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  1. High-dose radiotherapy (60 Gy) with oral UFT/folinic acid and escalating doses of oxaliplatin in patients with non-resectable locally advanced rectal cancer (LARC)

    DEFF Research Database (Denmark)

    Weber Vestermark, Lene; Jensen, Helle A; Pfeiffer, Per

    2012-01-01

    Consensus is that patients with locally advanced rectal cancer (LARC) should receive long-term chemoradiotherapy (CRT) before surgery. With the intent to offer the patients intensified concomitant chemotherapy (CT) to improve outcome and to assess tolerability and toxicity of oxaliplatin (Ox) a p...

  2. SU-E-T-126: Dosimetric Comparisons of VMAT, IMRT and 3DCRT for Locally Advanced Rectal Cancer with Simultaneous Integrated Boost

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    Zhao, J; Wang, J; Zhang, Z; Hu, W [Fudan University Shanghai Caner Center, Shanghai, Shanghai (China)

    2014-06-01

    Purpose: The purpose of this study is to compare the dosimetric differences among volumetric modulated arc therapy (VMAT), fixed-field intensity modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3D-CRT) for the preoperative locally advanced rectal cancer (LARC). Methods: Ten LARC patients treated in our department using the simultaneous escalate strategy were retrospectively analyzed in this study. All patients had T3 with N+/− and were treated with IMRT. Two additional VMAT and 3DCRT plans were created for each patient. Both IMRT and VMAT had similar optimization objectives. The prescription was 50Gy to the PTV and 55Gy to the GTV. The target coverage and organs at risk were compared for all the techniques.The paired, two-tailed Wilcoxcon signed-rank test was applied for statistical analysis. Results: IMRT and VMAT plans achieved comparable tumor response except for the conformality index (1.07 vs 1.19 and 1.08 vs 1.03 of IMRT vs VMAT for PTV-G and PTV-C respectively). Compared to VMAT, IMRT showed superior or similar dose sparing in the small bowel, bladder, femoral head. Both IMRT and VMAT had better organs at risk sparing and homogeneity index of PTV-G. Conclusion: All 3DCRT, IMRT and VMAT meet the prescript. The IMRT and VMAT provided comparable dosemitric parameters for target volume. IMRT shows better sparing for small bowel, bladder, femoral heads and normal tissue to 3DCRT and VMAT.

  3. Analysis of superficial fluorescence patterns in nonmelanoma skin cancer during photodynamic therapy by a dosimetric model

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    Salas-García, I.; Fanjul-Vélez, F.; Arce-Diego, J. L.

    2016-03-01

    In this work the superficial fluorescence patterns in different nonmelanoma skin cancers and their photodynamic treatment response are analysed by a fluorescence based dosimetric model. Results show differences of even more than 50% in the fluorescence patterns as photodynamic therapy progresses depending on the malignant tissue type. They demonstrate the great relevance of the biological media as an additional dosimetric factor and contribute to the development of a future customized therapy with the assistance of dosimetric tools to interpret the fluorescence images obtained during the treatment monitoring and the differential photodiagnosis.

  4. Dosimetric predictors of diarrhea during radiotherapy for prostate cancer

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    Sanguineti, Giuseppe [Radiation Oncology, Univ. of Texas Medical Branch, Galveston, TX (United States); Endres, Eugene J.; Parker, Brent C. [Physics Dept., Univ. of Texas Medical Branch, Galveston, TX (United States); Sormani, Maria Pia [Biostatistics Unit, Univ. of Genoa (Italy)

    2009-06-15

    Purpose: to investigate dosimetric predictors of diarrhea during radiotherapy (RT) for prostate cancer. Patients and methods: all patients who underwent external-beam radiotherapy as part of treatment for localized prostate cancer at the University of Texas Medical Branch, Galveston, TX, USA, from May 2002 to November 2006 were extracted from the own database. From the cumulative dose-volume histogram (DVH), the absolute volumes (V-value) of intestinal cavity (IC) receiving 15, 30, and 45 Gy were extracted for each patient. Acute gastrointestinal toxicity was prospectively scored at each weekly treatment visit according to CTC (common toxicity criteria) v2.0. The endpoint was the development of peak grade {>=} 2 diarrhea during RT. Various patient, tumor, and treatment characteristics were evaluated using logistic regression. Results: 149 patients were included in the analysis, 112 (75.2%) treated with whole-pelvis intensity-modulated radiotherapy (WP-IMRT) and 37 (24.8%) with prostate-only RT, including or not including, the seminal vesicles (PORT {+-} SV). 45 patients (30.2%) developed peak grade {>=} 2 diarrhea during treatment. At univariate analysis, IC-V{sub 15} and IC-V{sub 30}, but not IC-V{sub 45}, were correlated to the endpoint; at multivariate analysis, only IC-V{sub 15} (p = 0.047) along with peak acute proctitis (p = 0.041) was independently correlated with the endpoint. Conclusion: these data provide a novel and prostate treatment-specific ''upper limit'' DVH for IC. (orig.)

  5. Detection and localization of Mip-3alpha/LARC/Exodus, a macrophage proinflammatory chemokine, and its CCR6 receptor in human pancreatic cancer.

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    Kleeff, J; Kusama, T; Rossi, D L; Ishiwata, T; Maruyama, H; Friess, H; Büchler, M W; Zlotnik, A; Korc, M

    1999-05-17

    Macrophage Proinflammatory Human Chemokine-3alpha (Mip-3alpha/LARC/Exodus) belongs to a large family of chemotactic cytokines, which participate in directing inflammatory cell migration and in modulating angiogenesis. Mip-3alpha signals through a recently identified G-protein linked 7-transmembrane receptor, CCR6. In this study, we have characterized the expression of Mip-3alpha and CCR6 in 12 normal and 16 cancerous human pancreatic tissues and in 4 cultured pancreatic cancer cell lines, and assessed the effects of Mip-3alpha on growth and invasion of these cell lines. Pancreatic cancer tissues markedly overexpressed Mip-3alpha in comparison with normal pancreatic samples. By in situ hybridization Mip-3alpha and CCR6 mRNA moieties were present in cancer cells within the tumors. In addition, Mip-3alpha was abundant in the macrophages infiltrating the tumor mass. Mip-3alpha and its receptor CCR6 were expressed in all 4 tested pancreatic cancer cell lines. Mip-3alpha stimulated the growth of one cell line, enhanced the migration of another cell line, and was without effect in the other 2 cell lines. Together, our findings suggest that Mip-3alpha has the potential to act via autocrine and paracrine mechanisms to contribute to the pathobiology of human pancreatic cancer.

  6. Patient feature based dosimetric Pareto front prediction in esophageal cancer radiotherapy

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    Wang, Jiazhou; Zhao, Kuaike; Peng, Jiayuan; Xie, Jiang; Chen, Junchao; Zhang, Zhen; Hu, Weigang, E-mail: jackhuwg@gmail.com [Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, China and Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Jin, Xiance [The 1st Affiliated Hospital of Wenzhou Medical College, Wenzhou, Zhejiang 325000 (China); Studenski, Matthew [Department of Radiation Oncology, University of Miami-Miller School of Medicine, Miami, Florida 33136 (United States)

    2015-02-15

    Purpose: To investigate the feasibility of the dosimetric Pareto front (PF) prediction based on patient’s anatomic and dosimetric parameters for esophageal cancer patients. Methods: Eighty esophagus patients in the authors’ institution were enrolled in this study. A total of 2928 intensity-modulated radiotherapy plans were obtained and used to generate PF for each patient. On average, each patient had 36.6 plans. The anatomic and dosimetric features were extracted from these plans. The mean lung dose (MLD), mean heart dose (MHD), spinal cord max dose, and PTV homogeneity index were recorded for each plan. Principal component analysis was used to extract overlap volume histogram (OVH) features between PTV and other organs at risk. The full dataset was separated into two parts; a training dataset and a validation dataset. The prediction outcomes were the MHD and MLD. The spearman’s rank correlation coefficient was used to evaluate the correlation between the anatomical features and dosimetric features. The stepwise multiple regression method was used to fit the PF. The cross validation method was used to evaluate the model. Results: With 1000 repetitions, the mean prediction error of the MHD was 469 cGy. The most correlated factor was the first principal components of the OVH between heart and PTV and the overlap between heart and PTV in Z-axis. The mean prediction error of the MLD was 284 cGy. The most correlated factors were the first principal components of the OVH between heart and PTV and the overlap between lung and PTV in Z-axis. Conclusions: It is feasible to use patients’ anatomic and dosimetric features to generate a predicted Pareto front. Additional samples and further studies are required improve the prediction model.

  7. Clinical and dosimetric predictors of acute hematologic toxicity in rectal cancer patients undergoing chemoradiotherapy

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    Yang, T. Jonathan; Oh, Jung Hun; Apte, Aditya; Son, Christina H.; Deasy, Joseph O.; Goodman, Karyn A.

    2016-01-01

    Background and purpose To identify clinical and dosimetric factors associated with hematologic toxicity (HT) during chemoradiotherapy for rectal cancer. Materials and methods We analyzed 120 rectal cancer patients treated with neoadjuvant pelvic radiotherapy (PRT) with concurrent 5-fluorouracil-based chemotherapy. The coxal (ilium, ischium, and pubis) bone marrow (BM), sacral BM, and femoral BM were contoured and dose-volume parameters were extracted. Associations between cell count trend and clinical predictors were tested using repeated-measures analysis of variance (ANOVA) test. Associations between clinical variables, Vx (percentage volume receiving x Gy), and cell count ratio at nadir were tested using linear regression models. Results Nadirs for white blood cell count (WBC), absolute neutrophil count (ANC), and platelets (PLT) occurred in the second week of PRT and the fifth week for hemoglobin and absolute lymphocyte count (ALC). Using cell count ratio, patients treated with 3DCRT had a lower WBC ratio trend during PRT compared to patients treated with IMRT (p = 0.04), and patients ≥59 years of age had a lower hemoglobin ratio trend during PRT (p = 0.02). Using absolute cell count, patients treated with 3DCRT had lower ANC cell count trend (p = 0.03), and women had lower hemoglobin cell count trend compared to men (p = 0.03). On univariate analysis, use of 3DCRT was associated with a lower WBC ratio at nadir (p = 0.02). On multiple regression analysis using dosimetric variables, coxal BM V45 (p = 0.03) and sacral BM V45 (p = 0.03) were associated with a lower WBC and ANC ratio at nadir, respectively. Conclusions HT trends during PRT revealed distinct patterns: WBC, ANC, and PLT cell counts reach nadirs early and recover, while hemoglobin and ALC decline steadily. Patients who were treated with 3DCRT and older patients experienced lower cell count ratio trend during PRT. Dosimetric constraints using coxal BM V45 and sacral BM V45 can be considered. PMID

  8. Dosimetrically Triggered Adaptive Intensity Modulated Radiation Therapy for Cervical Cancer

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    Lim, Karen [Department of Radiation Oncology, Liverpool Hospital, Sydney (Australia); Stewart, James [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario (Canada); Kelly, Valerie [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Xie, Jason [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Brock, Kristy K. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan (United States); Moseley, Joanne [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Cho, Young-Bin; Fyles, Anthony [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Lundin, Anna; Rehbinder, Henrik; Löf, Johan [RaySearch Laboratories AB, Stockholm (Sweden); Jaffray, David A. [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Techna Institute for the Advancement of Technology for Health, Toronto, Ontario (Canada); Milosevic, Michael, E-mail: mike.milosevic@rmp.uhn.ca [Radiation Medicine Program, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada)

    2014-09-01

    Purpose: The widespread use of intensity modulated radiation therapy (IMRT) for cervical cancer has been limited by internal target and normal tissue motion. Such motion increases the risk of underdosing the target, especially as planning margins are reduced in an effort to reduce toxicity. This study explored 2 adaptive strategies to mitigate this risk and proposes a new, automated method that minimizes replanning workload. Methods and Materials: Thirty patients with cervical cancer participated in a prospective clinical study and underwent pretreatment and weekly magnetic resonance (MR) scans over a 5-week course of daily external beam radiation therapy. Target volumes and organs at risk (OARs) were contoured on each of the scans. Deformable image registration was used to model the accumulated dose (the real dose delivered to the target and OARs) for 2 adaptive replanning scenarios that assumed a very small PTV margin of only 3 mm to account for setup and internal interfractional motion: (1) a preprogrammed, anatomy-driven midtreatment replan (A-IMRT); and (2) a dosimetry-triggered replan driven by target dose accumulation over time (D-IMRT). Results: Across all 30 patients, clinically relevant target dose thresholds failed for 8 patients (27%) if 3-mm margins were used without replanning. A-IMRT failed in only 3 patients and also yielded an additional small reduction in OAR doses at the cost of 30 replans. D-IMRT assured adequate target coverage in all patients, with only 23 replans in 16 patients. Conclusions: A novel, dosimetry-triggered adaptive IMRT strategy for patients with cervical cancer can minimize the risk of target underdosing in the setting of very small margins and substantial interfractional motion while minimizing programmatic workload and cost.

  9. Dosimetric impact of Acuros XB dose calculation algorithm in prostate cancer treatment using RapidArc

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    Suresh Rana

    2013-01-01

    Full Text Available Purpose: The purpose of this study is to assess the dosimetric impact of Acuros XB dose calculation algorithm (AXB, in comparisons with Anisotropic Analytical Algorithm (AAA calculations in prostate cancer treatment using RapidArc. Materials and Methods: A computed tomography (CT dataset of low-risk prostate cancer patients treated at Arizona Center for Cancer Care was selected and contoured for prostate, seminal vesicles, and organs at risk (OARs(rectum, bladder, and femur heads. Plans were created for 6 MV photon beam using RapidArc technique in Eclipse treatment planning system. Dose calculations were performed with AAA and AXB for same number of monitor units and identical beam setup. Mean and maximum doses to planning target volume (PTV and OARs were analyzed. Additionally, minimum dose to PTV and V100 was analyzed. Finally, point-dose difference between planar dose distributions of AAA and AXB plans was investigated. Results: The highest dose difference was up to 0.43% (range: 0.05−0.43%, P> 0.05 for PTV and 1.98% (range: 0.22−1.98%, P> 0.05 for OARs with AAA predicting higher dose than AXB. The V100 values of AAA plans (95 % and AXB plans (range: 93.1−97.9 % had an average difference of 0.89±1.47% with no statistical significance (P = 0.25411. The point-dose difference analysis showed that AAA predicted higher dose than AXB at significantly higher percentage (in average 94.15 of total evaluated points. Conclusion: The dosimetric results of this study suggest that the AXB can perform the dose computation comparable to AAA in RapidArc prostate cancer treatment plans that are generated by a partial single-arc technique.

  10. Dose escalation in permanent brachytherapy for prostate cancer: dosimetric and biological considerations

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    Li, X Allen [Department of Radiation Oncology, University of Maryland, School of Medicine, 22 South Greene Street, Baltimore, MD 21201-1595 (United States); Wang, Jian Z [Department of Radiation Oncology, University of Maryland, School of Medicine, 22 South Greene Street, Baltimore, MD 21201-1595 (United States); Stewart, Robert D [School of Health Sciences, Purdue University, West Lafayette, IN 47907-1338 (United States); Di Biase, Steven J [Department of Radiation Oncology, University of Maryland, School of Medicine, 22 South Greene Street, Baltimore, MD 21201-1595 (United States)

    2003-09-07

    . For example, increasing the PB prescribed dose from 145 to 180 Gy increases EUD for the rectum by only 3%. Our studies indicate that the dose to urethra can be kept within 100-120% of the prescription dose for all the dose levels studied. In conclusion, dose escalation in permanent implant for localized prostate cancer may be advantageous. It is dosimetrically possible to increase dose to prostate without a substantial increase in the dose to the rectum and urethra. Based on the results of our studies, a prospective dose escalation trial for prostate permanent implants has been initiated at our institution.

  11. A dosimetric evaluation of VMAT for the treatment of non-small cell lung cancer.

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    Merrow, Caitlin E; Wang, Iris Z; Podgorsak, Matthew B

    2012-09-01

    The purpose of this study was to demonstrate the dosimetric potential of volumetric-modulated arc therapy (VMAT) for the treatment of patients with medically inoperable stage I/II non-small cell lung cancer (NSCLC) with stereotactic body radiation therapy (SBRT). Fourteen patients treated with 3D CRT with varying tumor locations, tumor sizes, and dose fractionation schemes were chosen for study. The prescription doses were 48 Gy in 4 fractions, 52.5 Gy in 5 fractions, 57.5 Gy in 5 fractions, and 60 Gy in 3 fractions for 2, 5, 1, and 6 patients, respectively. VMAT treatment plans with a mix of two to three full and partial noncoplanar arcs with 5°-25° separations were retrospectively generated using Eclipse version 10.0. The 3D CRT and VMAT plans were then evaluated by comparing their target dose, critical structure dose, high dose spillage, and low dose spillage as defined according to RTOG 0813 and RTOG 0236 protocols. In the most dosimetrically improved case, VMAT was able to decrease the dose from 17.35 Gy to 1.54 Gy to the heart. The D(2cm) decreased in 11 of 14 cases when using VMAT. The three that worsened were still within the acceptance criteria. Of the 14 3D CRT plans, seven had a D(2cm) minor deviation, while only one of the 14 VMAT plans had a D(2cm) minor deviation. The R(50%) improved in 13 of the 14 VMAT cases. The one case that worsened was still within the acceptance criteria of the RTOG protocol. Of the 14 3D CRT plans, seven had an R(50%) deviation. Only one of the 14 VMAT plans had an R(50%) deviation, but it was still improved compared to the 3D CRT plan. In this cohort of patients, no evident dosimetric compromises resulted from planning SBRT treatments with VMAT relative to the 3D CRT treatment plans actually used in their treatment.

