quality of life) by using serial validated self-administered questionnaires. Methods and materials: Twenty-nine potent men with AJCC Stage II prostate cancer treated with three-dimensional conformal radiation therapy alone to a median dose 72.0 Gy (range: 66.6-79.2 Gy) were evaluated by determining the doses received by the penile bulb. The penile bulb was delineated volumetrically, and the dose-volume histogram was obtained on each patient. Results: The median follow-up time was 35 months (range, 16-43 months). We found that for D 30 , D 45 , D 60 , and D 75 (doses to a percent volume of PB: 30%, 45%, 60%, and 75%), higher than the corresponding median dose (defined as high-dose group) correlated with an increased risk of impotence (erectile dysfunction firmness score = 0) (odds ratio [OR] = 7.5, p = 0.02; OR = 7.5, p = 0.02; OR = 8.6, p = 0.008; and OR = 6.9, p = 0.015, respectively). Similarly, for EJD D 30 , D 45 , D 60 , and D 75 , doses higher than the corresponding median ones correlated with worsening ejaculatory function score (EJ = 0 or 1) (OR = 8, p = 0.013; OR = 8, p 0.013; OR = 9.2, p = 0.015; and OR = 8, p = 0.026, respectively). For quality of life, low (≤median dose) dose groups of patients improve over time, whereas high-dose groups of patients worsen. Conclusions: This study supports the existence of a penile bulb dose-volume relationship underlying the development of radiation-induced erectile dysfunction. Our data may guide the use of inverse treatment planning to maximize the probability of maintaining sexual potency after radiation therapy

  13. Three-dimensional dose-response models of competing risks and natural life span

    International Nuclear Information System (INIS)

    Raabe, O.G.

    1987-01-01

    Three-dimensional dose-rate/time/response surfaces for chronic exposure to carcinogens, toxicants, and ionizing radiation dramatically clarify the separate and interactive roles of competing risks. The three dimensions are average dose rate, exposure time, and risk. An illustration with computer graphics shows the contributions with the passage of time of the competing risks of death from radiation pneumonitis/fibrosis, lung cancer, and natural aging consequent to the inhalation of plutonium-239 dioxide by beagles. These relationships are further evaluated by mathematical stripping with three-dimensional illustrations that graphically show the resultant separate contribution of each fatal effect. Radiation pneumonitis predominates at high dose rates and lung cancer at intermediate dose rates. Low dose rates result in spontaneous deaths from natural aging, yielding a type of practical threshold for lung cancer induction. Risk assessment is benefited by the insights that become apparent with these three-dimensional models. The improved conceptualization afforded by them contributes to the planning and evaluation of epidemiological analyses and experimental studies involving chronic exposure to toxicants

  14. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    Science.gov (United States)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-01-01

    Introduction Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. Methods A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. Results The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. Conclusion The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques. PMID:26229623

  15. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    International Nuclear Information System (INIS)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham

    2013-01-01

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques

  16. Carcinoma of the anal canal: Intensity modulated radiation therapy (IMRT) versus three-dimensional conformal radiation therapy (3DCRT)

    Energy Technology Data Exchange (ETDEWEB)

    Sale, Charlotte; Moloney, Phillip; Mathlum, Maitham [Andrew Love Cancer Centre, Geelong Hospital, Geelong, Victoria (Australia)

    2013-12-15

    Patients with anal canal carcinoma treated with standard conformal radiotherapy frequently experience severe acute and late toxicity reactions to the treatment area. Roohipour et al. (Dis Colon Rectum 2008; 51: 147–53) stated a patient's tolerance of chemoradiation to be an important prediction of treatment success. A new intensity modulated radiation therapy (IMRT) technique for anal carcinoma cases has been developed at the Andrew Love Cancer Centre aimed at reducing radiation to surrounding healthy tissue. A same-subject repeated measures design was used for this study, where five anal carcinoma cases at the Andrew Love Cancer Centre were selected. Conformal and IMRT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 54 Gray (Gy) over a course of 30 fractions to the primary site. The IMRT plans resulted in improved dosimetry to the planning target volume (PTV) and reduction in radiation to the critical structures (bladder, external genitalia and femoral heads). Statistically there was no difference between the IMRT and conformal plans in the dose to the small and large bowel; however, the bowel IMRT dose–volume histogram (DVH) doses were consistently lower. The IMRT plans were superior to the conformal plans with improved dose conformity and reduced radiation to the surrounding healthy tissue. Anecdotally it was found that patients tolerated the IMRT treatment better than the three-dimensional (3D) conformal radiation therapy. This study describes and compares the planning techniques.

  17. Analysis of biopsy outcome after three-dimensional conformal radiation therapy of prostate cancer using dose-distribution variables and tumor control probability models

    International Nuclear Information System (INIS)

    Levegruen, Sabine; Jackson, Andrew; Zelefsky, Michael J.; Venkatraman, Ennapadam S.; Skwarchuk, Mark W.; Schlegel, Wolfgang; Fuks, Zvi; Leibel, Steven A.; Ling, C. Clifton

    2000-01-01

    Purpose: To investigate tumor control following three-dimensional conformal radiation therapy (3D-CRT) of prostate cancer and to identify dose-distribution variables that correlate with local control assessed through posttreatment prostate biopsies. Methods and Material: Data from 132 patients, treated at Memorial Sloan-Kettering Cancer Center (MSKCC), who had a prostate biopsy 2.5 years or more after 3D-CRT for T1c-T3 prostate cancer with prescription doses of 64.8-81 Gy were analyzed. Variables derived from the dose distribution in the PTV included: minimum dose (Dmin), maximum dose (Dmax), mean dose (Dmean), dose to n% of the PTV (Dn), where n = 1%, ..., 99%. The concept of the equivalent uniform dose (EUD) was evaluated for different values of the surviving fraction at 2 Gy (SF 2 ). Four tumor control probability (TCP) models (one phenomenologic model using a logistic function and three Poisson cell kill models) were investigated using two sets of input parameters, one for low and one for high T-stage tumors. Application of both sets to all patients was also investigated. In addition, several tumor-related prognostic variables were examined (including T-stage, Gleason score). Univariate and multivariate logistic regression analyses were performed. The ability of the logistic regression models (univariate and multivariate) to predict the biopsy result correctly was tested by performing cross-validation analyses and evaluating the results in terms of receiver operating characteristic (ROC) curves. Results: In univariate analysis, prescription dose (Dprescr), Dmax, Dmean, dose to n% of the PTV with n of 70% or less correlate with outcome (p 2 : EUD correlates significantly with outcome for SF 2 of 0.4 or more, but not for lower SF 2 values. Using either of the two input parameters sets, all TCP models correlate with outcome (p 2 , is limited because the low dose region may not coincide with the tumor location. Instead, for MSKCC prostate cancer patients with their

  18. Potency following high-dose three-dimensional conformal radiotherapy and the impact of prior major urologic surgical procedures in patients treated for prostate cancer

    International Nuclear Information System (INIS)

    Chinn, Daniel M.; Holland, John; Crownover, Richard L.; Roach, Mack

    1995-01-01

    Purpose: To assess the impact of high-dose three-dimensional conformal radiotherapy (3DCRT) on potency in patients treated for clinically localized prostate cancer and to identify factors that might predict the outcome of sexual function following treatment. Methods and Materials: One hundred twenty-four consecutive patients treated with 3DCRT for localized prostate cancer at UCSF between 1991-1993 were included in this retrospective analysis. Patient responses were obtained from a mailed questionnaire, telephone interviews, or departmental records. Median follow-up was 21 months. Results: Sixty patients reported having sexual function prior to 3DCRT, including 47 who were fully potent and 13 who were marginally potent. Of the remaining 64 patients, 45 were impotent, 7 were on hormones, 1 was status-postorchiectomy, and 11 were not evaluable. Following 3DCRT, 37 of 60 patients (62%) retained sexual function sufficient for intercourse. Of those with sexual function before irradiation, 33 of 47 (70%) of patients fully potent and 4 of 13 (31%) of patients marginally potent maintained function sufficient for intercourse (p < 0.01). Potency was retained in 6 of 15 (40%) patients with a history of a major urologic surgical procedure (MUSP) and in 31 of 45 (69%) with no history of a MUSP (p < 0.04). Transurethral resection of the prostate was the MUSP in eight of these patients, with four (50%) maintaining sexual function. Conclusions: Patients who receive definitive 3DCRT for localized prostate cancer appear to maintain potency similar to patients treated with conventional radiotherapy. However, patients who are marginally potent at presentation or who have a history of a MUSP appear to be at increased risk of impotence following 3DCRT

  19. On-line estimations of delivered radiation doses in three-dimensional conformal radiotherapy treatments of carcinoma uterine cervix patients in linear accelerator.

    Science.gov (United States)

    Putha, Suman Kumar; Saxena, P U; Banerjee, S; Srinivas, Challapalli; Vadhiraja, B M; Ravichandran, Ramamoorthy; Joan, Mary; Pai, K Dinesh

    2016-01-01

    Transmission of radiation fluence through patient's body has a correlation to the planned target dose. A method to estimate the delivered dose to target volumes was standardized using a beam level 0.6 cc ionization chamber (IC) positioned at electronic portal imaging device (EPID) plane from the measured transit signal (S t ) in patients with cancer of uterine cervix treated with three-dimensional conformal radiotherapy (3DCRT). The IC with buildup cap was mounted on linear accelerator EPID frame with fixed source to chamber distance of 146.3 cm, using a locally fabricated mount. S t s were obtained for different water phantom thicknesses and radiation field sizes which were then used to generate a calibration table against calculated midplane doses at isocenter (D iso,TPS ), derived from the treatment planning system. A code was developed using MATLAB software which was used to estimate the in vivo dose at isocenter (D iso,Transit ) from the measured S t s. A locally fabricated pelvic phantom validated the estimations of D iso,Transit before implementing this method on actual patients. On-line dose estimations were made (3 times during treatment for each patient) in 24 patients. The D iso,Transit agreement with D iso,TPS in phantom was within 1.7% and the mean percentage deviation with standard deviation is -1.37% ±2.03% ( n = 72) observed in patients. Estimated in vivo dose at isocenter with this method provides a good agreement with planned ones which can be implemented as part of quality assurance in pelvic sites treated with simple techniques, for example, 3DCRT where there is a need for documentation of planned dose delivery.

  20. Three-Dimensional Conformal Simultaneously Integrated Boost Technique for Breast-Conserving Radiotherapy

    International Nuclear Information System (INIS)

    Laan, Hans Paul van der; Dolsma, Wil V.; Maduro, John H.; Korevaar, Erik W.; Hollander, Miranda; Langendijk, Johannes A.

    2007-01-01

    Purpose: To compare the target coverage and normal tissue dose with the simultaneously integrated boost (SIB) and the sequential boost technique in breast cancer, and to evaluate the incidence of acute skin toxicity in patients treated with the SIB technique. Methods and Materials: Thirty patients with early-stage left-sided breast cancer underwent breast-conserving radiotherapy using the SIB technique. The breast and boost planning target volumes (PTVs) were treated simultaneously (i.e., for each fraction, the breast and boost PTVs received 1.81 Gy and 2.3 Gy, respectively). Three-dimensional conformal beams with wedges were shaped and weighted using forward planning. Dose-volume histograms of the PTVs and organs at risk with the SIB technique, 28 x (1.81 + 0.49 Gy), were compared with those for the sequential boost technique, 25 x 2 Gy + 8 x 2 Gy. Acute skin toxicity was evaluated for 90 patients treated with the SIB technique according to Common Terminology Criteria for Adverse Events, version 3.0. Results: PTV coverage was adequate with both techniques. With SIB, more efficiently shaped boost beams resulted in smaller irradiated volumes. The mean volume receiving ≥107% of the breast dose was reduced by 20%, the mean volume outside the boost PTV receiving ≥95% of the boost dose was reduced by 54%, and the mean heart and lung dose were reduced by 10%. Of the evaluated patients, 32.2% had Grade 2 or worse toxicity. Conclusion: The SIB technique is proposed for standard use in breast-conserving radiotherapy because of its dose-limiting capabilities, easy implementation, reduced number of treatment fractions, and relatively low incidence of acute skin toxicity

  1. Application of biological dose concept in dose optimization for conformal radiotherapy of prostate carcinoma

    International Nuclear Information System (INIS)

    Li Yunhai; Liao Yuan; Zhou Lijun; Pan Ziqiang; Feng Yan

    2003-01-01

    Objective: On basis of physical dose optimization, LQ model was used to investigate the difference between the curves of biological effective dose and physical isodose. The influence of applying the biological dose concept on three dimensional conformal radiotherapy of prostate carcinoma was discussed. Methods: Four treatment plannings were designed for physical dose optimization: three fields, four-box fields, five fields and six fields. Target dose uniformity and protection of the critical tissue-rectum were used as the principal standard for designing the treatment planning. Biological effective dose (BED) was calculated by LQ model. The difference between the BED curve drawn in the central layer and the physical isodose curve was studied. The difference between the adjusted physical dose (APD) and the physical dose was also studied. Results: Five field planning was the best in target dose uniformity and protection of the critical tissue-rectum. The physical dose was uniform in the target, but the biological effective doses revealed great discrepancy in the biological model. Adjusted physical dose distribution also displayed larger discrepancy than the physical dose unadjusted. Conclusions: Intensified Modulated Radiotherapy (IMRT) technique with inversion planning using biological dose concept may be much more advantageous to reach a high tumor control probability and low normal tissue complication probability

  2. Three dimensional conformal radiation therapy in pediatric parameningeal rhabdomyosarcomas

    International Nuclear Information System (INIS)

    Michalski, Jeff M.; Harms, William B.; Purdy, James A.; Sur, Ranjan K.

    1995-01-01

    Purpose: We evaluated the utility of three dimensional (3D) treatment planning in the management of children with parameningeal head and neck rhabdomyosarcomas. Methods and Materials: Five children with parameningeal rhabdomyosarcoma were referred for treatment at our radiation oncology center from May 1990 through January 1993. Each patient was evaluated, staged, and treated according to the Intergroup Rhabdomyosarcoma Study. Patients were immobilized and underwent a computed tomography scan with contrast in the treatment position. Tumor and normal tissues were identified with assistance from a diagnostic radiologist and defined in each slice. The patients were then planned and treated with the assistance of a 3D treatment planning system. A second plan was then devised by another physician without the benefit of the 3D volumetric display. The target volumes designed with the 3D system and the two-dimensional (2D) method were then compared. The dosimetric coverage to tumor, tumor plus margin, and normal tissues was also compared with the two methods of treatment planning. Results: The apparent size of the gross tumor volume was underestimated with the conventional 2D planning method relative to the 3D method. When margin was added around the gross tumor to account for microscopic extension of disease in the 2D method, the expected area of coverage improved relative to the 3D method. In each circumstance, the minimum dose that covered the gross tumor was substantially less with the 2D method than with the 3D method. The inadequate dosimetric coverage was especially pronounced when the necessary margin to account for subclinical disease was added. In each case, the 2D plans would have delivered substantial dose to adjacent normal tissues and organs, resulting in a higher incidence of significant complications. Conclusions: 3D conformal radiation therapy has a demonstrated advantage in the treatment of sarcomas of the head and neck. The improved dosimetric coverage

  3. Full three-dimensional isotropic carpet cloak designed by quasi-conformal transformation optics.

    Science.gov (United States)

    Silva, Daniely G; Teixeira, Poliane A; Gabrielli, Lucas H; Junqueira, Mateus A F C; Spadoti, Danilo H

    2017-09-18

    A fully three-dimensional carpet cloak presenting invisibility in all viewing angles is theoretically demonstrated. The design is developed using transformation optics and three-dimensional quasi-conformal mapping. Parametrization strategy and numerical optimization of the coordinate transformation deploying a quasi-Newton method is applied. A discussion about the minimum achievable anisotropy in the 3D transformation optics is presented. The method allows to reduce the anisotropy in the cloak and an isotropic medium could be considered. Numerical simulations confirm the strategy employed enabling the design of an isotropic reflectionless broadband carpet cloak independently of the incident light direction and polarization.

  4. Prospective randomized trail on chrono-chemotherapy + late course three dimensional conformal radio-therapy and conventional chemotherapy plus radiotherapy for nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Jin Feng; Ouyang Jinling; Dong Hongmin; Wu Weili; Chen Haixia; He Zhihui

    2005-01-01

    Objective: To compare the therapeutic effects, toxic side effects of late-course three dimensional conformal radiotherapy plus chrono-chemotherapy (DDP + 5-FU/CF) and conventional radiotherapy plus chemotherapy for nasopharyngeal carcinoma (NPC). Methods: Eighty -six NPC patients admitted from Feb. 2001 to Jan. 2002 were divided randomly into two groups: 1. Chrono-chemotherapy + late course three dimensional conformal radiotherapy(CCR) group-44 patients were treated by late course three dimensional conformal radio-therapy plus chrono-chemotherapy, and 2. Routine-chemotherapy-radiotherapy (RCR) group-42 patients were treated by routine chemotherapy plus radiotherapy. The patients in CCR and RCR group were comparable in age, KPS, stage and pathology. All patients were treated by combined chemotherapy and radiotherapy, with chemotherapy stared 2 weeks ahead of radiotherapy. Chemotherapy: Braun pump was used in all drug infusions; 1. CCR group-DDP 80 mg/ m 2 starting from 10:00 until 22:00, 5-Fu 750 mg/d/m 2 starting from 22:00 until 10:00 next day, CF 200 mg/d/m 2 starting from 10:00 every day, infused at normal speed. These drugs were given for 3 days, 14 days as one cycle, totally 2 cycle, and 2. RCR group-with the same drugs at the same total dose, only with the difference being DDP and CF given QD, starting from 10:00 but at the normal speed. 5-Fu was given through-out the day and continuously for 3 days, totally for 2 cycles. Radiotherapy: linear accelerator irradiation was given to either group. Composite facio-cervical field + anterior cervical tangential field to D T 40 Gy/4w, followed by the coned down per-auricular field plus anterior tangential field or β beam irradiation. In CCR group, after D T 40gy/4w, late course 3-dimensional conformal radiotherapy (3DCRT) was used to add D T 30Gy/3w. In RCR group, routine radiotherapy of 40 Gy/w was supplemented with 30 Gy/3w. The total dose in either group was 70 Gy/7w at the nasopharynx, D T 60-70 Gy/6-7w at the

  5. Development of model plans in three dimensional conformal radiotherapy for brain tumors

    International Nuclear Information System (INIS)

    Pyo, Hongryull; Kim, Gwieon; Keum, Kichang; Chang, Sekyung; Suh, Changok; Lee, Sanghoon

    2002-01-01

    Three dimensional conformal radiotherapy planning is being used widely for the treatment of patients with brain tumor. However, it takes much time to develop an optimal treatment plan, therefore, it is difficult to apply this technique to all patients. To increase the efficiency of this technique, we need to develop standard radiotherapy plans for each site of the brain. Therefore we developed several 3 dimensional conformal radiotherapy plans (3D plans) for tumors at each site of brain, compared them with each other, and with 2 dimensional radiotherapy plans. Finally model plans for each site of the brain were decided. Imaginary tumors, with sizes commonly observed in the clinic, were designed for each site of the brain and drawn on CT images. The planning target volumes (PTVs) were as follows; temporal tumor-5.7 x 8.2 x 7.6 cm, suprasellar tumor-3 x 4 x 4.1 cm, thalamic tumor-3.1 x 5.9 x 3.7 cm, frontoparietal tumor-5.5 x 7 x 5.5 cm, and occipitoparietal tumor-5 x 5.5 x 5 cm. Plans using parallel opposed 2-portals and/or 3 portals including fronto-vertex and 2 lateral fields were developed manually as the conventional 2D plans, and 3D noncoplanar conformal plans were developed using beam's eye view and the automatic block drawing tool. Total tumor dose was 54 Gy for a suprasellar tumor, 59.4 Gy and 72 Gy for the other tumors. All dose plans (including 2D plans) were calculated using 3D plan software. Developed plans were compared with each other using dose-volume histograms (DVH), normal tissue complication probabilities (NTCP) and variable dose statistic values (minimum, maximum and mean dose, D5, V83, V85 and V95). Finally a best radiotherapy plan for each site of brain was selected. 1) Temporal tumor; NTCPs and DVHs of the normal tissue of all 3D plans were superior to 2D plans and this trend was more definite when total dose was escalated to 72 Gy (NTCPs of normal brain 2D plans: 27%, 8% → 3D plans: 1%, 1%). Various dose statistic values did not show any

  6. Accelerated hypofractionated three-dimensional conformal radiation therapy in the treatment of non-small cell lung cancer

    International Nuclear Information System (INIS)

    Yu Jinming; Zheng Aiqing; Yu Yonghua; Wang Xuetao; Yuan Shuanghu; Han Dali; Li Kunhai

    2005-01-01

    Objective: To evaluate the effect and complication of non-small-cell lung cancer (NSCLC) treated with accelerated hypofractionated three dimensional conforms] radiation therapy (3DCRT). Methods: There were squamous carcinoma 21, adenocarcinoma 7, squamous-adenocarcinoma 4 and other cancer 3. There were 17 stage I and 18 stage II. Thirty-five patients of NSCLC were treated with a dose of 30-48 Gy in 6 or 8 Gy per fraction, 3 times a week. The outcome of these patients Was analyzed. Results: The overall 1-, 2- and 3- Year survival rate was 78.2%, 46.9% and 36.3%, respectively. The 1- and 2-year recurrence-free survival rate was 64.6 % and 39.7 %, respectively. The acute radiation pneumonitis and late lung fibrosis rates were high. Univariate analysis showed that Vm was a significant predictor of acute radiation pneumonitis. Conclusion: Compared with accelerated hypofractionated irradiation, the routine conventional fractionated radiation therapy may be preferred for more patients of NSCLC. (authors)

  7. Comparison of acute and subacute genitourinary and gastrointestinal adverse events of radiotherapy for prostate cancer using intensity-modulated radiation therapy, three-dimensional conformal radiation therapy, permanent implant brachytherapy and high-dose-rate brachytherapy

    NARCIS (Netherlands)

    Morimoto, Masahiro; Yoshioka, Yasuo; Konishi, Koji; Isohashi, Fumiaki; Takahashi, Yutaka; Ogata, Toshiyuki; Koizumi, Masahiko; Teshima, Teruki; Bijl, Henk P; van der Schaaf, Arjen; Langendijk, Johannes A; Ogawa, Kazuhiko

    2014-01-01

    AIMS AND BACKGROUND: To examine acute and subacute urinary and rectal toxicity in patients with localized prostate cancer monotherapeutically treated with the following four radiotherapeutic techniques: intensity-modulated radiation therapy, three-dimensional conformal radiation therapy,

  8. Fast, three-dimensional, MR Imaging for polymer gel dosimetric applications involving high dose and steep dose gradients

    International Nuclear Information System (INIS)

    Sandilos, Panagiotis; Baras, Panagiotis; Georgiou, Evangelos; Dardoufas, Konstantinos; Karaiskos, Pantelis; Papagiannis, Panagiotis; Paschalis, Theodoros; Tatsis, Elias; Torrens, Michael; Vlahos, Lampros

    2006-01-01

    Polymer gels constitute water equivalent integrating detectors, which, combined with magnetic resonance imaging (MRI), can provide accurate three dimensional (3D) dose distributions in contemporary radiotherapy applications where the small field dimensions and steep dose gradients induce limitations to conventional dosimeters. One of the main obstacles for adapting the method for routine use in the clinical setting is the cost effectiveness of the MRI readout method. Currently, optimized Carr-Purcell-Meiboom-Gill (CPMG) multiple spin echo imaging pulse sequences are commonly used which however result in long imaging times. This work evaluates the efficiency of 3D, dual-echo, k-space segmented turbo spin echo (TSE) scanning sequences for accurate dosimetry with sub-millimetre spatial resolution in strenuous radiation therapy applications. PABIG polymer gel dosimeters were irradiated with an 192 Ir High Dose Rate brachytherapy source, the 4 mm and 8 mm collimator helmets of a gamma knife unit and a custom made x-knife collimator of 1 cm diameter. Profile and dose distribution measurements using TSE are benchmarked against corresponding findings obtained by the commonly used, but time consuming, CPMG sequence as well as treatment planning calculations, Monte Carlo (MC) simulations and film measurements. The implementation of a high Turbo factor was found to provide comparable accuracy, allowing a 64-fold MRI scan acceleration compared to conventional multi-echo sequences. The availability of TSE sequences in typical MRI installations greatly facilitates the introduction of polymer gel dosimetry in the clinical environment as a practicable tool for the determination of full 3D dose distributions in contemporary radiotherapy applications

  9. Fast, three-dimensional, MR Imaging for polymer gel dosimetric applications involving high dose and steep dose gradients

    Energy Technology Data Exchange (ETDEWEB)

    Sandilos, Panagiotis [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece); Baras, Panagiotis [Philips Hellas Medical Systems, 44 Kifissias Ave., Maroussi 151 25, Athens (Greece); Georgiou, Evangelos [Medical Physics Department, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece); Dardoufas, Konstantinos [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece): Hygeia Hospital, Kiffisias Avenue and 4 Erythrou Stavrou, Marousi, 151 23 Athens (Greece); Karaiskos, Pantelis [Medical Physics Department, University of Athens, 75 Mikras Asias, 115 27 Athens (Greece): Hygeia Hospital, Kiffisias Avenue and 4 Erythrou Stavrou, Marousi, 151 23 Athens (Greece)]. E-mail: p.karaiskos@hygeia.gr; Papagiannis, Panagiotis [Physics Department, Nuclear and Particle Physics Section, University of Athens, Panepistimioupolis, Ilisia, 157 71 Athens (Greece); Paschalis, Theodoros [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece); Tatsis, Elias [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece); Torrens, Michael [Hygeia Hospital, Kiffisias Avenue and 4 Erythrou Stavrou, Marousi, 151 23 Athens (Greece); Vlahos, Lampros [Department of Radiology, Medical School, University of Athens, Areteion Hospital, 76 Vas. Sofias Ave., 115 28 Athens (Greece)

    2006-12-20

    Polymer gels constitute water equivalent integrating detectors, which, combined with magnetic resonance imaging (MRI), can provide accurate three dimensional (3D) dose distributions in contemporary radiotherapy applications where the small field dimensions and steep dose gradients induce limitations to conventional dosimeters. One of the main obstacles for adapting the method for routine use in the clinical setting is the cost effectiveness of the MRI readout method. Currently, optimized Carr-Purcell-Meiboom-Gill (CPMG) multiple spin echo imaging pulse sequences are commonly used which however result in long imaging times. This work evaluates the efficiency of 3D, dual-echo, k-space segmented turbo spin echo (TSE) scanning sequences for accurate dosimetry with sub-millimetre spatial resolution in strenuous radiation therapy applications. PABIG polymer gel dosimeters were irradiated with an {sup 192}Ir High Dose Rate brachytherapy source, the 4 mm and 8 mm collimator helmets of a gamma knife unit and a custom made x-knife collimator of 1 cm diameter. Profile and dose distribution measurements using TSE are benchmarked against corresponding findings obtained by the commonly used, but time consuming, CPMG sequence as well as treatment planning calculations, Monte Carlo (MC) simulations and film measurements. The implementation of a high Turbo factor was found to provide comparable accuracy, allowing a 64-fold MRI scan acceleration compared to conventional multi-echo sequences. The availability of TSE sequences in typical MRI installations greatly facilitates the introduction of polymer gel dosimetry in the clinical environment as a practicable tool for the determination of full 3D dose distributions in contemporary radiotherapy applications.

  10. Three-dimensional conformal radiation may deliver considerable dose of incidental nodal irradiation in patients with early stage node-negative non-small cell lung cancer when the tumor is large and centrally located

    International Nuclear Information System (INIS)

    Zhao Lujun; Chen Ming; Haken, Randall ten; Chetty, Indrin; Chapet, Olivier; Hayman, James A.; Kong Fengming

    2007-01-01

    Background and purpose: To determine the dose to regional nodal stations in patients with T 1-3 N 0 M 0 non-small cell lung cancer (NSCLC) treated with three-dimensional conformal radiation therapy (3DCRT) without intentional elective nodal irradiation (ENI). Materials and methods: Twenty-three patients with medically inoperable T 1-3 N 0 M 0 NSCLC were treated with 3DCRT without ENI. Hilar and mediastinal nodal regions were contoured on planning CT. The prescription dose was normalized to 70 Gy. Equivalent uniform dose (EUD) and other dosimetric parameters (e.g., V 40 ) were calculated for each nodal station. Results: The median EUD for the whole group ranged from 0.4 to 4.4 Gy for all elective nodal regions. Gross tumor volume (GTV) and the relationship between GTV and hilum were significantly correlated with irradiation dose to ipsilateral hilar nodal regions (P 3 (diameter ∼ 4 cm) and or having any overlap with hilum, the median EUDs were 9.6, 22.6, and 62.9 Gy for ipsilateral lower paratracheal, subcarinal, and ipsilateral hilar regions, respectively. The corresponding median V 40 were 32.5%, 39.3%, and 97.6%, respectively. Conclusions: Although incidental nodal irradiation dose is low in the whole group, the dose to high-risk nodal regions is considerable in patients with T 1-3 N 0 NSCLC when the primary is large and/or centrally located

  11. Hypofractionated three-dimensional conformal radiotherapy for medically inoperable early stage

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joo Ho; Wu, Hong Gyun; KIm, Hak Jae; Park, Charn Il; Lee, Se Hoon; Kim, Dong Wan; Heo, Dae Seong [Seoul National University College of Medicine, Seou (Korea, Republic of)

    2013-01-15

    The purpose of this study was to assess the clinical outcomes of hypofractionated radiotherapy (HFRT) with three-dimensional conformal technique for medically inoperable patients with early stage non-small-cell lung cancer (NSCLC) and to evaluate prognostic factors. We performed a retrospective review of 26 patients who underwent HFRT for early stage NSCLC between September 2005 and August 2011. Only clinical stage T1-3N0 was included. The median RT dose was 70 Gy (range, 60 to 72 Gy) and the median biologically equivalent dose (BED) was 94.5 Gy (range, 78.0 to 100.8 Gy). In 84.6% of patients, 4 Gy per fraction was used. Neoadjuvant chemotherapy with paclitaxel and cisplatin was given to 2 of 26 patients. The median follow-up time for surviving patients was 21 months (range, 13 to 49 months). The overall response rate was 53.9%, and the initial local control rate was 100%. The median survival duration was 27.8 months. Rates of 2-year overall survival, progression-free survival (PFS), local control (LC), and locoregional-free survival (LRFS) were 54.3%, 61.1%, 74.6%, and 61.9%, respectively. Multivariate analysis showed that BED (>90 vs. {<=}90 Gy) was an independent prognostic factor influencing PFS, LC, and LRFS. Severe toxicities over grade 3 were not observed. Radical HFRT can yield satisfactory disease control with acceptable rates of toxicities in medically inoperable patients with early stage NSCLC. HFRT is a viable alternative for clinics and patients ineligible for stereotactic ablative radiotherapy. BED over 90 Gy and 4 Gy per fraction might be appropriate for HFRT.

  12. Estimate of the damage in organs induced by neutrons in three-dimensional conformal radiotherapy; Estimacion del dano en organos inducido por neutrones en radioterapia conformada en 3D

    Energy Technology Data Exchange (ETDEWEB)

    Benites R, J. L. [Centro Estatal de Cancerologia de Nayarit, Servicio de Seguridad Radiologica, Calzada de la Cruz 118 sur, 63000 Tepic, Nayarit (Mexico); Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Uribe, M. del R., E-mail: jlbenitesr@prodigy.net.mx [Instituto Tecnico Superior de Radiologia, Calle Leon No. 129, 63000 Tepic, Nayarit (Mexico)

    2014-08-15

    By means of Monte Carlo methods was considered the damage in the organs, induced by neutrons, of patients with cancer that receive treatment in modality of three-dimensional conformal radiotherapy (3D-CRT) with lineal accelerator Varian Ix. The objective of this work was to estimate the damage probability in radiotherapy patients, starting from the effective dose by neutrons in the organs and tissues out of the treatment region. For that a three-dimensional mannequin of equivalent tissue of 30 x 100 x 30 cm{sup 3} was modeled and spherical cells were distributed to estimate the Kerma in equivalent tissue and the absorbed dose by neutrons. With the absorbed dose the effective dose was calculated using the weighting factors for the organ type and radiation type. With the effective dose and the damage factors, considered in the ICRP 103, was considered the probability of damage induction in organs. (Author)

  13. Dose escalation using conformal high-dose-rate brachytherapy improves outcome in unfavorable prostate cancer.

    Science.gov (United States)

    Martinez, Alvaro A; Gustafson, Gary; Gonzalez, José; Armour, Elwood; Mitchell, Chris; Edmundson, Gregory; Spencer, William; Stromberg, Jannifer; Huang, Raywin; Vicini, Frank

    2002-06-01

    To overcome radioresistance for patients with unfavorable prostate cancer, a prospective trial of pelvic external beam irradiation (EBRT) interdigitated with dose-escalating conformal high-dose-rate (HDR) prostate brachytherapy was performed. Between November 1991 and August 2000, 207 patients were treated with 46 Gy pelvic EBRT and increasing HDR brachytherapy boost doses (5.50-11.5 Gy/fraction) during 5 weeks. The eligibility criteria were pretreatment prostate-specific antigen level >or=10.0 ng/mL, Gleason score >or=7, or clinical Stage T2b or higher. Patients were divided into 2 dose levels, low-dose biologically effective dose 93 Gy (149 patients). No patient received hormones. We used the American Society for Therapeutic Radiology and Oncology definition for biochemical failure. The median age was 69 years. The mean follow-up for the group was 4.4 years, and for the low and high-dose levels, it was 7.0 and 3.4 years, respectively. The actuarial 5-year biochemical control rate was 74%, and the overall, cause-specific, and disease-free survival rate was 92%, 98%, and 68%, respectively. The 5-year biochemical control rate for the low-dose group was 52%; the rate for the high-dose group was 87% (p failure. The Radiation Therapy Oncology Group Grade 3 gastrointestinal/genitourinary complications ranged from 0.5% to 9%. The actuarial 5-year impotency rate was 51%. Pelvic EBRT interdigitated with transrectal ultrasound-guided real-time conformal HDR prostate brachytherapy boost is both a precise dose delivery system and a very effective treatment for unfavorable prostate cancer. We demonstrated an incremental beneficial effect on biochemical control and cause-specific survival with higher doses. These results, coupled with the low risk of complications, the advantage of not being radioactive after implantation, and the real-time interactive planning, define a new standard for treatment.

  14. Comparison between conventional and three-dimensional conformal treatment planning for radiotherapy of cerebral tumors

    International Nuclear Information System (INIS)

    Caudrelier, J.M.; Auliard, A.; Sarrazin, T.; Gibon, D.; Coche-Dequeant, B.; Castelain, B.

    2001-01-01

    Comparison between conventional and three-dimensional conformal treatment planning for radiotherapy of cerebral tumors. Purpose. - We prospectively compared a conventional treatment planning (PT2D) and 3-dimensional conformal treatment planning (PT3D) for radiotherapy of cerebral tumours. Patients and methods.- Patients treated between 1/10/98 and 1/4/99 by irradiation for cerebral tumours were analysed. For each case, we planned PT2D using conventional orthogonal x-ray films, and afterward, PT3D using CT scan. Gross tumor volume, planning target volume and normal tissue volumes were defined. Dose was prescribed according to report 50 of the International Commission on Radiation Units and Measurements (ICRU). We compared surfaces of sagittal view targets defined on PT2D and PT3D and called them S2D and S3D, respectively. Irradiated volumes by 90% isodoses (VE-90%) and normal tissue volumes irradiated by 20, 50, 90% isodoses were calculated and compared using Student's paired t-test. Results. -There was a concordance of 84% of target surfaces defined on PT2D and PT3D. Percentages of target surface under- or-over defined by PT2D were 16 and 13% respectively. VE-90% was decreased by 15% (p = 0.07) with PT3D. Normal brain volume irradiated by 90% isodose was decreased by 27% with PT3D (p = 0.04). Conclusion.- For radiotherapy of cerebral tumors using only coplanar beams, PT3D leads to a reduction of normal brain tissue irradiated. We recommend PT3D for radiotherapy of cerebral tumors, particularly for low-grade or benign tumors (meningiomas, neuromas, etc.). (authors)

  15. Predictive factors of gastroduodenal toxicity in cirrhotic patients after three-dimensional conformal radiotherapy for hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Kim, Haeyoung; Lim, Do Hoon; Paik, Seung Woon; Yoo, Byung Chul; Koh, Kwang Gheol; Lee, Joon Hyoek; Choi, Moon Seok; Park, Won; Park, Hee Chul; Huh, Seung Jae; Choi, Doo Ho; Ahn, Yong Chan

    2009-01-01

    Background and purpose: To identify predictive factors for the development of gastroduodenal toxicity (GDT) in cirrhotic patients treated with three-dimensional conformal radiotherapy (3D-CRT) for hepatocellular carcinoma (HCC). Materials and methods: We retrospectively analyzed dose-volume histograms (DVHs) and clinical records of 73 cirrhotic patients treated with 3D-CRT for HCC. The median radiation dose was 36 Gy (range, 30-54 Gy) with a daily dose of 3 Gy. The grade of GDT was defined by the Common Toxicity Criteria Version 2. The predictive factors of grade 3 GDT were identified. Results: Grade 3 GDT was found in 9 patients. Patient's age and the percentage of gastroduodenal volume receiving more than 35 Gy (V 35 ) significantly affected the development of grade 3 GDT. Patients over 50 years of age developed grade 3 GDT more frequently than patients under 50 years of age. The risk of grade 3 GDT grew exponentially as V 35 increased. The 1-year actuarial rate of grade 3 GDT in patients with V 35 35 ≥5% (4% vs. 48%, p 35 were the most predictive factors for the development of grade 3 GDT in patients treated with RT.

  16. Weekly bi-fractionated 40 Gy three-dimensional conformational accelerated partial irradiation of breast: results of a phase II French pilot study

    International Nuclear Information System (INIS)

    Bourgier, C.; Pichenot, C.; Verstraet, R.; Heymann, S.; Biron, B.; Delaloge, S.; Garbay, J.R.; Marsiglia, H.; Bourhis, J.; Taghian, A.; Marsiglia, H.

    2010-01-01

    The authors report the first French experience of three-dimensional conformational and accelerated partial irradiation of breast. Twenty five patients have been concerned by this phase II trial. The prescribed total dose was 40 Gy, was delivered over 5 days in two daily fractions. Irradiation was performed with two 6 MV tangential mini-beams and a 6-22 MeV front electron beams. The planning target volume coverage was very good. Toxicity has been assessed. Healthy tissues (heart, lungs) are considerably protected. The acute and late toxicity is correct. Short communication

  17. Conformity index: A review

    International Nuclear Information System (INIS)

    Feuvret, Loic; Noel, Georges; Mazeron, Jean-Jacques; Bey, Pierre

    2006-01-01

    We present a critical analysis of the conformity indices described in the literature and an evaluation of their field of application. Three-dimensional conformal radiotherapy, with or without intensity modulation, is based on medical imaging techniques, three-dimensional dosimetry software, compression accessories, and verification procedures. It consists of delineating target volumes and critical healthy tissues to select the best combination of beams. This approach allows better adaptation of the isodose to the tumor volume, while limiting irradiation of healthy tissues. Tools must be developed to evaluate the quality of proposed treatment plans. Dosimetry software provides the dose distribution in each CT section and dose-volume histograms without really indicating the degree of conformity. The conformity index is a complementary tool that attributes a score to a treatment plan or that can compare several treatment plans for the same patient. The future of conformal index in everyday practice therefore remains unclear

  18. High-Efficiency Dye-Sensitized Solar Cell with Three-Dimensional Photoanode

    KAUST Repository

    Tétreault, Nicolas

    2011-11-09

    Herein, we present a straightforward bottom-up synthesis of a high electron mobility and highly light scattering macroporous photoanode for dye-sensitized solar cells. The dense three-dimensional Al/ZnO, SnO2, or TiO 2 host integrates a conformal passivation thin film to reduce recombination and a large surface-area mesoporous anatase guest for high dye loading. This novel photoanode is designed to improve the charge extraction resulting in higher fill factor and photovoltage for DSCs. An increase in photovoltage of up to 110 mV over state-of-the-art DSC is demonstrated. © 2011 American Chemical Society.

  19. High-Efficiency Dye-Sensitized Solar Cell with Three-Dimensional Photoanode

    KAUST Repository

    Té treault, Nicolas; Arsenault, É ric; Heiniger, Leo-Philipp; Soheilnia, Navid; Brillet, Jé ré mie; Moehl, Thomas; Zakeeruddin, Shaik; Ozin, Geoffrey A.; Grä tzel, Michael

    2011-01-01

    Herein, we present a straightforward bottom-up synthesis of a high electron mobility and highly light scattering macroporous photoanode for dye-sensitized solar cells. The dense three-dimensional Al/ZnO, SnO2, or TiO 2 host integrates a conformal passivation thin film to reduce recombination and a large surface-area mesoporous anatase guest for high dye loading. This novel photoanode is designed to improve the charge extraction resulting in higher fill factor and photovoltage for DSCs. An increase in photovoltage of up to 110 mV over state-of-the-art DSC is demonstrated. © 2011 American Chemical Society.

  20. Dose escalation using conformal high-dose-rate brachytherapy improves outcome in unfavorable prostate cancer

    International Nuclear Information System (INIS)

    Martinez, Alvaro A.; Gustafson, Gary; Gonzalez, Jose; Armour, Elwood; Mitchell, Chris; Edmundson, Gregory; Spencer, William; Stromberg, Jannifer; Huang, Raywin; Vicini, Frank

    2002-01-01

    Purpose: To overcome radioresistance for patients with unfavorable prostate cancer, a prospective trial of pelvic external beam irradiation (EBRT) interdigitated with dose-escalating conformal high-dose-rate (HDR) prostate brachytherapy was performed. Methods and Materials: Between November 1991 and August 2000, 207 patients were treated with 46 Gy pelvic EBRT and increasing HDR brachytherapy boost doses (5.50-11.5 Gy/fraction) during 5 weeks. The eligibility criteria were pretreatment prostate-specific antigen level ≥10.0 ng/mL, Gleason score ≥7, or clinical Stage T2b or higher. Patients were divided into 2 dose levels, low-dose biologically effective dose 93 Gy (149 patients). No patient received hormones. We used the American Society for Therapeutic Radiology and Oncology definition for biochemical failure. Results: The median age was 69 years. The mean follow-up for the group was 4.4 years, and for the low and high-dose levels, it was 7.0 and 3.4 years, respectively. The actuarial 5-year biochemical control rate was 74%, and the overall, cause-specific, and disease-free survival rate was 92%, 98%, and 68%, respectively. The 5-year biochemical control rate for the low-dose group was 52%; the rate for the high-dose group was 87% (p<0.001). Improvement occurred in the cause-specific survival in favor of the brachytherapy high-dose level (p=0.014). On multivariate analysis, a low-dose level, higher Gleason score, and higher nadir value were associated with increased biochemical failure. The Radiation Therapy Oncology Group Grade 3 gastrointestinal/genitourinary complications ranged from 0.5% to 9%. The actuarial 5-year impotency rate was 51%. Conclusion: Pelvic EBRT interdigitated with transrectal ultrasound-guided real-time conformal HDR prostate brachytherapy boost is both a precise dose delivery system and a very effective treatment for unfavorable prostate cancer. We demonstrated an incremental beneficial effect on biochemical control and cause

  1. Dosimetry analysis on radiation-induced acute esophagitis after three-dimensional conformal radiotherapy for non-small cell lung cancer

    International Nuclear Information System (INIS)

    ZZhu Shuchai; Cui Yanli; Li Juan; Liu Zhikun; Shen Wenbin; Su Jingwei; Wang Yuxiang

    2010-01-01

    Objective: To analyze the related factors with radiation-induced esophagitis after threedimensional conformal radiotherapy for non-small cell lung cancer (NSCLC), in order to explore the predictors for optimizing the treatment planning of NSCLC. Methods: From Aug 2000 to Dec 2004, 104 NSCLC patients received radiotherapy and were eligible for this study, 45 cases squamous cell carcinoma, 20 cases adenocarcinoma, 33 cases carrying with cancer cells by test and 6 case with no definitive pathologic feature.46 patients were treated with three dimensional conformal radiotherapy (3DCRT), the other 58 patients conventional radiotherapy (CRT) before later-course 3DCRT. All the patients received the prescribed dose between 60-78 Gy and the median dose 66 Gy. The correlation of the variables were evaluated by Spearman relationship analysis. The morbidity of radiation-induced esophagitis was analyzed by X 2 test. The multivariate effect on radiation-induced esophagitis was statistically processed by Logistic regression model. Results: In 104 patients, the morbidity of radiation- induced esophagitis was 46.2%, including 32 cases at grade 1, 15 cases at grade 2, 1 case at grade 3. Univariate analysis showed the maximal and mean dose of esophagus, the volume of esophagus irradiated, the values of V 40 , V 45 , V 50 , V 55 , V 60 , LETT 45 , LETT 50 , LETT 55 , LETT 60 for the esophagus were correlated with radiation-induced esophagitis. Logistic regression model showed that the maximum dose received by the esophagus was the independent factor of ≥ 2 grade radiation-induced esophagitis. Conclusions: The maxmal dose of esophagus received might be the important factor of radiation-induced esophagitis. (authors)

  2. Measurement of the three-dimensional distribution of radiation dose in grid therapy

    International Nuclear Information System (INIS)

    Trapp, J V; Warrington, A P; Partridge, M; Philps, A; Glees, J; Tait, D; Ahmed, R; Leach, M O; Webb, S

    2004-01-01

    A single large dose of megavoltage x-rays delivered through a grid is currently being utilized by some centres for palliative radiotherapy treatments of large tumours. In this note, we investigate the dosimetry of grid therapy using two-dimensional film dosimetry and three-dimensional gel dosimetry. It is shown that the radiation dose is attenuated more rapidly with depth in a grid field than an open field, and that even shielded regions receive approximately 25% of the dose to the unshielded areas. (note)

  3. Multimodal approaches including three-dimensional conformal re-irradiation for recurrent or persistent esophageal cancer. Preliminary results

    International Nuclear Information System (INIS)

    Yamaguchi, Shinsaku; Ohguri, Takayuki; Imada, Hajime

    2011-01-01

    The purpose of this study was to assess the toxicity and efficacy of multimodal approaches, including three-dimensional conformal re-irradiation, for patients with recurrent or persistent esophageal cancer after radiotherapy. Thirty-one patients with esophageal cancer treated with three-dimensional conformal re-irradiation were retrospectively analyzed. Of the 31 patients, 27 patients received concurrent chemotherapy, and 14 patients underwent regional hyperthermia during the re-irradiation. We divided the patients into two groups on the basis of their clinical condition: the curative group (n=11) or the palliative group (n=20). Severe toxicities were detected in one patient with Grade 3 esophageal perforation in the curative group, and 5 patients had a Grade 3 or higher toxicity of the esophagus in the palliative group. Advanced T stage at the time of re-irradiation was found to be significantly correlated with Grade 3 or higher toxicity in the esophagus. For the curative group, 10 (91%) of 11 patients had an objective response. For the palliative group, symptom relief was recognized in 8 (57%) of 14 patients with obvious swallowing difficulty. In conclusion, in the curative group with early-stage recurrent or persistent esophageal cancer, the multimodal approaches, including three-dimensional conformal re-irradiation, may be feasible, showing acceptable toxicity and a potential value of promising results, although further evaluations especially for the toxicities of the organs at risk are required. In the palliative group, the benefit of our therapy may be restrictive because severe esophageal toxicities were not uncommon in the patients with advanced T stage at the time of re-irradiation. (author)

  4. Dosimetry study on the conventional and three dimensional conformal radiation treatment planning protocols for rectal cancer

    International Nuclear Information System (INIS)

    Cai Yong; He Yuxiang; Han Shukui; Wu Hao; Gong Jian; Xu Bo

    2007-01-01

    Objective: To compare the dose distribution of clinical target volume (CTV), in normal tissues and organs for patients with rectal cancer on the conventional radiotherapy (2D) and three dimension- al conformal radiation treatment (3DCRT). Methods: The CT image data of 36 rectal cancer patients treated with 3DCRT were studied. The CTV, small bowel, colon, bladder, pelvic bone marrow, and femoral head and neck were contoured on consecutive axial slices of CT images. Two 3DCRT and three conventional treatment planning protocols were simulated using three dimensional treatment planning system (CMS Focus 2.31), were defined as 3D-3, 3D-4, 2D-2, 2D-3, 2D-4. The difference of five treatment planning protocols on the CTV and normal structure by analysis of dose-volume histograms (DVHs) were compared. Results: The D 95 and V 95 of these five protocols all exceeded 97%. The conformity index(CI) of 3D was obviously larger than that of 2D protocol. The dose inhomogeneity(DI) in 4 DCRT was less than that of 3 DCRT. The 3D as compared with the 2D, significantly reduced the mean dose of 45 Gy to the small bowel and colon. The 3D-3 as compared with the 2D-3, the 3D-4 as compared with the 2D-4, the mean dose of small bowel and colon was reduced by 28.5% and 25.7%, respectively. The 3D-3 as compared with the 2D-2, the 3D-3 as compared with the 2D-3 and the 3D4 as compared with the 2D-4, the percentage volume of small bowel and colon which received 45 Gy was reduced by 80.8% , 51.1% and 54.7% , respectively. Either the mean dose, or the percentage volume receiving 35 Gy and 45 Gy to the pelvic bone and bladder, the 3D planning protocols had advanage over the 2D planning protocols. The V 45 of bladder in 2D-2 planning proto- col was the highest in all planning protocols, exceeding 98%, but the highest V 45 of bladder was only 50% in the other planning protocols. Conclusions: Even though the difference in pelvic CTV of rectal cancer patients between the conventional radiotherapy and 3

  5. Significant reduction of normal tissue dose by proton radiotherapy compared with three-dimensional conformal or intensity-modulated radiation therapy in Stage I or Stage III non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Chang, Joe Y.; Zhang Xiaodong; Wang Xiaochun; Kang Yixiu; Riley, Beverly C.; Bilton, Stephen C.; Mohan, Radhe; Komaki, Ritsuko; Cox, James D.

    2006-01-01

    Purpose: To compare dose-volume histograms (DVH) in patients with non-small-cell lung cancer (NSCLC) treated by photon or proton radiotherapy. Methods and Materials: Dose-volume histograms were compared between photon, including three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and proton plans at doses of 66 Gy, 87.5 Gy in Stage I (n = 10) and 60-63 Gy, and 74 Gy in Stage III (n 15). Results: For Stage I, the mean total lung V5, V10, and V20 were 31.8%, 24.6%, and 15.8%, respectively, for photon 3D-CRT with 66 Gy, whereas they were 13.4%, 12.3%, and 10.9%, respectively, with proton with dose escalation to 87.5 cobalt Gray equivalents (CGE) (p = 0.002). For Stage III, the mean total lung V5, V10, and V20 were 54.1%, 46.9%, and 34.8%, respectively, for photon 3D-CRT with 63 Gy, whereas they were 39.7%, 36.6%, and 31.6%, respectively, for proton with dose escalation to 74 CGE (p = 0.002). In all cases, the doses to lung, spinal cord, heart, esophagus, and integral dose were lower with proton therapy even compared with IMRT. Conclusions: Proton treatment appears to reduce dose to normal tissues significantly, even with dose escalation, compared with standard-dose photon therapy, either 3D-CRT or IMRT

  6. In vivo dose estimations through transit signal measured with thimble chamber positioned along the central axis at electronic portal imaging device level in medical linear accelerator in carcinoma of the middle-third esophagus patients undergoing three-dimensional conformal radiotherapy.

    Science.gov (United States)

    Kumar, Putha Suman; Banerjee, S; Arun Kumar, E S; Srinivas, Challapalli; Vadhiraja, B M; Saxena, P U; Ravichandran, Ramamoorthy; Kasturi, Dinesh Pai

    2018-01-01

    This study presents a method to estimate midplane dose (D iso, transit ) in vivo from transit signal (S t ) measured with thimble ionization chamber in cancer of the middle-third esophagus patients treated with three-dimensional radiotherapy (RT). This detector is positioned at the level of electronic portal imaging device in the gantry of a medical linear accelerator. Efficacy of inhomogeneity corrections of three dose calculation algorithms available in XiO treatment planning system (TPS) for planned dose (for open fields) (D iso, TPS ) was studied with three heterogeneous phantoms. D iso, transit represents measured signal at transit point (S t ) far away correlating to dose at isocenter. A locally fabricated thorax phantom was used to measure the in vivo midplane dose (D iso, mid ) which was also estimated through S t . Thirteen patients with carcinoma of the middle-third esophagus treated with three-dimensional conformal RT were studied. S t was recorded (three times, with a gap of 5-6 fractions during the treatment) to estimate D iso, transit , which was compared with the doses calculated by TPS. The dose predictions by superposition algorithm were superior compared to the other algorithms. Percentage deviation of D iso, transit , D iso, mid with D iso, TPS combined all fields was 2.7 and -2.6%, respectively, with the thorax phantom. The mean percentage deviation with standard deviation of estimated D iso, transit with D iso, TPS observed in patients was within standard deviation -0.73% ±2.09% (n = 39). Midplane dose estimates in vivo using this method provide accurate determination of delivered dose in the middle-third esophagus RT treatments. This method could be useful in similar clinical circumstances for dose confirmation and documentation.

  7. Dosimetric comparison of proton and photon three-dimensional, conformal, external beam accelerated partial breast irradiation techniques

    International Nuclear Information System (INIS)

    Kozak, Kevin R.; Katz, Angela; Adams, Judith C.; Crowley, Elizabeth M.; Nyamwanda, Jacqueline A.C.; Feng, Jennifer K.C.; Doppke, Karen P.; DeLaney, Thomas F.; Taghian, Alphonse G.

    2006-01-01

    Purpose: To compare the dosimetry of proton and photon-electron three-dimensional, conformal, external beam accelerated partial breast irradiation (3D-CPBI). Methods and Materials: Twenty-four patients with fully excised, Stage I breast cancer treated with adjuvant proton 3D-CPBI had treatment plans generated using the mixed-modality, photon-electron 3D-CPBI technique. To facilitate dosimetric comparisons, planning target volumes (PTVs; lumpectomy site plus 1.5-2.0 cm margin) and prescribed dose (32 Gy) were held constant. Plans were optimized for PTV coverage and normal tissue sparing. Results: Proton and mixed-modality plans both provided acceptable PTV coverage with 95% of the PTV receiving 90% of the prescribed dose in all cases. Both techniques also provided excellent dose homogeneity with a dose maximum exceeding 110% of the prescribed dose in only one case. Proton 3D-CPBI reduced the volume of nontarget breast tissue receiving 50% of the prescribed dose by an average of 36%. Statistically significant reductions in the volume of total ipsilateral breast receiving 100%, 75%, 50%, and 25% of the prescribed dose were also observed. The use of protons resulted in small, but statistically significant, reductions in the radiation dose delivered to 5%, 10%, and 20% of ipsilateral and contralateral lung and heart. The nontarget breast tissue dosimetric advantages of proton 3D-CPBI were not dependent on tumor location, breast size, PTV size, or the ratio of PTV to breast volume. Conclusions: Compared to photon-electron 3D-CPBI, proton 3D-CPBI significantly reduces the volume of irradiated nontarget breast tissue. Both approaches to accelerated partial breast irradiation offer exceptional lung and heart sparing

  8. Three dimensional-conformal radiotherapy combined with capecitabine chemotherapy for locally advanced (unresectable) rectal cancer

    International Nuclear Information System (INIS)

    Zhu Yaqun; Tian Ye; Zhang Junning; Wang Bin

    2010-01-01

    Objective: To evaluate the compliance and efficacy of chemoradiotherapy for locally advanced (unresectable) rectal cancer. Methods: Thirty eight patients with locally advanced (T4 or recurred) rectal cancer received three dimensional-conformal radiotherapy (for 46 ∼ 50Gy/5 weeks and was boosted to the tumor 16 ∼ 18Gy/2 weeks, 2Gy/fraction, 5 days/week) in combination with capecitabine 1 650mg · m -2 · d -1 , day 1-14, every 3 weeks. Results: The overall response rate was 57.9%, with CR 5 (13.2%), PR 17(44.7%), SD 10 (26.3%), PD 6 (15.8%), median survival time, the 1-year overall survival rate and the 2-year overall survival rate were 18 months, 64.43%, 18.78%, respectively. The remission rate of pain and improvement rate of performance status were 100% and 52.8%. Treatment-related toxicity mainly showed at diarrhea, neutrocytopenia and hand-foot syndrome, the incidence of grade 3 toxicity were 15.8%, 15.8%, 7.9%, respectively. there were no grade 4 toxicity and treatment-related death. Conclusion: Combination of three dimensional-conformal radiotherapy with capecitabine is active in advanced rectal cancer, It is a well-tolerated regimen. (authors)

  9. Analysis of the efficacy and safety of conventional radiotherapy of chest wall and clavicular field and three-dimensional conformal radiotherapy in patients after modified radical mastectomy

    Directory of Open Access Journals (Sweden)

    Song-Lin Wang

    2017-04-01

    Full Text Available Objective: To explore the efficacy and safety of conventional radiotherapy of chest wall and clavicular field and three-dimensional conformal radiotherapy in patients after modified radical mastectomy. Methods: A total of 84 patients who were admitted in our hospital after modified radical mastectomy were included in the study and divided into the conventional radiotherapy group (n=42 and the three-dimensional conformal radiotherapy group (n=42 according to different radiotherapy methods. The patients in the conventional radiotherapy group were given conventional radiotherapy of chest wall and clavicular field, while the patients in the three-dimensional conformal radiotherapy group were given three-dimensional conformal radiotherapy. The serum tumor markers and peripheral blood T lymphocyte subsets 6-8 weeks after treatment in the two groups were detected. The clinical efficacy, and toxic and side effects in the two groups were evaluated. Results: The serum CA15-3, CA125, CEA, and CK19 levels after treatment in the two groups were significantly reduced when compared with before treatment, CD3 +,CD4 +, and CD4 +/CD8 + were significantly elevated, while CD8 + was significantly reduced when compared with before treatment, but the comparison of the above indicators between the two groups was not statistically significant. The occurrence rate of radioactive skin damage and pneumonia after treatment in the conventional radiotherapy group was significantly higher than that in the three-dimensional conformal radiotherapy group. Conclusions: The two kinds of radiotherapy schemes have an equal efficacy, but the toxic and side effects of three-dimensional conformal radiotherapy are significantly lower than those by the conventional radiotherapy, with a certain advantage.

  10. Fermionic field perturbations of a three-dimensional Lifshitz black hole in conformal gravity

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, P.A. [Facultad de Ingenieria y Ciencias, Universidad Diego Portales, Santiago (Chile); Vasquez, Yerko; Villalobos, Ruth Noemi [Universidad de La Serena, Departamento de Fisica y Astronomia, Facultad de Ciencias, La Serena (Chile)

    2017-09-15

    We study the propagation of massless fermionic fields in the background of a three-dimensional Lifshitz black hole, which is a solution of conformal gravity. The black-hole solution is characterized by a vanishing dynamical exponent. Then we compute analytically the quasinormal modes, the area spectrum, and the absorption cross section for fermionic fields. The analysis of the quasinormal modes shows that the fermionic perturbations are stable in this background. The area and entropy spectrum are evenly spaced. In the low frequency limit, it is observed that there is a range of values of the angular momentum of the mode that contributes to the absorption cross section, whereas it vanishes in the high frequency limit. In addition, by a suitable change of variables a gravitational soliton can also be obtained and the stability of the quasinormal modes are studied and ensured. (orig.)

  11. Conformal radiotherapy using multileaf collimation: quality assurance and in vivo dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Aletti, P [Centre A. Vautrin, Nancy (France)

    1995-12-01

    The application of quality assurance principles in three dimensional conformal therapy is discussed.Critical requirements in three dimensional radiotherapy are the patient immobilization, the location, and the delivered dose. General recommendations with respect to the equipment for conformal radiotherapy and personnel are made.

  12. Conformal radiotherapy using multileaf collimation: quality assurance and in vivo dosimetry

    International Nuclear Information System (INIS)

    Aletti, P.

    1995-01-01

    The application of quality assurance principles in three dimensional conformal therapy is discussed.Critical requirements in three dimensional radiotherapy are the patient immobilization, the location, and the delivered dose. General recommendations with respect to the equipment for conformal radiotherapy and personnel are made

  13. Method to planarize three-dimensional structures to enable conformal electrodes

    Science.gov (United States)

    Nikolic, Rebecca J; Conway, Adam M; Graff, Robert T; Reinhardt, Catherine; Voss, Lars F; Shao, Qinghui

    2012-11-20

    Methods for fabricating three-dimensional PIN structures having conformal electrodes are provided, as well as the structures themselves. The structures include a first layer and an array of pillars with cavity regions between the pillars. A first end of each pillar is in contact with the first layer. A segment is formed on the second end of each pillar. The cavity regions are filled with a fill material, which may be a functional material such as a neutron sensitive material. The fill material covers each segment. A portion of the fill material is etched back to produce an exposed portion of the segment. A first electrode is deposited onto the fill material and each exposed segment, thereby forming a conductive layer that provides a common contact to each the exposed segment. A second electrode is deposited onto the first layer.

  14. Three-dimensional (3D) real-time conformal brachytherapy - a novel solution for prostate cancer treatment Part I. Rationale and method

    International Nuclear Information System (INIS)

    Fijalkowski, M.; Bialas, B.; Maciejewski, B.; Bystrzycka, J.; Slosarek, K.

    2005-01-01

    Recently, the system for conformal real-time high-dose-rate brachytherapy has been developed and dedicated in general for the treatment of prostate cancer. The aim of this paper is to present the 3D-conformal real-time brachytherapy technique introduced to clinical practice at the Institute of Oncology in Gliwice. Equipment and technique of 3D-conformal real time brachytherapy (3D-CBRT) is presented in detail and compared with conventional high-dose-rate brachytherapy. Step-by-step procedures of treatment planning are described, including own modifications. The 3D-CBRT offers the following advantages: (1) on-line continuous visualization of the prostate and acquisition of the series of NS images during the entire procedure of planning and treatment; (2) high precision of definition and contouring the target volume and the healthy organs at risk (urethra, rectum, bladder) based on 3D transrectal continuous ultrasound images; (3) interactive on-line dose optimization with real-time corrections of the dose-volume histograms (DVHs) till optimal dose distribution is achieved; (4) possibility to overcome internal prostate motion and set-up inaccuracies by stable positioning of the prostate with needles fixed to the template; (5) significant shortening of overall treatment time; (6) cost reduction - the treatment can be provided as an outpatient procedure. The 3D- real time CBRT can be advertised as an ideal conformal boost dose technique integrated or interdigitated with pelvic conformal external beam radiotherapy or as a monotherapy for prostate cancer. (author)

  15. Preliminary results of three-dimensional conformal radiotherapy for non-small cell lung cancer

    International Nuclear Information System (INIS)

    Wang Yingjie; Wang Luhua; Wang Xin; Feng Qinfu; Zhang Hongxing; Xiao Zefen; Yin Weibo

    2005-01-01

    Objective: To evaluate the therapeutic effects and complications of three-dimensional conformal radiotherapy (3DCRT) for non-small cell lung cancer (NSCLC). Methods: Between March 1999 and September 2003, 91 NSCLC patients treated with 3DCRT were reviewed at the Cancer Hospital, Chinese Academy of Medical Sciences. This patient cohort consisted of 73 men and 18 women. The median age was 66 years. Radio-therapy was delivered at 2 Gy fraction, 5 fractions per week. The median total dose was 60 Gy. Results: With a median follow-up time of 17 months, the response rate after 3DCRT was 57.1%, with complete remission 11.0% (10/91) and partial remission 46.2%(42/91). The median survival time (MST) was 16 months, with 1- and 2- year overall survivals (OS) of 67.0% and 32.6%, 1- and 2-year local progression free survivals (LPFS) of 82.6% and 53.0%, respectively. The independent adverse prognostic factors by univariate analysis and multivariate analysis was weight loss ≥5%. Grade 2 acute radiation pneumonitis was observed in 2 patients and grade 3 in 4 patients. Late lung injury developed in 1 patient with grade 2, 1 patient with grade 3, respectively. Acute radiation esophagitis was observed in 8 patients with grade 2. Acute grade 2 hematologic toxicity developed in 5 patients. Conclusions: 3DCRT was feasible in the treatment of NSCLC with good immediate tumor response and acceptable normal tissue complication. The total dose may potentially be increased. (authors)

  16. Australian and New Zealand three-dimensional conformal radiation therapy consensus guidelines for prostate cancer

    International Nuclear Information System (INIS)

    Skala, M.; Berry, M.; Kneebone, A.; Gogna, K.; Turner, S.; Rolfo, A.; Haworth, A.

    2004-01-01

    Three-dimensional conformal radiation therapy (3DCRT) has been shown to reduce normal tissue toxicity and allow dose escalation in the curative treatment of prostate cancer. The Faculty of Radiation Oncology Genito-Urinary Group initiated a consensus process to generate evidence-based guidelines for the safe and effective implementation of 3DCRT. All radiation oncology departments in Australia and New Zealand were invited to complete a survey of their prostate practice and to send representatives to a consensus workshop. After a review of the evidence, key issues were identified and debated. If agreement was not reached, working parties were formed to make recommendations. Draft guidelines were circulated to workshop participants for approval prior to publication. Where possible, evidence-based recommendations have been made with regard to patient selection, risk stratification, simulation, planning, treatment delivery and toxicity reporting. This is the first time a group of radiation therapists, physicists and oncologists representing professional radiotherapy practice across Australia and New Zealand have worked together to develop best-practice guidelines. These guidelines should serve as a baseline for prospective clinical trials, outcome research and quality assurance. Copyright (2004) Blackwell Science Pty Ltd

  17. Three-Dimensional Conformal Radiation Therapy and Intensity-Modulated Radiation Therapy Combined With Transcatheter Arterial Chemoembolization for Locally Advanced Hepatocellular Carcinoma: An Irradiation Dose Escalation Study

    International Nuclear Information System (INIS)

    Ren Zhigang; Zhao Jiandong; Gu Ke; Chen Zhen; Lin Junhua; Xu Zhiyong; Hu Weigang; Zhou Zhenhua; Liu Luming; Jiang Guoliang

    2011-01-01

    Purpose: To determine the maximum tolerated dose (MTD) of three-dimensional conformal radiation therapy (3DCRT)/intensity-modulated radiation therapy (IMRT) combined with transcatheter arterial chemoembolization for locally advanced hepatocellular carcinoma. Methods and Materials: Patients were assigned to two subgroups based on tumor diameter: Group 1 had tumors <10 cm; Group II had tumors ≥10 cm. Escalation was achieved by increments of 4.0 Gy for each cohort in both groups. Dose-limiting toxicity (DLT) was defined as a grade of ≥3 acute liver or gastrointestinal toxicity or any grade 5 acute toxicity in other organs at risk or radiation-induced liver disease. The dose escalation would be terminated when ≥2 of 8 patients in a cohort experienced DLT. Results: From April 2005 to May 2008, 40 patients were enrolled. In Group I, 11 patients had grade ≤2 acute treatment-related toxicities, and no patient experienced DLT; and in Group II, 10 patients had grade ≤2 acute toxicity, and 1 patient in the group receiving 52 Gy developed radiation-induced liver disease. MTD was 62 Gy for Group I and 52 Gy for Group II. In-field progression-free and local progression-free rates were 100% and 69% at 1 year, and 93% and 44% at 2 years, respectively. Distant metastasis rates were 6% at 1 year and 15% at 2 years. Overall survival rates for 1-year and 2-years were 72% and 62%, respectively. Conclusions: The irradiation dose was safely escalated in hepatocellular carcinoma patients by using 3DCRT/IMRT with an active breathing coordinator. MTD was 62 Gy and 52 Gy for patients with tumor diameters of <10 cm and ≥10 cm, respectively.

  18. Three-dimensional absorbed dose determinations by N.M.R. analysis of phantom-dosemeters

    International Nuclear Information System (INIS)

    Gambarini, G.; Birattari, C.; Fumagalli, M.L.; Vai, A.; Monti, D.; Salvadori, P.; Facchielli, L.; Sichirollo, A.E.

    1996-01-01

    Magnetic resonance imaging of a tissue-equivalent phantom is a promising technique for three-dimensional determination of absorbed dose from ionizing radiation. A reliable method of determining the spatial distribution of absorbed dose is indispensable for the planning of treatment in the presently developed radiotherapy techniques aimed at obtaining high energy selectively delivered to cancerous tissues, with low dose delivered to the surrounding healthy tissue. Aqueous gels infused with the Fricke dosemeter (i.e. with a ferrous sulphate solution), as proposed in 1984 by Gore et al., have shown interesting characteristics and, in spite of some drawbacks that cause a few limitations to their utilisation, they have shown the feasibility of three-dimensional dose determinations by nuclear magnetic resonance (NMR) imaging. Fricke-infused agarose gels with various compositions have been analysed, considering the requirements of the new radiotherapy techniques, in particular Boron Neutron Capture Therapy (B.N.C.T.) and proton therapy. Special attention was paid to obtain good tissue equivalence for every radiation type of interest. In particular, the tissue equivalence for thermal neutrons, which is a not simple problem, has also been satisfactorily attained. The responses of gel-dosemeters having the various chosen compositions have been analysed, by mean of NMR instrumentation. Spectrophotometric measurements have also been performed, to verify the consistence of the results. (author)

  19. Setup error in three-dimensional conformal radiotherapy for thoracic esophageal carcinoma

    International Nuclear Information System (INIS)

    Hong Jinsheng; Zhang Weijian; Chen Jinmei; Cai Chuanshu; Ke Chunlin; Chen Xiuying; Wu Bing; Guo Feibao

    2009-01-01

    Objective: To study the setup errors in three-dimensional conformal radiotherapy (3DCRT) for thoracic esophageal carcinoma using electronic portal imaging device(EPID) and calculate the margins from CTV to PTV. Methods: Forty-one patients with thoracic esophageal carcinoma who received 3DCRT were continuously enrolled into this study. The anterior and lateral electronic portal images (EPI) were aquired by EPID once a week. The setup errors were obtained through comparing the difference between EPI and digitally reconstructed radiographs (DRR). Then the setup margins from CTV to PTV were calculated. By using self paired design, 22 patients received definitive radiotherapy with different margins. Group A: the margins were 10 mm in all the three axes; Group B: the margins were aquired in this study. The difference were compared by Paired t-test or Wilcoxon signed-rank test. Results: The margins from CTV to PTV in x, y and z axes were 8.72 mm, 10.50 mm and 5.62 mm, respectively. Between the group A and group B, the difference of the maximum dose of the spinal cord was significant(4638.7 cGy ± 1449.6 cGy vs. 4310.2 cGy ± 1528.7 cGy; t=5.48, P=0.000), and the difference of NTCP for the spinal cord was also significant (4.82% ± 5.99% vs. 3.64% ± 4.70%; Z=-2.70, P=0.007). Conclusions: For patients with thoracic esophageal carcinoma who receive 3DCRT in author's department, the margins from CTV to PTV in x, y and z axes were 8.72 mm, 10.50 mm and 5.62 mm, respectively. The spinal cord could be better protected by using these setup margins than using 10 mm in each axis. (authors)

  20. Intensity-modulated three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Mohan, Radhe

    1996-01-01

    Optimized intensity-modulated treatments one of the important advances in photon radiotherapy. Intensity modulation provides a greatly increased control over dose distributions. Such control can be maximally exploited to achieve significantly higher levels of conformation to the desired clinical objectives using sophisticated optimization techniques. Safe, rapid and efficient delivery of intensity-modulated treatments has become feasible using a dynamic multi-leaf collimator under computer control. The need for all other field shaping devices such as blocks, wedges and compensators is eliminated. Planning and delivery of intensity-modulated treatments is amenable to automation and development of class solutions for each treatment site and stage which can be implemented not only at major academic centers but on a wide scale. A typical treatment involving as many as 10 fields can be delivered in times shorter than much simpler conventional treatments. The main objective of the course is to give an overview of the current state of the art of planning and delivery methods of intensity-modulated treatments. Specifically, the following topics will be covered using representative optimized plans and treatments: 1. A typical procedure for planning and delivering an intensity-modulated treatment. 2. Quantitative definition of criteria (i.e., the objective function) of optimization of intensity-modulated treatments. Clinical relevance of objectives and the dependence of the quality of optimized intensity-modulated plans upon whether the objectives are stated purely in terms of simple dose or dose-volume criteria or whether they incorporate biological indices. 3. Importance of the lateral transport of radiation in the design of intensity-modulated treatments. Impact on dose homogeneity and the optimum choice of margins. 4. Use of intensity-modulated treatments in escalation of tumor dose for the same or lower normal tissue dose. Fractionation of intensity-modulated treatments

  1. Intensity-modulated three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Mohan, Radhe

    1997-01-01

    Optimized intensity-modulated treatments one of the important advances in photon radiotherapy. Intensity modulation provides a greatly increased control over dose distributions. Such control can be maximally exploited to achieve significantly higher levels of conformation to the desired clinical objectives using sophisticated optimization techniques. Safe, rapid and efficient delivery of intensity-modulated treatments has become feasible using a dynamic multi-leaf collimator under computer control. The need for all other field shaping devices such as blocks, wedges and compensators is eliminated. Planning and delivery of intensity-modulated treatments is amenable to automation and development of class solutions for each treatment site and stage which can be implemented not only at major academic centers but on a wide scale. A typical treatment involving as many as 10 fields can be delivered in times shorter than much simpler conventional treatments. The main objective of the course is to give an overview of the current state of the art of planning and delivery methods of intensity-modulated treatments. Specifically, the following topics will be covered using representative optimized plans and treatments: 1. A typical procedure for planning and delivering an intensity-modulated treatment. 2. Quantitative definition of criteria (i.e., the objective function) of optimization of intensity-modulated treatments. Clinical relevance of objectives and the dependence of the quality of optimized intensity-modulated plans upon whether the objectives are stated purely in terms of simple dose or dose-volume criteria or whether they incorporate biological indices. 3. Importance of the lateral transport of radiation in the design of intensity-modulated treatments. Impact on dose homogeneity and the optimum choice of margins. 4. Use of intensity-modulated treatments in escalation of tumor dose for the same or lower normal tissue dose. Fractionation of intensity-modulated treatments

  2. CT-image based conformal high-dose rate brachytherapy boost in the conservative treatment of stage I - II breast cancer - introducing the procedure

    International Nuclear Information System (INIS)

    Kubaszewska, M.; Skowronek, J.; Chichel, A.; Kanikowski, M.; Dymnicka, M.

    2008-01-01

    Aim: Breast-conserving surgery (BCS) followed by radiotherapy (RT) has become the standard treatment for the majority of patients with early breast cancer. With regard to boost technique some disagreements are found between groups that are emphasizing the value of electron boost treatment and groups pointing out the value of interstitial brachytherapy (BT) boost treatment. We present the preliminary results in treating selected patients with early-stage breast cancer using high-dose-rate brachytherapy (HD R-BT) as a boost after breast conservation therapy (BCT). Materials/Methods: Between January 2006 and August 2007, a total of 58 female patients with first and second stage breast cancer underwent BCT. This therapeutic procedure involves BCS, whole breast radiation therapy (WBRT) and additional irradiation to the tumour bed (boost) using interstitial HDR-BT via flexible implant tubes. A 10 Gy boost dose was received by all patients. The treatment planning was based on CT-guided 3D (three-dimensional) reconstruction of the surgical clips, implant tubes and critical structures localization (skin and ribs). The accuracy of tumour bed localization, the conformity of planning target volume and treated volume were analyzed. Results: The evaluations of implant parameters involved the use of: dose volume histogram (DVH), the volume encompassed by the 100% reference isodose surface (V100%), the high dose volumecalculation (V150%, V200%, V300%), the dose non-uniformity ratio (DNR), and the conformity index (COIN). Our results were as follows: the mean PTV volume, the mean high dose volume (V150%; V200%; V300%), the DNR and COIN mean value were estimated at 57.38, 42.98, 21.38, 7.90, 0.52 and 0.83 respectively. Conclusions: CT-guided 3D HDR-BT is most appropriate for planning the boost procedure after BT especially in large breast volume, in cases with a deep seated tumour bed, as well as in patients with high risk for local recurrences. This technique reduces the

  3. A high-precision system for conformal intracranial radiotherapy

    International Nuclear Information System (INIS)

    Tome, Wolfgang A.; Meeks, Sanford L.; Buatti, John M.; Bova, Francis J.; Friedman, William A.; Li Zuofeng

    2000-01-01

    Purpose: Currently, optimally precise delivery of intracranial radiotherapy is possible with stereotactic radiosurgery and fractionated stereotactic radiotherapy. We report on an optimally precise optically guided system for three-dimensional (3D) conformal radiotherapy using multiple noncoplanar fixed fields. Methods and Materials: The optically guided system detects infrared light emitting diodes (IRLEDs) attached to a custom bite plate linked to the patient's maxillary dentition. The IRLEDs are monitored by a commercially available stereo camera system, which is interfaced to a personal computer. An IRLED reference is established with the patient at the selected stereotactic isocenter, and the computer reports the patient's current position based on the location of the IRLEDs relative to this reference position. Using this readout from the computer, the patient may be dialed directly to the desired position in stereotactic space. The patient is localized on the first day and a reference file is established for 5 different couch positions. The patient's image data are then imported into a commercial convolution-based 3D radiotherapy planning system. The previously established isocenter and couch positions are then used as a template upon which to design a conformal 3D plan with maximum beam separation. Results: The use of the optically guided system in conjunction with noncoplanar radiotherapy treatment planning using fixed fields allows the generation of highly conformal treatment plans that exhibit a high degree of dose homogeneity and a steep dose gradient. To date, this approach has been used to treat 28 patients. Conclusion: Because IRLED technology improves the accuracy of patient localization relative to the linac isocenter and allows real-time monitoring of patient position, one can choose treatment-field margins that only account for beam penumbra and image resolution without adding margin to account for larger and poorly defined setup uncertainty. This

  4. Topics in two dimensional conformal field theory and three dimensional topological lattice field theory

    International Nuclear Information System (INIS)

    Chung, Stephen-wei.

    1993-01-01

    The authors first construct new parafermions in two-dimensional conformal field theory, generalizing the Z L parafermion theories from integer L to rational L. These non-unitary parafermions have some novel features: an infinite number of currents with negative conformal dimensions for most (if not all) of them. String functions of these new parafermion theories are calculated. They also construct new representations of N = 2 superconformal field theories, whose characters are obtained in terms of these new string functions. They then generalize Felder's BRST cohomology method to construct the characters and branching functions of the SU(2) L x SU(2) K /SU(2) K+L coset theories, where one of the (K,L) is an integer. This method of obtaining the branching functions also serves as a check of their new Z L parafermion theories. The next topic is the Lagrangian formulation of conformal field theory. They construct a chiral gauged WZW theory where the gauge fields are chiral and belong to the subgroups H L and H R , which can be different groups. This new construction is beyond the ordinary vector gauged WZW theory, whose gauge group H is a subgroup of both G L and G R . In the special case where H L = H R , the quantum theory of chiral gauged WZW theory is equivalent to that of the vector gauged WZW theory. It can be further shown that the chiral gauged WZW theory is equivalent to [G L /H L ](z) direct-product [G R /H R ](bar z) coset models in conformal field theory. In the second half of this thesis, they construct topological lattice field theories in three dimensions. After defining a general class of local lattice field theories, they impose invariance under arbitrary topology-preserving deformations of the underlying lattice, which are generated by two local lattice moves. Invariant solutions are in one-to-one correspondence with Hopf algebras satisfying a certain constraint

  5. Erectile dysfunction after prostate three-dimensional conformal radiation therapy. Correlation with the dose to the penile bulb

    International Nuclear Information System (INIS)

    Magli, A.; Ceschia, T.; Titone, F.; Parisi, G.; Fongione, S.; Giangreco, M.; Crespi, M.; Negri, A.; De Giorgi, G.

    2012-01-01

    Purpose: Erectile dysfunction is associated with all the common treatment options for prostate cancer. The aim of this research was to evaluate the relationship between erectile function and radiation dose to the penile bulb (PB) and other proximal penile structures in men receiving conformal radiotherapy (CRT) without hormonal therapy (HT) for prostate cancer, whose sexual function was known before treatment. Patients and methods: The study included 19 patients treated with 3D-CRT for localized prostate cancer at our department, who were self-reported to be potent before treatment, had not received HT, and had complete follow-up data available. Our evaluation was based on the International Index of Erectile Function (IIEF-5). Dose-volume histograms (DVHs) were used to evaluate the dose to the PB. Statistical analysis was performed with an unconditional logistic regression model. Results: All patients reported change in potency after radiation. Eight patients (42%) remained potent but showed a decrease of 1 or 2 levels of potency, as defined by the IIEF-5 questionnaire (reduced potency group), while 11 patients (58%) reported a change of higher levels and revealed a severe erectile dysfunction after 2 years (impotence group). Multivariate analysis of morphological and dosimetric variables yielded significance for the mean dose (p = 0.05 with an odds ratio of 1.14 and 95% CI 1-1.30). Patients receiving a mean dose of less than 50 Gy to the PB appear to have a much greater likelihood of maintaining potency. Conclusion: Our data suggest a possible existence of a dose-volume correlation between the dose applied to the PB and radiation-induced impotence. (orig.)

  6. Erectile dysfunction after prostate three-dimensional conformal radiation therapy. Correlation with the dose to the penile bulb

    Energy Technology Data Exchange (ETDEWEB)

    Magli, A.; Ceschia, T.; Titone, F.; Parisi, G.; Fongione, S. [University Hospital Udine (Italy). Dept. of Radiation Oncology; Giangreco, M. [Udine Univ. (Italy). Hygiene and Epidemiology Inst.; Crespi, M.; Negri, A. [University Hospital Udine (Italy). Dept. of Medical Physics; De Giorgi, G. [University Hospital Udine (Italy). Dept. of Urology

    2012-11-15

    Purpose: Erectile dysfunction is associated with all the common treatment options for prostate cancer. The aim of this research was to evaluate the relationship between erectile function and radiation dose to the penile bulb (PB) and other proximal penile structures in men receiving conformal radiotherapy (CRT) without hormonal therapy (HT) for prostate cancer, whose sexual function was known before treatment. Patients and methods: The study included 19 patients treated with 3D-CRT for localized prostate cancer at our department, who were self-reported to be potent before treatment, had not received HT, and had complete follow-up data available. Our evaluation was based on the International Index of Erectile Function (IIEF-5). Dose-volume histograms (DVHs) were used to evaluate the dose to the PB. Statistical analysis was performed with an unconditional logistic regression model. Results: All patients reported change in potency after radiation. Eight patients (42%) remained potent but showed a decrease of 1 or 2 levels of potency, as defined by the IIEF-5 questionnaire (reduced potency group), while 11 patients (58%) reported a change of higher levels and revealed a severe erectile dysfunction after 2 years (impotence group). Multivariate analysis of morphological and dosimetric variables yielded significance for the mean dose (p = 0.05 with an odds ratio of 1.14 and 95% CI 1-1.30). Patients receiving a mean dose of less than 50 Gy to the PB appear to have a much greater likelihood of maintaining potency. Conclusion: Our data suggest a possible existence of a dose-volume correlation between the dose applied to the PB and radiation-induced impotence. (orig.)

  7. Phase II study of radiotherapy with three-dimensional conformal boost concurrent with paclitaxel and cisplatin for Stage IIIB non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Kim, Young Seok; Yoon, Sang Min; Choi, Eun Kyung; Yi, Byong Yong; Kim, Jong Hoon; Ahn, Seung Do; Lee, Sang-wook; Shin, Seong Soo; Lee, Jung Shin; Suh, Cheolwon; Kim, Sang-We; Kim, Dong Soon; Kim, Woo Sung; Park, Heon Joo; Park, Charn Il

    2005-01-01

    Purpose: To evaluate the efficacy and toxicity of concurrent chemoradiotherapy with paclitaxel/cisplatin for Stage IIIB locally advanced non-small-cell lung cancer (NSCLC). Methods and Materials: Radiotherapy was administered to a total dose of 70.2 Gy (daily fraction of 1.8 Gy, 5 days/wk), over an 8-week period, combined with chemotherapy. The chemotherapy consisted of weekly 40 mg/m 2 of paclitaxel plus 20 mg/m 2 of cisplatin for 8 consecutive weeks. All patients received three-dimensional conformal radiotherapy (3D-CRT), based on computed tomography simulated planning after 41.4 Gy. The median follow-up period of survivors was 24 months. Results: Between January 2000 and October 2002, 135 patients with a median age of 60 years were enrolled and analyzed in this prospective trial. The overall response rate was 75% including 2 cases of complete response. The major patterns of failure were local failure and distant metastasis. The 2-year overall and progression-free survival rates were 37% and 18%, respectively. The median overall and progression-free survival times were 17 months and 9 months, respectively. Hematologic toxicity >Grade 2 was observed in 19% of patients and severe non-hematologic toxicity was infrequent. Conclusions: Three-dimensional conformal radiotherapy, combined with paclitaxel and cisplatin chemotherapy, was associated with a satisfactory outcome with manageable toxicity. Further investigations are needed to improve the local control

  8. Use of benchmark dose-volume histograms for selection of the optimal technique between three-dimensional conformal radiation therapy and intensity-modulated radiation therapy in prostate cancer

    International Nuclear Information System (INIS)

    Luo Chunhui; Yang, Claus Chunli; Narayan, Samir; Stern, Robin L.; Perks, Julian; Goldberg, Zelanna; Ryu, Janice; Purdy, James A.; Vijayakumar, Srinivasan

    2006-01-01

    Purpose: The aim of this study was to develop and validate our own benchmark dose-volume histograms (DVHs) of bladder and rectum for both conventional three-dimensional conformal radiation therapy (3D-CRT) and intensity-modulated radiation therapy (IMRT), and to evaluate quantitatively the benefits of using IMRT vs. 3D-CRT in treating localized prostate cancer. Methods and Materials: During the implementation of IMRT for prostate cancer, our policy was to plan each patient with both 3D-CRT and IMRT. This study included 31 patients with T1b to T2c localized prostate cancer, for whom we completed double-planning using both 3D-CRT and IMRT techniques. The target volumes included prostate, either with or without proximal seminal vesicles. Bladder and rectum DVH data were summarized to obtain an average DVH for each technique and then compared using two-tailed paired t test analysis. Results: For 3D-CRT our bladder doses were as follows: mean 28.8 Gy, v60 16.4%, v70 10.9%; rectal doses were: mean 39.3 Gy, v60 21.8%, v70 13.6%. IMRT plans resulted in similar mean dose values: bladder 26.4 Gy, rectum 34.9 Gy, but lower values of v70 for the bladder (7.8%) and rectum (9.3%). These benchmark DVHs have resulted in a critical evaluation of our 3D-CRT techniques over time. Conclusion: Our institution has developed benchmark DVHs for bladder and rectum based on our clinical experience with 3D-CRT and IMRT. We use these standards as well as differences in individual cases to make decisions on whether patients may benefit from IMRT treatment rather than 3D-CRT

  9. Hyperfractionated conformal radiotherapy in locally advanced prostate cancer: results of a dose escalation study

    International Nuclear Information System (INIS)

    Forman, Jeffrey D.; Duclos, Marie; Shamsa, Falah; Porter, Arthur T.; Orton, Colin

    1996-01-01

    Purpose: This study was initiated to assess the incidence of chronic complications and histologic and biochemical control following hyperfractionated conformal radiotherapy in patients with locally advanced prostate cancer. Methods and Materials: Between October 1991 and October 1994, 49 patients with locally advanced prostate cancer were entered on the first two dose levels of a prospective dose-escalation study using hyperfractionated three dimensional conformal radiotherapy. The first 25 patients received a minimum tumor dose of 78 Gy to the prostate and seminal vesicles in 6 weeks at 1.3 Gy, b.i.d. No increase in chronic toxicity compared with conventional radiotherapy was noted; therefore, an additional 24 patients were treated to a minimum tumor dose of 82.8 Gy to the prostate and seminal vesicles in 7 weeks at 1.15 Gy, b.i.d. Toxicity was scored according to the Radiation Therapy Oncology Group morbidity grading scale. Efficacy was assessed through scheduled postradiation prostate specific antigen values and ultrasound-guided biopsies. The median follow-up for the entire group was 20 months. Results: The hyperfractionated external radiation was well tolerated with minimal acute morbidity. At 30 months, the actuarial probability of Grade 2 gastrointestinal toxicity was 17%. At 30 months, the actuarial probability of Grade 2 genitourinary toxicity was 16%. There was no statistically significant difference between the two dose levels. No Grade 3 or 4 gastrointestinal or genitourinary toxicity was noted. At 12 months, 84% of patients had a prostate specific antigen ≤ 4; and 53%; ≤ 1 ng/ml. At 12 months, 71% of patients had post radiation biopsies that were either negative (55%) or showed a marked therapeutic effect (16%). Conclusion: The use of hyperfractionated conformal radiotherapy facilitated dose escalation with no increase in chronic toxicity compared to standard doses. The initial tumor response based on prostate specific antigen measurements and

  10. Comparing two strategies of dynamic intensity modulated radiation therapy (dIMRT with 3-dimensional conformal radiation therapy (3DCRT in the hypofractionated treatment of high-risk prostate cancer

    Directory of Open Access Journals (Sweden)

    Yartsev Slav

    2008-01-01

    Full Text Available Abstract Background To compare two strategies of dynamic intensity modulated radiation therapy (dIMRT with 3-dimensional conformal radiation therapy (3DCRT in the setting of hypofractionated high-risk prostate cancer treatment. Methods 3DCRT and dIMRT/Helical Tomotherapy(HT planning with 10 CT datasets was undertaken to deliver 68 Gy in 25 fractions (prostate and simultaneously delivering 45 Gy in 25 fractions (pelvic lymph node targets in a single phase. The paradigms of pelvic vessel targeting (iliac vessels with margin are used to target pelvic nodes and conformal normal tissue avoidance (treated soft tissues of the pelvis while limiting dose to identified pelvic critical structures were assessed compared to 3DCRT controls. Both dIMRT/HT and 3DCRT solutions were compared to each other using repeated measures ANOVA and post-hoc paired t-tests. Results When compared to conformal pelvic vessel targeting, conformal normal tissue avoidance delivered more homogenous PTV delivery (2/2 t-test comparisons; p dose, 1–3 Gy over 5/10 dose points; p Conclusion dIMRT/HT nodal and pelvic targeting is superior to 3DCRT in dose delivery and critical structure sparing in the setting of hypofractionation for high-risk prostate cancer. The pelvic targeting paradigm is a potential solution to deliver highly conformal pelvic radiation treatment in the setting of nodal location uncertainty in prostate cancer and other pelvic malignancies.

  11. Comparison of Patient Dose in Two-Dimensional Carotid Arteriography and Three-Dimensional Rotational Angiography

    International Nuclear Information System (INIS)

    Tsapaki, Virginia; Vano, Eliseo; Mavrikou, Irini; Neofotistou, Vassiliki; Gallego, Juan Jose; Fernandez, Jose Miguel; Santos, Ernesto; Mendez, Jose

    2008-01-01

    Background and Purpose. It is known that interventional neuroradiology (IN) involves high radiation dose to both patients and staff even if performed by trained operators using modern fluoroscopic X-ray equipment and dose-reducing technology. Therefore, every new technology or imaging tool introduced, such as three-dimensional rotational angiography (3D RA), should be evaluated in terms of radiation dose. 3D RA requires a series with a large number of images in comparison with 2D angiography and it is sometimes considered a high-dose IN procedure. The literature is scarce on the 3D RA radiation dose and in particular there are no data on carotid arteriography (CA). The aim of this study was to investigate patient dose differences between 2D and 3D CA. Methods. The study included 35 patients undergoing 2D CA in hospital 1 and 25 patients undergoing 3D CA in hospital 2. Patient technical data collection included information on the kerma area product (KAP), fluoroscopy time (T), total number of series (S), and total number of acquired images (F). Results. Median KAP was 112 Gy cm 2 and 41 Gy cm 2 for hospitals 1 and 2, respectively, median T was 8.2 min and 5.1 min, median S was 13 and 4, and median F was 247 and 242. Entrance surface air-kerma rate, as measured in 'medium' fluoroscopy mode measured in 2D acquisition using a 20 cm phantom of polymethylmethacrylate, was 17.3 mGy/min for hospital 1 and 9.2 mGy/min for hospital 2. Conclusion. 3D CA allows a substantial reduction in patient radiation dose compared with 2D CA, while providing the necessary diagnostic information

  12. Independent dose calculation of the Tps Iplan in radiotherapy conformed with MLC

    International Nuclear Information System (INIS)

    Adrada, A.; Tello, Z.; Medina, L.; Garrigo, E.; Venencia, D.

    2014-08-01

    The systems utilization of independent dose calculation in three dimensional-Conformal Radiation Therapy (3D-Crt) treatments allows a direct verification of the treatments times. The utilization of these systems allows diminishing the probability of errors occurrence generated by the treatment planning system (Tps), allowing a detailed analysis of the dose to delivering and review of the normalization point (Np) or prescription. The independent dose calculation is realized across the knowledge of dosimetric parameters of the treatment machine and particular characteristics of every individual field. The aim of this work is develops a calculation system of punctual doses for isocentric fields conformed with multi-leaf collimation systems (MLC), where the dose calculation is in conformity with the suggested ones by ICRU Report No. 42, 1987. Calculation software was realized in C ++ under a free platform of programming (Code::Blocks). The system uses files in format Rtp, exported from the Tps to systems of record and verification (Lantis). This file contains detailed information of the dose, Um, position of the MLC sheets and collimators for every field of treatment. The size of equivalent field is obtained from the positions of every sheet; the effective depth of calculation can be introduced from the dosimetric report of the Tps or automatically from the DFS of the field. The 3D coordinates of the isocenter and the Np for the treatment plan must be introduced manually. From this information the system looks the dosimetric parameters and calculates the Um. The calculations were realized in two accelerators a NOVALIS Tx (Varian) with 120 sheets of high definition (hd-MLC) and a PRIMUS Optifocus (Siemens) with 82 sheets. 705 patients were analyzed for a total of 1082, in plans made for both equipment s, the average uncertainty with regard to the calculation of the Tps is-0.43% ± 2.42% in a range between [-7.90 %, 7.50 %]. The major uncertainty was in Np near of the

  13. Three dimensional conformal radiotherapy for the treatment of prostate cancer: low risk of chronic rectal morbidity observed in a large series of patients

    International Nuclear Information System (INIS)

    Sandler, Howard M.; McLaughlin, P. William; Ten Haken, Randall K.; Addison, Heather; Forman, Jeffrey; Lichter, Allen

    1995-01-01

    Purpose: Three dimensional conformal radiotherapy (3D CRT) may provide a technique to increase the dose delivered to target tissues while sparing uninvolved normal structures. To evaluate the role of 3D treatment in reducing the treatment toxicity, we analyzed the chronic rectal morbidity observed in a large group of patients undergoing radiotherapy for prostate cancer. Methods and Materials: From 1987 through 1992, 721 prostate cancer patients were treated with 3D CRT at the University of Michigan or Providence Hospital. All had axial computed tomography (CT) specifically for RT planning, multiple structures contoured on the axial images, and beam's-eye-view conformal beams edited to provide 3D dose coverage. Using current American Joint Commission (AJCC) staging, 537 patients had T1-T2 tumors, 123 had T3-T4 tumors, and 60 were treated postprostatectomy. Pelvic lymph nodes were treated in 462 patients. Prostate boosts were delivered with four-field axial, six-field axial, or four-field oblique, nonaxial fields. The median dose was 68.40 Gy (range 59.4-80.4). Median follow-up was 20.4 months; 175 were followed more than 3 years. All complications have been graded conservatively using the RTOG system. Results: Using a Cox proportional hazard's model, patient age, T-stage, prescribed dose, pelvic treatment, and boost technique were analyzed. The factor most strongly related to risk of morbidity was dose (p = 0.05); however, the boost technique was also related: the four-field oblique field had the lowest relative risk. Most episodes of rectal morbidity have been mild: 82 Grade 1 or 2. There have been only 14 more serious complications including 12 Grade 3 and 2 Grade 4. The actuarial risk of a Grade 3 or 4 complication is 3% at 3 and 5 years. Conclusions: A very small proportion of patients treated with 3D CRT had significant rectal morbidity related to RT, supporting the use of conformal treatment planning and dose delivery as a mechanism to minimize complications

  14. A Dosimetric Comparison of Accelerated Partial Breast Irradiation Techniques: Multicatheter Interstitial Brachytherapy, Three-Dimensional Conformal Radiotherapy, and Supine Versus Prone Helical Tomotherapy

    International Nuclear Information System (INIS)

    Patel, Rakesh R.; Becker, Stewart J.; Das, Rupak K.; Mackie, Thomas R.

    2007-01-01

    Purpose: To compare dosimetrically four different techniques of accelerated partial breast irradiation (APBI) in the same patient. Methods and Materials: Thirteen post-lumpectomy interstitial brachytherapy (IB) patients underwent imaging with preimplant computed tomography (CT) in the prone and supine position. These CT scans were then used to generate three-dimensional conformal radiotherapy (3D-CRT) and prone and supine helical tomotherapy (PT and ST, respectively) APBI plans and compared with the treated IB plans. Dose-volume histogram analysis and the mean dose (NTD mean ) values were compared. Results: Planning target volume coverage was excellent for all methods. Statistical significance was considered to be a p value mean dose of 1.3 Gy 3 and 1.2 Gy 3 , respectively. Both of these methods were statistically significantly lower than the supine external beam techniques. Overall, all four methods yielded similar low doses to the heart. Conclusions: The use of IB and PT resulted in greater normal tissue sparing (especially ipsilateral breast and lung) than the use of supine external beam techniques of 3D-CRT or ST. However, the choice of APBI technique must be tailored to the patient's anatomy, lumpectomy cavity location, and overall treatment goals

  15. Comparing two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the hypofractionated treatment of high-risk prostate cancer

    International Nuclear Information System (INIS)

    Yuen, Jasper; Rodrigues, George; Trenka, Kristina; Coad, Terry; Yartsev, Slav; D'Souza, David; Lock, Michael; Bauman, Glenn

    2008-01-01

    To compare two strategies of dynamic intensity modulated radiation therapy (dIMRT) with 3-dimensional conformal radiation therapy (3DCRT) in the setting of hypofractionated high-risk prostate cancer treatment. 3DCRT and dIMRT/Helical Tomotherapy(HT) planning with 10 CT datasets was undertaken to deliver 68 Gy in 25 fractions (prostate) and simultaneously delivering 45 Gy in 25 fractions (pelvic lymph node targets) in a single phase. The paradigms of pelvic vessel targeting (iliac vessels with margin are used to target pelvic nodes) and conformal normal tissue avoidance (treated soft tissues of the pelvis while limiting dose to identified pelvic critical structures) were assessed compared to 3DCRT controls. Both dIMRT/HT and 3DCRT solutions were compared to each other using repeated measures ANOVA and post-hoc paired t-tests. When compared to conformal pelvic vessel targeting, conformal normal tissue avoidance delivered more homogenous PTV delivery (2/2 t-test comparisons; p < 0.001), similar nodal coverage (8/8 t-test comparisons; p = ns), higher and more homogenous pelvic tissue dose (6/6 t-test comparisons; p < 0.03), at the cost of slightly higher critical structure dose (D dose , 1–3 Gy over 5/10 dose points; p < 0.03). The dIMRT/HT approaches were superior to 3DCRT in sparing organs at risk (22/24 t-test comparisons; p < 0.05). dIMRT/HT nodal and pelvic targeting is superior to 3DCRT in dose delivery and critical structure sparing in the setting of hypofractionation for high-risk prostate cancer. The pelvic targeting paradigm is a potential solution to deliver highly conformal pelvic radiation treatment in the setting of nodal location uncertainty in prostate cancer and other pelvic malignancies

  16. Rectal dose sparing with a balloon catheter and ultrasound localization in conformal radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Patel, Rakesh R.; Orton, Nigel; Tome, Wolfgang A.; Chappell, Rick; Ritter, Mark A.

    2003-01-01

    Background and purpose: To compare the rectal wall and bladder volume in the high dose region with or without the use of a balloon catheter with both three-dimensional (3D)-conformal and intensity modulated radiation therapy (CRT, IMRT) approaches in the treatment of prostate cancer. Material and methods: Five patients with a wide range of prostate volumes and treated with primary external beam radiation therapy for localized prostate cancer were selected for analysis. Pinnacle TM treatment plans were generated utilizing a 3D conformal six-field design and an IMRT seven coplanar-field plan with a novel, three-step optimization and with ultrasound localization. Separate plans were devised with a rectal balloon deflated or air inflated with and without inclusion of the seminal vesicles (SV) in the target volume. The prescription dose was 76 Gy in 38 fractions of 2 Gy each. Cumulative dose-volume histograms (DVHs) were analyzed for the planning target volume (PTV), rectal wall, and bladder with an inflated (60 cc air) or deflated balloon with and without SV included. The volumes of rectal wall and bladder above 60, 65, and 70 Gy with each treatment approach were evaluated. Results: Daily balloon placement was well-tolerated with good patient positional reproducibility. Inflation of the rectal balloon in all cases resulted in a significant decrease in the absolute volume of rectal wall receiving greater than 60, 65, or 70 Gy. The rectal sparing ratio (RSR), consisting of a structure's high dose volume with the catheter inflated, divided by the volume with the catheter deflated, was calculated for each patient with and without seminal vesicle inclusion for 3D-CRT and IMRT. For 3D-CRT, RSRs with SV included were 0.59, 0.59, and 0.56 and with SV excluded were 0.60, 0.58, and 0.54 at doses of greater than 60, 65, and 70 Gy, respectively. Similarly, for IMRT, the mean RSRs were 0.59, 0.59, and 0.63 including SV and 0.71, 0.66, and 0.67 excluding SV at these same dose levels

  17. Progress of radiotherapy by three-dimensional treatment planning

    International Nuclear Information System (INIS)

    Imada, Hajime; Nomoto, Satoshi; Takahashi, Hiroyuki; Nakata, Hajime

    1998-01-01

    The recent progress of three-dimensional radiation treatment planning was reviewed. And clinical cases such as lung cancer and breast cancer are introduced. In the University of Occupational and Development Health, the treatment system FOCUS which is made up of CT simulator and linac was used mainly. Three-dimensional treatment planning was carried for about 90% of 330 patients who underwent radiotherapy for one year. The target becomes to be accurate and dose distribution with all CT slices in radiation field can be confirmed by using three-dimensional radiation treatment planning apparatus. High dose irradiation localized to tumor part is possible. Relations between total dose and volume of normal tissue and/or tumor can be estimated numerically and easily by DVH. A prediction of indication and affection became possible by this procedure. In conclusion, generalization of three-dimensional radiation treatment planning will bring progress of more effective radiotherapy with less adverse reaction. (K.H.). 21 refs

  18. Cancer Trials Ireland (ICORG) 06-34: A multi-centre clinical trial using three-dimensional conformal radiation therapy to reduce the toxicity of palliative radiation for lung cancer.

    Science.gov (United States)

    McDermott, Ronan L; Armstrong, John G; Thirion, Pierre; Dunne, Mary; Finn, Marie; Small, Cormac; Byrne, Mary; O'Shea, Carmel; O'Sullivan, Lydia; Shannon, Aoife; Kelly, Emma; Hacking, Dayle J

    2018-05-01

    Cancer Trials Ireland (ICORG) 06-34: A multi-centre clinical trial using three-dimensional conformal radiation therapy to reduce the toxicity of palliative radiation for lung cancer. NCT01176487. Trials of radiation therapy for the palliation of intra-thoracic symptoms from locally advanced non-small cell lung cancer (NSCLC) have concentrated on optimising fractionation and dose schedules. In these trials, the rates of oesophagitis induced by this "palliative" therapy have been unacceptably high. In contrast, this non-randomised, single-arm trial was designed to assess if more technically advanced treatment techniques would result in equivalent symptom relief and reduce the side-effect of symptomatic oesophagitis. Thirty-five evaluable patients with symptomatic locally advanced or metastatic NSCLC were treated using a three-dimensional conformal technique (3-DCRT) and standardised dose regimens of 39 Gy in 13 fractions, 20 Gy in 5 fractions or 17 Gy in 2 fractions. Treatment plans sought to minimise oesophageal dose. Oesophagitis was recorded during treatment, at two weeks, one month and three months following radiation therapy and 3-6 monthly thereafter. Mean dose to the irradiated oesophagus was calculated for all treatment plans. Five patients (14%) had experienced grade 2 oesophagitis or dysphagia or both during treatment and 2 other patients had these side effects at the 2-week follow-up. At follow-up of one month after therapy, there was no grade two or higher oesophagitis or dysphagia reported. 22 patients were eligible for assessment of late toxicity. Five of these patients reported oesophagitis or dysphagia (one had grade 3 dysphagia, two had grade 2 oesophagitis, one of whom also had grade 2 dysphagia). Quality of Life (QoL) data at baseline and at 1-month follow up were available for 20 patients. At 1-month post radiation therapy, these patients had slightly less trouble taking a short walk, less shortness of breath, did not feel as weak, had

  19. Optimisation of radiotherapy for carcinoma of the parotid gland: a comparison of conventional, three-dimensional conformal, and intensity-modulated techniques

    International Nuclear Information System (INIS)

    Nutting, Christopher M.; Rowbottom, Carl G.; Cosgrove, Vivian P.; Henk, J. Michael; Dearnaley, David P.; Robinson, Martin H.; Conway, John; Webb, Steve

    2001-01-01

    Background and purpose: To compare external beam radiotherapy techniques for parotid gland tumours using conventional radiotherapy (RT), three-dimensional conformal radiotherapy (3DCRT), and intensity-modulated radiotherapy (IMRT). To optimise the IMRT techniques, and to produce an IMRT class solution. Materials and methods: The planning target volume (PTV), contra-lateral parotid gland, oral cavity, brain-stem, brain and cochlea were outlined on CT planning scans of six patients with parotid gland tumours. Optimised conventional RT and 3DCRT plans were created and compared with inverse-planned IMRT dose distributions using dose-volume histograms. The aim was to reduce the radiation dose to organs at risk and improve the PTV dose distribution. A beam-direction optimisation algorithm was used to improve the dose distribution of the IMRT plans, and a class solution for parotid gland IMRT was investigated. Results: 3DCRT plans produced an equivalent PTV irradiation and reduced the dose to the cochlea, oral cavity, brain, and other normal tissues compared with conventional RT. IMRT further reduced the radiation dose to the cochlea and oral cavity compared with 3DCRT. For nine- and seven-field IMRT techniques, there was an increase in low-dose radiation to non-target tissue and the contra-lateral parotid gland. IMRT plans produced using three to five optimised intensity-modulated beam directions maintained the advantages of the more complex IMRT plans, and reduced the contra-lateral parotid gland dose to acceptable levels. Three- and four-field non-coplanar beam arrangements increased the volume of brain irradiated, and increased PTV dose inhomogeneity. A four-field class solution consisting of paired ipsilateral coplanar anterior and posterior oblique beams (15, 45, 145 and 170 degree sign from the anterior plane) was developed which maintained the benefits without the complexity of individual patient optimisation. Conclusions: For patients with parotid gland tumours

  20. SU-E-T-63: Carotid Sparing Tomohelical Three Dimensional Conformal Radiotherapy for T1N0 Glottic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hong, C; Ju, S; Ahn, Y; Oh, D; Noh, J; Chung, K; Kim, J; Han, Y; Choi, D [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2014-06-01

    Purpose: We investigated the dosimetric benefit and treatment efficiency of carotid-sparing TomoHelical (TH) three-dimensional conformal radiotherapy (3DCRT) for early glottic cancer. Methods: Computed tomography (CT) simulation was performed for 10 patients with early-stage (T1N0M0) glottic squamous cell carcinoma. The clinical target volume, planning target volume (PTV), carotid artery (CA), and spinal cord (SP) were delineated for each CT data set. Two-field 3DCRT (2F-3DCRT), three-field intensity-modulated radiation therapy (IMRT) (3F-IMRT), TomoHelical-IMRT (TH-IMRT), and TH-3DCRT plans were generated, with a total prescribed dose of 67.5 Gy in 30 fractions to the PTV for each patient. In order to evaluate plan quality, dosimetric characteristics were compared in terms of the conformity index (CI) and homogeneity index (HI) for the PTV, V35, V50, and V63 for the CAs and in terms of the maximum dose for the SP. Additionally, treatment planning and delivery times were compared to evaluate treatment efficiency. Results: The CIs for 3F-IMRT (0.650±0.05), TH-IMRT (0.643±0.03), and TH-3DCRT (0.631±0.03) were much better than that for 2F-3DCRT (0.318±0.03). The HIs for TH-IMRT (1.053±0.01) and TH-3DCRT (1.055±0.01) were slightly better than those for 2F-3DCRT (1.062±0.01) and 3F-IMRT (1.091±0.007). 2F-3DCRT showed poor CA sparing in terms of the V35, V50, and V63 compared to 3F-IMRT, TH-IMRT, and TH-3DCRT (p<0.05), whereas there was no significant dose difference between 3F-IMRT, TH-IMRT, and TH-3DCRT (p>0.05). The maximum dose to the SP with all plans was below 45 Gy. The treatment planning times for 2F-3DCRT (5.9±0.66 min) and TH-3DCRT (7.32±0.94 min) were much lower than those for 3F-IMRT (45.51±2.76 min) and TH-IMRT (35.58±4.41 min), whereas the delivery times with all plans was below 3 minutes. Conclusion: TH-3DCRT showed excellent carotid sparing capability, comparable to that with TH-IMRT, with high treatment efficiency and short planning and

  1. Radiation therapy treatment planning: CT, MR imaging and three-dimensional planning

    International Nuclear Information System (INIS)

    Lichter, A.S.

    1987-01-01

    The accuracy and sophistication of radiation therapy treatment planning have increased rapidly in the last decade. Currently, CT-based treatment planning is standard throughout the country. Care must be taken when CT is used for treatment planning because of clear differences between diagnostic scans and scans intended for therapeutic management. The use of CT in radiation therapy planning is discussed and illustrated. MR imaging adds another dimension to treatment planning. The ability to use MR imaging directly in treatment planning involves an additional complex set of capabilities from a treatment planning system. The ability to unwarp the geometrically distorted MR image is a first step. Three-dimensional dose calculations are important to display the dose on sagittal and acoronal sections. The ability to integrate the MR and CT images into a unified radiographic image is critical. CT and MR images are two-dimensional representations of a three-dimensional problem. Through sophisticated computer graphics techniques, radiation therapists are now able to integrate a three-dimensional image of the patient into the treatment planning process. This allows the use of noncoplanar treatment plans and a detailed analysis of tumor and normal tissue anatomy; it is the first step toward a fully conformational treatment planning system. These concepts are illustrated and future research goals outlined

  2. Three-dimensional neutron dose distribution in the environment around a 1-GeV electron synchrotron facility at INS

    International Nuclear Information System (INIS)

    Uwamino, Y.; Nakamura, T.

    1987-01-01

    The three-dimensional (surface and altitude) skyshine neutron-dose-equivalent distribution around the 1-GeV electron synchrotron (ES) of the Institute for Nuclear Study, University of Tokyo, was measured with a high-sensitivity dose-equivalent counter. The neutron spectrum in the environment was also measured with a multimoderator spectrometer incorporating a 3 He counter. The dose-equivalent distribution and the leakage neutron spectrum at the surface of the ES building were measured with a Studsvik 2202D counter and the multimoderator spectrometer, including an indium activation detector. Skyshine neutron transport calculations, beginning with the photoneutron spectrum and yielding the dose-equivalent distribution in the environment, were performed with the DOT3.5 code and two Monte Carlo codes, MMCR-2 and MMCR-3, using the DLC-87/HILO group cross sections. The calculated neutron spectra at the top surface of the concrete ceiling and at a point 111 m from the ES agreed well with the measured results, and the calculated three-dimensional dose-equivalent distribution also agreed. The dose value increased linearly with altitude, and the slope was estimated for neutron-producing facilities. (author)

  3. Intensity modulated radiotherapy in early stage Hodgkin lymphoma patients: Is it better than three dimensional conformal radiotherapy?

    International Nuclear Information System (INIS)

    De Sanctis, Vitaliana; Chiacchiararelli, Laura; Enrici, Riccardo Maurizi; Bolzan, Chiara; D’Arienzo, Marco; Bracci, Stefano; Fanelli, Alessandro; Cox, Maria Christina; Valeriani, Maurizio; Osti, Mattia F; Minniti, Giuseppe

    2012-01-01

    Cure rate of early Hodgkin Lymphoma are high and avoidance of late toxicities is of paramount importance. This comparative study aims to assess the normal tissue sparing capability of intensity-modulated radiation therapy (IMRT) versus standard three-dimensional conformal radiotherapy (3D-CRT) in terms of dose-volume parameters and normal tissue complication probability (NTCP) for different organs at risk in supradiaphragmatic Hodgkin Lymphoma (HL) patients. Ten HL patients were actually treated with 3D-CRT and all treatments were then re-planned with IMRT. Dose-volume parameters for thyroid, oesophagus, heart, coronary arteries, lung, spinal cord and breast were evaluated. Dose-volume histograms generated by TPS were analyzed to predict the NTCP for the considered organs at risk, according to different endpoints. Regarding dose-volume parameters no statistically significant differences were recorded for heart and origin of coronary arteries. We recorded statistically significant lower V30 with IMRT for oesophagus (6.42 vs 0.33, p = 0.02) and lungs (4.7 vs 0.1 p = 0.014 for the left lung and 2.59 vs 0.1 p = 0.017 for the right lung) and lower V20 for spinal cord (17.8 vs 7.2 p = 0.02). Moreover the maximum dose to the spinal cord was lower with IMRT (30.2 vs 19.9, p <0.001). Higher V10 with IMRT for thyroid (64.8 vs 95, p = 0.0019) and V5 for lungs (30.3 vs 44.8, p = 0.03, for right lung and 28.9 vs 48.1, p = 0.001 for left lung) were found, respectively. Higher V5 and V10 for breasts were found with IMRT (V5: 4.14 vs 20.6, p = 0.018 for left breast and 3.3 vs 17, p = 0.059 for right breast; V10: 2.5 vs 13.6 p = 0.035 for left breast and 1.7 vs 11, p = 0.07 for the right breast.) As for the NTCP, our data point out that IMRT is not always likely to significantly increase the NTCP to OARs. In HL male patients IMRT seems feasible and accurate while for women HL patients IMRT should be used with caution

  4. Three-dimensional treatment planning for postoperative radiotherapy in patients with node-positive cervical cancer. Comparison between a conventional and a conformal technique

    Energy Technology Data Exchange (ETDEWEB)

    Olofsen-van Acht, M.J.J.; Quint, S.; Seven, M.; Berg, H.A. van den; Levendag, P.C. [University Hospital Rotterdam (Netherlands). Dept. of Radiation Oncology; Santvoort, J.P.C. van [University Hospital Rotterdam (Netherlands). Subdivision of Clinical Physics; Logmans, A. [University Hospital Rotterdam (Netherlands). Dept. of Gynecologic Oncology

    1999-09-01

    Purpose: Reduction of irradiated small bowel volume, using a conformal three-dimensional treatment planning technique in postoperative radiotherapy of cervical cancer patients. Patients and Methods: Large gynecological treatment fields including the para-aortic nodes were analyzed in 15 patients. A conventional treatment plan with anterior and posterior (AP-PA) parallel opposed fields and a 3D 4-field conformal radiotherapy plan with a central blocking of small bowel were compared for each patient. Dose-volume histograms and dose parameters were established. Because of the tolerance constraints of the small bowel, the cumulative dose applied to the target was 48.6 Gy. Results: The mean Tumor Control Probability (TCP) values for both the conventional and the conformal technique were 0.60 and 0.61, respectively, with ranges of 0.56 to 0.67 and 0.57 to 0.66, respectively. The mean volume receiving 95% or more of the prescribed dose (V95) of the small bowel was 47.6% (32.5 to 66.3%) in the AP-PA technique and 14.9% (7.0 to 22.5%) in the conformal technique (p<0.001), indicating a significant reduction in irradiated volume of small bowel in the higher dose range. The mean Normal Tissue Complication Probability (NTCP) decreased from 0.11 to 0.03 with the conformal plan. In patients who received a pedicled omentoplasty during surgery, the mean V95 for small bowel could be reduced to 8.5% (7.0 to 9.9%). The mean median dose to the kidneys was only slightly elevated in the conformal treatment. Especially the mean dose to the right kidney in conventional vs conformal treatment was 3.3 vs 7.9 Gy. The mean near-minimum dose (D95) to the rectosigmoid decreased from 48.4 to 30.1 Gy in the conformal plan compared to the conventional plan. Conclusion: The small bowel dose can be significantly reduced with 3D treatment planning, particularly if a predicled omentoplasty is performed. This allows dose escalation to the tumor region without unacceptable toxicity for the small bowel

  5. Incidence of late rectal bleeding in high-dose conformal radiotherapy of prostate cancer using equivalent uniform dose-based and dose-volume-based normal tissue complication probability models

    International Nuclear Information System (INIS)

    Soehn, Matthias; Yan Di; Liang Jian; Meldolesi, Elisa; Vargas, Carlos; Alber, Markus

    2007-01-01

    Purpose: Accurate modeling of rectal complications based on dose-volume histogram (DVH) data are necessary to allow safe dose escalation in radiotherapy of prostate cancer. We applied different equivalent uniform dose (EUD)-based and dose-volume-based normal tissue complication probability (NTCP) models to rectal wall DVHs and follow-up data for 319 prostate cancer patients to identify the dosimetric factors most predictive for Grade ≥ 2 rectal bleeding. Methods and Materials: Data for 319 patients treated at the William Beaumont Hospital with three-dimensional conformal radiotherapy (3D-CRT) under an adaptive radiotherapy protocol were used for this study. The following models were considered: (1) Lyman model and (2) logit-formula with DVH reduced to generalized EUD (3) serial reconstruction unit (RU) model (4) Poisson-EUD model, and (5) mean dose- and (6) cutoff dose-logistic regression model. The parameters and their confidence intervals were determined using maximum likelihood estimation. Results: Of the patients, 51 (16.0%) showed Grade 2 or higher bleeding. As assessed qualitatively and quantitatively, the Lyman- and Logit-EUD, serial RU, and Poisson-EUD model fitted the data very well. Rectal wall mean dose did not correlate to Grade 2 or higher bleeding. For the cutoff dose model, the volume receiving > 73.7 Gy showed most significant correlation to bleeding. However, this model fitted the data more poorly than the EUD-based models. Conclusions: Our study clearly confirms a volume effect for late rectal bleeding. This can be described very well by the EUD-like models, of which the serial RU- and Poisson-EUD model can describe the data with only two parameters. Dose-volume-based cutoff-dose models performed worse

  6. Implementation of three-dimensional planning in brachytherapy of high dose rate for gynecology therapies

    International Nuclear Information System (INIS)

    Sales, Camila Pessoa de

    2015-01-01

    This work aims to implement the three-dimensional (3D) planning for gynecological brachytherapy treatments. For this purpose, tests of acceptance and commissioning of brachytherapy equipment were performed to establish a quality and periodic assurance program. For this purpose, an important step was searching for a material to be used as a dummy source, since the applicators do not have any specific dummy. In addition, the validation of the use of applicators library was made for reconstruction in computed tomography (CT) and magnetic resonance imaging (MRI). In order to validate 3D planning, comparison of doses in dose assessment points used in bidimensional (2D) plans have been performed with volumetric doses to adjacent organs to the tumor. Finally, a protocol was established for 3D brachytherapy planning alternately using magnetic resonance image (MRI) and CT images, making evaluation of the dose in the tumor through the recording of MR and CT images. It was not possible to find a suitable material that could be used as dummy in MRI. However, the acquisition of the license's library for the applicators made possible the 3D planning based on MRI. No correlation was found between volumetric and specific doses analyzed, showing the importance of the implementation of 3D planning. The average ratio between D 2cc and ICRU Bladder dose was 1,74, 22% higher than the ratio found by others authors. For the rectum, D 2cc was less than dose point for 60% of fractions; the average difference was 12,5%. The average ratio between D 2cc and point dose rectum, 0,85, is equivalent to the value showed by Kim et al, 0,91. The D 2cc for sigmoid was 69% higher than point dose used, unless it was not possible compare this value, since the sigmoid point used in the 2D procedures is not used in others institutes. Relative dose in 2 cc of sigmoid was 57% of the prescription dose, the same value was found by in literature. This work enabled the implementation of a viable

  7. Predicting Three-Dimensional Conformations of Peptides Constructed of Only Glycine, Alanine, Aspartic Acid, and Valine

    Science.gov (United States)

    Oda, Akifumi; Fukuyoshi, Shuichi

    2015-06-01

    The GADV hypothesis is a form of the protein world hypothesis, which suggests that life originated from proteins (Lacey et al. 1999; Ikehara 2002; Andras 2006). In the GADV hypothesis, life is thought to have originated from primitive proteins constructed of only glycine, alanine, aspartic acid, and valine ([GADV]-proteins). In this study, the three-dimensional (3D) conformations of randomly generated short [GADV]-peptides were computationally investigated using replica-exchange molecular dynamics (REMD) simulations (Sugita and Okamoto 1999). Because the peptides used in this study consisted of only 20 residues each, they could not form certain 3D structures. However, the conformational tendencies of the peptides were elucidated by analyzing the conformational ensembles generated by REMD simulations. The results indicate that secondary structures can be formed in several randomly generated [GADV]-peptides. A long helical structure was found in one of the hydrophobic peptides, supporting the conjecture of the GADV hypothesis that many peptides aggregated to form peptide multimers with enzymatic activity in the primordial soup. In addition, these results indicate that REMD simulations can be used for the structural investigation of short peptides.

  8. Promising survival with three-dimensional conformal radiation therapy for non-small cell lung cancer

    International Nuclear Information System (INIS)

    Armstrong, John; Raben, Adam; Zelefsky, Michael; Burt, Michael; Leibel, Steve; Burman, Chandra; Kutcher, Gerard; Harrison, Louis; Hahn, Cathy; Ginsberg, Robert; Rusch, Valerie; Kris, Mark; Fuks, Zvi

    1997-01-01

    Purpose: Local failure is a major obstacle to the cure of locally advanced non small-cell lung cancer. Three-dimensional conformal radiation therapy (3-DCRT) selects optimal treatment parameters to increase dose to tumor and reduce normal tissue dose, potentially representing an enhancement of the therapeutic ratio of radiation therapy for lung cancer. We performed this analysis of 45 non-small cell lung cancer patients treated with 3-DCRT alone, to evaluate the ability of computer derived lung dose volume histograms to predict serious pulmonary toxicity, to assess the feasibility of this approach, and to examine the resulting survival. Methods: There were 28 males (62%) and 17 females (38%). The median age was 65 (range: 38-82). Tumor stage was Stage I/II in 13%, IIIa in 42%, and IIIb in 44%. The histology was squamous in 44%, adenocarcinoma in 36%, and other non-small cell histologies in the others. Only 47% of patients. had combined favorable prognostic factors (i.e. KPS ≤ 80, and ≤5% wt. loss). The median dose of radiation to gross disease was 70.2 Gy (range: 52.2-72 Gy) delivered in fractions of 1.8 Gy, 5 days per week. Results: Seven patients did not complete 3-DCRT due to disease progression outside the port. Follow-up data are mature: the median follow up of the 6 survivors is 43.5 months (35-59). Thoracic progression occurred in 46%. Median survival (all 45 patients.) is 15.7 months and survival is 32% at 2 years and 12% at 59 months. Pulmonary toxicity ≥grade 3 occurred in 9% of patients. Dose volume histograms were available in 31 patients and showed a correlation between risk of pulmonary toxicity and indices of dose to lung parenchyma. Grade 3 or higher pulmonary toxicity occurred in 38% ((3(8))) of patients with >30% of lung volume receiving ≥25 Gy, versus 4% ((1(23))) of patients with ≤30% lung receiving ≥25 Gy (P = 0.04). Grade 3 or higher pulmonary toxicity occurred in 29% ((4(14))) of patients with a predicted pulmonary normal tissue

  9. Beam intensity scanner system for three dimensional dose verification of IMRT

    International Nuclear Information System (INIS)

    Vahc, Young W.; Kwon, Ohyun; Park, Kwangyl; Park, Kyung R.; Yi, Byung Y.; Kim, Keun M.

    2003-01-01

    Patient dose verification is clinically one of the most important parts in the treatment delivery of radiation therapy. The three dimensional (3D) reconstruction of dose distribution delivered to target volume helps to verify patient dose and determine the physical characteristics of beams used in IMRT. Here we present beam intensity scanner (BInS) system for the pre-treatment dosimetric verification of two dimensional photon intensity. The BInS is a radiation detector with a custom-made software for dose conversion of fluorescence signals from scintillator. The scintillator is used to produce fluorescence from the irradiation of 6 MV photons on a Varian Clinac 21EX. The digitized fluoroscopic signals obtained by digital video camera-based scintillator (DVCS) will be processed by our custom made software to reproduce 3D- relative dose distribution. For the intensity modulated beam (IMB), the BInS calculates absorbed dose in absolute beam fluence which is used for the patient dose distribution. Using BInS, we performed various measurements related to IMRT and found the following: (1) The 3D-dose profiles of the IMBs measured by the BInS demonstrate good agreement with radiographic film, pin type ionization chamber and Monte Carlo simulation. (2) The delivered beam intensity is altered by the mechanical and dosimetric properties of the collimation of dynamic and/or step MLC system. This is mostly due to leaf transmission, leaf penumbra scattered photons from the round edges of leaves, and geometry of leaf. (3) The delivered dose depends on the operational detail of how to make multi leaf opening. These phenomena result in a fluence distribution that can be substantially different from the initial and calculated intensity modulation and therefore, should be taken into account by the treatment planning for accurate dose calculations delivered to the target volume in IMRT. (author)

  10. When treating prostate cancer with three-dimensional conformal radiation therapy the impact of bladder filling status on the volume and integral dose distribution of the target and critical organs should be kept in mind

    International Nuclear Information System (INIS)

    Liu Yueping; Liu Xinfan; Li Yexiong; Guang Ying

    2007-01-01

    Objective: In prostate cancer treated with three-dimensional conformal radiation therapy (3DCRT), we tried to prospectively assess the impact of the filling status of bladder on the volume and the integral dose distribution to the target and surrounding critical organs. Methods: Ten patients with stage T1-T2N0M0 prostate cancer were studied. All patients received 3DCRT to the prostate and inferior seminal vesicle. One hour before CT simulation, the bladder was first voided, and then 400 ml of oral contrast solution was given at every half hour before the CT scan. Urethral catheterization was used for voiding or distending the bladder. When distending the bladder, 250-300 ml of contrast was injected into the bladder with the patient fixed at the supine position. Two sets of transverse images were taken for the whole pelvis in empty and full bladder. After the target and critical organs (bladder, rectum, pelvic small bowel, and femoral heads) were contoured, a treatment plan of three-dimensional conformal radiotherapy was made using the CMS Focus-Xio treatment planning system. The volume and mean doses of CTV, PTV, rectum, bladder, femoral heads, and small bowel with the bladder empty and full were evaluated. The percentage of volume which received 50 Gy in the rectum and bladder, 30 Gy in the femoral heads, and the maximal dose to the pelvic small bowel were also assessed . The variability of volume and dose distribution in these targets or organs was compared between the empty and full bladder status. Results: Comparing to the bladder empty status, full bladder led to a mean increase of 499% in the bladder volume, (67±9) ml and (336±48) ml (P=0.000), respectively. No volume change was found in the CTV, PTV, rectum, femoral heads and pel- vic small bowel(P=0.153,0.501,0.929,0.771,0.081). The mean dose to the bladder in full status was only 35% of that in empty status, (1501±201 ) cGy and (4267±216) cGy(P =0.000), respectively. The mean dose to the pelvic small

  11. Evaluation of the treatment planning system of three-dimensional conformal external radiotherapy in Hospital Mexico of San Jose, Costa Rica

    International Nuclear Information System (INIS)

    Venegas Rojas, Deybith

    2014-01-01

    An evaluation and analysis are realized of dosimetry of the treatment planning system (TPS) of three-dimensional conformal external radiotherapy in the Servicio de Radioterapia of the Hospital Mexico of Costa Rica. An evaluation procedure is proposed based on IAEA-TECDOC-1540 document, and may continue to be applied periodically in this or other radiotherapy services. Tests realized have checked the representation of distances and electronics densities transferred to the TPS, match with those of real objects. The 16 tests applied have represented situations of real treatments with different configurations and beam modifiers in the equipment used daily. The tests have measured the absorbed dose to water in different significant points at different depths, using photon beams of 6 MeV and 18 MeV. The physical parameters of the tests were simulated. The absorbed dose has been calculated at specified points. The XiO and Eclipse TPS have been used with the calculation algorithms: Superposition, Convolution and AAA. The results of the calculations are evaluated with statistical methods and comparing them with the measurements of absorbed dose. A generalized tendency has been detected toward negative relative errors, implying an underestimation of the dose by the TPS; due to a difference found in the accelerator output factor respect to its commissioning. The AAA algorithm has determined a better performance, although with greater difficulties of calculus in the region of build-up. Convolution and Superposition algorithms have had similar performances and both have presented problems in high depths and out of edges of the fields. The result of the dosimetric evaluation has been satisfactory in real conditions of equipment; but several particularities have been found that should be reviewed and adjusted. The precision of the TPS has been adequate in the majority of situations important for treatment planning. [author] [es

  12. Study on the photoneutrons produced in 15 MV medical linear accelerators : Comparison of three dimensional conformal radiotherapy and intensity modulated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Oh Nam [Gangneung Asan Hospital, Gangneung (Korea, Republic of); Yang, Oh Nam; Lim, Cheong Hwan [Hanseo Univ., Seosan (Korea, Republic of)

    2012-12-15

    Intensity-modulated radiotherapy(IMRT) have the ability to provide better dose conformity and sparing of critical normal tissues than three-dimensional radiotherapy(3DCRT). Especially, with the benefit of health insurance in 2011, its use now increasingly in many modern radiotherapy departments. Also the use of linear accelerator with high-energy photon beams over 10 MV is increasing. As is well known, these linacs have the capacity to produce photoneutrons due to photonuclear reactions in materials with a large atomic number such as the target, flattening filters, collimators, and multi-leaf collimators(MLC). MLC-based IMRT treatments increase the monitor units and the probability of production of photoneutrons from photon-induced nuclear reactions. The purpose of this study is to quantitatively evaluate the dose of photoneutrons produced from 3DCRT and IMRT technique for Rando phantom in cervical cancer. We performed the treatment plans with 3DCRT and IMRT technique using Rando phantom for treatment of cervical cancer. An Rando phantom placed on the couch in the supine position was irradiated using 15 MV photon beams. Optically stimulated luminescence dosimeters(OSLD) were attached to 4 different locations (abdomen, chest, head and neck, eyes) and from center of field size and measured 5 times each of locations. Measured neutron dose from IMRT technique increased by 9.0, 8.6, 8.8, and 14 times than 3DCRT technique for abdomen, chest, head and neck, and eyes, respectively. When using IMRT with 15 MV photon beams, the photoneutrons contributed a significant portion on out-of-field. It is difficult to prevent high energy photon beams to produce the photoneutrons due to physical properties, if necessary, It is difficult to prevent high energy photon beams to produce the photoneutrons due to physical properties, if necessary, it is need to provide the additional safe shielding on a linear accelerator and should therefore reduce the out-of-field dose.

  13. Study on the photoneutrons produced in 15 MV medical linear accelerators : Comparison of three dimensional conformal radiotherapy and intensity modulated radiotherapy

    International Nuclear Information System (INIS)

    Yang, Oh Nam; Yang, Oh Nam; Lim, Cheong Hwan

    2012-01-01

    Intensity-modulated radiotherapy(IMRT) have the ability to provide better dose conformity and sparing of critical normal tissues than three-dimensional radiotherapy(3DCRT). Especially, with the benefit of health insurance in 2011, its use now increasingly in many modern radiotherapy departments. Also the use of linear accelerator with high-energy photon beams over 10 MV is increasing. As is well known, these linacs have the capacity to produce photoneutrons due to photonuclear reactions in materials with a large atomic number such as the target, flattening filters, collimators, and multi-leaf collimators(MLC). MLC-based IMRT treatments increase the monitor units and the probability of production of photoneutrons from photon-induced nuclear reactions. The purpose of this study is to quantitatively evaluate the dose of photoneutrons produced from 3DCRT and IMRT technique for Rando phantom in cervical cancer. We performed the treatment plans with 3DCRT and IMRT technique using Rando phantom for treatment of cervical cancer. An Rando phantom placed on the couch in the supine position was irradiated using 15 MV photon beams. Optically stimulated luminescence dosimeters(OSLD) were attached to 4 different locations (abdomen, chest, head and neck, eyes) and from center of field size and measured 5 times each of locations. Measured neutron dose from IMRT technique increased by 9.0, 8.6, 8.8, and 14 times than 3DCRT technique for abdomen, chest, head and neck, and eyes, respectively. When using IMRT with 15 MV photon beams, the photoneutrons contributed a significant portion on out-of-field. It is difficult to prevent high energy photon beams to produce the photoneutrons due to physical properties, if necessary, It is difficult to prevent high energy photon beams to produce the photoneutrons due to physical properties, if necessary, it is need to provide the additional safe shielding on a linear accelerator and should therefore reduce the out-of-field dose

  14. Comparison study of the partial-breast irradiation techniques: Dosimetric analysis of three-dimensional conformal radiation therapy, electron beam therapy, and helical tomotherapy depending on various tumor locations

    International Nuclear Information System (INIS)

    Kim, Min-Joo; Park, So-Hyun; Son, Seok-Hyun; Cheon, Keum-Seong; Choi, Byung-Ock; Suh, Tae-Suk

    2013-01-01

    The partial-breast irradiation (PBI) technique, an alternative to whole-breast irradiation, is a beam delivery method that uses a limited range of treatment volume. The present study was designed to determine the optimal PBI treatment modalities for 8 different tumor locations. Treatment planning was performed on computed tomography (CT) data sets of 6 patients who had received lumpectomy treatments. Tumor locations were classified into 8 subsections according to breast quadrant and depth. Three-dimensional conformal radiation therapy (3D-CRT), electron beam therapy (ET), and helical tomotherapy (H-TOMO) were utilized to evaluate the dosimetric effect for each tumor location. Conformation number (CN), radical dose homogeneity index (rDHI), and dose delivered to healthy tissue were estimated. The Kruskal-Wallis, Mann-Whitney U, and Bonferroni tests were used for statistical analysis. The ET approach showed good sparing effects and acceptable target coverage for the lower inner quadrant—superficial (LIQ-S) and lower inner quadrant—deep (LIQ-D) locations. The H-TOMO method was the least effective technique as no evaluation index achieved superiority for all tumor locations except CN. The ET method is advisable for treating LIQ-S and LIQ-D tumors, as opposed to 3D-CRT or H-TOMO, because of acceptable target coverage and much lower dose applied to surrounding tissue

  15. Clinical Applications of 3-D Conformal Radiotherapy

    Science.gov (United States)

    Miralbell, Raymond

    Although a significant improvement in cancer cure (i.e. 20% increment) has been obtained in the last 2-3 decades, 30-40% of patients still fail locally after curative radiotherapy. In order to improve local tumor control rates with radiotherapy high doses to the tumor volume are frequently necessary. Three-dimensional conformal radiation therapy (3-D CRT) is used to denote a spectrum of radiation planning and delivery techniques that rely on three-dimensional imaging to define the target (tumor) and to distinguish it from normal tissues. Modern, high-precision radiotherapy (RT) techniques are needed in order to implement the goal of optimal tumor destruction delivering minimal dose to the non-target normal tissues. A better target definition is nowadays possible with contemporary imaging (computerized tomography, magnetic resonance imaging, and positron emission tomography) and image registration technology. A highly precise dose distributions can be obtained with optimal 3-D CRT treatment delivery techniques such as stereotactic RT, intensity modulated RT (IMRT), or protontherapy (the latter allowing for in-depth conformation). Patient daily set-up repositioning and internal organ immobilization systems are necessary before considering to undertake any of the above mentioned high-precision treatment approaches. Prostate cancer, brain tumors, and base of skull malignancies are among the sites most benefitting of dose escalation approaches. Nevertheless, a significant dose reduction to the normal tissues in the vicinity of the irradiated tumor also achievable with optimal 3-D CRT may also be a major issue in the treatment of pediatric tumors in order to preserve growth, normal development, and to reduce the risk of developing radiation induced diseases such as cancer or endocrinologic disorders.

  16. Dose evaluation of three-dimensional small animal phantom with film dosimetry

    International Nuclear Information System (INIS)

    Han, Su Chul; Park, Seung Woo

    2017-01-01

    The weight of small animal dosimetry has been continuously increased in pre-clinical studies using radiation in small animals. In this study, three-dimensional(3D) small animal phantom was fabricated using 3D printer which has been continuously used and studied in the various fields. The absorbed dose of 3D animal phantom was evaluated by film dosimetry. Previously, the response of film was obtained from the materials used for production of 3D small animal phantom and compared with the bolus used as the tissue equivalent material in the radiotherapy. When irradiated with gamma rays from 0.5 Gy to 6 Gy, it was confirmed that there was a small difference of less than 1% except 0.5 Gy dose. And when small animal phantom was irradiated with 5 Gy, the difference between the irradiated dose and calculated dose from film was within 2%. Based on this study, it would be possible to increase the reliability of dose in pre-clinical studies using irradiation in small animals by evaluating dose of 3D small animal phantom

  17. Dose evaluation of three-dimensional small animal phantom with film dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Han, Su Chul [Div. of Medical Radiation Equipment, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of); Park, Seung Woo [Radilogcial and Medico-Oncological Sciences, University of Sciences and Technology, Daejeon (Korea, Republic of)

    2017-03-15

    The weight of small animal dosimetry has been continuously increased in pre-clinical studies using radiation in small animals. In this study, three-dimensional(3D) small animal phantom was fabricated using 3D printer which has been continuously used and studied in the various fields. The absorbed dose of 3D animal phantom was evaluated by film dosimetry. Previously, the response of film was obtained from the materials used for production of 3D small animal phantom and compared with the bolus used as the tissue equivalent material in the radiotherapy. When irradiated with gamma rays from 0.5 Gy to 6 Gy, it was confirmed that there was a small difference of less than 1% except 0.5 Gy dose. And when small animal phantom was irradiated with 5 Gy, the difference between the irradiated dose and calculated dose from film was within 2%. Based on this study, it would be possible to increase the reliability of dose in pre-clinical studies using irradiation in small animals by evaluating dose of 3D small animal phantom.

  18. A three-dimensional dose-distribution estimation system using computerized image reconstruction

    International Nuclear Information System (INIS)

    Nishijima, Akihiko; Kidoya, Eiji; Komuro, Hiroyuki; Tanaka, Masato; Asada, Naoki.

    1990-01-01

    In radiotherapy planning, three dimensional (3-D) estimation of dose distribution has been very troublesome and time-consuming. To solve this problem, a simple and fast 3-D dose distribution image using a computer and Charged Couple Device (CCD) camera was developed. A series of X-ray films inserted in the phantom using a linear accelerator unit was exposed. The degree of film density was degitized with a CCD camera and a minicomputer (VAX 11-750). After that these results were compared with the present depth dose obtained by a JARP type dosimeter, with a dose error being less than 2%. The 3-D dose distribution image could accurately depict the density changes created by aluminum and air put into the phantom. The contrast resolution of the CCD camera seemed to be superior to the convention densitometer in the low-to-intermediate contrast range. In conclusion, our method seem to be very fast and simple for obtaining 3-D dose distribution images and is very effective when compared with the conventional method. (author)

  19. Two dimensional infinite conformal symmetry

    International Nuclear Information System (INIS)

    Mohanta, N.N.; Tripathy, K.C.

    1993-01-01

    The invariant discontinuous (discrete) conformal transformation groups, namely the Kleinian and Fuchsian groups Gamma (with an arbitrary signature) of H (the Poincare upper half-plane l) and the unit disc Delta are explicitly constructed from the fundamental domain D. The Riemann surface with signatures of Gamma and conformally invariant automorphic forms (functions) with Peterson scalar product are discussed. The functor, where the category of complex Hilbert spaces spanned by the space of cusp forms constitutes the two dimensional conformal field theory. (Author) 7 refs

  20. Radiation-induced esophagitis in local advanced non-small cell lung cancer after three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Tian Dandan; Wang Yuxiang; Qiu Rong; Zhu Shuchai; Tian Xiuming; Qiao Xueying

    2014-01-01

    Objective: To explore radiation-induced esophagitis and its related factors in the patients with local advanced non-small cell lung cancer (NSCLC) which were treated with three-dimensional conformal radiation therapy (3D-CRT). Methods: From January 2001 to December 2008, 203 patients who suffered from stage Ⅲ NSCLC were achieved, including 163 males and 40 females, with a median age of 63 years old, while 79 cases were in stage Ⅲ_a and 124 in stage Ⅲ_b. The equivalent median dose of tumor was 62 Gy(range of 50-78 Gy). Among them, 74 cases were administered with radiotherapy alone, 45 with sequential radiotherapy and chemotherapy, 87 cases with concurrent radiochemotherapy. Radiation esophagitis was evaluated with RTOG standard. The dosimetric parameters was estimated from dose volume histogrma (DVH). The clinical and dosimetric parameters of radiation esophagitis were evaluated by spearman correlatived univariate and Logistic multivariable analysis.Results After radiotherapy, out of 203 patients, 87 had acute radiation esophagitis(RE), 47 in grade 1, 37 in grade 2, and 3 in grade 3 RE. According to spearman correlatived analysis, the correlatived factors included ages, chemotherapy, GTV, PTV, the mean doses of PTV and lung, the max and mean dose of esophagus, V_4_0, V_4_5, V_5_0, V_5_5, V_6_0, length of esophagus (total circumference) treated with 45 Gy (LETT_4_5), and LETT_5_0 (r = -0.162-0.235, P 0.05). There were 21 factors, such as gender, age, smoking, clinical stage, site of tumor, chemotherapy, GTV, PTV, mean dose of PTV and lung, max and mean dose of esophagus, V_4_0-V_6_0 of esophagus, LETT_4_5_-_6_0, incorporated into multivariable analysis, only chemotherapy and V_4_5 of esophagus were independent predicted factors(Wald = 4.626, 9.882, P < 0.05). Conclusions: In local advanced NSCLC after 3D-CRT, chemotherapy(especially concurrent radiochemotherapy) could increase radiation-induced esophagitis. The parameter of DVH could also be used to predict

  1. Infinite-dimensional Lie algebras in 4D conformal quantum field theory

    International Nuclear Information System (INIS)

    Bakalov, Bojko; Nikolov, Nikolay M; Rehren, Karl-Henning; Todorov, Ivan

    2008-01-01

    The concept of global conformal invariance (GCI) opens the way of applying algebraic techniques, developed in the context of two-dimensional chiral conformal field theory, to a higher (even) dimensional spacetime. In particular, a system of GCI scalar fields of conformal dimension two gives rise to a Lie algebra of harmonic bilocal fields, V M (x, y), where the M span a finite dimensional real matrix algebra M closed under transposition. The associative algebra M is irreducible iff its commutant M' coincides with one of the three real division rings. The Lie algebra of (the modes of) the bilocal fields is in each case an infinite-dimensional Lie algebra: a central extension of sp(∞,R) corresponding to the field R of reals, of u(∞, ∞) associated with the field C of complex numbers, and of so*(4∞) related to the algebra H of quaternions. They give rise to quantum field theory models with superselection sectors governed by the (global) gauge groups O(N), U(N) and U(N,H)=Sp(2N), respectively

  2. Cylindrical Three-Dimensional Porous Anodic Alumina Networks

    Directory of Open Access Journals (Sweden)

    Pedro M. Resende

    2016-11-01

    Full Text Available The synthesis of a conformal three-dimensional nanostructure based on porous anodic alumina with transversal nanopores on wires is herein presented. The resulting three-dimensional network exhibits the same nanostructure as that obtained on planar geometries, but with a macroscopic cylindrical geometry. The morphological analysis of the nanostructure revealed the effects of the initial defects on the aluminum surface and the mechanical strains on the integrity of the three-dimensional network. The results evidence the feasibility of obtaining 3D porous anodic alumina on non-planar aluminum substrates.

  3. Conformal invariance and two-dimensional physics

    International Nuclear Information System (INIS)

    Zuber, J.B.

    1993-01-01

    Actually, physicists and mathematicians are very interested in conformal invariance: geometric transformations which keep angles. This symmetry is very important for two-dimensional systems as phase transitions, string theory or node mathematics. In this article, the author presents the conformal invariance and explains its usefulness

  4. Dosimetric Comparison of Three-Dimensional Conformal Proton Radiotherapy, Intensity-Modulated Proton Therapy, and Intensity-Modulated Radiotherapy for Treatment of Pediatric Craniopharyngiomas

    Energy Technology Data Exchange (ETDEWEB)

    Boehling, Nicholas S. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Grosshans, David R., E-mail: dgrossha@mdanderson.org [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Bluett, Jaques B. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Palmer, Matthew T. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Song, Xiaofei; Amos, Richard A.; Sahoo, Narayan [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Meyer, Jeffrey J.; Mahajan, Anita; Woo, Shiao Y. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

    2012-02-01

    Purpose: Cranial irradiation in pediatric patients is associated with serious long-term adverse effects. We sought to determine whether both three-dimensional conformal proton radiotherapy (3D-PRT) and intensity-modulated proton therapy (IMPT) compared with intensity-modulated radiotherapy (IMRT) decrease integral dose to brain areas known to harbor neuronal stem cells, major blood vessels, and other normal brain structures for pediatric patients with craniopharyngiomas. Methods and Materials: IMRT, forward planned, passive scattering proton, and IMPT plans were generated and optimized for 10 pediatric patients. The dose was 50.4 Gy (or cobalt Gy equivalent) delivered in 28 fractions with the requirement for planning target volume (PTV) coverage of 95% or better. Integral dose data were calculated from differential dose-volume histograms. Results: The PTV target coverage was adequate for all modalities. IMRT and IMPT yielded the most conformal plans in comparison to 3D-PRT. Compared with IMRT, 3D-PRT and IMPT plans had a relative reduction of integral dose to the hippocampus (3D-PRT, 20.4; IMPT, 51.3%{sup Asterisk-Operator }), dentate gyrus (27.3, 75.0%{sup Asterisk-Operator }), and subventricular zone (4.5, 57.8%{sup Asterisk-Operator }). Vascular organs at risk also had reduced integral dose with the use of proton therapy (anterior cerebral arteries, 33.3{sup Asterisk-Operator }, 100.0%{sup Asterisk-Operator }; middle cerebral arteries, 25.9%{sup Asterisk-Operator }, 100%{sup Asterisk-Operator }; anterior communicating arteries, 30.8{sup Asterisk-Operator }, 41.7%{sup Asterisk-Operator }; and carotid arteries, 51.5{sup Asterisk-Operator }, 77.6{sup Asterisk-Operator }). Relative reduction of integral dose to the infratentorial brain (190.7{sup Asterisk-Operator }, 109.7%{sup Asterisk-Operator }), supratentorial brain without PTV (9.6, 26.8%{sup Asterisk-Operator }), brainstem (45.6, 22.4%{sup Asterisk-Operator }), and whole brain without PTV (19.4{sup Asterisk

  5. Incidental irradiation of internal mammary lymph nodes in breast cancer: conventional two-dimensional radiotherapy versus conformal three-dimensional radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Leite, Elton Trigo Teixeira; Ugino, Rafael Tsuneki; Lopes, Mauricio Russo; Pelosi, Edilson Lopes; Silva, Joao Luis Fernandes da, E-mail: eltontt@gmail.com [Hospital Sirio-Libanes, Sao paulo, SP (Brazil). Departamento de Radiologia e Oncologia; Santana, Marco Antonio; Ferreira, Denis Vasconcelos; Carvalho, Heloisa de Andrade [Universidade de Sao Paulo (FM/USP), Sao Paulo, SP (Brazil). Faculdade de Medicina. Departamento de Radiologia e Oncologia

    2016-05-15

    Objective: to evaluate incidental irradiation of the internal mammary lymph nodes (IMLNs) through opposed tangential fields with conventional two-dimensional (2D) or three-dimensional (3D) radiotherapy techniques and to compare the results between the two techniques. Materials and Methods: This was a retrospective study of 80 breast cancer patients in whom radiotherapy of the IMLNs was not indicated: 40 underwent 2D radiotherapy with computed tomography for dosimetric control, and 40 underwent 3D radiotherapy. The total prescribed dose was 50.0 Gy or 50.4 Gy (2.0 or 1.8 Gy/day, respectively). We reviewed all plans and defined the IMLNs following the Radiation Therapy Oncology Group recommendations. For the IMLNs, we analyzed the proportion of the volume that received 45 Gy, the proportion of the volume that received 25 Gy, the dose to 95% of the volume, the dose to 50% of the volume, the mean dose, the minimum dose (Dmin), and the maximum dose (Dmax). Results: Left-sided treatments predominated in the 3D cohort. There were no differences between the 2D and 3D cohorts regarding tumor stage, type of surgery (mastectomy, breast-conserving surgery, or mastectomy with immediate reconstruction), or mean delineated IMLN volume (6.8 vs. 5.9 mL; p = 0.411). Except for the Dmin, all dosimetric parameters presented higher mean values in the 3D cohort (p < 0.05). The median Dmax in the 3D cohort was 50.34 Gy. However, the mean dose to the IMLNs was 7.93 Gy in the 2D cohort, compared with 20.64 Gy in the 3D cohort. Conclusion: Neither technique delivered enough doses to the IMLNs to achieve subclinical disease control. However, all of the dosimetric parameters were significantly higher for the 3D technique. (author)

  6. Three-dimensional electron-beam dose calculations

    International Nuclear Information System (INIS)

    Shiu, A.S.

    1988-01-01

    The MDAH pencil-beam algorithm developed by Hogstrom et al (1981) has been widely used in clinics for electron-beam dose calculations for radiotherapy treatment planning. The primary objective of this research was to address several deficiencies of that algorithm and to develop an enhanced version. Two enhancements were incorporated into the pencil-beam algorithm; one models fluence rather than planar fluence, and the other models the bremsstrahlung dose using measured beam data. Comparisons of the resulting calculated dose distributions with measured dose distributions for several test phantoms have been made. From these results it is concluded (1) that the fluence-based algorithm is more accurate to use for the dose calculation in an inhomogeneous slab phantom, and (2) the fluence-based calculation provides only a limited improvement to the accuracy the calculated dose in the region just downstream of the lateral edge of an inhomogeneity. A pencil-beam redefinition model was developed for the calculation of electron-beam dose distributions in three dimensions

  7. Rapid Arc, helical tomotherapy, sliding window intensity modulated radiotherapy and three dimensional conformal radiation for localized prostate cancer: A dosimetric comparison

    Directory of Open Access Journals (Sweden)

    Rajesh A Kinhikar

    2014-01-01

    Full Text Available Objective: The objective of this study was to investigate the potential role of RapidArc (RA compared with helical tomotherapy (HT, sliding window intensity modulated radiotherapy (SW IMRT and three-dimensional conformal radiation therapy (3D CRT for localized prostate cancer. Materials and Methods: Prescription doses ranged from 60 Gy to planning target volume (PTV and 66.25 Gy for clinical target volume prostate (CTV-P over 25-30 fractions. PTV and CTV-P coverage were evaluated by conformity index (CI and homogeneity index (HI. Organ sparing comparison was done with mean doses to rectum and bladder. Results: CI 95 were 1.0 ± 0.01 (RA, 0.99 ± 0.01 (HT, 0.97 ± 0.02 (IMRT, 0.98 ± 0.02 (3D CRT for PTV and 1.0 ± 0.00 (RA, HT, SW IMRT and 3D CRT for CTV-P. HI was 0.11 ± 0.03 (RA, 0.16 ± 0.08 (HT, 0.12 ± 0.03 (IMRT, 0.06 ± 0.01 (3D CRT for PTV and 0.03 ± 0.00 (RA, 0.05 ± 0.01 (HT, 0.03 ± 0.01 (SW IMRT and 3D CRT for CTV-P. Mean dose to bladder were 23.68 ± 13.23 Gy (RA, 24.55 ± 12.51 Gy (HT, 19.82 ± 11.61 Gy (IMRT and 23.56 ± 12.81 Gy (3D CRT, whereas mean dose to rectum was 36.85 ± 12.92 Gy (RA, 33.18 ± 11.12 Gy (HT, IMRT and 38.67 ± 12.84 Gy (3D CRT. Conclusion: All studied intensity-modulated techniques yield treatment plans of significantly improved quality when compared with 3D CRT, with HT providing best organs at risk sparing and RA being the most efficient treatment option, reducing treatment time to 1.45-3.7 min and monitor unit to <400 for a 2 Gy fraction.

  8. Conformal symmetry in two-dimensional space: recursion representation of conformal block

    International Nuclear Information System (INIS)

    Zamolodchikov, A.B.

    1988-01-01

    The four-point conformal block plays an important part in the analysis of the conformally invariant operator algebra in two-dimensional space. The behavior of the conformal block is calculated in the present paper in the limit in which the dimension Δ of the intermediate operator tends to infinity. This makes it possible to construct a recursion relation for this function that connects the conformal block at arbitrary Δ to the blocks corresponding to the dimensions of the zero vectors in the degenerate representations of the Virasoro algebra. The relation is convenient for calculating the expansion of the conformal block in powers of the uniformizing parameters q = i π tau

  9. Evaluation of Geometrically Optimized Single- and Double-plane Interstitial High Dose Rate Implants with Respect to Conformality and Homogeneity

    International Nuclear Information System (INIS)

    Major, Tibor; Polgar, Csaba; Fodor, Janos; Takacsi-nagy, Zoltan; Mangel, Laszlo; Nemeth, Gyoergy

    2003-01-01

    The use of a stepping source in high dose rate brachytherapy supported with dwell-time optimization makes it possible to deviate from the classical dosimetry systems. Dose distributions of single- and double-plane implants were analysed for conformality and homogeneity at idealized target volumes. The Paris system was used for catheter positioning and target volume determination. Geometric optimization and individual dose prescription were applied. Volumetric indices and dose parameters were calculated at optimal active length, which was found to be equal to target volume length. The mean conformality, homogeneity, external volume and overdose volume indices were 0.78, 0.67, 0.22 and 0.13, respectively. The average minimum target and reference doses were 69% and 86%, respectively. Comparisons between the volumetric indices of geometrical optimized and non-optimized implants were also performed, and a significant difference was found regarding any index. The geometrical optimization resulted in superior conformality and slightly inferior homogeneity. At geometrically optimized implants, the active length can be reduced compared to non-optimized implants. Volumetric parameters and dose-volume histogram-based individual dose prescription are recommended for quantitative assessment of interstitial implants

  10. Postoperative Chemotherapy Followed by Conformal Concomitant Chemoradiotherapy in High-Risk Gastric Cancer

    International Nuclear Information System (INIS)

    Quero, Laurent; Bouchbika, Zineb; Kouto, Honorine; Baruch-Hennequin, Valerie; Gornet, Jean-Marc; Munoz, Nicolas; Cojean-Zelek, Isabelle; Houdart, Remi; Panis, Yves; Valleur, Patrice; Aparicio, Thomas; Maylin, Claude; Hennequin, Christophe

    2012-01-01

    Purpose: To analyze the efficacy, toxicity, and pattern of relapse after adjuvant cisplatin-based chemotherapy followed by three-dimensional irradiation and concomitant LV5FU2 chemotherapy (high-dose leucovorin and 5-fluorouracil bolus plus continuous infusion) in the treatment of completely resected high-risk gastric cancer. Methods and Materials: This was a retrospective analysis of 52 patients with high-risk gastric cancer initially treated by total/partial gastrectomy and lymphadenectomy between January 2002 and June 2007. Median age was 54 years (range, 36–75 years). Postoperative treatment consisted of 5-fluorouracil and cisplatin chemotherapy. Adjuvant chemotherapy was followed by three-dimensional conformal radiotherapy in the tumor bed and regional lymph nodes at 4500 cGy/25 fractions in association with concomitant chemotherapy. Concomitant chemotherapy consisted of a 2-h infusion of leucovorin (200 mg/m²) followed by a bolus of 5-fluorouracil (400 mg/m²) and then a 44-h continuous infusion of 5-fluorouracil (2400–3600 mg/m²) given every 14 days, for three cycles (LV5FU2 protocol). Results: Five-year overall and disease-free survival were 50% and 48%, respectively. Distant metastases and peritoneal spread were the most frequent sites of relapse (37% each). After multivariate analysis, only pathologic nodal status was significantly associated with disease-free and overall survival. Acute toxicities were essentially gastrointestinal and hematologic. One myocardial infarction and one pulmonary embolism were also reported. Eighteen patients had a radiotherapy program interruption because of acute toxicity. All patients but 2 have completed radiotherapy. Conclusion: Postoperative cisplatin-based chemotherapy followed by conformal radiotherapy in association with concurrent 5-fluorouracil seemed to be feasible and resulted in successful locoregional control.

  11. Chronic rectal bleeding after high dose conformal treatment of prostate cancer warrants modification of existing morbidity scales

    International Nuclear Information System (INIS)

    Hanlon, A.L.; Schulthiess, T.E.; Hunt, M.A.; Movsas, B.; Peter, R.; Hanks, G.E.

    1996-01-01

    Purpose: Serious late morbidity (Grade (3(4))) from the conformal treatment of prostate cancer has been reported in <1% to 6% of patients. This study demonstrates that the reported frequency of Grade (3(4)) complications varies by the morbidity scale selected and that no existing morbidity scale adequately represents chronic rectal bleeding, which is our most frequent persisting late sequela of high dose conformal treatment. Materials and Methods: Between (5(89)) and (12(93)), 352 patients with T1-3 NXM0 prostate cancers were treated with our 4-field conformal technique without special rectal blocking. This technique includes a 1 cm margin from the CTV to the PTV in all directions. The median follow-up for these patients was 38 mos (4 to 78), and the median ICRU reporting point dose was 74 Gy (63 to 81). Patients are followed at six month intervals, and no patient is lost to follow-up. Three morbidity scales are assessed, the RTOG, the late effects group (LENT), and our modification of the LENT (FC-LENT). This modification registers chronic rectal bleeding requiring more than two coagulations as a grade 3 event. Estimates for Grade (3(4)) late GI complication rates were determined using Kaplan-Meier methodology. Differences in morbidity rates were evaluated using the log-rank test and differences in time to latency of complications were evaluated using the nonparametric Wilcoxon test. The duration of severe symptoms with chronic rectal bleeding is measured from the first to the last transrectal coagulation. Results: Sixteen patients developed Grade (3(4)) complications by one of the three morbidity scales. Two patients required surgery (colostomy, sigmoid resection), 5 required a transfusion, and 9 required more than two coagulations. The median latency to the third coagulation (plus or minus transfusions) was 24 mos (17 to 40). The median duration of bleeding between the first and last coagulation was 6 mos (3 to 25), illustrating the chronicity of this problem

  12. Superintegrability of d-dimensional conformal blocks

    International Nuclear Information System (INIS)

    Isachenkov, Mikhail

    2016-02-01

    We observe that conformal blocks of scalar 4-point functions in a d-dimensional conformal field theory can mapped to eigenfunctions of a 2-particle hyperbolic Calogero-Sutherland Hamiltonian. The latter describes two coupled Poeschl-Teller particles. Their interaction, whose strength depends smoothly on the dimension d, is known to be superintegrable. Our observation enables us to exploit the rich mathematical literature on Calogero-Sutherland models in deriving various results for conformal field theory. These include an explicit construction of conformal blocks in terms of Heckman-Opdam hypergeometric functions and a remarkable duality that relates the blocks of theories in different dimensions.

  13. Superintegrability of d-dimensional conformal blocks

    Energy Technology Data Exchange (ETDEWEB)

    Isachenkov, Mikhail [Weizmann Institute of Science, Rehovot (Israel). Dept. of Particle Physics and Astronomy; Schomerus, Volker [DESY Theory Group, Hamburg (Germany)

    2016-02-15

    We observe that conformal blocks of scalar 4-point functions in a d-dimensional conformal field theory can mapped to eigenfunctions of a 2-particle hyperbolic Calogero-Sutherland Hamiltonian. The latter describes two coupled Poeschl-Teller particles. Their interaction, whose strength depends smoothly on the dimension d, is known to be superintegrable. Our observation enables us to exploit the rich mathematical literature on Calogero-Sutherland models in deriving various results for conformal field theory. These include an explicit construction of conformal blocks in terms of Heckman-Opdam hypergeometric functions and a remarkable duality that relates the blocks of theories in different dimensions.

  14. Results of Three-Dimensional Conformal Radiation Therapy for the Treatment of a Solitary Sternal Relapse of Breast Cancer

    International Nuclear Information System (INIS)

    Kim, Hae Young; Huh, Seung Jae; Park, Won; Choi, Do Ho; Kang, Min Kyu; Yang, Jung Hyun; Nam, Seok Jin; Im, Young Hyuck

    2008-01-01

    To evaluate the response and survival rate after three-dimensional conformal radiation therapy (3D-CRT) of patients with a solitary sternal relapse of breast cancer. Seventeen patients between May 1996 and June 2005 were evaluated with the salvage 3D-CRT treatment of a solitary sternal relapse of breast cancer. The treatment fields included the gross tumor volume with 2 cm margins. The total radiation dose was 35.0 ∼61.5 Gy (biologic effective dose of 43.7 ∼76.9 Gy10 using an α/β ratio of 10 Gy), with a daily dose of 1.8∼3.0 Gy. The tumor response was evaluated by the change in maximum tumor size via follow up CT scans 1∼3 months after the completion of treatment. An objective tumor response was achieved in all patients, with a complete response in 5 patients and a partial response in 12 patients. The 5-year overall survival rate was 51.9% (median survival time: 27 months), and the most important factor affecting overall survival was the disease-free interval (interval from primary surgery of breast cancer to the development of sternal metastasis): The 5-year overall survival rate was 61.8% for patients with a disease-free interval ≥12 months and 0.0% for patients < with disease-free interval <12 months (p=0.03). The response to 3D-CRT was good in patients with solitary sternal relapse of breast cancer. Particularly, patients with long disease-free interval from primary surgery survived significantly longer than patients with short disease-free interval from primary surgery

  15. Interim report of image-guided conformal high-dose-rate brachytherapy for patients with unfavorable prostate cancer: the William Beaumont Phase II dose-escalating trial

    International Nuclear Information System (INIS)

    Martinez, Alvaro A.; Kestin, Larry L.; Stromberg, Jannifer S.; Gonzalez, Jose A.; Wallace, Michelle; Gustafson, Gary S.; Edmundson, Gregory K.; Spencer, William; Vicini, Frank A.