  12. Dosimetric comparison of 3DCRT versus IMRT in whole breast irradiation of early stage breast cancer

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    Mudasir Ashraf

    2014-08-01

    Full Text Available Purpose: The counseling regarding the treatment option is an important objective in the management of early stages breast cancer. In this study, we attempt to compare and analyze the dosimetric aspects of 3DRT over IMRT in the whole breast radiotherapy.Methods and Materials:  Both right and left sided computed tomography simulations of 14 women with early stage breast cancer were used for our retrospective study to compare the 3DCRT and IMRT. The dose prescribed was 50 Gy in 25 fractions to the whole breast PTV. The PTV was defined by adding unequal margins to the directional safety margin status of each lumpectomy cavity (i.e., medial, lateral, superior, inferior and deep margins measured from the tumor front after the examination of the surgical specimen: 2, 1.5, and 1 cm for resection margins < 1 cm, 1-2 cm, and > 2cm, respectively. And than modified so that it was no longer closer than 3mm to the skin surface and was no deep than the lung –chest interface. The prescribed dose delivered in 5 fractions per week schedule. Treatment plans were compared for target minimum dose, maximum dose, mean dose, conformity index, heterogeneity index and doses to organs at risk were compared and analysed.Results: The target coverage was achieved with 90% prescription to the 95% of the PTV. Conformity to the PTV was significantly higher with 3DCRT technique than IMRT. 3DCRT technique seems better in sparing critical organs parameters like lung V20 and Mean, heart, V25, Maximum, both lungs V20, Mean and Dose to the Normal Healthy tissue.Conclusion: We conclude from our study that treatment technique selection for whole Breast irradiation is an important factor in sparing the adjacent normal structures and in determining the associated risk. 3DCRT produces better conformity and heterogeneity indices of the target volume, also reduces dose to OARs the 3DCRT reduces the risk of radiation induced heart diseases

  13. Determination of dosimetric parameters for shielded 153Gd source in prostate cancer brachytherapy

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    Ghorbani, Mahdi; Ghatei, Najmeh; Mehrpouyan, Mohammad; Meigooni, Ali S.; Shahraini, Ramin

    2017-01-01

    Abstract Background Interstitial rotating shield brachytherapy (I-RSBT) is a recently developed method for treatment of prostate cancer. In the present study TG-43 dosimetric parameters of a 153Gd source were obtained for use in I-RSBT. Materials and methods A 153Gd source located inside a needle including a Pt shield and an aluminum window was simulated using MCNPX Monte Carlo code. Dosimetric parameters of this source model, including air kerma strength, dose rate constant, radial dose function and 2D anisotropy function, with and without the shields were calculated according to the TG-43 report. Results The air kerma strength was found to be 6.71 U for the non-shielded source with 1 GBq activity. This value was found to be 0.04 U and 6.19 U for the Pt shield and Al window cases, respectively. Dose rate constant for the non-shielded source was found to be 1.20 cGy/(hU). However, for a shielded source with Pt and aluminum window, dose rate constants were found to be 0.07 cGy/(hU) and 0.96 cGy/(hU), on the shielded and window sides, respectively. The values of radial dose function and anisotropy function were tabulated for these sources. Additionally, isodose curves were drawn for sources with and without shield, in order to evaluate the effect of shield on dose distribution. Conclusions Existence of the Pt shield may greatly reduce the dose to organs at risk and normal tissues which are located toward the shielded side. The calculated air kerma strength, dose rate constant, radial dose function and 2D anisotropy function data for the 153Gd source for the non-shielded and the shielded sources can be used in the treatment planning system (TPS). PMID:28265239

  14. Dosimetric Studies of Mixed Energy Intensity Modulated Radiation Therapy for Prostate Cancer Treatments

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    K. Abdul Haneefa

    2014-01-01

    Full Text Available Dosimetric studies of mixed field photon beam intensity modulated radiation therapy (IMRT for prostate cancer using pencil beam (PB and collapsed cone convolution (CCC algorithms using Oncentra MasterPlan treatment planning system (v. 4.3 are investigated in this study. Three different plans were generated using 6 MV, 15 MV, and mixed beam (both 6 and 15 MV. Fifteen patients with two sets of plans were generated: one by using PB and the other by using CCC for the same planning parameters and constraints except the beam energy. For each patient’s plan of high energy photons, one set of photoneutron measurements using solid state neutron track detector (SSNTD was taken for this study. Mean percentage of V66 Gy in the rectum is 18.55±2.8, 14.58±2.1, and 16.77±4.7 for 6 MV, 15 MV, and mixed-energy plans, respectively. Mean percentage of V66 Gy in bladder is 16.54±2.1, 17.42±2.1, and 16.94±41.9 for 6 MV, 15 MV, and mixed-energy plans, respectively. Mixed fields neutron contribution at the beam entrance surface is 45.62% less than at 15 MV photon beam. Our result shows that, with negligible neutron contributions, mixed field IMRT has considerable dosimetric advantage.

  15. Long-term results of a phase II trial of high-dose radiotherapy (60 Gy) and UFT/l-leucovorin in patients with non-resectable locally advanced rectal cancer (LARC)

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    Vestermark, Lene W.; Qvortrup, Camilla; Baatrup, Gunnar; Pfeiffer, Per (Odense Univ. Hospital, Odense (Denmark)); Bisgaard, Claus; Jacobsen, Anders (Vejle Hospital, Vejle (Denmark)); Hansen, Flemming; Rasmussen, Peter (Aarhus Univ. Hospital, Aarhus (Denmark))

    2008-03-15

    Background. Preoperative radiochemotherapy is a cornerstone in patients with non-resectable locally advanced rectal cancer (LARC). To improve outcome (number of R0 resections and survival) high-dose radiotherapy (RT) was combined with oral UFT/l-leucovorin to allow tumour regression before radical intended surgery. Methods. Pelvic RT was delivered with megavoltage photons using a 5 field technique. RT was CT-based, given 5 days a week through one posterior field and two lateral fields (48.6 Gy/27 fractions) to encompass the primary tumour and the regional lymph nodes. In addition, the tumour bed received a concurrent boost (5.4 Gy/27 fractions) and a final boost (6 Gy/3 fractions); thus GTV received 60 Gy/30 fractions. Concurrent with RT patients received a daily dose of oral UFT 300 mg/m2 plus l-leucovorin 22.5 mg 5/7days (divided in three doses). Results. From September 2000 to November 2004, 52 patients (median age 60 years (32-83); median PS 0 (0-2)) with LARC (36 primary, 16 recurrent) were included in this phase II study. All but three patients received the planned 60 Gy, median duration of RT was 42 days (25-49). Toxicity was very modest; only four patients had a dose reduction of UFT. No hematological toxicity of clinical significance was seen. Non-hematological toxicity grade 1 (GI-toxicity, fatigue and/or dysuria) was frequently observed but only four patients experienced grade 3 toxicity (diarrhoea and/or nausea/vomiting). Forty patients (77%) were operated (30 R0, 5 R1, 5 R2) median 55 days (27-112) after completion of RT. Seven (13%) patients had a pathological complete response (pCR). Thirty-one patients (60%) died after median 25.4 months (1.6-45.2 months). Twenty-one patients (40%) are still alive June 2007. Conclusions. Preoperative high-dose RT and concomitant UFT produces major regression in most patients with non-resectable LARC and thus a good chance of cure

  16. Investigating dosimetric effect of rotational setup errors in IMPT planning of synchronous bilateral lung cancer

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    Suresh Rana

    2015-12-01

    Full Text Available Purpose: The purpose of this study is to evaluate the dosimetric effect of rotational setup errors on the synchronous bi-lateral lung cancer plans generated by the intensity modulated proton therapy (IMPT technique.Methods: The original IMPT plans were generated in for the left planning target volume (PTV and right PTV of the left lung and right lung, respectively. Each plan was generated using two beams (lateral and posterior-anterior with an isocenter placed at the center of the corresponding PTV. The IMPT plans were optimized for a total dose of 74 Gy[RBE] prescribed to each PTV with 2 Gy(RBE per fraction. Original plans were recalculated by introducing simulated rotational errors. For each PTV, 18 rotational plans (±1⁰, ±2⁰, and ±3⁰ for each of the yaw, roll, and pitch rotations were generated. Results: Rotational errors caused the reduction in the clinical target volume (CTV and PTV coverage in new rotational IMPT plans when compared to the original IMPT lung plans. The CTV D99 was reduced by up to 13.3%, 9.1%, and 5.9% for the yaw (+3⁰, roll (-3⁰, and pitch (+3⁰, respectively. The PTV D95 was reduced by up to 8.7%, 7.3%, and 4.6% for the yaw (+3⁰, roll (-3⁰, and pitch (+3⁰, respectively. The PTV V100 showed the highest deviation with a reduction of dose coverage by up to 40.1%, 31.8%, and 33.9% for the yaw (-3⁰, roll (-3⁰, and pitch (+3⁰ respectively. Conclusion: The rotational setup errors with magnitude of ≥2⁰ can produce a significant loss of dose coverage to the target volume in the IMPT of a synchronous bi-lateral lung cancer. The yaw had the most severe impact on the dosimetric results when compared to other two rotational errors (roll and pitch.

  17. Effects of Dosimetrically Guided I-131 Therapy on Hematopoiesis in Patients With Differentiated Thyroid Cancer.

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    Bikas, Athanasios; Schneider, Mark; Desale, Sameer; Atkins, Frank; Mete, Mihriye; Burman, Kenneth D; Wartofsky, Leonard; Van Nostrand, Douglas

    2016-04-01

    A retrospective analysis was performed to evaluate the effects of dosimetrically-guided I-131 treatment on hematopoiesis. Statistically significant decreases in CBC parameters following a specific time-pattern were shown.

  18. Postoperative radiotherapy following mastectomy for patients with left-sided breast cancer: A comparative dosimetric study

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    Wang, Jiahao, E-mail: mashenglin@medmail.com.cn [Department of Radiation Oncology, Hangzhou Cancer Hospital, Hangzhou (China); Li, Xiadong; Deng, Qinghua [Department of Radiation Oncology, Hangzhou First People' s Hospital, Hangzhou (China); Xia, Bing; Wu, Shixiu [Department of Radiation Oncology, Hangzhou Cancer Hospital, Hangzhou (China); Liu, Jian [Department of Breast Surgery, Hangzhou First People' s Hospital, Hangzhou (China); Ma, Shenglin [Department of Radiation Oncology, Hangzhou First People' s Hospital, Hangzhou (China)

    2015-10-01

    The purposes of this article were to compare the biophysical dosimetry for postmastectomy left-sided breast cancer using 4 different radiotherapy (RT) techniques. In total, 30 patients with left-sided breast cancer were randomly selected for this treatment planning study. They were planned using 4 RT techniques, including the following: (1) 3-dimensional conventional tangential fields (TFs), (2) tangential intensity-modulated therapy (T-IMRT), (3) 4 fields IMRT (4F-IMRT), and (4) single arc volumetric-modulated arc therapy (S-VMAT). The planning target volume (PTV) dose was prescribed 50 Gy, the comparison of target dose distribution, conformity index, homogeneity index, dose to organs at risk (OARs), tumor control probability (TCP), normal tissue complication probability (NTCP), and number of monitor units (MUs) between 4 plans were investigated for their biophysical dosimetric difference. The target conformity and homogeneity of S-VMAT were better than the other 3 kinds of plans, but increased the volume of OARs receiving low dose (V{sub 5}). TCP of PTV and NTCP of the left lung showed no statistically significant difference in 4 plans. 4F-IMRT plan was superior in terms of target coverage and protection of OARs and demonstrated significant advantages in decreasing the NTCP of heart by 0.07, 0.03, and 0.05 compared with TFs, T-IMRT, and S-VMAT plan. Compared with other 3 plans, TFs reduced the average number of MUs. Of the 4 techniques studied, this analysis supports 4F-IMRT as the most appropriate balance of target coverage and normal tissue sparing.

  19. Dosimetric analysis and comparison of IMRT and HDR brachytherapy in treatment of localized prostate cancer.

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    Murali, V; Kurup, P G G; Mahadev, P; Mahalakshmi, S

    2010-04-01

    Radical radiotherapy is one of the options for the management of prostate cancer. In external beam therapy, 3D conformal radiotherapy (3DCRT) and intensity modulated radiotherapy (IMRT) are the options for delivery of increased radiation dose, as vital organs are very close to the prostate and a higher dose to these structures leads to an increased toxicity. In brachytherapy, low dose rate brachytherapy with permanent implant of radioactive seeds and high dose rate brachytherapy (HDR) with remote after loaders are available. A dosimetric analysis has been made on IMRT and HDR brachytherapy plans. Ten cases from each IMRT and HDR brachytherapy have been taken for the study. The analysis includes comparison of conformity and homogeneity indices, D100, D95, D90, D80, D50, D10 and D5 of the target. For the organs at risk (OAR), namely rectum and bladder, V100, V90 and V50 are compared. In HDR brachytherapy, the doses to 1 cc and 0.1 cc of urethra have also been studied. Since a very high dose surrounds the source, the 300% dose volumes in the target and within the catheters are also studied in two plans, to estimate the actual volume of target receiving dose over 300%. This study shows that the prescribed dose covers 93 and 92% of the target volume in IMRT and HDR brachytherapy respectively. HDR brachytherapy delivers a much lesser dose to OAR, compared to the IMRT. For rectum, the V50 in IMRT is 34.0cc whilst it is 7.5cc in HDR brachytherapy. With the graphic optimization tool in HDR brachytherapy planning, the dose to urethra could be kept within 120% of the target dose. Hence it is concluded that HDR brachytherapy may be the choice of treatment for cancer of prostate in the early stage.

  20. Dosimetric evaluation of simultaneous integrated boost during stereotactic body radiation therapy for pancreatic cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Wensha, E-mail: wensha.yang@cshs.org [Department of Radiation Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States); Reznik, Robert; Fraass, Benedick A. [Department of Radiation Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States); Nissen, Nicholas [Department of Surgery, Cedars Sinai Medical Center, Los Angeles, CA (United States); Hendifar, Andrew [Department of Gastrointestinal Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States); Wachsman, Ashley [Department of Cross-Sectional Imaging Interventional Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States); Sandler, Howard; Tuli, Richard [Department of Radiation Oncology, Cedars Sinai Medical Center, Los Angeles, CA (United States)

    2015-04-01

    Stereotactic body radiation therapy (SBRT) provides a promising way to treat locally advanced pancreatic cancer and borderline resectable pancreatic cancer. A simultaneous integrated boost (SIB) to the region of vessel abutment or encasement during SBRT has the potential to downstage otherwise likely positive surgical margins. Despite the potential benefit of using SIB-SBRT, the ability to boost is limited by the local geometry of the organs at risk (OARs), such as stomach, duodenum, and bowel (SDB), relative to tumor. In this study, we have retrospectively replanned 20 patients with 25 Gy prescribed to the planning target volume (PTV) and 33~80 Gy to the boost target volume (BTV) using an SIB technique for all patients. The number of plans and patients able to satisfy a set of clinically established constraints is analyzed. The ability to boost vessels (within the gross target volume [GTV]) is shown to correlate with the overlap volume (OLV), defined to be the overlap between the GTV + a 1(OLV1)- or 2(OLV2)-cm margin with the union of SDB. Integral dose, boost dose contrast (BDC), biologically effective BDC, tumor control probability for BTV, and normal tissue complication probabilities are used to analyze the dosimetric results. More than 65% of the cases can deliver a boost to 40 Gy while satisfying all OAR constraints. An OLV2 of 100 cm{sup 3} is identified as the cutoff volume: for cases with OLV2 larger than 100 cm{sup 3}, it is very unlikely the case could achieve 25 Gy to the PTV while successfully meeting all the OAR constraints.

  1. Intensity modulated radiotherapy versus volumetric modulated arc therapy in breast cancer: A comparative dosimetric analysis

    Directory of Open Access Journals (Sweden)

    KR Muralidhar

    2015-01-01

    Full Text Available Purpose: Intensity modulated radiotherapy (IMRT and volumetric modulated arc therapy (VMAT has the capacity to optimize the dose distribution. We analyzed the dosimetric differences of plans in treatment planning system (TPS between VMAT and IMRT in treating breast cancer. Methods: Fourteen patients were simulated, planned, and treated with VMAT using single, double or partial arcs. IMRT treatments were generated using 4 to 5 tangential IMRT fields for the same patients. All treatment plans were planned for 50 Gy in 25 fractions. The VMAT and IMRT plans were compared using the planning target volume (PTV dose and doses to the other organs at risk (OARs. Results: For the PTV, comparable minimum, mean, maximum, median, and modal dose as well equivalent sphere diameter of the structure (Equis were observed between VMAT and IMRT plans and found that these values were significantly equal in both techniques. The right lung mean and modal doses were considerably higher in VMAT plans while maximum value was considerably lower when compared with IMRT plans. The left lung mean and modal doses were higher with VMAT while maximum doses were higher in IMRT plans. The mean dose to the heart and maximum dose to the spinal cord was lower with IMRT. The mean dose to the body was higher in VMAT plans while the maximum dose was higher in IMRT plans. Conclusion: Four field tangential IMRT delivered comparable PTV dose with generally less dose to normal tissues in our breast cancer treatment study. The IMRT plans typically had more favourable dose characteristics to the lung, heart, and spinal cord and body dose when compared with VMAT. The only minor advantage of VMAT for breast cases was slightly better PTV coverage.

  2. Dosimetric analysis and comparison of IMRT and HDR brachytherapy in treatment of localized prostate cancer

    Directory of Open Access Journals (Sweden)

    Murali V

    2010-01-01

    Full Text Available Radical radiotherapy is one of the options for the management of prostate cancer. In external beam therapy, 3D conformal radiotherapy (3DCRT and intensity modulated radiotherapy (IMRT are the options for delivery of increased radiation dose, as vital organs are very close to the prostate and a higher dose to these structures leads to an increased toxicity. In brachytherapy, low dose rate brachytherapy with permanent implant of radioactive seeds and high dose rate brachytherapy (HDR with remote after loaders are available. A dosimetric analysis has been made on IMRT and HDR brachytherapy plans. Ten cases from each IMRT and HDR brachytherapy have been taken for the study. The analysis includes comparison of conformity and homogeneity indices, D100, D95, D90, D80, D50, D10 and D5 of the target. For the organs at risk (OAR, namely rectum and bladder, V100, V90 and V50 are compared. In HDR brachytherapy, the doses to 1 cc and 0.1 cc of urethra have also been studied. Since a very high dose surrounds the source, the 300% dose volumes in the target and within the catheters are also studied in two plans, to estimate the actual volume of target receiving dose over 300%. This study shows that the prescribed dose covers 93 and 92% of the target volume in IMRT and HDR brachytherapy respectively. HDR brachytherapy delivers a much lesser dose to OAR, compared to the IMRT. For rectum, the V50 in IMRT is 34.0cc whilst it is 7.5cc in HDR brachytherapy. With the graphic optimization tool in HDR brachytherapy planning, the dose to urethra could be kept within 120% of the target dose. Hence it is concluded that HDR brachytherapy may be the choice of treatment for cancer of prostate in the early stage.

  3. Volumetric modulated arc radiotherapy sparing the thyroid gland for early-stage glottic cancer: A dosimetrical analysis.

    Science.gov (United States)

    Kim, Eun Seok; Yeo, Seung-Gu

    2014-06-01

    Previous studies on advanced radiotherapy (RT) techniques for early stage glottic cancer have focused on sparing the carotid artery. However, the aim of the present study was to evaluate the dosimetric advantages of volumetric modulated arc therapy (VMAT) in terms of sparing the thyroid gland in early-stage glottic cancer patients. In total, 15 cT1N0M0 glottic cancer patients treated with definitive RT using VMAT were selected, and for dosimetric comparison, a conventional RT plan comprising opposed-lateral wedged fields was generated for each patient. The carotid artery, thyroid gland and spinal cord were considered organs at risk. The prescription dose was 63 Gy at 2.25 Gy per fraction. For the thyroid gland and carotid artery, all compared parameters were significantly lower with VMAT compared with conventional RT. For the thyroid gland, the median reduction rates of the mean dose (Dmean), the volume receiving ≥30% of the prescription dose (V30) and the V50 were 32.6, 40.9 and 46.0%, respectively. The Dmean was 14.7±2.6 Gy when using VMAT compared with 22.2±3.9 Gy when using conventional RT. The differences between the techniques in terms of planning target volume coverage and dose homogeneity were not significant. When considering a recent normal tissue complication probability model, which indicated the mean thyroid gland dose as the most significant predictor of radiation-induced hypothyroidism, the dosimetric advantage shown in this study may be valuable in reducing hypothyroidism following RT for early stage glottic cancer patients.

  4. Matched-pair analysis and dosimetric variations of two types of software for interstitial permanent brachytherapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ishiyama, Hiromichi, E-mail: hishiyam@kitasato-u.ac.jp [Department of Radiology, Kitasato University School of Medicine, Sagamihara, Kanagawa (Japan); Nakamura, Ryuji [Department of Radiology, Iwate Medical University, Morioka, Iwate (Japan); Satoh, Takefumi [Department of Urology, Kitasato University School of Medicine, Sagamihara, Kanagawa (Japan); Tanji, Susumu [Department of Urology, Iwate Medical University, Morioka, Iwate (Japan); Teh, Bin S. [Department of Radiation Oncology, The Methodist Hospital, Houston, TX (United States); Uemae, Mineko [Division of Radiation Oncology, Kitasato University Hospital, Sagamihara, Kanagawa (Japan); Baba, Shiro [Department of Urology, Kitasato University School of Medicine, Sagamihara, Kanagawa (Japan); Hayakawa, Kazushige [Department of Radiology, Kitasato University School of Medicine, Sagamihara, Kanagawa (Japan)

    2012-04-01

    The purpose of this study was to determine whether identical dosimetric results could be achieved using different planning software for permanent interstitial brachytherapy for prostate cancer. Data from 492 patients treated with brachytherapy were used for matched-pair analysis. Interplant and Variseed were used as software for ultrasound-based treatment planning. Institution, neoadjuvant hormonal therapy, prostate volume, and source strength were used for factors to match the 2 groups. The study population comprised of 126 patients with treatment planning using Interplant software and 127 matched patients using Variseed software. Dosimetric results were compared between the 2 groups. The Variseed group showed significantly higher values for dose covering 90% of prostate volume (pD90), prostate volume covered by 150% of prescription dose (pV150), and dose covering 30% of the urethra (uD30) compared with the Interplant group. Our results showed that use of different software could lead to different dosimetric results, which might affect the clinical outcomes.

  5. A dosimetric selectivity intercomparison of HDR brachytherapy, IMRT and helical tomotherapy in prostate cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Hermesse, Johanne; Biver, Sylvie; Jansen, Nicolas; Coucke, Philippe [Dept. of Radiation Oncology, Liege Univ. Hospital (Belgium); Lenaerts, Eric [Dept. of Medical Physics, Liege Univ. Hospital (Belgium); De Patoul, Nathalie; Vynckier, Stefaan [Dept. of Medical Physics, St Luc Univ. Hospital, Brussels (Belgium); Scalliet, Pierre [Dept. of Radiation Oncology, St Luc Univ. Hospital, Brussels (Belgium); Nickers, Philippe [Dept. of Radiation Oncology, Oscar Lambret Center, Lille (France)

    2009-11-15

    Background and purpose: dose escalation in order to improve the biochemical control in prostate cancer requires the application of irradiation techniques with high conformality. The dosimetric selectivity of three radiation modalities is compared: high-dose-rate brachytherapy (HDR-BT), intensity-modulated radiation radiotherapy (IMRT), and helical tomotherapy (HT). Patients and methods: ten patients with prostate adenocarcinoma treated by a 10-Gy HDR-BT boost after external-beam radiotherapy were investigated. For each patient, HDR-BT, IMRT and HT theoretical treatment plans were realized using common contour sets. A 10-Gy dose was prescribed to the planning target volume (PTV). The PTVs and critical organs' dose-volume histograms obtained were compared using Student's t-test. Results: HDR-BT delivers spontaneously higher mean doses to the PTV with smaller cold spots compared to IMRT and HT. 33% of the rectal volume received a mean HDR-BT dose of 3.86 {+-} 0.3 Gy in comparison with a mean IMRT dose of 6.57 {+-} 0.68 Gy and a mean HT dose of 5.58 {+-} 0.71 Gy (p < 0.0001). HDR-BT also enables to better spare the bladder. The hot spots inside the urethra are greater with HDR-BT. The volume of healthy tissue receiving 10% of the prescribed dose is reduced at least by a factor of 8 with HDR-BT (p < 0.0001). Conclusion: HDR-BT offers better conformality in comparison with HT and IMRT and reduces the volume of healthy tissue receiving a low dose. (orig.)

  6. Dosimetric evaluation of three adaptive strategies for prostate cancer treatment including pelvic lymph nodes irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cantin, Audrey; Gingras, Luc; Archambault, Louis, E-mail: louis.archambault@phy.ulaval.ca [Département de Physique, de génie Physique et d’optique et Centre de Recherche sur le Cancer, Université Laval, Québec, Québec G1V 0A6, Canada and Département de Radio-Oncologie et Centre de Recherche du CHU de Québec, CHU de Québec—Université Laval, 11 côte du Palais, Québec, Québec G1R 2J6 (Canada); Lachance, Bernard; Foster, William [Département de Radio-Oncologie et Centre de Recherche du CHU de Québec, CHU de Québec—Université Laval, 11 côte du Palais, Québec, Québec G1R 2J6 (Canada); Goudreault, Julie [Département de Radio-Oncologie et Centre de Recherche du CHU de Québec, CHU de Québec—Université Laval, 11 côte du Palais, Québec, Québec G1R 2J6, Canada and Département de Radio-Oncologie, CSSS de Gatineau–Hôpital de Gatineau, 909 Boulevard La Vérendrye, Gatineau, Québec J8P 7H2 (Canada)

    2015-12-15

    Purpose: The movements of the prostate relative to the pelvic lymph nodes during intensity-modulated radiation therapy treatment can limit margin reduction and affect the protection of the organs at risk (OAR). In this study, the authors performed an analysis of three adaptive treatment strategies that combine information from both bony and gold marker registrations. The robustness of those treatments against the interfraction prostate movements was evaluated. Methods: A retrospective study was conducted on five prostate cancer patients with 7–13 daily cone-beam CTs (CBCTs). The clinical target volumes (CTVs) consisting of pelvic lymph nodes, prostate, and seminal vesicles as well as the OARs were delineated on each CBCT and the initial CT. Three adaptive strategies were analyzed. Two of these methods relied on a two-step patient positioning at each fraction. First step: a bony registration was used to deliver the nodal CTV prescription. Second step: a gold marker registration was then used either to (1) complete the dose delivered to the prostate (complement); (2) or give almost the entire prescription to the prostate with a weak dose gradient between the targets to compensate for possible motions (gradient). The third method (COR) used a pool of precalculated plans based on images acquired at previous treatment fractions. At each new fraction, a plan is selected from that pool based on the daily position of prostate center-of-mass. The dosimetric comparison was conducted and results are presented with and without the systematic shift in the prostate position on the CT planning. The adaptive strategies were compared to the current clinical standard where all fractions are treated with the initial nonadaptive plan. Results: The minimum daily prostate D{sub 95%} is improved by 2%, 9%, and 6% for the complement, the gradient, and the COR approaches, respectively, compared to the nonadaptive method. The average nodal CTV D{sub 95%} remains constant across the

  7. Comparison of the dose distribution obtained from dosimetric systems with intensity modulated radiotherapy planning system in the treatment of prostate cancer

    Science.gov (United States)

    Gökçe, M.; Uslu, D. Koçyiǧit; Ertunç, C.; Karalı, T.

    2016-03-01

    The aim of this study is to compare Intensity Modulated Radiation Therapy (IMRT) plan of prostate cancer patients with different dose verification systems in dosimetric aspects and to compare these systems with each other in terms of reliability, applicability and application time. Dosimetric control processes of IMRT plan of three prostate cancer patients were carried out using thermoluminescent dosimeter (TLD), ion chamber (IC) and 2D Array detector systems. The difference between the dose values obtained from the dosimetric systems and treatment planning system (TPS) were found to be about % 5. For the measured (TLD) and calculated (TPS) doses %3 percentage differences were obtained for the points close to center while percentage differences increased at the field edges. It was found that TLD and IC measurements will increase the precision and reliability of the results of 2D Array.

  8. Postoperative intensity modulated radiation therapy in high risk prostate cancer: a dosimetric comparison.

    Science.gov (United States)

    Digesú, Cinzia; Cilla, Savino; De Gaetano, Andrea; Massaccesi, Mariangela; Macchia, Gabriella; Ippolito, Edy; Deodato, Francesco; Panunzi, Simona; Iapalucci, Chiara; Mattiucci, Gian Carlo; D'Angelo, Elisa; Padula, Gilbert D A; Valentini, Vincenzo; Cellini, Numa; Piermattei, Angelo; Morganti, Alessio G

    2011-01-01

    The aim of this study was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal technique (3D-CRT), with respect to target coverage and irradiation of organs at risk for high dose postoperative radiotherapy (PORT) of the prostate fossa. 3D-CRT and IMRT treatment plans were compared with respect to dose to the rectum and bladder. The dosimetric comparison was carried out in 15 patients considering 2 different scenarios: (1) exclusive prostate fossa irradiation, and (2) pelvic node irradiation followed by a boost on the prostate fossa. In scenario (1), a 3D-CRT plan (box technique) and an IMRT plan were calculated and compared for each patient. In scenario (2), 3 treatment plans were calculated and compared for each patient: (a) 3D-CRT box technique for both pelvic (prophylactic nodal irradiation) and prostate fossa irradiation (3D-CRT only); (b) 3D-CRT box technique for pelvic irradiation followed by an IMRT boost to the prostatic fossa (hybrid 3D-CRT and IMRT); and (c) IMRT for both pelvic and prostate fossa irradiation (IMRT only). For exclusive prostate fossa irradiation, IMRT significantly reduced the dose to the rectum (lower Dmean, V50%, V75%, V90%, V100%, EUD, and NTCP) and the bladder (lower Dmean, V50%, V90%, EUD and NTCP). When prophylactic irradiation of the pelvis was also considered, plan C (IMRT only) performed better than plan B (hybrid 3D-CRT and IMRT) as respect to both rectum and bladder irradiation (reduction of Dmean, V50%, V75%, V90%, equivalent uniform dose [EUD], and normal tissue complication probability [NTCP]). Plan (b) (hybrid 3D-CRT and IMRT) performed better than plan (a) (3D-CRT only) with respect to dose to the rectum (lower Dmean, V75%, V90%, V100%, EUD, and NTCP) and the bladder (Dmean, EUD, and NTCP). Postoperative IMRT in prostate cancer significantly reduces rectum and bladder irradiation compared with 3D-CRT.

  9. Dosimetric impact of mixed-energy volumetric modulated arc therapy plans for high-risk prostate cancer

    Directory of Open Access Journals (Sweden)

    Shyam Pokharel

    2013-10-01

    Full Text Available Purpose: This study investigated the dosimetric impact of mixing low and high energy treatment plans for prostate cancer treated with volumetric modulated arc therapy (VMAT technique in the form of RapidArc.Methods: A cohort of 12 prostate cases involving proximal seminal vesicles and lymph nodes was selected for this retrospective study. For each prostate case, the single-energy plans (SEPs and mixed-energy plans (MEPs were generated.  First, the SEPs were created using 6 mega-voltage (MV energy for both the primary and boost plans. Second, the MEPs were created using 16 MV energy for the primary plan and 6 MV energy for the boost plan. The primary and boost MEPs used identical beam parameters and same dose optimization values as in the primary and boost SEPs for the corresponding case. The dosimetric parameters from the composite plans (SEPs and MEPs were evaluated. Results: The dose to the target volume was slightly higher (on average <1% in the SEPs than in the MEPs. The conformity index (CI and homogeneity index (HI values between the SEPs and MEPs were comparable. The dose to rectum and bladder was always higher in the SEPs (average difference up to 3.7% for the rectum and up to 8.4% for the bladder than in the MEPs. The mean dose to femoral heads was higher by about 0.8% (on average in the MEPs than in the SEPs. The number of monitor units and integral dose were higher in the SEPs compared to the MEPs by average differences of 9.1% and 5.5%, respectively.Conclusion: The preliminary results from this study suggest that use of mixed-energy VMAT plan for high-risk prostate cancer could potentially reduce the integral dose and minimize the dose to rectum and bladder, but for the higher femoral head dose.-----------------------------------------------Cite this article as:Pokharel S. Dosimetric impact of mixed-energy volumetric modulated arc therapy plans for high-risk prostate cancer. Int J Cancer Ther Oncol 2013;1(1:01011.DOI: http

  10. A dosimetric comparison of 3D conformal vs intensity modulated vs volumetric arc radiation therapy for muscle invasive bladder cancer

    Directory of Open Access Journals (Sweden)

    Foroudi Farshad

    2012-07-01

    Full Text Available Abstract Background To compare 3 Dimensional Conformal radiotherapy (3D-CRT with Intensity Modulated Radiotherapy (IMRT with Volumetric-Modulated Arc Therapy (VMAT for bladder cancer. Methods Radiotherapy plans for 15 patients with T2-T4N0M0 bladder cancer were prospectively developed for 3-DCRT, IMRT and VMAT using Varian Eclipse planning system. The same radiation therapist carried out all planning and the same clinical dosimetric constraints were used. 10 of the patients with well localised tumours had a simultaneous infield boost (SIB of the primary tumour planned for both IMRT and VMAT. Tumour control probabilities and normal tissue complication probabilities were calculated. Results Mean planning time for 3D-CRT, IMRT and VMAT was 30.0, 49.3, and 141.0 minutes respectively. The mean PTV conformity (CI index for 3D-CRT was 1.32, for IMRT 1.05, and for VMAT 1.05. The PTV Homogeneity (HI index was 0.080 for 3D-CRT, 0.073 for IMRT and 0.086 for VMAT. Tumour control and normal tissue complication probabilities were similar for 3D-CRT, IMRT and VMAT. The mean monitor units were 267 (range 250–293 for 3D-CRT; 824 (range 641–1083 for IMRT; and 403 (range 333–489 for VMAT (P  Conclusions VMAT is associated with similar dosimetric advantages as IMRT over 3D-CRT for muscle invasive bladder cancer. VMAT is associated with faster delivery times and less number of mean monitor units than IMRT. SIB is feasible in selected patients with localized tumours.

  11. Long-term results of a phase II trial of high-dose radiotherapy (60 Gy) and UFT/l-leucovorin in patients with non-resectable locally advanced rectal cancer (LARC)

    DEFF Research Database (Denmark)

    Vestermark, Lene W; Jakobsen, Anders; Qvortrup, Camilla;

    2008-01-01

    , 52 patients (median age 60 years (32-83); median PS 0 (0-2)) with LARC (36 primary, 16 recurrent) were included in this phase II study. All but three patients received the planned 60 Gy, median duration of RT was 42 days (25-49). Toxicity was very modest; only four patients had a dose reduction...