    2000-01-01

    Purpose: We analyzed our institution's experience treating patients with unfavorable prostate cancer in a prospective Phase II dose-escalating trial of external beam radiation therapy (EBRT) integrated with conformal high-dose-rate (HDR) brachytherapy boosts. This interim report discusses treatment outcome and prognostic factors using this treatment approach. Methods and Materials: From November 1991 through February 1998, 142 patients with unfavorable prostate cancer were prospectively treated in a dose-escalating trial with pelvic EBRT in combination with outpatient HDR brachytherapy at William Beaumont Hospital. Patients with any of the following characteristics were eligible: pretreatment prostate-specific antigen (PSA) ≥ 10.0 ng/ml, Gleason score ≥ 7, or clinical stage T2b or higher. All patients received pelvic EBRT to a median total dose of 46.0 Gy. Pelvic EBRT was integrated with ultrasound-guided transperineal conformal interstitial iridium-192 HDR implants. From 1991 to 1995, 58 patients underwent three conformal interstitial HDR implants during the first, second, and third weeks of pelvic EBRT. After October 1995, 84 patients received two interstitial implants during the first and third weeks of pelvic EBRT. The dose delivered via interstitial brachytherapy was escalated from 5.50 Gy to 6.50 Gy for each implant in those patients receiving three implants, and subsequently, from 8.25 Gy to 9.50 Gy per fraction in those patients receiving two implants. To improve implant quality and reduce operator dependency, an on-line, image-guided interactive dose optimization program was utilized during each HDR implant. No patient received hormonal therapy unless treatment failure was documented. The median follow-up was 2.1 years (range: 0.2-7.2 years). Biochemical failure was defined according to the American Society for Therapeutic Radiology and Oncology Consensus Panel definition. Results: The pretreatment PSA level was ≥ 10.0 ng/ml in 51% of patients. The

  16. Dose modeling of noninvasive image-guided breast brachytherapy in comparison to electron beam boost and three-dimensional conformal accelerated partial breast irradiation.

    Science.gov (United States)

    Sioshansi, Shirin; Rivard, Mark J; Hiatt, Jessica R; Hurley, Amanda A; Lee, Yoojin; Wazer, David E

    2011-06-01

    To perform dose modeling of a noninvasive image-guided breast brachytherapy (NIIGBB) for comparison to electrons and 3DCRT. The novel technology used in this study is a mammography-based, noninvasive breast brachytherapy system whereby the treatment applicators are centered on the planning target volume (PTV) to direct (192)Ir emissions along orthogonal axes. To date, three-dimensional dose modeling of NIIGBB has not been possible because of the limitations of conventional treatment planning systems (TPS) to model variable tissue deformation associated with breast compression. In this study, the TPS was adapted such that the NIIGBB dose distributions were modeled as a virtual point source. This dose calculation technique was applied to CT data from 8 patients imaged with the breast compressed between parallel plates in the cranial-caudal and medial-lateral axes. A dose-volume comparison was performed to simulated electron boost and 3DCRT APBI. The NIIGBB PTV was significantly reduced as compared with both electrons and 3DCRT. Electron boost plans had a lower D(min) than the NIIGBB technique but higher V(100), D(90), and D(50). With regard to PTV coverage for APBI, the only significant differences were minimally higher D(90), D(100), V(80), and V(90), with 3DCRT and D(max) with NIIGBB. The NIIGBB technique, as compared with electrons and 3D-CRT, achieved a lower maximum dose to skin (60% and 10%, respectively) and chest wall/lung (70-90%). NIIGBB achieves a PTV that is smaller than electron beam and 3DCRT techniques. This results in significant normal tissue sparing while maintaining dosimetric benchmarks to the target tissue. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Modelling normal tissue isoeffect distribution in conformal radiotherapy of glioblastoma provides an alternative dose escalation pattern through hypofractionation without reducing the total dose

    International Nuclear Information System (INIS)

    Mangel, L.; Skriba, Z.; Major, T.; Polgar, C.; Fodor, J.; Somogyi, A.; Nemeth, G.

    2002-01-01

    The purpose of this study was to prove that by using conformal external beam radiotherapy (RT) normal brain structures can be protected even when applying an alternative approach of biological dose escalation: hypofractionation (HOF) without total dose reduction (TDR). Traditional 2-dimensional (2D) and conformal 3-dimensional (3D) treatment plans were prepared for 10 gliomas representing the subanatomical sites of the supratentorial brain. Isoeffect distributions were generated by the biologically effective dose (BED) formula to analyse the effect of conventionally fractionated (CF) and HOF schedules on both the spatial biological dose distribution and biological dose-volume histograms. A comparison was made between 2D-CF (2.0 Gy/day) and 3D-HOF (2.5 Gy/day) regimens, applying the same 60 Gy total doses. Integral biologically effective dose (IBED) and volumes received biologically equivalent to a dose of 54 Gy or more (V-BED54) were calculated for the lower and upper brain stem as organs of risk. The IBED values were lower with the 3D-HOF than with the 2D-CF schedule in each tumour location, means 22.7±17.1 and 40.4±16.9 in Gy, respectively (p<0.0001). The V-BED54 values were also smaller or equal in 90% of the cases favouring the 3D-HOF scheme. The means were 2.7±4.8 ccm for 3D-HOF and 10.7±12.7 ccm for 2D-CF (p=0.0006). Our results suggest that with conformal RT, fraction size can gradually be increased. HOF radiotherapy regimens without TDR shorten the treatment time and seem to be an alternative way of dose escalation in the treatment of glioblastoma

  18. Modelling normal tissue isoeffect distribution in conformal radiotherapy of glioblastoma provides an alternative dose escalation pattern through hypofractionation without reducing the total dose

    Energy Technology Data Exchange (ETDEWEB)

    Mangel, L.; Skriba, Z.; Major, T.; Polgar, C.; Fodor, J.; Somogyi, A.; Nemeth, G. [National Research Inst. for Radiobiology and Radiohygiene, Budapest (Hungary)

    2002-04-01

    The purpose of this study was to prove that by using conformal external beam radiotherapy (RT) normal brain structures can be protected even when applying an alternative approach of biological dose escalation: hypofractionation (HOF) without total dose reduction (TDR). Traditional 2-dimensional (2D) and conformal 3-dimensional (3D) treatment plans were prepared for 10 gliomas representing the subanatomical sites of the supratentorial brain. Isoeffect distributions were generated by the biologically effective dose (BED) formula to analyse the effect of conventionally fractionated (CF) and HOF schedules on both the spatial biological dose distribution and biological dose-volume histograms. A comparison was made between 2D-CF (2.0 Gy/day) and 3D-HOF (2.5 Gy/day) regimens, applying the same 60 Gy total doses. Integral biologically effective dose (IBED) and volumes received biologically equivalent to a dose of 54 Gy or more (V-BED54) were calculated for the lower and upper brain stem as organs of risk. The IBED values were lower with the 3D-HOF than with the 2D-CF schedule in each tumour location, means 22.7{+-}17.1 and 40.4{+-}16.9 in Gy, respectively (p<0.0001). The V-BED54 values were also smaller or equal in 90% of the cases favouring the 3D-HOF scheme. The means were 2.7{+-}4.8 ccm for 3D-HOF and 10.7{+-}12.7 ccm for 2D-CF (p=0.0006). Our results suggest that with conformal RT, fraction size can gradually be increased. HOF radiotherapy regimens without TDR shorten the treatment time and seem to be an alternative way of dose escalation in the treatment of glioblastoma.

  19. CT-guided intracavitary radiotherapy for cervical cancer: Comparison of conventional point A plan with clinical target volume-based three-dimensional plan using dose-volume parameters

    International Nuclear Information System (INIS)

    Shin, Kyung Hwan; Kim, Tae Hyun; Cho, Jung Keun; Kim, Joo-Young; Park, Sung Yong; Park, Sang-Yoon; Kim, Dae Yong; Chie, Eui Kyu; Pyo, Hong Ryull; Cho, Kwan Ho

    2006-01-01

    2.15, respectively. Statistical analysis showed that the conformal index and external volume index improved significantly with the CTV plan, and this improvement was more marked in Group 1. The mean values of the bladder and rectal point doses and volume fractions receiving 50%, 80%, and 100% of the reference dose did not differ between plans for all patients. The reduction in the mean rectal and bladder point doses and irradiated volumes for the CTV plan was statistically significant in Group 1. Conclusion: Computed tomography-guided CTV planning of ICR is superior to conventional point A planning in terms of conformity of target coverage and avoidance of overdosed normal tissue volume. To ascertain the potential benefit of treatment outcome, ICR with image-guided three-dimensional plans will be pursued and correlated with the dose-volume parameters

  20. Strategies to evaluate the impact of rectal volume on prostate motion during three-dimensional conformal radiotherapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Poli, Ana Paula Diniz Fortuna, E-mail: anapaulafortuna@yahoo.com.br [Universidade Estadual de Campinas (CAISM/UNICAMP), Campinas, SP (Brazil). Centro de Atencao Integrada a Saude da Mulher. Divisao de Radioterapia; Dias, Rodrigo Souza; Giordani, Adelmo Jose; Segreto, Helena Regina Comodo; Segreto, Roberto Araujo [Universidade Federal de Sao Paulo (EPM/UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina. Divisao de Radioterapia

    2016-01-15

    Objective: To evaluate the rectal volume influence on prostate motion during three-dimensional conformal radiotherapy (3D-CRT) for prostate cancer. Materials and Methods: Fifty-one patients with prostate cancer underwent a series of three computed tomography scans including an initial planning scan and two subsequent scans during 3D-CRT. The organs of interest were outlined. The prostate contour was compared with the initial CT images considering the anterior, posterior, superior, inferior and lateral edges of the organ. Variations in the anterior limits and volume of the rectum were assessed and correlated with prostate motion in the anteroposterior direction. Results: The maximum range of prostate motion was observed in the superoinferior direction, followed by the anteroposterior direction. A significant correlation was observed between prostate motion and rectal volume variation (p = 0.037). A baseline rectal volume superior to 70 cm{sup 3} had a significant influence on the prostate motion in the anteroposterior direction (p = 0.045). Conclusion: The present study showed a significant interfraction motion of the prostate during 3D-CRT with greatest variations in the superoinferior and anteroposterior directions, and that a large rectal volume influences the prostate motion with a cutoff value of 70 cm{sup 3}. Therefore, the treatment of patients with a rectal volume > 70 cm{sup 3} should be re-planned with appropriate rectal preparation. Keywords: Rectal volume; Prostate cancer; Three-dimensional conformal radiotherapy. (author)

  1. Curvature invariant characterization of event horizons of four-dimensional black holes conformal to stationary black holes

    Science.gov (United States)

    McNutt, David D.

    2017-11-01

    We introduce three approaches to generate curvature invariants that transform covariantly under a conformal transformation of a four-dimensional spacetime. For any black hole conformally related to a stationary black hole, we show how a set of conformally covariant invariants can be combined to produce a conformally covariant invariant that detects the event horizon of the conformally related black hole. As an application we consider the rotating dynamical black holes conformally related to the Kerr-Newman-Unti-Tamburino-(anti)-de Sitter spacetimes and construct an invariant that detects the conformal Killing horizon along with a second invariant that detects the conformal stationary limit surface. In addition, we present necessary conditions for a dynamical black hole to be conformally related to a stationary black hole and apply these conditions to the ingoing Kerr-Vaidya and Vaidya black hole solutions to determine if they are conformally related to stationary black holes for particular choices of the mass function. While two of the three approaches cannot be generalized to higher dimensions, we discuss the existence of a conformally covariant invariant that will detect the event horizon for any higher dimensional black hole conformally related to a stationary black hole which admits at least two conformally covariant invariants, including all vacuum spacetimes.

  2. Later Outcomes and Alpha/Beta Estimate From Hypofractionated Conformal Three-Dimensional Radiotherapy Versus Standard Fractionation for Localized Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Leborgne, Felix [Department of Radiation Oncology, Hospital Italiano, Montevideo (Uruguay); Fowler, Jack, E-mail: jackfowlersbox@gmail.com [Department of Human Oncology, University of Wisconsin Medical School, Madison, WI (United States); Leborgne, Jose H.; Mezzera, Julieta [Department of Radiation Oncology, Hospital Italiano, Montevideo (Uruguay)

    2012-03-01

    Purpose: Now that the follow-up time has exceeded 5 years, an estimate of the {alpha}/{beta} ratio can be presented. The additional late outcomes in patients treated with three-dimensional conformal external beam radiotherapy for localized prostate cancer using a hypofractionated vs. a standard fractionation regimen are reported from this prospective nonrandomized contemporary comparison. Methods and Materials: A total of 114 nonrandomized patients chose hypofractionation delivered in 20 fractions of 3 Gy or 3.15 Gy (mean 3.06 Gy) for localized prostate cancer within a median overall time of 32 days (range, 29-49) using four fractions weekly. A total of 160 comparable patients were contemporarily treated within a median of 55 days (range 49-66). The median follow-up was 66 months (range, 24-95) for the hypofractionated arm and 63 months (range, 36-92) for the standard arm. The percentage of patients in the low-, medium-, and high-risk groups was 36%, 46%, and 18% in the hypofractionated arm and 44%, 50%, and 6% in standard arm (2 Gy), respectively. Results: The 5-year actuarial biochemical absence of disease (prostate-specific antigen nadir + 2 ng/mL) and disease-free survival rate was the same at 89% in both arms, making the {alpha}/{beta} calculation unambiguous. The point ratio of {alpha}/{beta} was 1.86 (95% confidence interval, 0.7-5.1 Gy). The 95% confidence interval was determined entirely by the binomial confidence limits in the numbers of patients. Rectal reactions of grade 3 and 4 occurred in 1 of 114 (hypofractionated) and 2 of 160 (standard) patients. Conclusions: The presented three-dimensional conformal regimen was acceptable, and the {alpha}/{beta} value was 1.8, in agreement with other very recent low meta-analyses (reviewed in the '' section).

  3. Predictors of radiation-induced esophageal toxicity in patients with non-small-cell lung cancer treated with three-dimensional conformal radiotherapy

    International Nuclear Information System (INIS)

    Singh, Anurag K.; Lockett, Mary Ann; Bradley, Jeffrey D.

    2003-01-01

    Purpose: To evaluate the incidence and clinical/dosimetric predictors of acute and late Radiation Therapy Oncology Group Grade 3-5 esophageal toxicity in patients with non-small-cell lung cancer (NSCLC) treated with definitive three-dimensional conformal radiotherapy (3D-CRT). Methods and Materials: We retrospectively reviewed the charts of 207 consecutive patients with NSCLC who were treated with high-dose, definitive 3D-CRT between March 1991 and December 1998. This population consisted of 107 men and 100 women. The median age was 67 years (range 31-90). The following patient and treatment parameters were studied: age, gender, race, performance status, sequential chemotherapy, concurrent chemotherapy, presence of subcarinal nodes, pretreatment weight loss, mean dose to the entire esophagus, maximal point dose to the esophagus, and percentage of volume of esophagus receiving >55 Gy. All doses are reported without heterogeneity corrections. The median prescription dose to the isocenter in this population was 70 Gy (range 60-74) delivered in 2-Gy daily fractions. All patients were treated once daily. Acute and late esophageal toxicities were graded by Radiation Therapy Oncology Group criteria. Patient and clinical/dosimetric factors were coded and correlated with acute and late Grade 3-5 esophageal toxicity using univariate and multivariate regression analyses. Results: Of 207 patients, 16 (8%) developed acute (10 patients) or late (13 patients) Grade 3-5 esophageal toxicity. Seven patients had both acute and late Grade 3-5 esophageal toxicity. One patient died (Grade 5 esophageal toxicity) of late esophageal perforation. Concurrent chemotherapy, maximal point dose to the esophagus >58 Gy, and a mean dose to the entire esophagus >34 Gy were significantly associated with a risk of Grade 3-5 esophageal toxicity on univariate analysis. Concurrent chemotherapy and maximal point dose to the esophagus >58 Gy retained significance on multivariate analysis. Of 207 patients

  4. Motion-Compensated Estimation of Delivered Dose during External BeamRadiation Therapy: Implementation in Philips’ Pinnacle3 Treatment Planning System

    NARCIS (Netherlands)

    Bharat, S.; Parikh, P.; Noel, C.; Meltsner, M.; Bzdusek, K.; Kaus, M.

    2012-01-01

    Purpose: Recent research efforts investigating dose escalation techniques for three-dimensional conformal radiation therapy (3D CRT) andintensity modulated radiation therapy (IMRT) have demonstrated great benefit when high-dose hypofractionated treatment schemes are implemented16,21. The use of

  5. Results of induction chemotherapy followed by three-dimensional conformal radiotherapy and concurrent weekly paclitaxel for stage III non-small cell lung cancer

    International Nuclear Information System (INIS)

    Wang Weihua; Bao Yong; Chen Ming; Zhang Li; Xu Guangchuan; Li Kaixin

    2008-01-01

    Objective: To evaluate the toxicity and efficacy of induction chemotherapy (ICT) followed by three-dimensional conformal radiotherapy (3DCRT) plus concurrent weekly paclitaxel for inoperable non-small cell lung cancer (NSCLC). Methods: Patients with stage III NSCLC in favorable conditions were treated with 2 to 4 cycles of carboplatin (AUC=5-6, d1) combined with paclitaxel (175 mg/m 2 , d1), then followed by weekly paclitaxel (40 mg/m 2 ) and concurrent 3DCRT within 34 weeks. The prescription dose of radiotherapy was given as high as possible while total lung V 20 ≤31% and total dose of the spinal cord ≤50 Gy. Results: ICT was well tolerated. During the concurrent chemoradiotherapy,the treatment of 4 patients was ended ahead of the schedule because of severe pulmonary and cardiac toxicities; the treatment of 2 patients was delayed for 7 and 12 days because of fatigue. Leucopenia(33/56) was in grade 1-2 except 1 patient in grade 3. Lymphocytopenia was severe (54/56,42 in grade 3). Three patients developed grade 3 acute radiation-induced esophagitis, and 3 developed grade 3-4 radiation-induced pneumonitis. There was one patients each who developed grade 2,3, and 4 late esophageal damage, respectively. Nine developed grade 2 pulmonary fibrosis. The overall response rate was 69.7%. The 1-year overall survival rate was 72.3%. The 1-year local progression-free survival rate was 62.7%. Conclusions: The schedule of ICT followed by weekly paclitaxel and concurrent 3DCRT can be well tolerated by most of the favorable patients with stage III NSCLC, and the toxicity is tolerable. Results of this study are encouraging, though long-term results should be followed up. (authors)

  6. Dose escalation of radical radiation therapy in non-small-cell lung cancer using positron emission tomography/computed tomography-defined target volumes: Are class solutions obsolete?

    International Nuclear Information System (INIS)

    Everitt, S.; Schneider-Kolsky, M.; Budd, R.; Yuen, K.; Manus, M Mac

    2008-01-01

    Full text: This study investigated the maximum theoretical radiation dose that could safely be delivered to 20 patients diagnosed with non-small-cell lung cancer. Two three-dimensional conformal radiation therapy (RT) class-solution techniques (A and B) and an individualized three-dimensional conformal RT technique (C) were compared at the standard dose of 60 Gy (part I). Dose escalation was then attempted for each technique successfully at 60 Gy, constrained by predetermined limits for lung and spinal canal (part II). Part I and part II data were reanalysed to include oesophageal dose constraints (part III). In part I, 60 Gy was successfully planned using techniques A, B and C in 19 (95%), 18 (90%) and 20 (100%) patients, respectively. The mean escalated dose attainable for part II using techniques A, B and C were 76.4, 74 and 97.8 Gy, respectively (P < 0.0005). One (5%) patient was successfully planned for 120 Gy using techniques A and B, whereas four (20%) were successfully planned using technique C. Following the inclusion of additional constraints applied to the oesophagus in part III, the amount of escalated dose remained the same for all patients who were successfully planned at 60 Gy apart from two patients when technique C was applied. In conclusion, individualized three-dimensional conformal RT facilitated greater dose conformation and higher escalation of dose in most patients. With modern planning tools, simple class solutions are obsolete for conventional dose radical RT in non-small-cell lung cancer. Highly individualized conformal planning is essential for dose escalation.

  7. Long-term results of high-dose conformal radiotherapy for patients with medically inoperable T1-3N0 non-small-cell lung cancer: Is low incidence of regional failure due to incidental nodal irradiation?

    International Nuclear Information System (INIS)

    Chen Ming; Hayman, James A.; Haken, Randall K. ten; Tatro, Daniel; Fernando, Shaneli; Kong, F.-M.

    2006-01-01

    Purpose: To report the results of high-dose conformal irradiation and examine incidental nodal irradiation and nodal failure in patients with inoperable early-stage non-small-cell lung cancer (NSCLC). Methods and Materials: This analysis included patients with inoperable CT-staged T1-3N0M0 NSCLC treated on our prospective dose-escalation trial. Patients were treated with radiation alone (total dose, 63-102.9 Gy in 2.1-Gy daily fractions) with a three-dimensional conformal technique without intentional nodal irradiation. Bilateral highest mediastinal and upper/lower paratracheal, prevascular and retrotracheal, sub- and para-aortic, subcarinal, paraesophageal, and ipsilateral hilar regions were delineated individually. Nodal failure and doses of incidental irradiation were studied. Results: The potential median follow-up was 104 months. For patients who completed protocol treatment, median survival was 31 months. The actuarial overall survival rate was 86%, 61%, 43%, and 21% and the cause-specific survival rate was 89%, 70%, 53%, and 35% at 1, 2, 3, and 5 years, respectively. Weight loss (p = 0.008) and radiation dose in Gy (p = 0.013) were significantly associated with overall survival. In only 22% and 13% of patients examined did ipsilateral hilar and paratracheal (and subaortic for left-sided tumor) nodal regions receive a dose of ≥40 Gy, respectively. Less than 10% of all other nodal regions received a dose of ≥40 Gy. No patients failed initially at nodal sites. Conclusions: Radiation dose is positively associated with overall survival in patients with medically inoperable T1-3N0 NSCLC, though long-term results remain poor. The nodal failure rate is low and does not seem to be due to high-dose incidental irradiation

  8. A three-dimensional Dirichlet-to-Neumann operator for water waves over topography

    Science.gov (United States)

    Andrade, D.; Nachbin, A.

    2018-06-01

    Surface water waves are considered propagating over highly variable non-smooth topographies. For this three dimensional problem a Dirichlet-to-Neumann (DtN) operator is constructed reducing the numerical modeling and evolution to the two dimensional free surface. The corresponding Fourier-type operator is defined through a matrix decomposition. The topographic component of the decomposition requires special care and a Galerkin method is provided accordingly. One dimensional numerical simulations, along the free surface, validate the DtN formulation in the presence of a large amplitude, rapidly varying topography. An alternative, conformal mapping based, method is used for benchmarking. A two dimensional simulation in the presence of a Luneburg lens (a particular submerged mound) illustrates the accurate performance of the three dimensional DtN operator.

  9. A custom three-dimensional electron bolus technique for optimization of postmastectomy irradiation

    International Nuclear Information System (INIS)

    Perkins, George H.; McNeese, Marsha D.; Antolak, John A.; Buchholz, Thomas A.; Strom, Eric A.; Hogstrom, Kenneth R.

    2001-01-01

    Purpose: Postmastectomy irradiation (PMI) is a technically complex treatment requiring consideration of the primary tumor location, possible risk of internal mammary node involvement, varying chest wall thicknesses secondary to surgical defects or body habitus, and risk of damaging normal underlying structures. In this report, we describe the application of a customized three-dimensional (3D) electron bolus technique for delivering PMI. Methods and Materials: A customized electron bolus was designed using a 3D planning system. Computed tomography (CT) images of each patient were obtained in treatment position and the volume to be treated was identified. The distal surface of the wax bolus matched the skin surface, and the proximal surface was designed to conform to the 90% isodose surface to the distal surface of the planning target volume (PTV). Dose was calculated with a pencil-beam algorithm correcting for patient heterogeneity. The bolus was then fabricated from modeling wax using a computer-controlled milling device. To aid in quality assurance, CT images with the bolus in place were generated and the dose distribution was computed using these images. Results: This technique optimized the dose distribution while minimizing irradiation of normal tissues. The use of a single anterior field eliminated field junction sites. Two patients who benefited from this option are described: one with altered chest wall geometry (congenital pectus excavatum), and one with recurrent disease in the medial chest wall and internal mammary chain (IMC) area. Conclusion: The use of custom 3D electron bolus for PMI is an effective method for optimizing dose delivery. The radiation dose distribution is highly conformal, dose heterogeneity is reduced compared to standard techniques in certain suboptimal settings, and excellent immediate outcome is obtained

  10. Single-arc volumetric-modulated arc therapy (sVMAT) as adjuvant treatment for gastric cancer: Dosimetric comparisons with three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT)

    International Nuclear Information System (INIS)

    Wang, Xin; Li, Guangjun; Zhang, Yingjie; Bai, Sen; Xu, Feng; Wei, Yuquan; Gong, Youling

    2013-01-01

    To compare the dosimetric differences between the single-arc volumetric-modulated arc therapy (sVMAT), 3-dimensional conformal radiotherapy (3D-CRT), and intensity-modulated radiotherapy (IMRT) techniques in treatment planning for gastric cancer as adjuvant radiotherapy. Twelve patients were retrospectively analyzed. In each patient's case, the parameters were compared based on the dose-volume histogram (DVH) of the sVMAT, 3D-CRT, and IMRT plans, respectively. Three techniques showed similar target dose coverage. The maximum and mean doses of the target were significantly higher in the sVMAT plans than that in 3D-CRT plans and in the 3D-CRT/IMRT plans, respectively, but these differences were clinically acceptable. The IMRT and sVMAT plans successfully achieved better target dose conformity, reduced the V 20/30 , and mean dose of the left kidney, as well as the V 20/30 of the liver, compared with the 3D-CRT plans. And the sVMAT technique reduced the V 20 of the liver much significantly. Although the maximum dose of the spinal cord were much higher in the IMRT and sVMAT plans, respectively (mean 36.4 vs 39.5 and 40.6 Gy), these data were still under the constraints. Not much difference was found in the analysis of the parameters of the right kidney, intestine, and heart. The IMRT and sVMAT plans achieved similar dose distribution to the target, but superior to the 3D-CRT plans, in adjuvant radiotherapy for gastric cancer. The sVMAT technique improved the dose sparings of the left kidney and liver, compared with the 3D-CRT technique, but showed few dosimetric advantages over the IMRT technique. Studies are warranted to evaluate the clinical benefits of the VMAT treatment for patients with gastric cancer after surgery in the future

  11. Three-dimensional teletherapy treatment planning

    International Nuclear Information System (INIS)

    Panthaleon van Eck, R.B. van.

    1986-01-01

    This thesis deals with physical/mathematical backgrounds of computerized teletherapy treatment planning. The subjects discussed in this thesis can be subdivided into three main categories: a) Three-dimensional treatment planning. A method is evaluated which can be used for the purpose of simulation and optimization of dose distributions in three dimensions. b) The use of Computed Tomography. The use of patient information obtained from Computed Tomography for the purpose of dose computations is evaluated. c) Dose computational models for photon- and electron beams. Models are evaluated which provide information regarding the way in which the radiation dose is distributed in the patient (viz. is absorbed and/or dispersed). (Auth.)

  12. Predictors of grade {>=}2 and grade {>=}3 radiation pneumonitis in patients with locally advanced non-small cell lung cancer treated with three-dimensional conformal radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Dang, Jun; Li, Guang; Ma, Lianghua; Han, Chong; Zhang, Shuo; Yao, Lei [Dept. of Radiation Oncology, The First Hospital of China Medical Univ., Shenyang (China)], e-mail: gl1963516@yahoo.cn; Diao, Rao [Dept. of Experimental Technology Center, China Medical Univ., Shenyang (China); Zang, Shuang [Dept. of Nursing, China Medical Univ., Shenyang (China)

    2013-08-15

    Grade {>=}3 radiation pneumonitis (RP) is generally severe and life-threatening. Predictors of grade {>=}2 are usually used for grade {>=}3 RP prediction, but it is unclear whether these predictors are appropriate. In this study, predictors of grade {>=}2 and grade {>=}3 RP were investigated separately. The increased risk of severe RP in elderly patients compared with younger patients was also evaluated. Material and methods: A total of 176 consecutive patients with locally advanced non-small cell lung cancer were followed up prospectively after three-dimensional conformal radiotherapy. RP was graded according to Common Terminology Criteria for Adverse Events version 3.0. Results: Mean lung dose (MLD), mean heart dose, ratio of planning target volume to total lung volume (PTV/Lung), and dose-volume histogram comprehensive value of both heart and lung were associated with both grade {>=}2 and grade {>=}3 RP in univariate analysis. In multivariate logistic regression analysis, age and MLD were predictors of both grade {>=}2 RP and grade {>=}3 RP; receipt of chemotherapy predicted grade {>=}3 RP only; and sex and PTV/Lung predicted grade {>=}2 RP only. Among patients who developed high-grade RP, MLD and PTV/Lung were significantly lower in patients aged {>=}70 years than in younger patients (p<0.05 for both comparisons). Conclusions: The predictors were not completely consistent between grade {>=}2 RP and grade {>=}3 RP. Elderly patients had a higher risk of severe RP than younger patients did, possibly due to lower tolerance of radiation to the lung.

  13. Induction chemotherapy plus three-dimensional conformal radiation therapy in the definitive treatment of locally advanced non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Sim, Sang; Rosenzweig, Kenneth E.; Schindelheim, Rachel; Ng, Kenneth K.; Leibel, Steven A.

    2001-01-01

    Purpose: To evaluate our institution's experience using chemotherapy in conjunction with three-dimensional conformal radiation therapy (3D-CRT). Methods and Materials: From 1991 to 1998, 152 patients with Stage III non-small-cell lung cancer (NSCLC) were treated with 3D-CRT at Memorial Sloan-Kettering Cancer Center. A total of 137 patients (90%) were surgically staged with either thoracotomy or mediastinoscopy. The remainder were staged radiographically. Seventy patients were treated with radiation therapy alone, and 82 patients received induction chemotherapy before radiation. The majority of chemotherapy-treated patients received a platinum-containing regimen. Radiation was delivered with a 3D conformal technique using CT-based treatment planning. The median dose in the radiation alone group was 70.2 Gy, while in the combined modality group, it was 64.8 Gy. Results: The median follow-up time was 30.5 months among survivors. Stage IIIB disease was present in 36 patients (51%) in the radiation-alone group and 57 patients (70%) in the combined-modality group. Thirty-nine patients had poor prognostic factors (KPS 5%), and they were equally distributed between the two groups. The median survival times for the radiation-alone and the combined-modality groups were 11.7 months and 18.1 months, respectively (p=0.001). The 2-year rates of local control in the radiation-alone and combined-modality groups were 35.4% and 43.1%, respectively (p=0.1). Grade 3 or worse nonhematologic toxicity occurred in 20% of the patients receiving radiation alone and in 16% of those receiving chemotherapy and radiation. Overall, there were only 4 cases of Grade 3 or worse esophagitis. Conclusion: Despite more Stage IIIB patients in the combined-modality group, the addition of chemotherapy to 3D-CRT produced a survival advantage over 3D-CRT alone in Stage III NSCLC without a concomitant increase in toxicity. Chemotherapy thus appears to be beneficial, even in patients who are receiving higher

  14. Three-dimensional dose distribution in contrast-enhanced digital mammography using Gafchromic XR-QA2 films: Feasibility study

    International Nuclear Information System (INIS)

    Hwang, Yi-Shuan; Lin, Yu-Ying; Cheung, Yun-Chung; Tsai, Hui-Yu

    2014-01-01

    This study was aimed to establish three-dimensional dose distributions for contrast-enhanced digital mammography (CEDM) using self-developed Gafchromic XR-QA2 films. Dose calibration and distribution evaluations were performed on a full-field digital mammography unit with dual energy (DE) contrast-enhanced option. Strategy for dose calibration of films in the DE mode was based on the data obtained from common target/filter/kVp combinations used clinically and the dose response model modified from Rampado's model. Dose derived from films were also verified by measured data from an ionization chamber. The average difference of dose was 8.9% in the dose range for clinical uses. Three-dimensional dose distributions were estimated using triangular acrylic phantom equipped with the mammography system. Five pieces of film sheets were separately placed between the acrylic slabs to evaluate the dose distribution at different depths. After normalizing the dose in each pixel to the maximum dose at the top-center position of the acrylic, normalized dose distribution for transverse, coronal and sagittal planes, could thus be obtained. The depth dose distribution evaluated in this study may further serve as a reference for evaluating the patient glandular dose at different depths based on the entrance exposure information. - Highlights: • CEDM techniques can enhance contrast uptake areas and suppress background tissue. • Dose for the dual-energy acquisition is about 20% higher than standard mode. • A new method is proposed to estimate the 3D dose distribution in dual-energy CEDM. • Depth of normalized dose ratio of 0.5 is less than but near 1 cm in the DE mode

  15. Effect of Concurrent High-Dose Cisplatin Chemotherapy and Conformal Radiotherapy on Cervical Esophageal Cancer Survival

    International Nuclear Information System (INIS)

    Huang Shaohui; Lockwood, Gina; Brierley, James; Cummings, Bernard; Kim, John; Wong, Rebecca; Bayley, Andrew; Ringash, Jolie

    2008-01-01

    Purpose: To determine whether a change in treatment policy to conformal, elective nodal radiotherapy and concurrent high-dose cisplatin improved survival for cervical esophageal cancer patients. Methods and Materials: All cervical esophageal cancer patients treated between 1997 and 2005 were restaged (1983 American Joint Committee on Cancer criteria). Patients treated before 2001 (previous cohort [PC]) were compared with those treated from 2001 onward (recent cohort [RC]). The PC institutional chemoradiotherapy protocol was 54 Gy in 20 fractions within 4 weeks, with 5-fluorouracil (1,000 mg/m 2 ) on Days 1-4 and either mitomycin C (10 mg/m 2 ) or cisplatin (75 mg/m 2 ) on Day 1. The RC institutional chemoradiotherapy protocol was conformal radiotherapy, 70 Gy in 35 fractions within 7 weeks, to the primary tumor and elective nodes, with high-dose cisplatin (100 mg/m 2 ) on Days 1, 22, and 43. Results: The median follow-up was 3.1 years (PC, 8.1 and RC, 2.3). Of 71 patients (25 women and 46 men), 21 of 29 in the PC and 29 of 42 in the RC were treated curatively (curative subgroup, n = 50). Between the two groups, no differences in overall survival or locoregional relapse-free survival were seen. The overall survival rate at 2 and 5 years was 35% (range, 24-47%) and 21% (range, 12-32%) in the whole group and 46% (range 32-60%) and 28% (range, 15-42%) in the curative group, respectively. In the curative group, no statistically significant prognostic factors were found. Trends toward better locoregional relapse-free survival were seen in women (2-year rate, 73% vs. for men, 36%; p = 0.08) and in patients aged >64 years (2-year rate, 68% vs. age ≤64 years, 34%; p = 0.10). Conclusion: No survival improvement could be demonstrated after changing the treatment policy to high-dose cisplatin-based, conventionally fractionated conformal chemoradiotherapy. Female gender and older age might predict for better outcomes

  16. Metastatic breast cancer in the eye and orbit, use three-dimensional conformal radiotherapy. Our first experience

    International Nuclear Information System (INIS)

    Correa Pablos, Tamara; Caceres Toledo, Maria

    2009-01-01

    The eye and orbit metastases are a significant clinical problem, both by the inability and the deterioration in the quality of life that occur. The most common malignant tumors in the eye and orbit is metastasis. Cancer breast cancer is the most common tumor metastatic to the eye and orbit in a 40% and 50% of cases according to different series. With the introduction of Three-Dimensional Conformal Radiotherapy (3D-CRT) in our hospital from In 2007 we were able to treat patients with cancer different regions with the technique (2D) was impossible because caused irreparable damage to surrounding healthy tissue in this way thanks to potential of 3D technology to shape the planning volume will ensure greater protection for critical organs. (Author)

  17. Definition of the supraclavicular and infraclavicular nodes: implications for three-dimensional CT-based conformal radiation therapy.

    Science.gov (United States)

    Madu, C N; Quint, D J; Normolle, D P; Marsh, R B; Wang, E Y; Pierce, L J

    2001-11-01

    To delineate with computed tomography (CT) the anatomic regions containing the supraclavicular (SCV) and infraclavicular (IFV) nodal groups, to define the course of the brachial plexus, to estimate the actual radiation dose received by these regions in a series of patients treated in the traditional manner, and to compare these doses to those received with an optimized dosimetric technique. Twenty patients underwent contrast material-enhanced CT for the purpose of radiation therapy planning. CT scans were used to study the location of the SCV and IFV nodal regions by using outlining of readily identifiable anatomic structures that define the nodal groups. The brachial plexus was also outlined by using similar methods. Radiation therapy doses to the SCV and IFV were then estimated by using traditional dose calculations and optimized planning. A repeated measures analysis of covariance was used to compare the SCV and IFV depths and to compare the doses achieved with the traditional and optimized methods. Coverage by the 90% isodose surface was significantly decreased with traditional planning versus conformal planning as the depth to the SCV nodes increased (P correlation was found between brachial plexus depth and SCV depth up to 7 cm. Conformal optimized planning provided improved dosimetric coverage compared with standard techniques.

  18. The three-dimensional origin of the classifying algebra

    International Nuclear Information System (INIS)

    Fuchs, Juergen; Schweigert, Christoph; Stigner, Carl

    2010-01-01

    It is known that reflection coefficients for bulk fields of a rational conformal field theory in the presence of an elementary boundary condition can be obtained as representation matrices of irreducible representations of the classifying algebra, a semisimple commutative associative complex algebra. We show how this algebra arises naturally from the three-dimensional geometry of factorization of correlators of bulk fields on the disk. This allows us to derive explicit expressions for the structure constants of the classifying algebra as invariants of ribbon graphs in the three-manifold S 2 xS 1 . Our result unravels a precise relation between intertwiners of the action of the mapping class group on spaces of conformal blocks and boundary conditions in rational conformal field theories.

  19. Conformal Radiotherapy: Physics, Treatment Planning and Verification. Proceedings book

    Energy Technology Data Exchange (ETDEWEB)

    De Wagter, C [ed.

    1995-12-01

    The goal of conformal radiotherapy is to establish radiation dose distributions that conform tightly to the target volume in view of limiting radiation to normal tissues. Conformal radiotherapy significantly improves both local control and palliation and thus contributes to increase survival and to improve the quality of life. The subjects covered by the symposium include : (1) conformal radiotherapy and multi-leaf collimation; (2) three dimensional imaging; (3) treatment simulation, planning and optimization; (4) quality assurance; and (5) dosimetry. The book of proceedings contains the abstracts of the invited lectures, papers and poster presentations as well as the full papers of these contributions.

  20. Conformal Radiotherapy: Physics, Treatment Planning and Verification. Proceedings book

    International Nuclear Information System (INIS)

    De Wagter, C.

    1995-12-01

    The goal of conformal radiotherapy is to establish radiation dose distributions that conform tightly to the target volume in view of limiting radiation to normal tissues. Conformal radiotherapy significantly improves both local control and palliation and thus contributes to increase survival and to improve the quality of life. The subjects covered by the symposium include : (1) conformal radiotherapy and multi-leaf collimation; (2) three dimensional imaging; (3) treatment simulation, planning and optimization; (4) quality assurance; and (5) dosimetry. The book of proceedings contains the abstracts of the invited lectures, papers and poster presentations as well as the full papers of these contributions

  1. Pulmonary Toxicity in Stage III Non-Small Cell Lung Cancer Patients Treated With High-Dose (74 Gy) 3-Dimensional Conformal Thoracic Radiotherapy and Concurrent Chemotherapy Following Induction Chemotherapy: A Secondary Analysis of Cancer and Leukemia Group B (CALGB) Trial 30105

    International Nuclear Information System (INIS)

    Salama, Joseph K.; Stinchcombe, Thomas E.; Gu Lin; Wang Xiaofei; Morano, Karen; Bogart, Jeffrey A.; Crawford, Jeffrey C.; Socinski, Mark A.; Blackstock, A. William; Vokes, Everett E.

    2011-01-01

    Purpose: Cancer and Leukemia Group B (CALGB) 30105 tested two different concurrent chemoradiotherapy platforms with high-dose (74 Gy) three-dimensional conformal radiotherapy (3D-CRT) after two cycles of induction chemotherapy for Stage IIIA/IIIB non–small cell lung cancer (NSCLC) patients to determine if either could achieve a primary endpoint of >18-month median survival. Final results of 30105 demonstrated that induction carboplatin and gemcitabine and concurrent gemcitabine 3D-CRT was not feasible because of treatment-related toxicity. However, induction and concurrent carboplatin/paclitaxel with 74 Gy 3D-CRT had a median survival of 24 months, and is the basis for the experimental arm in CALGB 30610/RTOG 0617/N0628. We conducted a secondary analysis of all patients to determine predictors of treatment-related pulmonary toxicity. Methods and Materials: Patient, tumor, and treatment-related variables were analyzed to determine their relation with treatment-related pulmonary toxicity. Results: Older age, higher N stage, larger planning target volume (PTV)1, smaller total lung volume/PTV1 ratio, larger V20, and larger mean lung dose were associated with increasing pulmonary toxicity on univariate analysis. Multivariate analysis confirmed that V20 and nodal stage as well as treatment with concurrent gemcitabine were associated with treatment-related toxicity. A high-risk group comprising patients with N3 disease and V20 >38% was associated with 80% of Grades 3-5 pulmonary toxicity cases. Conclusions: Elevated V20 and N3 disease status are important predictors of treatment related pulmonary toxicity in patients treated with high-dose 3D-CRT and concurrent chemotherapy. Further studies may use these metrics in considering patients for these treatments.

  2. Pulmonary Toxicity in Stage III Non-Small Cell Lung Cancer Patients Treated With High-Dose (74 Gy) 3-Dimensional Conformal Thoracic Radiotherapy and Concurrent Chemotherapy Following Induction Chemotherapy: A Secondary Analysis of Cancer and Leukemia Group B (CALGB) Trial 30105

    Energy Technology Data Exchange (ETDEWEB)

    Salama, Joseph K., E-mail: joseph.salama@duke.edu [Duke University Medical Center, Durham, NC (United States); Stinchcombe, Thomas E. [University of North Carolina at Chapel Hill, Chapel Hill, NC (United States); Gu Lin; Wang Xiaofei [CALGB Statistical Center, Duke University Medical Center, Durham, NC (United States); Morano, Karen [Quality Assurance Review Center, Lincoln, RI (United States); Bogart, Jeffrey A. [State University of New York Upstate Medical University, Syracuse, NY (United States); Crawford, Jeffrey C. [Duke University Medical Center, Durham, NC (United States); Socinski, Mark A. [University of North Carolina at Chapel Hill, Chapel Hill, NC (United States); Blackstock, A. William [Wake Forest University School of Medicine, Winston-Salem, NC (United States); Vokes, Everett E. [University of Chicago, Chicago, IL (United States)

    2011-11-15

    Purpose: Cancer and Leukemia Group B (CALGB) 30105 tested two different concurrent chemoradiotherapy platforms with high-dose (74 Gy) three-dimensional conformal radiotherapy (3D-CRT) after two cycles of induction chemotherapy for Stage IIIA/IIIB non-small cell lung cancer (NSCLC) patients to determine if either could achieve a primary endpoint of >18-month median survival. Final results of 30105 demonstrated that induction carboplatin and gemcitabine and concurrent gemcitabine 3D-CRT was not feasible because of treatment-related toxicity. However, induction and concurrent carboplatin/paclitaxel with 74 Gy 3D-CRT had a median survival of 24 months, and is the basis for the experimental arm in CALGB 30610/RTOG 0617/N0628. We conducted a secondary analysis of all patients to determine predictors of treatment-related pulmonary toxicity. Methods and Materials: Patient, tumor, and treatment-related variables were analyzed to determine their relation with treatment-related pulmonary toxicity. Results: Older age, higher N stage, larger planning target volume (PTV)1, smaller total lung volume/PTV1 ratio, larger V20, and larger mean lung dose were associated with increasing pulmonary toxicity on univariate analysis. Multivariate analysis confirmed that V20 and nodal stage as well as treatment with concurrent gemcitabine were associated with treatment-related toxicity. A high-risk group comprising patients with N3 disease and V20 >38% was associated with 80% of Grades 3-5 pulmonary toxicity cases. Conclusions: Elevated V20 and N3 disease status are important predictors of treatment related pulmonary toxicity in patients treated with high-dose 3D-CRT and concurrent chemotherapy. Further studies may use these metrics in considering patients for these treatments.

  3. SU-E-T-346: Effect of Jaw Position On Dose to Critical Structures in 3-D Conformal Radiotherapy Treatment of Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Paudel, N; Han, E; Liang, X; Morrill, S; Zhang, X; Hardee, M; Penagaricano, J; Ratanatharathorn, V [Vaneerat, University of Arkansas for Medical Sciences, Little Rock, AR (United States)

    2015-06-15

    Purpose: Three-dimensional conformal therapy remains a valid and widely used modality for pancreatic radiotherapy treatment. It usually meets dose constraints on critical structures. However, careful positioning of collimation jaws can reduce dose to the critical structures. Here we investigate the dosimetric effect of jaw position in MLC-based 3-D conformal treatment planning on critical structures. Methods: We retrospectively selected seven pancreatic cancer patients treated with 3-D conformal radiotherapy. We started with treatment plans (Varian Truebeam LINAC, Eclipse TPS, AAA, 18MV) having both x and y jaws aligned with the farthest extent of the block outline (8mm around PTV). Then we subsequently moved either both x-jaws or all x and y jaws outwards upto 3 cm in 1 cm increments and investigated their effect on average and maximum dose to neighboring critical structures keeping the same coverage to treatment volume. Results: Lateral displacement of both x-jaws by 1cm each increased kidney and spleen mean dose by as much as 1.7% and 1.3% respectively and superior inferior displacement increased liver, right kidney, stomach and spleen dose by as much as 2.1%, 2%, 5.2% and 1.6% respectively. Displacement of all x and y-jaws away by 1cm increased the mean dose to liver, right kidney, left kidney, bowels, cord, stomach and spleen by as much as 4.9%, 5.9%, 2.1%, 2.8%, 7.4%, 10.4% and 4.2% respectively. Percentage increase in mean dose due to 2 and 3cm jaw displacement increased almost linearly with the displaced distance. Changes in maximum dose were much smaller (mostly negligible) than the changes in mean dose. Conclusion: Collimation jaw position affects dose mostly to critical structures adjacent to it. Though treatment plans with MLCs conforming the block margin usually meet dose constraints to critical structures, keeping jaws all the way in, to the edge of the block reduces dose to the critical structures during radiation treatment.

  4. Extracranial stereotactic radiotherapy: Evaluation of PTV coverage and dose conformity

    International Nuclear Information System (INIS)

    Haedinger, U.; Thiele, W.; Wulf, J.

    2002-01-01

    During the past few years the concept of cranial sterotactic radiotherapy has been successfully extended to extracranial tumoral targets. In our department, hypofractionated treatment of tumours in lung, liver, abdomen, and pelvis is performed in the Stereotactic Body Frame (ELEKTA Instrument AB) since 1997. We present the evaluation of 63 consecutively treated targets (22 lung, 21 liver, 20 abdomen/pelvis) in 58 patients with respect to dose coverage of the planning target volume (PTV) as well as conformity of the dose distribution. The mean PTV coverage was found to be 96.3%±2.3% (lung), 95.0%±4.5% (liver), and 92.1%±5.2% (abdomen/pelvis). For the so-called conformation number we obtained values of 0.73±0.09 (lung), 0.77±0.10 (liver), and 0.70±0.08 (abdomen/pelvis). The results show that highly conformal treatment techniques can be applied also in extracranial stereotactic radiotherapy. This is primarily due to the relatively simple geometrical shape of most of the targets. Especially lung and liver targets turned out to be approximately spherically/cylindrically shaped, so that the dose distribution can be easily tailored by rotational fields. (orig.) [de

  5. Experience of micromultileaf collimator linear accelerator based single fraction stereotactic radiosurgery: Tumor dose inhomogeneity, conformity, and dose fall off

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Linda X.; Garg, Madhur; Lasala, Patrick; Kim, Mimi; Mah, Dennis; Chen, Chin-Cheng; Yaparpalvi, Ravindra; Mynampati, Dinesh; Kuo, Hsiang-Chi; Guha, Chandan; Kalnicki, Shalom [Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Neurosurgery, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Epidemiology and Population Health, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States); Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, New York 10461 (United States)

    2011-03-15

    Purpose: Sharp dose fall off outside a tumor is essential for high dose single fraction stereotactic radiosurgery (SRS) plans. This study explores the relationship among tumor dose inhomogeneity, conformity, and dose fall off in normal tissues for micromultileaf collimator (mMLC) linear accelerator (LINAC) based cranial SRS plans. Methods: Between January 2007 and July 2009, 65 patients with single cranial lesions were treated with LINAC-based SRS. Among them, tumors had maximum diameters {<=}20 mm: 31; between 20 and 30 mm: 21; and >30 mm: 13. All patients were treated with 6 MV photons on a Trilogy linear accelerator (Varian Medical Systems, Palo Alto, CA) with a tertiary m3 high-resolution mMLC (Brainlab, Feldkirchen, Germany), using either noncoplanar conformal fixed fields or dynamic conformal arcs. The authors also created retrospective study plans with identical beam arrangement as the treated plan but with different tumor dose inhomogeneity by varying the beam margins around the planning target volume (PTV). All retrospective study plans were normalized so that the minimum PTV dose was the prescription dose (PD). Isocenter dose, mean PTV dose, RTOG conformity index (CI), RTOG homogeneity index (HI), dose gradient index R{sub 50}-R{sub 100} (defined as the difference between equivalent sphere radius of 50% isodose volume and prescription isodose volume), and normal tissue volume (as a ratio to PTV volume) receiving 50% prescription dose (NTV{sub 50}) were calculated. Results: HI was inversely related to the beam margins around the PTV. CI had a ''V'' shaped relationship with HI, reaching a minimum when HI was approximately 1.3. Isocenter dose and mean PTV dose (as percentage of PD) increased linearly with HI. R{sub 50}-R{sub 100} and NTV{sub 50} initially declined with HI and then reached a plateau when HI was approximately 1.3. These trends also held when tumors were grouped according to their maximum diameters. The smallest tumor group

  6. Computerized three-dimensional treatment planning system utilizing interactive colour graphics

    Energy Technology Data Exchange (ETDEWEB)

    McShan, D L; Silverman, A; Lanza, D M; Reinstein, L E; Glicksman, A S [Rhode Island Hospital (US). Dept. of Radiation Oncology

    1979-06-01

    A new computerized radiation treatment planning system has been developed to aid in three-dimensional treatment planning. Using interactive colour graphics in conjunction with a PDP 11/45 computer, the system can take multiple transverse contours and construct a perspective display of the treatment region showing organ surfaces as well as cross-sectional contours. With interactively selected orientations, the display allows easy perception of the relative positioning of the treatment volume and the neighbouring anatomy. For external beam treatment planning, interactive computer simulation is used to select diaphragm sizes which best conform to the target area while avoiding sensitive structures. Dose calculations for the selected beams are carried out on multiple transverse planes. The calculational planes and surfaces are displayed in perspective with radiation dosage displayed in an interactively manipulated colour display. Altogether the system provides an easy assessment of the volume to be irradiated, interactive selection of optimal arrangements of treatment fields and a means of visualizing and evaluating the resulting dose distributions.

  7. CFT description of three-dimensional Kerr-de Sitter spacetime

    International Nuclear Information System (INIS)

    Fjelstad, Jens; Hwang, Stephen; Maansson, Teresia

    2002-01-01

    We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space

  8. CFT description of three-dimensional Kerr-de Sitter spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Fjelstad, Jens E-mail: jens.fjelstad@kau.se; Hwang, Stephen E-mail: stephen.hwang@kau.se; Maansson, Teresia E-mail: teresia@physto.se

    2002-10-07

    We describe three-dimensional Kerr-de Sitter space using similar methods as recently applied to the BTZ black hole. A rigorous form of the classical connection between gravity in three dimensions and two-dimensional conformal field theory is employed, where the fundamental degrees of freedom are described in terms of two dependent SL(2,C) currents. In contrast to the BTZ case, however, quantization does not give the Bekenstein-Hawking entropy connected to the cosmological horizon of Kerr-de Sitter space.

  9. Self-organization of a self-assembled supramolecular rectangle, square, and three-dimensional cage on Au111 surfaces.

    Science.gov (United States)

    Yuan, Qun-Hui; Wan, Li-Jun; Jude, Hershel; Stang, Peter J

    2005-11-23

    The structure and conformation of three self-assembled supramolecular species, a rectangle, a square, and a three-dimensional cage, on Au111 surfaces were investigated by scanning tunneling microscopy. These supramolecular assemblies adsorb on Au111 surfaces and self-organize to form highly ordered adlayers with distinct conformations that are consistent with their chemical structures. The faces of the supramolecular rectangle and square lie flat on the surface, preserving their rectangle and square conformations, respectively. The three-dimensional cage also forms well-ordered adlayers on the gold surface, forming regular molecular rows of assemblies. When the rectangle and cage were mixed together, the assemblies separated into individual domains, and no mixed adlayers were observed. These results provide direct evidence of the noncrystalline solid-state structures of these assemblies and information about how they self-organize on Au111 surfaces, which is of importance in the potential manufacturing of functional nanostructures and devices.

  10. Changes in Pulmonary Function After Three-Dimensional Conformal Radiotherapy, Intensity-Modulated Radiotherapy, or Proton Beam Therapy for Non-Small-Cell Lung Cancer

    International Nuclear Information System (INIS)

    Lopez Guerra, Jose L.; Gomez, Daniel R.; Zhuang Yan; Levy, Lawrence B.; Eapen, George; Liu, Hongmei; Mohan, Radhe; Komaki, Ritsuko; Cox, James D.; Liao Zhongxing

    2012-01-01

    Purpose: To investigate the extent of change in pulmonary function over time after definitive radiotherapy for non-small-cell lung cancer (NSCLC) with modern techniques and to identify predictors of changes in pulmonary function according to patient, tumor, and treatment characteristics. Patients and Methods: We analyzed 250 patients who had received ≥60 Gy radio(chemo)therapy for primary NSCLC in 1998–2010 and had undergone pulmonary function tests before and within 1 year after treatment. Ninety-three patients were treated with three-dimensional conformal radiotherapy, 97 with intensity-modulated radiotherapy, and 60 with proton beam therapy. Postradiation pulmonary function test values were evaluated among individual patients compared with the same patient’s preradiation value at the following time intervals: 0–4 (T1), 5–8 (T2), and 9–12 (T3) months. Results: Lung diffusing capacity for carbon monoxide (DLCO) was reduced in the majority of patients along the three time periods after radiation, whereas the forced expiratory volume in 1 s per unit of vital capacity (FEV1/VC) showed an increase and decrease after radiation in a similar percentage of patients. There were baseline differences (stage, radiotherapy dose, concurrent chemotherapy) among the radiation technology groups. On multivariate analysis, the following features were associated with larger posttreatment declines in DLCO: pretreatment DLCO, gross tumor volume, lung and heart dosimetric data, and total radiation dose. Only pretreatment DLCO was associated with larger posttreatment declines in FEV1/VC. Conclusions: Lung diffusing capacity for carbon monoxide is reduced in the majority of patients after radiotherapy with modern techniques. Multiple factors, including gross tumor volume, preradiation lung function, and dosimetric parameters, are associated with the DLCO decline. Prospective studies are needed to better understand whether new radiation technology, such as proton beam therapy

  11. Investigation of conformal and intensity-modulated radiation therapy techniques to determine the absorbed fetal dose in pregnant patients with breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Öğretici, Akın, E-mail: akinogretici@gmail.com; Akbaş, Uğur; Köksal, Canan; Bilge, Hatice

    2016-07-01

    The aim of this research was to investigate the fetal doses of pregnant patients undergoing conformal radiotherapy or intensity-modulated radiation therapy (IMRT) for breast cancers. An Alderson Rando phantom was chosen to simulate a pregnant patient with breast cancer who is receiving radiation therapy. This phantom was irradiated using the Varian Clinac DBX 600 system (Varian Medical System, Palo Alto, CA) linear accelerator, according to the standard treatment plans of both three-dimensional conformal radiation therapy (3-D CRT) and IMRT techniques. Thermoluminescent dosimeters were used to measure the irradiated phantom's virtually designated uterus area. Thermoluminescent dosimeter measurements (in the phantom) revealed that the mean cumulative fetal dose for 3-D CRT is 1.39 cGy and for IMRT it is 8.48 cGy, for a pregnant breast cancer woman who received radiation treatment of 50 Gy. The fetal dose was confirmed to increase by 70% for 3-D CRT and 40% for IMRT, if it is closer to the irradiated field by 5 cm. The mean fetal dose from 3-D CRT is 1.39 cGy and IMRT is 8.48 cGy, consistent with theoretic calculations. The IMRT technique causes the fetal dose to be 5 times more than that of 3-D CRT. Theoretic knowledge concerning the increase in the peripheral doses as the measurements approached the beam was also practically proven.

  12. Three-dimensional radiation treatment planning

    International Nuclear Information System (INIS)

    Mohan, R.

    1989-01-01

    A major aim of radiation therapy is to deliver sufficient dose to the tumour volume to kill the cancer cells while sparing the nearby health organs to prevent complications. With the introduction of devices such as CT and MR scanners, radiation therapy treatment planners have access to full three-dimensional anatomical information to define, simulate, and evaluate treatments. There are a limited number of prototype software systems that allow 3D treatment planning currently in use. In addition, there are more advanced tools under development or still in the planning stages. They require sophisticated graphics and computation equipment, complex physical and mathematical algorithms, and new radiation treatment machines that deliver dose very precisely under computer control. Components of these systems include programs for the identification and delineation of the anatomy and tumour, the definition of radiation beams, the calculation of dose distribution patterns, the display of dose on 2D images and as three dimensional surfaces, and the generation of computer images to verify proper patient positioning in treatment. Some of these functions can be performed more quickly and accurately if artificial intelligence or expert systems techniques are employed. 28 refs., figs

  13. Ultrasound-guided high dose rate conformal brachytherapy boost in prostate cancer: treatment description and preliminary results of a phase I/II clinical trial

    Energy Technology Data Exchange (ETDEWEB)

    Stromberg, Jannifer; Martinez, Alvaro; Gonzalez, Jose; Edmundson, Gregory; Ohanian, Neshan; Vicini, Frank; Hollander, Jay; Gustafson, Gary; Spencer, William; Di, Yan; Brabbins, Donald

    1995-08-30

    Purpose: To improve results for locally advanced prostate cancer, a prospective clinical trial of concurrent external beam irradiation and fractionated iridium-192 (Ir-192) high dose rate (HDR) conformal boost brachytherapy was initiated. Methods and Materials: Between November 1991 and February 1994, 99 implants were performed on 33 patients with prostatic adenocarcinoma at William Beaumont Hospital. Using AJCC staging criteria, 9 patients had T2b tumors, 17 patients had T2c tumors, and 7 patients had T3 disease. Patients were treated with (a) 45.6 Gy whole pelvis external irradiation and (b) three HDR fractions of 5.5 Gy each (18 patients) or 6 Gy each (15 patients) to the prostate. Transperineal needle implants using real-time ultrasound guidance with interactive on-line isodose distributions were performed on an outpatient basis during weeks 1, 2, and 3 of external irradiation. Acute toxicity was scored using the Radiation Therapy Oncology Group (RTOG) morbidity grading system. Results: This technique of concurrent external pelvic irradiation and conformal HDR brachytherapy was well tolerated. No significant intraoperative or perioperative complications occurred. Three patients (9%) experienced Grade 3 acute toxicity (two dysuria and one diarrhea). All toxicities were otherwise Grades 1 or 2 and were primarily as expected from pelvic external irradiation. Persistent implant-related toxicities included Grades 1-2 perineal pain (12%) and hematospermia (15%). Median follow-up time was 13 months. Serum prostatic-specific antigen (PSA) levels normalized in 91% of patients (29 out of 32) within 1-14 months (median 2.8 months) after irradiation. PSA levels were progressively decreasing in the other three patients at last measurement. Prospectively planned prostatic rebiopsies done at 18 months in the first 10 patients were negative in 9 out of 10 (90%). Conclusions: Acute toxicity has been acceptable with this unique approach using conformal high dose rate Ir-192

  14. Characterization of highly anisotropic three-dimensionally nanostructured surfaces

    International Nuclear Information System (INIS)

    Schmidt, Daniel

    2014-01-01

    Generalized ellipsometry, a non-destructive optical characterization technique, is employed to determine geometrical structure parameters and anisotropic dielectric properties of highly spatially coherent three-dimensionally nanostructured thin films grown by glancing angle deposition. The (piecewise) homogeneous biaxial layer model approach is discussed, which can be universally applied to model the optical response of sculptured thin films with different geometries and from diverse materials, and structural parameters as well as effective optical properties of the nanostructured thin films are obtained. Alternative model approaches for slanted columnar thin films, anisotropic effective medium approximations based on the Bruggeman formalism, are presented, which deliver results comparable to the homogeneous biaxial layer approach and in addition provide film constituent volume fraction parameters as well as depolarization or shape factors. Advantages of these ellipsometry models are discussed on the example of metal slanted columnar thin films, which have been conformally coated with a thin passivating oxide layer by atomic layer deposition. Furthermore, the application of an effective medium approximation approach to in-situ growth monitoring of this anisotropic thin film functionalization process is presented. It was found that structural parameters determined with the presented optical model equivalents for slanted columnar thin films agree very well with scanning electron microscope image estimates. - Highlights: • Summary of optical model strategies for sculptured thin films with arbitrary geometries • Application of the rigorous anisotropic Bruggeman effective medium applications • In-situ growth monitoring of atomic layer deposition on biaxial metal slanted columnar thin film

  15. Dose optimization of intra-operative high dose rate interstitial brachytherapy implants for soft tissue sarcoma

    Directory of Open Access Journals (Sweden)

    Jamema Swamidas

    2009-01-01

    Full Text Available Objective : A three dimensional (3D image-based dosimetric study to quantitatively compare geometric vs. dose-point optimization in combination with graphical optimization for interstitial brachytherapy of soft tissue sarcoma (STS. Materials and Methods : Fifteen consecutive STS patients, treated with intra-operative, interstitial Brachytherapy, were enrolled in this dosimetric study. Treatment plans were generated using dose points situated at the "central plane between the catheters", "between the catheters throughout the implanted volume", at "distances perpendicular to the implant axis" and "on the surface of the target volume" Geometrically optimized plans had dose points defined between the catheters, while dose-point optimized plans had dose points defined at a plane perpendicular to the implant axis and on the target surface. Each plan was graphically optimized and compared using dose volume indices. Results : Target coverage was suboptimal with coverage index (CI = 0.67 when dose points were defined at the central plane while it was superior when the dose points were defined at the target surface (CI=0.93. The coverage of graphically optimized plans (GrO was similar to non-GrO with dose points defined on surface or perpendicular to the implant axis. A similar pattern was noticed with conformity index (0.61 vs. 0.82. GrO were more conformal and less homogeneous compared to non-GrO. Sum index was superior for dose points defined on the surface of the target and relatively inferior for plans with dose points at other locations (1.35 vs. 1.27. Conclusions : Optimization with dose points defined away from the implant plane and on target results in superior target coverage with optimal values of other indices. GrO offer better target coverage for implants with non-uniform geometry and target volume.

  16. Chronic rectal bleeding after high-dose conformal treatment of prostate cancer warrants modification of existing morbidity scales

    International Nuclear Information System (INIS)

    Hanlon, Alexandra L.; Schultheiss, Timothy E.; Hunt, Margie A.; Movsas, Benjamin; Peter, Ruth S.; Hanks, Gerald E.

    1997-01-01

    Purpose: Serious late morbidity (Grade (3(4))) from the conformal treatment of prostate cancer has been reported in <1% to 6% of patients based on existing late gastrointestinal (GI) morbidity scales. None of the existing morbidity scales include our most frequently observed late GI complication, which is chronic rectal bleeding requiring multiple fulgerations. This communication documents the frequency of rectal bleeding requiring multiple fulgerations and illustrates the variation in reported late serious GI complication rates by the selection of morbidity scale. Methods and Materials: Between May 1989 and December 1993, 352 patients with T1-T3 nonmetastatic prostate cancers were treated with our four-field conformal technique without special rectal blocking. This technique includes a 1-cm margin from the clinical target volume (CTV) to the planning target volume (PTV) in all directions. The median follow-up for these patients was 36 months (range 2-76), and the median center of prostate dose was 74 Gy (range 63-81). Three morbidity scales are assessed: the Radiation Therapy Oncology Group (RTOG), the Late Effects Normal Tissue Task Force (LENT), and our modification of the LENT (FC-LENT). This modification registers chronic rectal bleeding requiring at least one blood transfusion and/or more than two coagulations as a Grade 3 event. Estimates for Grade (3(4)) late GI complication rates were determined using Kaplan-Meier methodology. The duration of severe symptoms with chronic rectal bleeding is measured from the first to the last transrectal coagulation. Latency is measured from the end of radiotherapy to surgery, first blood transfusion, or third coagulation procedure. Results: Sixteen patients developed Grade (3(4)) complications by one of the three morbidity scales. Two patients required surgery (colostomy or sigmoid resection), three required multiple blood transfusions, two required one or two blood transfusions, and nine required at least three

  17. Towards multidimensional radiotherapy (MD-CRT): biological imaging and biological conformality

    International Nuclear Information System (INIS)

    Ling, C. Clifton; Humm, John; Larson, Steven; Amols, Howard; Fuks, Zvi; Leibel, Steven; Koutcher, Jason A.

    2000-01-01

    Purpose: The goals of this study were to survey and summarize the advances in imaging that have potential applications in radiation oncology, and to explore the concept of integrating physical and biological conformality in multidimensional conformal radiotherapy (MD-CRT). Methods and Materials: The advances in three-dimensional conformal radiotherapy (3D-CRT) have greatly improved the physical conformality of treatment planning and delivery. The development of intensity-modulated radiotherapy (IMRT) has provided the 'dose painting' or 'dose sculpting' ability to further customize the delivered dose distribution. The improved capabilities of nuclear magnetic resonance imaging and spectroscopy, and of positron emission tomography, are beginning to provide physiological and functional information about the tumor and its surroundings. In addition, molecular imaging promises to reveal tumor biology at the genotype and phenotype level. These developments converge to provide significant opportunities for enhancing the success of radiotherapy. Results: The ability of IMRT to deliver nonuniform dose patterns by design brings to fore the question of how to 'dose paint' and 'dose sculpt', leading to the suggestion that 'biological' images may be of assistance. In contrast to the conventional radiological images that primarily provide anatomical information, biological images reveal metabolic, functional, physiological, genotypic, and phenotypic data. Important for radiotherapy, the new and noninvasive imaging methods may yield three-dimensional radiobiological information. Studies are urgently needed to identify genotypes and phenotypes that affect radiosensitivity, and to devise methods to image them noninvasively. Incremental to the concept of gross, clinical, and planning target volumes (GTV, CTV, and PTV), we propose the concept of 'biological target volume' (BTV) and hypothesize that BTV can be derived from biological images and that their use may incrementally improve

  18. An algebraic approach towards the classification of 2 dimensional conformal field theories

    International Nuclear Information System (INIS)

    Bouwknegt, P.G.

    1988-01-01

    This thesis treats an algebraic method for the construction of 2-dimensional conformal field theories. The method consists of the study of the representation theory of the Virasoro algebra and suitable extensions of this. The classification of 2-dimensional conformal field theories is translated into the classification of combinations of representations which satisfy certain consistence conditions (unitarity and modular invariance). For a certain class of 2-dimensional field theories, namely the one with central charge c = 1 from the theory of Kac-Moody algebra's. there exist indications, but as yet mainly hope, that this construction will finally lead to a classification of 2-dimensional conformal field theories. 182 refs.; 2 figs.; 26 tabs

  19. On-line conformal HDR dose escalation trial in prostate cancer

    International Nuclear Information System (INIS)

    Martinez, Alvaro; Stromberg, Jannifer; Edmundson, Gregory; Gustafson, Gary; Vicini, Frank; Brabbins, Donald

    1996-01-01

    Purpose: To improve treatment results on prostatic adenocarcinoma, we began the first prospective Phase I/II dose-escalating clinical trial of conformal brachytherapy (CB) and concurrent external beam irradiation. Methods and Materials: Fifty-four patients with T2b-T3c prostatic adenocarcinoma received 172 transperineal conformal high-dose rate (HDR) boost implants. All patients received concomitant external beam pelvic irradiation. Dose escalation of the three HDR fractions were: 5.5 Gy (18 patients), 6 Gy (15 patients), and 6.5 Gy (21 patients). The urethra, anterior rectal wall, and prostate boundaries were identified individually and outlined at 5 mm intervals from the base to the apex of the gland. The CB using real-time ultrasound guidance with interactive online isodose distributions was performed on an outpatient basis. As needles were placed into the prostate, corrections for prostate displacement were recorded and the isodose distributions were recalculated to represent the new relationship between the needles, prostate, and normal structures. Results: Craniocaudal motion of the gland ranged from 0.5-2.0 cm (mean=1.0 cm), whereas lateral displacement was 0.1-0.4 cm. With the interactive online planning system, organ motion was immediately detected, accounted for, and corrected prior to each HDR treatment. The rectal dose has ranged from 45 to 87%, and the urethral dose from 97 to 112% of the prostate dose. Negative prostatic biopsies at 18 months were seen in (30(32)) patients. Biochemical (PSA <1.5 ng/ml) control at 36 months is is 89%. It is significant that operator dependence has been completely removed because the interactive online planning system uniformly guides the physicians. Conclusions: With ultrasound guidance and the interactive online dosimetry system, organ motion is insignificant because it can be corrected during the procedure. Common pitfalls of brachytherapy, including operator dependence and difficulty with reproducibility, have been

  20. A comparison of swallowing dysfunction after three-dimensional conformal and intensity-modulated radiotherapy. A systematic review by the Italian Head and Neck Radiotherapy Study Group

    International Nuclear Information System (INIS)

    Ursino, Stefano; Morganti, Riccardo; Cristaudo, Agostino; Paiar, Fabiola; D'Angelo, Elisa; Lohr, Frank; Mazzola, Rosario; Merlotti, Anna; Russi, Elvio Grazioso; Musio, Daniela; Alterio, Daniela; Bacigalupo, Almalina

    2017-01-01

    Dysphagia is one of the most important treatment-related side effects in head and neck cancer (HNC), as it can lead to severe life-threating complications such as aspiration pneumonia and malnutrition. Intensity-modulated radiotherapy (IMRT) could reduce swallowing dysfunction by producing a concave dose distribution and reducing doses to the swallowing-related organs at risk (SWOARs). The aim of this study was to review the current literature in order to compare swallowing outcomes between IMRT and three-dimensional conformal radiotherapy (3DCRT). A search was conducted in the PubMed and Embase databases to identify studies on swallowing outcomes, both clinically and/or instrumentally assessed, after 3DCRT and IMRT. Dysphagia-specific quality of life and objective instrumental data are summarized and discussed. A total of 262 papers were retrieved from the searched databases. An additional 23 papers were retrieved by hand-searching the reference lists. Ultimately, 22 papers were identified which discussed swallowing outcomes after 3DCRT and IMRT for HNC. No outcomes from randomized trials were identified. Despite several methodological limitations, reports from the current literature seem to suggest better swallowing outcomes with IMRT compared to 3DCRT. Further improvements are likely to result from the increased use of IMRT plans optimized for SWOAR sparing. (orig.) [de

  1. Primary observing pulmonary function variety following three-dimensional conformal radiation therapy of III phase non-small cell lung cancer

    International Nuclear Information System (INIS)

    Cai Feng; Li Guang; Zhao Yuxia; Dang Jun; Yao Lei; Wu Chunli

    2006-01-01

    Objective: To explore the pulmonary function, DVH and radiation pneumonitis after three-dimensional conformal radiation treatment of III phase non-small-cell lung cancer. Methods: 71 patients (male 52, female 19, median age 63, KPS≥80) were evaluated by pulmonary function tests before radiotherapy and in M1 and M3 after radiotherapy respectively. After 3 months of follow-up time, it reviewed the appearance and grade of radiation pneumonitis. Then V 20 , V 30 and MLD were worked out from dose volume histogram. Results: All patients completed radiotherapy, and total dose was 66-70 Gy. FVC (L), FEV 1 (L) and C L CO were (2.58±0.65) L, (1.85±0.58) L and (15.15±4.65)ml/(min) before radio- therapy, with(2.96±0.76) L, (2.13±0.65) L and (14.71±3.92) ml/(min) in M1 after radiotherapy, with (2.65±0.61) L, (1.92±0.52) L and (13.15±3.71)ml/(min)in M3 after radiotherapy. The accidence of radiation pneumonitis was 30%, moderate and severe radiation pneumonitis was 7%. With V 20 , V 30 and MLD increasing, the grade of radiation pneumonitis was increasing. V 20 , V 30 and MLD were related to the change in C L CO value among before, M1 and M3 after radiotherapy, and the correlation coefficient was more than 0.2. Conclusions: There is a relationship in the pulmonary fiction, DVH and radiation pneumonitis surely. The change in C L CO value between before radiotherapy and M1 after radiotherapy could predict the radiation pneumonitis. V 20 , V 30 and MLD are not only correlated to radiation pneumonitis evidently but the change in FEV 1 and C L CO after radiotherapy. (authors)

  2. Late rectal toxicity after conformal radiotherapy of prostate cancer (I): multivariate analysis and dose-response

    International Nuclear Information System (INIS)

    Skwarchuk, Mark W.; Jackson, Andrew; Zelefsky, Michael J.; Venkatraman, Ennapadam S.; Cowen, Didier M.; Levegruen, Sabine; Burman, Chandra M.; Fuks, Zvi; Leibel, Steven A.; Ling, C. Clifton

    2000-01-01

    Purpose: The purpose of this paper is to use the outcome of a dose escalation protocol for three-dimensional conformal radiation therapy (3D-CRT) of prostate cancer to study the dose-response for late rectal toxicity and to identify anatomic, dosimetric, and clinical factors that correlate with late rectal bleeding in multivariate analysis. Methods and Materials: Seven hundred forty-three patients with T1c-T3 prostate cancer were treated with 3D-CRT with prescribed doses of 64.8 to 81.0 Gy. The 5-year actuarial rate of late rectal toxicity was assessed using Kaplan-Meier statistics. A retrospective dosimetric analysis was performed for patients treated to 70.2 Gy (52 patients) or 75.6 Gy (119 patients) who either exhibited late rectal bleeding (RTOG Grade 2/3) within 30 months after treatment (i.e., 70.2 Gy--13 patients, 75.6 Gy--36 patients) or were nonbleeding for at least 30 months (i.e., 70.2 Gy--39 patients, 75.6 Gy--83 patients). Univariate and multivariate logistic regression was performed to correlate late rectal bleeding with several anatomic, dosimetric, and clinical variables. Results: A dose response for ≥ Grade 2 late rectal toxicity was observed. By multivariate analysis, the following factors were significantly correlated with ≥ Grade 2 late rectal bleeding for patients prescribed 70.2 Gy: 1) enclosure of the outer rectal contour by the 50% isodose on the isocenter slice (i.e., Iso50) (p max (p max

  3. Three-dimensional determination of absorbed dose by spectrophotometric analysis of ferrous-sulphate agarose gel

    International Nuclear Information System (INIS)

    Gambarini, G.; Gomarasca, G.; Marchesini, R.; Pecci, A.; Pirola, L.; Tomatis, S.

    1999-01-01

    We describe a technique to obtain three-dimensional (3-D) imaging of an absorbed dose by optical transmittance measurements of phantoms composed by agarose gel in which a ferrous sulphate and xylenol orange solution are incorporated. The analysis of gel samples is performed by acquiring transmittance images with a system based on a CCD camera provided with an interference filter matching the optical absorption peak of interest. The proposed technique for 3-D measurements of an absorbed dose is based on the imaging of phantoms composed of sets of properly piled up gel slices. The slice thickness was optimized in order to obtain a good image contrast as well as a good in-depth spatial resolution. To test the technique, a phantom has been irradiated with a collimated γ-beam and then analysed. Proper software was adapted in order to visualise the images of all slices and to attain the 2-D profiles of the dose absorbed by each slice

  4. Estimation of the incidence of late bladder and rectum complications after high-dose (70-78 Gy) conformal radiotherapy for prostate cancer, using dose-volume histograms

    International Nuclear Information System (INIS)

    Boersma, Liesbeth J.; Brink, Mandy van den; Bruce, Allison M.; Shouman, Tarek; Gras, Luuk; Velde, Annet te; Lebesque, Joos V.

    1998-01-01

    Purpose: To investigate whether Dose-Volume Histogram (DVH) parameters can be used to identify risk groups for developing late gastrointestinal (GI) and genitourinary (GU) complications after conformal radiotherapy for prostate cancer. Methods and Materials: DVH parameters were analyzed for 130 patients with localized prostate cancer, treated with conformal radiotherapy in a dose-escalating protocol (70-78 Gy, 2 Gy per fraction). The incidence of late (>6 months) GI and GU complications was classified using the RTOG/EORTC and the SOMA/LENT scoring system. In addition, GI complications were divided in nonsevere and severe (requiring one or more laser treatments or blood transfusions) rectal bleeding. The median follow-up time was 24 months. We investigated whether rectal and bladder wall volumes, irradiated to various dose levels, correlated with the observed actuarial incidences of GI and GU complications, using volume as a continuous variable. Subsequently, for each dose level in the DVH, the rectal wall volumes were dichotomized using different volumes as cutoff levels. The impact of the total radiation dose, and the maximum radiation dose in the rectal and bladder wall was analyzed as well. Results: The actuarial incidence at 2 years for GI complications ≥Grade II was 14% (RTOG/EORTC) or 20% (SOMA/LENT); for GU complications ≥Grade III 8% (RTOG/EORTC) or 21% (SOMA/LENT). Neither for GI complications ≥Grade II (RTOG/EORTC or SOMA/LENT), nor for GU complications ≥Grade III (RTOG/EORTC or SOMA/LENT), was a significant correlation found between any of the DVH parameters and the actuarial incidence of complications. For severe rectal bleeding (actuarial incidence at 2 years 3%), four consecutive volume cutoff levels were found, which significantly discriminated between high and low risk. A trend was observed that a total radiation dose ≥ 74 Gy (or a maximum radiation dose in the rectal wall >75 Gy) resulted in a higher incidence of severe rectal bleeding (p

  5. Three dimensional dose verification for clinical treatments of small intracranial tumours

    International Nuclear Information System (INIS)

    Taylor, M.L.; Dunn, L.; Kairn, L.; Jenny, J.; Knight, R.; Trapp, J.; Smith, R.; Ackerly, T.

    2010-01-01

    Full text: Cancers of the brain and central nervous system account for 1.6% of new cancers and 1.8% of cancer deaths globally. The highest rates of all developed nations are observed in Australia and New Zealand. There are known complexities associated with dose measurement of very small radiation fields. Here, 3D dosimetric verification of treatments for small intracranial tumours using gel dosimetry was investigated. An anthropomorphic head phantom with a 43 mm diameter and 63 mm long gel container was filled with PAGAT normoxic radiosensitive gel. In this work, we show results for a 12-field stereotactic radiotherapy treatment delivered using a Varian 21EX with BrainLAB mini-multi leaf collimator. The gel was read out using an Octopus-1Q laser optical CT scanner. Generally good agreement was observed between the measured doses and those calculated with the iPlan treatment planning system (pencil beam convolution); see Fig. I. For gamma criteria of 5%/5 mm the percentage of gamma values less than unity was 95% above the 80% isodose line, indicating good PTV coverage. For lower isodose regions approaching the boundaries of the container poorer agreement was observed. The feasibility of three-dimensional measurement of small field dose distributions in clinical contexts has been demonstrated. Development of this methodology has the potential to overcome many shortcomings of other dosimetric methods, such as limitations of spatial information (typically one- and two-dimensions), volume-averaging effects and perturbation due to poor mediamatching. (author)

  6. High-resolution three-dimensional mapping of semiconductor dopant potentials

    DEFF Research Database (Denmark)

    Twitchett, AC; Yates, TJV; Newcomb, SB

    2007-01-01

    Semiconductor device structures are becoming increasingly three-dimensional at the nanometer scale. A key issue that must be addressed to enable future device development is the three-dimensional mapping of dopant distributions, ideally under "working conditions". Here we demonstrate how a combin......Semiconductor device structures are becoming increasingly three-dimensional at the nanometer scale. A key issue that must be addressed to enable future device development is the three-dimensional mapping of dopant distributions, ideally under "working conditions". Here we demonstrate how...... a combination of electron holography and electron tomography can be used to determine quantitatively the three-dimensional electrostatic potential in an electrically biased semiconductor device with nanometer spatial resolution....