  12. Dose-to-medium vs. dose-to-water: Dosimetric evaluation of dose reporting modes in Acuros XB for prostate, lung and breast cancer

    Directory of Open Access Journals (Sweden)

    Suresh Rana

    2014-12-01

    Full Text Available Purpose: Acuros XB (AXB dose calculation algorithm is available for external beam photon dose calculations in Eclipse treatment planning system (TPS. The AXB can report the absorbed dose in two modes: dose-to-water (Dw and dose-to-medium (Dm. The main purpose of this study was to compare the dosimetric results of the AXB_Dm with that of AXB_Dw on real patient treatment plans. Methods: Four groups of patients (prostate cancer, stereotactic body radiation therapy (SBRT lung cancer, left breast cancer, and right breast cancer were selected for this study, and each group consisted of 5 cases. The treatment plans of all cases were generated in the Eclipse TPS. For each case, treatment plans were computed using AXB_Dw and AXB_Dm for identical beam arrangements. Dosimetric evaluation was done by comparing various dosimetric parameters in the AXB_Dw plans with that of AXB_Dm plans for the corresponding patient case. Results: For the prostate cancer, the mean planning target volume (PTV dose in the AXB_Dw plans was higher by up to 1.0%, but the mean PTV dose was within ±0.3% for the SBRT lung cancer. The analysis of organs at risk (OAR results in the prostate cancer showed that AXB_Dw plans consistently produced higher values for the bladder and femoral heads but not for the rectum. In the case of SBRT lung cancer, a clear trend was seen for the heart mean dose and spinal cord maximum dose, with AXB_Dw plans producing higher values than the AXB_Dm plans. However, the difference in the lung doses between the AXB_Dm and AXB_Dw plans did not always produce a clear trend, with difference ranged from -1.4% to 2.9%. For both the left and right breast cancer, the AXB_Dm plans produced higher maximum dose to the PTV for all cases. The evaluation of the maximum dose to the skin showed higher values in the AXB_Dm plans for all 5 left breast cancer cases, whereas only 2 cases had higher maximum dose to the skin in the AXB_Dm plans for the right breast cancer

  13. Organ motion study and dosimetric impact of respiratory gating radiotherapy for esophageal cancer; Etude de mobilite organique et impact dosimetrique de l'asservissement respiratoire dans la radiotherapie des cancers de l'oesophage

    Energy Technology Data Exchange (ETDEWEB)

    Lorchel, F

    2007-04-15

    Chemoradiotherapy is now the standard treatment for locally advanced or inoperable esophageal carcinoma. In this indication, conformal radiotherapy is generally used. However, prognosis remains poor for these patients. Respiratory gating radiotherapy can decrease healthy tissues irradiation and allows escalation dose in lung, liver and breast cancer. In order to improve radiotherapy technique, we propose to study the feasibility of respiratory gating for esophageal cancer. We will study the respiratory motions of esophageal cancer to optimize target volume delineation, especially the internal margin (I.M.). We will test the correlation between tumour and chest wall displacements to prove that esophageal cancer motions are induced by respiration. This is essential before using free breathing respiratory gating systems. We will work out the dosimetric impact of respiratory gating using various dosimetric analysis parameters. We will compare dosimetric plans at end expiration, end inspiration and deep inspiration with dosimetric plan in free-breathing condition. This will allow us to establish the best respiratory phase to irradiate for each gating system. This dosimetric study will be completed with linear quadratic equivalent uniform dose (E.U.D.) calculation for each volume of interest. Previously, we will do a theoretical study of histogram dose volume gradation to point up its use. (author)

  14. Dosimetric study comparing intensity modulated and conformal pelvic radiotherapy boost plans in locally advanced cancer cervix in NCI-Cairo

    Institute of Scientific and Technical Information of China (English)

    Mohamed Mahmoud; Hesham A. EL-Hossiny; Nashaat A. Diab; Mahmoud Shosha

    2013-01-01

    Objective: This study was to compare 5 field conformal technique to the intensity modulated radiotherapy (IMRT) 8 fields technique in boosting locally advanced cancer cervix cases after external beam radiotherapy with respect to target volume coverage and dose to normal tissues. Methods: We conducted a single institutional comparative dosimetric analysis of 10 patients with cancer cervix who was presented to radiotherapy department in National Cancer Institute, Cairo in period between June 2012 to September 2012 and received a CRT boost in the place of planned brachytherapy after large field pelvic radiotherapy (PRT) with concurrent chemotherapy were retrospectively identified. All tumors were situated in the low central pelvis. Two plans were done for every patient; one using the 8 fields IMRT and the second one using 5 fields' 3DCRT the two techniques were then compared using dose volume histogram (DVH) analysis for the PTV, bladder, rectum and both femoral heads. Results: Comparing different DVHs, it was found that the planning target volume (PTV) was adequately covered in both plans while it was demonstrates that the 8 fields IMRT technique carried less doses reaching OARs (rectum, bladder, both femoral heads). Conclusion: From the present study, it is concluded that IMRT technique spared more efficiently OARs than CRT technique but both techniques covered the PTV adequately so whenever possible IMRT technique should be used.

  15. Dosimetric Feasibility of Dose Escalation Using SBRT Boost for Stage III Non-Small Cell Lung Cancer

    Science.gov (United States)

    Hepel, Jaroslaw T.; Peter, Justin; Hiatt, Jessica R.; Patel, Salil; Osibanjo, Oluwademilade; Safran, Howard; Curran, Bruce; DiPetrillo, Thomas

    2012-01-01

    Purpose: Standard chemoradiation therapy for stage III non-small cell lung cancer (NSCLCa) results in suboptimal outcomes with a high rate of local failure and poor overall survival. We hypothesize that dose escalation using stereotactic body radiotherapy (SBRT) boost could improve upon these results. We present here a study evaluating the dosimetric feasibility of such an approach. Methods: Anonymized CT data sets from five randomly selected patients with stage III NSCLCa undergoing definitive chemoradiation therapy in our department with disease volumes appropriate for SBRT boost were selected. Three-dimensional conformal radiation therapy (3D-CRT) plans to 50.4 Gy in 28 fractions were generated follow by SBRT plans to two dose levels, 16 Gy in two fractions and 28 Gy in two fractions. SBRT plans and total composite (3D-CRT and SBRT) were optimized and evaluated for target coverage and dose to critical structures; lung, esophagus, cord, and heart. Results: All five plans met predetermined target coverage and normal tissue dose constraints. PTV V95 was equal to or greater than 95% in all cases. The cumulative lung V20 and V5 of the combined 3D-CRT and SBRT plans were less than or equal to 30 and 55%, respectively. The 5 cc esophageal dose was less than 12 Gy for all low and high dose SBRT plans. The cumulative dose to the esophagus was also acceptable with less than 10% of the esophagus receiving doses in excess of 50 Gy. The cumulative spinal cord dose was less than 33 Gy and heart V25 was less than 5%. Conclusion: The combination of chemoradiation to 50.4 Gy followed by SBRT boost to gross disease at the primary tumor and involved regional lymph nodes is feasible with respect to normal tissue dose constraints in this dosimetric pilot study. A phase I/II trial to evaluate the clinical safety and efficacy of this approach is being undertaken. PMID:23057009

  16. Dosimetric and technical aspects of intraoperative I-125 brachytherapy for stage I non-small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Mark [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Colonias, Athanasios [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Parda, David [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Trombetta, Mark [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Gayou, Olivier [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Reitz, Bodo [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States); Miften, Moyed [Department of Radiation Oncology, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212 (United States)

    2007-03-07

    Initial treatment outcome data from our institution for stage I non-small cell lung cancer (NSCLC) patients have shown that sublobar resection in combination with iodine-125 (I-125) brachytherapy is associated with recurrence rates of 2.0%, compared to 18.6% with sublobar resection alone. In this work, the technical and dosimetric aspects required to execute this procedure from the radiation oncology perspective as well as an analysis of the dose distributions of patients treated with this technique are presented. In this treatment technique, I-125 seeds in vicryl suture are embedded into vicryl mesh and surgically inserted providing a 2.0 cm margin on each side of the resection staple line. A nomogram is developed to determine the suture spacing in the vicryl mesh, as a function of seed activity in order to deliver 120 Gy at a distance of 0.5 cm above and below the seed array. Post-operative dosimetry consists of a CT-based planning and dose volume analysis. Dose distributions, dose volume histograms and mean dose data for lung are analysed in a group of patients. Dosimetric results show significant lung sparing with only a small volume of lung irradiated for all patients with mean lung dose values ranging from 1.5 Gy to 5.4 Gy. Lung brachytherapy with I-125 at the time of sublobar resection is a highly conformal option of dose delivery for stage I NSCLC patients with compromised physiologic reserve. Patient-related toxicity clinically measured by loss of pulmonary function and radiation-induced pneumonitis have not been linked to this procedure.

  17. Dosimetric and technical aspects of intraoperative I-125 brachytherapy for stage I non-small cell lung cancer

    Science.gov (United States)

    Johnson, Mark; Colonias, Athanasios; Parda, David; Trombetta, Mark; Gayou, Olivier; Reitz, Bodo; Miften, Moyed

    2007-03-01

    Initial treatment outcome data from our institution for stage I non-small cell lung cancer (NSCLC) patients have shown that sublobar resection in combination with iodine-125 (I-125) brachytherapy is associated with recurrence rates of 2.0%, compared to 18.6% with sublobar resection alone. In this work, the technical and dosimetric aspects required to execute this procedure from the radiation oncology perspective as well as an analysis of the dose distributions of patients treated with this technique are presented. In this treatment technique, I-125 seeds in vicryl suture are embedded into vicryl mesh and surgically inserted providing a 2.0 cm margin on each side of the resection staple line. A nomogram is developed to determine the suture spacing in the vicryl mesh, as a function of seed activity in order to deliver 120 Gy at a distance of 0.5 cm above and below the seed array. Post-operative dosimetry consists of a CT-based planning and dose volume analysis. Dose distributions, dose volume histograms and mean dose data for lung are analysed in a group of patients. Dosimetric results show significant lung sparing with only a small volume of lung irradiated for all patients with mean lung dose values ranging from 1.5 Gy to 5.4 Gy. Lung brachytherapy with I-125 at the time of sublobar resection is a highly conformal option of dose delivery for stage I NSCLC patients with compromised physiologic reserve. Patient-related toxicity clinically measured by loss of pulmonary function and radiation-induced pneumonitis have not been linked to this procedure.

  18. Treatment plan comparison of Linac step and shoot,Tomotherapy, RapidArc, and Proton therapy for prostate cancer using dosimetrical and biological index

    CERN Document Server

    Lee, Suk; Chang, Kyung Hwan; Shim, Jang Bo; Kim, Kwang Hyeon; Lee, Nam Kwon; Park, Young Je; Kim, Chul Yong; Cho, Sam Ju; Lee, Sang Hoon; Min, Chul Kee; Kim, Woo Chul; Cho, Kwang Hwan; Huh, Hyun Do; Lim, Sangwook; Shin, Dongho

    2015-01-01

    The purpose of this study was to use various dosimetrical indices to determine the best IMRT modality technique for treating patients with prostate cancer. Ten patients with prostate cancer were included in this study. Intensity modulated radiation therapy plans were designed to include different modalities, including the linac step and shoot, Tomotherapy, RapidArc, and Proton systems. Various dosimetrical indices, like the prescription isodose to target volume (PITV) ratio, conformity index (CI), homogeneity index (HI), target coverage index (TCI), modified dose homogeneity index (MHI), conformation number (CN), critical organ scoring index (COSI), and quality factor (QF) were determined to compare the different treatment plans. Biological indices such as the generalized equivalent uniform dose (gEUD), based tumor control probability (TCP), and normal tissue complication probability (NTCP) were also calculated and used to compare the treatment plans. The RapidArc plan attained better PTV coverage, as evidenc...

  19. SU-E-J-169: The Dosimetric and Temporal Effects of Respiratory-Gated Radiation Therapy in Lung Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Rouabhi, O; Gross, B; Xia, J [University of Iowa, Iowa City, Iowa (United States); Bayouth, J [University of Wisconsin, Madison, WI (United States)

    2015-06-15

    Purpose: To evaluate the dosimetric and temporal effects of high dose rate treatment mode for respiratory-gated radiation therapy in lung cancer patients. Methods: Treatment plans from five lung cancer patients (3 nongated (Group 1), 2 gated at 80EX-80IN (Group 2)) were retrospectively evaluated. The maximum tumor motions range from 6–12 mm. Using the same planning criteria, four new treatment plans, corresponding to four gating windows (20EX–20IN, 40EX–40IN, 60EX–60IN, and 80EX–80IN), were generated for each patient. Mean tumor dose (MTD), mean lung dose (MLD), and lung V20 were used to assess the dosimetric effects. A MATLAB algorithm was developed to compute treatment time by considering gantry rotation time, time to position collimator leaves, dose delivery time (scaled relative to the gating window), and communication overhead. Treatment delivery time for each plan was estimated using a 500 MU/min dose rate for the original plans and a 1500 MU/min dose rate for the gated plans. Results: Differences in MTD were less than 1Gy across plans for all five patients. MLD and lung V20 were on average reduced between −16.1% to −6.0% and −20.0% to −7.2%, respectively for non-gated plans when compared with the corresponding gated plans, and between − 5.8% to −4.2% and −7.0% to −5.4%, respectively for plans originally gated at 80EX–80IN when compared with the corresponding 20EX-20IN to 60EX– 60IN gated plans. Treatment delivery times of gated plans using high dose rate were reduced on average between −19.7% (−1.9min) to −27.2% (−2.7min) for originally non-gated plans and −15.6% (−0.9min) to −20.3% (−1.2min) for originally 80EX-80IN gated plans. Conclusion: Respiratory-gated radiation therapy in lung cancer patients can reduce lung toxicity, while maintaining tumor dose. Using a gated high-dose-rate treatment, delivery time comparable to non-gated normal-dose-rate treatment can be achieved. This research is supported by Siemens

  20. Dosimetric comparison of treatment techniques IMRT and VMAT for breast cancer; Comparacion dosimetrica de las tecnicas de tratamiento IMRT y VMAT para cancer en mama

    Energy Technology Data Exchange (ETDEWEB)

    Urbina, G. L. [Universidad Nacional de Ingenieria, Maestria en Fisica Medica, Av. Tupac Amaru s/n, Rimac, Lima 25 (Peru); Garcia, B. G., E-mail: gerlup@hotmail.com [Red AUNA, Clinica Delgado, Av. Angamos Cdra. 4 esquina Gral. Borgono, Miraflores, Lima (Peru)

    2015-10-15

    In this study the dosimetric distribution was compared in the different treatment techniques such as Volumetric Modulated Arc Therapy (VMAT) and Intensity Modulated Radiation Therapy (IMRT) in female patients with breast cancer with stage II-B and III-A, 6 cases (both calculated on VMAT and IMRT) were studied, comparison parameter that are taken into account are: compliance rate, homogeneity index, monitor units, volume dose 50 Gy (D-50%) and 5 Gy (D-5%) volume dose. Comparisons are made in primary tumor volume to optimize treatment in patients with breast cancer, with IMRT using Step, Shoot and VMAT Monte Carlo algorithm, in addition to the organs at risk; the concern to make this work is due to technological advances in radiotherapy and the application of new treatment techniques, that increase the accuracy allowing treatment dose climbing delivering a higher dose to the patient. (Author)

  1. Dosimetric Predictors of Radiation-induced Acute Nausea and Vomiting in IMRT for Nasopharyngeal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Victor H.F., E-mail: vhflee@hku.hk [Department of Clinical Oncology, University of Hong Kong, Queen Mary Hospital (Hong Kong); Ng, Sherry C.Y.; Leung, T.W.; Au, Gordon K.H.; Kwong, Dora L.W. [Department of Clinical Oncology, University of Hong Kong, Queen Mary Hospital (Hong Kong)

    2012-09-01

    Purpose: We wanted to investigate dosimetric parameters that would predict radiation-induced acute nausea and vomiting in intensity-modulated radiation therapy (IMRT) for undifferentiated carcinoma of the nasopharynx (NPC). Methods and Materials: Forty-nine consecutive patients with newly diagnosed NPC were treated with IMRT alone in this prospective study. Patients receiving any form of chemotherapy were excluded. The dorsal vagal complex (DVC) as well as the left and right vestibules (VB-L and VB-R, respectively) were contoured on planning computed tomography images. A structure combining both the VB-L and the VB-R, named VB-T, was also generated. All structures were labeled organs at risk (OAR). A 3-mm three-dimensional margin was added to these structures and labeled DVC+3 mm, VB-L+3 mm, VB-R+3 mm, and VB-T+3 mm to account for physiological body motion and setup error. No weightings were given to these structures during optimization in treatment planning. Dosimetric parameters were recorded from dose-volume histograms. Statistical analysis of parameters' association with nausea and vomiting was performed using univariate and multivariate logistic regression. Results: Six patients (12.2%) reported Grade 1 nausea, and 8 patients (16.3%) reported Grade 2 nausea. Also, 4 patients (8.2%) complained of Grade 1 vomiting, and 4 patients (8.2%) experienced Grade 2 vomiting. No patients developed protracted nausea and vomiting after completion of IMRT. For radiation-induced acute nausea, V40 (percentage volume receiving at least 40Gy) to the VB-T and V40>=80% to the VB-T were predictors, using univariate analysis. On multivariate analysis, V40>=80% to the VB-T was the only predictor. There were no predictors of radiation-induced acute vomiting, as the number of events was too small for analysis. Conclusions: This is the first study demonstrating that a V40 to the VB-T is predictive of radiation-induced acute nausea. The vestibules should be labeled as sensitive OARs

  2. Adhesive evaluation of thin films of LARC-TPI and LARC-TPI with 5 mol % ODA

    Science.gov (United States)

    Progar, D. J.