  7. A new three-dimensional conformal radiotherapy (3DCRT) technique for large breast and/or high body mass index patients: evaluation of a novel fields assessment aimed to reduce extra–target-tissue irradiation

    Science.gov (United States)

    Stimato, Gerardina; Ippolito, Edy; Silipigni, Sonia; Venanzio, Cristina Di; Gaudino, Diego; Fiore, Michele; Trodella, Lucio; D'Angelillo, Rolando Maria; Ramella, Sara

    2016-01-01

    Objective: To develop an alternative three-dimensional treatment plan with standardized fields class solution for whole-breast radiotherapy in patients with large/pendulous breast and/or high body mass index (BMI). Methods: Two treatment plans [tangential fields and standardized five-fields technique (S5F)] for a total dose of 50 Gy/25 fractions were generated for patients with large breasts [planning target volume (PTV) >1000 cm3 and/or BMI >25 kg m−2], supine positioned. S5F plans consist of two wedged tangential beams, anteroposterior: 20° for the right breast and 340° for the left breast, and posteroanterior: 181° for the right breast and 179° for the left breast. A field in field in medial–lateral beam and additional fields were added to reduce hot spot areas and extra–target-tissue irradiation and to improve dose distribution. The percentage of PTV receiving 95% of the prescribed dose (PTV V95%), percentage of PTV receiving 105% of the prescribed dose (PTV V105%), maximal dose to PTV (PTV Dmax), homogeneity index (HI) and conformity index were recorded. V10%, V20%, V105% and V107% of a “proper” normal tissue structure (body-PTV healthy tissue) were recorded. Statistical analyses were performed using SYSTAT v.12.0 (SPSS, Chicago, IL). Results: In 38 patients included, S5F improved HI (8.4 vs 10.1; p ≤ 0.001) and significantly reduced PTV Dmax and PTV V105%. The extra–target-tissue irradiation was significantly reduced using S5F for V105% (cm3) and V107% (cm3) with a very high difference in tissue irradiation (46.6 vs 3.0 cm3, p ≤ 0.001 for V105% and 12.2 vs 0.0 cm3, p ≤ 0.001 for V107% for tangential field and S5F plans, respectively). Only a slight increase in low-dose extra–target-tissue irradiation (V10%) was observed (2.2719 vs 1.8261 cm3, p = 0.002). Conclusion: The S5F technique in patients with large breast or high BMI increases HI and decreases hot spots in extra-target-tissues and can therefore be

  8. Intensity-modulated radiotherapy in patients with locally advanced rectal cancer reduces volume of bowel treated to high dose levels

    International Nuclear Information System (INIS)

    Urbano, M. Teresa Guerrero; Henrys, Anthony J.; Adams, Elisabeth J.; Norman, Andrew R.; Bedford, James L.; Harrington, Kevin J.; Nutting, Christopher M.; Dearnaley, David P.; Tait, Diana M.

    2006-01-01

    Purpose: To investigate the potential for intensity-modulated radiotherapy (IMRT) to spare the bowel in rectal tumors. Methods and Materials: The targets (pelvic nodal and rectal volumes), bowel, and bladder were outlined in 5 patients. All had conventional, three-dimensional conformal RT and forward-planned multisegment three-field IMRT plans compared with inverse-planned simultaneous integrated boost nine-field equally spaced IMRT plans. Equally spaced seven-field and five-field and five-field, customized, segmented IMRT plans were also evaluated. Results: Ninety-five percent of the prescribed dose covered at least 95% of both planning target volumes using all but the conventional plan (mean primary and pelvic planning target volume receiving 95% of the prescribed dose was 32.8 ± 13.7 Gy and 23.7 ± 4.87 Gy, respectively), reflecting a significant lack of coverage. The three-field forward planned IMRT plans reduced the volume of bowel irradiated to 45 Gy and 50 Gy by 26% ± 16% and 42% ± 27% compared with three-dimensional conformal RT. Additional reductions to 69 ± 51 cm 3 to 45 Gy and 20 ± 21 cm 3 to 50 Gy were obtained with the nine-field equally spaced IMRT plans-64% ± 11% and 64% ± 20% reductions compared with three-dimensional conformal RT. Reducing the number of beams and customizing the angles for the five-field equally spaced IMRT plan did not significantly reduce bowel sparing. Conclusion: The bowel volume irradiated to 45 Gy and 50 Gy was significantly reduced with IMRT, which could potentially lead to less bowel toxicity. Reducing the number of beams did not reduce bowel sparing and the five-field customized segmented IMRT plan is a reasonable technique to be tested in clinical trials

  9. Applications of three-dimensional image correlation in conformal radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Van Herk, M; Gilhuijs, K; Kwa, S; Lebesque, J; Muller, S; De Munck, J; Touw, A [Nederlands Kanker Inst. ` Antoni van Leeuwenhoekhuis` , Amsterdam (Netherlands); Kooy, H [Harvard Medical School, Boston, MA (United States)

    1995-12-01

    The development of techniques for the registration of CT, MRI and SPECT creates new possibilities for improved target volume definition and quantitative image analysis. The discussed technique is based on chamfer matching and is suitable for automatic 3-D matching of CT with CT, CT with MRI, CT with SPECT and MRI with SPECT. By integrating CT with MRI, the diagnostic qualities of MRI are combined with the geometric accuracy of the planning CT. Significant differences in the delineation of the target volume for brain, head and neck and prostate tumors were demonstrated when using integrated CT and MRI compared with using CT alone. In addition, integration of the planning CT with pre-operative scans improves knowledge of possible tumor extents. By first matching scans based on the bony anatomy and subsequently matching on an organ of study, relative motion of the organ is quantified accurately. In a study with 42 CT scans of 11 patients, magnitude and causes of prostate motion were analysed. The most important motion of the prostate is a forward-backward rotation around a point near the apex caused by rectal volume difference. Significant correlations were also found between motion of the legs and the prostate. By integrating functional images made before and after radiotherapy with the planning CT, the relation between local change of lung function and delivered dose has been quantified accurately. The technique of chamfer matching is a convenient and more accurate alternative for the use of external markers in a CT/SPECT lung damage study. Also, damage visible in diagnostic scans can be related to radiation dose, thereby improving follow-up diagnostics. It can be concluded that 3-D image integration plays an important role in assessing and improving the accuracy of radiotherapy and is therefore indispensable for conformal therapy. However, user-friendly implementation of these techniques remains to be done to facilitate clinical application on a large scale.

  10. Applications of three-dimensional image correlation in conformal radiotherapy

    International Nuclear Information System (INIS)

    Van Herk, M.; Gilhuijs, K.; Kwa, S.; Lebesque, J.; Muller, S.; De Munck, J.; Touw, A.; Kooy, H.

    1995-01-01

    The development of techniques for the registration of CT, MRI and SPECT creates new possibilities for improved target volume definition and quantitative image analysis. The discussed technique is based on chamfer matching and is suitable for automatic 3-D matching of CT with CT, CT with MRI, CT with SPECT and MRI with SPECT. By integrating CT with MRI, the diagnostic qualities of MRI are combined with the geometric accuracy of the planning CT. Significant differences in the delineation of the target volume for brain, head and neck and prostate tumors have been demonstrated when using integrated CT and MRI compared with using CT alone. In addition, integration of the planning CT with pre-operative scans improves knowledge of possible tumor extents. By first matching scans based on the bony anatomy and subsequently matching on an organ of study, relative motion of the organ is quantified accurately. In a study with 42 CT scans of 11 patients, magnitude and causes of prostate motion have been analysed. The most important motion of the prostate is a forward-backward rotation around a point near the apex caused by rectal volume difference. Significant correlations were also found between motion of the legs and the prostate. By integrating functional images made before and after radiotherapy with the planning CT, the relation between local change of lung function and delivered dose has been quantified accurately. The technique of chamfer matching is a convenient and more accurate alternative for the use of external markers in a CT/SPECT lung damage study. Also, damage visible in diagnostic scans can be related to radiation dose, thereby improving follow-up diagnostics. It can be concluded that 3-D image integration plays an important role in assessing and improving the accuracy of radiotherapy and is therefore indispensable for conformal therapy. However, user-friendly implementation of these techniques remains to be done to facilitate clinical application on a large

  11. The Effect of Dose-Volume Parameters and Interfraction Interval on Cosmetic Outcome and Toxicity After 3-Dimensional Conformal Accelerated Partial Breast Irradiation

    International Nuclear Information System (INIS)

    Leonard, Kara Lynne; Hepel, Jaroslaw T.; Hiatt, Jessica R.; Dipetrillo, Thomas A.; Price, Lori Lyn; Wazer, David E.

    2013-01-01

    Purpose: To evaluate dose-volume parameters and the interfraction interval (IFI) as they relate to cosmetic outcome and normal tissue effects of 3-dimensional conformal radiation therapy (3D-CRT) for accelerated partial breast irradiation (APBI). Methods and Materials: Eighty patients were treated by the use of 3D-CRT to deliver APBI at our institutions from 2003-2010 in strict accordance with the specified dose-volume constraints outlined in the National Surgical Adjuvant Breast and Bowel Project B39/Radiation Therapy Oncology Group 0413 (NSABP-B39/RTOG 0413) protocol. The prescribed dose was 38.5 Gy in 10 fractions delivered twice daily. Patients underwent follow-up with assessment for recurrence, late toxicity, and overall cosmetic outcome. Tests for association between toxicity endpoints and dosimetric parameters were performed with the chi-square test. Univariate logistic regression was used to evaluate the association of interfraction interval (IFI) with these outcomes. Results: At a median follow-up time of 32 months, grade 2-4 and grade 3-4 subcutaneous fibrosis occurred in 31% and 7.5% of patients, respectively. Subcutaneous fibrosis improved in 5 patients (6%) with extended follow-up. Fat necrosis developed in 11% of women, and cosmetic outcome was fair/poor in 19%. The relative volume of breast tissue receiving 5%, 20%, 50%, 80%, and 100% (V5-V100) of the prescribed dose was associated with risk of subcutaneous fibrosis, and the volume receiving 50%, 80%, and 100% (V50-V100) was associated with fair/poor cosmesis. The mean IFI was 6.9 hours, and the minimum IFI was 6.2 hours. The mean and minimum IFI values were not significantly associated with late toxicity. Conclusions: The incidence of moderate to severe late toxicity, particularly subcutaneous fibrosis and fat necrosis and resulting fair/poor cosmesis, remains high with continued follow-up. These toxicity endpoints are associated with several dose-volume parameters. Minimum and mean IFI values were

  12. High precision conformal radiotherapy employing conservative margins in childhood benign and low-grade brain tumours

    International Nuclear Information System (INIS)

    Jalali, Rakesh; Budrukkar, Ashwini; Sarin, Rajiv; Sharma, Dayananda S.

    2005-01-01

    Background and purpose: To report local control and follow up outcome data of high precision conformal radiotherapy in childhood brain tumours. Materials and methods: Between December 1999 and December 2002, 26 children (17 boys and 9 girls, median age 11.5 years) with incompletely excised or recurrent benign and low-grade brain tumours [13 craniopharyngiomas, 11 low-grade gliomas (LGG) and 2 others] were treated with three-dimensional (3D) conformal radiotherapy (CRT) (12 patients) and stereotactic conformal radiotherapy (SCRT) (14 patients). Gross tumour volume (GTV) included neuro-imaging based visible tumour and/or resected tumour bed. Clinical target volume (CTV) consisted of GTV + 5 mm margin and planning target volume (PTV) consisted of additional 5 mm margin for CRT and 2 mm for SCRT. Treatment was delivered with 3-9 conformal fixed fields to a median dose of 54 Gy/30 fractions. Results: The actuarial 2 and 3 year disease free and overall survival was 96 and 100%, respectively (median follow up: 25 months, range 12-47 months). Radiological follow up available in 25 patients revealed complete response in 1, partial regression in 10, stable disease in 13 and progression in 1 patient (within the CTV). One patient with craniopharyngioma on a routine imaging revealed a mild asymptomatic cyst enlargement, which resolved with conservative management. A patient with chiasmatic glioma developed cystic degeneration and hydrocephalus 9 months after SCRT requiring cyst drainage and placement of a ventriculoperitoneal shunt. Conclusion: High-precision conformal techniques delivering irradiation to a computer generated target volume employing 7-10 mm 3D margins beyond the visible tumour and/or resected tumour bed appear to be safe in children with incompletely resected or recurrent benign and low-grade brain tumours, based on these data

  13. Conformal intensity-modulated radiotherapy (IMRT) delivered by robotic linac-conformality versus efficiency of dose delivery

    International Nuclear Information System (INIS)

    Webb, Steve

    2000-01-01

    Intensity-modulated radiotherapy (IMRT) may be delivered with a high-energy-photon linac mounted on a robotic gantry and executing a complex trajectory. In a previous paper an inverse-planning technique was developed for such an application. Here the work is extended to demonstrate the dependence of conformality on the size of the elemental pencil beam, on the complexity of the trajectory and on the sampling of azimuth and elevation of the collimated source. The improved conformality of complex trajectories is demonstrated and benchmarked relative to simpler trajectories, more representative of existing non-robotic IMRT techniques. Specifically, by choosing a very fine pencil beam, exquisitely conformal dose distributions have been obtained. Important sampling considerations have been determined. Expressions have been derived for the dosimetry and monitor-unit efficiency of robotic IMRT. Equivalent trajectories were computed for executing the complex robotic trajectories instead by using a conventional linac. The work benchmarks an ideal in IMRT against which more practical and more common techniques may be measured. (author)

  14. Fractionated, three-dimensional, planning-assisted proton-radiation therapy for orbital rhabdomyosarcoma: a novel technique

    International Nuclear Information System (INIS)

    Hug, Eugen B.; Adams, Judy; Fitzek, Markus; Vries, Alexander de; Munzenrider, John E.

    2000-01-01

    Purpose: Most children with orbital rhabdomyosarcoma will survive their disease. However, conventional photon-radiation treatment, as part of multimodality therapy, results in varying degrees of long-term functional and cosmetic side effects. This report introduces external beam proton radiation therapy (PRT) as a conformal, three-dimensional planned radiation technique for this disease, analyzes normal tissue dosimetry, and describes the technique's application in the first 2 patients. Material and Methods: Between January 1995 and February 1996, 2 patients underwent PRT following biopsy and chemotherapy for orbital rhabdomyosarcoma. Fifty and 55 Cobalt Gray Equivalent (CGE) were delivered to the gross tumor volume and 40 CGE to clinical target volumes in both patients. A relative biologic effectiveness (RBE) of 1.1 was utilized to correlate proton dose calculations with CGE. To achieve dose conformity, a ''patch technique'' was utilized, where target regions were divided into segments, each treated by a separate proton field. Dose-volume histograms were obtained for target and nontarget regions, including lens, bony orbit, pituitary gland, optic chiasm, optic nerves, lacrimal gland, and ipsilateral frontal and temporal lobes. Results: At 3.4 and 2.5 years after PRT, both patients are clinically and radiographically free of disease. Visual acuity remains excellent, without signs of cataract formation; pituitary function is normal; cosmetically, only mild enophthalmos is noticeable. Doses to 90%, 50%, and 5% of lens volume were kept at less than 1%, less than 2%, and less than 8%, respectively. Fifty percent of lacrimal gland volume received less than 36% of the prescribed dose and 50% of the volume of the optic chiasm, pituitary gland, and hypothalamus were restricted to less than 2%. Proton conformity to orbital contents resulted in between 9% and 36% of the prescribed dose reaching the ipsilateral temporal and frontal lobes immediately adjacent to bony orbit (5

  15. Three-dimensional conformal radiotherapy with concurrent chemotherapy for postoperative recurrence of esophageal squamous cell carcinoma: clinical efficacy and failure pattern

    International Nuclear Information System (INIS)

    Bao, Yong; Rong, TieHua; Li, Qun; Liu, Hui; Liu, ShiLiang; Zhou, QiChao; Cai, PeiQiang; Anfossi, Simone; Li, QiaoQiao; Hu, YongHong; Liu, MengZhong; Fu, JianHua

    2013-01-01

    To assess the therapeutic outcome and failure pattern of three-dimensional conformal radiotherapy (3D-CRT)-based concurrent chemoradiotherapy (CCRT) for recurrence of esophageal squamous cell carcinoma (SCC) after radical surgery. Treatment outcome and failure pattern were retrospectively evaluated in 83 patients with localized cervical and thoracic recurrences after radical surgery for thoracic esophageal SCC. All patients were treated with 3DCRT-based CCRT (median radiation dose 60 Gy), in which 39 received concurrent cisplatin plus 5-fluorouracil (PF), and 44 received concurrent docetaxel plus cisplatin (TP). Treatment response was evaluated at 1–3 months after CCRT. With a median follow-up of 34 months (range, 2–116 months), the 3-year overall survival (OS) of all the patients was 51.8% and the median OS time was 43.0 months. The overall tumor response rate was 75.9% (63/83), with a complete remission (CR) rate of 44.6% (37/83). In univariate analysis, tumor response after CCRT (p = 0.000), recurrence site (p = 0.028) and concurrent chemotherapy (p = 0.090) showed a trend favoring better OS. Multivariate analysis revealed that tumor response after CCRT (p = 0.000) and concurrent chemotherapy (p = 0.010) were independent predictors of OS. Forty-seven patients had progressive diseases after CCRT, 27 had local failure (27/47, 57.4%), 18 had distant metastasis (18/47, 38.3%) and 2 had both local and distant failures (2/47, 4.3%). 3DCRT-based CCRT is effective in postoperatively recurrent esophageal SCC. Patients that obtained complete remission after CCRT appeared to achieve long-term OS and might benefit from concurrent TP regimen. Local and distant failures remained high and prospective studies are needed to validate these factors

  16. Analysis of dose volume histogram parameters to estimate late bladder and rectum complications after high-dose (70-78 Gy) conformal radiotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Boersma, L.J.; Brink, M. van den; Bruce, A.; Gras, L.; Velde, A. te; Lebesque, J.V.

    1997-01-01

    Purpose: To investigate whether Dose Volume Histogram (DVH) parameters can be used to identify risk groups for developing late gastrointestinal (GI) and genitourinary (GU) complications after conformal radiotherapy for prostate cancer, and to examine the effect of using different morbidity scoring systems on the results of these analyses. Materials and Methods: DVH parameters were analyzed for 130 patients with localized prostate cancer, treated with conformal radiotherapy in a dose-escalating protocol (70-78 Gy, 2 Gy per fraction). The incidence of late (> 6 months) GI and GU complications was scored based on questionnaires and classified using the RTOG/EORTC and the SOMA/LENT scoring system. Moreover, patients were classified as being a rectal bleeder or no rectal bleeder and a distinction was made between non-severe and severe (requiring one or more laser treatments) rectal bleeding. The median follow-up time was 22 months. It was investigated whether the relative and absolute rectal wall volumes, irradiated to various dose levels (≥ 60 Gy, ≥ 65 Gy, ≥ 70 Gy and ≥ 75 Gy) were correlated with the observed actuarial incidences of GI complications. First, the analysis was performed using volume as a continuous variable. Subsequently, for each dose level in the DVH the rectal wall volumes were dichotomized using different volumes as cut-off levels. Twenty cut-off levels were tested on their ability to discriminate between high and low risk for developing GI complications (Fig.). The relationship between bladder wall volumes irradiated to various dose levels and observed actuarial GU complications was investigated using the absolute bladder wall volumes, measured as a continuous variable. For both GI and GU complications, the role of the prescribed radiation dose and the maximum radiation dose in the rectal and bladder wall was analyzed as well. Results: None of the DVH parameters of the rectal wall was significantly correlated with the actuarial incidences of

  17. MO-B-BRB-00: Three Dimensional Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2016-06-15

    Full three-dimensional (3D) dosimetry using volumetric chemical dosimeters probed by 3D imaging systems has long been a promising technique for the radiation therapy clinic, since it provides a unique methodology for dose measurements in the volume irradiated using complex conformal delivery techniques such as IMRT and VMAT. To date true 3D dosimetry is still not widely practiced in the community; it has been confined to centres of specialized expertise especially for quality assurance or commissioning roles where other dosimetry techniques are difficult to implement. The potential for improved clinical applicability has been advanced considerably in the last decade by the development of improved 3D dosimeters (e.g., radiochromic plastics, radiochromic gel dosimeters and normoxic polymer gel systems) and by improved readout protocols using optical computed tomography or magnetic resonance imaging. In this session, established users of some current 3D chemical dosimeters will briefly review the current status of 3D dosimetry, describe several dosimeters and their appropriate imaging for dose readout, present workflow procedures required for good dosimetry, and analyze some limitations for applications in select settings. We will review the application of 3D dosimetry to various clinical situations describing how 3D approaches can complement other dose delivery validation approaches already available in the clinic. The applications presented will be selected to inform attendees of the unique features provided by full 3D techniques. Learning Objectives: L. John Schreiner: Background and Motivation Understand recent developments enabling clinically practical 3D dosimetry, Appreciate 3D dosimetry workflow and dosimetry procedures, and Observe select examples from the clinic. Sofie Ceberg: Application to dynamic radiotherapy Observe full dosimetry under dynamic radiotherapy during respiratory motion, and Understand how the measurement of high resolution dose data in an

  18. High-dose intensity modulated radiation therapy for prostate cancer: early toxicity and biochemical outcome in 772 patients

    International Nuclear Information System (INIS)

    Zelefsky, Michael J.; Fuks, Zvi; Hunt, Margie; Yamada, Yoshiya; Marion, Christine; Ling, C. Clifton; Amols, Howard; Venkatraman, E.S.; Leibel, Steven A.

    2002-01-01

    significantly reduced compared with what has been observed with conventional three-dimensional conformal radiotherapy techniques. Short-term PSA control rates seem to be at least comparable to those achieved with three-dimensional conformal radiotherapy at similar dose levels. Based on this favorable risk:benefit ratio, IMRT has become the standard mode of conformal treatment delivery for localized prostate cancer at our institution

  19. Evidence for increased failure in patients with perineural invasion treated with three-dimensional conformal radiation therapy

    International Nuclear Information System (INIS)

    Bonin, S.R.; Hanlon, A.L.; Lee, W.R.; Movsas, B.; Al-Saleem, T.I.; Hanks, G.E.

    1996-01-01

    Purpose/Objective: The detection of perineural invasion (PNI) on diagnostic transrectal biopsy of the prostate is associated with a 93% frequency of extracapsular disease extension in patients treated by prostatectomy for adenocarcinoma of the prostate. This finding is associated with a worse outcome compared with those who have organ confined disease. This study examines the association of PNI and treatment failure in a consecutive series of patients treated by three-dimensional conformal radiation therapy (3DCRT) alone. Materials and Methods: We report actuarial biochemical NED (bNED) survival rates for 484 consecutive patients with clinically localized prostate cancer diagnosed by transrectal needle biopsy who have completed 3DCRT alone between May 1989 and December 1994. The median follow-up time is 28 months (range 2-75 months), and median dose to the center of the prostate was 7368 cGy (range 6316-8074 cGy). Patients were subdivided into two groups according to pretreatment PSA levels (<20 ngm/ml vs ≥20 ngm/ml). Pathology records were reviewed for the presence or absence of PNI. bNED failure is defined as PSA ≥ 1.5 ngm/ml and rising on two consecutive values. bNED survival rates were calculated using Kaplan-Meier methodology and comparisons of survival curves were accomplished using the log-rank test. Results: There was no difference in the bNED survival rates for all patients, or for the subgroup of patients with pretreatment PSA values ≥20. However, figure 1 shows the bNED survival rates for patients with pretreatment PSA below 20 ngm/ml based on PNI. This subgroup demonstrates a highly significant decrease in bNED survival (65% vs 88% at 3 yrs, 39% vs 65% at 5 yrs; p=.0009 for overall curve comparison) if PNI is present. For patients with pretreatment PSA below 20 ngm/ml, multivariate analysis of prognostic variables demonstrated a significant association between bNED survival and PNI (p=.04), Gleason score (p=.02) and pretreatment PSA (p=.003

  20. A decision model to estimate the cost-effectiveness of intensity modulated radiation therapy (IMRT) compared to three dimensional conformal radiation therapy (3DCRT) in patients receiving radiotherapy to the prostate bed

    International Nuclear Information System (INIS)

    Carter, Hannah E.; Martin, Andrew; Schofield, Deborah; Duchesne, Gillian; Haworth, Annette; Hornby, Colin; Sidhom, Mark; Jackson, Michael

    2014-01-01

    Background: Intensity modulated radiation therapy (IMRT) is a radiation therapy technology that facilitates the delivery of an improved dose distribution with less dose to surrounding critical structures. This study estimates the longer term effectiveness and cost-effectiveness of IMRT in patients post radical prostatectomy. Methods: A Markov decision model was developed to calculate the incremental quality adjusted life years (QALYs) and costs of IMRT compared with three dimensional conformal radiation therapy (3DCRT). Costs were estimated from the perspective of the Australian health care system. Results: IMRT was both more effective and less costly than 3DCRT over 20 years, with an additional 20 QALYs gained and over $1.1 million saved per 1000 patients treated. This result was robust to plausible levels of uncertainty. Conclusions: IMRT was estimated to have a modest long term advantage over 3DCRT in terms of both improved effectiveness and reduced cost. This result was reliant on clinical judgement and interpretation of the existing literature, but provides quantitative guidance on the cost effectiveness of IMRT whilst long term trial evidence is awaited

  1. Intensity-modulated radiation therapy versus three-dimensional conformal radiation therapy with concurrent nedaplatin-based chemotherapy after radical hysterectomy for uterine cervical cancer: comparison of outcomes, complications, and dose-volume histogram parameters

    International Nuclear Information System (INIS)

    Isohashi, Fumiaki; Mabuchi, Seiji; Yoshioka, Yasuo; Seo, Yuji; Suzuki, Osamu; Tamari, Keisuke; Yamashita, Michiko; Unno, Hikari; Kinose, Yasuto; Kozasa, Katsumi; Sumida, Iori; Otani, Yuki; Kimura, Tadashi; Ogawa, Kazuhiko

    2015-01-01

    The purpose of this study is to report our clinical outcomes using intensity-modulated radiation therapy (IMRT) for adjuvant treatment of cervical cancer, compared with three-dimensional conformal radiation therapy (3DCRT), in terms of tumor control, complications and dose-volume histogram (DVH) parameters. Between March 2008 and February 2014, 62 patients were treated with concurrent nedaplatin-based chemotherapy and whole-pelvic external beam radiation therapy (RT). Of these patients, 32 (52 %) received 3DCRT and 30 (48 %) received IMRT. The median follow-up periods were 40 months (range 2–74 months). The 3-year overall survival rate (OS), locoregional control rate (LRC) and progression-free survival rate (PFS) were 92, 95 and 92 % in the IMRT group, and 85, 82 and 70 % in the 3DCRT group, respectively. A comparison of OS, LRC and PFS showed no significant differences between IMRT and 3DCRT. The 3-year cumulative incidences of grade 2 or higher chronic gastrointestinal (GI) complications were significantly lower with IMRT compared to 3DCRT (3 % vs. 45 %, p < .02) and in patients with V40 of the small bowel loops of ≤340 mL compared to those with >340 mL (3 % vs. 45 %, p < .001). Patients treated with IMRT had a higher incidence of grade 3 acute hematologic complications (p < .05). V40 and V45 of the small bowel loops or bowel bag were predictive for development of both acute and chronic GI complications. Our results suggest that IMRT for adjuvant treatment of cervical cancer is useful for decreasing GI complications without worsening outcomes

  2. Three-dimensional photon dose distributions with and without lung corrections for tangential breast intact treatments

    International Nuclear Information System (INIS)

    Chin, L.M.; Cheng, C.W.; Siddon, R.L.; Rice, R.K.; Mijnheer, B.J.; Harris, J.R.

    1989-01-01

    The influence of lung volume and photon energy on the 3-dimensional dose distribution for patients treated by intact breast irradiation is not well established. To investigate this issue, we studied the 3-dimensional dose distributions calculated for an 'average' breast phantom for 60Co, 4 MV, 6 MV, and 8 MV photon beams. For the homogeneous breast, areas of high dose ('hot spots') lie along the periphery of the breast near the posterior plane and near the apex of the breast. The highest dose occurs at the inferior margin of the breast tissue, and this may exceed 125% of the target dose for lower photon energies. The magnitude of these 'hot spots' decreases for higher energy photons. When lung correction is included in the dose calculation, the doses to areas at the left and right margin of the lung volume increase. The magnitude of the increase depends on energy and the patient anatomy. For the 'average' breast phantom (lung density 0.31 g/cm3), the correction factors are between 1.03 to 1.06 depending on the energy used. Higher energy is associated with lower correction factors. Both the ratio-of-TMR and the Batho lung correction methods can predict these corrections within a few percent. The range of depths of the 100% isodose from the skin surface, measured along the perpendicular to the tangent of the skin surface, were also energy dependent. The range was 0.1-0.4 cm for 60Co and 0.5-1.4 cm for 8 MV. We conclude that the use of higher energy photons in the range used here provides lower value of the 'hot spots' compared to lower energy photons, but this needs to be balanced against a possible disadvantage in decreased dose delivered to the skin and superficial portion of the breast

  3. Assignment strategies in homonuclear three-dimensional 1H NMR spectra of proteins

    International Nuclear Information System (INIS)

    Vuister, G.W.; Boelens, R.; Padilla, A.; Kleywegt, G.J.; Kaptein, R.

    1990-01-01

    The increase in dimensionality of three-dimensional (3D) NMR greatly enhances the spectral resolution in comparison to 2D NMR. It alleviates the problem of resonance overlap and may extend the range of molecules amenable to structure determination by high-resolution NMR spectroscopy. Here, the authors present strategies for the assignment of protein resonances from homonuclear nonselective 3D NOE-HOHAHA spectra. A notation for connectivities between protons, corresponding to cross peaks in 3D spectra, is introduced. They show how spin systems can be identified by tracing cross-peak patterns in cross sections perpendicular to the three frequency axes. The observable 3D sequential connectivities in proteins are tabulated, and estimates for the relative intensities of the corresponding cross peaks are given for α-helical and β-sheet conformations. Intensities of the cross peaks in the 3D spectrum of pike III paravalbumin follow the predictions. The sequential-assignment procedure is illustrated for loop regions, extended and α-helical conformations for the residues Ala 54-Leu 63 of paravalbumin. NOEs that were not previously identified in 2D spectra of paravalbumin due to overlap are found

  4. Evaluating four-loop conformal Feynman integrals by D-dimensional differential equations

    Science.gov (United States)

    Eden, Burkhard; Smirnov, Vladimir A.

    2016-10-01

    We evaluate a four-loop conformal integral, i.e. an integral over four four-dimensional coordinates, by turning to its dimensionally regularized version and applying differential equations for the set of the corresponding 213 master integrals. To solve these linear differential equations we follow the strategy suggested by Henn and switch to a uniformly transcendental basis of master integrals. We find a solution to these equations up to weight eight in terms of multiple polylogarithms. Further, we present an analytical result for the given four-loop conformal integral considered in four-dimensional space-time in terms of single-valued harmonic polylogarithms. As a by-product, we obtain analytical results for all the other 212 master integrals within dimensional regularization, i.e. considered in D dimensions.

  5. Evaluating four-loop conformal Feynman integrals by D-dimensional differential equations

    Energy Technology Data Exchange (ETDEWEB)

    Eden, Burkhard [Institut für Mathematik und Physik, Humboldt-Universität zu Berlin,Zum großen Windkanal 6, 12489 Berlin (Germany); Smirnov, Vladimir A. [Skobeltsyn Institute of Nuclear Physics, Moscow State University,119992 Moscow (Russian Federation)

    2016-10-21

    We evaluate a four-loop conformal integral, i.e. an integral over four four-dimensional coordinates, by turning to its dimensionally regularized version and applying differential equations for the set of the corresponding 213 master integrals. To solve these linear differential equations we follow the strategy suggested by Henn and switch to a uniformly transcendental basis of master integrals. We find a solution to these equations up to weight eight in terms of multiple polylogarithms. Further, we present an analytical result for the given four-loop conformal integral considered in four-dimensional space-time in terms of single-valued harmonic polylogarithms. As a by-product, we obtain analytical results for all the other 212 master integrals within dimensional regularization, i.e. considered in D dimensions.

  6. Three dimensional measurement of dose distributions produced by a robot-mounted linac using magnetic resonance imaging of bang polymer gel dosimeters

    International Nuclear Information System (INIS)

    Wong, S.P.; Garwood, D.P.; Clarke, G.D.; McColl, R.W.; Maryanski, M.J.; Gore, J.C.

    1996-01-01

    Purpose/Objective: A novel image-guided robotic radiosurgical system, capable of irradiating 102 non-coplanar nodes in 3 π geometry, produces complex dose distributions which are difficult or impractical to measure with conventional dosimetry instrumentation. The recently developed BANG polymer gel dosimetry system provides accurate, high resolution and three dimensional dose distributions data and is ideally suited for the task described above. In this study, the polymer gels were used for imaging the dose distributions produced by this extremely flexible radiosurgical system. Materials and Methods: The dosimeter materials consist of 2-liter BANG polymer gels in spherical, clear glass flasks, closed with ground glass stoppers, with glass rods extending to the center of the gel that serve as a target for the frameless robotic radiosurgery. A compact 6 MV x-band linac (285 lbs) is mounted and maneuvered by a 6 degree-of-freedom robotic arm. The gels were irradiated using a 25 mm circular insert. A total of 10 Gy was delivered at isocenter at a dose rate of 300 cGy/min using all of the available 102 nodes. The gels were then imaged by MRI(GE Signa) at 1.5 T, using a series of Hahn spin echoes of TR = 3s, TE = 20,100,200,400 ms. Transverse relaxation rate (R 2 ) maps were constructed from those multiple images, using the non-linear least-squares Lavenberg-Marquardt algorithm and a data analysis and display program 'DoseMap' which was written using the scientific computational program MATLAB. R 2 maps were converted to dose maps using an R 2 -to-dose calibration curve. Dose maps and isodose curves were then compared with corresponding data from the treatment planning computer software. Results: The dose dependence of the NMR transverse relaxation rate, R 2 , is reproducible (less than 2 % variation) and is linear up to about 10 Gy, with a slope of 0.25 s -1 Gy -1 at 1.5 Tesla. Isodose curves in three orthogonal (axial, sagittal and coronal) planes show excellent

  7. Spine stereotactic body radiation therapy plans: Achieving dose coverage, conformity, and dose falloff

    International Nuclear Information System (INIS)

    Hong, Linda X.; Shankar, Viswanathan; Shen, Jin; Kuo, Hsiang-Chi; Mynampati, Dinesh; Yaparpalvi, Ravindra; Goddard, Lee; Basavatia, Amar; Fox, Jana; Garg, Madhur; Kalnicki, Shalom; Tomé, Wolfgang A.

    2015-01-01

    We report our experience of establishing planning objectives to achieve dose coverage, conformity, and dose falloff for spine stereotactic body radiation therapy (SBRT) plans. Patients with spine lesions were treated using SBRT in our institution since September 2009. Since September 2011, we established the following planning objectives for our SBRT spine plans in addition to the cord dose constraints: (1) dose coverage—prescription dose (PD) to cover at least 95% planning target volume (PTV) and 90% PD to cover at least 99% PTV; (2) conformity index (CI)—ratio of prescription isodose volume (PIV) to the PTV < 1.2; (3) dose falloff—ratio of 50% PIV to the PTV (R 50% ); (4) and maximum dose in percentage of PD at 2 cm from PTV in any direction (D 2cm ) to follow Radiation Therapy Oncology Group (RTOG) 0915. We have retrospectively reviewed 66 separate spine lesions treated between September 2009 and December 2012 (31 treated before September 2011 [group 1] and 35 treated after [group 2]). The χ 2 test was used to examine the difference in parameters between groups. The PTV V 100% PD ≥ 95% objective was met in 29.0% of group 1 vs 91.4% of group 2 (p < 0.01) plans. The PTV V 90% PD ≥ 99% objective was met in 38.7% of group 1 vs 88.6% of group 2 (p < 0.01) plans. Overall, 4 plans in group 1 had CI > 1.2 vs none in group 2 (p = 0.04). For D 2cm , 48.3% plans yielded a minor violation of the objectives and 16.1% a major violation for group 1, whereas 17.1% exhibited a minor violation and 2.9% a major violation for group 2 (p < 0.01). Spine SBRT plans can be improved on dose coverage, conformity, and dose falloff employing a combination of RTOG spine and lung SBRT protocol planning objectives

  8. Spine stereotactic body radiation therapy plans: Achieving dose coverage, conformity, and dose falloff

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Linda X., E-mail: lhong0812@gmail.com [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States); Shankar, Viswanathan [Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY (United States); Shen, Jin [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Kuo, Hsiang-Chi [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States); Mynampati, Dinesh [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Yaparpalvi, Ravindra [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States); Goddard, Lee [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Basavatia, Amar; Fox, Jana; Garg, Madhur; Kalnicki, Shalom; Tomé, Wolfgang A. [Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY (United States); Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, NY (United States)

    2015-10-01

    We report our experience of establishing planning objectives to achieve dose coverage, conformity, and dose falloff for spine stereotactic body radiation therapy (SBRT) plans. Patients with spine lesions were treated using SBRT in our institution since September 2009. Since September 2011, we established the following planning objectives for our SBRT spine plans in addition to the cord dose constraints: (1) dose coverage—prescription dose (PD) to cover at least 95% planning target volume (PTV) and 90% PD to cover at least 99% PTV; (2) conformity index (CI)—ratio of prescription isodose volume (PIV) to the PTV < 1.2; (3) dose falloff—ratio of 50% PIV to the PTV (R{sub 50%}); (4) and maximum dose in percentage of PD at 2 cm from PTV in any direction (D{sub 2cm}) to follow Radiation Therapy Oncology Group (RTOG) 0915. We have retrospectively reviewed 66 separate spine lesions treated between September 2009 and December 2012 (31 treated before September 2011 [group 1] and 35 treated after [group 2]). The χ{sup 2} test was used to examine the difference in parameters between groups. The PTV V{sub 100%} {sub PD} ≥ 95% objective was met in 29.0% of group 1 vs 91.4% of group 2 (p < 0.01) plans. The PTV V{sub 90%} {sub PD} ≥ 99% objective was met in 38.7% of group 1 vs 88.6% of group 2 (p < 0.01) plans. Overall, 4 plans in group 1 had CI > 1.2 vs none in group 2 (p = 0.04). For D{sub 2cm}, 48.3% plans yielded a minor violation of the objectives and 16.1% a major violation for group 1, whereas 17.1% exhibited a minor violation and 2.9% a major violation for group 2 (p < 0.01). Spine SBRT plans can be improved on dose coverage, conformity, and dose falloff employing a combination of RTOG spine and lung SBRT protocol planning objectives.

  9. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    International Nuclear Information System (INIS)

    Zhang, Yuxiao; Zhang, Jianming; Liu, Yang; Huang, Hui; Kang, Zhenhui

    2012-01-01

    Highlights: ► Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. ► MPCS was covalently modified by cysteine (MPCS–CO–Cys). ► MPCS–CO–Cys was first time used in electrochemical detection of heavy metal ions. ► Heavy metal ions such as Pb 2+ and Cd 2+ can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  10. Intensity-Modulated Radiotherapy versus 3-Dimensional Conformal Radiotherapy Strategies for Locally Advanced Non-Small-Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Uğur Selek

    2014-12-01

    Full Text Available Chemoradiotherapy is the current standard of care in patients with advanced inoperable stage IIIA or IIIB non-small cell lung cancer (NSCLC. Three-dimensional radiotherapy (3DCRT has been a trusted method for a long time and has well-known drawbacks, most of which could be improved by Intensity Modulated Radiotherapy (IMRT. IMRT is not currently the standard treatment of locally advanced NSCLC, but almost all patients could benefit to a degree in organ at risk sparing, dose coverage conformality, or dose escalation. The most critical step for a radiation oncology department is to strictly evaluate its own technical and physical capabilities to determine the ability of IMRT to deliver an optimal treatment plan. This includes calculating the internal tumor motion (ideally 4DCT or equivalent techniques, treatment planning software with an up-to-date heterogeneity correction algorithm, and daily image guidance. It is crucial to optimise and individualise the therapeutic ratio for each patient during the decision of 3DCRT versus IMRT. The current literature rationalises the increasing use of IMRT, including 4D imaging plus PET/CT, and encourages the applicable knowledge-based and individualised dose escalation using advanced daily image-guided radiotherapy.

  11. Comparison of static conformal field with multiple noncoplanar arc techniques for stereotactic radiosurgery or stereotactic radiotherapy

    International Nuclear Information System (INIS)

    Hamilton, Russell J.; Kuchnir, Franca T.; Sweeney, Patrick; Rubin, Steven J.; Dujovny, Manuel; Pelizzari, Charles A.; Chen, George T. Y.

    1995-01-01

    Purpose: Compare the use of static conformal fields with the use of multiple noncoplanar arcs for stereotactic radiosurgery or stereotactic radiotherapy treatment of intracranial lesions. Evaluate the efficacy of these treatment techniques to deliver dose distributions comparable to those considered acceptable in current radiotherapy practice. Methods and Materials: A previously treated radiosurgery case of a patient presenting with an irregularly shaped intracranial lesion was selected. Using a three-dimensional (3D) treatment-planning system, treatment plans using a single isocenter multiple noncoplanar arc technique and multiple noncoplanar conformal static fields were generated. Isodose distributions and dose volume histograms (DVHs) were computed for each treatment plan. We required that the 80% (of maximum dose) isodose surface enclose the target volume for all treatment plans. The prescription isodose was set equal to the minimum target isodose. The DVHs were analyzed to evaluate and compare the different treatment plans. Results: The dose distribution in the target volume becomes more uniform as the number of conformal fields increases. The volume of normal tissue receiving low doses (> 10% of prescription isodose) increases as the number of static fields increases. The single isocenter multiple arc plan treats the greatest volume of normal tissue to low doses, approximately 1.6 times more volume than that treated by four static fields. The volume of normal tissue receiving high (> 90% of prescription isodose) and intermediate (> 50% of prescription isodose) doses decreases by 29 and 22%, respectively, as the number of static fields is increased from four to eight. Increasing the number of static fields to 12 only further reduces the high and intermediate dose volumes by 10 and 6%, respectively. The volume receiving the prescription dose is more than 3.5 times larger than the target volume for all treatment plans. Conclusions: Use of a multiple noncoplanar

  12. Selection and determination of beam weights based on genetic algorithms for conformal radiotherapy treatment planning

    International Nuclear Information System (INIS)

    Xingen Wu; Zunliang Wang

    2000-01-01

    A genetic algorithm has been used to optimize the selection of beam weights for external beam three-dimensional conformal radiotherapy treatment planning. A fitness function is defined, which includes a difference function to achieve a least-square fit to doses at preselected points in a planning target volume, and a penalty item to constrain the maximum allowable doses delivered to critical organs. Adjustment between the dose uniformity within the target volume and the dose constraint to the critical structures can be achieved by varying the beam weight variables in the fitness function. A floating-point encoding schema and several operators, like uniform crossover, arithmetical crossover, geometrical crossover, Gaussian mutation and uniform mutation, have been used to evolve the population. Three different cases were used to verify the correctness of the algorithm and quality assessment based on dose-volume histograms and three-dimensional dose distributions were given. The results indicate that the genetic algorithm presented here has considerable potential. (author)

  13. Scanning three-dimensional x-ray diffraction microscopy using a high-energy microbeam

    International Nuclear Information System (INIS)

    Hayashi, Y.; Hirose, Y.; Seno, Y.

    2016-01-01

    A scanning three-dimensional X-ray diffraction (3DXRD) microscope apparatus with a high-energy microbeam was installed at the BL33XU Toyota beamline at SPring-8. The size of the 50 keV beam focused using Kirkpatrick-Baez mirrors was 1.3 μm wide and 1.6 μm high in full width at half maximum. The scanning 3DXRD method was tested for a cold-rolled carbon steel sheet sample. A three-dimensional orientation map with 37 "3 voxels was obtained.

  14. Scanning three-dimensional x-ray diffraction microscopy using a high-energy microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Y., E-mail: y-hayashi@mosk.tytlabs.co.jp; Hirose, Y.; Seno, Y. [Toyota Central R& D Toyota Central R& D Labs., Inc., 41-1 Nagakute Aichi 480-1192 Japan (Japan)

    2016-07-27

    A scanning three-dimensional X-ray diffraction (3DXRD) microscope apparatus with a high-energy microbeam was installed at the BL33XU Toyota beamline at SPring-8. The size of the 50 keV beam focused using Kirkpatrick-Baez mirrors was 1.3 μm wide and 1.6 μm high in full width at half maximum. The scanning 3DXRD method was tested for a cold-rolled carbon steel sheet sample. A three-dimensional orientation map with 37 {sup 3} voxels was obtained.

  15. On the Zeeman Effect in highly excited atoms: 2. Three-dimensional case

    International Nuclear Information System (INIS)

    Baseia, B.; Medeiros e Silva Filho, J.

    1984-01-01

    A previous result, found in two-dimensional hydrogen-atoms, is extended to the three-dimensional case. A mapping of a four-dimensional space R 4 onto R 3 , that establishes an equivalence between Coulomb and harmonic potentials, is used to show that the exact solution of the Zeeman effect in highly excited atoms, cannot be reached. (Author) [pt

  16. Advantages of three-dimensional treatment planning in radiation therapy

    International Nuclear Information System (INIS)

    Attalla, E.M.; ELSAyed, A.A.; ElGantiry, M.; ElTahher, Z.

    2003-01-01

    This study was designed to demonstrate the feasibility of three-dimensional (3-D) treatment planning in-patients maxilla, breast, bladder, and lung tumors to explore its potential therapeutic advantage over the traditional dimensional (2-D) approach in these diseases. Conventional two-dimensional (2-D) treatment planning was compared to three-dimensional (3-D) treatment planning. In five selected disease sites, plans calculated with both types of treatment planning were compared. The (3-D) treatment planning system used in this work TMS version 5.1 B from helax AB is based on a monte Carlo-based pencil beam model. The other treatment planning system (2-D 0, introduced in this study was the multi data treatment planning system version 2.35. For the volumes of interest; quality of dose distribution concerning homogeneity in the target volume and the isodose distribution in organs at risk, was discussed. Qualitative and quantitative comparisons between the two planning systems were made using dose volume histograms (DVH's) . For comparisons of dose distributions in real-patient cases, differences ranged from 0.8% to 6.4% for 6 MV, while in case of 18 MV photon, it ranged from 1,8% to 6.5% and was within -+3 standard deviations for the dose between the two planning systems.Dose volume histogram (DVH) shows volume reduction of the radiation-related organs at risk 3-D planning

  17. Comparação entre os volumes pulmonares irradiados com técnica bidimensional e tridimensional conformada na radioterapia de pacientes com tumores de pulmão localmente avançados Comparison between irradiated lung volumes with two-dimensional and three-dimensional conformal radiotherapy techniques for locally advanced lung cancer

    Directory of Open Access Journals (Sweden)

    Heloisa de Andrade Carvalho

    2009-10-01

    Full Text Available OBJETIVO: Comparar e quantificar os volumes pulmonares irradiados utilizando planejamentos bidimensional (2D e tridimensional (3D conformado na radioterapia de tumores de pulmão. MATERIAIS E MÉTODOS: Em 27 pacientes portadores de câncer de pulmão foi feito planejamento 3D e outro correspondente em 2D. As doses prescritas variaram de 45 a 66 Gy. Foram avaliadas as doses no volume alvo planejado (PTV, volume tumoral macroscópico (GTV e pulmões (volume de pulmão que recebe 20 Gy ou 30 Gy - V20 e V30, respectivamente, e dose média. Os órgãos de risco adjacentes (medula espinhal, esôfago e coração receberam doses abaixo dos limites de tolerância. RESULTADOS: O GTV variou de 10,5 a 1.290,0 cm³ (média de 189,65 cm³. Nos planejamentos 2D foi utilizado, em média, um total de 59,33 campos, e nos planejamentos 3D, 75,65 campos. Em todas as situações analisadas houve significante (p OBJECTIVE: To compare and quantify irradiated lung volumes using two-dimensional (2D and three-dimensional (3D conformal planning for radiotherapy in the treatment of lung cancer. MATERIALS AND METHODS: 2D and 3D conformal radiotherapy plannings were performed for 27 patients with lung cancer. Prescribed doses ranged from 45 to 66 Gy. The analysis covered the doses to planning target volume (PTV, gross tumor volume (GTV and lungs (lung volume receiving 20 Gy or 30 Gy - V20 and V30, respectively, and mean dose. The doses to adjacent organs at risk (spinal cord, esophagus and heart were maintained below the tolerance limits. RESULTS: GTV ranged from 10.5 to 1,290.0 cm³ (mean, 189.65 cm³. On average, a total of 59.33 fields were utilized in the 2D planning and 75.65 fields in the 3D planning. Lung volumes were significantly preserved (P < 0.05 with the 3D conformal planning in all the evaluated cases, with about 15% decrease in the irradiated lung volumes. Lungs without tumor were most benefited from this technique. CONCLUSION: 3D radiotherapy allowed a better

  18. Dose conformity of gamma knife radiosurgery and risk factors for complications

    International Nuclear Information System (INIS)

    Nakamura, Jean L.; Verhey, Lynn J.; Smith, Vernon; Petti, Paula L.; Lamborn, Kathleen R.; Larson, David A.; Wara, William M.; McDermott, Michael W.; Sneed, Penny K.

    2001-01-01

    Purpose: To quantitatively evaluate dose conformity achieved using Gamma Knife radiosurgery, compare results with those reported in the literature, and evaluate risk factors for complications. Methods and Materials: All lesions treated at our institution with Gamma Knife radiosurgery from May 1993 (when volume criteria were routinely recorded) through December 1998 were reviewed. Lesions were excluded from analysis for reasons listed below. Conformity index (the ratio of prescription volume to target volume) was calculated for all evaluable lesions and for lesions comparable to those reported in the literature on conformity of linac radiosurgery. Univariate Cox regression models were used to test for associations between treatment parameters and toxicity. Results: Of 1612 targets treated in 874 patients, 274 were excluded, most commonly for unavailability of individual prescription volume data because two or more lesions were included within the same dose matrix (176 lesions), intentional partial coverage for staged treatment of large arteriovenous malformations (AVMs) (33 lesions), and missing target volume data (26 lesions). The median conformity indices were 1.67 for all 1338 evaluable lesions and 1.40-1.43 for lesions comparable to two linac radiosurgery series that reported conformity indices of 1.8 and 2.7, respectively. Among all 651 patients evaluable for complications, there were one Grade 5, eight Grade 4, and 27 Grade 3 complications. Increased risk of toxicity was associated with larger target volume, maximum lesion diameter, prescription volume, or volume of nontarget tissue within the prescription volume. Conclusions: Gamma Knife radiosurgery achieves much more conformal dose distributions than those reported for conventional linac radiosurgery and somewhat more conformal dose distributions than sophisticated linac radiosurgery techniques. Larger target, nontarget, or prescription volumes are associated with increased risk of toxicity

  19. Late rectal toxicity: dose-volume effects of conformal radiotherapy for prostate cancer

    International Nuclear Information System (INIS)

    Huang, Eugene H.; Pollack, Alan; Levy, Larry; Starkschall, George; Lei Dong; Rosen, Isaac; Kuban, Deborah A.

    2002-01-01

    Purpose: To identify dosimetric, anatomic, and clinical factors that correlate with late rectal toxicity after three-dimensional conformal radiotherapy (3D-CRT) for prostate cancer. Methods and Materials: We retrospectively analyzed the dose-volume histograms and clinical records of 163 Stage T1b-T3c prostate cancer patients treated between 1992 and 1999 with 3D-CRT, to a total isocenter dose of 74-78 Gy at The University of Texas M. D. Anderson Cancer Center. The median follow-up was 62 months (range 24-102). All late rectal complications were scored using modified Radiation Therapy Oncology Group and Late Effects Normal Tissue Task Force criteria. The 6-year toxicity rate was assessed using Kaplan-Meier analysis and the log-rank test. A univariate proportional hazards regression model was used to test the correlation between Grade 2 or higher toxicity and the dosimetric, anatomic, and clinical factors. In a multivariate regression model, clinical factors were added to the dosimetric and anatomic variables to determine whether they significantly altered the risk of developing late toxicity. Results: At 6 years, the rate of developing Grade 2 or higher late rectal toxicity was 25%. A significant volume effect was observed at rectal doses of 60, 70, 75.6, and 78 Gy, and the risk of developing rectal complications increased exponentially as greater volumes were irradiated. Although the percentage of rectal volume treated correlated significantly with the incidence of rectal complications at all dose levels (p 3 of the rectum. Of the clinical variables tested, only a history of hemorrhoids correlated with rectal toxicity (p=0.003). Multivariate analysis showed that the addition of hemorrhoids increased the risk of toxicity for each dosimetric variable found to be significant on univariate analysis (p<0.05 for all comparisons). Conclusion: Dose-volume histogram analyses clearly indicated a volume effect on the probability of developing late rectal complications

  20. Independent dose calculation of the Tps Iplan in radiotherapy conformed with MLC; Calculo independiente de dosis del TPS Iplan en radioterapia conformada con MLC

    Energy Technology Data Exchange (ETDEWEB)

    Adrada, A.; Tello, Z.; Medina, L.; Garrigo, E.; Venencia, D., E-mail: jorge.alberto.adrada@gmail.com [Instituto Privado de Radioterapia, Obispo Oro 423, X5000BFI Cordoba (Argentina)

    2014-08-15

    The systems utilization of independent dose calculation in three dimensional-Conformal Radiation Therapy (3D-Crt) treatments allows a direct verification of the treatments times. The utilization of these systems allows diminishing the probability of errors occurrence generated by the treatment planning system (Tps), allowing a detailed analysis of the dose to delivering and review of the normalization point (Np) or prescription. The independent dose calculation is realized across the knowledge of dosimetric parameters of the treatment machine and particular characteristics of every individual field. The aim of this work is develops a calculation system of punctual doses for isocentric fields conformed with multi-leaf collimation systems (MLC), where the dose calculation is in conformity with the suggested ones by ICRU Report No. 42, 1987. Calculation software was realized in C ++ under a free platform of programming (Code::Blocks). The system uses files in format Rtp, exported from the Tps to systems of record and verification (Lantis). This file contains detailed information of the dose, Um, position of the MLC sheets and collimators for every field of treatment. The size of equivalent field is obtained from the positions of every sheet; the effective depth of calculation can be introduced from the dosimetric report of the Tps or automatically from the DFS of the field. The 3D coordinates of the isocenter and the Np for the treatment plan must be introduced manually. From this information the system looks the dosimetric parameters and calculates the Um. The calculations were realized in two accelerators a NOVALIS Tx (Varian) with 120 sheets of high definition (hd-MLC) and a PRIMUS Optifocus (Siemens) with 82 sheets. 705 patients were analyzed for a total of 1082, in plans made for both equipment s, the average uncertainty with regard to the calculation of the Tps is-0.43% ± 2.42% in a range between [-7.90 %, 7.50 %]. The major uncertainty was in Np near of the

  1. Secure data storage by three-dimensional absorbers in highly scattering volume medium

    International Nuclear Information System (INIS)

    Matoba, Osamu; Matsuki, Shinichiro; Nitta, Kouichi

    2008-01-01

    A novel data storage in a volume medium with highly scattering coefficient is proposed for data security application. Three-dimensional absorbers are used as data. These absorbers can not be measured by interferometer when the scattering in a volume medium is strong enough. We present a method to reconstruct three-dimensional absorbers and present numerical results to show the effectiveness of the proposed data storage.

  2. Highly ordered three-dimensional macroporous carbon spheres for determination of heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuxiao; Zhang, Jianming [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Huang, Hui [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China)

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer Highly ordered three dimensional macroporous carbon spheres (MPCSs) were prepared. Black-Right-Pointing-Pointer MPCS was covalently modified by cysteine (MPCS-CO-Cys). Black-Right-Pointing-Pointer MPCS-CO-Cys was first time used in electrochemical detection of heavy metal ions. Black-Right-Pointing-Pointer Heavy metal ions such as Pb{sup 2+} and Cd{sup 2+} can be simultaneously determined. -- Abstract: An effective voltammetric method for detection of trace heavy metal ions using chemically modified highly ordered three dimensional macroporous carbon spheres electrode surfaces is described. The highly ordered three dimensional macroporous carbon spheres were prepared by carbonization of glucose in silica crystal bead template, followed by removal of the template. The highly ordered three dimensional macroporous carbon spheres were covalently modified by cysteine, an amino acid with high affinities towards some heavy metals. The materials were characterized by physical adsorption of nitrogen, scanning electron microscopy, and transmission electron microscopy techniques. While the Fourier-transform infrared spectroscopy was used to characterize the functional groups on the surface of carbon spheres. High sensitivity was exhibited when this material was used in electrochemical detection (square wave anodic stripping voltammetry) of heavy metal ions due to the porous structure. And the potential application for simultaneous detection of heavy metal ions was also investigated.

  3. On the conformal higher spin unfolded equation for a three-dimensional self-interacting scalar field

    Energy Technology Data Exchange (ETDEWEB)

    Nilsson, Bengt E.W. [Fundamental Physics, Chalmers University of Technology,SE-412 96 Göteborg (Sweden)

    2016-08-24

    We propose field equations for the conformal higher spin system in three dimensions coupled to a conformal scalar field with a sixth order potential. Both the higher spin equation and the unfolded equation for the scalar field have source terms and are based on a conformal higher spin algebra which we treat as an expansion in multi-commutators. Explicit expressions for the source terms are suggested and subjected to some simple tests. We also discuss a cascading relation between the Chern-Simons action for the higher spin gauge theory and an action containing a term for each spin that generalizes the spin 2 Chern-Simons action in terms of the spin connection expressed in terms of the frame field. This cascading property is demonstrated in the free theory for spin 3 but should work also in the complete higher spin theory.

  4. Conformational analysis by intersection: CONAN.

    Science.gov (United States)

    Smellie, Andrew; Stanton, Robert; Henne, Randy; Teig, Steve

    2003-01-15

    As high throughput techniques in chemical synthesis and screening improve, more demands are placed on computer assisted design and virtual screening. Many of these computational methods require one or more three-dimensional conformations for molecules, creating a demand for a conformational analysis tool that can rapidly and robustly cover the low-energy conformational spaces of small molecules. A new algorithm of intersection is presented here, which quickly generates (on average heuristics are applied after intersection to generate a small representative collection of conformations that span the conformational space. In a study of approximately 97,000 randomly selected molecules from the MDDR, results are presented that explore these conformations and their ability to cover low-energy conformational space. Copyright 2002 Wiley Periodicals, Inc. J Comput Chem 24: 10-20, 2003

  5. Comparison of dose-volume histograms for Tomo therapy, linear accelerator-based 3D conformal radiation therapy, and intensity-modulated radiation therapy

    International Nuclear Information System (INIS)

    Ji, Youn-Sang; Dong, Kyung-Rae; Kim, Chang-Bok; Choi, Seong-Kwan; Chung, Woon-Kwan; Lee, Jong-Woong

    2011-01-01

    Highlights: → Evaluation of DVH from 3D CRT, IMRT and Tomo therapy was conducted for tumor therapy. → The doses of GTV and CTV were compared using DVHs from 3D CRT, IMRT and Tomo therapy. → The GTV was higher when Tomo therapy was used, while the doses of critical organ were low. → They said that Tomo therapy satisfied the goal of radiation therapy more than the others. - Abstract: Evaluation of dose-volume histograms from three-dimensional conformal radiation therapy (3D CRT), intensity-modulated radiation therapy (IMRT), and Tomo therapy was conducted. These three modalities are among the diverse treatment systems available for tumor therapy. Three patients who received tumor therapy for a malignant oligodendroglioma in the cranium, nasopharyngeal carcinoma in the cervical neck, and prostate cancer in the pelvis were selected as study subjects. Therapy plans were made for the three patients before dose-volume histograms were obtained. The doses of the gross tumor volume (GTV) and the clinical target volume (CTV) were compared using the dose-volume histograms obtained from the LINAC-based 3D CRT, IMRT planning station (Varian Eclipse-Varian, version 8.1), and Tomo therapy planning station. In addition, the doses of critical organs in the cranium, cervix, and pelvis that should be protected were compared. The GTV was higher when Tomo therapy was used compared to 3D CRT and the LINAC-based IMRT, while the doses of critical organ tissues that required protection were low. These results demonstrated that Tomo therapy satisfied the ultimate goal of radiation therapy more than the other therapies.

  6. Dosimetric comparison of standard bi-dimensional radiotherapy, mono-isocentric three-dimensional and arc-therapy for a bilateral breast cancer case with ganglionary attack; Comparaison dosimetrique pour un cas de cancer du sein bilateral avec atteinte ganglionnaire de la radiotherapie bidimensionnelle standard, la radiotherapie tridimensionnelle mono-isocentrique et l'arctherapie

    Energy Technology Data Exchange (ETDEWEB)

    Arnaud, A. [Centre Leon-Berard, Lyon (France); Bodez, V.; Alric, K.; Chastel, D.; Mege, A. [Institut Sainte-Catherine, Avignon (France)

    2011-10-15

    The authors report a study which aimed at determining the optimal radiotherapy technique for a patient operated from a bilateral breast cancer with ganglionary attack and peculiar thoracic conformation. A dosimetric study has been performed. Target volumes and lung and heart coverages have been compared for three techniques: bi-dimensional and three-dimensional radiotherapy, and arc-therapy. It appears that arc-therapy would allow a dosimetric and therapeutic duration gain without improving the target volume coverage while increasing doses delivered to organs at risk. Short communication

  7. Conformation radiotherapy and conformal radiotherapy

    International Nuclear Information System (INIS)

    Morita, Kozo

    1999-01-01

    In order to coincide the high dose region to the target volume, the 'Conformation Radiotherapy Technique' using the multileaf collimator and the device for 'hollow-out technique' was developed by Prof. S. Takahashi in 1960. This technique can be classified a type of 2D-dynamic conformal RT techniques. By the clinical application of this technique, the late complications of the lens, the intestine and the urinary bladder after radiotherapy for the maxillary cancer and the cervical cancer decreased. Since 1980's the exact position and shape of the tumor and the surrounding normal tissues can be easily obtained by the tremendous development of the CT/MRI imaging technique. As a result, various kinds of new conformal techniques such as the 3D-CRT, the dose intensity modulation, the tomotherapy have been developed since the beginning of 1990'. Several 'dose escalation study with 2D-/3D conformal RT' is now under way to improve the treatment results. (author)

  8. Three-dimensional true FISP for high-resolution imaging of the whole brain

    International Nuclear Information System (INIS)

    Schmitz, B.; Hagen, T.; Reith, W.

    2003-01-01

    While high-resolution T1-weighted sequences, such as three-dimensional magnetization-prepared rapid gradient-echo imaging, are widely available, there is a lack of an equivalent fast high-resolution sequence providing T2 contrast. Using fast high-performance gradient systems we show the feasibility of three-dimensional true fast imaging with steady-state precession (FISP) to fill this gap. We applied a three-dimensional true-FISP protocol with voxel sizes down to 0.5 x 0.5 x 0.5 mm and acquisition times of approximately 8 min on a 1.5-T Sonata (Siemens, Erlangen, Germany) magnetic resonance scanner. The sequence was included into routine brain imaging protocols for patients with cerebrospinal-fluid-related intracranial pathology. Images from 20 patients and 20 healthy volunteers were evaluated by two neuroradiologists with respect to diagnostic image quality and artifacts. All true-FISP scans showed excellent imaging quality free of artifacts in patients and volunteers. They were valuable for the assessment of anatomical and pathologic aspects of the included patients. High-resolution true-FISP imaging is a valuable adjunct for the exploration and neuronavigation of intracranial pathologies especially if cerebrospinal fluid is involved. (orig.)

  9. Comparative evaluation of two dose optimization methods for image-guided, highly-conformal, tandem and ovoids cervix brachytherapy planning

    Science.gov (United States)

    Ren, Jiyun; Menon, Geetha; Sloboda, Ron

    2013-04-01

    Although the Manchester system is still extensively used to prescribe dose in brachytherapy (BT) for locally advanced cervix cancer, many radiation oncology centers are transitioning to 3D image-guided BT, owing to the excellent anatomy definition offered by modern imaging modalities. As automatic dose optimization is highly desirable for 3D image-based BT, this study comparatively evaluates the performance of two optimization methods used in BT treatment planning—Nelder-Mead simplex (NMS) and simulated annealing (SA)—for a cervix BT computer simulation model incorporating a Manchester-style applicator. Eight model cases were constructed based on anatomical structure data (for high risk-clinical target volume (HR-CTV), bladder, rectum and sigmoid) obtained from measurements on fused MR-CT images for BT patients. D90 and V100 for HR-CTV, D2cc for organs at risk (OARs), dose to point A, conformation index and the sum of dwell times within the tandem and ovoids were calculated for optimized treatment plans designed to treat the HR-CTV in a highly conformal manner. Compared to the NMS algorithm, SA was found to be superior as it could perform optimization starting from a range of initial dwell times, while the performance of NMS was strongly dependent on their initial choice. SA-optimized plans also exhibited lower D2cc to OARs, especially the bladder and sigmoid, and reduced tandem dwell times. For cases with smaller HR-CTV having good separation from adjoining OARs, multiple SA-optimized solutions were found which differed markedly from each other and were associated with different choices for initial dwell times. Finally and importantly, the SA method yielded plans with lower dwell time variability compared with the NMS method.

  10. Combination of Transarterial Chemoembolization and Three-Dimensional Conformal Radiotherapy for Hepatocellular Carcinoma With Inferior Vena Cava Tumor Thrombus

    International Nuclear Information System (INIS)

    Koo, Ja Eun; Kim, Jong Hoon; Lim, Young-Suk

    2010-01-01

    Purpose: To evaluate the effects of transarterial chemoembolization (TACE) and three-dimensional conformal radiotherapy (CRT) in patients with hepatocellular carcinoma (HCC) and inferior vena cava tumor thrombus (IVCTT). Methods and Materials: A total of 42 consecutive patients who underwent TACE and CRT (TACE+CRT group) for the treatment of HCC with IVCTT were prospectively enrolled from July 2004 to October 2006. As historical controls, 29 HCC patients with IVCTT who received TACE alone (TACE group) between July 2003 and June 2004 were included. CRT was designed to target only the IVCTT and to deliver a median total dose of 45 Gy (range, 28-50 Gy). Results: Most baseline characteristics of the two groups were similar (p > 0.05). The response and progression-free rates of IVCTT were significantly higher in the TACE+CRT group than in the TACE group (42.9% and 71.4% vs. 13.8% and 37.9%, respectively; p < 0.01 for both rates). Overall, patient survival was significantly higher in the TACE+CRT group than in the TACE group (p < 0.01), with a median survival time of 11.7 months and 4.7 months, respectively. Treatment with TACE+CRT (hazard ratio [HR] = 0.38; 95% confidence interval [CI], 0.20-0.71), progression of IVCTT (HR = 4.05; 95% CI, 2.00-8.21), Child-Pugh class B (HR = 3.44; 95% CI, 1.79-6.61), and portal vein invasion (HR = 2.31; 95% CI, 1.19-4.50) were identified as independent predictors of mortality by multivariable analysis. Conclusions: The combination of TACE and CRT is more effective in the control of IVCTT associated with HCC and improves patient survival compared with TACE alone.

  11. Evaluation of homogeneity and dose conformity in IMRT planning in prostate radiotherapy

    International Nuclear Information System (INIS)

    Lopes, Juliane S.; Leidens, Matheus; Estacio, Daniela R.; Razera, Ricardo A.Z.; Streck, Elaine E.; Silva, Ana M.M. da

    2015-01-01

    The goal of this study was to evaluate the dose distribution homogeneity and conformity of radiation therapy plans of prostate cancer using IMRT. Data from 34 treatment plans of Hospital Sao Lucas of PUCRS, where those plans were executed, were retrospectively analyzed. All of them were done with 6MV X-rays from a linear accelerator CLINAC IX, and the prescription doses varied between 60 and 74 Gy. Analyses showing the homogeneity and conformity indices for the dose distribution of those plans were made. During these analyses, some comparisons with the traditional radiation therapy planning technic, the 3D-CRT, were discussed. The results showed that there is no correlation between the prescribed dose and the homogeneity and conformity indices, indicating that IMRT works very well even for higher doses. Furthermore, a comparison between the results obtained and the recommendations of ICRU 83 was carried out. It has also been observed that the indices were really close to the ideal values. 82.4% of the cases showed a difference below 5% of the ideal value for the index of conformity, and 88.2% showed a difference below 10% for the homogeneity index. Concluding, it is possible to confirm the quality of the analyzed radiation therapy plans of prostate cancer using IMRT. (author)

  12. Interplanner variability in carrying out three-dimensional conformal radiation therapy for non-small-cell lung cancer

    International Nuclear Information System (INIS)

    Fimmell, N.; Laferlita, C.; Everitt, S.; Schneider-Kolsky, M.; Budd, R.; Kron, T.; Reynolds, J.; Ball, D.; Mac Manus, M.

    2008-01-01

    This study evaluated the variability among six radiation therapy planners in planning radiation treatment for four patients with lung cancer using two treatment protocols. The interplanner variability for target conformity and homogeneity was smaller than the variability among the patients and planning approaches. The same was found for the dose volume indices achieved for most critical structures, indicating that interplanner variability is not likely to be an important source of variation in radiotherapy studies if concise treatment protocols are followed.

  13. Conformal flight path symbology for head-up displays: Defining the distribution of visual attention in three-dimensional space

    Science.gov (United States)

    Ververs, Patricia May

    experimental findings. Attention was found to be more widely distributed in X-Y space when the pilots were flying with the conformal, tunnel-in-the-sky as compared to the partially conformal ILS (instrument landing system) symbology set. There was little evidence that the air-based navigation displays were supporting divided attention in three-dimensional space. The ground-based scene-linked (truly conformal) display indicated promising effects of dividing attention in depth without negative consequences to processing the near domain symbology. Event expectancy was found to modulate pilot performance in the detection of events both on the symbology and in the environment. The phenomenon known as cognitive tunneling is discussed as a possible cause of the inadequate response times in resolving the anomalous events.

  14. Optimized dose conformation of multi-leaf collimator fields

    International Nuclear Information System (INIS)

    Serago, Christopher F.; Buskirk, Steven J.; Foo, May L.; McLaughlin, Mark P.

    1996-01-01

    Purpose/Objective: Current commercially available multi-leaf collimators (MLC) have leaf widths of about 1 cm. These leaf widths may produce stepped dose gradients at the fields edges at the 50% dose level. Small local perturbations of the dose distribution from the prescribed/expected dose distribution may not be acceptable for some clinical applications. Improvements to the conformation of the MLC dose distribution may be achieved using multiple exposures per MLC field, with either shifting the table/patient position, or rotating the orientation of the MLC jaws between exposures. Material and Methods: Dose distributions for MLC, primary jaws only, and lead alloy block fields were measured with film dosimetry for 6 and 20 MV photon beams in a solid water phantom. Square, circular, and typical clinical prostate, brain, lung, esophagus, and head and neck fields were measured. MLC field shapes were produced using a commercial MLC with a leaf width of 1 cm at the treatment isocenter. The dose per MLC field was delivered in either single (conventional) or multiple exposures. The table(patient) position or the collimator rotation was shifted between exposures when multiple exposure MLC fields were used. Differences in the dose distribution were evaluated at the 90% and 50% isodose level. Displacements of the measured 50% isodose from the prescribed/expected 50% isodose were measured at 5 degree intervals. Results: Measurements of the penumbra at a 10 cm depth for square fields show that using double exposure MLC fields with .5 cm table index decreases the effective penumbra by 1 mm. For clinical shaped fields, displacements between the prescribed/expected 50% isodose and the measured 50% isodose for conventional single exposure MLC fields are measured to be as great as 9 mm, and discrepancies on the order of 5 to 6 mm are common. In contrast, the maximum displacement errors measured with multiple exposure MLC fields are less than 5 mm and rarely more than 4 mm. In some

  15. Stereotactic Ablative Body Radiation Therapy for Primary Kidney Cancer: A 3-Dimensional Conformal Technique Associated With Low Rates of Early Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Daniel, E-mail: daniel.pham@petermac.org [Department of Radiotherapy Services, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); Department of Medical Imaging and Radiation Sciences, Monash University, Melbourne, Victoria (Australia); Thompson, Ann [Department of Radiotherapy Services, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); Kron, Tomas [Department of Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Victoria (Australia); Foroudi, Farshad [Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Victoria (Australia); Department of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); Kolsky, Michal Schneider [Department of Medical Imaging and Radiation Sciences, Monash University, Melbourne, Victoria (Australia); Devereux, Thomas; Lim, Andrew [Department of Radiotherapy Services, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia); Siva, Shankar [Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Victoria (Australia); Department of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Victoria (Australia)

    2014-12-01

    Purpose: To describe our 3-dimensional conformal planning approaches and report early toxicities with stereotactic body radiation therapy for the management of primary renal cell carcinoma. Methods and Materials: This is an analysis of a phase 1 trial of stereotactic body radiation therapy for primary inoperable renal cell carcinoma. A dose of 42 Gy/3 fractions was prescribed to targets ≥5 cm, whereas for <5 cm 26 Gy/1 fraction was used. All patients underwent a planning 4-dimensional CT to generate a planning target volume (PTV) from a 5-mm isotropic expansion of the internal target volume. Planning required a minimum of 8 fields prescribing to the minimum isodose surrounding the PTV. Intermediate dose spillage at 50% of the prescription dose (R50%) was measured to describe the dose gradient. Early toxicity (<6 months) was scored using the Common Terminology Criteria for Adverse Events (v4.0). Results: From July 2012 to August 2013 a total of 20 patients (median age, 77 years) were recruited into a prospective clinical trial. Eleven patients underwent fractionated treatment and 9 patients a single fraction. For PTV targets <100 cm{sup 3} the median number of beams used was 8 (2 noncoplanar) to achieve an average R50% of 3.7. For PTV targets >100 cm{sup 3} the median beam number used was 10 (4 noncoplanar) for an average R50% value of 4.3. The R50% was inversely proportional to decreasing PTV volume (r=−0.62, P=.003) and increasing total beams used (r=−0.51, P=.022). Twelve of 20 patients (60%) suffered grade ≤2 early toxicity, whereas 8 of 20 patients (40%) were asymptomatic. Nausea, chest wall pain, and fatigue were the most common toxicities reported. Conclusion: A 3-dimensional conformal planning technique of 8-10 beams can be used to deliver highly tolerable stereotactic ablation to primary kidney targets with minimal early toxicities. Ongoing follow-up is currently in place to assess long-term toxicities and cancer control.

  16. Induction chemotherapy combined with three-dimensional conformal radiation therapy for locally advanced non-small cell lung cancer

    International Nuclear Information System (INIS)

    Zheng Aiqing; Yu Jinming; Zhao Xianguang; Wang Xuetao; Wei Guangsheng

    2005-01-01

    Objective: To evaluate the effect and complication of induction chemotherapy combined with three-dimensional conformal radiation therapy (3DCRT) for locally advanced non small cell lung cancer (NSCLC). Methods: Ninety-two such patients were randomized into radiation therapy alone group(RT-, 50 patients) and induction chemotherapy combined radiotherapy group (CMT-, 42 patients). The induction chemotherapy consisted of 2-4 cycles of platinum-based regimen. Results: The overall median survival time was 15 months with 12 months in the RT group and 18 months in the CMT group (P=0.014) respectively. The 1-year overall survival rates were 48.6% and 71.2% in RT and CMT group, respectively (P=0.004). The 2-year survival rates were 20.8% and 37.6% in RT and CMT group, respectively (P=0.041). Treatment was well tolerated and the toxicities were similar in either group. Conclusion: The addition of induction chemotherapy to 3DCRT takes a survival advantage over 3DCRT alone for Stage III NSCLC without increasing toxicities. (authors)

  17. A treatment planning study comparing whole breast radiation therapy against conformal, IMRT and tomotherapy for accelerated partial breast irradiation

    International Nuclear Information System (INIS)

    Oliver, Mike; Chen, Jeff; Wong, Eugene; Van Dyk, Jake; Perera, Francisco

    2007-01-01

    Purpose and background: Conventional early breast cancer treatment consists of a lumpectomy followed by whole breast radiation therapy. Accelerated partial breast irradiation (APBI) is an investigational approach to post-lumpectomy radiation for early breast cancer. The purpose of this study is to compare four external beam APBI techniques, including tomotherapy, with conventional whole breast irradiation for their radiation conformity index, dose homogeneity index, and dose to organs at risk. Methods and materials: Small-field tangents, three-dimensional conformal radiation therapy, intensity-modulated radiation therapy and helical tomotherapy were compared for each of 15 patients (7 right, 8 left). One radiation conformity and two dose homogeneity indices were used to evaluate the dose to the target. The mean dose to organs at risk was also evaluated. Results: All proposed APBI techniques improved the conformity index significantly over whole breast tangents while maintaining dose homogeneity and without a significant increase in dose to organs at risk. Conclusion: The four-field IMRT plan produced the best dosimetric results; however this technique would require appropriate respiratory motion management. An alternative would be to use a four-field conformal technique that is less sensitive to the effects of respiratory motion

  18. High-resolution coherent three-dimensional spectroscopy of Br2.

    Science.gov (United States)

    Chen, Peter C; Wells, Thresa A; Strangfeld, Benjamin R

    2013-07-25

    In the past, high-resolution spectroscopy has been limited to small, simple molecules that yield relatively uncongested spectra. Larger and more complex molecules have a higher density of peaks and are susceptible to complications (e.g., effects from conical intersections) that can obscure the patterns needed to resolve and assign peaks. Recently, high-resolution coherent two-dimensional (2D) spectroscopy has been used to resolve and sort peaks into easily identifiable patterns for molecules where pattern-recognition has been difficult. For very highly congested spectra, however, the ability to resolve peaks using coherent 2D spectroscopy is limited by the bandwidth of instrumentation. In this article, we introduce and investigate high-resolution coherent three-dimensional spectroscopy (HRC3D) as a method for dealing with heavily congested systems. The resulting patterns are unlike those in high-resolution coherent 2D spectra. Analysis of HRC3D spectra could provide a means for exploring the spectroscopy of large and complex molecules that have previously been considered too difficult to study.

  19. Comparison of two dimensional and three dimensional radiotherapy treatment planning in locally advanced non-small cell lung cancer treated with continuous hyperfractionated accelerated radiotherapy weekend less

    International Nuclear Information System (INIS)

    Wilson, Elena M.; Joy Williams, Frances; Ethan Lyn, Basil; Aird, Edwin G.A.

    2005-01-01

    Background and purpose: Patients with inoperable non-small cell lung cancer being treated with continuous hyperfractionated accelerated radiotherapy weekend less (CHARTWEL) were planned and treated with a three dimensional (3D) conformal protocol and comparison made with two dimensional (2D) planning, as used previously, to compare past practice and methods. Patients and methods: Twenty-four patients were planned initially using 3D and then replanned using a 2D system. The 2D plans were transferred onto the 3D system and recalculated. Dose volume histograms could then be constructed of planning target volumes for phases 1 and 2 (PTV 1 and 2, respectively), lung and spinal cord for the 2D plans and compared with the 3D plans. Results: There was a significantly lower absolute dose to the isocentre with 2D compared to 3D planning with dose reductions of 3.9% for phase 1, 4.4% for phase 2 and 4.7% for those treated with a single phase. Maximum dose to spinal cord was greater in 17 of the 24 2D plans with a median dose reduction of 0.82 Gy for 3D (P=0.04). The percentage volume of whole lung receiving ≥20 Gy (V 20 ) was greater in 16 of the 24 2D plans with a median reduction in V 20 of 2.4% for 3D (P=0.03). Conclusions: A lower dose to tumour was obtained using 2D planning due to the method of dose calculation and spinal cord and lung doses were significantly higher

  20. Three-dimensional image reconstruction from stereo DSA

    International Nuclear Information System (INIS)

    Sakamoto, Kiyoshi; Kotoura, Noriko; Umehara, Takayoshi; Yamada, Eiji; Inaba, Tomohiro; Itou, Hiroshi

    1999-01-01

    The technique of interventional radiology has spread rapidly in recent years, and three-dimensional information from blood vessel images is being sought to enhance examinations. Stereo digital subtraction angiography (DSA) and rotational DSA were developed for that purpose. However, it is difficult with stereo DSA to observe the image pair during examination and to obtain positional information on blood vessels. Further, the exposure dose is increased in rotational DSA when many mask images need to be collected, and the patient is required to hold his or her breath for a long duration. We therefore devised a technique to construct three-dimensional blood vessel images by employing geometrical information extracted from stereo DSA images using the right and left images. We used a judgment method based on the correlation coefficient, although we had to extract an equal blood vessel from the right and left images to determine the three-dimensional coordinates of the blood vessel. The reconstructed three-dimensional blood vessels were projected from various angles, again by using a virtual focus, and new images were created. These image groups were displayed as rotational images by the animation display function incorporated in the DSA device. This system can observe blood vessel images of the same phase at a free angle, although the image quality is inferior to that of rotational DSA. In addition, because collection of the mask images is reduced, exposure dose can be decreased. Further, the system offers enhanced safety because no mechanical movement of the imaging system is involved. (author)

  1. Three-dimensional structures of the mammalian multidrug resistance P-glycoprotein demonstrate major conformational changes in the transmembrane domains upon nucleotide binding.

    Science.gov (United States)

    Rosenberg, Mark F; Kamis, Alhaji Bukar; Callaghan, Richard; Higgins, Christopher F; Ford, Robert C

    2003-03-07

    P-glycoprotein is an ATP-binding cassette transporter that is associated with multidrug resistance and the failure of chemotherapy in human patients. We have previously shown, based on two-dimensional projection maps, that P-glycoprotein undergoes conformational changes upon binding of nucleotide to the intracellular nucleotide binding domains. Here we present the three-dimensional structures of P-glycoprotein in the presence and absence of nucleotide, at a resolution limit of approximately 2 nm, determined by electron crystallography of negatively stained crystals. The data reveal a major reorganization of the transmembrane domains throughout the entire depth of the membrane upon binding of nucleotide. In the absence of nucleotide, the two transmembrane domains form a single barrel 5-6 nm in diameter and about 5 nm deep with a central pore that is open to the extracellular surface and spans much of the membrane depth. Upon binding nucleotide, the transmembrane domains reorganize into three compact domains that are each 2-3 nm in diameter and 5-6 nm deep. This reorganization opens the central pore along its length in a manner that could allow access of hydrophobic drugs (transport substrates) directly from the lipid bilayer to the central pore of the transporter.

  2. 3-D conformal HDR brachytherapy as monotherapy for localized prostate cancer. A pilot study

    International Nuclear Information System (INIS)

    Martin, T.; Baltas, D.; Kurek, R.; Roeddiger, S.; Kontova, M.; Anagnostopoulos, G.; Skazikis, G.; Zamboglou, N.; Dannenberg, T.; Buhleier, T.; Tunn, U.

    2004-01-01

    Purpose: pilot study to evaluate feasibility, acute toxicity and conformal quality of three-dimensional (3-D) conformal high-dose-rate (HDR) brachytherapy as monotherapy for localized prostate cancer using intraoperative real-time planning. Patients and methods: between 05/2002 and 05/2003, 52 patients with prostate cancer, prostate-specific antigen (PSA) ≤ 10 ng/ml, Gleason score ≤ 7 and clinical stage ≤ T2a were treated. Median PSA was 6.4 ng/ml and median Gleason score 5. 24/52 patients had stage T1c and 28/52 stage T2a. For transrectal ultrasound-(TRUS-)guided transperineal implantation of flexible plastic needles into the prostate, the real-time HDR planning system SWIFT trademark was used. After implantation, CT-based 3-D postplanning was performed. All patients received one implant for four fractions of HDR brachytherapy in 48 h using a reference dose (D ref ) of 9.5 Gy to a total dose of 38.0 Gy. Dose-volume histograms (DVHs) were analyzed to evaluate the conformal quality of each implant using D 90 , D 10 urethra, and D 10 rectum. Acute toxicity was evaluated using the CTC (common toxicity criteria) scales. Results: median D 90 was 106% of D ref (range: 93-115%), median D 10 urethra 159% of D ref (range: 127-192%), and median D 10 rectum 55% of D ref (range: 35-68%). Median follow-up is currently 8 months. In 2/52 patients acute grade 3 genitourinary toxicity was observed. No gastrointestinal toxicity > grade 1 occurred. Conclusion: 3-D conformal HDR brachytherapy as monotherapy using intraoperative real-time planning is a feasible and highly conformal treatment for localized prostate cancer associated with minimal acute toxicity. Longer follow-up is needed to evaluate late toxicity and biochemical control. (orig.)

  3. Three-dimensional nanostructure determination from a large diffraction data set recorded using scanning electron nanodiffraction

    Directory of Open Access Journals (Sweden)

    Yifei Meng

    2016-09-01

    Full Text Available A diffraction-based technique is developed for the determination of three-dimensional nanostructures. The technique employs high-resolution and low-dose scanning electron nanodiffraction (SEND to acquire three-dimensional diffraction patterns, with the help of a special sample holder for large-angle rotation. Grains are identified in three-dimensional space based on crystal orientation and on reconstructed dark-field images from the recorded diffraction patterns. Application to a nanocrystalline TiN thin film shows that the three-dimensional morphology of columnar TiN grains of tens of nanometres in diameter can be reconstructed using an algebraic iterative algorithm under specified prior conditions, together with their crystallographic orientations. The principles can be extended to multiphase nanocrystalline materials as well. Thus, the tomographic SEND technique provides an effective and adaptive way of determining three-dimensional nanostructures.

  4. Prediction of radiation-induced liver disease by Lyman normal-tissue complication probability model in three-dimensional conformal radiation therapy for primary liver carcinoma

    International Nuclear Information System (INIS)

    Xu ZhiYong; Liang Shixiong; Zhu Ji; Zhu Xiaodong; Zhao Jiandong; Lu Haijie; Yang Yunli; Chen Long; Wang Anyu; Fu Xiaolong; Jiang Guoliang

    2006-01-01

    Purpose: To describe the probability of RILD by application of the Lyman-Kutcher-Burman normal-tissue complication (NTCP) model for primary liver carcinoma (PLC) treated with hypofractionated three-dimensional conformal radiotherapy (3D-CRT). Methods and Materials: A total of 109 PLC patients treated by 3D-CRT were followed for RILD. Of these patients, 93 were in liver cirrhosis of Child-Pugh Grade A, and 16 were in Child-Pugh Grade B. The Michigan NTCP model was used to predict the probability of RILD, and then the modified Lyman NTCP model was generated for Child-Pugh A and Child-Pugh B patients by maximum-likelihood analysis. Results: Of all patients, 17 developed RILD in which 8 were of Child-Pugh Grade A, and 9 were of Child-Pugh Grade B. The prediction of RILD by the Michigan model was underestimated for PLC patients. The modified n, m, TD 5 (1) were 1.1, 0.28, and 40.5 Gy and 0.7, 0.43, and 23 Gy for patients with Child-Pugh A and B, respectively, which yielded better estimations of RILD probability. The hepatic tolerable doses (TD 5 ) would be MDTNL of 21 Gy and 6 Gy, respectively, for Child-Pugh A and B patients. Conclusions: The Michigan model was probably not fit to predict RILD in PLC patients. A modified Lyman NTCP model for RILD was recommended

  5. Three dimensional illustrating - three-dimensional vision and deception of sensibility

    Directory of Open Access Journals (Sweden)

    Anita Gánóczy

    2009-03-01

    Full Text Available The wide-spread digital photography and computer use gave the opportunity for everyone to make three-dimensional pictures and to make them public. The new opportunities with three-dimensional techniques give chance for the birth of new artistic photographs. We present in detail the biological roots of three-dimensional visualization, the phenomena of movement parallax, which can be used efficiently in making three-dimensional graphics, the Zöllner- and Corridor-illusion. There are present in this paper the visual elements, which contribute to define a plane two-dimensional image in three-dimension: coherent lines, the covering, the measurement changes, the relative altitude state, the abatement of detail profusion, the shadings and the perspective effects of colors.

  6. Risk factors of radiation-induced liver disease after three-dimensional conformal radiotherapy for primary liver carcinoma

    International Nuclear Information System (INIS)

    Liang Shixiong; Zhu Xiaodong; Lu Haijie; Pan Chaoyang; Huang Qifang; Li Fuxiang; Wang Anyu; Liang Guoliang; Fu Xiaolong

    2005-01-01

    Objective: To identify the risk factors of radiation-induced liver disease (RILD) after three-dimensional radiotherapy (3DCRT) for primary liver carcinoma (PLC) and the dosimetric threshold of RILD. Methods: Between April 1999 and August 2003, 128 PLC patients who were treated with 3DCRT received a mean dose of 53.6 ± 6.6 Gy with a 4-8 Gy/f, 3f/w, qod regimen. The relation between RILD and the possible clinical factors, such as gender, age, UICC/ AJCC T stage, GTV, HBV status, PTV, TACE, Child-Pugh grade of liver cirrhosis, BED calculated by LQ model and fraction size were analyzed. Among 84 patients who had full dose- volume histogram (DVH) data, the relation between RILD and dosimetric parameters were analyzed. Results: Nineteen patients (14.8%) developed RILD. It was found that T stage, GTV, PTV, Child-Pugh grade of liver cirrhosis and the acute hepatic toxicity proposed by common toxicity criteria version 2.0 (CTC2.0) were correlated with RILD (P=0.024, 0.002, 0.001, 0.000, 0.000, respectively). Multivariate analysis showed that only the Child-Pugh grade of liver cirrhosis was independent factor (P=0.000). The mean liver dose was significantly higher in patients with RILD (P=0.027). In patients with Child-Pugh grade A, V5 (percentage of normal liver volume with radiation dose > 5 Gy), V 10 and V 20 ≤81%, 69% and 42%, mean liver dose ≤28 Gy, RILD was not observed, whereas in patients with Child-Pugh grade B, the possibility of developing RILD was 53.3%(8/15). Conclusions: Comprehensive consideration of T stage, GTV, PTV and Child-Pugh grade of liver cirrhosis, especially the Child-Pugh grade of liver cirrhosis, when planning 3DCRT for PLC, may lower the incidence of RILD. (authors)

  7. Evaluation of the dose distribution of dynamic conical conformal therapy using a C-arm mounted accelerator

    International Nuclear Information System (INIS)

    Nakagawa, Keiichi; Aoki, Yukimasa; Ohtomo, Kuni

    2001-01-01

    Conformal radiation therapy, which is widely utilized in Japan as a standard, highly precise technique has limited advantage in dose confinement because of its coplanar beam entry. An improved form of conformal therapy is delivered by a linac mounted on a C-arm rotatable gantry. The linac head was designed to move along the C-arm with a maximum angle of 60 degrees. Simultaneous rotation of the gantry creates a Dynamic Conical irradiation technique. Dynamic Conical Conformal Therapy (Dyconic Therapy) was developed by combining the technique with continuous MLC motion based on beam's eye views of the target volume. Dose distributions were measured in a phantom using film densitometry and compared with conventional conformal radiation therapy. The measurements showed that the dose distribution conformed to the target shape identified by CT. In addition, the dose distribution for a cancer patient was evaluated through the use of DVHs generated by a treatment planning system. These measurements showed that the dose distribution along the patient's long axis conformed to the shape of the target volume. DVH analysis, however, did not indicate superiority of the present technique over the conventional technique. Angulation of the C-arm gantry allowed the primary beam to strike a larger area of the therapy room. This necessitated adding shielding to the walls and ceiling of the treatment room. It was confirmed that the leakage radiation was reduced to a negligible level by adding an iron plate 20 cm thick to several places on the side walls, by adding an iron plate 9 cm thick to several places on the ceiling, and by increasing the thickness of the concrete ceiling from 70 to 140 cm. The possible usefulness of Dyconic Therapy was confirmed. (author)

  8. Twistors and four-dimensional conformal field theory

    International Nuclear Information System (INIS)

    Singer, M.A.

    1990-01-01

    This is a report (with technical details omitted) on work concerned with generalizations to four dimensions of two-dimensional Conformed Field Theory. Accounts of this and related material are contained elsewhere. The Hilbert space of the four-dimensional theory has a natural interpretation in terms of massless spinor fields on real Minkowski space. From the twistor point of view this follows from the boundary CR-manifold P being precisely the space of light rays in real compactified Minkowski space. All the amplitudes can therefore be regarded as defined on Hilbert spaces built from Lorentzian spinor fields. Thus the twistor picture provides a kind of halfway house between the Lorentzian and Euclidean field theories. (author)

  9. An Individualized 3-Dimensional Designed and Printed Conformer After Dermis Fat Grafting for Complex Sockets.

    Science.gov (United States)

    Mourits, Daphne L; Remmers, Jelmer S; Tan, Stevie H; Moll, Annette C; Hartong, Dyonne T

    2018-04-03

    To introduce a novel technique to design individually customized conformers for postenucleation sockets with dermis fat implants. We use a 3-dimensional scan of the frontal face/orbit and eyelid contour to design an individualized conformer. This polymethylmetacrylate printed conformer is adapted to patients' socket, palpebral fissures, horizontal eyelid aperture, curvature of the eyelids, and mean diameter of patients' contralateral eye. Sutures through holes in the inferior part of the conformer and in the extension can be placed to fixate the conformer and anchor fornix deepening sutures. A correct fitting conformer can be printed and attached to the socket and eyelids. The shape of this conformer can be used subsequently postsurgically to design the ocular prosthesis. Presurgical planning is important to anticipate for a functional socket to adequately fit an artificial eye. The presented technique using 3-dimensional imaging, designing, and printing promises to prevent conformer extrusion and forniceal shortening.

  10. Three-dimensional Finite Elements Method simulation of Total Ionizing Dose in 22 nm bulk nFinFETs

    Energy Technology Data Exchange (ETDEWEB)

    Chatzikyriakou, Eleni, E-mail: ec3g12@soton.ac.uk; Potter, Kenneth; Redman-White, William; De Groot, C.H.

    2017-02-15

    Highlights: • Simulation of Total Ionizing Dose using the Finite Elements Method. • Carrier generation, transport and trapping in the oxide. • Application in three-dimensional bulk FinFET model of 22 nm node. • Examination of trapped charge in the Shallow Trench Isolation. • Trapped charge dependency of parasitic transistor current. - Abstract: Finite Elements Method simulation of Total Ionizing Dose effects on 22 nm bulk Fin Field Effect Transistor (FinFET) devices using the commercial software Synopsys Sentaurus TCAD is presented. The simulation parameters are extracted by calibrating the charge trapping model to experimental results on 400 nm SiO{sub 2} capacitors irradiated under zero bias. The FinFET device characteristics are calibrated to the Intel 22 nm bulk technology. Irradiation simulations of the transistor performed with all terminals unbiased reveal increased hardness up to a total dose of 1 MRad(SiO{sub 2}).

  11. Effects of three-dimensional conformal radiotherapy, indensity modulated radiotherapy, and conventional radiotherapy ON treatment of esophageal cancer

    Directory of Open Access Journals (Sweden)

    Jian-Jun Han

    2016-07-01

    Full Text Available Objective: To compare the irradiation volume, short-term and long-term efficacy of conventional radiotherapy (CR, three-dimensional conformal radiotherapy (3D-CRT, and indensity modulated radiotherapy (IMRT in the treatment of esophageal cancer. Methods: A retrospective analysis method was adopted. The patients were divided into CR group (n=42, 3D-CRT group (n=45, and IMRT group (n=40. A follow-up visit was paid to collect the short-term and long-term efficacy, and the occurrence of adverse reactions. The gross tumor voluem (GTV, clinical target volume (CTV, planning target volume (PTV, and irradiation volume of organs (bilateral lungs, spinal cord, and heart at risk (OAR in the three groups were compared. Results: It was found by target volume comparison that the mean values of GTV, CTV, and PTV in the three groups were significantly increased (P0.05. The occurrence rate of adverse reactions in 3D-CRT group and IMRT group was significantly lower than that in CR group (P0.05. The difference of 1-year survival rate among the three groups was not statistically significant (P=0.144, but 3-year and 5-year survival rates in 3D-CRT group and IMRT group were significantly higher than those in CR group (P<0.05. Conclusions: 3D-CRT and IMRT can significantly enhance the short-term and long-term efficacy for esophageal cancer patients, and alleviate the radioactive damage; therefore, they are deserved to be widely recommended in the clinic.

  12. Accuracy Assessment for the Three-Dimensional Coordinates by High-Speed Videogrammetric Measurement

    Directory of Open Access Journals (Sweden)

    Xianglei Liu

    2018-01-01

    Full Text Available High-speed CMOS camera is a new kind of transducer to make the videogrammetric measurement for monitoring the displacement of high-speed shaking table structure. The purpose of this paper is to validate the three-dimensional coordinate accuracy of the shaking table structure acquired from the presented high-speed videogrammetric measuring system. In the paper, all of the key intermediate links are discussed, including the high-speed CMOS videogrammetric measurement system, the layout of the control network, the elliptical target detection, and the accuracy validation of final 3D spatial results. Through the accuracy analysis, the submillimeter accuracy can be made for the final the three-dimensional spatial coordinates which certify that the proposed high-speed videogrammetric technique is a better alternative technique which can replace the traditional transducer technique for monitoring the dynamic response for the shaking table structure.

  13. Method of solving conformal models in D-dimensional space I

    International Nuclear Information System (INIS)

    Fradkin, E.S.; Palchik, M.Y.

    1996-01-01

    We study the Hilbert space of conformal field theory in D-dimensional space. The latter is shown to have model-independent structure. The states of matter fields and gauge fields form orthogonal subspaces. The dynamical principle fixing the choice of model may be formulated either in each of these subspaces or in their direct sum. In the latter case, gauge interactions are necessarily present in the model. We formulate the conditions specifying the class of models where gauge interactions are being neglected. The anomalous Ward identities are derived. Different values of anomalous parameters (D-dimensional analogs of a central charge, including operator ones) correspond to different models. The structure of these models is analogous to that of 2-dimensional conformal theories. Each model is specified by D-dimensional analog of null vector. The exact solutions of the simplest models of this type are examined. It is shown that these models are equivalent to Lagrangian models of scalar fields with a triple interaction. The values of dimensions of such fields are calculated, and the closed sets of differential equations for higher Green functions are derived. Copyright copyright 1996 Academic Press, Inc

  14. Conformal Nets II: Conformal Blocks

    Science.gov (United States)

    Bartels, Arthur; Douglas, Christopher L.; Henriques, André

    2017-08-01

    Conformal nets provide a mathematical formalism for conformal field theory. Associated to a conformal net with finite index, we give a construction of the `bundle of conformal blocks', a representation of the mapping class groupoid of closed topological surfaces into the category of finite-dimensional projective Hilbert spaces. We also construct infinite-dimensional spaces of conformal blocks for topological surfaces with smooth boundary. We prove that the conformal blocks satisfy a factorization formula for gluing surfaces along circles, and an analogous formula for gluing surfaces along intervals. We use this interval factorization property to give a new proof of the modularity of the category of representations of a conformal net.

  15. New three-dimensional moving field radiation therapy for brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Mitsuyama, Fuyuki; Kanno, Tetsuo; Nagata, Yutaka; Koga, Sukehiko [Fujita-Gakuen Health Univ., Toyoake, Aichi (Japan); Jain, V K

    1992-06-01

    A new modified rotation radiation method called 'three-dimensional moving field radiation therapy' is described. The new method uses rotation in many planes while maintaining the same isocenter to achieve a good spatial dose distribution. This delivers a high dose to tumors and spares the surrounding normal structures. This easy method can be carried out using the equipment for conventional rotation radiation therapy. The new method was superior to the one plane rotation radiation therapy using a physical phantom with film, a chemical phantom using the iodine-starch reaction, and a new biological model using tumor cells. Treatment of six brain tumors irradiated with total air doses of 50-60 Gy caused no hair loss or radiation necrosis. (author).

  16. A Retrospective Comparison of Robotic Stereotactic Body Radiotherapy and Three-Dimensional Conformal Radiotherapy for the Reirradiation of Locally Recurrent Nasopharyngeal Carcinoma

    International Nuclear Information System (INIS)

    Ozyigit, Gokhan; Cengiz, Mustafa; Yazici, Gozde; Yildiz, Ferah; Gurkaynak, Murat; Zorlu, Faruk; Yildiz, Demet; Hosal, Sefik; Gullu, Ibrahim; Akyol, Fadil

    2011-01-01

    Purpose: We assessed therapeutic outcomes of reirradiation with robotic stereotactic radiotherapy (SBRT) for locally recurrent nasopharyngeal carcinoma (LRNPC) patients and compared those results with three-dimensional conformal radiotherapy (CRT) with or without brachytherapy (BRT). Methods and Materials: Treatment outcomes were evaluated retrospectively in 51 LRNPC patients receiving either robotic SBRT (24 patients) or CRT with or without BRT (27 patients) in our department. CRT was delivered with a 6-MV linear accelerator, and a median total reirradiation dose of 57 Gy in 2 Gy/day was given. Robotic SBRT was delivered with CyberKnife (Accuray, Sunnyvale, CA). Patients in the SBRT arm received 30 Gy over 5 consecutive days. We calculated actuarial local control and cancer-specific survival rates for the comparison of treatment outcomes in SBRT and CRT arms. The Common Terminology Criteria for Adverse Events v3.0 was used for toxicity evaluation. Results: The median follow-up was 24 months for all patients. Two-year actuarial local control rates were 82% and 80% for SBRT and CRT arms, respectively (p = 0.6). Two-year cancer-specific survival rates were 64% and 47% for the SBRT and CRT arms, respectively (p = 0.4). Serious late toxicities (Grade 3 and above) were observed in 21% of patients in the SBRT arm, whereas 48% of patients had serious toxicity in the CRT arm (p = 0.04). Fatal complications occurred in three patients (12.5%) of the SBRT arm, and four patients (14.8%) of the CRT arm (p = 0.8). T stage at recurrence was the only independent predictor for local control and survival. Conclusion: Our robotic SBRT protocol seems to be feasible and less toxic in terms of late effects compared with CRT arm for the reirradiation of LRNPC patients.

  17. Can All Centers Plan Intensity-Modulated Radiotherapy (IMRT) Effectively? An External Audit of Dosimetric Comparisons Between Three-Dimensional Conformal Radiotherapy and IMRT for Adjuvant Chemoradiation for Gastric Cancer

    International Nuclear Information System (INIS)

    Chung, Hans T.; Lee, Brian; Park, Eileen; Lu, Jiade J.; Xia Ping

    2008-01-01

    Purpose: To compare dosimetric endpoints between three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) at our center with limited IMRT experience, and to perform an external audit of the IMRT plans. Methods and Materials: Ten patients, who received adjuvant chemoradiation for gastric cancer, formed the study cohort. For standardization, the planning target volume (PTV) and organs at risk were recontoured with the assistance of a study protocol radiologic atlas. The cohort was replanned with CMS Xio to generate coplanar 3D-CRT and IMRT plans. All 10 datasets, including volumes but without the plans (i.e., blinded), were transmitted to an experienced center where IMRT plans were designed using Nomos Corvus (IMRT-C) and ADAC Pinnacle (IMRT-P). All IMRT plans were normalized to D95% receiving 45 Gy. Results: Intensity-modulated radiotherapy yielded higher PTV V45 (volume that receives ≥45 Gy) (p < 0.001) than 3D-CRT. No difference in V20 was seen in the right (p = 0.9) and left (p 0.3) kidneys, but the liver mean dose (p < 0.001) was superior with IMRT. For the external audit, IMRT-C (p = 0.002) and IMRT-P (p < 0.001) achieved significantly lower left kidney V20 than IMRT, and IMRT-P (p < 0.001) achieved lower right kidney V20 than IMRT. The IMRT-C (p = 0.003) but not IMRT-P (p = 0.6) had lower liver mean doses than IMRT. Conclusions: At our institution with early IMRT experience, IMRT improved PTV dose coverage and liver doses but not kidney doses. An external audit of IMRT plans showed that an experienced center can yield superior IMRT plans

  18. Three-Dimensional Electromagnetic High Frequency Axisymmetric Cavity Scars.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt

    2014-10-01

    This report examines the localization of high frequency electromagnetic fi elds in three-dimensional axisymmetric cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This report treats both the case where the opposing sides, or mirrors, are convex, where there are no interior foci, and the case where they are concave, leading to interior foci. The scalar problem is treated fi rst but the approximations required to treat the vector fi eld components are also examined. Particular att ention is focused on the normalization through the electromagnetic energy theorem. Both projections of the fi eld along the scarred orbit as well as point statistics are examined. Statistical comparisons are m ade with a numerical calculation of the scars run with an axisymmetric simulation. This axisymmetric cas eformstheoppositeextreme(wherethetwomirror radii at each end of the ray orbit are equal) from the two -dimensional solution examined previously (where one mirror radius is vastly di ff erent from the other). The enhancement of the fi eldontheorbitaxiscanbe larger here than in the two-dimensional case. Intentionally Left Blank

  19. Preliminary investigations on the determination of three-dimensional dose distributions using scintillator blocks and optical tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kroll, Florian; Karsch, Leonhard [OncoRay - National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, TU Dresden, 01307 Dresden (Germany); Pawelke, Jörg [OncoRay - National Center for Radiation Research in Oncology, Medical Faculty Carl Gustav Carus, TU Dresden, 01307 Dresden, Germany and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Radiation Physics, P.O. Box 510119, 01314 Dresden (Germany)

    2013-08-15

    Purpose: Clinical QA in teletherapy as well as the characterization of experimental radiation sources for future medical applications requires effective methods for measuring three-dimensional (3D) dose distributions generated in a water-equivalent medium. Current dosimeters based on ionization chambers, diodes, thermoluminescence detectors, radiochromic films, or polymer gels exhibit various drawbacks: High quality 3D dose determination is either very sophisticated and expensive or requires high amounts of effort and time for the preparation or read out. New detectors based on scintillator blocks in combination with optical tomography are studied, since they have the potential to facilitate the desired cost-effective, transportable, and long-term stable dosimetry system that is able to determine 3D dose distributions with high spatial resolution in a short time.Methods: A portable detector prototype was set up based on a plastic scintillator block and four digital cameras. During irradiation the scintillator emits light, which is detected by the fixed cameras. The light distribution is then reconstructed by optical tomography, using maximum-likelihood expectation maximization. The result of the reconstruction approximates the 3D dose distribution. First performance tests of the prototype using laser light were carried out. Irradiation experiments were performed with ionizing radiation, i.e., bremsstrahlung (6 to 21 MV), electrons (6 to 21 MeV), and protons (68 MeV), provided by clinical and research accelerators.Results: Laser experiments show that the current imaging properties differ from the design specifications: The imaging scale of the optical systems is position dependent, ranging from 0.185 mm/pixel to 0.225 mm/pixel. Nevertheless, the developed dosimetry method is proven to be functional for electron and proton beams. Induced radiation doses of 50 mGy or more made 3D dose reconstructions possible. Taking the imaging properties into account, determined

  20. Three-Dimensional, Transgenic Cell Models to Quantify Space Genotoxic Effects

    Science.gov (United States)

    Gonda, S. R.; Sognier, M. A.; Wu, H.; Pingerelli, P. L.; Glickman, B. W.; Dawson, David L. (Technical Monitor)

    1999-01-01

    The space environment contains radiation and chemical agents known to be mutagenic and carcinogenic to humans. Additionally, microgravity is a complicating factor that may modify or synergize induced genotoxic effects. Most in vitro models fail to use human cells (making risk extrapolation to humans more difficult), overlook the dynamic effect of tissue intercellular interactions on genotoxic damage, and lack the sensitivity required to measure low-dose effects. Currently a need exists for a model test system that simulates cellular interactions present in tissue, and can be used to quantify genotoxic damage induced by low levels of radiation and chemicals, and extrapolate assessed risk to humans. A state-of-the-art, three-dimensional, multicellular tissue equivalent cell culture model will be presented. It consists of mammalian cells genetically engineered to contain multiple copies of defined target genes for genotoxic assessment,. NASA-designed bioreactors were used to coculture mammalian cells into spheroids, The cells used were human mammary epithelial cells (H184135) and Stratagene's (Austin, Texas) Big Blue(TM) Rat 2 lambda fibroblasts. The fibroblasts were genetically engineered to contain -a high-density target gene for mutagenesis (60 copies of lacl/LacZ per cell). Tissue equivalent spheroids were routinely produced by inoculation of 2 to 7 X 10(exp 5) fibroblasts with Cytodex 3 beads (150 micrometers in diameter). at a 20:1 cell:bead ratio, into 50-ml HARV bioreactors (Synthecon, Inc.). Fibroblasts were cultured for 5 days, an equivalent number of epithelial cells added, and the fibroblast/epithelial cell coculture continued for 21 days. Three-dimensional spheroids with diameters ranging from 400 to 600 micrometers were obtained. Histological and immunohistochemical Characterization revealed i) both cell types present in the spheroids, with fibroblasts located primarily in the center, surrounded by epithelial cells; ii) synthesis of extracellular matrix

  1. Three-dimensional aromatic networks.

    Science.gov (United States)

    Toyota, Shinji; Iwanaga, Tetsuo

    2014-01-01

    Three-dimensional (3D) networks consisting of aromatic units and linkers are reviewed from various aspects. To understand principles for the construction of such compounds, we generalize the roles of building units, the synthetic approaches, and the classification of networks. As fundamental compounds, cyclophanes with large aromatic units and aromatic macrocycles with linear acetylene linkers are highlighted in terms of transannular interactions between aromatic units, conformational preference, and resolution of chiral derivatives. Polycyclic cage compounds are constructed from building units by linkages via covalent bonds, metal-coordination bonds, or hydrogen bonds. Large cage networks often include a wide range of guest species in their cavity to afford novel inclusion compounds. Topological isomers consisting of two or more macrocycles are formed by cyclization of preorganized species. Some complicated topological networks are constructed by self-assembly of simple building units.

  2. SU-E-T-243: MonteCarlo Simulation Study of Polymer and Radiochromic Gel for Three-Dimensional Proton Dose Distribution

    International Nuclear Information System (INIS)

    Park, M; Jung, H; Kim, G; Ji, Y; Kim, K; Park, S

    2014-01-01

    Purpose: To estimate the three dimensional dose distributions in a polymer gel and a radiochromic gel by comparing with the virtual water phantom exposed to proton beams by applying Monte Carlo simulation. Methods: The polymer gel dosimeter is the compositeness material of gelatin, methacrylic acid, hydroquinone, tetrakis, and distilled water. The radiochromic gel is PRESAGE product. The densities of polymer and radiochromic gel were 1.040 and 1.0005 g/cm3, respectively. The shape of water phantom was a hexahedron with the size of 13 × 13 × 15 cm3. The proton beam energies of 72 and 116 MeV were used in the simulation. Proton beam was directed to the top of the phantom with Z-axis and the shape of beam was quadrangle with 10 × 10 cm2 dimension. The Percent depth dose and the dose distribution were evaluated for estimating the dose distribution of proton particle in two gel dosimeters, and compared with the virtual water phantom. Results: The Bragg-peak for proton particles in two gel dosimeters was similar to the virtual water phantom. Bragg-peak regions of polymer gel, radiochromic gel, and virtual water phantom were represented in the identical region (4.3 cm) for 72 MeV proton beam. For 116 MeV proton beam, the Bragg-peak regions of polymer gel, radiochromic gel, and virtual water phantom were represented in 9.9, 9.9 and 9.7 cm, respectively. The dose distribution of proton particles in polymer gel, radiochromic gel, and virtual water phantom was approximately identical in the case of 72 and 116 MeV energies. The errors for the simulation were under 10%. Conclusion: This work indicates the evaluation of three dimensional dose distributions by exposing proton particles to polymer and radiochromic gel dosimeter by comparing with the water phantom. The polymer gel and the radiochromic gel dosimeter show similar dose distributions for the proton beams

  3. Electron tomography, three-dimensional Fourier analysis and colour prediction of a three-dimensional amorphous biophotonic nanostructure

    Science.gov (United States)

    Shawkey, Matthew D.; Saranathan, Vinodkumar; Pálsdóttir, Hildur; Crum, John; Ellisman, Mark H.; Auer, Manfred; Prum, Richard O.

    2009-01-01

    Organismal colour can be created by selective absorption of light by pigments or light scattering by photonic nanostructures. Photonic nanostructures may vary in refractive index over one, two or three dimensions and may be periodic over large spatial scales or amorphous with short-range order. Theoretical optical analysis of three-dimensional amorphous nanostructures has been challenging because these structures are difficult to describe accurately from conventional two-dimensional electron microscopy alone. Intermediate voltage electron microscopy (IVEM) with tomographic reconstruction adds three-dimensional data by using a high-power electron beam to penetrate and image sections of material sufficiently thick to contain a significant portion of the structure. Here, we use IVEM tomography to characterize a non-iridescent, three-dimensional biophotonic nanostructure: the spongy medullary layer from eastern bluebird Sialia sialis feather barbs. Tomography and three-dimensional Fourier analysis reveal that it is an amorphous, interconnected bicontinuous matrix that is appropriately ordered at local spatial scales in all three dimensions to coherently scatter light. The predicted reflectance spectra from the three-dimensional Fourier analysis are more precise than those predicted by previous two-dimensional Fourier analysis of transmission electron microscopy sections. These results highlight the usefulness, and obstacles, of tomography in the description and analysis of three-dimensional photonic structures. PMID:19158016

  4. Implementation of three-dimensional planning in brachytherapy of high dose rate for gynecology therapies; Implementacao de planejamento tridimensional em braquiterapia de alta taxa de dose para tratamentos ginecologicos

    Energy Technology Data Exchange (ETDEWEB)

    Sales, Camila Pessoa de

    2015-09-01

    This work aims to implement the three-dimensional (3D) planning for gynecological brachytherapy treatments. For this purpose, tests of acceptance and commissioning of brachytherapy equipment were performed to establish a quality and periodic assurance program. For this purpose, an important step was searching for a material to be used as a dummy source, since the applicators do not have any specific dummy. In addition, the validation of the use of applicators library was made for reconstruction in computed tomography (CT) and magnetic resonance imaging (MRI). In order to validate 3D planning, comparison of doses in dose assessment points used in bidimensional (2D) plans have been performed with volumetric doses to adjacent organs to the tumor. Finally, a protocol was established for 3D brachytherapy planning alternately using magnetic resonance image (MRI) and CT images, making evaluation of the dose in the tumor through the recording of MR and CT images. It was not possible to find a suitable material that could be used as dummy in MRI. However, the acquisition of the license's library for the applicators made possible the 3D planning based on MRI. No correlation was found between volumetric and specific doses analyzed, showing the importance of the implementation of 3D planning. The average ratio between D{sub 2cc} and ICRU{sub Bladder} dose was 1,74, 22% higher than the ratio found by others authors. For the rectum, D{sub 2cc} was less than dose point for 60% of fractions; the average difference was 12,5%. The average ratio between D{sub 2cc} and point dose rectum, 0,85, is equivalent to the value showed by Kim et al, 0,91. The D{sub 2cc} for sigmoid was 69% higher than point dose used, unless it was not possible compare this value, since the sigmoid point used in the 2D procedures is not used in others institutes. Relative dose in 2 cc of sigmoid was 57% of the prescription dose, the same value was found by in literature. This work enabled the

  5. Three-dimensional cluster formation and structure in heterogeneous dose distribution of intensity modulated radiation therapy.

    Science.gov (United States)

    Chao, Ming; Wei, Jie; Narayanasamy, Ganesh; Yuan, Yading; Lo, Yeh-Chi; Peñagarícano, José A

    2018-05-01

    To investigate three-dimensional cluster structure and its correlation to clinical endpoint in heterogeneous dose distributions from intensity modulated radiation therapy. Twenty-five clinical plans from twenty-one head and neck (HN) patients were used for a phenomenological study of the cluster structure formed from the dose distributions of organs at risks (OARs) close to the planning target volumes (PTVs). Initially, OAR clusters were searched to examine the pattern consistence among ten HN patients and five clinically similar plans from another HN patient. Second, clusters of the esophagus from another ten HN patients were scrutinized to correlate their sizes to radiobiological parameters. Finally, an extensive Monte Carlo (MC) procedure was implemented to gain deeper insights into the behavioral properties of the cluster formation. Clinical studies showed that OAR clusters had drastic differences despite similar PTV coverage among different patients, and the radiobiological parameters failed to positively correlate with the cluster sizes. MC study demonstrated the inverse relationship between the cluster size and the cluster connectivity, and the nonlinear changes in cluster size with dose thresholds. In addition, the clusters were insensitive to the shape of OARs. The results demonstrated that the cluster size could serve as an insightful index of normal tissue damage. The clinical outcome of the same dose-volume might be potentially different. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. An easy irradiation technique (partial half-beam) to reduce renal dose in radiotherapy of cervical cancer including paraaortic lymph nodes

    International Nuclear Information System (INIS)

    Vorwerk, H.; Wagner, D.; Christiansen, H.; Hess, C.F.; Hermann, R.M.

    2008-01-01

    Purpose: for radiation treatment of patients with cervical cancer and a high risk for paraaortic lymph node involvement, an easy three-dimensional (3-D) conformal irradiation technique (partial half-beam [PHB]) for protection of organs at risk, especially of renal tissue, was developed. Patients and methods: in five consecutive female patients a computed tomography scan was performed. Dose-volume histograms of the renal tissue and other organs at risk were analyzed for PHB, three other 3-D conformal techniques, and an intensity-modulated radiotherapy (IMRT) technique. Results: the PHB technique reduced the renal volume and volumes of other organs at risk exposed to radiation doses when comparing all patients to the other 3-D conformal techniques. With use of the IMRT technique more renal tissue volume received very low radiation doses (≤ 6.8 Gy) whereas the D 10 was lower than with the PHB technique. Conclusion: in female patients with cervical cancer and high risk for paraaortic lymph node involvement, the use of the PHB technique is recommended to reduce renal radiation exposure, if no IMRT technique should be applied. The PHB technique is very easily and fast applicable. (orig.)

  7. Evidence-based review of three-dimensional conformal radiotherapy for localized prostate cancer: An ASTRO outcomes initiative

    International Nuclear Information System (INIS)

    Morris, David E.; Emami, Bahman; Mauch, Peter M.; Konski, Andre A.; Tao, May L.; Ng, Andrea K.; Klein, Eric A.; Mohideen, Najeeb; Hurwitz, Mark D.; Fraas, Bendick A.; Roach, Mack; Gore, Elizabeth M.; Tepper, Joel E.

    2005-01-01

    Purpose: To perform a systematic review of the evidence to determine the efficacy and effectiveness of three-dimensional conformal radiotherapy (3D-CRT) for localized prostate cancer; provide a clear presentation of the key clinical outcome questions related to the use of 3D-CRT in the treatment of localized prostate cancer that may be answered by a formal literature review; and provide concise information on whether 3D-CRT improves the clinical outcomes in the treatment of localized prostate cancer compared with conventional RT. Methods and Materials: We performed a systematic review of the literature through a structured process developed by the American Society for Therapeutic Radiology and Oncology's Outcomes Committee that involved the creation of a multidisciplinary task force, development of clinical outcome questions, a formal literature review and data abstraction, data review, and outside peer review. Results: Seven key clinical questions were identified. The results and task force conclusions of the literature review for each question are reported. Conclusion: The technological goals of reducing morbidity with 3D-CRT have been achieved. Randomized trials and follow-up of completed trials remain necessary to address these clinical outcomes specifically with regard to patient subsets and the use of hormonal therapy

  8. A comprehensive dosimetric study of pancreatic cancer treatment using three-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated radiation therapy (VMAT), and passive-scattering and modulated-scanning proton therapy (PT)

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xuanfeng; Dionisi, Francesco; Tang, Shikui; Ingram, Mark; Hung, Chun-Yu; Prionas, Evangelos; Lichtenwalner, Phil; Butterwick, Ian; Zhai, Huifang; Yin, Lingshu; Lin, Haibo; Kassaee, Alireza; Avery, Stephen, E-mail: stephen.avery@uphs.upenn.edu

    2014-07-01

    With traditional photon therapy to treat large postoperative pancreatic target volume, it often leads to poor tolerance of the therapy delivered and may contribute to interrupted treatment course. This study was performed to evaluate the potential advantage of using passive-scattering (PS) and modulated-scanning (MS) proton therapy (PT) to reduce normal tissue exposure in postoperative pancreatic cancer treatment. A total of 11 patients with postoperative pancreatic cancer who had been previously treated with PS PT in University of Pennsylvania Roberts Proton Therapy Center from 2010 to 2013 were identified. The clinical target volume (CTV) includes the pancreatic tumor bed as well as the adjacent high-risk nodal areas. Internal (iCTV) was generated from 4-dimensional (4D) computed tomography (CT), taking into account target motion from breathing cycle. Three-field and 4-field 3D conformal radiation therapy (3DCRT), 5-field intensity-modulated radiation therapy, 2-arc volumetric-modulated radiation therapy, and 2-field PS and MS PT were created on the patients’ average CT. All the plans delivered 50.4 Gy to the planning target volume (PTV). Overall, 98% of PTV was covered by 95% of the prescription dose and 99% of iCTV received 98% prescription dose. The results show that all the proton plans offer significant lower doses to the left kidney (mean and V{sub 18} {sub Gy}), stomach (mean and V{sub 20} {sub Gy}), and cord (maximum dose) compared with all the photon plans, except 3-field 3DCRT in cord maximum dose. In addition, MS PT also provides lower doses to the right kidney (mean and V{sub 18} {sub Gy}), liver (mean dose), total bowel (V{sub 20} {sub Gy} and mean dose), and small bowel (V{sub 15} {sub Gy} absolute volume ratio) compared with all the photon plans and PS PT. The dosimetric advantage of PT points to the possibility of treating tumor bed and comprehensive nodal areas while providing a more tolerable treatment course that could be used for dose

  9. A comprehensive dosimetric study of pancreatic cancer treatment using three-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT), volumetric-modulated radiation therapy (VMAT), and passive-scattering and modulated-scanning proton therapy (PT)

    International Nuclear Information System (INIS)

    Ding, Xuanfeng; Dionisi, Francesco; Tang, Shikui; Ingram, Mark; Hung, Chun-Yu; Prionas, Evangelos; Lichtenwalner, Phil; Butterwick, Ian; Zhai, Huifang; Yin, Lingshu; Lin, Haibo; Kassaee, Alireza; Avery, Stephen

    2014-01-01

    With traditional photon therapy to treat large postoperative pancreatic target volume, it often leads to poor tolerance of the therapy delivered and may contribute to interrupted treatment course. This study was performed to evaluate the potential advantage of using passive-scattering (PS) and modulated-scanning (MS) proton therapy (PT) to reduce normal tissue exposure in postoperative pancreatic cancer treatment. A total of 11 patients with postoperative pancreatic cancer who had been previously treated with PS PT in University of Pennsylvania Roberts Proton Therapy Center from 2010 to 2013 were identified. The clinical target volume (CTV) includes the pancreatic tumor bed as well as the adjacent high-risk nodal areas. Internal (iCTV) was generated from 4-dimensional (4D) computed tomography (CT), taking into account target motion from breathing cycle. Three-field and 4-field 3D conformal radiation therapy (3DCRT), 5-field intensity-modulated radiation therapy, 2-arc volumetric-modulated radiation therapy, and 2-field PS and MS PT were created on the patients’ average CT. All the plans delivered 50.4 Gy to the planning target volume (PTV). Overall, 98% of PTV was covered by 95% of the prescription dose and 99% of iCTV received 98% prescription dose. The results show that all the proton plans offer significant lower doses to the left kidney (mean and V 18 Gy ), stomach (mean and V 20 Gy ), and cord (maximum dose) compared with all the photon plans, except 3-field 3DCRT in cord maximum dose. In addition, MS PT also provides lower doses to the right kidney (mean and V 18 Gy ), liver (mean dose), total bowel (V 20 Gy and mean dose), and small bowel (V 15 Gy absolute volume ratio) compared with all the photon plans and PS PT. The dosimetric advantage of PT points to the possibility of treating tumor bed and comprehensive nodal areas while providing a more tolerable treatment course that could be used for dose escalation and combining with radiosensitizing

  10. Infinite additional symmetries in two-dimensional conformal quantum field theory

    International Nuclear Information System (INIS)

    Zamolodchikov, A.B.

    1986-01-01

    This paper investigates additional symmetries in two-dimensional conformal field theory generated by spin s = 1/2, 1,...,3 currents. For spins s = 5/2 and s = 3, the generators of the symmetry form associative algebras with quadratic determining relations. ''Minimal models'' of conforma field theory with such additional symmetries are considered. The space of local fields occurring in a conformal field theory with additional symmetry corresponds to a certain (in general, reducible) representation of the corresponding algebra of the symmetry

  11. 3-D conformal radiation therapy - Part I: Treatment planning

    International Nuclear Information System (INIS)

    Burman, Chandra M.; Mageras, Gikas S.

    1997-01-01

    Objective: In this presentation we will look into the basic components of 3-dimensional conformal treatment planning, and will discuss planning for some selected sites. We will also review some current and future trends in 3-D treatment planning. External beam radiation therapy is one of the arms of cancer treatment. In the recent years 3-D conformal therapy had significant impact on the practice of external beam radiation therapy. Conformal radiation therapy shapes the high-dose volume so as to conform to the target volume while minimizing the dose to the surrounding normal tissues. The advances that have been achieved in conformal therapy are in part due to the development of 3-D treatment planning, which in turn has capitalized on 3-D imaging for tumor and normal tissue localization, as well as on available computational power for the calculation of 3-D dose distributions, visualization of anatomical and dose volumes, and numerical evaluation of treatment plans. In this course we will give an overview of how 3-D conformal treatments are designed and transferred to the patient. Topics will include: 1) description of the major components of a 3-D treatment planning system, 2) techniques for designing treatments, 3) evaluation of treatment plans using dose distribution displays, dose-volume histograms and normal tissue complication probabilities, 4) implementation of treatments using shaped blocks and multileaf collimators, 5) verification of treatment delivery using portal films and electronic portal imaging devices. We will also discuss some current and future trends in 3-D treatment planning, such as field shaping with multileaf collimation, computerized treatment plan optimization, including the use of nonuniform beam profiles (intensity modulation), and incorporating treatment uncertainties due to patient positioning errors and organ motion into treatment planning process

  12. Experimental investigation of an actively controlled three-dimensional turret wake

    Science.gov (United States)

    Shea, Patrick R.

    Hemispherical turrets are bluff bodies commonly used to house optical systems on airborne platforms. These bluff bodies develop complex, three-dimensional flow fields that introduce high mean and fluctuating loads to the turret as well as the airframe support structure which reduce the performance of both the optical systems and the aircraft. An experimental investigation of the wake of a three-dimensional, non-conformal turret was performed in a low-speed wind tunnel at Syracuse University to develop a better understanding of the fundamental flow physics associated with the turret wake. The flow field was studied at a diameter based Reynolds number of 550,000 using stereoscopic particle image velocimetry and dynamic pressure measurements both with and without active flow control. Pressure measurements were simultaneously sampled with the PIV measurements and taken on the surrounding boundary layer plate and at several locations on the turret geometry. Active flow control of the turret wake was performed around the leading edge of the turret aperture using dynamic suction in steady open-loop, unsteady open-loop, and simple closed-loop configurations. Analysis of the uncontrolled wake provided insight into the complex three-dimensional wake when evaluated spatially using PIV measurements and temporally using spectral analysis of the pressure measurements. Steady open-loop suction was found to significantly alter the spatial and temporal nature of the turret wake despite the control being applied locally to the aperture region of the turret. Unsteady open-loop and simple closed-loop control were found to provide similar levels of control to the steady open-loop forcing with a 45% reduction in the control input as calculated using the jet momentum coefficient. The data set collected provides unique information regarding the development of the baseline three-dimensional wake and the wake with three different active flow control configurations. These data can be used to

  13. Impact of Bone Marrow Radiation Dose on Acute Hematologic Toxicity in Cervical Cancer: Principal Component Analysis on High Dimensional Data

    International Nuclear Information System (INIS)

    Yun Liang; Messer, Karen; Rose, Brent S.; Lewis, John H.; Jiang, Steve B.; Yashar, Catheryn M.; Mundt, Arno J.; Mell, Loren K.

    2010-01-01

    Purpose: To study the effects of increasing pelvic bone marrow (BM) radiation dose on acute hematologic toxicity in patients undergoing chemoradiotherapy, using a novel modeling approach to preserve the local spatial dose information. Methods and Materials: The study included 37 cervical cancer patients treated with concurrent weekly cisplatin and pelvic radiation therapy. The white blood cell count nadir during treatment was used as the indicator for acute hematologic toxicity. Pelvic BM radiation dose distributions were standardized across patients by registering the pelvic BM volumes to a common template, followed by dose remapping using deformable image registration, resulting in a dose array. Principal component (PC) analysis was applied to the dose array, and the significant eigenvectors were identified by linear regression on the PCs. The coefficients for PC regression and significant eigenvectors were represented in three dimensions to identify critical BM subregions where dose accumulation is associated with hematologic toxicity. Results: We identified five PCs associated with acute hematologic toxicity. PC analysis regression modeling explained a high proportion of the variation in acute hematologicity (adjusted R 2 , 0.49). Three-dimensional rendering of a linear combination of the significant eigenvectors revealed patterns consistent with anatomical distributions of hematopoietically active BM. Conclusions: We have developed a novel approach that preserves spatial dose information to model effects of radiation dose on toxicity, which may be useful in optimizing radiation techniques to avoid critical subregions of normal tissues. Further validation of this approach in a large cohort is ongoing.

  14. Controllable load sharing for soft adhesive interfaces on three-dimensional surfaces

    Science.gov (United States)

    Song, Sukho; Drotlef, Dirk-Michael; Majidi, Carmel; Sitti, Metin

    2017-05-01

    For adhering to three-dimensional (3D) surfaces or objects, current adhesion systems are limited by a fundamental trade-off between 3D surface conformability and high adhesion strength. This limitation arises from the need for a soft, mechanically compliant interface, which enables conformability to nonflat and irregularly shaped surfaces but significantly reduces the interfacial fracture strength. In this work, we overcome this trade-off with an adhesion-based soft-gripping system that exhibits enhanced fracture strength without sacrificing conformability to nonplanar 3D surfaces. Composed of a gecko-inspired elastomeric microfibrillar adhesive membrane supported by a pressure-controlled deformable gripper body, the proposed soft-gripping system controls the bonding strength by changing its internal pressure and exploiting the mechanics of interfacial equal load sharing. The soft adhesion system can use up to ˜26% of the maximum adhesion of the fibrillar membrane, which is 14× higher than the adhering membrane without load sharing. Our proposed load-sharing method suggests a paradigm for soft adhesion-based gripping and transfer-printing systems that achieves area scaling similar to that of a natural gecko footpad.

  15. Dose volume assessment of high dose rate 192IR endobronchial implants

    International Nuclear Information System (INIS)

    Cheng, B. Saw; Korb, Leroy J.; Pawlicki, Todd; Wu, Andrew

    1996-01-01

    Purpose: To study the dose distributions of high dose rate (HDR) endobronchial implants using the dose nonuniformity ratio (DNR) and three volumetric irradiation indices. Methods and Materials: Multiple implants were configured by allowing a single HDR 192 Ir source to step through a length of 6 cm along an endobronchial catheter. Dwell times were computed to deliver a dose of 5 Gy to points 1 cm away from the catheter axis. Five sets of source configurations, each with different dwell position spacings from 0.5 to 3.0 cm, were evaluated. Three-dimensional (3D) dose distributions were then generated for each source configuration. Differential and cumulative dose-volume curves were generated to quantify the degree of target volume coverage, dose nonuniformity within the target volume, and irradiation of tissues outside the target volume. Evaluation of the implants were made using the DNR and three volumetric irradiation indices. Results: The observed isodose distributions were not able to satisfy all the dose constraints. The ability to optimally satisfy the dose constraints depended on the choice of dwell position spacing and the specification of the dose constraint points. The DNR and irradiation indices suggest that small dwell position spacing does not result in a more homogeneous dose distribution for the implant. This study supports the existence of a relationship between the dwell position spacing and the distance from the catheter axis to the reference dose or dose constraint points. Better dose homogeneity for an implant can be obtained if the spacing of the dwell positions are about twice the distance from the catheter axis to the reference dose or dose constraint points

  16. Three dimensional intensity modulated brachytherapy (IMBT): Dosimetry algorithm and inverse treatment planning

    International Nuclear Information System (INIS)

    Shi Chengyu; Guo Bingqi; Cheng, Chih-Yao; Esquivel, Carlos; Eng, Tony; Papanikolaou, Niko

    2010-01-01

    Purpose: The feasibility of intensity modulated brachytherapy (IMBT) to improve dose conformity for irregularly shaped targets has been previously investigated by researchers by means of using partially shielded sources. However, partial shielding does not fully explore the potential of IMBT. The goal of this study is to introduce the concept of three dimensional (3D) intensity modulated brachytherapy and solve two fundamental issues regarding the application of 3D IMBT treatment planning: The dose calculation algorithm and the inverse treatment planning method. Methods: A 3D IMBT treatment planning system prototype was developed using the MATLAB platform. This system consists of three major components: (1) A comprehensive IMBT source calibration method with dosimetric inputs from Monte Carlo (EGSnrc) simulations; (2) a ''modified TG-43'' (mTG-43) dose calculation formalism for IMBT dosimetry; and (3) a physical constraint based inverse IMBT treatment planning platform utilizing a simulated annealing optimization algorithm. The model S700 Axxent electronic brachytherapy source developed by Xoft, Inc. (Fremont, CA), was simulated in this application. Ten intracavitary accelerated partial breast irradiation (APBI) cases were studied. For each case, an ''isotropic plan'' with only optimized source dwell time and a fully optimized IMBT plan were generated and compared to the original plan in various dosimetric aspects, such as the plan quality, planning, and delivery time. The issue of the mechanical complexity of the IMBT applicator is not addressed in this study. Results: IMBT approaches showed superior plan quality compared to the original plans and the isotropic plans to different extents in all studied cases. An extremely difficult case with a small breast and a small distance to the ribs and skin, the IMBT plan minimized the high dose volume V 200 by 16.1% and 4.8%, respectively, compared to the original and the isotropic plans. The conformity index for the

  17. Three dimensional intensity modulated brachytherapy (IMBT): Dosimetry algorithm and inverse treatment planning

    Energy Technology Data Exchange (ETDEWEB)

    Shi Chengyu; Guo Bingqi; Cheng, Chih-Yao; Esquivel, Carlos; Eng, Tony; Papanikolaou, Niko [Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States); Department of Radiation Oncology, Oklahoma University Health Science Center, Oklahoma City, Oklahoma 73104 (United States); Cancer Therapy and Research Center, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States)

    2010-07-15

    Purpose: The feasibility of intensity modulated brachytherapy (IMBT) to improve dose conformity for irregularly shaped targets has been previously investigated by researchers by means of using partially shielded sources. However, partial shielding does not fully explore the potential of IMBT. The goal of this study is to introduce the concept of three dimensional (3D) intensity modulated brachytherapy and solve two fundamental issues regarding the application of 3D IMBT treatment planning: The dose calculation algorithm and the inverse treatment planning method. Methods: A 3D IMBT treatment planning system prototype was developed using the MATLAB platform. This system consists of three major components: (1) A comprehensive IMBT source calibration method with dosimetric inputs from Monte Carlo (EGSnrc) simulations; (2) a ''modified TG-43'' (mTG-43) dose calculation formalism for IMBT dosimetry; and (3) a physical constraint based inverse IMBT treatment planning platform utilizing a simulated annealing optimization algorithm. The model S700 Axxent electronic brachytherapy source developed by Xoft, Inc. (Fremont, CA), was simulated in this application. Ten intracavitary accelerated partial breast irradiation (APBI) cases were studied. For each case, an ''isotropic plan'' with only optimized source dwell time and a fully optimized IMBT plan were generated and compared to the original plan in various dosimetric aspects, such as the plan quality, planning, and delivery time. The issue of the mechanical complexity of the IMBT applicator is not addressed in this study. Results: IMBT approaches showed superior plan quality compared to the original plans and the isotropic plans to different extents in all studied cases. An extremely difficult case with a small breast and a small distance to the ribs and skin, the IMBT plan minimized the high dose volume V{sub 200} by 16.1% and 4.8%, respectively, compared to the original and the

  18. Three dimensional intensity modulated brachytherapy (IMBT): dosimetry algorithm and inverse treatment planning.

    Science.gov (United States)

    Shi, Chengyu; Guo, Bingqi; Cheng, Chih-Yao; Esquivel, Carlos; Eng, Tony; Papanikolaou, Niko

    2010-07-01

    The feasibility of intensity modulated brachytherapy (IMBT) to improve dose conformity for irregularly shaped targets has been previously investigated by researchers by means of using partially shielded sources. However, partial shielding does not fully explore the potential of IMBT. The goal of this study is to introduce the concept of three dimensional (3D) intensity modulated brachytherapy and solve two fundamental issues regarding the application of 3D IMBT treatment planning: The dose calculation algorithm and the inverse treatment planning method. A 3D IMBT treatment planning system prototype was developed using the MATLAB platform. This system consists of three major components: (1) A comprehensive IMBT source calibration method with dosimetric inputs from Monte Carlo (EGSnrc) simulations; (2) a "modified TG-43" (mTG-43) dose calculation formalism for IMBT dosimetry; and (3) a physical constraint based inverse IMBT treatment planning platform utilizing a simulated annealing optimization algorithm. The model S700 Axxent electronic brachytherapy source developed by Xoft, Inc. (Fremont, CA), was simulated in this application. Ten intracavitary accelerated partial breast irradiation (APBI) cases were studied. For each case, an "isotropic plan" with only optimized source dwell time and a fully optimized IMBT plan were generated and compared to the original plan in various dosimetric aspects, such as the plan quality, planning, and delivery time. The issue of the mechanical complexity of the IMBT applicator is not addressed in this study. IMBT approaches showed superior plan quality compared to the original plans and tht isotropic plans to different extents in all studied cases. An extremely difficult case with a small breast and a small distance to the ribs and skin, the IMBT plan minimized the high dose volume V200 by 16.1% and 4.8%, respectively, compared to the original and the isotropic plans. The conformity index for the target was increased by 0.13 and 0

  19. Advanced prostate cancer: the results of a randomized comparative trial of high dose irradiation boosting with conformal protons compared with conventional dose irradiation using photons alone

    Energy Technology Data Exchange (ETDEWEB)

    Shipley, William U; Verhey, Lynn J; Munzenrider, John E; Suit, Herman D; Urie, Marcia M; McManus, Patricia L; Young, Robert H; Shipley, Jenot W; Zietman, Anthony L; Biggs, Peter J; Heney, Niall M; Goitein, Michael

    1995-04-30

    Purpose: Following a thorough Phase I/II study, we evaluated by a Phase III trial high versus conventional dose external beam irradiation as mono-therapy for patients with Stage T3-T4 prostate cancer. Patient outcome following standard dose radiotherapy or following a 12.5% increase in total dose to 75.6 Cobalt Gray Equivalent (CGE) using a conformal perineal proton boost was compared for local tumor control, disease-free survival, and overall survival. Methods and Materials: Stage T3-T4, Nx, N0-2, M0 patients received 50.4 Gy by four-field photons and were randomized to receive either an additional 25.2 CGE by conformal protons (arm 1--the high dose arm, 103 patients, total dose 75.6 CGE) or an additional 16.8 Gy by photons (arm 2--the conventional dose arm, 99 patients, total dose 67.2 Gy). Actuarial overall survival (OS), disease-specific survival (DSS), total recurrence-free survival (TRFS), (clinically free, prostate specific antigen (PSA) less than 4ng/ml and a negative prostate rebiopsy, done in 38 patients without evidence of disease) and local control (digital rectal exam and rebiopsy negative) were evaluated. Results: The protocol completion rate was 90% for arm 1 and 97% for arm 2. With a median follow-up of 61 months (range 3 to 139 months) 135 patients are alive and 67 have died, 20 from causes other than prostate cancer. We found no significant differences in OS, DSS, TRFS or local control between the two arms. Among those completing randomized treatment (93 in arm 1 and 96 in arm 2), the local control at 5 and 8 years for arm 1 is 92% and 77%, respectively and is 80% and 60%, respectively for arm 2 (p = .089) and there are no significant differences in OS, DSS, and TRFS. The local control for the 57 patients with poorly differentiated (Gleason 4 or 5 of 5) tumors at 5 and 8 years for arm 1 is 94% and 84% and is 64% and 19% on arm 2 (p 0.0014). In patients whose digital rectal exam had normalized following treatment and underwent prostate rebiopsy

  20. Advanced prostate cancer: the results of a randomized comparative trial of high dose irradiation boosting with conformal protons compared with conventional dose irradiation using photons alone

    International Nuclear Information System (INIS)

    Shipley, William U.; Verhey, Lynn J.; Munzenrider, John E.; Suit, Herman D.; Urie, Marcia M.; McManus, Patricia L.; Young, Robert H.; Shipley, Jenot W.; Zietman, Anthony L.; Biggs, Peter J.; Heney, Niall M.; Goitein, Michael

    1995-01-01

    Purpose: Following a thorough Phase I/II study, we evaluated by a Phase III trial high versus conventional dose external beam irradiation as mono-therapy for patients with Stage T3-T4 prostate cancer. Patient outcome following standard dose radiotherapy or following a 12.5% increase in total dose to 75.6 Cobalt Gray Equivalent (CGE) using a conformal perineal proton boost was compared for local tumor control, disease-free survival, and overall survival. Methods and Materials: Stage T3-T4, Nx, N0-2, M0 patients received 50.4 Gy by four-field photons and were randomized to receive either an additional 25.2 CGE by conformal protons (arm 1--the high dose arm, 103 patients, total dose 75.6 CGE) or an additional 16.8 Gy by photons (arm 2--the conventional dose arm, 99 patients, total dose 67.2 Gy). Actuarial overall survival (OS), disease-specific survival (DSS), total recurrence-free survival (TRFS), (clinically free, prostate specific antigen (PSA) less than 4ng/ml and a negative prostate rebiopsy, done in 38 patients without evidence of disease) and local control (digital rectal exam and rebiopsy negative) were evaluated. Results: The protocol completion rate was 90% for arm 1 and 97% for arm 2. With a median follow-up of 61 months (range 3 to 139 months) 135 patients are alive and 67 have died, 20 from causes other than prostate cancer. We found no significant differences in OS, DSS, TRFS or local control between the two arms. Among those completing randomized treatment (93 in arm 1 and 96 in arm 2), the local control at 5 and 8 years for arm 1 is 92% and 77%, respectively and is 80% and 60%, respectively for arm 2 (p = .089) and there are no significant differences in OS, DSS, and TRFS. The local control for the 57 patients with poorly differentiated (Gleason 4 or 5 of 5) tumors at 5 and 8 years for arm 1 is 94% and 84% and is 64% and 19% on arm 2 (p 0.0014). In patients whose digital rectal exam had normalized following treatment and underwent prostate rebiopsy

  1. Biomedical applications of two- and three-dimensional deterministic radiation transport methods

    International Nuclear Information System (INIS)

    Nigg, D.W.

    1992-01-01

    Multidimensional deterministic radiation transport methods are routinely used in support of the Boron Neutron Capture Therapy (BNCT) Program at the Idaho National Engineering Laboratory (INEL). Typical applications of two-dimensional discrete-ordinates methods include neutron filter design, as well as phantom dosimetry. The epithermal-neutron filter for BNCT that is currently available at the Brookhaven Medical Research Reactor (BMRR) was designed using such methods. Good agreement between calculated and measured neutron fluxes was observed for this filter. Three-dimensional discrete-ordinates calculations are used routinely for dose-distribution calculations in three-dimensional phantoms placed in the BMRR beam, as well as for treatment planning verification for live canine subjects. Again, good agreement between calculated and measured neutron fluxes and dose levels is obtained

  2. The field-matching problem as it applies to the peacock three dimensional conformal system for intensity modulation

    International Nuclear Information System (INIS)

    Carol, Mark; Grant, Walter H.; Bleier, Alan R.; Kania, Alex A.; Targovnik, Harris S.; Butler, E. Brian; Shiao, W. Woo

    1996-01-01

    Purpose: Intensity modulated beam systems have been developed as a means of creating a high-dose region that closely conforms to the prescribed target volume while also providing specific sparing of organs at risk within complex treatment geometries. The slice-by-slice treatment paradigm used by one such system for delivering intensity modulated fields introduces regions of dose nonuniformity where each pair of treatment slices abut. A study was designed to evaluate whether or not the magnitude of the nonuniformity that results from this segmental delivery paradigm is significant relative to the overall dose nonuniformity present in the intensity modulation technique itself. An assessment was also made as to the increase in nonuniformity that would result if errors were made in indexing during treatment delivery. Methods and Materials: Treatment plans were generated to simulate correctly indexed and incorrectly indexed treatments of 4, 10, and 18 cm diameter targets. Indexing errors of from 0.1 to 2.0 mm were studied. Treatment plans were also generated for targets of the same diameter but of lengths that did not require indexing of the treatment couch. Results: The nonuniformity that results from the intensity modulation delivery paradigm is 11-16% for targets where indexing is not required. Correct indexing of the couch adds an additional 1-2% in nonuniformity. However, a couch indexing error of as little as 1 mm can increase the total nonuniformity to as much as 25%. All increases in nonuniformity from indexing are essentially independent of target diameter. Conclusions: The dose nonuniformity introduced by the segmental strip delivery paradigm is small relative to the nonuniformity present in the intensity modulation paradigm itself. A positioning accuracy of better than 0.5 mm appears to be required when implementing segmental intensity modulated treatment plans

  3. Phase II clinical trial of whole-brain irradiation plus three-dimensional conformal boost with concurrent topotecan for brain metastases from lung cancer

    International Nuclear Information System (INIS)

    Ge, Xiao-hui; Liu, Miao-ling; Lin, Qiang; Ren, Xiao-cang; Liu, Yue-e; Chen, Xue-ji; Wang, Dong-ying; Wang, Yong-qiang; Cao, Bin; Li, Zhi-gang

    2013-01-01

    Patients with brain metastases from lung cancer have poor prognoses and short survival time, and they are often excluded from clinical trials. Whole-cranial irradiation is considered to be the standard treatment, but its efficacy is not satisfactory. The purpose of this phase II clinical trial was to evaluate the preliminary efficacy and safety of the treatment of whole-brain irradiation plus three-dimensional conformal boost combined with concurrent topotecan for the patients with brain metastases from lung cancer. Patients with brain metastasis from lung cancer received concurrent chemotherapy and radiotherapy: conventional fractionated whole-brain irradiation, 2 fields/time, 1 fraction/day, 2 Gy/fraction, 5 times/week, and DT 40 Gy/20 fractions; for the patients with ≤ 3 lesions with diameter ≥ 2 cm, a three-dimensional (3-D) conformal localised boost was given to increase the dosage to 56–60 Gy; and during radiotherapy, concurrent chemotherapy with topotecan was given (the chemoradiotherapy group, CRT). The patients with brain metastasis from lung cancer during the same period who received radiotherapy only were selected as the controls (the radiotherapy-alone group, RT). From March 2009 to March 2012, both 38 patients were enrolled into two groups. The median progression-free survival(PFS) time , the 1- and 2-year PFS rates of CRT group and RT group were 6 months, 42.8%, 21.6% and 3 months, 11.6%, 8.7% (χ 2 = 6.02, p = 0.014), respectively. The 1- and 2-year intracranial lesion control rates of CRT and RT were 75.9% , 65.2% and 41.6% , 31.2% (χ 2 = 3.892, p = 0.049), respectively. The 1- and 2-year overall survival rates (OS) of CRT and RT were 50.8% , 37.9% and 40.4% , 16.5% (χ 2 = 1.811, p = 0.178), respectively. The major side effects were myelosuppression and digestive toxicities, but no differences were observed between the two groups. Compared with radiotherapy alone, whole-brain irradiation plus 3-D conformal boost irradiation and concurrent

  4. High-dose Extended-Field Irradiation and High-Dose-Rate Brachytherapy With Concurrent Chemotherapy for Cervical Cancer With Positive Para-Aortic Lymph Nodes

    International Nuclear Information System (INIS)

    Kim, Young Seok; Kim, Jong Hoon; Ahn, Seung Do; Lee, Sang-wook; Shin, Seong Soo; Nam, Joo-Hyun; Kim, Young-Tak; Kim, Yong-Man; Kim, Jong-Hyeok; Choi, Eun Kyung

    2009-01-01

    Purpose: To determine the efficacy and toxicity of extended-field radiotherapy (RT) with concurrent platinum-based chemotherapy in patients with uterine cervical carcinoma and positive para-aortic nodes. Methods and Materials: We retrospectively reviewed the results for 33 women with Stage IB-IVB cervical cancer. Each patient had received 59.4 Gy, including a three-dimensional conformal boost to the para-aortic lymph nodes and 41.4-50.4 Gy of external beam radiotherapy to the pelvis. Each patient also underwent six or seven applications of high-dose-rate brachytherapy (median, 5 Gy to point A at each session). Results: The median follow-up period of surviving patients was 39 months. The most common acute toxicity was hematologic, observed in 23 women. Severe acute and late gastrointestinal toxicity was observed in 3 and 4 patients, respectively. More than three-quarters of patients showed a complete response, encompassing the primary mass, metastatic pelvic, and para-aortic lymph nodes. Of the 33 women, 15 had no evidence of disease, 6 had persistent disease, 4 developed in-field failures, and 6 developed distant failures. The 5-year overall and disease-free survival rate was 47% and 42%, respectively. Conclusion: Concurrent chemoradiotherapy with extended-field radiotherapy is feasible in women with uterine cervical carcinoma and positive para-aortic lymph nodes, with acceptable late morbidity and a high survival rate, although it was accompanied by substantial acute toxicity.

  5. Potential for Improved Intelligence Quotient Using Volumetric Modulated Arc Therapy Compared With Conventional 3-Dimensional Conformal Radiation for Whole-Ventricular Radiation in Children

    International Nuclear Information System (INIS)

    Qi, X. Sharon; Stinauer, Michelle; Rogers, Brion; Madden, Jennifer R.; Wilkening, Greta N.; Liu, Arthur K.

    2012-01-01

    Purpose: To compare volumetric modulated arc therapy (VMAT) with 3-dimensional conformal radiation therapy (3D-CRT) in the treatment of localized intracranial germinoma. We modeled the effect of the dosimetric differences on intelligence quotient (IQ). Method and Materials: Ten children with intracranial germinomas were used for planning. The prescription doses were 23.4 Gy to the ventricles followed by 21.6 Gy to the tumor located in the pineal region. For each child, a 3D-CRT and full arc VMAT was generated. Coverage of the target was assessed by computing a conformity index and heterogeneity index. We also generated VMAT plans with explicit temporal lobe sparing and with smaller ventricular margin expansions. Mean dose to the temporal lobe was used to estimate IQ 5 years after completion of radiation, using a patient age of 10 years. Results: Compared with the 3D-CRT plan, VMAT improved conformality (conformity index 1.10 vs 1.85), with slightly higher heterogeneity (heterogeneity index 1.09 vs 1.06). The averaged mean doses for left and right temporal lobes were 31.3 and 31.7 Gy, respectively, for VMAT plans and 37.7 and 37.6 Gy for 3D-CRT plans. This difference in mean temporal lobe dose resulted in an estimated IQ difference of 3.1 points at 5 years after radiation therapy. When the temporal lobes were explicitly included in the VMAT optimization, the mean temporal lobe dose was reduced 5.6-5.7 Gy, resulting in an estimated IQ difference of an additional 3 points. Reducing the ventricular margin from 1.5 cm to 0.5 cm decreased mean temporal lobe dose 11.4-13.1 Gy, corresponding to an estimated increase in IQ of 7 points. Conclusion: For treatment of children with intracranial pure germinomas, VMAT compared with 3D-CRT provides increased conformality and reduces doses to normal tissue. This may result in improvements in IQ in these children.

  6. Three-dimensional viewing and dosimetric calculations of Au-198 implants of the prostate

    International Nuclear Information System (INIS)

    Avizonis, V.N.; Anderson, K.M.; Jani, S.K.; Hussey, D.H.

    1991-01-01

    Dose gradients for brachytherapy vary considerably in three dimensions, which complicates conventional two-dimensional dosimetry. Recent developments in computer graphics technology have enabled visualization of anatomy and radiation doses in three dimensions. The objective of this paper is to develop a three-dimensional viewing and dosimetry program for brachytherapy and to test this system in phantoms and in patients undergoing Au-198 implants in the prostate. Three-dimensional computer algorithms for the author's Silicon Graphics supercomputing workstation were developed, tested, and modified on the basis of studies in phantoms and patients. Studies were performed on phantoms of known dimensions and gold seeds in known locations to assess the accuracy of volume reconstruction, seed placement, and isodose distribution. Isodose curves generated with the three-dimensional system were compared with those generated by a Theratronics Treatment Planning Computer using conventional methods. Twenty patients with permanent Au-198 interstitial implants in the prostate were similarly studied

  7. Three-dimensional portal image-based dose reconstruction in a virtual phantom for rapid evaluation of IMRT plans

    International Nuclear Information System (INIS)

    Ansbacher, W.

    2006-01-01

    A new method for rapid evaluation of intensity modulated radiation therapy (IMRT) plans has been developed, using portal images for reconstruction of the dose delivered to a virtual three-dimensional (3D) phantom. This technique can replace an array of less complete but more time-consuming measurements. A reference dose calculation is first created by transferring an IMRT plan to a cylindrical phantom, retaining the treatment gantry angles. The isocenter of the fields is placed on or near the phantom axis. This geometry preserves the relative locations of high and low dose regions and has the required symmetry for the dose reconstruction. An electronic portal image (EPI) is acquired for each field, representing the dose in the midplane of a virtual phantom. The image is convolved with a kernel to correct for the lack of scatter, replicating the effect of the cylindrical phantom surrounding the dose plane. This avoids the need to calculate fluence. Images are calibrated to a reference field that delivers a known dose to the isocenter of this phantom. The 3D dose matrix is reconstructed by attenuation and divergence corrections and summed to create a dose matrix (PI-dose) on the same grid spacing as the reference calculation. Comparison of the two distributions is performed with a gradient-weighted 3D dose difference based on dose and position tolerances. Because of its inherent simplicity, the technique is optimally suited for detecting clinically significant variances from a planned dose distribution, rather than for use in the validation of IMRT algorithms. An analysis of differences between PI-dose and calculation, δ PI , compared to differences between conventional quality assurance (QA) and calculation, δ CQ , was performed retrospectively for 20 clinical IMRT cases. PI-dose differences at the isocenter were in good agreement with ionization chamber differences (mean δ PI =-0.8%, standard deviation σ=1.5%, against δ CQ =0.3%, σ=1.0%, respectively). PI-dose

  8. Numerical estimation of structure constants in the three-dimensional Ising conformal field theory through Markov chain uv sampler

    Science.gov (United States)

    Herdeiro, Victor

    2017-09-01

    Herdeiro and Doyon [Phys. Rev. E 94, 043322 (2016), 10.1103/PhysRevE.94.043322] introduced a numerical recipe, dubbed uv sampler, offering precise estimations of the conformal field theory (CFT) data of the planar two-dimensional (2D) critical Ising model. It made use of scale invariance emerging at the critical point in order to sample finite sublattice marginals of the infinite plane Gibbs measure of the model by producing holographic boundary distributions. The main ingredient of the Markov chain Monte Carlo sampler is the invariance under dilation. This paper presents a generalization to higher dimensions with the critical 3D Ising model. This leads to numerical estimations of a subset of the CFT data—scaling weights and structure constants—through fitting of measured correlation functions. The results are shown to agree with the recent most precise estimations from numerical bootstrap methods [Kos, Poland, Simmons-Duffin, and Vichi, J. High Energy Phys. 08 (2016) 036, 10.1007/JHEP08(2016)036].

  9. [Extraction of buildings three-dimensional information from high-resolution satellite imagery based on Barista software].

    Science.gov (United States)

    Zhang, Pei-feng; Hu, Yuan-man; He, Hong-shi

    2010-05-01

    The demand for accurate and up-to-date spatial information of urban buildings is becoming more and more important for urban planning, environmental protection, and other vocations. Today's commercial high-resolution satellite imagery offers the potential to extract the three-dimensional information of urban buildings. This paper extracted the three-dimensional information of urban buildings from QuickBird imagery, and validated the precision of the extraction based on Barista software. It was shown that the extraction of three-dimensional information of the buildings from high-resolution satellite imagery based on Barista software had the advantages of low professional level demand, powerful universality, simple operation, and high precision. One pixel level of point positioning and height determination accuracy could be achieved if the digital elevation model (DEM) and sensor orientation model had higher precision and the off-Nadir View Angle was relatively perfect.

  10. In vivo dosimetry: measurement of entrance and exit dose using MOSFET dosimeter

    International Nuclear Information System (INIS)

    Gopiraj, A.; Billimagga, Ramesh S.; Rekha, M.; Ramasubramaniam, V.

    2007-01-01

    Patient dose verification is an essential part of a Quality Assurance (QA) program in a Radiotherapy Department. As the transition is made from the conventional two-dimensional (2D) to three-dimensional (3D) conformal and intensity modulated therapy, it is recommended that new treatment techniques be checked systematically to guarantee accurate dose delivery by means of a comprehensive in vivo dosimetry program (i.e. real-time dosimetry during patient treatment). The authors conducted a study to assess the clinical utility of in vivo dosimetry in the Dept. of Radiation Oncology using MOSFET dosimetry system

  11. An interactive beam-weight optimization tool for three-dimensional radiotherapy treatment planning

    International Nuclear Information System (INIS)

    Burba, S.; Gardey, K.; Nadobny, J.; Stalling, D.; Seebass, M.; Beier, J.; Wust, P.; Budach, V.; Felix, R.

    1997-01-01

    that the beam configuration is inappropriate. Possible reasons for this may be that part of the target volume may have been missed by one or more beams, or there may have been excessive beam overlap. The beam-weight optimization tool can then be used to warn the treatment planner of this occurrence, thus avoiding excessive planner time in attempting to find an acceptable solution. In addition the possibilities of the three-dimensional representation of dose distribution offered by the high-performance visualization workstation could be combined with the first attempt at a feasibility search for enhancing the degree of interactive optimization of treatment planning. Conclusions: We have demonstrated how a beam-weight optimization tool can be incorporated into a treatment planning system offering plenty of visualization tools for realizing virtual therapy planning. Further software development is required with respect to the acceleration of calculation time, the implication of borderline cases and the inclusion of further biological and clinical relevant parameters according to the definition of further objective functions. The software tools developed up to now constitute the basis for the development of an alternative voxel oriented mathematical formulation of inverse treatment planning for optimizing conformation therapy

  12. Dose conformation to the spine during palliative treatments using dynamic wedges

    Energy Technology Data Exchange (ETDEWEB)

    Ormsby, Matthew A., E-mail: Matthew.Ormsby@usoncology.com [West Texas Cancer Center at Medical Center Hospital, Odessa, TX (United States); Herndon, R. Craig; Kaczor, Joseph G. [West Texas Cancer Center at Medical Center Hospital, Odessa, TX (United States)

    2013-07-01

    Radiation therapy is commonly used to alleviate pain associated with metastatic disease of the spine. Often, isodose lines are manipulated using dynamic or physical wedges to encompass the section of spine needing treatment while minimizing dose to normal tissue. We will compare 2 methods used to treat the entire thoracic spine. The first method treats the thoracic spine with a single, nonwedged posterior-anterior (PA) field. Dose is prescribed to include the entire spine. Isodose lines tightly conform to the top and bottom vertebrae, but vertebrae between these 2 received more than enough coverage. The second method uses a combination of wedges to create an isodose line that mimics the curvature of the thoracic spine. This “C”-shaped curvature is created by overlapping 2 fields with opposing dynamic wedges. Machine constraints limit the treatment length and therefore 2 isocenters are used. Each of the 2 PA fields contributes a portion of the total daily dose. This technique creates a “C”-shaped isodose line that tightly conforms to the thoracic spine, minimizing normal tissue dose. Spinal cord maximum dose is reduced, as well as mean dose to the liver, esophagus, and heart.

  13. Creating physically-based three-dimensional microstructures: Bridging phase-field and crystal plasticity models.

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Hojun [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Owen, Steven J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Abdeljawad, Fadi F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hanks, Byron [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Battaile, Corbett Chandler [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    In order to better incorporate microstructures in continuum scale models, we use a novel finite element (FE) meshing technique to generate three-dimensional polycrystalline aggregates from a phase field grain growth model of grain microstructures. The proposed meshing technique creates hexahedral FE meshes that capture smooth interfaces between adjacent grains. Three dimensional realizations of grain microstructures from the phase field model are used in crystal plasticity-finite element (CP-FE) simulations of polycrystalline a -iron. We show that the interface conformal meshes significantly reduce artificial stress localizations in voxelated meshes that exhibit the so-called "wedding cake" interfaces. This framework provides a direct link between two mesoscale models - phase field and crystal plasticity - and for the first time allows mechanics simulations of polycrystalline materials using three-dimensional hexahedral finite element meshes with realistic topological features.

  14. Non-conformal contact mechanical characteristic analysis on spherical components

    Energy Technology Data Exchange (ETDEWEB)

    Zhen-zhi, G.; Bin, H.; Zheng-ming, G.; Feng-mei, Y.; Jin, Q [The 2. Artillery Engineering Univ., Xi' an (China)

    2017-03-15

    Non-conformal spherical-contact mechanical problems is a three-dimensional coordination or similar to the coordination spherical contact. Due to the complexity of the problem of spherical-contact and difficulties of solving higher-order partial differential equations, problems of three-dimensional coordination or similar to the coordination spherical-contact is still no exact analytical method for solving. It is based on three-dimensional taper model is proposed a model based on the contour surface of the spherical contact and concluded of the formula of the contact pressure and constructed of finite element model by contact pressure distribution under the non-conformal spherical. The results shows spherical contact model can reflect non-conformal spherical-contacting mechanical problems more than taper-contacting model, and apply for the actual project.

  15. Couplings between hierarchical conformational dynamics from multi-time correlation functions and two-dimensional lifetime spectra: Application to adenylate kinase

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Junichi [Department of Theoretical and Computational Molecular Science, Institute for Molecular Science, Okazaki 444-8585 (Japan); Takada, Shoji [Department of Theoretical and Computational Molecular Science, Institute for Molecular Science, Okazaki 444-8585 (Japan); Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Saito, Shinji, E-mail: shinji@ims.ac.jp [Department of Theoretical and Computational Molecular Science, Institute for Molecular Science, Okazaki 444-8585 (Japan); The Graduate University for Advanced Studies, Okazaki 444-8585 (Japan)

    2015-06-07

    An analytical method based on a three-time correlation function and the corresponding two-dimensional (2D) lifetime spectrum is developed to elucidate the time-dependent couplings between the multi-timescale (i.e., hierarchical) conformational dynamics in heterogeneous systems such as proteins. In analogy with 2D NMR, IR, electronic, and fluorescence spectroscopies, the waiting-time dependence of the off-diagonal peaks in the 2D lifetime spectra can provide a quantitative description of the dynamical correlations between the conformational motions with different lifetimes. The present method is applied to intrinsic conformational changes of substrate-free adenylate kinase (AKE) using long-time coarse-grained molecular dynamics simulations. It is found that the hierarchical conformational dynamics arise from the intra-domain structural transitions among conformational substates of AKE by analyzing the one-time correlation functions and one-dimensional lifetime spectra for the donor-acceptor distances corresponding to single-molecule Förster resonance energy transfer experiments with the use of the principal component analysis. In addition, the complicated waiting-time dependence of the off-diagonal peaks in the 2D lifetime spectra for the donor-acceptor distances is attributed to the fact that the time evolution of the couplings between the conformational dynamics depends upon both the spatial and temporal characters of the system. The present method is expected to shed light on the biological relationship among the structure, dynamics, and function.

  16. Conventional (2D) Versus Conformal (3D) Techniques in Radiotherapy for Malignant Pediatric Tumors: Dosimetric Perspectives

    International Nuclear Information System (INIS)

    Ahmad, N.; Attia, G.; Radwan, A.; El-Badawy, S.; El-Ghoneimy, E.