    1986-01-01

    A commercially available LARC-TPI film and an experimentally prepared film of LARC-TPI with 5 mol % of 4,4'-oxydianiline (ODA), designated as LARC-TPI/ODA in the report, supplied by Mitsui Toatsu Chemicals, Incorporated (MTCI), Japan, were evaluated as thermoplastic adhesive films for bonding Ti-6Al-4V. The LARC-TPI/ODA had been shown by MTCI to possess more flow than thermoplastic LARC-TPI and was, therefore, evaluated and compared to the LARC-TPI. Lap shear strength was used to evaluate the materials as adhesives. They were characterized after fracture by determining the glass transition temperature, Tg. The mode of failure was also reported. Thermal exposure at 204C for 500 and 1000 hrs and a 72-hour water-boil were conducted on lap shear specimens prepared with the two adhesive films. Lap shear tests were conducted at RT, 177C, 204C, and 232C before and after exposures.

  3. Forward-planned intensity modulated radiation therapy using a cobalt source: A dosimetric study in breast cancer

    Directory of Open Access Journals (Sweden)

    Savino Cilla

    2013-01-01

    Full Text Available This analysis evaluates the feasibility and dosimetric results of a simplified intensity-modulated radiotherapy (IMRT treatment using a cobalt-therapy unit for post-operative breast cancer. Fourteen patients were included. Three plans per patient were produced by a cobalt-60 source: A standard plan with two wedged tangential beams, a standard tangential plan optimized without the use of wedges and a plan based on the forward-planned "field-in-field" IMRT technique (Co-FinF where the dose on each of the two tangential beams was split into two different segments and the two segments weight was determined with an iterative process. For comparison purposes, a 6-MV photon standard wedged tangential treatment plan was generated. D mean , D 98% , D 2% , V 95% , V 107%, homogeneity, and conformity indices were chosen as parameters for comparison. Co-FinF technique improved the planning target volume dose homogeneity compared to other cobalt-based techniques and reduced maximum doses (D 2% and high-dose volume (V 110% . Moreover, it showed a better lung and heart dose sparing with respect to the standard approach. The higher dose homogeneity may encourage the adoption of accelerated-hypofractionated treatments also with the cobalt sources. This approach can promote the spread of breast conservative treatment in developing countries.

  4. Dosimetric and geometric evaluation of a hybrid strategy of offline adaptive planning and online image guidance for prostate cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Liu Han; Wu Qiuwen, E-mail: Qiuwen.Wu@Duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States)

    2011-08-07

    For prostate cancer patients, online image-guided (IG) radiotherapy has been widely used in clinic to correct the translational inter-fractional motion at each treatment fraction. For uncertainties that cannot be corrected online, such as rotation and deformation of the target volume, margins are still required to be added to the clinical target volume (CTV) for the treatment planning. Offline adaptive radiotherapy has been implemented to optimize the treatment for each individual patient based on the measurements at early stages of treatment process. It has been shown that offline adaptive radiotherapy can effectively reduce the required margin. Recently a hybrid strategy of offline adaptive replanning and online IG was proposed and the geometric evaluation was performed. It was found that the planning margins can further be reduced by 1-2 mm compared to online IG only strategy. The purpose of this study was to investigate the dosimetric benefits of such a hybrid strategy on the target and organs at risk. A total of 420 repeated helical computed tomography scans from 28 patients were included in the study. Both low-risk patients (LRP, CTV = prostate) and intermediate-risk patients (IRP, CTV = prostate + seminal vesicles, SV) were included in the simulation. Two registration methods, based on center-of-mass shift of prostate only and prostate plus SV, were performed for IRP. The intensity-modulated radiotherapy was used in the simulation. Criteria on both cumulative and fractional doses were evaluated. Furthermore, the geometric evaluation was extended to investigate the optimal number of fractions necessary to construct the internal target volume (ITV) for the hybrid strategy. The dosimetric margin improvement was smaller than its geometric counterpart and was in the range of 0-1 mm. The optimal number of fractions necessary for the ITV construction is 2 for LRPs and 3-4 for IRPs in a hypofractionation protocol. A new cumulative index of target volume was proposed

  5. Dosimetric and geometric evaluation of a hybrid strategy of offline adaptive planning and online image guidance for prostate cancer radiotherapy

    Science.gov (United States)

    Liu, Han; Wu, Qiuwen

    2011-08-01

    For prostate cancer patients, online image-guided (IG) radiotherapy has been widely used in clinic to correct the translational inter-fractional motion at each treatment fraction. For uncertainties that cannot be corrected online, such as rotation and deformation of the target volume, margins are still required to be added to the clinical target volume (CTV) for the treatment planning. Offline adaptive radiotherapy has been implemented to optimize the treatment for each individual patient based on the measurements at early stages of treatment process. It has been shown that offline adaptive radiotherapy can effectively reduce the required margin. Recently a hybrid strategy of offline adaptive replanning and online IG was proposed and the geometric evaluation was performed. It was found that the planning margins can further be reduced by 1-2 mm compared to online IG only strategy. The purpose of this study was to investigate the dosimetric benefits of such a hybrid strategy on the target and organs at risk. A total of 420 repeated helical computed tomography scans from 28 patients were included in the study. Both low-risk patients (LRP, CTV = prostate) and intermediate-risk patients (IRP, CTV = prostate + seminal vesicles, SV) were included in the simulation. Two registration methods, based on center-of-mass shift of prostate only and prostate plus SV, were performed for IRP. The intensity-modulated radiotherapy was used in the simulation. Criteria on both cumulative and fractional doses were evaluated. Furthermore, the geometric evaluation was extended to investigate the optimal number of fractions necessary to construct the internal target volume (ITV) for the hybrid strategy. The dosimetric margin improvement was smaller than its geometric counterpart and was in the range of 0-1 mm. The optimal number of fractions necessary for the ITV construction is 2 for LRPs and 3-4 for IRPs in a hypofractionation protocol. A new cumulative index of target volume was proposed

  6. Dosimetric comparison between helical tomotherapy and intensity-modulated radiation therapy plans for non-small cell lung cancer

    Institute of Scientific and Technical Information of China (English)

    MENG Ling-ling; FENG Lin-chun; WANG Yun-lai; DAI Xiang-kun; XIE Chuan-bin

    2011-01-01

    Background Helical tomotherapy (HT) is a new image-guided intensity-modulated radiation therapy (IMRT) technique.It is reported that HT plan for non-small-cell lung cancer (NSCLC) can give better dose uniformity, dose gradients, and protection for the lung than IMRT plan. We compared the dosimetric characteristics of HT for NSCLC with those of conventional IMRT to observe the superiority of HT.Methods There was a comparative case series comprising 10 patients with NSCLC. Computed tomographic (CT) images of delineated targets were transferred to the PrecisePlan planning system (IMRT) and Tomo planning system (HT). The prescription doses were 70 Gy/33F for the gross tumor volume (GTV) and the visible lymph nodes (GTVnd),and 60 Gy/33F for the clinical target volume (CTV) and the clinical target volume of the visible lymph nodes (CTVnd). The dose restrictions for organs at risk were as follows: the maximum dose to spinal cord ≤45 Gy, V20 to the total lungs <30%,V50 to the heart <50%, and V55 to the esophagus <50%. Both plans were evaluated by means of the dose coverage of the targets, dose-volume histograms (DVHs), and other dosimetric indices.Results The dose coverage, conformity, and homogeneity of the targets' volumes were found to be satisfactory in both plans, but the homogeneity of the HT plan was better than that of IMRT. The high-dose radiation volume (V20-V30) to the lung and the mean lung dose (MLD) decreased (P<0.05), but the low-dose radiation volume (V5-V10) increased slightly in the HT plan (P>0.05). The maximum doses to the spinal cord, heart, esophagus and trachea in the HT plan were lower than those in the IMRT plan, but the differences were not statistically significant.Conclusions The HT plan provids better dose uniformity, dose gradients, and protectiqn for the organs at risk. It can reduce the high-dose radiation volume for lung and the MLD, but may deliver a larger lung volume of low-dose radiation.

  7. Dosimetric comparison of Acuros XB, AAA, and XVMC in stereotactic body radiotherapy for lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Tsuruta, Yusuke; Nakata, Manabu; Higashimura, Kyoji [Division of Clinical Radiology Service, Kyoto University Hospital, Kyoto 606-8507 (Japan); Nakamura, Mitsuhiro, E-mail: m-nkmr@kuhp.kyoto-u.ac.jp; Matsuo, Yukinori; Monzen, Hajime; Mizowaki, Takashi; Hiraoka, Masahiro [Department of Radiation Oncology and Image-applied Therapy, Graduate School of Medicine, Kyoto University, Kyoto 606-8507 (Japan)

    2014-08-15

    Purpose: To compare the dosimetric performance of Acuros XB (AXB), anisotropic analytical algorithm (AAA), and x-ray voxel Monte Carlo (XVMC) in heterogeneous phantoms and lung stereotactic body radiotherapy (SBRT) plans. Methods: Water- and lung-equivalent phantoms were combined to evaluate the percentage depth dose and dose profile. The radiation treatment machine Novalis (BrainLab AG, Feldkirchen, Germany) with an x-ray beam energy of 6 MV was used to calculate the doses in the composite phantom at a source-to-surface distance of 100 cm with a gantry angle of 0°. Subsequently, the clinical lung SBRT plans for the 26 consecutive patients were transferred from the iPlan (ver. 4.1; BrainLab AG) to the Eclipse treatment planning systems (ver. 11.0.3; Varian Medical Systems, Palo Alto, CA). The doses were then recalculated with AXB and AAA while maintaining the XVMC-calculated monitor units and beam arrangement. Then the dose-volumetric data obtained using the three different radiation dose calculation algorithms were compared. Results: The results from AXB and XVMC agreed with measurements within ±3.0% for the lung-equivalent phantom with a 6 × 6 cm{sup 2} field size, whereas AAA values were higher than measurements in the heterogeneous zone and near the boundary, with the greatest difference being 4.1%. AXB and XVMC agreed well with measurements in terms of the profile shape at the boundary of the heterogeneous zone. For the lung SBRT plans, AXB yielded lower values than XVMC in terms of the maximum doses of ITV and PTV; however, the differences were within ±3.0%. In addition to the dose-volumetric data, the dose distribution analysis showed that AXB yielded dose distribution calculations that were closer to those with XVMC than did AAA. Means ± standard deviation of the computation time was 221.6 ± 53.1 s (range, 124–358 s), 66.1 ± 16.0 s (range, 42–94 s), and 6.7 ± 1.1 s (range, 5–9 s) for XVMC, AXB, and AAA, respectively. Conclusions: In the

  8. Dosimetric Advantages of Midventilation Compared With Internal Target Volume for Radiation Therapy of Pancreatic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lens, Eelco, E-mail: e.lens@amc.uva.nl; Horst, Astrid van der; Versteijne, Eva; Tienhoven, Geertjan van; Bel, Arjan

    2015-07-01

    Purpose: The midventilation (midV) approach can be used to take respiratory-induced pancreatic tumor motion into account during radiation therapy. In this study, the dosimetric consequences for organs at risk and tumor coverage of using a midV approach compared with using an internal target volume (ITV) were investigated. Methods and Materials: For each of the 18 patients, 2 treatment plans (25 × 2.0 Gy) were created, 1 using an ITV and 1 using a midV approach. The midV dose distribution was blurred using the respiratory-induced motion from 4-dimensional computed tomography. The resulting planning target volume (PTV) coverage for this blurred dose distribution was analyzed; PTV coverage was required to be at least V{sub 95%} >98%. In addition, the change in PTV size and the changes in V{sub 10Gy}, V{sub 20Gy}, V{sub 30Gy}, V{sub 40Gy}, D{sub mean} and D{sub 2cc} for the stomach and for the duodenum were analyzed; differences were tested for significance using the Wilcoxon signed-rank test. Results: Using a midV approach resulted in sufficient target coverage. A highly significant PTV size reduction of 13.9% (P<.001) was observed. Also, all dose parameters for the stomach and duodenum, except the D{sub 2cc} of the duodenum, improved significantly (P≤.002). Conclusions: By using the midV approach to account for respiratory-induced tumor motion, a significant PTV reduction and significant dose reductions to the stomach and to the duodenum can be achieved when irradiating pancreatic tumors.

  9. Dosimetric comparison of axilla and groin radiotherapy techniques for high-risk and locally advanced skin cancer

    Energy Technology Data Exchange (ETDEWEB)

    Mattes, Malcolm D.; Zhou, Ying; Berry, Sean L.; Barker, Christopher A. [Memorial Sloan Kettering Cancer Center, New York (United States)

    2016-06-15

    Radiation therapy targeting axilla and groin lymph nodes improves regional disease control in locally advanced and high-risk skin cancers. However, trials generally used conventional two-dimensional radiotherapy (2D-RT), contributing towards relatively high rates of side effects from treatment. The goal of this study is to determine if three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or volumetric-modulated arc therapy (VMAT) may improve radiation delivery to the target while avoiding organs at risk in the clinical context of skin cancer regional nodal irradiation. Twenty patients with locally advanced/high-risk skin cancers underwent computed tomography simulation. The relevant axilla or groin planning target volumes and organs at risk were delineated using standard definitions. Paired t-tests were used to compare the mean values of several dose-volumetric parameters for each of the 4 techniques. In the axilla, the largest improvement for 3D-CRT compared to 2D-RT was for homogeneity index (13.9 vs. 54.3), at the expense of higher lung V{sub 20} (28.0% vs. 12.6%). In the groin, the largest improvements for 3D-CRT compared to 2D-RT were for anorectum D{sub max} (13.6 vs. 38.9 Gy), bowel D{sub 200cc} (7.3 vs. 23.1 Gy), femur D{sub 50} (34.6 vs. 57.2 Gy), and genitalia D{sub max} (37.6 vs. 51.1 Gy). IMRT had further improvements compared to 3D-CRT for humerus D{sub mean} (16.9 vs. 22.4 Gy), brachial plexus D{sub 5} (57.4 vs. 61.3 Gy), bladder D{sub 5} (26.8 vs. 36.5 Gy), and femur D{sub 50} (18.7 vs. 34.6 Gy). Fewer differences were observed between IMRT and VMAT. Compared to 2D-RT and 3D-CRT, IMRT and VMAT had dosimetric advantages in the treatment of nodal regions of skin cancer patients.

  10. A Dosimetric Comparison between Conventional Fractionated and Hypofractionated Image-guided Radiation Therapies for Localized Prostate Cancer

    Science.gov (United States)

    Li, Ming; Li, Gao-Feng; Hou, Xiu-Yu; Gao, Hong; Xu, Yong-Gang; Zhao, Ting

    2016-01-01

    Background: Image-guided radiation therapy (IGRT) is the preferred method for curative treatment of localized prostate cancer, which could improve disease outcome and reduce normal tissue toxicity reaction. IGRT using cone-beam computed tomography (CBCT) in combination with volumetric-modulated arc therapy (VMAT) potentially allows smaller treatment margins and dose escalation to the prostate. The aim of this study was to compare the difference of dosimetric diffusion in conventional IGRT using 7-field, step-and-shoot intensity-modulated radiation therapy (IMRT) and hypofractionated IGRT using VMAT for patients with localized prostate cancer. Methods: We studied 24 patients who received 78 Gy in 39 daily fractions or 70 Gy in 28 daily fractions to their prostate with/without the seminal vesicles using IMRT (n = 12) or VMAT (n = 12) for prostate cancer between November 2013 and October 2015. Image guidance was performed using kilovoltage CBCT scans equipped on the linear accelerator. Offline planning was performed using the daily treatment images registered with simulation computed tomography (CT) images. A total of 212 IMRT plans in conventional cohort and 292 VMAT plans in hypofractionated cohort were enrolled in the study. Dose distributions were recalculated on CBCT images registered with the planning CT scanner. Results: Compared with 7-field, step-and-shoot IMRT, VMAT plans resulted in improved planning target volume (PTV) D95% (7663.17 ± 69.57 cGy vs. 7789.17 ± 131.76 cGy, P V50 (P statistically significantly reduce the rectal V50, compared with 7-field, step-and-shoot IMRT (25.02 ± 5.54% vs. 27.43 ± 8.79%, P = 0.087). Conclusions: To deliver the hypofractionated radiotherapy in prostate cancer, VMAT significantly increased PTV D95% dose and decreased the dose of radiation delivered to adjacent normal tissues comparing to 7-field, step-and-shoot IMRT. Daily online image-guidance and better management of bladder and rectum could make a more precise

  11. A Dosimetric Comparison between Conventional Fractionated and Hypofractionated Image-guided Radiation Therapies for Localized Prostate Cancer

    Institute of Scientific and Technical Information of China (English)

    Ming Li; Gao-Feng Li; Xiu-Yu Hou; Hong Gao; Yong-Gang Xu; Ting Zhao

    2016-01-01

    Background:Image-guided radiation therapy (IGRT) is the preferred method for curative treatment of localized prostate cancer,which could improve disease outcome and reduce normal tissue toxicity reaction.IGRT using cone-beam computed tomography (CBCT) in combination with volumetric-modulated arc therapy (VMAT) potentially allows smaller treatment margins and dose escalation to the prostate.The aim of this study was to compare the difference of dosimetric diffusion in conventional IGRT using 7-field,step-and-shoot intensity-modulated radiation therapy (IMRT) and hypofractionated IGRT using VMAT for patients with localized prostate cancer.Methods:We studied 24 patients who received 78 Gy in 39 daily fractions or 70 Gy in 28 daily fractions to their prostate with/without the seminal vesicles using IMRT (n =12) or VMAT (n =12) for prostate cancer between November 2013 and October 2015.Image guidance was performed using kilovoltage CBCT scans equipped on the linear accelerator.Offline planning was performed using the daily treatment images registered with simulation computed tomography (CT) images.A total of 212 IMRT plans in conventional cohort and 292 VMAT plans in hypofractionated cohort were enrolled in the study.Dose distributions were recalculated on CBCT images registered with the planning CT scanner.Results:Compared with 7-field,step-and-shoot IMRT,VMAT plans resulted in improved planning target volume (PTV) D95% (7663.17 ± 69.57 cGy vs.7789.17 ± 131.76 cGy,P < 0.001).VMAT reduced the rectal D25 (P < 0.001),D35 (P < 0.001),and D50 (P < 0.001),bladder V50 (P < 0.001),D25 (P =0.002),D35 (P =0.028),and D50 (P =0.029).However,VMAT did not statistically significantly reduce the rectal V50,compared with 7-field,step-and-shoot IMRT (25.02 ± 5.54% vs.27.43 ± 8.79%,P =0.087).Conclusions:To deliver the hypofractionated radiotherapy in prostate cancer,VMAT significantly increased PTV D95% dose and decreased the dose of radiation delivered to adjacent