    2009-01-01

    Objectives: In pediatric radiotherapy, the enhanced radiosensitivity of the developing tissues combined with the high overall survival, raise the possibility of late complications. The present study aims at comparing two dimensional (2D) and three dimensional (3D) planning regarding dose homogeneity within target volume and dose to organs at risk (OARs) to demonstrate the efficacy of 3D in decreasing dose to normal tissue. Material and Methods: Thirty pediatric patients (18 years or less) with different pediatric tumors were planned using 2D and 3D plans. All were CT scanned after proper positioning and immobilization. Structures were contoured; including the planning target volume (PTV) and organs at risk (OARs). Conformal beams were designed and dose distribution analysis was edited to provide the best dose coverage to the PTV while sparing OARs using dose volume histograms (DVHs) of outlined structures. For the same PTVs conventional plans were created using the conventional simulator data (2-4 coplanar fields). Conventional and 3D plans coverage and distribution were compared using the term of V95% (volume of PTV receiving 95% of the prescribed dose), V107% (volume of PTV receiving 107% of the prescribed dose), and conformity index (CI) (volume receiving 90% of the prescribed dose/PTV). Doses received by OARs were compared in terms of mean dose. In children treated for brain lesions, OAR volume received 90% of the dose (V 90%) and OAR score were calculated. Results: The PTV coverage showed no statistical difference between 2D and 3D radiotherapy in terms of V95% or V107%. However, there was more conformity in 3D planning with CI 1.43 rather than conventional planning with CI 1.86 (p-value <0.001). Regarding OARs, 3D planning shows large gain in healthy tissue sparing. There was no statistical difference in mean dose received by each OAR. However, for brain cases, brain stem mean dose and brain V 90% showed better sparing in 3D planning (brain stem mean dose was

  17. Braided structure in 4-dimensional conformal quantum field theory

    International Nuclear Information System (INIS)

    Schroer, Bert

    2001-03-01

    Higher dimensional conformal QFT possesses an intersting braided structure which different from the d=1+1 models, is restricted to the timelike region and therefore easily escapes euclidean action methods. It lies behind the spectrum of anamalous which may be viewed as a kind of substitute for a missing particle interpretation in the presence of interactions. (author)

  18. Two-dimensional versus three-dimensional treatment planning of tangential breast irradiation

    International Nuclear Information System (INIS)

    Damen, E.M.F.; Bruinvis, I.A.D.; Mijnheer, B.J.

    1995-01-01

    Purpose: Full three-dimensional (3-D) treatment planning requires 3-D patient contours and density information, derived either from CT scanning or from other 3-D contouring methods. These contouring techniques are time consuming, and are often not available or cannot be used. Two-dimensional (2-D) treatment planning can be performed using only a few patient contours, made with much simpler techniques, in combination with simulator images for estimating the lung position. In order to investigate the need for full 3-D planning, we compared the performance of both a 2-D and a 3-D planning system in calculating absolute dose values and relative dose distributions in tangential breast irradiation. Methods: Two breast-shaped phantoms were used in this study. The first phantom consists of a polyethylene mould, filled with water and cork to mimic the lung. An ionization chamber can be inserted in the phantom at fixed positions. The second phantom is made of 25 transverse slices of polystyrene and cork, made with a computerized milling machine from CT information. In this phantom, films can be inserted in three sagittal planes. Both phantoms have been irradiated with two tangential 8 MV photon beams. The measured dose distribution has been compared with the dose distribution predicted by the two planning systems. Results: In the central plane, the 3-D planning system predicts the absolute dose with an accuracy of 0.5 - 4%. The dose at the isocentre of the beams agrees within 0.5% with the measured dose. The 2-D system predicts the dose with an accuracy of 0.9 - 3%. The dose calculated at the isocentre is 2.6% higher than the measured dose, because missing lateral scatter is not taken into account in this planning system. In off-axis planes, the calculated absolute dose agrees with the measured dose within 4% for the 2-D system and within 6% for the 3-D system. However, the relative dose distribution is predicted better by the 3-D planning system. Conclusions: This study

  19. Knowledge-based prediction of three-dimensional dose distributions for external beam radiotherapy

    International Nuclear Information System (INIS)

    Shiraishi, Satomi; Moore, Kevin L.

    2016-01-01

    Purpose: To demonstrate knowledge-based 3D dose prediction for external beam radiotherapy. Methods: Using previously treated plans as training data, an artificial neural network (ANN) was trained to predict a dose matrix based on patient-specific geometric and planning parameters, such as the closest distance (r) to planning target volume (PTV) and organ-at-risks (OARs). Twenty-three prostate and 43 stereotactic radiosurgery/radiotherapy (SRS/SRT) cases with at least one nearby OAR were studied. All were planned with volumetric-modulated arc therapy to prescription doses of 81 Gy for prostate and 12–30 Gy for SRS. Using these clinically approved plans, ANNs were trained to predict dose matrix and the predictive accuracy was evaluated using the dose difference between the clinical plan and prediction, δD = D clin − D pred . The mean (〈δD r 〉), standard deviation (σ δD r ), and their interquartile range (IQR) for the training plans were evaluated at a 2–3 mm interval from the PTV boundary (r PTV ) to assess prediction bias and precision. Initially, unfiltered models which were trained using all plans in the cohorts were created for each treatment site. The models predict approximately the average quality of OAR sparing. Emphasizing a subset of plans that exhibited superior to the average OAR sparing during training, refined models were created to predict high-quality rectum sparing for prostate and brainstem sparing for SRS. Using the refined model, potentially suboptimal plans were identified where the model predicted further sparing of the OARs was achievable. Replans were performed to test if the OAR sparing could be improved as predicted by the model. Results: The refined models demonstrated highly accurate dose distribution prediction. For prostate cases, the average prediction bias for all voxels irrespective of organ delineation ranged from −1% to 0% with maximum IQR of 3% over r PTV ∈ [ − 6, 30] mm. The average prediction error was less

  20. SU-F-T-381: Fast Calculation of Three-Dimensional Dose Considering MLC Leaf Positional Errors for VMAT Plans

    Energy Technology Data Exchange (ETDEWEB)

    Katsuta, Y [Takeda General Hospital, Aizuwakamatsu City, Fukushima (Japan); Tohoku University Graduate School of Medicine, Sendal, Miyagi (Japan); Kadoya, N; Jingu, K [Tohoku University Graduate School of Medicine, Sendal, Miyagi (Japan); Shimizu, E; Majima, K [Takeda General Hospital, Aizuwakamatsu City, Fukushima (Japan)

    2016-06-15

    Purpose: In this study, we developed a system to calculate three dimensional (3D) dose that reflects dosimetric error caused by leaf miscalibration for head and neck and prostate volumetric modulated arc therapy (VMAT) without additional treatment planning system calculation on real time. Methods: An original system called clarkson dose calculation based dosimetric error calculation to calculate dosimetric error caused by leaf miscalibration was developed by MATLAB (Math Works, Natick, MA). Our program, first, calculates point doses at isocenter for baseline and modified VMAT plan, which generated by inducing MLC errors that enlarged aperture size of 1.0 mm with clarkson dose calculation. Second, error incuced 3D dose was generated with transforming TPS baseline 3D dose using calculated point doses. Results: Mean computing time was less than 5 seconds. For seven head and neck and prostate plans, between our method and TPS calculated error incuced 3D dose, the 3D gamma passing rates (0.5%/2 mm, global) are 97.6±0.6% and 98.0±0.4%. The dose percentage change with dose volume histogram parameter of mean dose on target volume were 0.1±0.5% and 0.4±0.3%, and with generalized equivalent uniform dose on target volume were −0.2±0.5% and 0.2±0.3%. Conclusion: The erroneous 3D dose calculated by our method is useful to check dosimetric error caused by leaf miscalibration before pre treatment patient QA dosimetry checks.

  1. Proton Radiotherapy for High-Risk Pediatric Neuroblastoma: Early Outcomes and Dose Comparison

    Energy Technology Data Exchange (ETDEWEB)

    Hattangadi, Jona A. [Harvard Radiation Oncology Program, Boston, MA (United States); Rombi, Barbara [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Provincial Agency for Proton Therapy, Trento (Italy); Yock, Torunn I.; Broussard, George [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Friedmann, Alison M.; Huang, Mary [Department of Pediatric Hematology-Oncology, Massachusetts General Hospital, Boston, MA (United States); Chen, Yen-Lin E.; Lu, Hsiao-Ming; Kooy, Hanne [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); MacDonald, Shannon M., E-mail: smacdonald@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States)

    2012-07-01

    Purpose: To report the early outcomes for children with high-risk neuroblastoma treated with proton radiotherapy (RT) and to compare the dose distributions for intensity-modulated photon RT (IMRT), three-dimensional conformal proton RT (3D-CPT), and intensity-modulated proton RT to the postoperative tumor bed. Methods and Materials: All patients with high-risk (International Neuroblastoma Staging System Stage III or IV) neuroblastoma treated between 2005 and 2010 at our institution were included. All patients received induction chemotherapy, surgical resection of residual disease, high-dose chemotherapy with stem cell rescue, and adjuvant 3D-CPT to the primary tumor sites. The patients were followed with clinical examinations, imaging, and laboratory testing every 6 months to monitor disease control and side effects. IMRT, 3D-CPT, and intensity-modulated proton RT plans were generated and compared for a representative case of adjuvant RT to the primary tumor bed followed by a boost. Results: Nine patients were treated with 3D-CPT. The median age at diagnosis was 2 years (range 10 months to 4 years), and all patients had Stage IV disease. All patients had unfavorable histologic characteristics (poorly differentiated histologic features in 8, N-Myc amplification in 6, and 1p/11q chromosomal abnormalities in 4). The median tumor size at diagnosis was 11.4 cm (range 7-16) in maximal dimension. At a median follow-up of 38 months (range 11-70), there were no local failures. Four patients developed distant failure, and, of these, two died of disease. Acute side effects included Grade 1 skin erythema in 5 patients and Grade 2 anorexia in 2 patients. Although comparable target coverage was achieved with all three modalities, proton therapy achieved substantial normal tissue sparing compared with IMRT. Intensity-modulated proton RT allowed additional sparing of the kidneys, lungs, and heart. Conclusions: Preliminary outcomes reveal excellent local control with proton therapy

  2. Reconfigurable Three-Dimensional Gold Nanorod Plasmonic Nanostructures Organized on DNA Origami Tripod.

    Science.gov (United States)

    Zhan, Pengfei; Dutta, Palash K; Wang, Pengfei; Song, Gang; Dai, Mingjie; Zhao, Shu-Xia; Wang, Zhen-Gang; Yin, Peng; Zhang, Wei; Ding, Baoquan; Ke, Yonggang

    2017-02-28

    Distinct electromagnetic properties can emerge from the three-dimensional (3D) configuration of a plasmonic nanostructure. Furthermore, the reconfiguration of a dynamic plasmonic nanostructure, driven by physical or chemical stimuli, may generate a tailored plasmonic response. In this work, we constructed a 3D reconfigurable plasmonic nanostructure with controllable, reversible conformational transformation using bottom-up DNA self-assembly. Three gold nanorods (AuNRs) were positioned onto a reconfigurable DNA origami tripod. The internanorod angle and distance were precisely tuned through operating the origami tripod by toehold-mediated strand displacement. The transduction of conformational change manifested into a controlled shift of the plasmonic resonance peak, which was studied by dark-field microscopy, and agrees well with electrodynamic calculations. This new 3D plasmonic nanostructure not only provides a method to study the plasmonic resonance of AuNRs at prescribed 3D conformations but also demonstrates that DNA origami can serve as a general self-assembly platform for constructing various 3D reconfigurable plasmonic nanostructures with customized optical properties.

  3. Keeping an eye on the ring: COMS plaque loading optimization for improved dose conformity and homogeneity.

    Science.gov (United States)

    Gagne, Nolan L; Cutright, Daniel R; Rivard, Mark J

    2012-09-01

    To improve tumor dose conformity and homogeneity for COMS plaque brachytherapy by investigating the dosimetric effects of varying component source ring radionuclides and source strengths. The MCNP5 Monte Carlo (MC) radiation transport code was used to simulate plaque heterogeneity-corrected dose distributions for individually-activated source rings of 14, 16 and 18 mm diameter COMS plaques, populated with (103)Pd, (125)I and (131)Cs sources. Ellipsoidal tumors were contoured for each plaque size and MATLAB programming was developed to generate tumor dose distributions for all possible ring weighting and radionuclide permutations for a given plaque size and source strength resolution, assuming a 75 Gy apical prescription dose. These dose distributions were analyzed for conformity and homogeneity and compared to reference dose distributions from uniformly-loaded (125)I plaques. The most conformal and homogeneous dose distributions were reproduced within a reference eye environment to assess organ-at-risk (OAR) doses in the Pinnacle(3) treatment planning system (TPS). The gamma-index analysis method was used to quantitatively compare MC and TPS-generated dose distributions. Concentrating > 97% of the total source strength in a single or pair of central (103)Pd seeds produced the most conformal dose distributions, with tumor basal doses a factor of 2-3 higher and OAR doses a factor of 2-3 lower than those of corresponding uniformly-loaded (125)I plaques. Concentrating 82-86% of the total source strength in peripherally-loaded (131)Cs seeds produced the most homogeneous dose distributions, with tumor basal doses 17-25% lower and OAR doses typically 20% higher than those of corresponding uniformly-loaded (125)I plaques. Gamma-index analysis found > 99% agreement between MC and TPS dose distributions. A method was developed to select intra-plaque ring radionuclide compositions and source strengths to deliver more conformal and homogeneous tumor dose distributions than

  4. Use of three-dimensional lognormal dose-response surfaces in lifetime studies of radiation-induced cancer

    International Nuclear Information System (INIS)

    Raabe, O.G.

    1986-01-01

    The three-dimensional lognormal cumulative probability power function was used to provide a unifying dose-response description of the lifetime cancer risk for chronic exposure of experimental animals and people, for risk evaluation, and for scaling between species. Bone tumor fatilities, primarily from alpha irradiation of the skeleton in lifetime studies of beagles injected with 226 Ra, were shown to be well described by this function. This function described cancer risk in lifetime studies as a curved smooth surface depending on radiation exposure rate and elapsed time, such that the principal risk at low dose rates occurred near the end of the normal life span without significant life shortening. Essentially identical functions with the median value of the power function displaced with respect to appropriate RBE values were shown to describe bone-cancer induction primarily from alpha irradiation of the skeleton in lifetime beagle studies with injected 226 Ra, 228 Th, 239 Pu and 241 Am, and with inhaled 238 Pu. Application of this model to human exposures to 226 Ra yielded a response ratio of 3.6; that is, the time required for development of bone cancer in people was 3.6 times longer than for beagles at the same average skeletal dose rate. It was suggested that similar techniques were appropriate to other carcinogens and other critical organs. 20 refs., 8 figs., 3 tabs

  5. Ewing sarcoma localized on spine: a dose escalation study in child

    International Nuclear Information System (INIS)

    Vogin, G.; Marchesi, V.; Biston, M.C.; Gassa, F.; Amessis, M.; Zefkili, S.; Helfre, S.; De Marzi, L.; Lacroix, F.; Leroy, A.

    2011-01-01

    The authors report the study of dose escalation for the treatment of spinal in two types of Ewing tumours. They used 5 dose levels at the rate of five 1,6 Gy per week. They compare different radiotherapy techniques: three-dimensional conformation radiotherapy, static intensity-modulated conformational radiotherapy, helical tomo-therapy, volume-modulated arc-therapy (VMAT), stereotactic radiotherapy, and proton-therapy (in passive diffusion). It appears that it is possible to safely and efficiently deliver until 70,4 Gy in some Ewing tumours. In child, exclusive radiotherapy might become a local treatment option and would require a clinic trial and comparison with exclusive surgery or post-operative radiotherapy. Short communication

  6. Bladder radiotherapy treatment: A retrospective comparison of 3-dimensional conformal radiotherapy, intensity-modulated radiation therapy, and volumetric-modulated arc therapy plans

    Energy Technology Data Exchange (ETDEWEB)

    Pasciuti, Katia, E-mail: k.pasciuti@virgilio.it [Department of Radiotherapy Physics, Royal Free Hospital, London (United Kingdom); Kuthpady, Shrinivas [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom); Anderson, Anne; Best, Bronagh [Department of Radiotherapy Physics, Royal Free Hospital, London (United Kingdom); Waqar, Saleem; Chowdhury, Subhra [Department of Radiotherapy, Royal Free Hospital, London (United Kingdom)

    2017-04-01

    To examine tumor's and organ's response when different radiotherapy plan techniques are used. Ten patients with confirmed bladder tumors were first treated using 3-dimensional conformal radiotherapy (3DCRT) and subsequently the original plans were re-optimized using the intensity-modulated radiation treatment (IMRT) and volumetric-modulated arc therapy (VMAT)-techniques. Targets coverage in terms of conformity and homogeneity index, TCP, and organs' dose limits, including integral dose analysis were evaluated. In addition, MUs and treatment delivery times were compared. Better minimum target coverage (1.3%) was observed in VMAT plans when compared to 3DCRT and IMRT ones confirmed by a statistically significant conformity index (CI) results. Large differences were observed among techniques in integral dose results of the femoral heads. Even if no statistically significant differences were reported in rectum and tissue, a large amount of energy deposition was observed in 3DCRT plans. In any case, VMAT plans provided better organs and tissue sparing confirmed also by the normal tissue complication probability (NTCP) analysis as well as a better tumor control probability (TCP) result. Our analysis showed better overall results in planning using VMAT techniques. Furthermore, a total time reduction in treatment observed among techniques including gantry and collimator rotation could encourage using the more recent one, reducing target movements and patient discomfort.

  7. The evolution of rectal and urinary toxicity and immune response in prostate cancer patients treated with two three-dimensional conformal radiotherapy techniques

    Czech Academy of Sciences Publication Activity Database

    Vránová, J.; Vinakurau, S.; Richter, J.; Starec, M.; Fišerová, Anna; Rosina, J.

    2011-01-01

    Roč. 2, č. 6 (2011), s. 1-13 ISSN 1748-717X R&D Projects: GA AV ČR IAA500200620 Institutional research plan: CEZ:AV0Z50200510 Keywords : 3-dimensional conformal radiotherapy (3DCRT) * gastrointestinal and genitourinary toxicity * prostate cancer Subject RIV: EC - Immunology Impact factor: 2.321, year: 2011

  8. The Figured Worlds of High School Science Teachers: Uncovering Three-Dimensional Assessment Decisions

    Science.gov (United States)

    Ewald, Megan

    As a result of recent mandates of the Next Generation Science Standards, assessments are a "system of meaning" amidst a paradigm shift toward three-dimensional assessments. This study is motivated by two research questions: 1) how do high school science teachers describe their processes of decision-making in the development and use of three-dimensional assessments and 2) how do high school science teachers negotiate their identities as assessors in designing three-dimensional assessments. An important factor in teachers' assessment decision making is how they identify themselves as assessors. Therefore, this study investigated the teachers' roles as assessors through the Sociocultural Identity Theory. The most important contribution from this study is the emergent teacher assessment sub-identities: the modifier-recycler , the feeler-finder, and the creator. Using a qualitative phenomenological research design, focus groups, three-series interviews, think-alouds, and document analysis were utilized in this study. These qualitative methods were chosen to elicit rich conversations among teachers, make meaning of the teachers' experiences through in-depth interviews, amplify the thought processes of individual teachers while making assessment decisions, and analyze assessment documents in relation to teachers' perspectives. The findings from this study suggest that--of the 19 participants--only two teachers could consistently be identified as creators and aligned their assessment practices with NGSS. However, assessment sub-identities are not static and teachers may negotiate their identities from one moment to the next within socially constructed realms of interpretation known as figured worlds. Because teachers are positioned in less powerful figured worlds within the dominant discourse of standardization, this study raises awareness as to how the external pressures from more powerful figured worlds socially construct teachers' identities as assessors. For teachers

  9. Estimation of pneumonitis risk in three-dimensional treatment planning using dose-volume histogram analysis

    International Nuclear Information System (INIS)

    Oetzel, Dieter; Schraube, Peter; Hensley, Frank; Sroka-Perez, Gabriele; Menke, Markus; Flentje, Michael

    1995-01-01

    Purpose: Investigations to study correlations between the estimations of biophysical models in three dimensional (3D) treatment planning and clinical observations are scarce. The development of clinically symptomatic pneumonitis in the radiotherapy of thoracic malignomas was chosen to test the predictive power of Lyman's normal tissue complication probability (NTCP) model for the assessment of side effects for nonuniform irradiation. Methods and Materials: In a retrospective analysis individual computed-tomography-based 3D dose distributions of a random sample of (46(20)) patients with lung/esophageal cancer were reconstructed. All patients received tumor doses between 50 and 60 Gy in a conventional treatment schedule. Biological isoeffective dose-volume histograms (DVHs) were used for the calculation of complication probabilities after applying Lyman's and Kutcher's DVH-reduction algorithm. Lung dose statistics were performed for single lung (involved ipsilateral and contralateral) and for the lung as a paired organ. Results: In the lung cancer group, about 20% of the patients (9 out of 46) developed pneumonitis 3-12 (median 7.5) weeks after completion of radiotherapy. For the majority of these lung cancer patients, the involved ipsilateral lung received a much higher dose than the contralateral lung, and the pneumonitis patients had on average a higher lung exposure with a doubling of the predicted complication risk (38% vs. 20%). The lower lung exposure for the esophagus patients resulted in a mean lung dose of 13.2 Gy (lung cancer: 20.5 Gy) averaged over all patients in correlation with an almost zero complication risk and only one observed case of pneumonitis (1 out of 20). To compare the pneumonitis risk estimations with observed complication rates, the patients were ranked into bins of mean ipsilateral lung dose. Particularly, in the bins with the highest patient numbers, a good correlation was achieved. Agreement was not reached for the lung functioning as

  10. Dosimetric comparison of standard three-dimensional conformal radiotherapy followed by intensity-modulated radiotherapy boost schedule (sequential IMRT plan) with simultaneous integrated boost-IMRT (SIB IMRT) treatment plan in patients with localized carcinoma prostate.

    Science.gov (United States)

    Bansal, A; Kapoor, R; Singh, S K; Kumar, N; Oinam, A S; Sharma, S C

    2012-07-01

    DOSIMETERIC AND RADIOBIOLOGICAL COMPARISON OF TWO RADIATION SCHEDULES IN LOCALIZED CARCINOMA PROSTATE: Standard Three-Dimensional Conformal Radiotherapy (3DCRT) followed by Intensity Modulated Radiotherapy (IMRT) boost (sequential-IMRT) with Simultaneous Integrated Boost IMRT (SIB-IMRT). Thirty patients were enrolled. In all, the target consisted of PTV P + SV (Prostate and seminal vesicles) and PTV LN (lymph nodes) where PTV refers to planning target volume and the critical structures included: bladder, rectum and small bowel. All patients were treated with sequential-IMRT plan, but for dosimetric comparison, SIB-IMRT plan was also created. The prescription dose to PTV P + SV was 74 Gy in both strategies but with different dose per fraction, however, the dose to PTV LN was 50 Gy delivered in 25 fractions over 5 weeks for sequential-IMRT and 54 Gy delivered in 27 fractions over 5.5 weeks for SIB-IMRT. The treatment plans were compared in terms of dose-volume histograms. Also, Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP) obtained with the two plans were compared. The volume of rectum receiving 70 Gy or more (V > 70 Gy) was reduced to 18.23% with SIB-IMRT from 22.81% with sequential-IMRT. SIB-IMRT reduced the mean doses to both bladder and rectum by 13% and 17%, respectively, as compared to sequential-IMRT. NTCP of 0.86 ± 0.75% and 0.01 ± 0.02% for the bladder, 5.87 ± 2.58% and 4.31 ± 2.61% for the rectum and 8.83 ± 7.08% and 8.25 ± 7.98% for the bowel was seen with sequential-IMRT and SIB-IMRT plans respectively. For equal PTV coverage, SIB-IMRT markedly reduced doses to critical structures, therefore should be considered as the strategy for dose escalation. SIB-IMRT achieves lesser NTCP than sequential-IMRT.

  11. Could 3-D conformal radiotherapy improve the overall survival for non-small cell lung cancer?

    International Nuclear Information System (INIS)

    Giraud, P.; Helfre, S.; Lavole, A.; Rosenwald, J.C.; Cosset, J.M.

    2002-01-01

    The conformal radiotherapy approach, three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT), is based on modern imaging modalities, efficient 3-D treatment planning systems, sophisticated immobilization devices and demanding quality assurance and treatment verification. The main goal of conformal radiotherapy is to ensure a high dose distribution tailored to the limits of the target volume while reducing exposure of healthy tissues. These techniques would then allow a further dose escalation increasing local control and survival. Non-small cell lung cancer (NSCLC) is one of the most difficult malignant tumors to be treated. It combines geometrical difficulties due to respiratory motion, and number of low tolerance neighboring organs, and dosimetric difficulties because of the presence of huge inhomogeneities. This localization is an attractive and ambitious example for the evaluation of new techniques. However, the published clinical reports in the last years described very heterogeneous techniques and, in the absence of prospective randomized trials, it is somewhat difficult at present to evaluate the real benefits drawn from those conformal radiotherapy techniques. After reviewing the rationale for 3DCRT for NSCLC, this paper will describe the main studies of 3DCRT, in order to evaluate its impact on lung cancer treatment Then the current state-of-the-art of IMRT and the last technical and therapeutic innovations in NSCL will be discussed. (authors)

  12. Prone Whole-Breast Irradiation Using Three-Dimensional Conformal Radiotherapy in Women Undergoing Breast Conservation for Early Disease Yields High Rates of Excellent to Good Cosmetic Outcomes in Patients With Large and/or Pendulous Breasts

    Energy Technology Data Exchange (ETDEWEB)

    Bergom, Carmen; Kelly, Tracy; Morrow, Natalya; Wilson, J. Frank [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States); Walker, Alonzo [Department of Surgery, Medical College of Wisconsin, Milwaukee, WI (United States); Xiang Qun; Ahn, Kwang Woo [Division of Biostatistics, Medical College of Wisconsin, Milwaukee, WI (United States); White, Julia, E-mail: jwhite@mcw.edu [Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI (United States)

    2012-07-01

    Purpose: To report our institution's experience using prone positioning for three-dimensional conformal radiotherapy (3D-CRT) to deliver post-lumpectomy whole breast irradiation (WBI) in a cohort of women with large and/or pendulous breasts, to determine the rate of acute and late toxicities and, more specifically, cosmetic outcomes. We hypothesized that using 3D-CRT for WBI in the prone position would reduce or eliminate patient and breast size as negative prognostic indicators for toxicities associated with WBI. Methods and Materials: From 1998 to 2006, 110 cases were treated with prone WBI using 3D-CRT. The lumpectomy, breast target volumes, heart, and lung were contoured on all computed tomography scans. A dose of 45-50 Gy was prescribed to the breast volume using standard fractionation schemes. The planning goals were {>=}95% of prescription to 95% of the breast volume, and 100% of boost dose to 95% of lumpectomy planning target volume. Toxicities and cosmesis were prospectively scored using the Common Terminology Criteria for Adverse Effects Version 3.0 and the Harvard Scale. The median follow-up was 40 months. Results: The median body mass index (BMI) was 33.6 kg/m{sup 2}, and median breast volume was 1396 cm{sup 3}. The worst toxicity encountered during radiation was Grade 3 dermatitis in 5% of our patient population. Moist desquamation occurred in 16% of patients, with only 2% of patients with moist desquamation outside the inframammary/axillary folds. Eleven percent of patients had Grade {>=}2 late toxicities, including Grade 3 induration/fibrosis in 2%. Excellent to good cosmesis was achieved in 89%. Higher BMI was associated with moist desquamation and breast pain, but BMI and breast volume did not impact fibrosis or excellent to good cosmesis. Conclusion: In patients with higher BMI and/or large-pendulous breasts, delivering prone WBI using 3D-CRT results in favorable toxicity profiles and high excellent to good cosmesis rates. Higher BMI was

  13. Three-dimensional porous graphene-Co{sub 3}O{sub 4} nanocomposites for high performance photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Bin, Zeng, E-mail: 21467855@qq.com [College of Mechanical Engineering, Hunan University of Arts and Science, Changde 415000 (China); Hui, Long [Department of Applied Physics and Materials Research Center, The Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong)

    2015-12-01

    Highlights: • The three-dimensional porous graphene-Co{sub 3}O{sub 4} nanocomposites were synthesized. • Excellent photocatalytic performance. • Separated from the reaction medium by magnetic decantation. - Abstract: Novel three-dimensional porous graphene-Co{sub 3}O{sub 4} nanocomposites were synthesized by freeze-drying methods. Scanning and transmission electron microscopy revealed that the graphene formed a three-dimensional porous structure with Co{sub 3}O{sub 4} nanoparticles decorated surfaces. The as-obtained product showed high photocatalytic efficiency and could be easily separated from the reaction medium by magnetic decantation. This nanocomposite may be expected to have potential in water purification applications.

  14. Preliminary Toxicity Analysis of 3-Dimensional Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy on the High-Dose Arm of the Radiation Therapy Oncology Group 0126 Prostate Cancer Trial

    Energy Technology Data Exchange (ETDEWEB)

    Michalski, Jeff M., E-mail: jmichalski@radonc.wustl.edu [Department of Radiation Oncology Washington University Medical Center, St. Louis, Missouri (United States); Yan, Yan [Radiation Therapy Oncology Group Statistical Center, Philadelphia, Pennsylvania (United States); Watkins-Bruner, Deborah [Emory University School of Nursing, Atlanta, Georgia (United States); Bosch, Walter R. [Department of Radiation Oncology Washington University Medical Center, St. Louis, Missouri (United States); Winter, Kathryn [Radiation Therapy Oncology Group Statistical Center, Philadelphia, Pennsylvania (United States); Galvin, James M. [Department of Radiation Oncology Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Bahary, Jean-Paul [Department of Radiation Oncology Centre Hospitalier de l' Université de Montréal-Notre Dame, Montreal, QC (Canada); Morton, Gerard C. [Department of Radiation Oncology Toronto-Sunnybrook Regional Cancer Centre, Toronto, ON (Canada); Parliament, Matthew B. [Department of Oncology Cross Cancer Institute, Edmonton, AB (Canada); Sandler, Howard M. [Department of Radiation Oncology Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California (United States)

    2013-12-01

    Purpose: To give a preliminary report of clinical and treatment factors associated with toxicity in men receiving high-dose radiation therapy (RT) on a phase 3 dose-escalation trial. Methods and Materials: The trial was initiated with 3-dimensional conformal RT (3D-CRT) and amended after 1 year to allow intensity modulated RT (IMRT). Patients treated with 3D-CRT received 55.8 Gy to a planning target volume that included the prostate and seminal vesicles, then 23.4 Gy to prostate only. The IMRT patients were treated to the prostate and proximal seminal vesicles to 79.2 Gy. Common Toxicity Criteria, version 2.0, and Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late morbidity scores were used for acute and late effects. Results: Of 763 patients randomized to the 79.2-Gy arm of Radiation Therapy Oncology Group 0126 protocol, 748 were eligible and evaluable: 491 and 257 were treated with 3D-CRT and IMRT, respectively. For both bladder and rectum, the volumes receiving 65, 70, and 75 Gy were significantly lower with IMRT (all P<.0001). For grade (G) 2+ acute gastrointestinal/genitourinary (GI/GU) toxicity, both univariate and multivariate analyses showed a statistically significant decrease in G2+ acute collective GI/GU toxicity for IMRT. There were no significant differences with 3D-CRT or IMRT for acute or late G2+ or 3+ GU toxicities. Univariate analysis showed a statistically significant decrease in late G2+ GI toxicity for IMRT (P=.039). On multivariate analysis, IMRT showed a 26% reduction in G2+ late GI toxicity (P=.099). Acute G2+ toxicity was associated with late G3+ toxicity (P=.005). With dose–volume histogram data in the multivariate analysis, RT modality was not significant, whereas white race (P=.001) and rectal V70 ≥15% were associated with G2+ rectal toxicity (P=.034). Conclusions: Intensity modulated RT is associated with a significant reduction in acute G2+ GI/GU toxicity. There is a trend for a

  15. Knowledge-based prediction of three-dimensional dose distributions for external beam radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Shiraishi, Satomi; Moore, Kevin L., E-mail: kevinmoore@ucsd.edu [Department of Radiation Medicine and Applied Sciences, University of California, San Diego, La Jolla, California 92093 (United States)

    2016-01-15

    Purpose: To demonstrate knowledge-based 3D dose prediction for external beam radiotherapy. Methods: Using previously treated plans as training data, an artificial neural network (ANN) was trained to predict a dose matrix based on patient-specific geometric and planning parameters, such as the closest distance (r) to planning target volume (PTV) and organ-at-risks (OARs). Twenty-three prostate and 43 stereotactic radiosurgery/radiotherapy (SRS/SRT) cases with at least one nearby OAR were studied. All were planned with volumetric-modulated arc therapy to prescription doses of 81 Gy for prostate and 12–30 Gy for SRS. Using these clinically approved plans, ANNs were trained to predict dose matrix and the predictive accuracy was evaluated using the dose difference between the clinical plan and prediction, δD = D{sub clin} − D{sub pred}. The mean (〈δD{sub r}〉), standard deviation (σ{sub δD{sub r}}), and their interquartile range (IQR) for the training plans were evaluated at a 2–3 mm interval from the PTV boundary (r{sub PTV}) to assess prediction bias and precision. Initially, unfiltered models which were trained using all plans in the cohorts were created for each treatment site. The models predict approximately the average quality of OAR sparing. Emphasizing a subset of plans that exhibited superior to the average OAR sparing during training, refined models were created to predict high-quality rectum sparing for prostate and brainstem sparing for SRS. Using the refined model, potentially suboptimal plans were identified where the model predicted further sparing of the OARs was achievable. Replans were performed to test if the OAR sparing could be improved as predicted by the model. Results: The refined models demonstrated highly accurate dose distribution prediction. For prostate cases, the average prediction bias for all voxels irrespective of organ delineation ranged from −1% to 0% with maximum IQR of 3% over r{sub PTV} ∈ [ − 6, 30] mm. The

  16. Pelvic nodal dose escalation with prostate hypofractionation using conformal avoidance defined (H-CAD) intensity modulated radiation therapy

    International Nuclear Information System (INIS)

    Hong, Theodore S.; Tome, Wolfgang A.; Jaradat, Hazim; Raisbeck, Bridget M.; Ritter, Mark A.

    2006-01-01

    % of both the PTV 70 (prostate) and PTV 56 (nodes). The EUDs for PTV 70 and PTV 56 were greater than prescription dose for all eight plans. Analysis of bio-effective DVHs demonstrated similar amounts of small bowel receiving >45 Gy for H-CAD and sequential plans, in spite of the significantly higher dose to which H-CAD treated the pelvic nodes. The treatment was well tolerated in the eight treated patients in that no grade 2 or higher acute gastrointestinal toxicities were seen. Prostate hypofractionation with concurrent conformal avoidance-based pelvic IMRT for high risk prostate cancer represents an efficient and promising method for achieving dose escalation both of pelvic lymph nodes and the prostate with modest acute toxicity. Unlike a vascular-guided targeting approach, conformal avoidance has the potential advantage of also encompassing at-risk nodes that are not contained within major nodal chains. A phase II trial to more thoroughly examine this treatment approach is currently underway

  17. Multiparallel Three-Dimensional Optical Microscopy

    Science.gov (United States)

    Nguyen, Lam K.; Price, Jeffrey H.; Kellner, Albert L.; Bravo-Zanoquera, Miguel

    2010-01-01

    Multiparallel three-dimensional optical microscopy is a method of forming an approximate three-dimensional image of a microscope sample as a collection of images from different depths through the sample. The imaging apparatus includes a single microscope plus an assembly of beam splitters and mirrors that divide the output of the microscope into multiple channels. An imaging array of photodetectors in each channel is located at a different distance along the optical path from the microscope, corresponding to a focal plane at a different depth within the sample. The optical path leading to each photodetector array also includes lenses to compensate for the variation of magnification with distance so that the images ultimately formed on all the photodetector arrays are of the same magnification. The use of optical components common to multiple channels in a simple geometry makes it possible to obtain high light-transmission efficiency with an optically and mechanically simple assembly. In addition, because images can be read out simultaneously from all the photodetector arrays, the apparatus can support three-dimensional imaging at a high scanning rate.

  18. Ewing sarcoma localized on spine: a dose escalation study in child; Sarcome d'Ewing localise au rachis: une etude d'escalade de dose chez l'enfant

    Energy Technology Data Exchange (ETDEWEB)

    Vogin, G.; Marchesi, V. [Centre Alexis-Vautrin, Nancy (France); Biston, M.C.; Gassa, F. [Centre Leon-Berard, Lyon (France); Amessis, M.; Zefkili, S.; Helfre, S. [Institut Curie, Paris (France); De Marzi, L.; Lacroix, F.; Leroy, A. [Institut Curie, Orsay (France)

    2011-10-15

    The authors report the study of dose escalation for the treatment of spinal in two types of Ewing tumours. They used 5 dose levels at the rate of five 1,6 Gy per week. They compare different radiotherapy techniques: three-dimensional conformation radiotherapy, static intensity-modulated conformational radiotherapy, helical tomo-therapy, volume-modulated arc-therapy (VMAT), stereotactic radiotherapy, and proton-therapy (in passive diffusion). It appears that it is possible to safely and efficiently deliver until 70,4 Gy in some Ewing tumours. In child, exclusive radiotherapy might become a local treatment option and would require a clinic trial and comparison with exclusive surgery or post-operative radiotherapy. Short communication

  19. Three-dimensional bio-printing.

    Science.gov (United States)

    Gu, Qi; Hao, Jie; Lu, YangJie; Wang, Liu; Wallace, Gordon G; Zhou, Qi

    2015-05-01

    Three-dimensional (3D) printing technology has been widely used in various manufacturing operations including automotive, defence and space industries. 3D printing has the advantages of personalization, flexibility and high resolution, and is therefore becoming increasingly visible in the high-tech fields. Three-dimensional bio-printing technology also holds promise for future use in medical applications. At present 3D bio-printing is mainly used for simulating and reconstructing some hard tissues or for preparing drug-delivery systems in the medical area. The fabrication of 3D structures with living cells and bioactive moieties spatially distributed throughout will be realisable. Fabrication of complex tissues and organs is still at the exploratory stage. This review summarize the development of 3D bio-printing and its potential in medical applications, as well as discussing the current challenges faced by 3D bio-printing.

  20. A comparison of different three-dimensional treatment planning techniques for localized radiotherapy of prostate cancer

    International Nuclear Information System (INIS)

    Koswig, S.; Dinges, S.; Buchali, A.; Boehmer, D.; Salk, J.; Rosenthal, P.; Harder, C.; Schlenger, L.; Budach, V.

    1999-01-01

    Purpose: Four different three-dimensional planning techniques for localized radiotherapy of prostate cancer were compared with regard to dose homogeneity within the target volume and dose to organs at risk, dependent upon tumor stage. Patients and Methods: Six patients with stage T1, 7 patients with stage T2 and 4 patients with stage T3 were included in this study. Four different 3D treatment plans (rotation, 4-field, 5-field and 6-field technique) were calculated for each patient. Dose was calculated with the reference point at the isocenter (100%). The planning target volume was encompassed within the 95% isodose surface. All the techniques used different shaped portal for each beam. Dose volume histograms were created and compared for the planning target volume and the organs at risk (33%, 50%, 66% volume level) in all techniques. Results: The 4 different three-dimensional planning techniques revealed no differences concerning dose homogeneity within the planning target volume. The dose volume distribution at organs at risk show differences between the calculated techniques. In our study the best protection for bladder and rectum in stage T1 and T2 was achieved by the 6-field technique. A significant difference was achieved between 6-field and 4-field technique only in the 50% volume of the bladder (p=0.034), between the 6-field and rotation technique (all volume levels) and between 5-field and rotation technique (all volume levels). In stage T1, T2 6-field and 4-field technique in 50% (p-0.033) and 66% (p=0.011) of the rectum volume. In stage T3 a significant difference was not observed between the 4 techniques. The best protection of head of the femur was achieved by the rotation technique. Conclusion: In the localized radiotherapy of prostate cancer in stage T1 or T2 the best protection for bladder and rectum was achieved by a 3D-planned conformal 6-field technique. If the seminal vesicles have been included in the target volume and in the case of large

  1. Three-dimensional instability of standing waves

    Science.gov (United States)

    Zhu, Qiang; Liu, Yuming; Yue, Dick K. P.

    2003-12-01

    We investigate the three-dimensional instability of finite-amplitude standing surface waves under the influence of gravity. The analysis employs the transition matrix (TM) approach and uses a new high-order spectral element (HOSE) method for computation of the nonlinear wave dynamics. HOSE is an extension of the original high-order spectral method (HOS) wherein nonlinear wave wave and wave body interactions are retained up to high order in wave steepness. Instead of global basis functions in HOS, however, HOSE employs spectral elements to allow for complex free-surface geometries and surface-piercing bodies. Exponential convergence of HOS with respect to the total number of spectral modes (for a fixed number of elements) and interaction order is retained in HOSE. In this study, we use TM-HOSE to obtain the stability of general three-dimensional perturbations (on a two-dimensional surface) on two classes of standing waves: plane standing waves in a rectangular tank; and radial/azimuthal standing waves in a circular basin. For plane standing waves, we confirm the known result of two-dimensional side-bandlike instability. In addition, we find a novel three-dimensional instability for base flow of any amplitude. The dominant component of the unstable disturbance is an oblique (standing) wave oriented at an arbitrary angle whose frequency is close to the (nonlinear) frequency of the original standing wave. This finding is confirmed by direct long-time simulations using HOSE which show that the nonlinear evolution leads to classical Fermi Pasta Ulam recurrence. For the circular basin, we find that, beyond a threshold wave steepness, a standing wave (of nonlinear frequency Omega) is unstable to three-dimensional perturbations. The unstable perturbation contains two dominant (standing-wave) components, the sum of whose frequencies is close to 2Omega. From the cases we consider, the critical wave steepness is found to generally decrease/increase with increasing radial

  2. Evaluation of xerostomia following 3 dimensional conformal radiotherapy for nasopharyngeal cancer patients

    International Nuclear Information System (INIS)

    Park, Young Je; Ahn, Yong Chan; Park, Won; Ju, Sang Gyu; Nam, Hee Rim; Oh, Dong Ryul; Park, Hee Chul

    2006-01-01

    This study is to evaluate the xerostomia following 3-dimensional conformal radiation therapy (3D CRT) in nasopharynx cancer patients using the xerostomia questionnaire score (XQS). Questionnaire study was done on 51 patients with nasopharynx cancer who received 3D CRT from Dec. 2000 to Aug. 2005. 3D CRT technique is based on 'serial shrinking field' concept by 3 times of computed tomography (CT) simulation. Total target dose to the primary tumor was 72 Gy with 1.8 Gy daily fractions. Xerostomia was assessed with 4-questions XQS, and the associations between XQS and time elapsed after RT, age, sex, stage, concurrent chemotherapy, an parotid dose were analyzed. Concurrent chemotherapy was given to 40 patients and RT alone was given to 11 patients. The median time elapsed after 3D CRT was 20 (1 ∼ 58) months and the mean XQS of all 51 patients was 8.4 ± 1.9 (6 ∼ 14). XQS continuously and significantly decreased over time after 3D CRT (χ 2 -0.484, ρ < 0.05). There was no significant difference in XQS according to sex, age, and stag. However, XQS of concurrent chemotherapy patients was significantly higher than RT alone patients (ρ = 0.001). XQS of patients receiving total mean parotid dose ≥ 35 Gy was significantly higher than < 35 Gy (ρ = 0.05). Decreasing tendency of XQS over time after 3D CRT was observed. Concurrent chemotherapy and total mean parotid dose ≥ 35 Gy were suggested to adversely affect radiation-induced xerostomia

  3. Using DNase Hi-C techniques to map global and local three-dimensional genome architecture at high resolution.

    Science.gov (United States)

    Ma, Wenxiu; Ay, Ferhat; Lee, Choli; Gulsoy, Gunhan; Deng, Xinxian; Cook, Savannah; Hesson, Jennifer; Cavanaugh, Christopher; Ware, Carol B; Krumm, Anton; Shendure, Jay; Blau, C Anthony; Disteche, Christine M; Noble, William S; Duan, ZhiJun

    2018-06-01

    The folding and three-dimensional (3D) organization of chromatin in the nucleus critically impacts genome function. The past decade has witnessed rapid advances in genomic tools for delineating 3D genome architecture. Among them, chromosome conformation capture (3C)-based methods such as Hi-C are the most widely used techniques for mapping chromatin interactions. However, traditional Hi-C protocols rely on restriction enzymes (REs) to fragment chromatin and are therefore limited in resolution. We recently developed DNase Hi-C for mapping 3D genome organization, which uses DNase I for chromatin fragmentation. DNase Hi-C overcomes RE-related limitations associated with traditional Hi-C methods, leading to improved methodological resolution. Furthermore, combining this method with DNA capture technology provides a high-throughput approach (targeted DNase Hi-C) that allows for mapping fine-scale chromatin architecture at exceptionally high resolution. Hence, targeted DNase Hi-C will be valuable for delineating the physical landscapes of cis-regulatory networks that control gene expression and for characterizing phenotype-associated chromatin 3D signatures. Here, we provide a detailed description of method design and step-by-step working protocols for these two methods. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. A novel correction factor based on extended volume to complement the conformity index.

    Science.gov (United States)

    Jin, F; Wang, Y; Wu, Y-Z

    2012-08-01

    We propose a modified conformity index (MCI), based on extended volume, that improves on existing indices by correcting for the insensitivity of previous conformity indices to reference dose shape to assess the quality of high-precision radiation therapy and present an evaluation of its application. In this paper, the MCI is similar to the conformity index suggested by Paddick (CI(Paddick)), but with a different correction factor. It is shown for three cases: with an extended target volume, with an extended reference dose volume and without an extended volume. Extended volume is generated by expanding the original volume by 0.1-1.1 cm isotropically. Focusing on the simulation model, measurements of MCI employ a sphere target and three types of reference doses: a sphere, an ellipsoid and a cube. We can constrain the potential advantage of the new index by comparing MCI with CI(Paddick). The measurements of MCI in head-neck cancers treated with intensity-modulated radiation therapy and volumetric-modulated arc therapy provide a window on its clinical practice. The results of MCI for a simulation model and clinical practice are presented and the measurements are corrected for limited spatial resolution. The three types of MCI agree with each other, and comparisons between the MCI and CI(Paddick) are also provided. The results from our analysis show that the proposed MCI can provide more objective and accurate conformity measurement for high-precision radiation therapy. In combination with a dose-volume histogram, it will be a more useful conformity index.

  5. Radiophotoluminescence light scope for high-dose dosimetry

    International Nuclear Information System (INIS)

    Sato, Fuminobu; Zushi, Naoki; Sakiyama, Tomoki; Kato, Yushi; Murata, Isao; Shimizu, Kikuo; Yamamoto, Takayoshi; Iida, Toshiyuki

    2015-01-01

    A radiophotoluminescence (RPL) light scope is a remote-sensing technique for measuring in situ the radiation dose in an RPL detector placed at a distance. The RPL light scope is mainly composed of an ultraviolet (UV) pulse laser, telescopic lenses, a photomultiplier tube, and camera modules. In a performance test, some RPL detectors were placed at distances up to 30 m and were illuminated with a pulsed UV laser beam. The photoluminescence responses of the RPL detectors were analyzed using this scope. Their radiation doses were determined from the amplitude of the given component of the photoluminescence responses. The RPL readout could be repeated without fading, and its amplitude exhibited good linearity at a dose ranging from 0.1 to 60 Gy. Furthermore, a two-dimensional distribution of radiation dose was obtained by laser scanning on an RPL detector. It was confirmed that the RPL light scope was a useful remote-sensing tool for high-dose dosimetry. - Highlights: • A radiophotoluminescence (RPL) light scope was developed for high-dose dosimetry. • The RPL light scope has high sensitivity and accuracy in high-dose dosimetry. • Two-dimensional radiation dose distribution was obtained by the RPL light scope.

  6. SU-E-T-278: Dose Conformity Index for the Target in a Multitarget Environment

    Energy Technology Data Exchange (ETDEWEB)

    Harikrishnaperumal, Sudahar [Apollo Speciality Hospital, Chennai, Tamil Nadu (India)

    2015-06-15

    Purpose: The existing conformity index formulations are failing when multiple targets present outside the target of interest with same or different dose prescriptions. In the present study a novel methodology is introduced to solve this issue. Methods: The conformity index used by Nakamura et al (Int J Radiat Oncol Biol Phys 2001; 51(5):1313–1319) is taken as the base for this methodology. In this proposal, the prescription isodose volume (PIV) which normally includes the normal tissue and other target regions is restricted as PIV in annular regions of different thickness around the target of interest. The graphical line plotted between the thickness of annular region and the corresponding conformity index, will increase in the beginning and will reach a flat region, then it will increase again. The second increase in the conformity index depends basically on the distance between the targets, dose prescriptions, and size of the targets. The conformity index in the flat region should be the conformity index of the target of interest. This methodology was validated on dual target environment on a skull phantom in Multiplan planning system (Accuray Inc. Sunnyvale, USA) Results: When the surrounding target’s (sphere) size is changed from 1.5cm to 6cm diameter, the conformity index of the target of interest (3cm diameter) changed from 1.09 to 1.25. When the distance between the targets changed from 7.5cm to 2.5cm, the conformity index changed from 1.10 to 1.17. Similarly, when the prescribed dose changed from 25Gy to 50Gy the conformity index changed from 1.09 to 1.42. These values were above 2.0 when Nakamura et al formula was used. Conclusion: The proposed conformity index methodology eliminates the influence of surrounding targets to a greater extend. However, the limitations of this method should be studied further. Application of this method in clinical situations is the future scope.

  7. 3-D conformal treatment of prostate cancer to 74 Gy vs. high-dose-rate brachytherapy boost: A cross-sectional quality-of-life survey

    International Nuclear Information System (INIS)

    Vordermark, Dirk

    2006-01-01

    The effects of two modalities of dose-escalated radiotherapy on health-related quality of life (HRQOL) were compared. Forty-one consecutive patients were treated with a 3-D conformal (3-DC) boost to 74 Gy, and 43 with high-dose rate (HDR) brachytherapy boost (2x9 Gy), following 3-D conformal treatment to 46 Gy. Median age was 70 years in both groups, median initial PSA was 7.9 μg/l in 3-DC boost patients and 8.1 μg/l in HDR boost patients. Stage was 7 in 52% and 47%, respectively. HRQOL was assessed cross-sectionally using EORTC QLQ-C30 and organ-specific PR25 modules 3-32 (median 19) and 4-25 (median 14) months after treatment, respectively. Questionnaires were completed by 93% and 97% of patients, respectively. Diarrhea and insomnia scores were significantly increased in both groups. In the PR25 module, scores of 3-DC boost and HDR boost patients for urinary, bowel and treatment-related symptoms were similar. Among responders, 34% of 3-DC boost patients and 86% of HDR boost patients had severe erectile problems. Dose escalation in prostate cancer by either 3-DC boost to 74 Gy or HDR brachytherapy boost appears to result in similar HRQOL profiles

  8. Strategies to evaluate the impact of rectal volume on prostate motion during three-dimensional conformal radiotherapy for prostate cancer

    Directory of Open Access Journals (Sweden)

    Ana Paula Diniz Fortuna Poli

    2016-02-01

    Full Text Available Abstract Objective: To evaluate the rectal volume influence on prostate motion during three-dimensional conformal radiotherapy (3D-CRT for prostate cancer. Materials and Methods: Fifty-one patients with prostate cancer underwent a series of three computed tomography scans including an initial planning scan and two subsequent scans during 3D-CRT. The organs of interest were outlined. The prostate contour was compared with the initial CT images considering the anterior, posterior, superior, inferior and lateral edges of the organ. Variations in the anterior limits and volume of the rectum were assessed and correlated with prostate motion in the anteroposterior direction. Results: The maximum range of prostate motion was observed in the superoinferior direction, followed by the anteroposterior direction. A significant correlation was observed between prostate motion and rectal volume variation ( p = 0.037. A baseline rectal volume superior to 70 cm3 had a significant influence on the prostate motion in the anteroposterior direction ( p = 0.045. Conclusion: The present study showed a significant interfraction motion of the prostate during 3D-CRT with greatest variations in the superoinferior and anteroposterior directions, and that a large rectal volume influences the prostate motion with a cutoff value of 70 cm3. Therefore, the treatment of patients with a rectal volume > 70 cm3 should be re-planned with appropriate rectal preparation.

  9. Three-dimensional high dose rate dosimetry of electron beams. A combined radiochromic film, EPR and calorimetric dosimetry

    International Nuclear Information System (INIS)

    Secerov, B.; Milosavljevic, B.H.; Bacic, G.; Belgrade Univ.

    2002-01-01

    Complete text of publication follows. Aim. To examine the suitability of radiochromic film (RCF) dosimeters in determining 3D dose distribution from a pulsed electron beam source by comparing their response with alanine EPR dosimetry and calorimetry. Experimental. A FWT-60 radiochromic films (Far West Technology Inc) were used while alanine films were home made. To obtain the dose vs. penetration depth relationship, a stack of 13 films separated by aluminium plates and/or alanine films was placed perpendicular to the electron beam (Febetron, 20 ns, 1.8 MeV, 10 12 Gy/s, dose range up to 100 kGy). RC films were calibrated using 60-Co source and Fricke dosimetry. The absorbance of irradiated films was measured using 2D microdensitometry. Calorimetry was performed with a homemade quasy-adiabatic aluminum calorimeter. Results and Discussion. Microdensitometry of films (5 x 5 cm) enabled the 3D mapping of the entire radiation field with in plane resolution of 0.12 mm. The total dose for each film was obtained by image segmentation to correct for the non-linear response of films. Integrated dose for the entire stack was in good agreement (within 5%) with total absorbed energy as determined with calorimetry. The dose distribution along the beam center was determined using alanine films (1 x 1 cm) and EPR spectroscopy, and again a good agreement with the dose determined by microdensitometry of the central portion of RC films. In conclusion, the results indicate that RC films can be used for determination of 3D dose distribution even at very high dose rates

  10. Creation of three-dimensional craniofacial standards from CBCT images

    Science.gov (United States)

    Subramanyan, Krishna; Palomo, Martin; Hans, Mark

    2006-03-01

    Low-dose three-dimensional Cone Beam Computed Tomography (CBCT) is becoming increasingly popular in the clinical practice of dental medicine. Two-dimensional Bolton Standards of dentofacial development are routinely used to identify deviations from normal craniofacial anatomy. With the advent of CBCT three dimensional imaging, we propose a set of methods to extend these 2D Bolton Standards to anatomically correct surface based 3D standards to allow analysis of morphometric changes seen in craniofacial complex. To create 3D surface standards, we have implemented series of steps. 1) Converting bi-plane 2D tracings into set of splines 2) Converting the 2D splines curves from bi-plane projection into 3D space curves 3) Creating labeled template of facial and skeletal shapes and 4) Creating 3D average surface Bolton standards. We have used datasets from patients scanned with Hitachi MercuRay CBCT scanner providing high resolution and isotropic CT volume images, digitized Bolton Standards from age 3 to 18 years of lateral and frontal male, female and average tracings and converted them into facial and skeletal 3D space curves. This new 3D standard will help in assessing shape variations due to aging in young population and provide reference to correct facial anomalies in dental medicine.

  11. Does Three-Dimensional External Beam Partial Breast Irradiation Spare Lung Tissue Compared With Standard Whole Breast Irradiation?

    International Nuclear Information System (INIS)

    Jain, Anudh K.; Vallow, Laura A.; Gale, Ashley A.; Buskirk, Steven J.

    2009-01-01

    Purpose: To determine whether three-dimensional conformal partial breast irradiation (3D-PBI) spares lung tissue compared with whole breast irradiation (WBI) and to include the biologically equivalent dose (BED) to account for differences in fractionation. Methods and Materials: Radiotherapy treatment plans were devised for WBI and 3D-PBI for 25 consecutive patients randomized on the NSABP B-39/RTOG 0413 protocol at Mayo Clinic in Jacksonville, Florida. WBI plans were for 50 Gy in 25 fractions, and 3D-PBI plans were for 38.5 Gy in 10 fractions. Volume of ipsilateral lung receiving 2.5, 5, 10, and 20 Gy was recorded for each plan. The linear quadratic equation was used to calculate the corresponding dose delivered in 10 fractions and volume of ipsilateral lung receiving these doses was recorded for PBI plans. Ipsilateral mean lung dose was recorded for each plan and converted to BED. Results: There was a significant decrease in volume of lung receiving 20 Gy with PBI (median, 4.4% vs. 7.5%; p 3 vs 4.85 Gy 3 , p = 0.07). PBI plans exposed more lung to 2.5 and 5 Gy. Conclusions: 3D-PBI exposes greater volumes of lung tissue to low doses of radiation and spares the amount of lung receiving higher doses when compared with WBI.

  12. Three-dimensional dose accumulation in pseudo-split-field IMRT and brachytherapy for locally advanced cervical cancer

    DEFF Research Database (Denmark)

    Sun, Baozhou; Yang, Deshan; Esthappan, Jackie

    2015-01-01

    -field intensity-modulated radiation therapy (IMRT) and image-guided BT in locally advanced cervical cancer. METHODS AND MATERIALS: Thirty-three patients treated with split-field-IMRT to 45.0-51.2 Gy in 1.6-1.8 Gy per fraction to the elective pelvic lymph nodes and to 20 Gy to the central pelvis region were...... included in this study. Patients received six weekly fractions of high-dose rate BT to 6.5-7.3 Gy per fraction. A dose tracker software was developed to compute the equivalent dose in 2-Gy fractions (EQD2) to gross tumor volume (GTV), organs-at-risk and point A. Total dose-volume histogram parameters were...

  13. Three-Dimensional Porous Nitrogen-Doped NiO Nanostructures as Highly Sensitive NO2 Sensors

    Directory of Open Access Journals (Sweden)

    Van Hoang Luan

    2017-10-01

    Full Text Available Nickel oxide has been widely used in chemical sensing applications, because it has an excellent p-type semiconducting property with high chemical stability. Here, we present a novel technique of fabricating three-dimensional porous nitrogen-doped nickel oxide nanosheets as a highly sensitive NO2 sensor. The elaborate nanostructure was prepared by a simple and effective hydrothermal synthesis method. Subsequently, nitrogen doping was achieved by thermal treatment with ammonia gas. When the p-type dopant, i.e., nitrogen atoms, was introduced in the three-dimensional nanostructures, the nickel-oxide-nanosheet-based sensor showed considerable NO2 sensing ability with two-fold higher responsivity and sensitivity compared to non-doped nickel-oxide-based sensors.

  14. Three-dimensional ICT reconstruction

    International Nuclear Information System (INIS)

    Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

    2005-01-01

    The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context, qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

  15. Three-dimensional ICT reconstruction

    International Nuclear Information System (INIS)

    Zhang Aidong; Li Ju; Chen Fa; Sun Lingxia

    2004-01-01

    The three-dimensional ICT reconstruction method is the hot topic of recent ICT technology research. In the context qualified visual three-dimensional ICT pictures are achieved through multi-piece two-dimensional images accumulation by order, combining with thresholding method and linear interpolation. Different direction and different position images of the reconstructed pictures are got by rotation and interception respectively. The convenient and quick method is significantly instructive to more complicated three-dimensional reconstruction of ICT images. (authors)

  16. Three-dimensional graphene/polyaniline composite material for high-performance supercapacitor applications

    International Nuclear Information System (INIS)

    Liu, Huili; Wang, Yi; Gou, Xinglong; Qi, Tao; Yang, Jun; Ding, Yulong

    2013-01-01

    Highlights: ► A novel 3D graphene showed high specific surface area and large mesopore volume. ► Aniline monomer was polymerized in the presence of 3D graphene at room temperature. ► The supercapacitive properties were studied by CV and charge–discharge tests. ► The composite show a high gravimetric capacitance and good cyclic stability. ► The 3D graphene/polyaniline has never been report before our work. -- Abstract: A novel three-dimensional (3D) graphene/polyaniline nanocomposite material which is synthesized using in situ polymerization of aniline monomer on the graphene surface is reported as an electrode for supercapacitors. The morphology and structure of the material are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The electrochemical properties of the resulting materials are systematically studied using cyclic voltammetry (CV) and constant current charge–discharge tests. A high gravimetric capacitance of 463 F g −1 at a scan rate of 1 mV s −1 is obtained by means of CVs with 3 mol L −1 KOH as the electrolyte. In addition, the composite material shows only 9.4% capacity loss after 500 cycles, indicating better cyclic stability for supercapacitor applications. The high specific surface area, large mesopore volume and three-dimensional nanoporous structure of 3D graphene could contribute to the high specific capacitance and good cyclic life

  17. Long-term follow-up of a phase I/II trial of dose escalating three-dimensional conformal thoracic radiation therapy with induction and concurrent carboplatin and paclitaxel in unresectable stage IIIA/B non-small cell lung cancer.

    Science.gov (United States)

    Stinchcombe, Thomas E; Lee, Carrie B; Moore, Dominic T; Rivera, M Patricia; Halle, Jan; Limentani, Steven; Rosenman, Julian G; Socinski, Mark A

    2008-11-01

    We conducted a modified phase I/II trial investigating the incorporation of three-dimensional conformal thoracic radiation therapy (TCRT) into the treatment paradigm of induction and concurrent carboplatin and paclitaxel in patients with unresectable stage IIIA/B non-small cell lung cancer. Patients received 2 cycles of induction carboplatin (area under the curve of 6) and paclitaxel (225 mg/m) on days 1, and 22. On day 43 concurrent TCRT and weekly x6 of carboplatin (area under the curve = 2) and paclitaxel (45 mg/m) was initiated. The TCRT dose was escalated from 60 to 74 Gy in 4 cohorts (60, 66, 70, and 74 Gy), and the 74 Gy cohort was expanded into a phase II trial. Sixty-two patients were enrolled; the median age 57 years (range, 36-82), 39 were male (63%), 61 (98%) had a performance status of 0 or 1, 28 (45%) had stage IIIA disease, 21 (34%) had >5% weight loss, and the median forced expiratory volume 1 = 2.10 liters (range, 1.02-3.75). With a median follow-up for survivors of approximately 9 years (range, 7-11 years) the median progression-free survival, time to tumor progression, and overall survival (OS) (with 95% confidence intervals) were 10 (8.5-17), 15 (9-50), and 25 months (18-37), respectively. The 5-year progression-free survival and OS rates were 21% (12-32%) and 27% (17-39%), respectively. The 10-year OS rate was 14% (7-25%). The long term survival rate compares favorably to other treatment approaches for stage III non-small cell lung cancer.

  18. Acute and Late Toxicity in a Randomized Trial of Conventional Versus Hypofractionated Three-Dimensional Conformal Radiotherapy for Prostate Cancer

    International Nuclear Information System (INIS)

    Arcangeli, Giorgio; Fowler, Jack; Gomellini, Sara; Arcangeli, Stefano; Saracino, Biancamaria; Petrongari, Maria Grazia; Benassi, Marcello; Strigari, Lidia

    2011-01-01

    Purpose: To compare the toxicity between hypofractionation vs. conventional fractionation schedules in patients with high-risk prostate cancer. Methods and Materials: Between January 2003 and December 2007, 168 patients were randomized to receive either hypofractionated (62 Gy in 20 fractions within 5 weeks, 4 fractions/wk) or conventionally fractionated (80 Gy in 40 fractions within 8 weeks) three-dimensional conformal radiotherapy to the prostate and seminal vesicles. All patients had undergone a 9-month course of total androgen deprivation, with radiotherapy starting 2 months after initiation of the total androgen deprivation. Results: The median follow-up was 32 and 35 months in the hypofractionation and conventional fractionation arms, respectively. For the patients developing acute toxicity, no difference between the two fractionation groups was found in either severity or duration of gastrointestinal or genitourinary toxicity. Also, no difference was found in the incidence and severity of late gastrointestinal and genitourinary toxicity between the two treatment schedules, with a 3-year rate of Grade 2 or greater toxicity of 17% and 16% for the hypofractionation arm and 14% and 11% for the conventional fractionation arm, respectively. A statistically significant correlation between acute and late gastrointestinal toxicity was found only in the conventional fractionation group. Conclusion: Our findings suggest that the hypofractionation regimen used in our study is safe, with only a slight, nonsignificant increase in tolerable and temporary acute toxicity compared with the conventional fractionation schedule. The severity and frequency of late complications was equivalent between the two treatment groups.

  19. Two-dimensional pencil beam scaling: an improved proton dose algorithm for heterogeneous media

    International Nuclear Information System (INIS)

    Szymanowski, Hanitra; Oelfke, Uwe

    2002-01-01

    New dose delivery techniques with proton beams, such as beam spot scanning or raster scanning, require fast and accurate dose algorithms which can be applied for treatment plan optimization in clinically acceptable timescales. The clinically required accuracy is particularly difficult to achieve for the irradiation of complex, heterogeneous regions of the patient's anatomy. Currently applied fast pencil beam dose calculations based on the standard inhomogeneity correction of pathlength scaling often cannot provide the accuracy required for clinically acceptable dose distributions. This could be achieved with sophisticated Monte Carlo simulations which are still unacceptably time consuming for use as dose engines in optimization calculations. We therefore present a new algorithm for proton dose calculations which aims to resolve the inherent problem between calculation speed and required clinical accuracy. First, a detailed derivation of the new concept, which is based on an additional scaling of the lateral proton fluence is provided. Then, the newly devised two-dimensional (2D) scaling method is tested for various geometries of different phantom materials. These include standard biological tissues such as bone, muscle and fat as well as air. A detailed comparison of the new 2D pencil beam scaling with the current standard pencil beam approach and Monte Carlo simulations, performed with GEANT, is presented. It was found that the new concept proposed allows calculation of absorbed dose with an accuracy almost equal to that achievable with Monte Carlo simulations while requiring only modestly increased calculation times in comparison to the standard pencil beam approach. It is believed that this new proton dose algorithm has the potential to significantly improve the treatment planning outcome for many clinical cases encountered in highly conformal proton therapy. (author)

  20. Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

    Energy Technology Data Exchange (ETDEWEB)

    Ono, Ichiro; Ohura, Takehiko; Kimura, Chu (Hokkaido Univ., Sapporo (Japan). School of Medicine) (and others)

    1989-08-01

    Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.).

  1. Three-dimensional analysis of craniofacial bones using three-dimensional computer tomography

    International Nuclear Information System (INIS)

    Ono, Ichiro; Ohura, Takehiko; Kimura, Chu

    1989-01-01

    Three-dimensional computer tomography (3DCT) was performed in patients with various diseases to visualize stereoscopically the deformity of the craniofacial bones. The data obtained were analyzed by the 3DCT analyzing system. A new coordinate system was established using the median sagittal plane of the face (a plane passing through sella, nasion and basion) on the three-dimensional image. Three-dimensional profilograms were prepared for detailed analysis of the deformation of craniofacial bones for cleft lip and palate, mandibular prognathia and hemifacial microsomia. For patients, asymmetry in the frontal view and twist-formed complicated deformities were observed, as well as deformity of profiles in the anteroposterior and up-and-down directions. A newly developed technique allows three-dimensional visualization of changes in craniofacial deformity. It would aid in determining surgical strategy, including crani-facial surgery and maxillo-facial surgery, and in evaluating surgical outcome. (N.K.)

  2. Radiotherapy of intensity modulated VS conformational in the treatment of carcinoma of the prostate. A dosimetric comparison; Radioterapia de intensidad modulada VS conformacional en el tratamiento de carcinoma de prostata. Una camparacion dosimetrica

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Martin, G.; Garcia Vicente, F.; Zapatero Laborda, A.; Bermudez Luna, R.; Roch Gonzalez, M.; Perez Gonzalez, L.; Torres Escobar, J. J.

    2013-07-01

    The intensity modulated (IMRT) radiation therapy is a technique of high conformation which, by its nature, has as one of its main directions prostate cancer radiotherapy treatment. The purpose of this work is presents results of the dosimetric indicators collected in our hospital a number of patients of carcinoma of the prostate with standard three-dimensional Conformal technique (3D-CRT) and IMRT. Aims to demonstrate and quantify with a statistical methodology that, establishing an adequate Protocol of IMRT, significant reductions in risk organ doses can be obtained by keeping the same prescription to the white volume. (Author)

  3. High-dose radiation improved local tumor control and overall survival in patients with inoperable/unresectable non-small-cell lung cancer: Long-term results of a radiation dose escalation study

    International Nuclear Information System (INIS)

    Kong, F.-M.; Haken, Randall K. ten; Schipper, Matthew J.; Sullivan, Molly A.; Chen, Ming; Lopez, Carlos; Kalemkerian, Gregory P.; Hayman, James A.

    2005-01-01

    Purpose: To determine whether high-dose radiation leads to improved outcomes in patients with non-small-cell lung cancer (NSCLC). Methods and Materials: This analysis included 106 patients with newly diagnosed or recurrent Stages I-III NSCLC, treated with 63-103 Gy in 2.1-Gy fractions, using three-dimensional conformal radiation therapy (3D-CRT) per a dose escalation trial. Targets included the primary tumor and any lymph nodes ≥1 cm, without intentionally including negative nodal regions. Nineteen percent of patients (20/106) received neoadjuvant chemotherapy. Patient, tumor, and treatment factors were evaluated for association with outcomes. Estimated median follow-up was 8.5 years. Results: Median survival was 19 months, and 5-year overall survival (OS) was 13%. Multivariate analysis revealed weight loss (p = 0.011) and radiation dose (p = 0.0006) were significant predictors for OS. The 5-year OS was 4%, 22%, and 28% for patients receiving 63-69, 74-84, and 92-103 Gy, respectively. Although presence of nodal disease was negatively associated with locoregional control under univariate analysis, radiation dose was the only significant predictor when multiple variables were included (p = 0.015). The 5-year control rate was 12%, 35%, and 49% for 63-69, 74-84, and 92-103 Gy, respectively. Conclusions: Higher dose radiation is associated with improved outcomes in patients with NSCLC treated in the range of 63-103 Gy

  4. High-resolution non-destructive three-dimensional imaging of integrated circuits.

    Science.gov (United States)

    Holler, Mirko; Guizar-Sicairos, Manuel; Tsai, Esther H R; Dinapoli, Roberto; Müller, Elisabeth; Bunk, Oliver; Raabe, Jörg; Aeppli, Gabriel

    2017-03-15

    Modern nanoelectronics has advanced to a point at which it is impossible to image entire devices and their interconnections non-destructively because of their small feature sizes and the complex three-dimensional structures resulting from their integration on a chip. This metrology gap implies a lack of direct feedback between design and manufacturing processes, and hampers quality control during production, shipment and use. Here we demonstrate that X-ray ptychography-a high-resolution coherent diffractive imaging technique-can create three-dimensional images of integrated circuits of known and unknown designs with a lateral resolution in all directions down to 14.6 nanometres. We obtained detailed device geometries and corresponding elemental maps, and show how the devices are integrated with each other to form the chip. Our experiments represent a major advance in chip inspection and reverse engineering over the traditional destructive electron microscopy and ion milling techniques. Foreseeable developments in X-ray sources, optics and detectors, as well as adoption of an instrument geometry optimized for planar rather than cylindrical samples, could lead to a thousand-fold increase in efficiency, with concomitant reductions in scan times and voxel sizes.

  5. High-resolution non-destructive three-dimensional imaging of integrated circuits

    Science.gov (United States)

    Holler, Mirko; Guizar-Sicairos, Manuel; Tsai, Esther H. R.; Dinapoli, Roberto; Müller, Elisabeth; Bunk, Oliver; Raabe, Jörg; Aeppli, Gabriel

    2017-03-01

    Modern nanoelectronics has advanced to a point at which it is impossible to image entire devices and their interconnections non-destructively because of their small feature sizes and the complex three-dimensional structures resulting from their integration on a chip. This metrology gap implies a lack of direct feedback between design and manufacturing processes, and hampers quality control during production, shipment and use. Here we demonstrate that X-ray ptychography—a high-resolution coherent diffractive imaging technique—can create three-dimensional images of integrated circuits of known and unknown designs with a lateral resolution in all directions down to 14.6 nanometres. We obtained detailed device geometries and corresponding elemental maps, and show how the devices are integrated with each other to form the chip. Our experiments represent a major advance in chip inspection and reverse engineering over the traditional destructive electron microscopy and ion milling techniques. Foreseeable developments in X-ray sources, optics and detectors, as well as adoption of an instrument geometry optimized for planar rather than cylindrical samples, could lead to a thousand-fold increase in efficiency, with concomitant reductions in scan times and voxel sizes.

  6. Topics in low-dimensional field theory

    International Nuclear Information System (INIS)

    Crescimanno, M.J.

    1991-01-01

    Conformal field theory is a natural tool for understanding two- dimensional critical systems. This work presents results in the lagrangian approach to conformal field theory. The first sections are chiefly about a particular class of field theories called coset constructions and the last part is an exposition of the connection between two-dimensional conformal theory and a three-dimensional gauge theory whose lagrangian is the Chern-Simons density

  7. The intercomparison of the dose distributions between conformation techniques with pions and photons

    International Nuclear Information System (INIS)

    Karasawa, K.; Nakagawa, K.; Akanuma, A.

    1990-01-01

    To compare conformation radiation treatment with pions vs photons, dose volume histograms (DVH) to the critical organs, including the spinal cord, kidney, and intestine, were examined in a patient with retroperitoneal soft tissue sarcoma. For photon conformation treatment, the following techniques were used: 360 degree rotation conformation technique (photon conformation), 4 fixed field technique (photon 4-field), and 2-axis conformation technique (photon 2-axial conformation). According to the DVH reduction method, complication probability was estimated. The concave portion of the target was conformed by pion conformation treatment, but not by photon conformation treatment. Pion conformation for the intestine showed the best DVH, whereas photon 4-field technique showed the worst DVH. For the kidney, pion conformation showed better DVH as compared with any other photon conformation treatment technique. In the spinal cord, photon 2-axial conformation was far superior, followed by pion conformation and then photon conformation and 4-field technique. A 2-axial technique showed a bigger inhomogeneity inside the target volume which is critical in curative treatment. TD 50 was 72 Gy for pion conformation, 53 Gy for photon conformation, 51 Gy for photon 4-field, and 68 Gy for photon 2-axial conformation. Complication probabilities for these conformation techniques at 60 Gy were 3%, 85%, 97%, and 9%. In view of tumor control probabilities, pion seems to have the biggest therapeutic ratio among these techniques. (N.K.)

  8. The ''three-dimensional time'' equation

    International Nuclear Information System (INIS)

    Pappas, P.T.; Athens Univ.

    1979-01-01

    The connection of the proper time between two observers is found within the six dimensional formalism. Small quantitative differences emerge from the GLT-combinations of rotations and SLT-boosts, but not from the SLT alone. It is also shown how to embed R 4 into R 6 . Transforming R 6 , transformations of R 4 arise which leave C constant and conform to a natural definition of ''parallelism'' -given. (author)

  9. Three dimensional strained semiconductors

    Science.gov (United States)

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

    2016-11-08

    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  10. A method to combine three dimensional dose distributions for external beam and brachytherapy radiation treatments for gynecological neoplasms

    International Nuclear Information System (INIS)

    Narayana, V.; Sahijdak, W.M.; Orton, C.G.

    1997-01-01

    Purpose: Radiation treatment of gynecological neoplasms, such as cervical carcinoma, usually combines external radiation therapy with one or more intracavitary brachytherapy applications. Although the dose from external beam radiation therapy and brachytherapy can be calculated and displayed in 3D individually, the dose distributions are not combined. At most, combined point doses are calculated for select points using various time-dose models. In this study, we present a methodology to combine external beam and brachytherapy treatments for gynecological neoplasms. Material and Methods: Three dimensional bio-effect treatment planning to obtain complication probability has been outlined. CT scans of the patient's pelvis with the gynecological applicator in place are used to outline normal tissue and tumor volumes. 3D external beam and brachytherapy treatment plans are developed separately and an external beam dose matrix and a brachytherapy dose matrix was calculated. The dose in each voxel was assumed to be homogeneous. The physical dose in each voxel of the dose matrix was then converted into extrapolated response dose (ERD) based on the linear quadratic model that accounts for the dose per fraction, number of fractions, dose rate, and complete or incomplete repair of sublethal damage (time between fractions). The net biological dose delivered was obtained by summing the ERD grids from external beam and brachytherapy since there was complete repair of sublethal damage between external beam and brachytherapy treatments. The normal tissue complication probability and tumor control probability were obtained using the biological dose matrix based on the critical element model. Results: The outlined method of combining external beam and brachytherapy treatments was implemented on gynecological treatments using an applicator for brachytherapy treatments. Conclusion: Implementation of the biological dose calculation that combine different modalities is extremely useful

  11. Long-Term Outcomes After High-Dose Postprostatectomy Salvage Radiation Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Goenka, Anuj; Magsanoc, Juan Martin; Pei Xin; Schechter, Michael; Kollmeier, Marisa; Cox, Brett [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Scardino, Peter T.; Eastham, James A. [Urology Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Zelefsky, Michael J., E-mail: zelefskm@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2012-09-01

    Purpose: To review the impact of high-dose radiotherapy (RT) in the postprostatectomy salvage setting on long-term biochemical control and distant metastases-free survival, and to identify clinical and pathologic predictors of outcomes. Methods and Materials: During 1988-2007, 285 consecutive patients were treated with salvage RT (SRT) after radical prostatectomy. All patients were treated with either three-dimensional conformal RT or intensity-modulated RT. Two hundred seventy patients (95%) were treated to a dose {>=}66 Gy, of whom 205 (72%) received doses {>=}70 Gy. Eighty-seven patients (31%) received androgen-deprivation therapy as a component of their salvage treatment. All clinical and pathologic records were reviewed to identify treatment risk factors and response. Results: The median follow-up time after SRT was 60 months. Seven-year actuarial prostate-specific antigen (PSA) relapse-free survival and distant metastases-free survival were 37% and 77%, respectively. Independent predictors of biochemical recurrence were vascular invasion (p < 0.01), negative surgical margins (p < 0.01), presalvage PSA level >0.4 ng/mL (p < 0.01), androgen-deprivation therapy (p = 0.03), Gleason score {>=}7 (p = 0.02), and seminal vesicle involvement (p = 0.05). Salvage RT dose {>=}70 Gy was not associated with improvement in biochemical control. A doubling time <3 months was the only independent predictor of metastatic disease (p < 0.01). There was a trend suggesting benefit of SRT dose {>=}70 Gy in preventing clinical local failure in patients with radiographically visible local disease at time of SRT (7 years: 90% vs. 79.1%, p = 0.07). Conclusion: Salvage RT provides effective long-term biochemical control and freedom from metastasis in selected patients presenting with detectable PSA after prostatectomy. Androgen-deprivation therapy was associated with improvement in biochemical progression-free survival. Clinical local failures were rare but occurred most commonly in

  12. Synergies Between ' and Cavity Formation in HT-9 Following High Dose Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Field, Kevin G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Parish, Chad M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Saleh, Tarik A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Eftink, Benjamin P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    Candidate cladding materials for advanced nuclear power reactors including fast reactor designs require materials capable of withstanding high dose neutron irradiation at elevated temperatures. One candidate material, HT-9, through various research programs have demonstrated the ability to withstand significant swelling and other radiation-induced degradation mechanisms in the high dose regime (>50 displacements per atom, dpa) at elevated temperatures (>300 C). Here, high efficiency multi-dimensional scanning transmission electron microscopy (STEM) acquisition with the aid of a three-dimensional (3D) reconstruction and modeling technique is used to probe the microstructural features that contribute to the exceptional swelling resistance of HT-9. In particular, the synergies between ' and fine-scale and moderate-scale cavity formation is investigated.

  13. Volume scanning three-dimensional display with an inclined two-dimensional display and a mirror scanner

    Science.gov (United States)

    Miyazaki, Daisuke; Kawanishi, Tsuyoshi; Nishimura, Yasuhiro; Matsushita, Kenji

    2001-11-01

    A new three-dimensional display system based on a volume-scanning method is demonstrated. To form a three-dimensional real image, an inclined two-dimensional image is rapidly moved with a mirror scanner while the cross-section patterns of a three-dimensional object are displayed sequentially. A vector-scan CRT display unit is used to obtain a high-resolution image. An optical scanning system is constructed with concave mirrors and a galvanometer mirror. It is confirmed that three-dimensional images, formed by the experimental system, satisfy all the criteria for human stereoscopic vision.

  14. Extensions of conformal symmetry in two-dimensional quantum field theory

    International Nuclear Information System (INIS)

    Schoutens, C.J.M.

    1989-01-01

    Conformal symmetry extensions in a two-dimensional quantum field theory are the main theme of the work presented in this thesis. After a brief exposition of the formalism for conformal field theory, the motivation for studying extended symmetries in conformal field theory is presented in some detail. Supersymmetric extensions of conformal symmetry are introduced. An overview of the algebraic superconformal symmetry is given. The relevance of higher-spin bosonic extensions of the Virasoro algebra in relation to the classification program for so-called rational conformal theories is explained. The construction of a large class of bosonic extended algebras, the so-called Casimir algebras, are presented. The representation theory of these algebras is discussed and a large class of new unitary models is identified. The superspace formalism for O(N)-extended superconformal quantum field theory is presented. It is shown that such theories exist for N ≤ 4. Special attention is paid to the case N = 4 and it is shown that the allowed central charges are c(n + ,n - ) = 6n + n - /(n + ,n - ), where n + and n - are positive integers. A different class of so(N)-extended superconformal algebras is analyzed. The representation theory is studied and it is established that certain free field theories provide realizations of the algebras with level S = 1. Finally the so-called BRST construction for extended conformal algebras is considered. A nilpotent BRST charge is constructed for a large class of algebras, which contains quadratically nonlinear algebras that fall outside the traditional class if finitely generated Lie (super)algebras. The results are especially relevant for the construction of string models based on extended conformal symmetry. (author). 118 refs.; 7 tabs

  15. Field in field technique in two-dimensional planning for whole brain irradiation; Tecnica field in field em planejamentos bidimensionais para irradiacao de cerebro total

    Energy Technology Data Exchange (ETDEWEB)

    Castro, A.L.S.; Campos, T.P.R., E-mail: radioterapia.andre@gmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil). Departamento de Engenharia Nuclear

    2016-11-01

    Radiotherapy is the most used clinical method used for brain metastases treatment, the most frequent secondary tumors provided by breast, lung and melanomas as primary origin. The protocols often use high daily doses and, depending on the irradiation technique there is high probability of complications in health tissues. In order to minimize adverse effects, it is important the dosimetric analysis of three-dimensional radiotherapy planning through tomographic images or, concerning to the 2D simulations, by the application of techniques that optimize dose distribution by increasing the homogeneity. The study aimed to compare the 2D and 3D conformal planning for total brain irradiation in a individual equivalent situation and evaluate the progress of these planning applying the field in field technique. The methodology consisted of simulating a two-dimensional planning, reproduce it on a set of tomographic images and compare it with the conformal plan for two fields and four fields (field in field). The results showed no significant difference between 2D and 3D planning for whole brain irradiation, and the field in field technique significantly improved the dose distribution in brain volume compared with two fields for the proposal situation. As conclusion, the two-dimensional plane for the four fields described was viable for whole brain irradiation in the treatment of brain metastases at the proposal situation. (author)

  16. On the use of multi-dimensional scaling and electromagnetic tracking in high dose rate brachytherapy

    Science.gov (United States)

    Götz, Th I.; Ermer, M.; Salas-González, D.; Kellermeier, M.; Strnad, V.; Bert, Ch; Hensel, B.; Tomé, A. M.; Lang, E. W.

    2017-10-01

    High dose rate brachytherapy affords a frequent reassurance of the precise dwell positions of the radiation source. The current investigation proposes a multi-dimensional scaling transformation of both data sets to estimate dwell positions without any external reference. Furthermore, the related distributions of dwell positions are characterized by uni—or bi—modal heavy—tailed distributions. The latter are well represented by α—stable distributions. The newly proposed data analysis provides dwell position deviations with high accuracy, and, furthermore, offers a convenient visualization of the actual shapes of the catheters which guide the radiation source during the treatment.

  17. 3-D conformal treatment of prostate cancer to 74 Gy vs. high-dose-rate brachytherapy boost: A cross-sectional quality-of-life survey

    Energy Technology Data Exchange (ETDEWEB)

    Vordermark, Dirk [Univ. of Wuerzburg (DE). Dept. of Radiation Oncology] (and others)

    2006-09-15

    The effects of two modalities of dose-escalated radiotherapy on health-related quality of life (HRQOL) were compared. Forty-one consecutive patients were treated with a 3-D conformal (3-DC) boost to 74 Gy, and 43 with high-dose rate (HDR) brachytherapy boost (2x9 Gy), following 3-D conformal treatment to 46 Gy. Median age was 70 years in both groups, median initial PSA was 7.9 {mu}g/l in 3-DC boost patients and 8.1 {mu}g/l in HDR boost patients. Stage was 7 in 52% and 47%, respectively. HRQOL was assessed cross-sectionally using EORTC QLQ-C30 and organ-specific PR25 modules 3-32 (median 19) and 4-25 (median 14) months after treatment, respectively. Questionnaires were completed by 93% and 97% of patients, respectively. Diarrhea and insomnia scores were significantly increased in both groups. In the PR25 module, scores of 3-DC boost and HDR boost patients for urinary, bowel and treatment-related symptoms were similar. Among responders, 34% of 3-DC boost patients and 86% of HDR boost patients had severe erectile problems. Dose escalation in prostate cancer by either 3-DC boost to 74 Gy or HDR brachytherapy boost appears to result in similar HRQOL profiles.

  18. Nonrelativistic Conformed Symmetry in 2 + 1 Dimensional Field Theory.

    Science.gov (United States)

    Bergman, Oren

    This thesis is devoted to the study of conformal invariance and its breaking in non-relativistic field theories. It is a well known feature of relativistic field theory that theories which are conformally invariant at the classical level can acquire a conformal anomaly upon quantization and renormalization. The anomaly appears through the introduction of an arbitrary, but dimensionful, renormalization scale. One does not usually associate the concepts of renormalization and anomaly with nonrelativistic quantum mechanics, but there are a few examples where these concepts are useful. The most well known case is the two-dimensional delta -function potential. In two dimensions the delta-function scales like the kinetic term of the Hamiltonian, and therefore the problem is classically conformally invariant. Another example of classical conformal invariance is the famous Aharonov-Bohm (AB) problem. In that case each partial wave sees a 1/r^2 potential. We use the second quantized formulation of these problems, namely the nonrelativistic field theories, to compute Green's functions and derive the conformal anomaly. In the case of the AB problem we also solve an old puzzle, namely how to reproduce the result of Aharonov and Bohm in perturbation theory. The thesis is organized in the following manner. Chapter 1 is an introduction to nonrelativistic field theory, nonrelativistic conformal invariance, contact interactions and the AB problem. In Chapter 2 we discuss nonrelativistic scalar field theory, and how its quantization produces the anomaly. Chapter 3 is devoted to the AB problem, and the resolution of the perturbation puzzle. In Chapter 4 we generalize the discussion of Chapter 3 to particles carrying nonabelian charges. The structure of the nonabelian theory is much richer, and deserves a separate discussion. We also comment on the issues of forward scattering and single -valuedness of wavefunctions, which are important for Chapter 3 as well. (Copies available

  19. Late radiation side effects, cosmetic outcomes and pain in breast cancer patients after breast-conserving surgery and three-dimensional conformal radiotherapy. Risk-modifying factors

    International Nuclear Information System (INIS)

    Hille-Betz, Ursula; Soergel, Philipp; Kundu, Sudip; Klapdor, Ruediger; Hillemanns, Peter; Vaske, Bernhard; Bremer, Michael; Henkenberens, Christoph

    2016-01-01

    The purpose of this work was to identify parameters influencing the risk of late radiation side effects, fair or poor cosmetic outcomes (COs) and pain in breast cancer patients after breast-conserving therapy (BCT) and three-dimensional conformal radiotherapy (3D-CRT). Between 2006 and 2013, 159 patients were treated at the Hannover Medical School. Physician-rated toxicity according to the LENT-SOMA criteria, CO and pain were assessed by multivariate analysis. LENT-SOMA grade 1-4 toxicity was observed as follows: fibrosis 10.7 %, telangiectasia 1.2 %, arm oedema 8.8 % and breast oedema 5.0 %. In addition, 15.1 % of patients reported moderate or severe breast pain, and 21.4 % complained about moderate or severe pain in the arm or shoulder. In multivariate analysis, axillary clearing (AC) was significantly associated with lymphoedema of the arm [odds ratio (OR) 4.37, p = 0.011, 95 % confidence interval (CI) 1.4-13.58]. Breast oedema was also highly associated with AC (OR 10.59, p = 0.004, 95 % CI 2.1-53.36), a ptosis grade 2/3 or pseudoptosis and a bra size ≥ cup C (OR 5.34, p = 0.029, 95 % CI 1.2-24.12). A ptosis grade 2/3 or pseudoptosis and a bra size ≥ cup C were the parameters significantly associated with an unfavourable CO (OR 3.19, p = 0.019, 95 % CI 1.2-8.4). Concerning chronic breast pain, we found a trend related to the prescribed radiation dose including boost (OR 1.077, p = 0.060, 95 % CI 0.997-1.164). Chronic shoulder or arm pain was statistically significantly associated with lymphoedema of the arm (OR 3.9, p = 0.027, 95 % CI 1.17-13.5). Chronic arm and breast oedema were significantly influenced by the extent of surgery (AC). Ptotic and large breasts were significantly associated with unfavourable COs and chronic breast oedema. Late toxicities exclusive breast pain were not associated with radiotherapy parameters. (orig.) [de

  20. MRI definition of target volumes using fuzzy logic method for three-dimensional conformal radiation therapy

    International Nuclear Information System (INIS)

    Caudrelier, Jean-Michel; Vial, Stephane; Gibon, David; Kulik, Carine; Fournier, Charles; Castelain, Bernard; Coche-Dequeant, Bernard; Rousseau, Jean

    2003-01-01

    Purpose: Three-dimensional (3D) volume determination is one of the most important problems in conformal radiation therapy. Techniques of volume determination from tomographic medical imaging are usually based on two-dimensional (2D) contour definition with the result dependent on the segmentation method used, as well as on the user's manual procedure. The goal of this work is to describe and evaluate a new method that reduces the inaccuracies generally observed in the 2D contour definition and 3D volume reconstruction process. Methods and Materials: This new method has been developed by integrating the fuzziness in the 3D volume definition. It first defines semiautomatically a minimal 2D contour on each slice that definitely contains the volume and a maximal 2D contour that definitely does not contain the volume. The fuzziness region in between is processed using possibility functions in possibility theory. A volume of voxels, including the membership degree to the target volume, is then created on each slice axis, taking into account the slice position and slice profile. A resulting fuzzy volume is obtained after data fusion between multiorientation slices. Different studies have been designed to evaluate and compare this new method of target volume reconstruction and a classical reconstruction method. First, target definition accuracy and robustness were studied on phantom targets. Second, intra- and interobserver variations were studied on radiosurgery clinical cases. Results: The absolute volume errors are less than or equal to 1.5% for phantom volumes calculated by the fuzzy logic method, whereas the values obtained with the classical method are much larger than the actual volumes (absolute volume errors up to 72%). With increasing MRI slice thickness (1 mm to 8 mm), the phantom volumes calculated by the classical method are increasing exponentially with a maximum absolute error up to 300%. In contrast, the absolute volume errors are less than 12% for phantom

  1. Simulating three-dimensional nonthermal high-energy photon emission in colliding-wind binaries

    Energy Technology Data Exchange (ETDEWEB)

    Reitberger, K.; Kissmann, R.; Reimer, A.; Reimer, O., E-mail: klaus.reitberger@uibk.ac.at [Institut für Astro- und Teilchenphysik and Institut für Theoretische Physik, Leopold-Franzens-Universität Innsbruck, A-6020 Innsbruck (Austria)

    2014-07-01

    Massive stars in binary systems have long been regarded as potential sources of high-energy γ rays. The emission is principally thought to arise in the region where the stellar winds collide and accelerate relativistic particles which subsequently emit γ rays. On the basis of a three-dimensional distribution function of high-energy particles in the wind collision region—as obtained by a numerical hydrodynamics and particle transport model—we present the computation of the three-dimensional nonthermal photon emission for a given line of sight. Anisotropic inverse Compton emission is modeled using the target radiation field of both stars. Photons from relativistic bremsstrahlung and neutral pion decay are computed on the basis of local wind plasma densities. We also consider photon-photon opacity effects due to the dense radiation fields of the stars. Results are shown for different stellar separations of a given binary system comprising of a B star and a Wolf-Rayet star. The influence of orbital orientation with respect to the line of sight is also studied by using different orbital viewing angles. For the chosen electron-proton injection ratio of 10{sup –2}, we present the ensuing photon emission in terms of two-dimensional projections maps, spectral energy distributions, and integrated photon flux values in various energy bands. Here, we find a transition from hadron-dominated to lepton-dominated high-energy emission with increasing stellar separations. In addition, we confirm findings from previous analytic modeling that the spectral energy distribution varies significantly with orbital orientation.

  2. Three-dimensional conformal radiotherapy by delineations on CT-based simulation in different respiratory phases for the treatment of senile patients with non-small cell lung cancer.

    Science.gov (United States)

    Wang, Weifeng; Yuan, Feng; Wang, Guoping; Lin, Zhiren; Pan, Yanling; Chen, Longhua

    2015-01-01

    This study aimed to evaluate the application of three-dimensional conformal radiotherapy (3D-CRT) for elderly patients with non-small cell lung cancer (NSCLC) based on computed tomography (CT) simulations in different respiratory phases. A total of 64 patients aged >70 years old with NSCLC were treated by 3D-CRT using CT images in different respiratory phases. The gross tumor volumes (GTVs) at the end of inspiration and end of expiration were combined to obtain the total GTV, which was close to the motional range of tumors during respiration, and no additional expansion of the clinical target volume (CTAV) to planning target volume (PTV) (CTAV:PTV) was included during the recording of respiratory movements. Patients were also planned according to the classic 3D-CRT approach. Efficacy, prognostic factors, and side effects were evaluated. Compared with the classic approach, the average PTV was 18.9% lower (median: 17.3%), and the average lung volume receiving a prescribed dose for a tumor was 22.4% lower (median: 20.9%). The 1-, 2-, and 3-year survival rates were 70.6%, 54.9%, and 29.4%, respectively, with an overall tumor response rate of 79.7%. The Karnofsky performance status and N stage were independent prognostic factors, whereas age was not. Without affecting therapeutic effects, CT simulations in different respiratory phases were well-tolerated in elderly patients with NSCLC, could effectively reduce PTV, and could improve the quality of life.

  3. Variation of clinical target volume definition in three-dimensional conformal radiation therapy for prostate cancer

    International Nuclear Information System (INIS)

    Valicenti, Richard K.; Sweet, John W.; Hauck, Walter W.; Hudes, Richard S.; Lee, Tony; Dicker, Adam P.; Waterman, Frank M.; Anne, Pramila R.; Corn, Benjamin W.; Galvin, James M.

    1999-01-01

    Purpose: Currently, three-dimensional conformal radiation therapy (3D-CRT) planning relies on the interpretation of computed tomography (CT) axial images for defining the clinical target volume (CTV). This study investigates the variation among multiple observers to define the CTV used in 3D-CRT for prostate cancer. Methods and Materials: Seven observers independently delineated the CTVs (prostate ± seminal vesicles [SV]) from the CT simulation data of 10 prostate cancer patients undergoing 3D-CRT. Six patients underwent CT simulation without the use of contrast material and serve as a control group. The other 4 had urethral and bladder opacification with contrast medium. To determine interobserver variation, we evaluated the derived volume, the maximum dimensions, and the isocenter for each examination of CTV. We assessed the reliability in the CTVs among the observers by correlating the variation for each class of measurements. This was estimated by intraclass correlation coefficient (ICC), with 1.00 defining absolute correlation. Results: For the prostate volumes, the ICC was 0.80 (95% confidence interval [CI]: 0.56-0.96). This changed to 0.92 (95% CI: 0.75-0.99) with the use of contrast material. Similarly, the maximal prostatic dimensions were reliable and improved. There was poor agreement in defining the SV. For this structure, the ICC never exceeded 0.28. The reliability of the isocenter was excellent, with the ICC exceeding 0.83 and 0.90 for the prostate ± SV, respectively. Conclusions: In 3D-CRT for prostate cancer, there was excellent agreement among multiple observers to define the prostate target volume but poor agreement to define the SV. The use of urethral and bladder contrast improved the reliability of localizing the prostate. For all CTVs, the isocenter was very reliable and should be used to compare the variation in 3D dosimetry among multiple observers

  4. The role of three-dimensional high-definition laparoscopic surgery for gynaecology.

    Science.gov (United States)

    Usta, Taner A; Gundogdu, Elif C

    2015-08-01

    This article reviews the potential benefits and disadvantages of new three-dimensional (3D) high-definition laparoscopic surgery for gynaecology. With the new-generation 3D high-definition laparoscopic vision systems (LVSs), operation time and learning period are reduced and procedural error margin is decreased. New-generation 3D high-definition LVSs enable to reduce operation time both for novice and experienced surgeons. Headache, eye fatigue or nausea reported with first-generation systems are not different than two-dimensional (2D) LVSs. The system's being more expensive, having the obligation to wear glasses, big and heavy camera probe in some of the devices are accounted for negative aspects of the system that need to be improved. Depth loss in tissues in 2D LVSs and associated adverse events can be eliminated with 3D high-definition LVSs. By virtue of faster learning curve, shorter operation time, reduced error margin and lack of side-effects reported by surgeons with first-generation systems, 3D LVSs seem to be a strong competition to classical laparoscopic imaging systems. Thanks to technological advancements, using lighter and smaller cameras and monitors without glasses is in the near future.

  5. Animation and radiobiological analysis of 3D motion in conformal radiotherapy.

    Science.gov (United States)

    MacKay, R I; Graham, P A; Moore, C J; Logue, J P; Sharrock, P J

    1999-07-01

    To allow treatment plans to be evaluated against the range of expected organ motion and set up error anticipated during treatment. Planning tools have been developed to allow concurrent animation and radiobiological analysis of three dimensional (3D) target and organ motion in conformal radiotherapy. Surfaces fitted to structures outlined on CT studies are projected onto pre-treatment images or onto megavoltage images collected during the patient treatment. Visual simulation of tumour and normal tissue movement is then performed by the application of three dimensional affine transformations, to the selected surface. Concurrent registration of the surface motion with the 3D dose distribution allows calculation of the change in dose to the volume. Realistic patterns of motion can be applied to the structure to simulate inter-fraction motion and set-up error. The biologically effective dose for the structure is calculated for each fraction as the surface moves over the course of the treatment and is used to calculate the normal tissue complication probability (NTCP) or tumour control probability (TCP) for the moving structure. The tool has been used to evaluate conformal therapy plans against set up measurements recorded during patient treatments. NTCP and TCP were calculated for a patient whose set up had been corrected after systematic deviations from plan geometry were measured during treatment, the effect of not making the correction were also assessed. TCP for the moving tumour was reduced if inadequate margins were set for the treatment. Modelling suggests that smaller margins could have been set for the set up corrected during the course of the treatment. The NTCP for the rectum was also higher for the uncorrected set up due to a more rectal tissue falling in the high dose region. This approach provides a simple way for clinical users to utilise information incrementally collected throughout the whole of a patient's treatment. In particular it is possible to

  6. A geometrical approach to two-dimensional Conformal Field Theory

    Science.gov (United States)

    Dijkgraaf, Robertus Henricus

    1989-09-01

    manifold obtained as the quotient of a smooth manifold by a discrete group. In Chapter 6 our considerations will be of a somewhat complementary nature. We will investigate models with central charge c = 1 by deformation techniques. The central charge is a fundamental parameter in any conformal invariant model, and the value c = 1 is of considerable interest, since it forms in many ways a threshold value. For c 1 is still very much terra incognita. Our results give a partial classification for the intermediate case of c = 1 models. The formulation of these c = 1 CFT's on surfaces of arbitrary topology is central in Chapter 7. Here we will provide many explicit results that provide illustrations for our more abstract discussions of higher genus quantities in Chapters 3 and 1. Unfortunately, our calculations will become at this point rather technical, since we have to make extensive use of the mathematics of Riemann surfaces and their coverings. Finally, in Chapter 8 we leave the two-dimensional point of view that we have been so loyal to up to then , and ascend to threedimensions where we meet topological gauge theories. These so-called Chern-Simons theories encode in a very economic way much of the structure of two-dimensional (rational) conformal field theories, and this direction is generally seen to be very promising. We will show in particular how many of our results of Chapter 5 have a natural interpretation in three dimensions.

  7. Preparation of three-dimensional graphene foam for high performance supercapacitors

    Directory of Open Access Journals (Sweden)

    Yunjie Ping

    2017-04-01

    Full Text Available Supercapacitor is a new type of energy-storage device, and has been attracted widely attentions. As a two dimensional (2D nanomaterials, graphene is considered to be a promising material of supercapacitor because of its excellent properties involving high electrical conductivity and large surface area. In this paper, the large-scale graphene is successfully fabricated via environmental-friendly electrochemical exfoliation of graphite, and then, the three dimensional (3D graphene foam is prepared by using nickel foam as template and FeCl3/HCl solution as etchant. Compared with the regular 2D graphene paper, the 3D graphene foam electrode shows better electrochemical performance, and exhibits the largest specific capacitance of approximately 128 F/g at the current density of 1 A/g in 6 M KOH electrolyte. It is expected that the 3D graphene foam will have a potential application in the supercapacitors.

  8. Polycrystalline diamond detectors with three-dimensional electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Lagomarsino, S., E-mail: lagomarsino@fi.infn.it [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Bellini, M. [INO-CNR Firenze, Largo E. Fermi 6, 50125 Firenze (Italy); Brianzi, M. [INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Carzino, R. [Smart Materials-Nanophysics, Istituto Italiano di Tecnologia, Genova, Via Morego 30, 16163 Genova (Italy); Cindro, V. [Joseph Stefan Institute, Jamova Cesta 39, 1000 Ljubljana (Slovenia); Corsi, C. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); LENS Firenze, Via N. Carrara 1, 50019 Sesto Fiorentino (Italy); Morozzi, A.; Passeri, D. [INFN Perugia, Perugia (Italy); Università degli Studi di Perugia, Dipartimento di Ingegneria, via G. Duranti 93, 06125 Perugia (Italy); Sciortino, S. [University of Florence, Department of Physics, Via Sansone 1, 50019 Sesto Fiorentino (Italy); INFN Firenze, Via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Servoli, L. [INFN Perugia, Perugia (Italy)

    2015-10-01

    The three-dimensional concept in diamond detectors has been applied, so far, to high quality single-crystal material, in order to test this technology in the best available conditions. However, its application to polycrystalline chemical vapor deposited diamond could be desirable for two reasons: first, the short inter-electrode distance of three-dimensional detectors should improve the intrinsically lower collection efficiency of polycrystalline diamond, and second, at high levels of radiation damage the performances of the poly-crystal material are not expected to be much lower than those of the single crystal one. We report on the fabrication and test of three-dimensional polycrystalline diamond detectors with several inter-electrode distances, and we demonstrate that their collection efficiency is equal or higher than that obtained with conventional planar detectors fabricated with the same material. - Highlights: • Pulsed laser fabrication of polycristalline diamond detectors with 3D electrodes. • Measurement of the charge collection efficiency (CCE) under beta irradiation. • Comparation between the CCE of 3D and conventional planar diamond sensors. • A rationale for the behavior of three-dimensional and planar sensors is given.

  9. Impact of radiation dose on achieving nadir PSA levels after 3-dimensional conformal radiotherapy for patients with localized prostate cancer

    International Nuclear Information System (INIS)

    Zelefsky, Michael J.; Leibel, Steven A.; Kelson, Suzanne; Fuks, Zvi

    1996-01-01

    Purpose: Several reports have documented the prognostic value of a post-irradiation nadir PSA of ≤1 ng/ml in prostatic cancer patients. The purpose of this study was to determine which pre-treatment and treatment-related variables impact upon achieving such nadir levels. Materials and Methods: Between January 1987 and June 1995, 740 patients with clinically localized prostate cancer were treated with 3-dimensional conformal radiotherapy (3D-CRT). 214 (29%) patients were treated with neo-adjuvant androgen ablation prior to therapy and were excluded from this analysis. Among the 526 evaluable patients, the clinical stage were as follows: T 1 C=128 (24%); T 2 A=76 (14%); T 2 B=116 (22%); T 2 C=99 (19%) and T 3 =107 (21%). The prescription dose to the planning target volume (PTV) was 64.8-68.4 Gy in 87 patients (17%); 70.2 Gy in 191 (36%); 75.6 Gy in 209 (40%) and 81 Gy in 39 (7%). The median pre-treatment PSA value was 11.2 ng/ml (range 0.3-114). The median follow-up was 20 months (range: 6-76 months). Results: 242 patients (46%) had PSA levels which declined to ≤1.0 ng/ml. The median time to a nadir level of ≤1.0 was 15.6 months (range: 1-43 months) from completion of 3D-CRT. 154 (29%) patients continued to show declining PSA levels within the first 2 years after therapy, and 130 patients (25%) failed to nadir at PSA levels of ≤1.0 ng/ml. Among patients with nadir PSA levels ≤1, the 3 year PSA relapse-free survival was 91% compared to 29% for patients with nadir PSA levels >1 ng/ml (p<0.0001). A Cox-regression analysis demonstrated that nadir PSA ≤1 was the strongest predictor of PSA relapse-free survival (p<0.001) followed by Gleason score ≤ 6 (p<0.001) and stage< T3 (p=0.004). Among patients who received doses of ≥75.6 Gy, the likelihood of achieving PSA nadir levels ≤1.0 at 24 and 36 months was 86% and 93%, respectively, compared to 74 and 80%, respectively, among those who received lower doses (p<0.001). Doses of ≥75.6 Gy was the strongest

  10. Three-dimensional shear transformation zone dynamics model for amorphous metals

    International Nuclear Information System (INIS)

    Homer, Eric R; Schuh, Christopher A

    2010-01-01

    A fully three-dimensional (3D) mesoscale modeling framework for the mechanical behavior of amorphous metals is proposed. The model considers the coarse-grained action of shear transformation zones (STZs) as the fundamental deformation event. The simulations are controlled through the kinetic Monte Carlo algorithm and the mechanical response of the system is captured through finite-element analysis, where STZs are mapped onto a 3D finite-element mesh and are allowed to shear in any direction in three dimensions. Implementation of the technique in uniaxial creep tests over a wide range of conditions validates the model's ability to capture the expected behaviors of an amorphous metal, including high temperature flow conforming to the expected constitutive law and low temperature localization in the form of a nascent shear band. The simulation results are combined to construct a deformation map that is comparable to experimental deformation maps. The flexibility of the modeling framework is illustrated by performing a contact test (simulated nanoindentation) in which the model deforms through STZ activity in the region experiencing the highest shear stress

  11. High-dose (70-78 GY) conformal radiotherapy for prostate cancer; the relation between observed late bladder and rectum complications and parameters derived from the dose volume histograms

    International Nuclear Information System (INIS)

    Lebesque, J.V.; Bruce, A.; Boersma, L.J.; Velde, A. te

    1996-01-01

    complications (≥ grade II) was 13% at 2 years, both for doses to the anterior rectal wall ≤ 75 Gy and > 75 Gy (Figure). This is much lower than after conventional radiotherapy for prostate cancer (Smit et al.), where these figures were 21% and 60%, respectively. In univariate analyses, we did not find a significant relation between GI complications rates (grade II and/or III) and irradiated rectal wall volumes, total prescribed radiation dose or maximum radiation dose to the anterior rectal wall. The estimated NTCPs (on average 11%) were much higher than the incidence of grade III GI toxicity in our study ( 20% these figures were 11.4% and 0%, respectively. We are currently investigating whether dose surface histograms are more reliable to predict the observed late GI complications ≥ grade II. Conclusions: Conformal radiotherapy reduces late rectal complications significantly with respect to conventional radiotherapy. Observed late GI complications grade III were much lower than the NTCP estimations based on the model and parameter values of Kutcher et al. and Burman et al., respectively. Observed late GI complications ≥ grade II were overall in the range of the NTCP estimations, but did not correlate specifically with DVH parameters and NTCP estimations. Consequently, adaptation of the NTCP model and/or its parameter values for rectum complications is highly necessary. Grade III GU complications were mostly related to the prostatic urethra and consequently DVHs of the bladder have only limited value

  12. Relative entropy of excited states in two dimensional conformal field theories

    Energy Technology Data Exchange (ETDEWEB)

    Sárosi, Gábor [Department of Theoretical Physics, Institute of Physics, Budapest University of Technology,Budapest, H-1521 (Hungary); Ugajin, Tomonori [Kavli Institute for Theoretical Physics, University of California,Santa Barbara,CA 93106 (United States)

    2016-07-21

    We study the relative entropy and the trace square distance, both of which measure the distance between reduced density matrices of two excited states in two dimensional conformal field theories. We find a general formula for the relative entropy between two primary states with the same conformal dimension in the limit of a single small interval and find that in this case the relative entropy is proportional to the trace square distance. We check our general formulae by calculating the relative entropy between two generalized free fields and the trace square distance between the spin and disorder operators of the critical Ising model. We also give the leading term of the relative entropy in the small interval expansion when the two operators have different conformal dimensions. This turns out to be universal when the CFT has no primaires lighter than the stress tensor. The result reproduces the previously known special cases.

  13. Three-dimensional printing of stem cell-laden hydrogels submerged in a hydrophobic high-density fluid

    International Nuclear Information System (INIS)

    Duarte Campos, Daniela F; Blaeser, Andreas; Weber, Michael; Fischer, Horst; Jäkel, Jörg; Neuss, Sabine; Jahnen-Dechent, Wilhelm

    2013-01-01

    Over the last decade, bioprinting technologies have begun providing important tissue engineering strategies for regenerative medicine and organ transplantation. The major drawback of past approaches has been poor or inadequate material-printing device and substrate combinations, as well as the relatively small size of the printed construct. Here, we hypothesise that cell-laden hydrogels can be printed when submerged in perfluorotributylamine (C 12 F 27 N), a hydrophobic high-density fluid, and that these cells placed within three-dimensional constructs remain viable allowing for cell proliferation and production of extracellular matrix. Human mesenchymal stem cells and MG-63 cells were encapsulated into agarose hydrogels, and subsequently printed in high aspect ratio in three dimensional structures that were supported in high density fluorocarbon. Three-dimensional structures with various shapes and sizes were manufactured and remained stable for more than six months. Live/dead and DAPI stainings showed viable cells 24 h after the printing process, as well as after 21 days in culture. Histological and immunohistochemical analyses after 14 and 21 days revealed viable cells with marked matrix production and signs of proliferation. The compressive strength values of the printed gels consequently increased during the two weeks in culture, revealing encouraging results for future applications in regenerative medicine. (paper)

  14. The role and strategy of IMRT in radiotherapy of pelvic tumors: Dose escalation and critical organ sparing in prostate cancer

    International Nuclear Information System (INIS)

    Liu, Y.-M.; Shiau, C.-Y.; Lee, M.-L.; Huang, P.-I.; Hsieh, C.-M.; Chen, P.-H.; Lin, Y.-H.; Wang, L.-W.; Yen, S.-H.

    2007-01-01

    Purpose: To investigate the intensity-modulated radiotherapy (IMRT) strategy in dose escalation of prostate and pelvic lymph nodes. Methods and Materials: Plan dosimetric data of 10 prostate cancer patients were compared with two-dimensional (2D) or IMRT techniques for pelvis (two-dimensional whole pelvic radiation therapy [2D-WPRT] or IM-WPRT) to receive 50 Gy or 54 Gy and additional prostate boost by three-dimensional conformal radiation therapy or IMRT (3D-PBRT or IM-PBRT) techniques up to 72 Gy or 78 Gy. Dose-volume histograms (DVHs), normal tissue complication probabilities (NTCP) of critical organ, and conformity of target volume in various combinations were calculated. Results: In DVH analysis, the plans with IM-WPRT (54 Gy) and additional boost up to 78 Gy had lower rectal and bladder volume percentage at 50 Gy and 60 Gy, compared with those with 2D-WPRT (50 Gy) and additional boost up to 72 Gy or 78 Gy. Those with IM-WPRT (54 Gy) also had better small bowel sparing at 30 Gy and 50 Gy, compared with those with 2D-WPRT (50 Gy). In NTCP, those with IM-WPRT and total dose of 78 Gy achieved lower complication rates in rectum and small bowel, compared with those of 2D-WPRT with total dose of 72 Gy. In conformity, those with IM-WPRT had better conformity compared with those with 2D-WPRT with significance (p < 0.005). No significant difference in DVHs, NTCP, or conformity was found between IM-PBRT and 3D-PBRT after IM-WPRT. Conclusions: Initial pelvic IMRT is the most important strategy in dose escalation and critical organ sparing. IM-WPRT is recommended for patients requiring WPRT. There is not much benefit for critical organ sparing by IMRT after 2D-WPRT

  15. Multiscale modeling of three-dimensional genome

    Science.gov (United States)

    Zhang, Bin; Wolynes, Peter

    The genome, the blueprint of life, contains nearly all the information needed to build and maintain an entire organism. A comprehensive understanding of the genome is of paramount interest to human health and will advance progress in many areas, including life sciences, medicine, and biotechnology. The overarching goal of my research is to understand the structure-dynamics-function relationships of the human genome. In this talk, I will be presenting our efforts in moving towards that goal, with a particular emphasis on studying the three-dimensional organization, the structure of the genome with multi-scale approaches. Specifically, I will discuss the reconstruction of genome structures at both interphase and metaphase by making use of data from chromosome conformation capture experiments. Computationally modeling of chromatin fiber at atomistic level from first principles will also be presented as our effort for studying the genome structure from bottom up.

  16. Implementation of three dimensional treatment planning system for external radiotherapy

    International Nuclear Information System (INIS)

    Major, Tibor; Kurup, P.G.G.; Stumpf, Janos

    1997-01-01

    A three dimensional (3D) treatment planning system was installed at Apollo Cancer Hospital, Chennai, India in 1995. This paper gives a short description of the system including hardware components, calculation algorithm, measured data requirements and specific three dimensional features. The concept and the structure of the system are shortly described. The first impressions along with critical opinions and the experiences are gained during the data acquisition are mentioned. Some improvements in the user interface are suggested. It is emphasized that although a 3D system offers more detailed and accurate dose distributions compared to a 2D system, it also introduces a greatly increased workload for the planning staff. (author)

  17. Comparisons of dose-volume histograms for proton-beam versus 3-D conformal X-ray therapy in patients with stage I non-small cell lung cancer

    International Nuclear Information System (INIS)

    Wang, Changlu; Nakayama, Hidetsugu; Sugahara, Shinji; Sakae, Takeji; Tokuuye, Koichi

    2009-01-01

    Dose-volume histograms (DVHs) were reviewed to determine if there is an advantage of the two modalities when treating patients with non-small cell lung cancer (NSCLC). 24 stage I NSCLC patients who underwent proton-beam therapy (PBT) from June 2003 to May 2007 were included in this study. Based on the same clinical target volumes (CTVs), treatment planning was made to cover CTV within 90% isodose lines. Each patient was evaluated by two sets of DVHs, one for PBT and the other for three-dimensional conformal X-ray therapy (3D-CRT). For all patients, the 95% isodose line covered 86.4% of the CTV for PBT, and 43.2% for 3D-CRT. PBT was associated with significantly lower mean doses to the ipsilateral lung, total lung, heart, esophagus, and spinal cord than 3D-CRT. PBT offered reduced radiation doses to the lung when evaluated in terms of percentage lung volumes receiving ≥ 5 Gy (V 5 ), ≥ 10 Gy (V 10 ), and ≥ 20 Gy (V 20 ) when compared to 3D-CRT. PBT is advantageous over 3D-CRT in reducing doses to the lung, heart, esophagus, and spinal cord in treating stage I NSCLC. (orig.)

  18. Three-dimensional, three-component wall-PIV

    Science.gov (United States)

    Berthe, André; Kondermann, Daniel; Christensen, Carolyn; Goubergrits, Leonid; Garbe, Christoph; Affeld, Klaus; Kertzscher, Ulrich

    2010-06-01

    This paper describes a new time-resolved three-dimensional, three-component (3D-3C) measurement technique called wall-PIV. It was developed to assess near wall flow fields and shear rates near non-planar surfaces. The method is based on light absorption according to Beer-Lambert’s law. The fluid containing a molecular dye and seeded with buoyant particles is illuminated by a monochromatic, diffuse light. Due to the dye, the depth of view is limited to the near wall layer. The three-dimensional particle positions can be reconstructed by the intensities of the particle’s projection on an image sensor. The flow estimation is performed by a new algorithm, based on learned particle trajectories. Possible sources of measurement errors related to the wall-PIV technique are analyzed. The accuracy analysis was based on single particle experiments and a three-dimensional artificial data set simulating a rotating sphere.

  19. Problems of high temperature superconductivity in three-dimensional systems

    Energy Technology Data Exchange (ETDEWEB)

    Geilikman, B T

    1973-01-01

    A review is given of more recent papers on this subject. These papers have dealt mainly with two-dimensional systems. The present paper extends the treatment to three-dimensional systems, under the following headings: systems with collective electrons of one group and localized electrons of another group (compounds of metals with non-metals-dielectrics, organic substances, undoped semiconductors, molecular crystals); experimental investigations of superconducting compounds of metals with organic compounds, dielectrics, semiconductors, and semi-metals; and systems with two or more groups of collective electrons. Mechanics are considered and models are derived. 86 references.

  20. Conformational sampling in template-free protein loop structure modeling: an overview.

    Science.gov (United States)

    Li, Yaohang

    2013-01-01

    Accurately modeling protein loops is an important step to predict three-dimensional structures as well as to understand functions of many proteins. Because of their high flexibility, modeling the three-dimensional structures of loops is difficult and is usually treated as a "mini protein folding problem" under geometric constraints. In the past decade, there has been remarkable progress in template-free loop structure modeling due to advances of computational methods as well as stably increasing number of known structures available in PDB. This mini review provides an overview on the recent computational approaches for loop structure modeling. In particular, we focus on the approaches of sampling loop conformation space, which is a critical step to obtain high resolution models in template-free methods. We review the potential energy functions for loop modeling, loop buildup mechanisms to satisfy geometric constraints, and loop conformation sampling algorithms. The recent loop modeling results are also summarized.

  1. CONFORMATIONAL SAMPLING IN TEMPLATE-FREE PROTEIN LOOP STRUCTURE MODELING: AN OVERVIEW

    Directory of Open Access Journals (Sweden)

    Yaohang Li

    2013-02-01

    Full Text Available Accurately modeling protein loops is an important step to predict three-dimensional structures as well as to understand functions of many proteins. Because of their high flexibility, modeling the three-dimensional structures of loops is difficult and is usually treated as a “mini protein folding problem” under geometric constraints. In the past decade, there has been remarkable progress in template-free loop structure modeling due to advances of computational methods as well as stably increasing number of known structures available in PDB. This mini review provides an overview on the recent computational approaches for loop structure modeling. In particular, we focus on the approaches of sampling loop conformation space, which is a critical step to obtain high resolution models in template-free methods. We review the potential energy functions for loop modeling, loop buildup mechanisms to satisfy geometric constraints, and loop conformation sampling algorithms. The recent loop modeling results are also summarized.

  2. Three-dimensional compound comparison methods and their application in drug discovery.

    Science.gov (United States)

    Shin, Woong-Hee; Zhu, Xiaolei; Bures, Mark Gregory; Kihara, Daisuke

    2015-07-16

    Virtual screening has been widely used in the drug discovery process. Ligand-based virtual screening (LBVS) methods compare a library of compounds with a known active ligand. Two notable advantages of LBVS methods are that they do not require structural information of a target receptor and that they are faster than structure-based methods. LBVS methods can be classified based on the complexity of ligand structure information utilized: one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D). Unlike 1D and 2D methods, 3D methods can have enhanced performance since they treat the conformational flexibility of compounds. In this paper, a number of 3D methods will be reviewed. In addition, four representative 3D methods were benchmarked to understand their performance in virtual screening. Specifically, we tested overall performance in key aspects including the ability to find dissimilar active compounds, and computational speed.

  3. Conformal field theory in conformal space

    International Nuclear Information System (INIS)

    Preitschopf, C.R.; Vasiliev, M.A.

    1999-01-01

    We present a new framework for a Lagrangian description of conformal field theories in various dimensions based on a local version of d + 2-dimensional conformal space. The results include a true gauge theory of conformal gravity in d = (1, 3) and any standard matter coupled to it. An important feature is the automatic derivation of the conformal gravity constraints, which are necessary for the analysis of the matter systems

  4. Development of NTCP models for head and neck cancer patients treated with three-dimensional conformal radiotherapy for xerostomia and sticky saliva: The role of dosimetric and clinical factors

    International Nuclear Information System (INIS)

    Beetz, Ivo; Schilstra, Cornelis; Burlage, Fred R.; Koken, Phil W.; Doornaert, Patricia; Bijl, Henk P.; Chouvalova, Olga; Leemans, C. René; Bock, Geertruida H. de; Christianen, Miranda E.M.C.; Laan, Bernard F.A.M. van der; Vissink, Arjan; Steenbakkers, Roel J.H.M.; Langendijk, Johannes A.

    2012-01-01

    Purpose: The purpose of this multicentre prospective study was to investigate the significance of the radiation dose in the major and minor salivary glands, and other pre-treatment and treatment factors, with regard to the development of patient-rated xerostomia and sticky saliva among head and neck cancer (HNC) patients treated with primary (chemo-) radiotherapy ((CH)RT). Methods and materials: The study population was composed of 167 consecutive HNC patients treated with three-dimensional conformal (3D-CRT) (CH) RT. The primary endpoint was moderate to severe xerostomia (XER6m) as assessed by the EORTC QLQ-H and N35 at 6 months after completing (CH)RT. The secondary endpoint was moderate to severe sticky saliva at 6 months (STIC6 m). All organs at risk (OARs) potentially involved in salivary function were delineated on planning-CT, including the parotid, submandibular and sublingual glands and the minor glands in the soft palate, cheeks and lips. Patients with moderate to severe xerostomia or sticky saliva at baseline were excluded. The optimum number of variables for a multivariate logistic regression model was determined using a bootstrapping method. Results: The multivariate analysis showed the mean parotid dose, age and baseline xerostomia (none versus a bit) to be the most important predictors for XER6m. The risk of developing xerostomia increased with age and was higher when minor baseline xerostomia was present in comparison with patients without any xerostomia complaints at baseline. Model performance was good with an area under the curve (AUC) of 0.82. For STIC6m, the mean submandibular dose, age, the mean sublingual dose and baseline sticky saliva (none versus a bit) were most predictive for sticky saliva. The risk of developing STIC6 m increased with age and was higher when minor baseline sticky saliva was present in comparison with patients without any sticky saliva complaints at baseline. Model performance was good with an AUC of 0.84. Conclusions

  5. Analysis of Operating Performance and Three Dimensional Magnetic Field of High Voltage Induction Motors with Stator Chute

    Directory of Open Access Journals (Sweden)

    WANG Qing-shan

    2017-06-01

    Full Text Available In view of the difficulties on technology of rotor chute in high voltage induction motor,the desig method adopted stator chute structure is put forward. The mathematical model of three dimensional nonlinear transient field for solving stator chute in high voltage induction motor is set up. Through the three dimensional entity model of motor,three dimensional finite element method based on T,ψ - ψ electromagnetic potential is adopted for the analysis and calculation of stator chute in high voltage induction motor under rated condition. The distributions long axial of fundamental wave magnetic field and tooth harmonic wave magnetic field are analyzed after stator chute,and the weakening effects on main tooth harmonic magnetic field are researched. Further more,the comparison analysis of main performance parameters of chute and straight slot is carried out under rated condition. The results show that the electrical performance of stator chute is better than that of straight slot in high voltage induction motor,and the tooth harmonic has been sharply decreased

  6. Reduced, three-dimensional, nonlinear equations for high-β plasmas including toroidal effects

    International Nuclear Information System (INIS)

    Schmalz, R.

    1980-11-01

    The resistive MHD equations for toroidal plasma configurations are reduced by expanding to the second order in epsilon, the inverse aspect ratio, allowing for high β = μsub(o)p/B 2 of order epsilon. The result is a closed system of nonlinear, three-dimensional equations where the fast magnetohydrodynamic time scale is eliminated. In particular, the equation for the toroidal velocity remains decoupled. (orig.)

  7. The evolution of rectal and urinary toxicity and immune response in prostate cancer patients treated with two three-dimensional conformal radiotherapy techniques

    International Nuclear Information System (INIS)

    Vranova, Jana; Vinakurau, Stepan; Richter, Jan; Starec, Miroslav; Fiserova, Anna; Rosina, Jozef

    2011-01-01

    Our research compared whole pelvic (WP) and prostate-only (PO) 3-dimensional conformal radiotherapy (3DCRT) techniques in terms of the incidence and evolution of acute and late toxicity of the rectum and urinary bladder, and identified the PTV-parameters influencing these damages and changes in antitumor immune response. We analyzed 197 prostate cancer patients undergoing 3DCRT for gastrointestinal (GI) and genitourinary (GU) toxicities, and conducted a pilot immunological study including flow cytometry and an NK cell cytotoxicity assay. Acute and late toxicities were recorded according to the RTOG and the LENT-SOMA scales, respectively. Univariate and multivariate analyses were conducted for factors associated with toxicity. In the WP group, an increase of acute rectal toxicity was observed. A higher incidence of late GI/GU toxicity appeared in the PO group. Only 18 patients (WP-7.76% and PO-11.11%) suffered severe late GI toxicity, and 26 patients (WP-11.21% and PO-16.05%) severe late GU toxicity. In the majority of acute toxicity suffering patients, the diminution of late GI/GU toxicity to grade 1 or to no toxicity after radiotherapy was observed. The 3DCRT technique itself, patient age, T stage of TNM classification, surgical intervention, and some dose-volume parameters emerged as important factors in the probability of developing acute and late GI/GU toxicity. The proportion and differentiation of NK cells positively correlated during 3DCRT and negatively so after its completion with dose-volumes of the rectum and urinary bladder. T and NKT cells were down-regulated throughout the whole period. We found a negative correlation between leukocyte numbers and bone marrow irradiated by 44-54 Gy and a positive one for NK cell proportion and doses of 5-25 Gy. The acute GU, late GU, and GI toxicities up-regulated the T cell (CTL) numbers and NK cytotoxicity. Our study demonstrates the association of acute and late damage of the urinary bladder and rectum, with

  8. Visualizing and quantifying dose distribution in a UV reactor using three-dimensional laser-induced fluorescence.

    Science.gov (United States)

    Gandhi, Varun N; Roberts, Philip J W; Kim, Jae-Hong

    2012-12-18

    Evaluating the performance of typical water treatment UV reactors is challenging due to the complexity in assessing spatial and temporal variation of UV fluence, resulting from highly unsteady, turbulent nature of flow and variation in UV intensity. In this study, three-dimensional laser-induced fluorescence (3DLIF) was applied to visualize and quantitatively analyze a lab-scale UV reactor consisting of one lamp sleeve placed perpendicular to flow. Mapping the spatial and temporal fluence delivery and MS2 inactivation revealed the highest local fluence in the wake zone due to longer residence time and higher UV exposure, while the lowest local fluence occurred in a region near the walls due to short-circuiting flow and lower UV fluence rate. Comparing the tracer based decomposition between hydrodynamics and IT revealed similar coherent structures showing the dependency of fluence delivery on the reactor flow. The location of tracer injection, varying the height and upstream distance from the lamp center, was found to significantly affect the UV fluence received by the tracer. A Lagrangian-based analysis was also employed to predict the fluence along specific paths of travel, which agreed with the experiments. The 3DLIF technique developed in this study provides new insight on dose delivery that fluctuates both spatially and temporally and is expected to aid design and optimization of UV reactors as well as validate computational fluid dynamics models that are widely used to simulate UV reactor performances.

  9. Three-dimensional, flexible graphene bioelectronics.

    Science.gov (United States)

    Chun, SungGyu; Choi, Jonghyun; Ashraf, Ali; Nam, SungWoo

    2014-01-01

    We report 3-dimensional (3D) graphene-based biosensors fabricated via 3D transfer of monolithic graphene-graphite structures. This mechanically flexible all-carbon structure is a prospective candidate for intimate 3D interfacing with biological systems. Monolithic graphene-graphite structures were synthesized using low pressure chemical vapor deposition (LPCVD) process relying on the heterostructured metal catalyst layers. Nonplanar substrates and wet-transfer method were used with a thin Au film as a transfer layer to achieve the 3D graphene structure. Instead of the typical wet-etching method, vapor-phase etching was performed to minimize the delamination of the graphene while removing the transfer layer. We believe that the monolithic graphene-graphite synthesis combined with the conformal 3D transfer will pave the way for the 3D conformal sensing capability as well as the intracellular recording of living cells in the future.

  10. High-resolution two-dimensional and three-dimensional modeling of wire grid polarizers and micropolarizer arrays

    Science.gov (United States)

    Vorobiev, Dmitry; Ninkov, Zoran

    2017-11-01

    Recent advances in photolithography allowed the fabrication of high-quality wire grid polarizers for the visible and near-infrared regimes. In turn, micropolarizer arrays (MPAs) based on wire grid polarizers have been developed and used to construct compact, versatile imaging polarimeters. However, the contrast and throughput of these polarimeters are significantly worse than one might expect based on the performance of large area wire grid polarizers or MPAs, alone. We investigate the parameters that affect the performance of wire grid polarizers and MPAs, using high-resolution two-dimensional and three-dimensional (3-D) finite-difference time-domain simulations. We pay special attention to numerical errors and other challenges that arise in models of these and other subwavelength optical devices. Our tests show that simulations of these structures in the visible and near-IR begin to converge numerically when the mesh size is smaller than ˜4 nm. The performance of wire grid polarizers is very sensitive to the shape, spacing, and conductivity of the metal wires. Using 3-D simulations of micropolarizer "superpixels," we directly study the cross talk due to diffraction at the edges of each micropolarizer, which decreases the contrast of MPAs to ˜200∶1.

  11. Diagnosing Chaos Using Four-Point Functions in Two-Dimensional Conformal Field Theory.

    Science.gov (United States)

    Roberts, Daniel A; Stanford, Douglas

    2015-09-25

    We study chaotic dynamics in two-dimensional conformal field theory through out-of-time-order thermal correlators of the form ⟨W(t)VW(t)V⟩. We reproduce holographic calculations similar to those of Shenker and Stanford, by studying the large c Virasoro identity conformal block. The contribution of this block to the above correlation function begins to decrease exponentially after a delay of ~t_{*}-(β/2π)logβ^{2}E_{w}E_{v}, where t_{*} is the fast scrambling time (β/2π)logc and E_{w},E_{v} are the energy scales of the W,V operators.

  12. Acute small bowel toxicity and preoperative chemoradiotherapy for rectal cancer: Investigating dose-volume relationships and role for inverse planning

    International Nuclear Information System (INIS)

    Tho, Lye Mun; Glegg, Martin; Paterson, Jennifer; Yap, Christina; MacLeod, Alice; McCabe, Marie; McDonald, Alexander C.

    2006-01-01

    Purpose: The relationship between volume of irradiated small bowel (VSB) and acute toxicity in rectal cancer radiotherapy is poorly quantified, particularly in patients receiving concurrent preoperative chemoradiotherapy. Using treatment planning data, we studied a series of such patients. Methods and Materials: Details of 41 patients with locally advanced rectal cancer were reviewed. All received 45 Gy in 25 fractions over 5 weeks, 3-4 fields three-dimensional conformal radiotherapy with daily 5-fluorouracil and folinic acid during Weeks 1 and 5. Toxicity was assessed prospectively in a weekly clinic. Using computed tomography planning software, the VSB was determined at 5 Gy dose intervals (V 5 , V 1 , etc.). Eight patients with maximal VSB had dosimetry and radiobiological modeling outcomes compared between inverse and conformal three-dimensional planning. Results: VSB correlated strongly with diarrheal severity at every dose level (p 5 and V 15 . Conclusions: A strong dose-volume relationship exists between VSB and acute diarrhea at all dose levels during preoperative chemoradiotherapy. Our constructed model may be useful in predicting toxicity, and this has been derived without the confounding influence of surgical excision on bowel function. Inverse planning can reduce calculated dose to small bowel and late NTCP, and its clinical role warrants further investigation

  13. Feasibility of four-dimensional conformal planning for robotic radiosurgery

    International Nuclear Information System (INIS)

    Schlaefer, A.; Fisseler, J.; Dieterich, S.; Shiomi, H.; Cleary, K.; Schweikard, A.

    2005-01-01

    Organ motion can have a severe impact on the dose delivered by radiation therapy, and different procedures have been developed to address its effects. Conventional techniques include breath hold methods and gating. A different approach is the compensation for target motion by moving the treatment beams synchronously. Practical results have been reported for robot based radiosurgery, where a linear accelerator mounted on a robotic arm delivers the dose. However, not all organs move in the same way, which results in a relative motion of the beams with respect to the body and the tissues in the proximity of the tumor. This relative motion can severely effect the dose delivered to critical structures. We propose a method to incorporate motion in the treatment planning for robotic radiosurgery to avoid potential overdosing of organs surrounding the target. The method takes into account the motion of all considered volumes, which is discretized for dose calculations. Similarly, the beam motion is taken into account and the aggregated dose coefficient over all discrete steps is used for planning. We simulated the treatment of a moving target with three different planning methods. First, we computed beam weights based on a 3D planning situation and simulated treatment with organ motion and the beams moving synchronously to the target. Second, beam weights were computed by the 4D planning method incorporating the organ and beam motion and treatment was simulated for beams moving synchronously to the target. Third, the beam weights were determined by the 4D planning method with the beams fixed during planning and simulation. For comparison we also give results for the 3D treatment plan if there was no organ motion and when the plan is delivered by fixed beams in the presence of organ motion. The results indicate that the new 4D method is preferable and can further improve the overall conformality of motion compensated robotic radiosurgery

  14. Three Dimensional Dirac Semimetals

    Science.gov (United States)

    Zaheer, Saad

    2014-03-01

    Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments. Work carried out in collaboration with: Julia A. Steinberg, Steve M. Young, J.C.Y. Teo, C.L. Kane, E.J. Mele and Andrew M. Rappe.

  15. Large Bone Vertical Augmentation Using a Three-Dimensional Printed TCP/HA Bone Graft: A Pilot Study in Dog Mandible

    OpenAIRE

    Carrel, Jean-Pierre; Wiskott, Anselm; Scherrer, Susanne; Durual, Stéphane

    2016-01-01

    Osteoflux is a three-dimensional printed calcium phosphate porous structure for oral bone augmentation. It is a mechanically stable scaffold with a well-defined interconnectivity and can be readily shaped to conform to the bone bed's morphology

  16. Three-dimensional effects in fracture mechanics

    International Nuclear Information System (INIS)

    Benitez, F.G.

    1991-01-01

    An overall view of the pioneering theories and works, which enlighten the three-dimensional nature of fracture mechanics during the last years is given. the main aim is not an exhaustive reviewing but the displaying of the last developments on this scientific field in a natural way. This work attempts to envisage the limits of disregarding the three-dimensional behaviour in theories, analyses and experiments. Moreover, it tries to draw attention on the scant fervour, although increasing, this three-dimensional nature of fracture has among the scientific community. Finally, a constructive discussion is presented on the use of two-dimensional solutions in the analysis of geometries which bear a three-dimensional configuration. the static two-dimensional solutions and its applications fields are reviewed. also, the static three-dimensional solutions, wherein a comparative analysis with elastoplastic and elastostatic solutions are presented. to end up, the dynamic three-dimensional solutions are compared to the asymptotic two-dimensional ones under the practical applications point of view. (author)

  17. Introduction to the conformational investigation of peptides and proteins by using two-dimensional proton NMR experiments

    International Nuclear Information System (INIS)

    Neumann, J.M.; Macquaire, F.

    1991-01-01

    This report presents the elementary bases for an initiation to the conformational study of peptides and proteins by using two-dimensional proton NMR experiments. First, some general features of protein structures are summarized. A second chapter is devoted to the basic NMR experiments and to the spectral parameters which provide a structural information. This description is illustrated by NMR spectra of peptides. The third chapter concerns the most standard two-dimensional proton NMR experiments and their use for a conformational study of peptides and proteins. Lastly, an example of NMR structural investigation of a peptide is reported [fr

  18. Three-dimensional dose accumulation in pseudo-split-field IMRT and brachytherapy for locally advanced cervical cancer.

    Science.gov (United States)

    Sun, Baozhou; Yang, Deshan; Esthappan, Jackie; Garcia-Ramirez, Jose; Price, Samantha; Mutic, Sasa; Schwarz, Julie K; Grigsby, Perry W; Tanderup, Kari

    2015-01-01

    Dose accumulation of split-field external beam radiotherapy (EBRT) and brachytherapy (BT) is challenging because of significant EBRT and BT dose gradients in the central pelvic region. We developed a method to determine biologically effective dose parameters for combined split-field intensity-modulated radiation therapy (IMRT) and image-guided BT in locally advanced cervical cancer. Thirty-three patients treated with split-field-IMRT to 45.0-51.2 Gy in 1.6-1.8 Gy per fraction to the elective pelvic lymph nodes and to 20 Gy to the central pelvis region were included in this study. Patients received six weekly fractions of high-dose rate BT to 6.5-7.3 Gy per fraction. A dose tracker software was developed to compute the equivalent dose in 2-Gy fractions (EQD2) to gross tumor volume (GTV), organs-at-risk and point A. Total dose-volume histogram parameters were computed on the 3D combined EQD2 dose based on rigid image registration. The dose accumulation uncertainty introduced by organ deformations between IMRT and BT was evaluated. According to International Commission on Radiation Unit and Measurement and GEC European Society for Therapeutic Radiology and Oncology recommendations, D98, D90, D50, and D2cm3 EQD2 dose-volume histogram parameters were computed. GTV D98 was 84.0 ± 26.5 Gy and D2cc was 99.6 ± 13.9 Gy, 67.4 ± 12.2 Gy, 75.0 ± 10.1 Gy, for bladder, rectum, and sigmoid, respectively. The uncertainties induced by organ deformation were estimated to be -1 ± 4 Gy, -3 ± 5 Gy, 2 ± 3 Gy, and -3 ± 5 Gy for bladder, rectum, sigmoid, and GTV, respectively. It is feasible to perform 3D EQD2 dose accumulation to assess high and intermediate dose regions for combined split-field IMRT and BT. Copyright © 2015 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

  19. The three-dimensional genome organization of Drosophila melanogaster through data integration.

    Science.gov (United States)

    Li, Qingjiao; Tjong, Harianto; Li, Xiao; Gong, Ke; Zhou, Xianghong Jasmine; Chiolo, Irene; Alber, Frank

    2017-07-31

    Genome structures are dynamic and non-randomly organized in the nucleus of higher eukaryotes. To maximize the accuracy and coverage of three-dimensional genome structural models, it is important to integrate all available sources of experimental information about a genome's organization. It remains a major challenge to integrate such data from various complementary experimental methods. Here, we present an approach for data integration to determine a population of complete three-dimensional genome structures that are statistically consistent with data from both genome-wide chromosome conformation capture (Hi-C) and lamina-DamID experiments. Our structures resolve the genome at the resolution of topological domains, and reproduce simultaneously both sets of experimental data. Importantly, this data deconvolution framework allows for structural heterogeneity between cells, and hence accounts for the expected plasticity of genome structures. As a case study we choose Drosophila melanogaster embryonic cells, for which both data types are available. Our three-dimensional genome structures have strong predictive power for structural features not directly visible in the initial data sets, and reproduce experimental hallmarks of the D. melanogaster genome organization from independent and our own imaging experiments. Also they reveal a number of new insights about genome organization and its functional relevance, including the preferred locations of heterochromatic satellites of different chromosomes, and observations about homologous pairing that cannot be directly observed in the original Hi-C or lamina-DamID data. Our approach allows systematic integration of Hi-C and lamina-DamID data for complete three-dimensional genome structure calculation, while also explicitly considering genome structural variability.

  20. Three-dimensional iron sulfide-carbon interlocked graphene composites for high-performance sodium-ion storage

    DEFF Research Database (Denmark)

    Huang, Wei; Sun, Hongyu; Shangguan, Huihui

    2018-01-01

    Three-dimensional (3D) carbon-wrapped iron sulfide interlocked graphene (Fe7S8@C-G) composites for high-performance sodium-ion storage are designed and produced through electrostatic interactions and subsequent sulfurization. The iron-based metal–organic frameworks (MOFs, MIL-88-Fe) interact with...

  1. Three-Dimensional Compound Comparison Methods and Their Application in Drug Discovery

    Directory of Open Access Journals (Sweden)

    Woong-Hee Shin

    2015-07-01

    Full Text Available Virtual screening has been widely used in the drug discovery process. Ligand-based virtual screening (LBVS methods compare a library of compounds with a known active ligand. Two notable advantages of LBVS methods are that they do not require structural information of a target receptor and that they are faster than structure-based methods. LBVS methods can be classified based on the complexity of ligand structure information utilized: one-dimensional (1D, two-dimensional (2D, and three-dimensional (3D. Unlike 1D and 2D methods, 3D methods can have enhanced performance since they treat the conformational flexibility of compounds. In this paper, a number of 3D methods will be reviewed. In addition, four representative 3D methods were benchmarked to understand their performance in virtual screening. Specifically, we tested overall performance in key aspects including the ability to find dissimilar active compounds, and computational speed.

  2. Relationships Between Rectal Wall Dose-Volume Constraints and Radiobiologic Indices of Toxicity for Patients With Prostate Cancer

    International Nuclear Information System (INIS)

    Marzi, Simona; Arcangeli, Giorgio; Saracino, Bianca; Petrongari, Maria G.; Bruzzaniti, Vicente; Iaccarino, Giuseppe; Landoni, Valeria; Soriani, Antonella; Benassi, Marcello

    2007-01-01

    Purpose: The purpose of this article was to investigate how exceeding specified rectal wall dose-volume constraints impacts on the risk of late rectal bleeding by using radiobiologic calculations. Methods and Materials: Dose-volume histograms (DVH) of the rectal wall of 250 patients with prostate cancer were analyzed. All patients were treated by three-dimensional conformal radiation therapy, receiving mean target doses of 80 Gy. To study the main features of the patient population, the average and the standard deviation of the distribution of DVHs were generated. The mean dose , generalized equivalent uniform dose formulation (gEUD), modified equivalent uniform dose formulation (mEUD) 0 , and normal tissue complication probability (NTCP) distributions were also produced. The DVHs set was then binned into eight classes on the basis of the exceeding or the fulfilling of three dose-volume constraints: V 40 = 60%, V 50 = 50%, and V 70 = 25%. Comparisons were made between them by , gEUD, mEUD 0 , and NTCP. Results: The radiobiologic calculations suggest that late rectal toxicity is mostly influenced by V 70 . The gEUD and mEUD 0 are risk factors of toxicity always concordant with NTCP, inside each DVH class. The mean dose, although a reliable index, may be misleading in critical situations. Conclusions: Both in three-dimensional conformal radiation therapy and particularly in intensity-modulated radiation therapy, it should be known what the relative importance of each specified dose-volume constraint is for each organ at risk. This requires a greater awareness of radiobiologic properties of tissues and radiobiologic indices may help to gradually become aware of this issue

  3. Dosimetric advancement of high-dose-rate after-loading 192Ir source

    International Nuclear Information System (INIS)

    Zhang Shuxu; Li Wenhua; Xu Hairong

    2004-01-01

    High-dose-rate (HDR) 192 Ir source is a nuclide commonly used in the brachytherapy system. The basic dosimetry data of the near source area is usually measured by pin ion chambers or TLD techniques, but these methods have a lower spatial resolution than Electron spin resonance (ESR) dosimetry which has a spatial resolution of 156 μm, and the Monte Carlo photon transport simulations are taken as the golden standard of those measures. The precision in two-dimensional dose distribution measured by GafChromic film is reported to be 1.0%. In vivo dosimetry using TLD during HDR intracavitary after-loading brachytherapy is a good predictor of late rectal complications. The accuracy of magnetic resonance imaging (MRI) Fricke-gel dosimetry for three-dimensional dose distribution is about 2.5% with a spatial resolution of 1.56 mm. The optical computed tomography polymer gel dosimetry has a unique advance than MRI gel dosimetry

  4. Investigating Hydrocarbon Seep Environments with High-Resolution, Three-Dimensional Geographic Visualizations.

    Science.gov (United States)

    Doolittle, D. F.; Gharib, J. J.; Mitchell, G. A.

    2015-12-01

    Detailed photographic imagery and bathymetric maps of the seafloor acquired by deep submergence vehicles such as Autonomous Underwater Vehicles (AUV) and Remotely Operated Vehicles (ROV) are expanding how scientists and the public view and ultimately understand the seafloor and the processes that modify it. Several recently acquired optical and acoustic datasets, collected during ECOGIG (Ecosystem Impacts of Oil and Gas Inputs to the Gulf) and other Gulf of Mexico expeditions using the National Institute for Undersea Science Technology (NIUST) Eagle Ray, and Mola Mola AUVs, have been fused with lower resolution data to create unique three-dimensional geovisualizations. Included in these data are multi-scale and multi-resolution visualizations over hydrocarbon seeps and seep related features. Resolution of the data range from 10s of mm to 10s of m. When multi-resolution data is integrated into a single three-dimensional visual environment, new insights into seafloor and seep processes can be obtained from the intuitive nature of three-dimensional data exploration. We provide examples and demonstrate how integration of multibeam bathymetry, seafloor backscatter data, sub-bottom profiler data, textured photomosaics, and hull-mounted multibeam acoustic midwater imagery are made into a series a three-dimensional geovisualizations of actively seeping sites and associated chemosynthetic communities. From these combined and merged datasets, insights on seep community structure, morphology, ecology, fluid migration dynamics, and process geomorphology can be investigated from new spatial perspectives. Such datasets also promote valuable inter-comparisons of sensor resolution and performance.

  5. Potential clinical efficacy of intensity-modulated conformal therapy

    International Nuclear Information System (INIS)

    Meeks, Sanford L.; Buatti, John M.; Bova, Francis J.; Friedman, William A.; Mendenhall, William M.; Zlotecki, Robert A.

    1998-01-01

    Purpose: The purpose of this study was to examine the potential benefit of using intensity-modulated conformal therapy for a variety of lesions currently treated with stereotactic radiosurgery or conventional radiotherapy. Methods and Materials: Intensity-modulated conformal treatment plans were generated for small intracranial lesions, as well as head and neck, lung, breast, and prostate cases, using the Peacock Plan[reg] treatment-planning system (Nomos Corporation). For small intracranial lesions, intensity-modulated conformal treatment plans were compared with stereotactic radiosurgery treatment plans generated for patient treatment at the University of Florida Shands Cancer Center. For other sites (head and neck, lung, breast, and prostate), plans generated using the Peacock Plan[reg] were compared with conventional treatment plans, as well as beam's-eye-view conformal treatment plans. Plan comparisons were accomplished through conventional qualitative review of two-dimensional (2D) dose distributions in conjunction with quantitative techniques, such as dose-volume histograms, dosimetric statistics, normal tissue complication probabilities, tumor control probabilities, and objective numerical scoring. Results: For small intracranial lesions, there is little difference between intensity-modulated conformal treatment planning and radiosurgery treatment planning in the conformation of high isodose lines with the target volume. However, stereotactic treatment planning provides a steeper dose gradient outside the target volume and, hence, a lower normal tissue toxicity index. For extracranial sites, objective numerical scores for beam's-eye-view and intensity-modulated conformal planning techniques are superior to scores for conventional treatment plans. The beam's-eye-view planning technique prevents geographic target misses and better excludes healthy tissues from the treatment portal. Compared with scores for the beam's-eye-view planning technique, scores for

  6. Hepatitis B Virus Reactivation After Three-Dimensional Conformal Radiotherapy in Patients With Hepatitis B Virus-Related Hepatocellular Carcinoma

    International Nuclear Information System (INIS)

    Kim, Ji Hoon; Park, Joong-Won; Kim, Tae Hyun; Koh, Dong Wook; Lee, Woo Jin; Kim, Chang-Min

    2007-01-01

    Purpose: To investigate whether three-dimensional conformal radiotherapy (3D-CRT) influences hepatitis B virus (HBV) reactivation and chronic hepatitis B (CHB) exacerbation in patients with HBV-related hepatocellular carcinoma (HCC). Methods and Materials: Of the 48 HCC patients with HBV who underwent 3D-CRT to the liver, 16 underwent lamivudine therapy before and during 3D-CRT (Group 1) and 32 did not receive antiviral therapy before 3D-CRT (Group 2). To analyze spontaneous HBV reactivation, we included a control group of 43 HCC patients who did not receive any specific treatment for HCC or CHB. Results: The cumulative rate of radiation-induced liver disease for Groups 1 and 2 was 12.5% (2 of 16) and 21.8% (7 of 32), respectively (p > 0.05). The cumulative rate of HBV reactivation was significantly greater in Group 2 (21.8%, 7 of 32) than in Group 1 (0%, 0/16) or the control group (2.3%, 1 of 43; p 0.05 each). The CHB exacerbations in the 4 Group 2 patients had radiation-induced liver disease features but were differentiated by serum HBV DNA changes. Two of these patients required antiviral therapy and effectively recovered with lamivudine therapy. Conclusions: In patients with HBV-related HCC undergoing 3D-CRT, HBV reactivation and consequent CHB exacerbation should be considered in the differential diagnosis of radiation-induced liver disease, and antiviral therapy might be considered for the prevention of liver function deterioration after RT

  7. Outcome of three-dimensional conformal radiation therapy and intensity-modulated radiation therapy for inoperable locally advanced pancreatic cancer

    International Nuclear Information System (INIS)

    Lu Ningning; Jin Jing; Li Yexiong; Yu Zihao; Liu Xinfan; Wang Weihu; Wang Shulian; Song Yongwen; Liu Yuping

    2009-01-01

    Objective: To evaluate the outcome of radiotherapy for locally advanced pancreatic cancer. Methods: From January 2000 to December 2007, 41 patients with inoperable locally advanced (stage III) pancreatic cancer were treated with three-dimensional conformal radiation therapy(3DCRT) or intensity-modulated radiation therapy (IMRT). Among these patients, 30 received concurrent radio-chemo-therapy. Results: The median survival time(MST) and 1-year overall survival were 9.2 months and 23%. Patients with pretreatment KPS ≥ 80, no regional lymph nodes metastasis, and CR/PR after radiotherapy had better prognosis. The corresponding MSTs were 11.1 months vs 5.8 months (χ 2 =7.50, P=0.006), 10.8 months vs 6.5 months(χ 2 =5.67, P=0.017), and 19.5 months vs 9.1 months (χ 2 =7.28, P=0.007), respectively. Concurrent radio-chemotherapy tended to improve the overall survival(χ 2 =3.25, P=0.072). After radiotherapy, 18 patients had clinical benefit response, mainly being abdominal pain relief. Neither grade 4 hematologic nor grade 3 non-hematologic toxicities were observed. Conclusions: For patients with locally advanced pancreatic cancer, both 3DCRT and IMRT are effective in alleviation of disease-related symptoms. Patients with better performance status before treatment, no regional lymph nodes metastasis, and better response to radiotherapy may have better prognosis. Concurrent radio-chemotherapy trend to improve overall survival when compared with radiotherapy alone. (authors)

  8. Three-dimensional interconnected porous graphitic carbon derived from rice straw for high performance supercapacitors

    Science.gov (United States)

    Jin, Hong; Hu, Jingpeng; Wu, Shichao; Wang, Xiaolan; Zhang, Hui; Xu, Hui; Lian, Kun

    2018-04-01

    Three-dimensional interconnected porous graphitic carbon materials are synthesized via a combination of graphitization and activation process with rice straw as the carbon source. The physicochemical properties of the three-dimensional interconnected porous graphitic carbon materials are characterized by Nitrogen adsorption/desorption, Fourier-transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, Scanning electron microscopy and Transmission electron microscopy. The results demonstrate that the as-prepared carbon is a high surface area carbon material (a specific surface area of 3333 m2 g-1 with abundant mesoporous and microporous structures). And it exhibits superb performance in symmetric double layer capacitors with a high specific capacitance of 400 F g-1 at a current density of 0.1 A g-1, good rate performance with 312 F g-1 under a current density of 5 A g-1 and favorable cycle stability with 6.4% loss after 10000 cycles at a current density of 5 A g-1 in the aqueous electrolyte of 6M KOH. Thus, rice straw is a promising carbon source for fabricating inexpensive, sustainable and high performance supercapacitors' electrode materials.

  9. Three-dimensional biomedical imaging

    International Nuclear Information System (INIS)

    Robb, R.A.

    1985-01-01

    Scientists in biomedical imaging provide researchers, physicians, and academicians with an understanding of the fundamental theories and practical applications of three-dimensional biomedical imaging methodologies. Succinct descriptions of each imaging modality are supported by numerous diagrams and illustrations which clarify important concepts and demonstrate system performance in a variety of applications. Comparison of the different functional attributes, relative advantages and limitations, complementary capabilities, and future directions of three-dimensional biomedical imaging modalities are given. Volume 1: Introductions to Three-Dimensional Biomedical Imaging Photoelectronic-Digital Imaging for Diagnostic Radiology. X-Ray Computed Tomography - Basic Principles. X-Ray Computed Tomography - Implementation and Applications. X-Ray Computed Tomography: Advanced Systems and Applications in Biomedical Research and Diagnosis. Volume II: Single Photon Emission Computed Tomography. Position Emission Tomography (PET). Computerized Ultrasound Tomography. Fundamentals of NMR Imaging. Display of Multi-Dimensional Biomedical Image Information. Summary and Prognostications

  10. Three-dimensional distribution of cortical synapses: a replicated point pattern-based analysis

    Science.gov (United States)

    Anton-Sanchez, Laura; Bielza, Concha; Merchán-Pérez, Angel; Rodríguez, José-Rodrigo; DeFelipe, Javier; Larrañaga, Pedro

    2014-01-01

    The biggest problem when analyzing the brain is that its synaptic connections are extremely complex. Generally, the billions of neurons making up the brain exchange information through two types of highly specialized structures: chemical synapses (the vast majority) and so-called gap junctions (a substrate of one class of electrical synapse). Here we are interested in exploring the three-dimensional spatial distribution of chemical synapses in the cerebral cortex. Recent research has showed that the three-dimensional spatial distribution of synapses in layer III of the neocortex can be modeled by a random sequential adsorption (RSA) point process, i.e., synapses are distributed in space almost randomly, with the only constraint that they cannot overlap. In this study we hypothesize that RSA processes can also explain the distribution of synapses in all cortical layers. We also investigate whether there are differences in both the synaptic density and spatial distribution of synapses between layers. Using combined focused ion beam milling and scanning electron microscopy (FIB/SEM), we obtained three-dimensional samples from the six layers of the rat somatosensory cortex and identified and reconstructed the synaptic junctions. A total volume of tissue of approximately 4500μm3 and around 4000 synapses from three different animals were analyzed. Different samples, layers and/or animals were aggregated and compared using RSA replicated spatial point processes. The results showed no significant differences in the synaptic distribution across the different rats used in the study. We found that RSA processes described the spatial distribution of synapses in all samples of each layer. We also found that the synaptic distribution in layers II to VI conforms to a common underlying RSA process with different densities per layer. Interestingly, the results showed that synapses in layer I had a slightly different spatial distribution from the other layers. PMID:25206325

  11. Role of prostate dose escalation in patients with greater than 15% risk of pelvic lymph node involvement

    International Nuclear Information System (INIS)

    Jacob, Rojymon; Hanlon, Alexandra L.; Horwitz, Eric M.; Movsas, Benjamin; Uzzo, Robert G.; Pollack, Alan

    2005-01-01

    Purpose: To determine whether the radiation dose is a determinant of clinical outcome in patients with a lymph node risk of >15% treated using whole pelvic (WP), partial pelvic (PP), or prostate only (PO) fields. Methods and materials: A total of 420 patients with prostate cancer treated with three-dimensional conformal radiotherapy with or without short-term androgen deprivation (STAD) between June 1989 and July 2000 were included in this study. Patients had an initial pretreatment prostate-specific antigen level of 15% in the patient population studied. These data suggest that the primary tumor takes precedence over lymph node coverage or the use of STAD. Doses >70 Gy are of paramount importance in such intermediate- and high-risk patients

  12. Three-dimensional neuroimaging

    International Nuclear Information System (INIS)

    Toga, A.W.

    1990-01-01

    This book reports on new neuroimaging technologies that are revolutionizing the study of the brain be enabling investigators to visualize its structure and entire pattern of functional activity in three dimensions. The book provides a theoretical and practical explanation of the new science of creating three-dimensional computer images of the brain. The coverage includes a review of the technology and methodology of neuroimaging, the instrumentation and procedures, issues of quantification, analytic protocols, and descriptions of neuroimaging systems. Examples are given to illustrate the use of three-dimensional enuroimaging to quantitate spatial measurements, perform analysis of autoradiographic and histological studies, and study the relationship between brain structure and function

  13. Three-Dimensional Messages for Interstellar Communication

    Science.gov (United States)

    Vakoch, Douglas A.

    One of the challenges facing independently evolved civilizations separated by interstellar distances is to communicate information unique to one civilization. One commonly proposed solution is to begin with two-dimensional pictorial representations of mathematical concepts and physical objects, in the hope that this will provide a foundation for overcoming linguistic barriers. However, significant aspects of such representations are highly conventional, and may not be readily intelligible to a civilization with different conventions. The process of teaching conventions of representation may be facilitated by the use of three-dimensional representations redundantly encoded in multiple formats (e.g., as both vectors and as rasters). After having illustrated specific conventions for representing mathematical objects in a three-dimensional space, this method can be used to describe a physical environment shared by transmitter and receiver: a three-dimensional space defined by the transmitter--receiver axis, and containing stars within that space. This method can be extended to show three-dimensional representations varying over time. Having clarified conventions for representing objects potentially familiar to both sender and receiver, novel objects can subsequently be depicted. This is illustrated through sequences showing interactions between human beings, which provide information about human behavior and personality. Extensions of this method may allow the communication of such culture-specific features as aesthetic judgments and religious beliefs. Limitations of this approach will be noted, with specific reference to ETI who are not primarily visual.

  14. Doses to Carotid Arteries After Modern Radiation Therapy for Hodgkin Lymphoma

    DEFF Research Database (Denmark)

    Maraldo, M.V.; Brodin, Nils Patrik; Aznar, Marianne Camille

    2013-01-01

    Hodgkin lymphoma (HL) survivors are at an increased risk of stroke because of carotid artery irradiation. However, for early-stage HL involved node radiation therapy (INRT) reduces the volume of normal tissue exposed to high doses. Here, we evaluate 3-dimensional conformal radiation therapy (3D......-CRT), volumetric-modulated arc therapy (VMAT), and proton therapy (PT) delivered as INRT along with the extensive mantle field (MF) by comparing doses to the carotid arteries and corresponding risk estimates....

  15. The treatment of nonpalpable PSA-detected adenocarcinoma of the prostate with 3-dimensional conformal radiation therapy

    International Nuclear Information System (INIS)

    Horwitz, Eric M.; Hanlon, Alexandra L.; Pinover, Wayne H.; Hanks, Gerald E.

    1998-01-01

    Purpose: We reviewed our institution's experience treating patients with nonpalpable PSA-detected prostate cancer with three-dimensional conformal radiation therapy (3DCRT) to determine prognostic factors that predict for biochemical-free survival (bNED) control and present the bNED control rates. Methods and Materials: Between May 1, 1990 and November 30, 1994, 160 patients with nonpalpable PSA-detected prostate cancer received 3DCRT at Fox Chase Cancer Center (median total dose 73 Gy; range: 67-78 Gy). bNED failure was defined as three consecutive increases in posttreatment PSA after achieving a nadir. bNED failure was recorded as the time midway between the nadir and the first consecutive rising PSA. Five-year actuarial rates of bNED control were calculated for pretreatment PSA (0-9.9 vs. 10-19.9 vs. ≥ 20 ng/ml), Gleason score (2-6 vs. 7-10), treatment field size (prostate vs. small pelvis), age ( 73 Gy) using Kaplan-Meier methods and compared using the Log rank test. The Cox model was used to multivariately establish independent predictors based on significant univariate factors. Median follow-up was 39 months (range: 2-84 months). Results: The 5-year actuarial rate of bNED control was 86% for the entire group of patients. The Cox Proportional Hazards model demonstrated that pretreatment PSA was an independent predictor of bNED control. Treatment field size was marginally predictive. There was no difference in bNED control when patients were stratified by the number of lobes positive for disease. Statistically different rates of bNED control were seen when the patients with nonpalpable disease were univariately compared to T2b and T2c patients. Three patients experienced Grade 3-4 genitourinary (GU) toxicity and 3 patients experienced Grade 3-4 gastrointestinal (GI) toxicity. Conclusions: Patients with nonpalpable PSA-detected prostate cancer can be effectively treated with 3DCRT with minimal morbidity and high rates of bNED control at 5 years. Pretreatment

  16. Three-dimensional measurements of the lower extremity in children and adolescents using a low-dose biplanar X-ray device

    International Nuclear Information System (INIS)

    Gheno, Ramon; Nectoux, Eric; Herbaux, Bernard; Baldisserotto, Matteo; Glock, Luiz; Cotten, Anne; Boutry, Nathalie

    2012-01-01

    To evaluate three-dimensional (3D) measurements of the lower extremity using a biplanar low-dose X-ray device in children and adolescents. Firstly, 3D measurements of eight dried bones were analysed by a biplanar low-dose X-ray device (LDX) using stereoscopic software and compared with 3D computed tomography (CT). Secondly, 47 lower limbs of children and adolescents were studied using LDX two-dimensional (2D) and 3D measurements. Both parts were evaluated for femoral and tibial lengths and mechanical angles, frontal and lateral knee angulations, and the femoral neck-shaft angle. The 3D specimen comparison between LDX and CT measurements showed no significant differences: femoral length (P = 0.069), tibial length (P = 0.059), femoral mechanical angle (P = 0.475), tibial mechanical angle (P = 0.067), frontal knee angulation (P = 0.198), lateral knee angulation (P = 0.646) and femoral neck-shaft angle (P = 0.068). The comparison between LDX 2D and 3D measurements showed significant differences in tibial length (P = 0.003), femoral mechanical angle (P < 0.001) and femoral neck-shaft angle (P = 0.001); other parameters were unremarkable. The 3D LDX system presented reliable measurements compared with 3D CT. Differences between LDX 2D and 3D measurements were noted in the femoral mechanical angle, femoral neck-shaft angle and tibial length. Moderate to good interobserver agreement for the 3D LDX measurements were found. (orig.)