  12. SU-E-T-292: Dosimetric Advantage of Prone Breast Radiotherapy for Korean Left-Sided Breast Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y; Shin, J; Yu, J; Park, W; Choi, D; Huh, S; Han, Y; Kim, J [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: To evaluate the dosimetric benefit of prone breast radiotherapy for Korean left-sided early-stage breast cancer patients who have relatively small breast Methods: From April to June, 2014, 10 left-sided breast cancer patients received the whole breast irradiation in prone position after partial mastectomy with sentinel lymph node biopsy or axillary lymph node dissection. All patients were pTmi-2N0-1mi. Each patient underwent two computed tomoradiography (CT) simulations in supine and prone positions. The whole breast, ipsilateral lung, heart, and left anterior descending coronary artery (LAD) were contoured on each simulation CT images, and then tangential-fields treatment plan in each position was designed for the whole breast irradiation with the total dose of 50 Gy in 2 Gy fractions. Dose-volume histograms of two setups were compared for target coverage and radiation dose to normal organs with Wilcoxon signed rank tests. Results: The median age of patients was 47 years (range, 37 to 53). The median chest size was 82.5 cm (range, 75 to 90) and bra cup size was A in 4, B in 4, and C in 2 patients. The radiation dose to the whole breast was similar when comparing mean dose (Dmean) and dose covering 95% of the breast volume, but maximum dose (Dmax) of breast was higher in supine (median 52.3 vs. 52.7 Gy, p=0.013). Prone position reduced significantly the radiation dose in ipsilateral lung, heart, and LAD by median 5.7, 1.1, and 6.9 Gy of Dmean (p=0.005, 0.007, and 0.005) and 28.2, 18.8, and 35.0 Gy of Dmax (p=0.005, 0.005, and 0.007), respectively. Conclusion: Prone breast radiotherapy could be beneficial for Korean breast cancer patients since it substantially spared normal organs while achieving adequate coverage of the breast tissue. Further prospective study is required to validate the potential benefit of prone breast radiotherapy.

  13. SU-E-P-14: Dosimetric Effects of Magnetic Field in MRI-Guided Radiation Therapy Delivery for Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chen, G; Currey, A; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)

    2015-06-15

    Purpose: MRI-guided radiation therapy (RT) delivery would be beneficial for breast irradiation. The electron return effect due to the presence of a transverse magnetic field (TMF) may cause dosimetric issues on dose on skin and at the lung-tissue interface. The purpose of this study is to investigate these issues. Methods: IMRT plans with tangential beams and VMAT plans with 200 degree arcs to cover ipsilateral breast were generated for 10 randomly selected breast cancer cases using a research planning system (Monaco, Elekta) utilizing Monte Carlo dose calculation with or without a TMF of 1.5 T. Plans were optimized to deliver uniform dose to the whole breast with an exclusion of 5 mm tissue under the skin (PTV-EVAL). All four plans for each patient were re-scaled to have the same PTV-EVAL volume to receive the same prescription dose. The skin is defined as the first 5 mm of ipsilateral-breast tissue, plus extensions in the surrounding region. Results: The presence of 1.5 T TMF resulted in (1)increased skin dose, with the mean and maximum skin dose increase of 5% and 9%, respectively; (2) similar dose homogeneity within the PTV-EVAL; (3) the slightly improved (3%) dose homogeneity in the whole breast; (4) Averages of 9 and 16% increases in V5 and V20, respectively, for ipsilateral lung; and (5) increased the mean heart dose by 34%. VMAT plans don’t improve whole breast dose uniformity as compared that to the tangential plans. Conclusion: The presence of transverse magnetic field in MRI-guided RT delivery for whole breast irradiation can Result in slightly improved dose homogeneity in the whole breast, increased dose to the ipsilateral lung, heart, and skin. Plan optimization with additional specific dose volume constraints may eliminate/reduce these dose increases. This work is partially supported by Elekta Inc.

  14. Comparing the dosimetric impact of interfractional anatomical changes in photon, proton and carbon ion radiotherapy for pancreatic cancer patients

    Science.gov (United States)

    Houweling, Antonetta C.; Crama, Koen; Visser, Jorrit; Fukata, Kyohei; Rasch, Coen R. N.; Ohno, Tatsuya; Bel, Arjan; van der Horst, Astrid

    2017-04-01

    Radiotherapy using charged particles is characterized by a low dose to the surrounding healthy organs, while delivering a high dose to the tumor. However, interfractional anatomical changes can greatly affect the robustness of particle therapy. Therefore, we compared the dosimetric impact of interfractional anatomical changes (i.e. body contour differences and gastrointestinal gas volume changes) in photon, proton and carbon ion therapy for pancreatic cancer patients. In this retrospective planning study, photon, proton and carbon ion treatment plans were created for 9 patients. Fraction dose calculations were performed using daily cone-beam CT (CBCT) images. To this end, the planning CT was deformably registered to each CBCT; gastrointestinal gas volumes were delineated on the CBCTs and copied to the deformed CT. Fraction doses were accumulated rigidly. To compare planned and accumulated dose, dose-volume histogram (DVH) parameters of the planned and accumulated dose of the different radiotherapy modalities were determined for the internal gross tumor volume, internal clinical target volume (iCTV) and organs-at-risk (OARs; duodenum, stomach, kidneys, liver and spinal cord). Photon plans were highly robust against interfractional anatomical changes. The difference between the planned and accumulated DVH parameters for the photon plans was less than 0.5% for the target and OARs. In both proton and carbon ion therapy, however, coverage of the iCTV was considerably reduced for the accumulated dose compared with the planned dose. The near-minimum dose ({{D}98 % } ) of the iCTV reduced with 8% for proton therapy and with 10% for carbon ion therapy. The DVH parameters of the OARs differed less than 3% for both particle modalities. Fractionated radiotherapy using photons is highly robust against interfractional anatomical changes. In proton and carbon ion therapy, such changes can severely reduce the dose coverage of the target.

  15. SU-E-T-618: Dosimetric Comparison of Manual and Beam Angle Optimization of Gantry Angles in IMRT for Cervical Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lin, X; Sun, T; Liu, T; Zhang, G; Yin, Y [Shandong Cancer Hospital, Jinan, Shandong (China)

    2014-06-01

    Purpose: To evaluate the dosimetric characteristics of intensity-modulated radiotherapy (IMRT) treatment plan with beam angle optimization. Methods: Ten post-operation patients with cervical cancer were included in this analysis. Two IMRT plans using seven beams were designed in each patient. A standard coplanar equi-space beam angles were used in the first plan (plan 1), whereas the selection of beam angle was optimized by beam angle optimization algorithm in Varian Eclipse treatment planning system for the same number of beams in the second plan (plan 2). Two plans were designed for each patient with the same dose-volume constraints and prescription dose. All plans were normalized to the mean dose to PTV. The dose distribution in the target, the dose to the organs at risk and total MU were compared. Results: For conformity and homogeneity in PTV, no statistically differences were observed in the two plans. For the mean dose in bladder, plan 2 were significantly lower than plan 1(p<0.05). No statistically significant differences were observed between two plans for the mean doses in rectum, left and right femur heads. Compared with plan1, the average monitor units reduced 16% in plan 2. Conclusion: The IMRT plan based on beam angle optimization for cervical cancer could reduce the dose delivered to bladder and also reduce MU. Therefore there were some dosimetric advantages in the IMRT plan with beam angle optimization for cervical cancer.

  16. Dosimetric evaluation of neutron capture therapy for local advanced breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yanagie, H. [Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, Tokyo (Japan); Cooperative Unit of Medicine and Engineering, University of Tokyo Hospital, Tokyo (Japan)], E-mail: yanagie@n.t.u-tokyo.ac.jp; Kumada, H. [Japan Atomic Research Institute, Ibaraki (Japan); Sakurai, Y. [Research Reactor Institute, Kyoto University, Osaka (Japan); Nakamura, T. [Japan Atomic Research Institute, Ibaraki (Japan); Department of Nuclear Physics, Ibaraki University, Ibaraki (Japan); Furuya, Y. [Department of Surgery, Satukidai Hospital, Chiba (Japan); Sugiyama, H. [Cooperative Unit of Medicine and Engineering, University of Tokyo Hospital, Tokyo (Japan); Ono, K. [Research Reactor Institute, Kyoto University, Osaka (Japan); Takamoto, S. [Cooperative Unit of Medicine and Engineering, University of Tokyo Hospital, Tokyo (Japan); Department of Cardiac Surgery, University of Tokyo Hospital, Tokyo (Japan); Eriguchi, M. [Cooperative Unit of Medicine and Engineering, University of Tokyo Hospital, Tokyo (Japan); Department of Microbiology, Syowa University School of Pharmaceutical Sciences, Tokyo (Japan); Takahashi, H. [Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, Tokyo (Japan); Cooperative Unit of Medicine and Engineering, University of Tokyo Hospital, Tokyo (Japan)

    2009-07-15

    Local recurrence breast cancer is one of the most difficult conditions to cure and there is a need for new therapy. If sufficient boron compound can be targeted to the tumor, boron neutron capture therapy (BNCT) can be applied to local recurrent breast cancer. In this study, we performed a preliminary dosimetry with a phantom model of the mammary gland at Kyoto University Research Reactor (KUR), and a feasibility dosimetry with JAERI Computational Dosimetry System (JCDS) at JRR4 reactor of Japan Atomic Research Institute. We performed preliminary dosimetry of a phantom model of the mammary gland with thermal neutron irradiation (OO-0011 mode) on LiF collimation at KUR. The thermal neutron flux was 5.16 E+08 cm{sup -2} s{sup -1} at the surface of phantom. The blood boron concentration is estimated to be 30 ppm; tumor boron concentration is also estimated to be 90 ppm according to tumor/blood ratio 3 and skin/blood ratio 1.2. Tumor RBE dose is estimated to be 47 Gy/h, and skin RBE dose is 12.4 Gy/h. In case of advanced breast cancer, we performed the feasibility estimation of 3D construction of tumor according to the MRI imaging of a patient with epithermal neutron mode at JRR4. The blood boron concentration (ppm) and tumor/normal tissue ratio are estimated to be 24 and 3.5, respectively. Skin RBE dose is restricted to 10 Gy/h, the maximum tumor RBE dose, minimum tumor RBE dose, and mean tumor RBE dose are 42.2, 11.3, and 28.9 Gy-Eq, respectively, in half hour irradiation. In this study, we showed the possibility to apply BNCT to local recurrent breast cancer. We can irradiate tumors selectively and as safely as possible, reducing the effects on neighboring healthy tissues.

  17. Dosimetric comparison between coplanar and non coplanar field radiotherapy for ethmoid sinus cancer

    Directory of Open Access Journals (Sweden)

    Serre Antoine

    2007-09-01

    Full Text Available Abstract Background To compare non coplanar field (NCF with coplanar field (CF -intensity-modulated radiotherapy (IMRT planning for ethmoid cancer. Methods Seven patients treated with NCF IMRT for ethmoid cancer were studied. A CF IMRT optimization was prepared with the same constraints as for the NCF treatment. The maximum point doses (D max obtained for the different optic pathway structures (OPS should differ no more than 3% from those achieved with the NCF IMRT plan. The distribution of the dose in the target volume and in the critical structures was compared between the two techniques, as well as the Conformity (CI and the Homogeneity Indexes (HI in the target volume. Results We noted no difference between the two techniques in the OPS for the D1, D2, and D5%, in the inner ear and controlateral lens for the average Dmax, in the temporo-mandibular joints for the average mean dose, in the cord and brainstem for the average D1%. The dose-volume histograms were slightly better with the NCF treatment plan for the planning target volume (PTV with a marginally better HI but no impact on CI. We found a great improvement in the PTV coverage with the CF treatment plan for two patients with T4 tumors. Conclusion IMRT is one of the treatment options for ethmoid cancer. The PTV coverage is optimal without compromising the protection of the OPS. The impact of non coplanar versus coplanar set up is very slight.

  18. A feasibility dosimetric study on prostate cancer. Are we ready for a multicenter clinical trial on SBRT?

    Energy Technology Data Exchange (ETDEWEB)

    Marino, Carmelo; Bonanno, Elisa [Humanitas C.C.O., Catania (Italy); Villaggi, Elena [AUSL, Piacenza (Italy); Maggi, Giulia; Mancosu, Pietro [IRCCS Humanitas Clinical Research Center, Milan (Italy); Esposito, Marco [Azienda Sanitaria Firenze (Italy); Strigari, Lidia [Regina Elena National Cancer Institute, Rome (Italy). Lab. of Medical Physics and Expert Systems; Borzi, Giusi R. [REM Radioterapia, Catania (Italy); Carbonini, Claudia [A.O. Ospedale Niguarda Ca' Granda, Milan (Italy); Consorti, Rita [ACO S. Filippo Neri, Rome (Italy); Fedele, David [Casa di Cura Privata San Rossore s.r.l., Pisa (Italy); Fiandra, Christian [Torino Univ. (Italy). Radiation Oncology Unit; Ielo, Isidora [A.O.U. Policlinico G. Martino, Messina (Italy); Malatesta, Tiziana [' ' S. Giovanni Calibita' ' Fatebenefratelli, Rome (Italy); Malisan, Maria Rosa [Azienda Ospedaliero-Universitaria di Udine (Italy); Martinotti, Anna [Centro Diagnostico Italiano, Milan (Italy); Moretti, Renzo [Az. Ospedaliera Spedali Civili di Brescia (Italy); Nardiello, Barbara [UPMC San Pietro FBF, Rome (Italy); Oliviero, Caterina; Clemente, Stefania [IRCCS CROB Rieonero in Vulture, Potenza (Italy)

    2015-07-15

    The Italian Association of Medical Physics (AIFM) started a working group dedicated to stereotactic body radiotherapy (SBRT) treatment. In this work, we performed a multicenter planning study on patients who were candidates for SBRT in the treatment of prostate cancer with the aim of evaluating the dosimetric consistency among the different hospitals. Fourteen centers were provided the contours of 5 patients. Plans were performed following the dose prescription and constraints for organs at risk (OARs) of a reference paper. The dose prescription was 35 Gy in five fractions for the planning target volume (PTV). Different techniques were used (3D-CRT, fixed-Field IMRT, VMAT, CyberKnife). Plans were compared in terms of dose-volume histogram (DVH) parameters. Furthermore, the median DVH was calculated and one patient was re-planned. A total of 70 plans were compared. The maximum dose to the body was 107.9 ± 4.5 % (range 101.5-116.3 %). Dose at 98 % (D{sub 98} {sub %}) and mean dose to the clinical target volume (CTV) were 102.0 ± 0.9 % (global range 101.1-102.9 %) and 105.1 ± 0.6 % (range 98.6-124.6 %). Similar trends were found for D{sub 95} {sub %} and mean dose to the PTV. Important differences were found in terms of the homogeneity index. Doses to OARs were heterogeneous. The subgroups with the same treatment planning system showed differences comparable to the differences of the whole group. In the re-optimized plans, DVH differences among institutes were reduced and OAR sparing improved. Important dosimetric differences with possible clinical implications, in particular related to OARs, were found. Replanning allowed a reduction in the OAR dose and decreased standard deviations. Multicenter clinical trials on SBRT should require a preplanning study to standardize the optimization procedure. (orig.) [German] Der italienische Verband der Medizinphysiker (AIFM) hat eine Arbeitsgruppe gegruendet, die sich mit der Koerperstammstereotaxie (SBRT) befasst. Im Rahmen

  19. SU-E-T-332: Dosimetric Impact of Photon Energy and Treatment Technique When Knowledge Based Auto-Planning Is Implemented in Radiotherapy of Localized Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Z; Kennedy, A [Sarah Cannon, Nashville, TN (United States); Larsen, E; Grow, A; Hayes, C; Balamucki, C [North Florida Cancer Center, Gainesville, FL (United States); Salmon, H; Thompson, M [Lake City Cancer Center, Lake City, FL (United States)

    2015-06-15

    Purpose: The aim of this study was to investigate the dosimetric impact of the combination of photon energy and treatment technique on radiotherapy of localized prostate cancer when knowledge based planning was used. Methods: A total of 16 patients with localized prostate cancer were retrospectively retrieved from database and used for this study. For each patient, four types of treatment plans with different combinations of photon energy (6X and 10X) and treatment techniques (7-field IMRT and 2-arc VMAT) were created using a prostate DVH estimation model in RapidPlan™ and Eclipse treatment planning system (Varian Medical System). For any beam arrangement, DVH objectives and weighting priorities were generated based on the geometric relationship between the OAR and PTV. Photon optimization algorithm was used for plan optimization and AAA algorithm was used for final dose calculation. Plans were evaluated in terms of the pre-defined dosimetric endpoints for PTV, rectum, bladder, penile bulb, and femur heads. A Student’s paired t-test was used for statistical analysis and p > 0.05 was considered statistically significant. Results: For PTV, V95 was statistically similar among all four types of plans, though the mean dose of 10X plans was higher than that of 6X plans. VMAT plans showed higher heterogeneity index than IMRT plans. No statistically significant difference in dosimetry metrics was observed for rectum, bladder, and penile bulb among plan types. For left and right femur, VMAT plans had a higher mean dose than IMRT plans regardless of photon energy, whereas the maximum dose was similar. Conclusion: Overall, the dosimetric endpoints were similar regardless of photon energy and treatment techniques when knowledge based auto planning was used. Given the similarity in dosimetry metrics of rectum, bladder, and penile bulb, the genitourinary and gastrointestinal toxicities should be comparable among the selections of photon energy and treatment techniques.