  17. Constituent Components of Out-of-Field Scatter Dose for 18-MV Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy: A Comparison With 6-MV and Implications for Carcinogenesis

    International Nuclear Information System (INIS)

    Ruben, Jeremy D.; Smith, Ryan; Lancaster, Craig M.; Haynes, Matthew; Jones, Phillip; Panettieri, Vanessa

    2014-01-01

    Purpose: To characterize and compare the components of out-of-field dose for 18-MV intensity modulated radiation therapy (IMRT) versus 3-dimensional conformal radiation therapy (3D-CRT) and their 6-MV counterparts and consider implications for second cancer induction. Methods and Materials: Comparable plans for each technique/energy were delivered to a water phantom with a sloping wall; under full scatter conditions; with field edge abutting but outside the bath to prevent internal/phantom scatter; and with shielding below the linear accelerator head to attenuate head leakage. Neutron measurements were obtained from published studies. Results: Eighteen-megavolt IMRT produces 1.7 times more out-of-field scatter than 18-MV 3D-CRT. In absolute terms, however, differences are just approximately 0.1% of central axis dose. Eighteen-megavolt IMRT reduces internal/patient scatter by 13%, but collimator scatter (C) is 2.6 times greater than 18-MV 3D-CRT. Head leakage (L) is minimal. Increased out-of-field photon scatter from 18-MV IMRT carries out-of-field second cancer risks of approximately 0.2% over and above the 0.4% from 18-MV 3D-CRT. Greater photoneutron dose from 18-MV IMRT may result in further maximal, absolute increased risk to peripheral tissue of approximately 1.2% over 18-MV 3D-CRT. Out-of-field photon scatter remains comparable for the same modality irrespective of beam energy. Machine scatter (C+L) from 18 versus 6 MV is 1.2 times higher for IMRT and 1.8 times for 3D-CRT. It is 4 times higher for 6-MV IMRT versus 3D-CRT. Reduction in internal scatter with 18 MV versus 6 MV is 27% for 3D-CRT and 29% for IMRT. Compared with 6-MV 3D-CRT, 18-MV IMRT increases out-of-field second cancer risk by 0.2% from photons and adds 0.28-2.2% from neutrons. Conclusions: Out-of-field photon dose seems to be independent of beam energy for both techniques. Eighteen-megavolt IMRT increases out-of-field scatter 1.7-fold over 3D-CRT because of greater collimator scatter despite

  18. Gel dosimetry for conformal radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Gambarini, G [Department of Physics of the University and INFN, Milan (Italy)

    2005-07-01

    With the continuum development of conformal radio therapies, aimed at delivering high dose to tumor tissue and low dose to the healthy tissue around, the necessities has appeared of suitable improvement of dosimetry techniques giving the possibility of obtaining dose images to be compared with diagnostic images. Also if wide software has been developed for calculating dose distributions in the fields of various radiotherapy units, experimental verifications are necessary, in particular in the case of complex geometries in conformal radiotherapy. Gel dosimetry is a promising method for imaging the absorbed dose in tissue-equivalent phantoms, with the possibility of 3D reconstruction of the spatial dose distribution, with milli metric resolution. Optical imaging of gel dosimeters, based on visible light absorbance analysis, has shown to be a reliable technique for achieving dose distributions. (Author)

  19. One-dimensional phased array with mechanical motion for conformal ultrasound hyperthermia

    International Nuclear Information System (INIS)

    Ju, Kuen-Cheng; Chen, Yung-Yaw; Lin, Win-Li; Kuo, Te-Son

    2003-01-01

    This paper investigates the feasibility of conformal heating for external ultrasound hyperthermia by using a phased array transducer with mechanical motion. In this system, a one-dimensional phased array is arranged on a shaft and moves along the shaft, while dynamically focusing on the planning target volume (PTV) with numerous focal spots. To prevent overheating in the intervening tissue between the skin and the PTV, the shaft and the phased array are rotated together to enlarge the acoustical window. With the purpose of conformal heating, the power deposition of the PTV is constructed by combinations of the focal spots and an iterative gradient descent method is then used to determine an optimal set of power weightings for the focal spots. Different tumour shapes are evaluated and the simulation results demonstrate that the volume percentage of the PTV with temperatures higher than 43 deg. C is over 95%. The overheating volume outside the PTV is less than 25% of the PTV. This method provides good conformal heating for external ultrasound hyperthermia. The concept of combining electrical focusing and mechanical motion has the advantages of both enlarging the acoustic window and providing dynamic focusing ability, which is essential for successful conformal heating

  20. Conformity index for brain cancer patients

    International Nuclear Information System (INIS)

    Petkovska, Sonja; Tolevska, Cveta; Kraleva, Slavica; Petreska, Elena

    2010-01-01

    The purpose of this study is to present the level of conformity achieved by using 3D conformal radiotherapy for brain cancer patients. Conformity index is a helpful quantitative tool for assessing (evaluating) the quality of a treatment plan. Treatment plans made for ninety patients with brain tumor are worked on this paper. The patients are in supine position and immobilized with thermoplastic masks for the head. Computed tomography data sets with 5 mm scan thickness are used to create a 3D image. All structures of interest are contoured. In order to obtain an optimal dose distribution, treatment fields are fit around target volume with set-up margins of 7mm in each direction. The conformity index values are between 1.21 and 2.04. Value of 1.8 is exceeded in eighteen cases; nine of them are bigger than 1.9 and only three of them are above 2. The target volume for each of these extreme CI values is ideal covered (between 95% and 105% of the prescribed dose). The most acceptable conformity index value in this paper belongs to the plan with the lowest minimal dose (84.7%). It can be concluded that conformity index is necessary but not sufficient factor for assessing radiation treatment plan conformity. To be able to estimate the acceptability of some treatment plan in daily practice, additional information as minimal, maximal and mean dose into target volume, as well as health tissues coverage must be taken into account.(Author)

  1. Dosimetric comparison between conformational irradiation and helical tomo-therapy in supra-diaphragmatic Hodgkin disease in paediatrics; Comparaison dosimetrique entre l'irradiation conformationelle et la tomotherapie helicoidale dans la maladie de Hodgkin sus-diaphragmatique en pediatrie

    Energy Technology Data Exchange (ETDEWEB)

    Padovani, L.; Taright, N.; Muraracciole, X.; Nomikossof, N.; Capdeville, S.; Portal, T.; Cowen, D. [Assistance publique-hopitaux de Marseille (France)

    2011-10-15

    The authors report the comparison of dosimetry when using three-dimensional conformational radiotherapy or intensity-modulated conformational radiotherapy (IMRT) in the case of 13 children treated for a Hodgkin disease. The comparison is made in terms of previsional target volume (PTV) coverage and of doses received at the level of organs at risk. Coverage is almost the same for both techniques. Helical tomo-therapy allows the reduction of doses delivered to the heart, spine and lungs, including low doses (V5 and V10) while respecting an identical PTV coverage. This dose reduction could result in a reduction of toxicity on the long term, which is a major challenge for cured children. Short communication

  2. Advancing three-dimensional MEMS by complimentary laser micro manufacturing

    Science.gov (United States)

    Palmer, Jeremy A.; Williams, John D.; Lemp, Tom; Lehecka, Tom M.; Medina, Francisco; Wicker, Ryan B.

    2006-01-01

    This paper describes improvements that enable engineers to create three-dimensional MEMS in a variety of materials. It also provides a means for selectively adding three-dimensional, high aspect ratio features to pre-existing PMMA micro molds for subsequent LIGA processing. This complimentary method involves in situ construction of three-dimensional micro molds in a stand-alone configuration or directly adjacent to features formed by x-ray lithography. Three-dimensional micro molds are created by micro stereolithography (MSL), an additive rapid prototyping technology. Alternatively, three-dimensional features may be added by direct femtosecond laser micro machining. Parameters for optimal femtosecond laser micro machining of PMMA at 800 nanometers are presented. The technical discussion also includes strategies for enhancements in the context of material selection and post-process surface finish. This approach may lead to practical, cost-effective 3-D MEMS with the surface finish and throughput advantages of x-ray lithography. Accurate three-dimensional metal microstructures are demonstrated. Challenges remain in process planning for micro stereolithography and development of buried features following femtosecond laser micro machining.

  3. Effects of anatomic conformation on three-dimensional motion of the caudal lumbar and lumbosacral portions of the vertebral column of dogs.

    Science.gov (United States)

    Benninger, Monika I; Seiler, Gabriela S; Robinson, Leanne E; Ferguson, Stephen J; Bonél, Harald M; Busato, André R; Lang, Johann

    2006-01-01

    To determine the association between the 3-dimensional (3-D) motion pattern of the caudal lumbar and lumbosacral portions of the canine vertebral column and the morphology of vertebrae, facet joints, and intervertebral disks. Vertebral columns of 9 German Shepherd Dogs and 16 dogs of other breeds with similar body weights and body conditions. Different morphometric parameters of the vertebral column were assessed by computed tomography (CT) and magnetic resonance imaging. Anatomic conformation and the 3-D motion pattern were compared, and correlation coefficients were calculated. Total range of motion for flexion and extension was mainly associated with the facet joint angle, the facet joint angle difference between levels of the vertebral column in the transverse plane on CT images, disk height, and lever arm length. Motion is a complex process that is influenced by the entire 3-D conformation of the lumbar portion of the vertebral column. In vivo dynamic measurements of the 3-D motion pattern of the lumbar and lumbosacral portions of the vertebral column will be necessary to further assess biomechanics that could lead to disk degeneration in dogs.

  4. Use of the GEANT4 Monte Carlo to determine three-dimensional dose factors for radionuclide dosimetry

    International Nuclear Information System (INIS)

    Amato, Ernesto; Italiano, Antonio; Minutoli, Fabio; Baldari, Sergio

    2013-01-01

    The voxel-level dosimetry is the most simple and common approach to internal dosimetry of nonuniform distributions of activity within the human body. Aim of this work was to obtain the dose “S” factors (mGy/MBqs) at the voxel level for eight beta and beta–gamma emitting radionuclides commonly used in nuclear medicine diagnostic and therapeutic procedures. We developed a Monte Carlo simulation in GEANT4 of a region of soft tissue as defined by the ICRP, divided into 11×11×11 cubic voxels, 3 mm in side. The simulation used the parameterizations of the electromagnetic interaction optimized for low energy (EEDL, EPDL). The decay of each radionuclide ( 32 P, 90 Y, 99m Tc, 177 Lu, 131 I, 153 Sm, 186 Re, 188 Re) were simulated homogeneously distributed within the central voxel (0,0,0), and the energy deposited in the surrounding voxels was mediated on the 8 octants of the three dimensional space, for reasons of symmetry. The results obtained were compared with those available in the literature. While the iodine deviations remain within 16%, for phosphorus, a pure beta emitter, the agreement is very good for self-dose (0,0,0) and good for the dose to first neighbors, while differences are observed ranging from −60% to +100% for voxels far distant from the source. The existence of significant differences in the percentage calculation of the voxel S factors, especially for pure beta emitters such as 32 P or 90 Y, has already been highlighted by other authors. These data can usefully extend the dosimetric approach based on the voxel to other radionuclides not covered in the available literature

  5. Evaluation of homogeneity and dose conformity in IMRT planning in prostate radiotherapy; Avaliacao da homogeneidade e conformidade de dose em planejamentos de IMRT de prostata em radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Juliane S.; Leidens, Matheus; Estacio, Daniela R., E-mail: juliane.lopes@pucrs.br [Hospital Sao Lucas (PUC-RS), Porto Alegre, RS (Brazil). Servico de Radioterapia; Razera, Ricardo A.Z.; Streck, Elaine E.; Silva, Ana M.M. da [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Faculdade de Fisica

    2015-12-15

    The goal of this study was to evaluate the dose distribution homogeneity and conformity of radiation therapy plans of prostate cancer using IMRT. Data from 34 treatment plans of Hospital Sao Lucas of PUCRS, where those plans were executed, were retrospectively analyzed. All of them were done with 6MV X-rays from a linear accelerator CLINAC IX, and the prescription doses varied between 60 and 74 Gy. Analyses showing the homogeneity and conformity indices for the dose distribution of those plans were made. During these analyses, some comparisons with the traditional radiation therapy planning technic, the 3D-CRT, were discussed. The results showed that there is no correlation between the prescribed dose and the homogeneity and conformity indices, indicating that IMRT works very well even for higher doses. Furthermore, a comparison between the results obtained and the recommendations of ICRU 83 was carried out. It has also been observed that the indices were really close to the ideal values. 82.4% of the cases showed a difference below 5% of the ideal value for the index of conformity, and 88.2% showed a difference below 10% for the homogeneity index. Concluding, it is possible to confirm the quality of the analyzed radiation therapy plans of prostate cancer using IMRT. (author)

  6. High energy physics signatures from inflation and conformal symmetry of de Sitter

    International Nuclear Information System (INIS)

    Kehagias, A.; Riotto, A.

    2015-01-01

    During inflation, the geometry of spacetime is described by a (quasi-)de Sitter phase. Inflationary observables are determined by the underlying (softly broken) de Sitter isometry group SO(1, 4) which acts like a conformal group on R 3 : when the fluctuations are on super-Hubble scales, the correlators of the scalar fields are constrained by conformal invariance. Heavy fields with mass m larger than the Hubble rate H correspond to operators with imaginary dimensions in the dual Euclidean three-dimensional conformal field theory. By making use of the dS/CFT correspondence we show that, besides the Boltzmann suppression expected from the thermal properties of de Sitter space, the generic effect of heavy fields in the inflationary correlators of the light fields is to introduce power-law suppressed corrections of the form O(H 2 / m 2 ). This can be seen, for instance, at the level of the four-point correlator for which we provide the correction due to a massive scalar field exchange. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. High-speed three-dimensional plasma temperature determination of axially symmetric free-burning arcs

    International Nuclear Information System (INIS)

    Bachmann, B; Ekkert, K; Bachmann, J-P; Marques, J-L; Schein, J; Kozakov, R; Gött, G; Schöpp, H; Uhrlandt, D

    2013-01-01

    In this paper we introduce an experimental technique that allows for high-speed, three-dimensional determination of electron density and temperature in axially symmetric free-burning arcs. Optical filters with narrow spectral bands of 487.5–488.5 nm and 689–699 nm are utilized to gain two-dimensional spectral information of a free-burning argon tungsten inert gas arc. A setup of mirrors allows one to image identical arc sections of the two spectral bands onto a single camera chip. Two-different Abel inversion algorithms have been developed to reconstruct the original radial distribution of emission coefficients detected with each spectral window and to confirm the results. With the assumption of local thermodynamic equilibrium we calculate emission coefficients as a function of temperature by application of the Saha equation, the ideal gas law, the quasineutral gas condition and the NIST compilation of spectral lines. Ratios of calculated emission coefficients are compared with measured ones yielding local plasma temperatures. In the case of axial symmetry the three-dimensional plasma temperature distributions have been determined at dc currents of 100, 125, 150 and 200 A yielding temperatures up to 20000 K in the hot cathode region. These measurements have been validated by four different techniques utilizing a high-resolution spectrometer at different positions in the plasma. Plasma temperatures show good agreement throughout the different methods. Additionally spatially resolved transient plasma temperatures have been measured of a dc pulsed process employing a high-speed frame rate of 33000 frames per second showing the modulation of the arc isothermals with time and providing information about the sensitivity of the experimental approach. (paper)

  8. Introduction to two dimensional conformal and superconformal field theory

    International Nuclear Information System (INIS)

    Shenker, S.H.

    1986-01-01

    Some of the basic properties of conformal and superconformal field theories in two dimensions are discussed in connection with the string and superstring theories built from them. In the first lecture the stress-energy tensor, the Virasoro algebra, highest weight states, primary fields, operator products coefficients, bootstrap ideas, and unitary and degenerate representations of the Virasoro algebra are discussed. In the second lecture the basic structure of superconformal two dimensional field theory is sketched and then the Ramond Neveu-Schwarz formulation of the superstring is described. Some of the issues involved in constructing the fermion vertex in this formalism are discussed

  9. Three-dimensional carbon nanotube networks with a supported nickel oxide nanonet for high-performance supercapacitors.

    Science.gov (United States)

    Wu, Mao-Sung; Zheng, Yo-Ru; Lin, Guan-Wei

    2014-08-04

    A three-dimensional porous carbon nanotube film with a supported NiO nanonet was prepared by simple electrophoretic deposition and hydrothermal synthesis, which could deliver a high specific capacitance of 1511 F g(-1) at a high discharge current of 50 A g(-1) due to the significantly improved transport of the electrolyte and electrons.

  10. One loop partition function of six dimensional conformal gravity using heat kernel on AdS

    Energy Technology Data Exchange (ETDEWEB)

    Lovreković, Iva [Institute for Theoretical Physics, Technische Universität Wien,Wiedner Hauptstrasse 8-10/136, A-1040 Vienna (Austria)

    2016-10-13

    We compute the heat kernel for the Laplacians of symmetric transverse traceless fields of arbitrary spin on the AdS background in even number of dimensions using the group theoretic approach introduced in http://dx.doi.org/10.1007/JHEP11(2011)010 and apply it on the partition function of six dimensional conformal gravity. The obtained partition function consists of the Einstein gravity, conformal ghost and two modes that contain mass.

  11. Vibrational spectra and thermal rectification in three-dimensional anharmonic lattices

    International Nuclear Information System (INIS)

    Lan Jinghua; Li Baowen

    2007-01-01

    We study thermal rectification in a three-dimensional model consisting of two segments of anharmonic lattices. One segment consists of layers of harmonic oscillator arrays coupled to a substrate potential, which is a three-dimensional Frenkel-Kontorova model, and the other segment is a three-dimensional Fermi-Pasta-Ulam model. We study the vibrational bands of the two lattices analytically and numerically, and find that, by choosing the system parameters properly, the rectification can be as high as a few thousands, which is high enough to be observed in experiment. Possible experiments in nanostructures are discussed

  12. Three-dimensional intrafractional internal target motions in accelerated partial breast irradiation using three-dimensional conformal external beam radiotherapy.

    Science.gov (United States)

    Hirata, Kimiko; Yoshimura, Michio; Mukumoto, Nobutaka; Nakamura, Mitsuhiro; Inoue, Minoru; Sasaki, Makoto; Fujimoto, Takahiro; Yano, Shinsuke; Nakata, Manabu; Mizowaki, Takashi; Hiraoka, Masahiro

    2017-07-01

    We evaluated three-dimensional intrafractional target motion, divided into respiratory-induced motion and baseline drift, in accelerated partial breast irradiation (APBI). Paired fluoroscopic images were acquired simultaneously using orthogonal kV X-ray imaging systems at pre- and post-treatment for 23 patients who underwent APBI with external beam radiotherapy. The internal target motion was calculated from the surgical clips placed around the tumour cavity. The peak-to-peak respiratory-induced motions ranged from 0.6 to 1.5mm in all directions. A systematic baseline drift of 1.5mm towards the posterior direction and a random baseline drift of 0.3mm in the lateral-medial and cranial-caudal directions were observed. The baseline for an outer tumour cavity drifted towards the lateral and posterior directions, and that for an upper tumour cavity drifted towards the cranial direction. Moderate correlations were observed between the posterior baseline drift and the patients' physical characteristics. The posterior margin for intrafractional uncertainties was larger than 5mm in patients with greater fat thickness due to the baseline drift. The magnitude of the intrafractional motion was not uniform according to the direction, patients' physical characteristics, or tumour cavity location due to the baseline drift. Therefore, the intrafractional systematic movement should be properly managed. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Preparation of wholemount mouse intestine for high-resolution three-dimensional imaging using two-photon microscopy.

    Science.gov (United States)

    Appleton, P L; Quyn, A J; Swift, S; Näthke, I

    2009-05-01

    Visualizing overall tissue architecture in three dimensions is fundamental for validating and integrating biochemical, cell biological and visual data from less complex systems such as cultured cells. Here, we describe a method to generate high-resolution three-dimensional image data of intact mouse gut tissue. Regions of highest interest lie between 50 and 200 mum within this tissue. The quality and usefulness of three-dimensional image data of tissue with such depth is limited owing to problems associated with scattered light, photobleaching and spherical aberration. Furthermore, the highest-quality oil-immersion lenses are designed to work at a maximum distance of image at high-resolution deep within tissue. We show that manipulating the refractive index of the mounting media and decreasing sample opacity greatly improves image quality such that the limiting factor for a standard, inverted multi-photon microscope is determined by the working distance of the objective as opposed to detectable fluorescence. This method negates the need for mechanical sectioning of tissue and enables the routine generation of high-quality, quantitative image data that can significantly advance our understanding of tissue architecture and physiology.

  14. A high-resolution map of the three-dimensional chromatin interactome in human cells.

    Science.gov (United States)

    Jin, Fulai; Li, Yan; Dixon, Jesse R; Selvaraj, Siddarth; Ye, Zhen; Lee, Ah Young; Yen, Chia-An; Schmitt, Anthony D; Espinoza, Celso A; Ren, Bing

    2013-11-14

    A large number of cis-regulatory sequences have been annotated in the human genome, but defining their target genes remains a challenge. One strategy is to identify the long-range looping interactions at these elements with the use of chromosome conformation capture (3C)-based techniques. However, previous studies lack either the resolution or coverage to permit a whole-genome, unbiased view of chromatin interactions. Here we report a comprehensive chromatin interaction map generated in human fibroblasts using a genome-wide 3C analysis method (Hi-C). We determined over one million long-range chromatin interactions at 5-10-kb resolution, and uncovered general principles of chromatin organization at different types of genomic features. We also characterized the dynamics of promoter-enhancer contacts after TNF-α signalling in these cells. Unexpectedly, we found that TNF-α-responsive enhancers are already in contact with their target promoters before signalling. Such pre-existing chromatin looping, which also exists in other cell types with different extracellular signalling, is a strong predictor of gene induction. Our observations suggest that the three-dimensional chromatin landscape, once established in a particular cell type, is relatively stable and could influence the selection or activation of target genes by a ubiquitous transcription activator in a cell-specific manner.

  15. Predictors for Rectal and Intestinal Acute Toxicities During Prostate Cancer High-Dose 3D-CRT: Results of a Prospective Multicenter Study

    International Nuclear Information System (INIS)

    Vavassori, Vittorio; Fiorino, Claudio; Rancati, Tiziana; Magli, Alessandro; Fellin, Gianni; Baccolini, Michela; Bianchi, Carla; Cagna, Emanuela; Mauro, Flora A.; Monti, Angelo F.; Munoz, Fernando; Stasi, Michele; Franzone, Paola; Valdagni, Riccardo

    2007-01-01

    Purpose: To find predictors for rectal and intestinal acute toxicity in patients with prostate cancer treated with ≥70 Gy conformal radiotherapy. Methods and Materials: Between July 2002 and March 2004, 1,132 patients were entered into a cooperative study (AIROPROS01-02). Toxicity was scored using the Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer scale and by considering the changes (before and after treatment) of the scores of a self-administered questionnaire on rectal/intestinal toxicity. The correlation with a number of parameters was assessed by univariate and multivariate analyses. Concerning the questionnaire, only moderate/severe complications were considered. Results: Of 1,132 patients, 1,123 were evaluable. Of these patients, 375, 265, and 28 had Grade 1, 2, and 3 Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer toxicity, respectively. The mean rectal dose was the most predictive parameter (p = 0.0004; odds ratio, 1.035) for Grade 2 or worse toxicity, and the use of anticoagulants/antiaggregants (p 0.02; odds ratio, 0.63) and hormonal therapy (p = 0.04, odds ratio, 0.65) were protective. The questionnaire-based scoring revealed that a greater mean rectal dose was associated with a greater risk of bleeding; larger irradiated volumes were associated with frequency, tenesmus, incontinence, and bleeding; hormonal therapy was protective against frequency and tenesmus; hemorrhoids were associated with a greater risk of tenesmus and bleeding; and diabetes associated highly with diarrhea. Conclusion: The mean rectal dose correlated with acute rectal/intestinal toxicity in three-dimensional conformal radiotherapy for prostate cancer, and hormonal therapy and the use of anticoagulants/antiaggregants were protective. According to the moderate/severe injury scores on the self-assessed questionnaire, several clinical and dose-volume parameters were independently predictive for

  16. Prognosis comparison of three-dimensional conformal radiotherapy/intensity modulated radiation therapy for esophageal carcinoma with local regional lymph node metastasis

    International Nuclear Information System (INIS)

    Wang Yuxiang; Wang Jun; Wang Yi; Tian Dandan; Yang Jie; Zhu Shuchai

    2011-01-01

    Objective: To explore the prognosis and related factor of esophageal carcinoma with locoregional lymph node metastasis (N 1 ) treated with three-dimensional conformal radiotherapy (3DCRT) or intensity modulated radiation therapy (IMRT). Methods: From January 2001 to December 2008, 60 patients of esophageal carcinoma with local regional lymph node metastasis were treated with 3DCRT and 52 with IMRT. For all patients,dose of tumor was 56 - 70 Gy/28 - 35 fraction/5.6 - 7.0 weeks. Among them, 58 cases was treated with chemotherapy including cisplatin and 5-fluorouracil; 40 with concurrent chemoradiotherapy and 18 with sequential radiotherapy and chemotherapy. Results: After radiotherapy,the total efficiency rate was 98.2%, 96.7% in 3DCRT and 100% in IMRT (χ 2 =1.77, P =0.184). The follow-up rate was 99.1%. The number of patients completed follow-up were 68 and 53, respectively at 2-year and 3-year. The 1 and 3-year overall survival rates were 62.5%, 23.7%, respectively; the median survival time was 17 months. The 1 and 3-year survival rates and median were 52%, 19% and 12.4 months in 3DCRT and 75%, 40% and 17 months in IMRT, respectively (χ 2 =4.74, P =0.030). The 1 and 3-year free-recurrence survival rates were 64%, 45% in 3DCRT and 72%, 59% in IMRT (χ 2 =2.27, P =0.132), respectively. With univariate analysis, for female, ages ≤ 65, tumor located in cervical and upper-thoracic, >5 cm lesion length in barium esophagogram, ≤4 cm the largest diameter of lesion in CT scanning image, T 4 stage, or semiliquid or liquid diet before radiotherapy, survival rate were higher in IMRT than in 3DCRT group (χ 2 =4.63, 5.56, 7.19, 5.08, 4.43, 4.48, 8.25; P=0.031, 0.018, 0.007, 0.025, 0.035, 0.034, 0.004, respectively); but for male, ages > 65, tumor located in middle and lower-thoracic, ≤5 cm lesion length in barium esophagogram, >4 cm the largest diameter of lesion in CT scanning image, T 1-3 stage, or normal diet before radiotherapy, chemotherapy and dose of radiotherapy

  17. Conformal technique dose escalation in prostate cancer: improved cancer control with higher doses in patients with pretreatment PSA {>=} 10 ngm/ml

    Energy Technology Data Exchange (ETDEWEB)

    Hanks, G E; Lee, W R; Hanlon, A L; Kaplan, E; Epstein, B; Schultheiss, T

    1995-07-01

    Purpose: Single institutions and an NCI supported group of institutions have been investigating the value of dose escalation in patients with prostate cancer treated by conformal treatment techniques. Improvement in morbidity has been previously established, while this report identifies the pretreatment PSA level subgroups of patients who benefitted in cancer control from higher dose. Materials and Methods: We report actuarial bNED survival rates for 375 consecutive patients with known pretreatment PSA levels treated with conformal technique between 5/89 and 12/93. The whole pelvis was treated to 45 Gy in 25 fractions in all T2C,3, all Gleason 8, 9, 10 and all patients with pretreatment PSA {>=}20. The prostate {+-} seminal vesicles was boosted at 2.1 Gy/day to the center of the prostate to 65-79 Gy (65-69 N=50), 70-72.49 N=94, 72.5-74.9 N=82, 75-77.49 N=129 and {>=}77.5 N=20). The median followup is 21 mos with a range of 3 to 67 mos. The highest dose patients have the least followup, reducing the impact of the highest dose levels at this time. Patients are analyzed for the entire group divided at 71 Gy and at 73 Gy calculated at the center of the prostate. Each dose group is then subdivided by pretreatment PSA levels <10, 10-19.9, and {>=}20 ngm/ml and dose levels are compared within pretreatment PSA level group. bNED failure is defined as PSA {>=}1.5 ngm/ml and rising on two consecutive values. Results: Table 1 shows the bNED survival rates at 24 and 36 mos for all patients and the three pretreatment PSA level groups. For all patients pooled, there is an overall advantage to using doses {>=}71 Gy (64% vs 85% at 36 mo, p=.006) and {>=}73 Gy (71% vs 86% at 36 mo, p=.07). The subgroup of PSA <10 ngm/ml, however, shows no benefit in bNED survival when using doses over 71 Gy (90% vs 93% at 36 mo) or 73 Gy (91 vs 94% at 36 mo). The subgroup PSA 10 ngm/ml to 19.9 ngm/ml shows improved cancer control when using doses over 71 Gy (61% vs 88% at 36 mo, p=.03) and over 73

  18. Three dimensional canonical transformations

    International Nuclear Information System (INIS)

    Tegmen, A.

    2010-01-01

    A generic construction of canonical transformations is given in three-dimensional phase spaces on which Nambu bracket is imposed. First, the canonical transformations are defined as based on cannonade transformations. Second, it is shown that determination of the generating functions and the transformation itself for given generating function is possible by solving correspondent Pfaffian differential equations. Generating functions of type are introduced and all of them are listed. Infinitesimal canonical transformations are also discussed as the complementary subject. Finally, it is shown that decomposition of canonical transformations is also possible in three-dimensional phase spaces as in the usual two-dimensional ones.

  19. Three Dimensional Polarimetric Neutron Tomography of Magnetic Fields

    DEFF Research Database (Denmark)

    Sales, Morten; Strobl, Markus; Shinohara, Takenao

    2018-01-01

    Through the use of Time-of-Flight Three Dimensional Polarimetric Neutron Tomography (ToF 3DPNT) we have for the first time successfully demonstrated a technique capable of measuring and reconstructing three dimensional magnetic field strengths and directions unobtrusively and non-destructively wi......Through the use of Time-of-Flight Three Dimensional Polarimetric Neutron Tomography (ToF 3DPNT) we have for the first time successfully demonstrated a technique capable of measuring and reconstructing three dimensional magnetic field strengths and directions unobtrusively and non...... and reconstructed, thereby providing the proof-of-principle of a technique able to reveal hitherto unobtainable information on the magnetic fields in the bulk of materials and devices, due to a high degree of penetration into many materials, including metals, and the sensitivity of neutron polarisation to magnetic...... fields. The technique puts the potential of the ToF time structure of pulsed neutron sources to full use in order to optimise the recorded information quality and reduce measurement time....

  20. Study on a Novel Gelled Foam for Conformance Control in High Temperature and High Salinity Reservoirs

    Directory of Open Access Journals (Sweden)

    Tong Li

    2018-05-01

    Full Text Available A novel gelled foam for conformance control was investigated for its ability to enhance oil recovery (EOR in high temperature and high salinity reservoirs. The formulation optimization, foaming performance, and core flooding performance of the gelled foam were systematically evaluated under harsh reservoir conditions. The gelled foam formulation was optimized with 0.4% polymer (hydrolyzed polyacrylamide; HPAM, 0.06% cross-linker (phenolic and 0.2% foaming agent (sulphobetaine; SB. The addition of the gel improved the stability of the foam system by 3.8 times that of traditional foam. A stabilization mechanism in the gelled foam was proposed to describe the stabilization process of the foam film. The uniformly distributed three-dimensional network structure of the gel provided a thick protective layer for the foam system that maintained the stability of the foam and improved the strength and thickness of the liquid film. The gelled foam exhibited good formation adaptability, profile control, and EOR performance. The foam flowed into the high permeability layer, plugged the dominant channel, and increased the swept volume. Oil recovery was enhanced by 29.4% under harsh high -temperature and high salinity conditions.

  1. Confidence in Assessment of Lumbar Spondylolysis Using Three-Dimensional Volumetric T2-Weighted MRI Compared With Limited Field of View, Decreased-Dose CT.

    Science.gov (United States)

    Delavan, Joshua Adam; Stence, Nicholas V; Mirsky, David M; Gralla, Jane; Fadell, Michael F

    2016-07-01

    Limited z-axis-coverage computed tomography (CT) to evaluate for pediatric lumbar spondylolysis, altering the technique such that the dose to the patient is comparable or lower than radiographs, is currently used at our institution. The objective of the study was to determine whether volumetric 3-dimensional fast spin echo magnetic resonance imaging (3D MRI) can provide equal or greater diagnostic accuracy compared with limited CT in the diagnosis of pediatric lumbar spondylolysis without ionizing radiation. Volumetric 3D MRI can provide equal or greater diagnostic accuracy compared with low-dose CT for pediatric lumbar spondylolysis without ionizing radiation. Clinical review. Level 2. Three pediatric neuroradiologists evaluated 2-dimensional (2D) MRI, 2D + 3D MRI, and limited CT examinations in 42 pediatric patients who obtained imaging for low back pain and suspected spondylolysis. As there is no gold standard for the diagnosis of spondylolysis besides surgery, interobserver agreement and degree of confidence were compared to determine which modality is preferable. Decreased-dose CT provided a greater level of agreement than 2D MRI and 2D + 3D MRI. The kappa for rater agreement with 2D MRI, 2D + 3D MRI, and CT was 0.19, 0.32, and 1.0, respectively. All raters agreed in 31%, 40%, and 100% of cases with 2D MRI, 2D + 3D MRI, and CT. Lack of confidence was significantly lower with CT (0%) than with 2D MRI (30%) and 2D + 3D MRI (25%). For diagnosing spondylolysis, radiologist agreement and confidence trended toward improvement with the addition of a volumetric 3D MRI sequence to standard 2D MRI sequences compared with 2D MRI alone; however, agreement and confidence remain significantly greater using decreased-dose CT when compared with either MRI acquisition. Decreased-dose CT of the lumbar spine remains the optimal examination to confirm a high suspicion of spondylolysis, with dose essentially equivalent to radiographs. If clinical symptoms are not classic for

  2. Development of a three-dimensionally movable phantom system for dosimetric verifications

    International Nuclear Information System (INIS)

    Nakayama, Hiroshi; Mizowaki, Takashi; Narita, Yuichiro; Kawada, Noriyuki; Takahashi, Kunio; Mihara, Kazumasa; Hiraoka, Masahiro

    2008-01-01

    The authors developed a three-dimensionally movable phantom system (3D movable phantom system) which can reproduce three-dimensional movements to experimentally verify the impact of radiotherapy treatment-related movements on dose distribution. The phantom system consists of three integrated components: a three-dimensional driving mechanism (3D driving mechanism), computer control system, and phantoms for film dosimetry. The 3D driving mechanism is a quintessential part of this system. It is composed of three linear-motion tables (single-axis robots) which are joined orthogonally to each other. This mechanism has a motion range of 100 mm, with a maximum velocity of 200 mm/s in each dimension, and 3D motion ability of arbitrary patterns. These attributes are sufficient to reproduce almost all organ movements. The positional accuracy of this 3D movable phantom system in a state of geostationary is less than 0.1 mm. The maximum error in terms of the absolute position on movement was 0.56 mm. The positional reappearance error on movement was up to 0.23 mm. The observed fluctuation of time was 0.012 s in the cycle of 4.5 s of oscillation. These results suggested that the 3D movable phantom system exhibited a sufficient level of accuracy in terms of geometry and timing to reproduce interfractional organ movement or setup errors in order to assess the influence of these errors on high-precision radiotherapy such as stereotactic irradiation and intensity-modulated radiotherapy. In addition, the authors 3D movable phantom system will also be useful in evaluating the adequacy and efficacy of new treatment techniques such as gating or tracking radiotherapy

  3. Three-dimensional reacting shock–bubble interaction

    NARCIS (Netherlands)

    Diegelmann, Felix; Hickel, S.; Adams, Nikolaus A.

    2017-01-01

    We investigate a reacting shock–bubble interaction through three-dimensional numerical simulations with detailed chemistry. The convex shape of the bubble focuses the shock and generates regions of high pressure and temperature, which are sufficient to ignite the diluted stoichiometric

  4. Three-dimensional photon radiotherapy planning for laryngeal and hypopharyngeal tumours

    International Nuclear Information System (INIS)

    Esik, O.; Schlegel, W.; Doll, J.; Nemeth, G.; Lorenz, W.J.; Weil Emil Korhaz-Rendeloeintezet, Budapest; Deutsches Krebsforschungszentrum, Heidelberg

    1990-01-01

    Three-dimensional absorbed dose distributions have been computed for high-energy photon radiation therapy of laryngeal and hypopharyngeal cancers, using a coaxial pair of opposing lateral beams in fixed positions. Treatment plans obtained under various conditions of irradiation are analyzed and compared for a cobalt-60 gamma unit (GAMMATRON S80, Siemens), photon beams from a 6 MV (CLINAC 1800, VARIAN), an 8 MV (SATURNE, CGR) and a 15 MV (MEVATRON 77, Siemens) linear accelerator. Using open fields a somewhat non-uniform and partly insufficient dose in target volume of interest is obtained with all treatment units if sufficient protection of the spinal cord is provided. The X-ray plans are somewhat superior to the cobalt-60 ones. Depending on the quantum energy and wedge isodose angle, wedging only slightly improves or sometimes moderately decreases the homogeneity of the dose in the target volume. According to these small and/or controversial effects of wedges their application seems unnecessary and/or non-convenient. Simulations show that extreme care is needed in positioning the isocentre: An accuracy of ±3 mm is required in the median sagittal plane. (orig.)

  5. Three-dimensional microbubble streaming flows

    Science.gov (United States)

    Rallabandi, Bhargav; Marin, Alvaro; Rossi, Massimiliano; Kaehler, Christian; Hilgenfeldt, Sascha

    2014-11-01

    Streaming due to acoustically excited bubbles has been used successfully for applications such as size-sorting, trapping and focusing of particles, as well as fluid mixing. Many of these applications involve the precise control of particle trajectories, typically achieved using cylindrical bubbles, which establish planar flows. Using astigmatic particle tracking velocimetry (APTV), we show that, while this two-dimensional picture is a useful description of the flow over short times, a systematic three-dimensional flow structure is evident over long time scales. We demonstrate that this long-time three-dimensional fluid motion can be understood through asymptotic theory, superimposing secondary axial flows (induced by boundary conditions at the device walls) onto the two-dimensional description. This leads to a general framework that describes three-dimensional flows in confined microstreaming systems, guiding the design of applications that profit from minimizing or maximizing these effects.

  6. Facile fabrication of the porous three-dimensional regenerated silk fibroin scaffolds

    International Nuclear Information System (INIS)

    Cao, Zhengbing; Wen, Jianchuan; Yao, Jinrong; Chen, Xin; Ni, Yusu; Shao, Zhengzhong

    2013-01-01

    In the present work, we report a new facile method to fabricate porous three-dimensional regenerated silk fibroin (RSF) scaffolds through n-butanol- and freezing-induced conformation transition and phase separation. The effects of RSF concentration, freezing temperature and n-butanol addition on the microstructure, the secondary structures of silk fibroin and apparent mechanical properties of the RSF scaffolds were investigated by SEM, 13 C CP-MAS NMR spectra and mechanical testing, respectively. By adjusting the RSF concentration and n-butanol addition, the pore size of the scaffold could be controlled in the range from of 10 μm to 350 μm with 84%–98% of porosity. The tensile strength of the wet scaffold reached the maximum of 755.2 ± 33.6 kPa when the concentration of RSF solution was increased to 15% w/w. Moreover, post-treatment with ethanol further induced conformation transition of RSF from random coil or helix to β-sheet. The porous scaffolds prepared by this facile and energy-saving method with good biocompatibility will have great potential for application in tissue engineering. Highlights: • A new facile and energy-saving method to fabricate porous silk fibroin scaffolds; • Freeze-drying step (a typical high energy consuming process) is unnecessary; • Morphology and mechanical properties of scaffolds were easily controlled; • Ethanol post-treatment can be used to tune the degradation behavior

  7. Low-resistance gateless high electron mobility transistors using three-dimensional inverted pyramidal AlGaN/GaN surfaces

    International Nuclear Information System (INIS)

    So, Hongyun; Senesky, Debbie G.

    2016-01-01

    In this letter, three-dimensional gateless AlGaN/GaN high electron mobility transistors (HEMTs) were demonstrated with 54% reduction in electrical resistance and 73% increase in surface area compared with conventional gateless HEMTs on planar substrates. Inverted pyramidal AlGaN/GaN surfaces were microfabricated using potassium hydroxide etched silicon with exposed (111) surfaces and metal-organic chemical vapor deposition of coherent AlGaN/GaN thin films. In addition, electrical characterization of the devices showed that a combination of series and parallel connections of the highly conductive two-dimensional electron gas along the pyramidal geometry resulted in a significant reduction in electrical resistance at both room and high temperatures (up to 300 °C). This three-dimensional HEMT architecture can be leveraged to realize low-power and reliable power electronics, as well as harsh environment sensors with increased surface area

  8. Low-resistance gateless high electron mobility transistors using three-dimensional inverted pyramidal AlGaN/GaN surfaces

    Energy Technology Data Exchange (ETDEWEB)

    So, Hongyun, E-mail: hyso@stanford.edu [Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305 (United States); Senesky, Debbie G. [Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305 (United States); Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2016-01-04

    In this letter, three-dimensional gateless AlGaN/GaN high electron mobility transistors (HEMTs) were demonstrated with 54% reduction in electrical resistance and 73% increase in surface area compared with conventional gateless HEMTs on planar substrates. Inverted pyramidal AlGaN/GaN surfaces were microfabricated using potassium hydroxide etched silicon with exposed (111) surfaces and metal-organic chemical vapor deposition of coherent AlGaN/GaN thin films. In addition, electrical characterization of the devices showed that a combination of series and parallel connections of the highly conductive two-dimensional electron gas along the pyramidal geometry resulted in a significant reduction in electrical resistance at both room and high temperatures (up to 300 °C). This three-dimensional HEMT architecture can be leveraged to realize low-power and reliable power electronics, as well as harsh environment sensors with increased surface area.

  9. Cooperative simulation of lithography and topography for three-dimensional high-aspect-ratio etching

    Science.gov (United States)

    Ichikawa, Takashi; Yagisawa, Takashi; Furukawa, Shinichi; Taguchi, Takafumi; Nojima, Shigeki; Murakami, Sadatoshi; Tamaoki, Naoki

    2018-06-01

    A topography simulation of high-aspect-ratio etching considering transports of ions and neutrals is performed, and the mechanism of reactive ion etching (RIE) residues in three-dimensional corner patterns is revealed. Limited ion flux and CF2 diffusion from the wide space of the corner is found to have an effect on the RIE residues. Cooperative simulation of lithography and topography is used to solve the RIE residue problem.

  10. [Application Progress of Three-dimensional Laser Scanning Technology in Medical Surface Mapping].

    Science.gov (United States)

    Zhang, Yonghong; Hou, He; Han, Yuchuan; Wang, Ning; Zhang, Ying; Zhu, Xianfeng; Wang, Mingshi

    2016-04-01

    The booming three-dimensional laser scanning technology can efficiently and effectively get spatial three-dimensional coordinates of the detected object surface and reconstruct the image at high speed,high precision and large capacity of information.Non-radiation,non-contact and the ability of visualization make it increasingly popular in three-dimensional surface medical mapping.This paper reviews the applications and developments of three-dimensional laser scanning technology in medical field,especially in stomatology,plastic surgery and orthopedics.Furthermore,the paper also discusses the application prospects in the future as well as the biomedical engineering problems it would encounter with.

  11. Fully three-dimensional image reconstruction in radiology and nuclear medicine. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    The proceedings of the meeting on ''fully three-dimensional image reconstruction in radiology and nuclear medicine'' covers contributions on the following topics: CT imaging, PET imaging, fidelity; iterative and few-view CT, CT-analytical; PET/SPECT Compton analytical; doses - spectral methods; phase contrast; compressed sensing- sparse reconstruction; special issues; motion - cardiac.

  12. Use of the GEANT4 Monte Carlo to determine three-dimensional dose factors for radionuclide dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Amato, Ernesto, E-mail: eamato@unime.it [University of Messina, Department of Biomedical Sciences and of Morphologic and Functional Imaging, Section of Radiological Sciences (Italy); Italiano, Antonio [INFN – Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Messina (Italy); Minutoli, Fabio; Baldari, Sergio [University of Messina, Department of Biomedical Sciences and of Morphologic and Functional Imaging, Section of Radiological Sciences (Italy)

    2013-04-21

    The voxel-level dosimetry is the most simple and common approach to internal dosimetry of nonuniform distributions of activity within the human body. Aim of this work was to obtain the dose “S” factors (mGy/MBqs) at the voxel level for eight beta and beta–gamma emitting radionuclides commonly used in nuclear medicine diagnostic and therapeutic procedures. We developed a Monte Carlo simulation in GEANT4 of a region of soft tissue as defined by the ICRP, divided into 11×11×11 cubic voxels, 3 mm in side. The simulation used the parameterizations of the electromagnetic interaction optimized for low energy (EEDL, EPDL). The decay of each radionuclide ({sup 32}P, {sup 90}Y, {sup 99m}Tc, {sup 177}Lu, {sup 131}I, {sup 153}Sm, {sup 186}Re, {sup 188}Re) were simulated homogeneously distributed within the central voxel (0,0,0), and the energy deposited in the surrounding voxels was mediated on the 8 octants of the three dimensional space, for reasons of symmetry. The results obtained were compared with those available in the literature. While the iodine deviations remain within 16%, for phosphorus, a pure beta emitter, the agreement is very good for self-dose (0,0,0) and good for the dose to first neighbors, while differences are observed ranging from −60% to +100% for voxels far distant from the source. The existence of significant differences in the percentage calculation of the voxel S factors, especially for pure beta emitters such as {sup 32}P or {sup 90}Y, has already been highlighted by other authors. These data can usefully extend the dosimetric approach based on the voxel to other radionuclides not covered in the available literature.

  13. BRST structure of two dimensional conformal field theories

    International Nuclear Information System (INIS)

    Rivelles, V.O.

    1987-09-01

    We present a procedure to obtain the BRST charge for the representations of the Virassoro algebra. For C ≤ 1 the BRST charge has in general terms containing products of more than three ghosts. It is nilpotent for any allowed value of the central charge and conformal weight of the representation. (Author) [pt

  14. Diffraction limited focusing with controllable arbitrary three-dimensional polarization

    International Nuclear Information System (INIS)

    Chen, Weibin; Zhan, Qiwen

    2010-01-01

    We propose a new approach that enables full control over the three-dimensional state of polarization and the field distribution near the focus of a high numerical aperture objective lens. By combining the electric dipole radiation and a vectorial diffraction method, the input field at the pupil plane for generating arbitrary three-dimensionally oriented linear polarization at the focal point with a diffraction limited spot size is found analytically by solving the inverse problem. Arbitrary three-dimensional elliptical polarization can be obtained by introducing a second electric dipole oriented in the orthogonal plane with appropriate amplitude and phase differences

  15. Development of three-dimensional neoclassical transport simulation code with high performance Fortran on a vector-parallel computer

    International Nuclear Information System (INIS)

    Satake, Shinsuke; Okamoto, Masao; Nakajima, Noriyoshi; Takamaru, Hisanori

    2005-11-01

    A neoclassical transport simulation code (FORTEC-3D) applicable to three-dimensional configurations has been developed using High Performance Fortran (HPF). Adoption of computing techniques for parallelization and a hybrid simulation model to the δf Monte-Carlo method transport simulation, including non-local transport effects in three-dimensional configurations, makes it possible to simulate the dynamism of global, non-local transport phenomena with a self-consistent radial electric field within a reasonable computation time. In this paper, development of the transport code using HPF is reported. Optimization techniques in order to achieve both high vectorization and parallelization efficiency, adoption of a parallel random number generator, and also benchmark results, are shown. (author)

  16. A secretome analysis reveals that PPARα is upregulated by fractionated-dose γ-irradiation in three-dimensional keratinocyte cultures

    International Nuclear Information System (INIS)

    Lee, Jee Yong; Kim, Hyun Ji; Yi, Jae Youn

    2016-01-01

    A three-dimensional (3D) environment composed of properly interconnected and differentiated cells that allows communication and cooperation among cells via secreted molecules would be expected to more accurately reflect cellular responses. Here, we investigated γ-irradiation-induced changes in the secretome of 3D-cultured keratinocytes. An analysis of keratinocyte secretome profiles following fractionated-dose γ-irradiation revealed changes in genes involved in cell adhesion, angiogenesis, and the immune system. Notably, peroxisome proliferator-activated receptor-(PPARα) was upregulated in response to fractionated-dose γ-irradiation. This upregulation was associated with an increase in the transcription of known PPARα target genes, including angiopoietin-like protein 4, dermokine and kallikrein-related peptide 12, which were differentially regulated by fractionated-dose γ-irradiation. Collectively, our data imply a mechanism linking γ-irradiation and secretome changes, and suggest that these changes could play a significant role in the coordinated cellular responses to harmful ionizing radiation, such as those associated with radiation therapy. This extension of our understanding of γ-irradiation-induced secretome changes has the potential to improve radiation therapy strategies. Control of inflammatory waves, improved wound healing, and stabilization of the skin barrier are imperative for minimizing such injuries. Therefore, PPARα agonists and antagonists have the potential to become important therapeutic agents for the treatment of γ-irradiation induced skin damage. Specifically, our analysis suggests that the undesirable consequences of long-term exposure to ionizing radiation could be alleviated by PPARα agonists

  17. A secretome analysis reveals that PPARα is upregulated by fractionated-dose γ-irradiation in three-dimensional keratinocyte cultures

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jee Yong; Kim, Hyun Ji; Yi, Jae Youn [Korea Institute of Radiation and Medical Sciences, Daejeon (Korea, Republic of)

    2016-05-15

    A three-dimensional (3D) environment composed of properly interconnected and differentiated cells that allows communication and cooperation among cells via secreted molecules would be expected to more accurately reflect cellular responses. Here, we investigated γ-irradiation-induced changes in the secretome of 3D-cultured keratinocytes. An analysis of keratinocyte secretome profiles following fractionated-dose γ-irradiation revealed changes in genes involved in cell adhesion, angiogenesis, and the immune system. Notably, peroxisome proliferator-activated receptor-(PPARα) was upregulated in response to fractionated-dose γ-irradiation. This upregulation was associated with an increase in the transcription of known PPARα target genes, including angiopoietin-like protein 4, dermokine and kallikrein-related peptide 12, which were differentially regulated by fractionated-dose γ-irradiation. Collectively, our data imply a mechanism linking γ-irradiation and secretome changes, and suggest that these changes could play a significant role in the coordinated cellular responses to harmful ionizing radiation, such as those associated with radiation therapy. This extension of our understanding of γ-irradiation-induced secretome changes has the potential to improve radiation therapy strategies. Control of inflammatory waves, improved wound healing, and stabilization of the skin barrier are imperative for minimizing such injuries. Therefore, PPARα agonists and antagonists have the potential to become important therapeutic agents for the treatment of γ-irradiation induced skin damage. Specifically, our analysis suggests that the undesirable consequences of long-term exposure to ionizing radiation could be alleviated by PPARα agonists.

  18. SU-E-T-429: Feasibility Study On Three-Dimensional GRID Therapy in Conventional Linacs

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Y; Meyer, J; Timmerman, R; Hrycushko, B; Chen, B; Saha, D; Jiang, S [UT Southwestern Medical Center, Dallas, TX (United States)

    2015-06-15

    Purpose: Two-dimensional GRID therapy, traditionally planned and delivered using a dedicated GRID block or MLC modulation, has shown clinical efficacy in treating bulky tumors. However, the large dose to normal tissues outside target can be limiting. We hypothesize that modulation in the third dimension will improve dose sparing of normal tissues, maximize the bystander effect within the target, and ultimately improve the therapy effectiveness. This study aims to investigate the feasibility of a three-dimensional GRID technique using conventional LINACs to achieve a 3D lattice of high dose volumes within a target. Methods: Datasets of patient’s having large tumor sizes were used to investigate the planning and delivering of 3D GRID using a Varian TrueBeam linac. Original patient contours of PTV are exported from a TPS to DICOManTX where 3D GRID targets are generated in programmable configurations. A structure of avoidance (SOA), i.e., PTV minus GRID targets, is also generated to facilitate inverse planning to achieve the desired pattern. The artificial structures were sent back to the TPS where an IMRT or VMAT plan is designed to deliver a desired high dose to GRID targets while minimizing the dose to the SOA as much as possible. Results: The programmable GRID target generator enables us to modify the target geometry to maximize the peak-to-valley ratio. Preliminary results show that plans based on spherical GRID targets achieve a higher peak-to-valley dose ratio compared with cylindrical targets. High dose spillage outside the target was eliminated. IMRT planning requires the number of beams to be larger than 16, while for VMAT the number of arcs should be at least 4 in order to achieve dosimetric goals. Conclusion: Planning and delivering 3D GRID therapy using conventional LINACs was shown to be feasible. More research and development are required before this new modality can be implemented clinically.

  19. Fabrication of malleable three-dimensional-printed customized bolus using three-dimensional scanner.

    Directory of Open Access Journals (Sweden)

    Jae Won Park

    Full Text Available A three-dimensional (3D-printed customized bolus (3D bolus can be used for radiotherapy application to irregular surfaces. However, bolus fabrication based on computed tomography (CT scans is complicated and also delivers unwanted irradiation. Consequently, we fabricated a bolus using a 3D scanner and evaluated its efficacy. The head of an Alderson Rando phantom was scanned with a 3D scanner. The 3D surface data were exported and reconstructed with Geomagic Design X software. A 3D bolus of 5-mm thickness designed to fit onto the nose was printed with the use of rubber-like printing material, and a radiotherapy plan was developed. We successfully fabricated the customized 3D bolus, and further, a CT simulation indicated an acceptable fit of the 3D bolus to the nose. There was no air gap between the bolus and the phantom surface. The percent depth dose (PDD curve of the phantom with the 3D bolus showed an enhanced surface dose when compared with that of the phantom without the bolus. The PDD of the 3D bolus was comparable with that of a commercial superflab bolus. The radiotherapy plan considering the 3D bolus showed improved target coverage when compared with that without the bolus. Thus, we successfully fabricated a customized 3D bolus for an irregular surface using a 3D scanner instead of a CT scanner.

  20. A practical three-dimensional dosimetry system for radiation therapy

    International Nuclear Information System (INIS)

    Guo Pengyi; Adamovics, John; Oldham, Mark

    2006-01-01

    There is a pressing need for a practical three-dimensional (3D) dosimetry system, convenient for clinical use, and with the accuracy and resolution to enable comprehensive verification of the complex dose distributions typical of modern radiation therapy. Here we introduce a dosimetry system that can achieve this challenge, consisting of a radiochromic dosimeter (PRESAGE trade mark sign ) and a commercial optical computed tomography (CT) scanning system (OCTOPUS trade mark sign ). PRESAGE trade mark sign is a transparent material with compelling properties for dosimetry, including insensitivity of the dose response to atmospheric exposure, a solid texture negating the need for an external container (reducing edge effects), and amenability to accurate optical CT scanning due to radiochromic optical contrast as opposed to light-scattering contrast. An evaluation of the performance and viability of the PRESAGE trade mark sign /OCTOPUS, combination for routine clinical 3D dosimetry is presented. The performance of the two components (scanner and dosimeter) was investigated separately prior to full system test. The optical CT scanner has a spatial resolution of ≤1 mm, geometric accuracy within 1 mm, and high reconstruction linearity (with a R 2 value of 0.9979 and a standard error of estimation of ∼1%) relative to independent measurement. The overall performance of the PRESAGE trade mark sign /OCTOPUS system was evaluated with respect to a simple known 3D dose distribution, by comparison with GAFCHROMIC[reg] EBT film and the calculated dose from a commissioned planning system. The 'measured' dose distribution in a cylindrical PRESAGE trade mark sign dosimeter (16 cm diameter and 11 cm height) was determined by optical-CT, using a filtered backprojection reconstruction algorithm. A three-way Gamma map comparison (4% dose difference and 4 mm distance to agreement), between the PRESAGE trade mark sign , EBT and calculated dose distributions, showed full agreement in

  1. Optimal 3-D conformal treatment planning of posterior lateral supratentorial tumors

    International Nuclear Information System (INIS)

    Gius, David; Klein, Eric; Oehmke, Fred

    1995-01-01

    Purpose/Objective: The ability to treat the brain to greater doses is limited by normal brain tissue tolerance. With the use of 3-dimensional treatment planning dose escalation will result in increased target dose while sparing normal tissue. Treatment of the supratentorial region of the brain presents several unique difficulties due to the changing contour of the calvarium, which are especially noticeable with treatment to the posterior lateral quadrant. The use of a single wedge beam is sub-optimal and a more appropriate solution would employ a two tier wedge arrangement to better conform the isodoses around the target volume. In the past it has only been possible to use a single wedge during treatment with a single port, however, the dynamic wedge presents the opportunity to employ a two tier wedge system by simultaneously using conventional and dynamic wedging. Methods and Materials: An anthropomorphic phantom with a lesion located in the posterior lateral aspect of the brain where the external surface slopes at a maximum was configured. CT generated contours outlined the external surface, normal anatomy, gross tumor, and target volumes. We used the beam's-eye-view projection from the 3D planning system to derive the conformal beams. A standard opposed lateral and posterior oblique wedge pair beam arrangements, were compared to a three field technique (PA, lateral, and vertex) which used both a single wedge arrangement and a two-tier wedge plan. Treatment plans were evaluated by calculating isodose distribution, DVH, TCP, and NTCP. Each beam arrangement was used to treat our phantom with film placed in between the phantom layers at the tumor levels to confirm the accuracy of the 3-D system calculations. Results: The three field, two-tier wedge technique isodose distribution was significantly superior when compared to the standard 2-D plans, and a moderate improvement over the three field, single wedge technique in terms of conforming dose to the tumor and

  2. Three-dimensional friction measurement during hip simulation.

    Directory of Open Access Journals (Sweden)

    Robert Sonntag

    Full Text Available Wear of total hip replacements has been the focus of many studies. However, frictional effects, such as high loading on intramodular connections or the interface to the bone, as well as friction associated squeaking have recently increased interest about the amount of friction that is generated during daily activities. The aim of this study was thus to establish and validate a three-dimensional friction setup under standardized conditions.A standard hip simulator was modified to allow for high precision measurements of small frictional effects in the hip during three-dimensional hip articulation. The setup was verified by an ideal hydrostatic bearing and validated with a static-load physical pendulum and an extension-flexion rotation with a dynamic load profile. Additionally, a pendulum model was proposed for screening measurement of frictional effects based on the damping behavior of the angular oscillation without the need for any force/moment transducer. Finally, three-dimensional friction measurements have been realized for ceramic-on-polyethylene bearings of three different sizes (28, 36 and 40 mm.A precision of less than 0.2 Nm during three-dimensional friction measurements was reported, while increased frictional torque (resultant as well as taper torque was measured for larger head diameters. These effects have been confirmed by simple pendulum tests and the theoretical model. A comparison with current literature about friction measurements is presented.This investigation of friction is able to provide more information about a field that has been dominated by the reduction of wear. It should be considered in future pre-clinical testing protocols given by international organizations of standardization.

  3. Conformation radiotherapy with eccentric multi-leaves, (1)

    International Nuclear Information System (INIS)

    Obata, Yasunori; Sakuma, Sadayuki.

    1986-01-01

    In order to extend the application of the conformation radiotherapy, the eccentric multi-leaves are equipped with the linear accelerator. The information of the position of the collimators and the dose distribution of the eccentric conformation radiotherapy are calculated by the improved algorism of the treatment planning system. In simple cases, the dose distributions for the distant region from the rotational center are measured and compared with the calculated values. Both distributions are well coincided with the error of about 5 % in the high dose region and 10 % in the low dose region. In eccentric conformation radiotherapy, it is difficult to deliver the planned dose to the lesion. The dose increases with the distance of the target area from the rotational center. And the measured value and the calculated value are well coincided with 1 % error. So after getting the dose ratio of the rotational center to the target area, the calculated dose can be delivered to the rotational center. The advantages of the eccentric conformation radiotherapy are a good coincidence of target area and treated area, a partial shielding and a hollow out technique without absorber. The limitation of the movement of the collimator from center is 5 cm at 1 m SCD. (author)

  4. Three dimensional imaging in cardiac nuclear medicine

    International Nuclear Information System (INIS)

    Torizuka, Kanji; Ishii, Yasushi; Yonekura, Yoshiharu; Yamamoto, Kazutaka; Tamaki, Takeyoshi

    1981-01-01

    Methods to obtain three dimensional images of the heart were reviewed. Gated three dimensional display reconstructed from images using bidirectional collimator, was a useful method to detect akinesis of the heart wall. Tomographic observation of the heart can be carried out by a pinhole collimator to image ischemia with high sensitivity. However the focusing plane must be carefully selected to prevent false positives. In the case of emission CT (ECT), utilization of positron emitters gave a quantitative image without correction, whereas single photon ECT needed the correction due to the absorption of γ-ray. Though the reliability of the images by ECT was high, the time required for data acquisition was much longer than that by a 7 pinhole or bidirectional collimator. (Nakanishi, T.)

  5. High-resolution liquid patterns via three-dimensional droplet shape control.

    Science.gov (United States)

    Raj, Rishi; Adera, Solomon; Enright, Ryan; Wang, Evelyn N

    2014-09-25

    Understanding liquid dynamics on surfaces can provide insight into nature's design and enable fine manipulation capability in biological, manufacturing, microfluidic and thermal management applications. Of particular interest is the ability to control the shape of the droplet contact area on the surface, which is typically circular on a smooth homogeneous surface. Here, we show the ability to tailor various droplet contact area shapes ranging from squares, rectangles, hexagons, octagons, to dodecagons via the design of the structure or chemical heterogeneity on the surface. We simultaneously obtain the necessary physical insights to develop a universal model for the three-dimensional droplet shape by characterizing the droplet side and top profiles. Furthermore, arrays of droplets with controlled shapes and high spatial resolution can be achieved using this approach. This liquid-based patterning strategy promises low-cost fabrication of integrated circuits, conductive patterns and bio-microarrays for high-density information storage and miniaturized biochips and biosensors, among others.

  6. Graphene quantum dots-three-dimensional graphene composites for high-performance supercapacitors.

    Science.gov (United States)

    Chen, Qing; Hu, Yue; Hu, Chuangang; Cheng, Huhu; Zhang, Zhipan; Shao, Huibo; Qu, Liangti

    2014-09-28

    Graphene quantum dots (GQDs) have been successfully deposited onto the three-dimensional graphene (3DG) by a benign electrochemical method and the ordered 3DG structure remains intact after the uniform deposition of GQDs. In addition, the capacitive properties of the as-formed GQD-3DG composites are evaluated in symmetrical supercapacitors. It is found that the supercapacitor fabricated from the GQD-3DG composite is highly stable and exhibits a high specific capacitance of 268 F g(-1), representing a more than 90% improvement over that of the supercapacitor made from pure 3DG electrodes (136 F g(-1)). Owing to the convenience of the current method, it can be further used in other well-defined electrode materials, such as carbon nanotubes, carbon aerogels and conjugated polymers to improve the performance of the supercapacitors.

  7. Poster - 21: Verification of Monitor Unit Calculations for Breast Field-In-Field Three-Dimensional Conformal Radiotherapy Plans

    International Nuclear Information System (INIS)

    Kosztyla, Robert; Pierce, Greg; Ploquin, Nicolas; Roumeliotis, Michael; Schinkel, Colleen

    2016-01-01

    Purpose: To determine the source of systematic monitor unit (MU) calculation discrepancies between RadCalc and Eclipse treatment planning software for three-dimensional conformal radiotherapy field-in-field breast treatments. Methods: Data were reviewed for 28 patients treated with a field-in-field breast technique with MU calculations from RadCalc that were larger than MU calculations from Eclipse for at least one field. The distance of the calculation point from the jaws was measured in each field’s beam’s-eye-view and compared with the percentage difference in MU (%ΔMU) between RadCalc and Eclipse. 10×10, 17×13 and 20×20 cm 2 beam profiles were measured using the Profiler 2 diode array for 6-MV photon beams and compared with profiles calculated with Eclipse and RadCalc using a gamma analysis (3%, 3 mm). Results: The mean %ΔMU was 1.3%±0.3%. There was a statistically-significant correlation between %ΔMU and the distance of the calculation point from the Y jaw (r=−0.43, p<0.001). RadCalc profiles differed from measured profiles, especially near the jaws. The gamma pass rate for 6-MV fields of 17×13 cm 2 field size was 95%±1% for Eclipse-generated profiles and 53%±20% for RadCalc-generated profiles (p=0.01). Conclusions: Calculations using RadCalc for field-in-field breast plans resulted in MUs that were larger than expected from previous clinical experience with wedged plans with calculation points far from the jaws due to the position of the calculation point near the jaws in the beam’s-eye-view of each field.

  8. Poster - 21: Verification of Monitor Unit Calculations for Breast Field-In-Field Three-Dimensional Conformal Radiotherapy Plans

    Energy Technology Data Exchange (ETDEWEB)

    Kosztyla, Robert; Pierce, Greg; Ploquin, Nicolas; Roumeliotis, Michael; Schinkel, Colleen [Tom Baker Cancer Centre, Calgary, AB, Tom Baker Cancer Centre, Tom Baker Cancer Centre, Tom Baker Cancer Centre, Calgary, AB, Tom Baker Cancer Centre, Calgary, AB (Canada)

    2016-08-15

    Purpose: To determine the source of systematic monitor unit (MU) calculation discrepancies between RadCalc and Eclipse treatment planning software for three-dimensional conformal radiotherapy field-in-field breast treatments. Methods: Data were reviewed for 28 patients treated with a field-in-field breast technique with MU calculations from RadCalc that were larger than MU calculations from Eclipse for at least one field. The distance of the calculation point from the jaws was measured in each field’s beam’s-eye-view and compared with the percentage difference in MU (%ΔMU) between RadCalc and Eclipse. 10×10, 17×13 and 20×20 cm{sup 2} beam profiles were measured using the Profiler 2 diode array for 6-MV photon beams and compared with profiles calculated with Eclipse and RadCalc using a gamma analysis (3%, 3 mm). Results: The mean %ΔMU was 1.3%±0.3%. There was a statistically-significant correlation between %ΔMU and the distance of the calculation point from the Y jaw (r=−0.43, p<0.001). RadCalc profiles differed from measured profiles, especially near the jaws. The gamma pass rate for 6-MV fields of 17×13 cm{sup 2} field size was 95%±1% for Eclipse-generated profiles and 53%±20% for RadCalc-generated profiles (p=0.01). Conclusions: Calculations using RadCalc for field-in-field breast plans resulted in MUs that were larger than expected from previous clinical experience with wedged plans with calculation points far from the jaws due to the position of the calculation point near the jaws in the beam’s-eye-view of each field.

  9. Thermal Investigation of Three-Dimensional GaN-on-SiC High Electron Mobility Transistors

    Science.gov (United States)

    2017-07-01

    University of L’Aquila, (2011). 23 Rao, H. & Bosman, G. Hot-electron induced defect generation in AlGaN/GaN high electron mobility transistors. Solid...AFRL-RY-WP-TR-2017-0143 THERMAL INVESTIGATION OF THREE- DIMENSIONAL GaN-on-SiC HIGH ELECTRON MOBILITY TRANSISTORS Qing Hao The University of Arizona...clarification memorandum dated 16 Jan 09. This report is available to the general public, including foreign nationals. Copies may be obtained from the

  10. Assessment of dose homogeneity in conformal interstitial breast brachytherapy with special respect to ICRU recommendations

    Directory of Open Access Journals (Sweden)

    Tibor Major

    2011-09-01

    Full Text Available Purpose: To present the results of dose homogeneity analysis for breast cancer patients treated with image-basedconformal interstitial brachytherapy, and to investigate the usefulness of the ICRU recommendations. Material and methods: Treatment plans of forty-nine patients who underwent partial breast irradiation with interstitialbrachytherapy were analyzed. Quantitative parameters were used to characterize dose homogeneity. Dose nonuniformityratio (DNR, dose homogeneity index (DHI, uniformity index (UI and quality index (QI were calculated.Furthermore, parameters recommended by the ICRU 58 such as minimum target dose (MTD, mean central dose (MCD,high dose volume, low dose volume and the spread between local minimum doses were determined. Correlationsbetween the calculated homogeneity parameters and usefulness of the ICRU parameters in image-based brachytherapywere investigated. Results: Catheters with mean number of 15 (range: 6-25 were implanted in median 4 (range: 3-6 planes. The volu -me of the PTV ranged from 15.5 cm3 to 176 cm3. The mean DNR was 0.32, the DHI 0.66, the UI 1.49 and the QI 1.94. Relatedto the prescribed dose, the MTD was 69% and the MCD 135%. The mean high dose volume was 8.1 cm3 (10%, whilethe low dose volume was 63.8 cm3 (96%. The spread between minimum doses in central plane ranged from –14% to+20%. Good correlation was found between the DNR and the DHI (R2 = 0.7874, and the DNR correlated well with theUI (R2 = 0.7615 also. No correlation was found between the ICRU parameters and any other volumetric parameters. Conclusions: To characterize the dose uniformity in high-dose rate breast implants, DVH-related homogeneityparameters representing the full 3D dose distributions are mandatory to be used. In many respects the current re commendationsof the ICRU Report 58 are already outdated, and it is well-timed to set up new recommendations, whichare more feasible for image-guided conformal interstitial brachytherapy.

  11. SU-E-T-752: Three-Dimensional Carcinogenic Maps Induced by Photons and Protons

    Energy Technology Data Exchange (ETDEWEB)

    Manem, V; Paganetti, H [Massachusetts General Hospital, Boston, MA (United States)

    2015-06-15

    Purpose: Evaluate the excess relative risk (ERR) induced by photons and protons in each voxel of the lung, and display it as a three-dimensional map, known as the ERRM (i.e. excess relative risk map) along with the dose distribution map. In addition, we also study the effect of variations in the linear energy transfer (LET) distribution on ERRM for a given proton plan. Methods: The excess relative risk due to radiation is estimated using the initiation-inactivation-proliferation formalism. This framework accounts for three biological phenomenon: mutation induction, cell kill and proliferation. Cell kill and mutation induction are taken as a function of LET using experimental data. LET distributions are calculated using a Monte Carlo algorithm. ERR is then estimated for each voxel in the organ, and displayed as a three dimensional carcinogenic map. Results: The differences in the ERR’s between photons and protons is seen from the three-dimensional ERR map. In addition, we also varied the LET of a proton plan and observed the differences in the corresponding ERR maps demonstrating variations in the ERR maps depend on features of a proton plan. Additionally, our results suggest that any two proton plans that have the same integral dose does not necessarily imply identical ERR maps, and these changes are due to the variations in the LET distribution map. Conclusion: Clinically, it is important to have a three dimensional display of biological end points. This study is an effort to introduce 3D ERR maps into the treatment planning workflow for certain sites such as pediatric head and neck tumors.

  12. Non small cells stage I bronchial cancers: three-dimensional radiotherapy and radiotherapy in stereotactic conditions; Cancers bronchiques non a petites cellules de stade I: radiotherapie tridimensionnelle et radiotherapie en conditions stereotaxiques

    Energy Technology Data Exchange (ETDEWEB)

    Schipman, B.; Bosset, J.F. [CHU, 25 - Besancon (France); Marchesi, V.; Beckendorf, V.; Desandes, E.; Peiffert, D. [CRLCC Alexis-Vautrin, 54 - Vandaeuvre-les-Nancy (France); Bosset, M. [CHU, 26 - Valence (France)

    2010-10-15

    The authors report a comparison between three-dimensional conformation radiotherapy and robotic irradiation in stereotactic conditions (with CyberKnife) for patients suffering from a bronchial cancer with no small cells of stage I. Acute and late toxicity have been recorded, and the monitoring comprised a clinic examination and a thoracic scanography. The external radiotherapy results in an important local control rate and an acceptable toxicity. Some prospective studies are still needed to compare three-dimensional conformation respiratory-gated radiotherapy and radiotherapy in stereotactic conditions. Short communication

  13. COSMO-PAFOG: Three-dimensional fog forecasting with the high-resolution COSMO-model

    Science.gov (United States)

    Hacker, Maike; Bott, Andreas

    2017-04-01

    The presence of fog can have critical impact on shipping, aviation and road traffic increasing the risk of serious accidents. Besides these negative impacts of fog, in arid regions fog is explored as a supplementary source of water for human settlements. Thus the improvement of fog forecasts holds immense operational value. The aim of this study is the development of an efficient three-dimensional numerical fog forecast model based on a mesoscale weather prediction model for the application in the Namib region. The microphysical parametrization of the one-dimensional fog forecast model PAFOG (PArameterized FOG) is implemented in the three-dimensional nonhydrostatic mesoscale weather prediction model COSMO (COnsortium for Small-scale MOdeling) developed and maintained by the German Meteorological Service. Cloud water droplets are introduced in COSMO as prognostic variables, thus allowing a detailed description of droplet sedimentation. Furthermore, a visibility parametrization depending on the liquid water content and the droplet number concentration is implemented. The resulting fog forecast model COSMO-PAFOG is run with kilometer-scale horizontal resolution. In vertical direction, we use logarithmically equidistant layers with 45 of 80 layers in total located below 2000 m. Model results are compared to satellite observations and synoptic observations of the German Meteorological Service for a domain in the west of Germany, before the model is adapted to the geographical and climatological conditions in the Namib desert. COSMO-PAFOG is able to represent the horizontal structure of fog patches reasonably well. Especially small fog patches typical of radiation fog can be simulated in agreement with observations. Ground observations of temperature are also reproduced. Simulations without the PAFOG microphysics yield unrealistically high liquid water contents. This in turn reduces the radiative cooling of the ground, thus inhibiting nocturnal temperature decrease. The

  14. Induction chemotherapy with carboplatin, irinotecan, and paclitaxel followed by high dose three-dimension conformal thoracic radiotherapy (74 Gy) with concurrent carboplatin, paclitaxel, and gefitinib in unresectable stage IIIA and stage IIIB non-small cell lung cancer.

    Science.gov (United States)

    Stinchcombe, Thomas E; Morris, David E; Lee, Carrie B; Moore, Dominic T; Hayes, D Neil; Halle, Jan S; Rivera, M Patricia; Rosenman, Julian G; Socinski, Mark A

    2008-03-01

    Combined modality therapy is a standard therapy for patients with unresectable stage III non-small cell lung cancer (NSCLC). Gefitinib is active in advanced NSCLC, and in preclinical models, it potentiates the activity of radiation therapy. We investigate the tolerability of gefitinib in combined modality therapy in combination with three-dimensional thoracic conformal radiation therapy (3-dimensional TCRT). Stage III patients with a good performance status were treated with induction chemotherapy (carboplatin area under the curve [AUC] of 5, irinotecan 100 mg/m(2), and paclitaxel 175 mg/m(2) days 1 and 22) with pegfilgrastim support followed by concurrent chemotherapy (carboplatin AUC 2, and paclitaxel 45 mg/m(2) weekly) and gefitinib 250 mg daily beginning on day 43 with 3-dimensional TCRT to 74 Gy. Between March 2004 and January 2006, 23 patients received treatment on the trial: median age 62 years (range 44-82), 52% female, 61% stage IIIA, 61% performance status 0, 17% > or =5% weight loss, and 91% underwent positron emission tomography staging. Induction chemotherapy with pegfilgrastim support was well tolerated and active (partial response rate, 24%; stable disease, 76%; and early progression, 0%). Twenty-one patients initiated the concurrent chemoradiation, and 20 patients completed therapy to 74 Gy. The primary toxicities of concurrent chemoradiation were grade 3 esophagitis (19.5%) and cardiac arrhythmia (atrial fibrillation) (9.5%). The median progression-free survival and overall survival were 9 months (95% confidence intervals [CI]: 7-13 months) and 16 months (95% CI: 10-20 months), respectively. Treatment with induction chemotherapy and gefitinib concurrent with 3-dimensional TCRT has an acceptable toxicity and tolerability, but the survival results were disappointing.

  15. Cost-benefit analysis of 3D conformal radiation therapy. Treatment of prostate cancer as a model

    International Nuclear Information System (INIS)

    Cho, K.H.; Khan, F.M.; Levitt, S.H.

    1999-01-01

    Three-dimensional conformal radiation therapy (3D-CRT) is a promising new treatment technique based on the principle that improved precision in both tumor definition and dose delivery will enhance outcomes by maximizing dose to the tumor area while minimizing dose to normal tissue. Using a cost-benefit analysis, in terms of outcomes, we first examined the overall risks and benefits of 3D-CRT. We then used the treatment of prostate cancer as a model to compare actual clinical outcomes reported between 3D-CRT and standard radiation therapy (SRT). Our analysis shows that application of 3D-CRT to the clinical setting remains difficult because of the continual difficulties of target definition, and that dose escalation cannot yet be justified on the basis of the lack of benefit found, and suggested increased late toxicity, in most of the dose escalation series compared with SRT. (orig.)

  16. Uniform stable conformal convolutional perfectly matched layer for enlarged cell technique conformal finite-difference time-domain method

    International Nuclear Information System (INIS)

    Wang Yue; Wang Jian-Guo; Chen Zai-Gao

    2015-01-01

    Based on conformal construction of physical model in a three-dimensional Cartesian grid, an integral-based conformal convolutional perfectly matched layer (CPML) is given for solving the truncation problem of the open port when the enlarged cell technique conformal finite-difference time-domain (ECT-CFDTD) method is used to simulate the wave propagation inside a perfect electric conductor (PEC) waveguide. The algorithm has the same numerical stability as the ECT-CFDTD method. For the long-time propagation problems of an evanescent wave in a waveguide, several numerical simulations are performed to analyze the reflection error by sweeping the constitutive parameters of the integral-based conformal CPML. Our numerical results show that the integral-based conformal CPML can be used to efficiently truncate the open port of the waveguide. (paper)

  17. Current situation of high-dose-rate brachytherapy for cervical cancer in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Rogerio Matias Vidal da; Souza, Divanizia do Nascimento, E-mail: rmv.fisica@gmail.com [Universidade Federal de Sergipe (UFS), Sao Cristovao, SE (Brazil); Pinezi, Juliana Castro Dourado [Pontificia Universidade Catolica de Goias (PUC-Goias), Goiania, GO (Brazil); Macedo, Luiz Eduardo Andrade [Hospital Chama, Arapiraca, AL (Brazil)

    2014-05-15

    To assess the current situation of high-dose-rate (HDR) brachytherapy for cancer of the cervix in Brazil, regarding apparatuses, planning methods, prescription, fractionation schedule and evaluation of dose in organs at risk. Materials and methods: in the period between March/2012 and May/2013, a multiple choice questionnaire was developed and sent to 89 Brazilian hospitals which perform HDR brachytherapy. Results: sixty-one services answered the questionnaire. All regions of the country experienced a sharp increase in the number of HDR brachytherapy services in the period from 2001 to 2013. As regards planning, although a three-dimensional planning software was available in 91% of the centers, conventional radiography was mentioned by 92% of the respondents as their routine imaging method for such a purpose. Approximately 35% of respondents said that brachytherapy sessions are performed after teletherapy. The scheme of four 7 Gy intracavitary insertions was mentioned as the most frequently practiced. Conclusion: the authors observed that professionals have difficulty accessing adjuvant three-dimensional planning tools such as computed tomography and magnetic resonance imaging. (author)

  18. Three-dimensional CT imaging of soft-tissue anatomy

    International Nuclear Information System (INIS)

    Fishman, E.K.; Ney, D.R.; Magid, D.; Kuhlman, J.E.

    1988-01-01

    Three-dimensional display of computed tomographic data has been limited to skeletal structures. This was in part related to the reconstruction algorithm used, which relied on a binary classification scheme. A new algorithm, volumetric rendering with percentage classification, provides the ability to display three-dimensional images of muscle and soft tissue. A review was conducted of images in 35 cases in which muscle and/or soft tissue were part of the clinical problem. In all cases, individual muscle groups could be clearly identified and discriminated. Branching vessels in the range of 2.3 mm could be identified. Similarly, lymph nodes could be clearly defined. High-resolution three-dimensional images were found to be useful both in providing an increased understanding of complex muscle and soft tissue anatomy and in surgical planning

  19. The influence of high doses of radiation in citrine stones

    International Nuclear Information System (INIS)

    Teixeira, M. I.; Caldas, L. V. E.

    2014-08-01

    The possibility of using samples of Brazilian stones as quartz, amethyst, topaz, jasper, etc. for high-dose dosimetry has been studied in recent years at IPEN, using the techniques of optical absorption (Oa), thermoluminescent (Tl), optically stimulated luminescence (OSL) and resonance paramagnetic electron (EPR). In this work, the Tl properties of citrine samples were studied. They were exposed to different doses of gamma radiation ( 60 Co). The natural citrine stone was extracted from a mine in Minas Gerais state, Brazil; it is a tecto silicate ranked as one of three-dimensional structure, showing clear yellow to golden brown color. The natural citrine stone is classified as quartz (SiO 2 ), and it has a lower symmetry and more compact reticulum. The Tl emission curve showed two peaks at 160 grades C and 220 grades C. To remove the Tl peak (160 grades C) of the sintered citrine pellet glow curves, different thermal treatments were tested during several time intervals. The Tl dose-response curve between 50 Gy and 100 kGy, the reproducibility of Tl response and the lower detection dose were obtained. The results show that citrine may be useful as high-dose detectors. (Author)

  20. The influence of high doses of radiation in citrine stones

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M. I. [Universidade Nove de Julho - UNINOVE, Rua Vergueiro 235/249, 01504-001 Sao Paulo (Brazil); Caldas, L. V. E., E-mail: miteixeira@ipen.br [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

    2014-08-15

    The possibility of using samples of Brazilian stones as quartz, amethyst, topaz, jasper, etc. for high-dose dosimetry has been studied in recent years at IPEN, using the techniques of optical absorption (Oa), thermoluminescent (Tl), optically stimulated luminescence (OSL) and resonance paramagnetic electron (EPR). In this work, the Tl properties of citrine samples were studied. They were exposed to different doses of gamma radiation ({sup 60}Co). The natural citrine stone was extracted from a mine in Minas Gerais state, Brazil; it is a tecto silicate ranked as one of three-dimensional structure, showing clear yellow to golden brown color. The natural citrine stone is classified as quartz (SiO{sub 2}), and it has a lower symmetry and more compact reticulum. The Tl emission curve showed two peaks at 160 grades C and 220 grades C. To remove the Tl peak (160 grades C) of the sintered citrine pellet glow curves, different thermal treatments were tested during several time intervals. The Tl dose-response curve between 50 Gy and 100 kGy, the reproducibility of Tl response and the lower detection dose were obtained. The results show that citrine may be useful as high-dose detectors. (Author)