  20. Adjuvant radiotherapy for gallbladder cancer: A dosimetric comparison of conformal radiotherapy and intensity-modulated radiotherapy

    Institute of Scientific and Technical Information of China (English)

    Xiao-Nan Sun; Qi Wang; Ben-Xing Gu; Yan-Hong Zhu; Jian-Bin Hu; Guo-Zhi Shi; Shu Zheng

    2011-01-01

    AIM: To assess the efficacy and toxicity of conformal radiotherapy (CRT) and compare with intensity-modulated radiotherapy (IMRT) in the treatment of gallbladder cancer.METHODS: Between November 2003 and January 2010, 20 patients with gallbladder cancer were treated with CRT with or without chemotherapy after surgical resection. Preliminary survival data were collected and examined using both Kaplan-Meier and actuarial analysis. Demographic and treatment parameters were collected. All patients were planned to receive 46-56 Gy in 1.8 or 2.0 Gy per fraction. CRT planning was compared with IMRT.RESULTS: The most common reported acute toxicities requiring medication (Radiation Therapy Oncology Group, Radiation Therapy Oncology Group Grade2) were nausea (10/20 patients) and diarrhea (3/20).There were no treatment-related deaths. Compared with CRT planning, IMRT significantly reduced the volume of right kidney receiving > 20 Gy and the volume of liver receiving > 30 Gy. IMRT has a negligible impact on the volume of left kidney receiving > 20 Gy. The 95% of prescribed dose for a planning tumor volume using either 3D CRT or IMRT planning were 84.0% ±6.7%, 82.9% ± 6.1%, respectively (P > 0.05).CONCLUSION: IMRT achieves similar excellent target coverage as compared with CRT planning, while reducingthe mean liver dose and volume above threshold dose. IMRT offers better sparing of the right kidney compared with CRT planning, with a significantly lower mean dose and volume above threshold dose.

  1. A dosimetric comparison of proton and photon therapy in unresectable cancers of the head of pancreas

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Reid F.; Zhai, Huifang; Both, Stefan; Metz, James M.; Plastaras, John P.; Ben-Josef, Edgar, E-mail: Edgar.Ben-Josef@uphs.upenn.edu [University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Mayekar, Sonal U. [Thomas Jefferson University, Philadelphia, Pennsylvania 19107 (United States); Apisarnthanarax, Smith [University of Washington, Seattle, Washington 98109 (United States)

    2014-08-15

    Purpose: Uncontrolled local growth is the cause of death in ∼30% of patients with unresectable pancreatic cancers. The addition of standard-dose radiotherapy to gemcitabine has been shown to confer a modest survival benefit in this population. Radiation dose escalation with three-dimensional planning is not feasible, but high-dose intensity-modulated radiation therapy (IMRT) has been shown to improve local control. Still, dose-escalation remains limited by gastrointestinal toxicity. In this study, the authors investigate the potential use of double scattering (DS) and pencil beam scanning (PBS) proton therapy in limiting dose to critical organs at risk. Methods: The authors compared DS, PBS, and IMRT plans in 13 patients with unresectable cancer of the pancreatic head, paying particular attention to duodenum, small intestine, stomach, liver, kidney, and cord constraints in addition to target volume coverage. All plans were calculated to 5500 cGy in 25 fractions with equivalent constraints and normalized to prescription dose. All statistics were by two-tailed paired t-test. Results: Both DS and PBS decreased stomach, duodenum, and small bowel dose in low-dose regions compared to IMRT (p < 0.01). However, protons yielded increased doses in the mid to high dose regions (e.g., 23.6–53.8 and 34.9–52.4 Gy for duodenum using DS and PBS, respectively; p < 0.05). Protons also increased generalized equivalent uniform dose to duodenum and stomach, however these differences were small (<5% and 10%, respectively; p < 0.01). Doses to other organs-at-risk were within institutional constraints and placed no obvious limitations on treatment planning. Conclusions: Proton therapy does not appear to reduce OAR volumes receiving high dose. Protons are able to reduce the treated volume receiving low-intermediate doses, however the clinical significance of this remains to be determined in future investigations.

  2. A Dosimetric Comparison of Tomotherapy and Volumetric Modulated Arc Therapy in the Treatment of High-Risk Prostate Cancer With Pelvic Nodal Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Pasquier, David, E-mail: d-pasquier@o-lambret.fr [Departement Universitaire de Radiotherapie, Centre O. Lambret, Lille (France); Universite Lille Nord de France, Lille (France); Centre Galilee, Clinique de la Louviere, Lille (France); Cavillon, Fabrice [Universite Lille Nord de France, Lille (France); Faculte Libre de Medecine, Lille (France); Lacornerie, Thomas [Departement Universitaire de Radiotherapie, Centre O. Lambret, Lille (France); Universite Lille Nord de France, Lille (France); Touzeau, Claire [Centre Galilee, Clinique de la Louviere, Lille (France); Tresch, Emmanuelle [Unite de Methodologie et Biostatistique, Centre O. Lambret, Lille (France); Lartigau, Eric [Departement Universitaire de Radiotherapie, Centre O. Lambret, Lille (France); Universite Lille Nord de France, Lille (France)

    2013-02-01

    Purpose: To compare the dosimetric results of volumetric modulated arc therapy (VMAT) and helical tomotherapy (HT) in the treatment of high-risk prostate cancer with pelvic nodal radiation therapy. Methods and Materials: Plans were generated for 10 consecutive patients treated for high-risk prostate cancer with prophylactic whole pelvic radiation therapy (WPRT) using VMAT and HT. After WPRT, a sequential boost was delivered to the prostate. Plan quality was assessed according to the criteria of the International Commission on Radiation Units and Measurements 83 report: the near-minimal (D98%), near-maximal (D2%), and median (D50%) doses; the homogeneity index (HI); and the Dice similarity coefficient (DSC). Beam-on time, integral dose, and several organs at risk (OAR) dosimetric indexes were also compared. Results: For WPRT, HT was able to provide a higher D98% than VMAT (44.3 {+-} 0.3 Gy and 43.9 {+-} 0.5 Gy, respectively; P=.032) and a lower D2% than VMAT (47.3 {+-} 0.3 Gy and 49.1 {+-} 0.7 Gy, respectively; P=.005), leading to a better HI. The DSC was better for WPRT with HT (0.89 {+-} 0.009) than with VMAT (0.80 {+-} 0.02; P=.002). The dosimetric indexes for the prostate boost did not differ significantly. VMAT provided better rectum wall sparing at higher doses (V70, V75, D2%). Conversely, HT provided better bladder wall sparing (V50, V60, V70), except at lower doses (V20). The beam-on times for WPRT and prostate boost were shorter with VMAT than with HT (3.1 {+-} 0.1 vs 7.4 {+-} 0.6 min, respectively; P=.002, and 1.5 {+-} 0.05 vs 3.7 {+-} 0.3 min, respectively; P=.002). The integral dose was slightly lower for VMAT. Conclusion: VMAT and HT provided very similar and highly conformal plans that complied well with OAR dose-volume constraints. Although some dosimetric differences were statistically significant, they remained small. HT provided a more homogeneous dose distribution, whereas VMAT enabled a shorter delivery time.

  3. Maximizing dosimetric benefits of IMRT in the treatment of localized prostate cancer through multicriteria optimization planning

    Energy Technology Data Exchange (ETDEWEB)

    Wala, Jeremiah; Craft, David [Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Paly, Jon [Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Zietman, Anthony [Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States); Efstathiou, Jason, E-mail: jefstathiou@partners.org [Harvard Medical School, Boston, MA (United States); Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA (United States)

    2013-10-01

    We examine the quality of plans created using multicriteria optimization (MCO) treatment planning in intensity-modulated radiation therapy (IMRT) in treatment of localized prostate cancer. Nine random cases of patients receiving IMRT to the prostate were selected. Each case was associated with a clinically approved plan created using Corvus. The cases were replanned using MCO-based planning in RayStation. Dose-volume histogram data from both planning systems were presented to 2 radiation oncologists in a blinded evaluation, and were compared at a number of dose-volume points. Both physicians rated all 9 MCO plans as superior to the clinically approved plans (p<10{sup −5}). Target coverage was equivalent (p = 0.81). Maximum doses to the prostate and bladder and the V50 and V70 to the anterior rectum were reduced in all MCO plans (p<0.05). Treatment planning time with MCO took approximately 60 minutes per case. MCO-based planning for prostate IMRT is efficient and produces high-quality plans with good target homogeneity and sparing of the anterior rectum, bladder, and femoral heads, without sacrificing target coverage.

  4. Dosimetric comparison of free-breathing and deep inspiration breath-hold radiotherapy for lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Marchand, V.; Desrousseaux, J.; Dauphinot, C. [Institut Curie, Paris (France). Dept. of Radiotherapy; Zefkili, S.; Simon, L. [Institut Curie, Paris (France). Dept. of Radiophysics; Giraud, P. [Institut Curie, Paris (France). Dept. of Radiotherapy; Hopital Europeen Georges Pompidou, Paris Descartes Univ., Paris (France). Dept. of Radiotherapy

    2012-07-15

    Purpose: The goal of this work was to evaluate the feasibility and outcome of intensity-modulated arc therapy {+-} cisplatin (IMAT {+-} C) followed by hysterectomy for locally advanced cervical cancer. Patients and methods: A total of 30 patients were included in the study. The primary tumour and PET-positive lymph node(s) received a simultaneous integrated boost. Four weeks after IMAT {+-} C treatment, response was evaluated. Resection consisted of hysterectomy with or without lymphadenectomy. Tumour response, acute and late radiation toxicity, postoperative morbidity and outcome were evaluated. Results: All hysterectomy specimens were macroscopically tumour-free with negative resection margins; pathological complete response was 40%. In 2 patients, one resected lymph node was positive. There was no excess in postoperative morbidity. Apart from two grade 3 hematologic toxicities, no grade 3 or 4 acute radiation toxicity was observed. No grade 3, 1 grade 4 (4%) intestinal, and 4 grade 3 (14%) urinary late toxicities were observed. The 2-year local and regional control rates were 96% and 100%, respectively. The 2-year distant control rate was 92%. Actuarial 2-year progression free survival rate was 89%. Actuarial 1- and 2-year overall survival rates were 96% and 91%, while 3-year overall survival was 84%. Conclusion: Surgery after IMAT {+-} C is feasible with low postoperative morbidity and radiation toxicity. Local, regional, distant control and survival rates are promising. (orig.)

  5. Dosimetric comparison of flattened and unflattened beams for stereotactic ablative radiotherapy of stage I non-small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hrbacek, Jan, E-mail: jan.hrbacek@psi.ch [Klinik für Radio-Onkologie, UniversitätsSpital Zürich, 8091 Zürich, Switzerland and Center for Proton Therapy, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Lang, Stephanie; Graydon, Shaun N.; Klöck, Stephan; Riesterer, Oliver [Klinik für Radio-Onkologie, UniversitätsSpital Zürich, 8091 Zürich (Switzerland)

    2014-03-15

    Purpose: To compare contribution and accuracy of delivery for two flattening filter free (FFF) beams of the nominal energy 6 and 10 MV and a 6 MV flattened beam for early stage lung cancer. Methods: For each of 11 patients with stage I nonsmall cell lung cancer three volumetric modulated arc therapy plans were prepared utilizing a 6 MV flattened photon beam (X6FF) and two nonflattened beams of nominal energy 6 and 10 MV (X6FFF, X10FFF). Optimization constraints were set to produce dose distributions that meet the criteria of the RTOG-0915 protocol. The radiation schedule used for plan comparison in all patients was 50 Gy in five fractions. Dosimetric parameters of planning target volume (PTV) and organs-at-risk and delivery times were assessed and compared. All plans were subject to verification using Delta{sup 4} unit (Scandidos, Sweden) and absolutely calibrated gafchromic films in a thorax phantom. Results: All plans had a qualitatively comparable outcome. Obtained dose distributions were conformal (CI < 1.17) and exhibited a steep dose fall-off outside the PTV. The ratio of monitor units for FFF versus FF plans in the authors' study ranged from 0.95 to 1.21 and from 0.93 to 1.25 for X6FFF/X6FF and X10FFF/X6FF comparisons, respectively. The ratio systematically increased with increasing size of the PTV (up to +25% for 150 cm{sup 3} PTV). Yet the integral dose to healthy tissue did not follow this trend. Comparison of cumulative dose volume histograms for a patient's body showed that X6FFF plans exhibit improved conformity and reduced the volume of tissue that received more than 50% of the prescription dose. Parameters related to dose gradient showed statistically significant improvement. CI{sub 50%}, CI{sub 60%}, CI{sub 80%}, and CI{sub 100%} were on average reduced by 4.6% (p < 0.001), 4.6% (p = 0.002), 3.1% (p = 0.002), and 1.2% (p = 0.039), respectively. Gradient measure was on average reduced by 4.2% (p < 0.001). Due to dose reduction in the

  6. Dosimetric model for intraperitoneal targeted liposomal radioimmunotherapy of ovarian cancer micrometastases

    Energy Technology Data Exchange (ETDEWEB)

    Syme, A M [Department of Physics, University of Alberta, 412 Avadh Bhatia Physics Laboratory, Edmonton, Alberta T6G 2J1 (Canada); McQuarrie, S A [Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, 3118 Dentistry/Pharmacy Centre, Edmonton, Alberta T6G 2N8 (Canada); Middleton, J W [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Fallone, B G [Departments of Physics and Oncology, University of Alberta, 11560 University Avenue, Edmonton, Alberta T6G 1Z2 (Canada)

    2003-05-21

    A simple model has been developed to investigate the dosimetry of micrometastases in the peritoneal cavity during intraperitoneal targeted liposomal radioimmunotherapy. The model is applied to free-floating tumours with radii between 0.005 cm and 0.1 cm. Tumour dose is assumed to come from two sources: free liposomes in solution in the peritoneal cavity and liposomes bound to the surface of the micrometastases. It is assumed that liposomes do not penetrate beyond the surface of the tumours and that the total amount of surface antigen does not change over the course of treatment. Integrated tumour doses are expressed as a function of biological parameters that describe the rates at which liposomes bind to and unbind from the tumour surface, the rate at which liposomes escape from the peritoneal cavity and the tumour surface antigen density. Integrated doses are translated into time-dependent tumour control probabilities (TCPs). The results of the work are illustrated in the context of a therapy in which liposomes labelled with Re-188 are targeted at ovarian cancer cells that express the surface antigen CA-125. The time required to produce a TCP of 95% is used to investigate the importance of the various parameters. The relative contributions of surface-bound radioactivity and unbound radioactivity are used to assess the conditions required for a targeted approach to provide an improvement over a non-targeted approach during intraperitoneal radiation therapy. Using Re-188 as the radionuclide, the model suggests that, for microscopic tumours, the relative importance of the surface-bound radioactivity increases with tumour size. This is evidenced by the requirement for larger antigen densities on smaller tumours to affect an improvement in the time required to produce a TCP of 95%. This is because for the smallest tumours considered, the unbound radioactivity is often capable of exerting a tumouricidal effect before the targeting agent has time to accumulate

  7. Dosimetric comparison using different multileaf collimeters in intensity-modulated radiotherapy for upper thoracic esophageal cancer

    Directory of Open Access Journals (Sweden)

    Fu Yuchuan

    2010-07-01

    Full Text Available Abstract Purpose To study the impacts of multileaf collimators (MLC width [standard MLC width of 10 mm (sMLC and micro-MLC width of 4 mm (mMLC] in the intensity-modulated radiotherapy (IMRT planning for the upper thoracic esophageal cancer (UTEC. Methods and materials 10 patients with UTEC were retrospectively planned with the sMLC and the mMLC. The monitor unites (MUs and dose volume histogram-based parameters [conformity index (CI and homogeneous index (HI] were compared between the IMRT plans with sMLC and with mMLC. Results The IMRT plans with the mMLC were more efficient (average MUs: 703.1 ± 68.3 than plans with the sMLC (average MUs: 833.4 ± 73.8 (p p 5 (3260.3 ± 374.0 vs 3404.5 ± 374.4/gEUD (1815.1 ± 281.7 vs 1849.2 ± 297.6 of the spinal cord, the V10 (33.2 ± 6.5 vs 34.0 ± 6.7, V20 (16.0 ± 4.6 vs 16.6 ± 4.7, MLD (866.2 ± 174.1 vs 887.9 ± 172.1 and gEUD (938.6 ± 175.2 vs 956.8 ± 171.0 of the lungs were observed in the plans with the mMLC, respectively (p Conclusions Comparing to the sMLC, the mMLC not only demonstrated higher efficiencies and more optimal target coverage, but also considerably improved the dose sparing of OARs in the IMRT planning for UTEC.

  8. Impact of post-operative radiation on coronary arteries in patients of early breast cancer: A pilot dosimetric study from a tertiary cancer care center from India

    Directory of Open Access Journals (Sweden)

    S Roy

    2015-01-01

    Full Text Available Background: The significant impact of postoperative radiotherapy (PORT on cardiac morbidity in patients of early breast cancer (EBC undergoing breast-conserving surgery has been shown in different studies. The present study was conducted to assess the impact of surgery and the side of involvement on radiation dose to left anterior descending artery (LAD and Left circumflex coronary artery (LCx. Materials And Methods: Totally, 58 patients of EBC were randomly chosen for this dosimetric study and planned with tangential field technique without intensity modulation (IM. Heart, LAD, and LCx (n = 55 were contoured. Dose volume histograms were analyzed to determine the Dmax (maximum dose and Dmean (mean dose of LAD and LCx. Student's t-test was used for comparative analysis of the means. Results: The mean Dmax of LAD for left (L EBC was 3.17 Gray (Gy while for right (R EBC it was 0.86 Gy (P = 0.007; 95% C.I, 1.14–3.48. The mean Dmean of LAD for L-EBC and R-EBC were 1.97 Gy and 0.79 Gy, respectively (P = 0.029; 95% C.I, 0.77–1.60. The mean-Dmax of LCx for patients with L-EBC (2.9 Gy; range: 1.2–4.35 Gy was statistically higher than that for R-EBC (1.3 Gy; range: 0.7–3.2 Gy (P = 0.045. The mean-Dmean of LCx for L-EBC (2.1 Gy; range: 0.6–3.6 Gy was also significantly higher than that of L-EBC (0.9 Gy; range: 0.7–2.1 Gy (P = 0.03. There was no significant impact of the pattern of surgery on LAD dose, but significance was noted for LCx dose parameters (P = 0.04 and 0.08 for m-Dmax and m-Dmean of LCx. Conclusion: This pilot dosimetric study confirms the assumption that patients with left-sided EBC are at higher risk of developing long-term cardiac morbidity when treated with PORT due to increased dose to LAD.

  9. SU-E-T-233: Cyberknife Versus Linac IMRT for Dose Comparision in Hypofractionated Hemi Larynx Irradiation of Early Stage True Vocal Cord Cancer: A Dosimetric Study

    Energy Technology Data Exchange (ETDEWEB)

    Ding, C; Lee, P; Jiang, S [UT Southwestern Medical Center, Dallas, TX (United States)

    2015-06-15

    Purpose: To compare dosimetric data of patients treated for early-stage larynx cancer on Cyberknife and Linac IMRT. Methods: Nine patients were treated with Cyberknife to a dose of 45 Gy in 10 fractions of the involved hemilarynx. The prescription dose provided at least 95% of PTV coverage. After Cyberknife treatment, the CT images and contours were sent to Pinnacle treatment planning system for IMRT planning on a regular SBRT linac with same dose prescription and constrains. Dose to target and normal tissue, including the arytenoids, cord, carotid arteries, thyroid, and skin, were analyzed using dose volume histograms. Results: For Cyberknife plan, the conformity indices are within 1.11–1.33. The average dose to the contralateral arytenoids for Cyberknife plans was 28.9±6.5Gy), which is lower than the same mean dose for IMRT plans (34.0±5.2 Gy). The average maximum dose to the ipsilateral and contralateral carotid artery were 20.6 ±9.1 Gy and 10.2±6.0 Gy respectively for Cybeknife comparing with 22.1±8.0 Gy and 12.0±5.1 Gy for IMRT. The mean dose to the thyroid was 3.6±2.2 Gy for Cyberknife and 3.4±2.4 Gy for IMRT. As shown in DVH, the Cyberknife can deliver less dose to the normal tissue which is close to target area comparing with IMRT Plans. However, IMRT plan’s can give more sparing for the critical organs which is far away from the target area. Conclusion: We have compared the dosimetric parameters of Cyberknife and linac IMRT plans for patients with early-stage larynx cancer. Both Cyberknife and IMRT plans can achieve conformal dose distribution to the target area. Cyberknife was able to reduce normal tissue dose in high doses region while IMRT plans can reduce the dose of the normal tissue at the low dose region. These dosimetric parameters can be used to guide future prospective protocols using SBRT for larynx cancer.

  10. Comparison of dosimetric parameters and toxicity in esophageal cancer patients undergoing 3D conformal radiotherapy or VMAT

    Energy Technology Data Exchange (ETDEWEB)

    Muench, Stefan; Aichmeier, Sylvia; Duma, Marciana-Nona; Oechsner, Markus; Habermehl, Daniel [TU Muenchen, Department of Radiation Oncology, Klinikum rechts der Isar, Muenchen (Germany); Hapfelmeier, Alexander [TU Muenchen, Institute of Medical Statistics and Epidemiology (IMSE), Klinikum rechts der Isar, Muenchen (Germany); Feith, Marcus [TU Muenchen, Department of Visceral Surgery, Klinikum rechts der Isar, Muenchen (Germany); Combs, Stephanie E. [TU Muenchen, Department of Radiation Oncology, Klinikum rechts der Isar, Muenchen (Germany); Helmholtz Zentrum Muenchen, Institute of Innovative Radiotherapy (iRT), Oberschleissheim (Germany)

    2016-10-15

    Volumetric-modulated arc therapy (VMAT) achieves high conformity to the planned target volume (PTV) and good sparing of organs at risk (OAR). This study compares dosimetric parameters and toxicity in esophageal cancer (EC) patients treated with VMAT and 3D conformal radiotherapy (3D-CRT). Between 2007 and 2014, 17 SC patients received neoadjuvant chemoradiation (CRT) with VMAT. Dose-volume histograms and toxicity were compared between these patients and 20 treated with 3D-CRT. All patients were irradiated with a total dose of 45 Gy. All VMAT patients received simultaneous chemotherapy with cisplatin and 5-fluorouracil (5-FU) in treatment weeks 1 and 5. Of 20 patients treated with 3D-CRT, 13 (65 %) also received CRT with cisplatin and 5-FU, whereas 6 patients (30 %) received CRT with weekly oxaliplatin and cetuximab, and a continuous infusion of 5-FU (OE-7). There were no differences in baseline characteristics between the treatment groups. For the lungs, VMAT was associated with a higher V{sub 5} (median 90.1 % vs. 79.7 %; p = 0.013) and V{sub 10} (68.2 % vs. 56.6 %; p = 0.014), but with a lower V{sub 30} (median 6.6 % vs. 11.0 %; p = 0.030). Regarding heart parameters, VMAT was associated with a higher V{sub 5} (median 100.0 % vs. 91.0 %; p = 0.043), V{sub 10} (92.0 % vs. 79.2 %; p = 0.047), and D{sub max} (47.5 Gy vs. 46.3 Gy; p = 0.003), but with a lower median dose (18.7 Gy vs. 30.0 Gy; p = 0.026) and V{sub 30} (17.7 % vs. 50.4 %; p = 0.015). Complete resection was achieved in 16 VMAT and 19 3D-CRT patients. Due to systemic progression, 2 patients did not undergo surgery. The most frequent postoperative complication was anastomosis insufficiency, occurring in 1 VMAT (6.7 %) and 5 3D-CRT patients (27.8 %; p = 0.180). Postoperative pneumonia was seen in 2 patients of each group (p = 1.000). There was no significant difference in 3-year overall (65 % VMAT vs. 45 % 3D-CRT; p = 0.493) or 3-year progression-free survival (53 % VMAT vs. 35 % 3D-CRT; p = 0

  11. Analysis of Dosimetric Parameters Associated With Acute Gastrointestinal Toxicity and Upper Gastrointestinal Bleeding in Locally Advanced Pancreatic Cancer Patients Treated With Gemcitabine-Based Concurrent Chemoradiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Akira [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto (Japan); Shibuya, Keiko, E-mail: kei@kuhp.kyoto-u.ac.jp [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto (Japan); Matsuo, Yukinori; Nakamura, Mitsuhiro; Shiinoki, Takehiro; Mizowaki, Takashi; Hiraoka, Masahiro [Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto (Japan)

    2012-10-01

    Purpose: To identify the dosimetric parameters associated with gastrointestinal (GI) toxicity in patients with locally advanced pancreatic cancer (LAPC) treated with gemcitabine-based chemoradiotherapy. Methods and Materials: The data from 40 patients were analyzed retrospectively. Chemoradiotherapy consisted of conventional fractionated three-dimensional radiotherapy and weekly gemcitabine. Treatment-related acute GI toxicity and upper GI bleeding (UGB) were graded according to the Common Toxicity Criteria Adverse Events, version 4.0. The dosimetric parameters (mean dose, maximal absolute dose which covers 2 cm{sup 3} of the organ, and absolute volume receiving 10-50 Gy [V{sub 10-50}]) of the stomach, duodenum, small intestine, and a composite structure of the stomach and duodenum (StoDuo) were obtained. The planning target volume was also obtained. Univariate analyses were performed to identify the predictive factors for the risk of grade 2 or greater acute GI toxicity and grade 3 or greater UGB, respectively. Results: The median follow-up period was 15.7 months (range, 4-37). The actual incidence of acute GI toxicity was 33%. The estimated incidence of UGB at 1 year was 20%. Regarding acute GI toxicity, a V{sub 50} of {>=}16 cm{sup 3} of the stomach was the best predictor, and the actual incidence in patients with V{sub 50} <16 cm{sup 3} of the stomach vs. those with V{sub 50} of {>=}16 cm{sup 3} was 9% vs. 61%, respectively (p = 0.001). Regarding UGB, V{sub 50} of {>=}33 cm{sup 3} of the StoDuo was the best predictor, and the estimated incidence at 1 year in patients with V{sub 50} <33 cm{sup 3} of the StoDuo vs. those with V{sub 50} {>=}33 cm{sup 3} was 0% vs. 44%, respectively (p = 0.002). The dosimetric parameters correlated highly with one another. Conclusion: The irradiated absolute volume of the stomach and duodenum are important for the risk of acute GI toxicity and UGB. These results could be helpful in escalating the radiation doses using novel

  12. SU-E-T-25: A Dosimetric Comparison of Three-Dimension Conformal and Intensity-Modulated Radiation Therapy in Esophageal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, N; Maneru, F; Fuentemilla, N; Olasolo, J; Gracia, M; Pellejero, S; Bragado, L; Lozares, S; Miquelez, S; Martin, M [Complejo Hospitalario de Navarra, Pamplona, Navarra (Spain)

    2015-06-15

    Purpose: dosimetric comparison of 3DCRT and IMRT in 9 esophageal cancer. The aim of this paper is to know which of these two techniques is dosimetrically more favorable dosimetrically at both the CTV coverage and dose obtained in the relevant organs at risk, in this case, lungs and heart, as the spinal cord received in all cases below 45 Gy. Methods: we chose 9 patients from our center (CHN) with the same type of esophageal cancer and in which the prescribed dose was the same, 54 Gy. For these treatments we have used the same fields and the same angles (AP (0 °), OPD (225°–240°) and OPI (125°–135°)).All plans have been implemented using Eclipse (version 11.0) with AAA( Analytical Anisotropic Algorithm )(Version 11.0.31). Results: To analyze the coverage of the CTV, we have evaluated the D99% and found that the average dose received by 99% of CTV with IMRT is 53.8 ± 0.4 Gy (99.6% of the prescribed dose) and the mean value obtained with 3DCRT is 52.3 ± 0.6 Gy (96.8% of the prescribed dose).The last data analyzed was the D2% of PTV, a fact that gives us information on the maximum dose received by our PTV. D2% of the PTV for IMRT planning is 55.4 ± 0.4 Gy (102.6% of the prescribed dose) and with 3DCRT is 56.8 ± 0.7 Gy (105.2% of the prescribed dose).All parameters analyzed at risk organs (V30, V40, V45 and V50 for the case of heart and V5, V10, V15 and V20 for the case of the lungs) provide us irradiated volume percentages lower in IMRT than 3DCRT. Conclusion: IMRT provides a considerable improvement in the coverage of the CTV and the doses to organs at risk.

  13. TU-F-17A-06: Motion Stability and Dosimetric Impact of Spirometer-Based DIBH-RT of Left-Sided Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    McKenzie, E; Yang, W; Burnison, M; Mirhadi, A; Hakimian, B; Stephen, S; Robert, R; Yue, Y; Sandler, H; Fraass, B [Cedars-Sinai Medical Center, Los Angeles, CA (United States)

    2014-06-15

    Purpose: Patients undergoing radiotherapy (RT) for left-sided breast cancer have increased risk of coronary artery disease. Deep Inhalation Breath Hold assisted RT (DIBH-RT) is shown to increase the geometric separation of the target area and heart, reducing cardiac radiation dose. The purposes of this study are to use Cine MV portal images to determine the stability of spirometer-guided DIBH-RT and examine the dosimetric cardiopulmonary impact of this technique. Methods: Twenty consecutive patients with left-sided breast cancer were recruited to the IRB-approved study. Free-breathing (FB) and DIBH-CT's were acquired at simulation. Rigid registration of the FB-CT and DIBH-CT was performed using primarily breast tissue. Treatment plans were created for each FB-CT and DIBH-CT using identical paired tangent fields with field-in-field or electronic compensation techniques. Dosimetric evaluation included mean and maximum (Dmax) doses for the left anterior descending artery (LAD), mean heart dose, and left lung V20. Cine MV portal images were acquired for medial and lateral fields during treatment. Analysis of Cine images involved chest wall segmentation using an algorithm developed in-house. Intra- and inter-fractional chest wall motion were determined through affine registration to the first frame of each Cine. Results: Dose to each cardiac structure evaluated was significantly (p<0.001) reduced with the DIBH plans. Mean heart dose decreased from 2.9(0.9–6.6) to 1.6(0.6–5.3) Gy; mean LAD dose from 16.6(3–43.6) to 7.4(1.7–32.7) Gy; and LAD Dmax from 35.4 (6.1–53) to 18.4(2.5–51.2) Gy. No statistically significant reduction was found for the left lung V20. Average AP and SI median chest wall motion (intrafractional) was 0.1 (SD=0.9) and 0.5 (SD=1.1) mm, respectively. Average AP inter-fractional chest wall motion was 2.0 (SD=1.4) mm. Conclusion: Spirometer-based DIBH treatments of the left breast are reproducible both inter- and intra-fractionally, and

  14. SU-E-J-170: Dosimetric Consequences of Uncorrected Rotational Setup Errors During Stereotactic Body Radiation Therapy (SBRT) Treatment of Pancreatic Cancers

    Energy Technology Data Exchange (ETDEWEB)

    Di Maso, L [Chicago, IL (United States); Forbang, R Teboh; Zhang, Y; Herman, J; Lee, J [John Hopkins University, Baltimore, MD (United States)

    2015-06-15

    Purpose: To explore the dosimetric consequences of uncorrected rotational setup errors during SBRT for pancreatic cancer patients. Methods: This was a retrospective study utilizing data from ten (n=10) previously treated SBRT pancreas patients. For each original planning CT, we applied rotational transformations to derive additional CT images representative of possible rotational setup errors. This resulted in 6 different sets of rotational combinations, creating a total of 60 CT planning images. The patients’ clinical dosimetric plans were then applied to their corresponding rotated CT images. The 6 rotation sets encompassed a 3, 2 and 1-degree rotation in each rotational direction and a 3-degree in just the pitch, a 3-degree in just the yaw and a 3-degree in just the roll. After the dosimetric plan was applied to the rotated CT images, the resulting plan was then evaluated and compared with the clinical plan for tumor coverage and normal tissue sparing. Results: PTV coverage, defined here by V33 throughout all of the patients’ clinical plans, ranged from 92–98%. After an n degree rotation in each rotational direction that range decreased to 68–87%, 85–92%, and 88– 94% for n=3, 2 and 1 respectively. Normal tissue sparing defined here by the proximal stomach V15 throughout all of the patients’ clinical plans ranged from 0–8.9 cc. After an n degree rotation in each rotational direction that range increased to 0–17 cc, 0–12 cc, and 0–10 cc for n=3, 2, and 1 respectively. Conclusion: For pancreatic SBRT, small rotational setup errors in the pitch, yaw and roll direction on average caused under dosage to PTV and over dosage to proximal normal tissue. The 1-degree rotation was on average the least detrimental to the normal tissue and the coverage of the PTV. The 3-degree yaw created on average the lowest increase in volume coverage to normal tissue. This research was sponsored by the AAPM Education Council through the AAPM Education and Research

  15. SU-E-J-21: Setup Variability of Colorectal Cancer Patients Treated in the Prone Position and Dosimetric Comparison with the Supine Position

    Energy Technology Data Exchange (ETDEWEB)

    Kim, A; Foster, J; Chu, W; Karotki, A [Sunnybrook Health Sciences Centre/Odette Cancer Centre, Toronto, Ontario (Canada)

    2015-06-15

    Purpose: Many cancer centers treat colorectal patients in the prone position on a belly board to minimize dose to the small bowel. That may potentially Result in patient setup instability with corresponding impact on dose delivery accuracy for highly conformal techniques such as IMRT/VMAT. Two aims of this work are 1) to investigate setup accuracy of rectum patients treated in the prone position on a belly board using CBCT and 2) to evaluate dosimetric impact on bladder and small bowel of treating rectum patients in supine vs. prone position. Methods: For the setup accuracy study, 10 patients were selected. Weekly CBCTs were acquired and matched to bone. The CBCT-determined shifts were recorded. For the dosimetric study, 7 prone-setup patients and 7 supine-setup patients were randomly selected from our clinical database. Various clinically relevant dose volume histogram values were recorded for the small bowel and bladder. Results: The CBCT-determined rotational shifts had a wide variation. For the dataset acquired at the time of this writing, the ranges of rotational setup errors for pitch, roll, and yaw were [−3.6° 4.7°], [−4.3° 3.2°], and [−1.4° 1.4°]. For the dosimetric study: the small bowel V(45Gy) and mean dose for the prone position was 5.6±12.1% and 18.4±6.2Gy (ranges indicate standard deviations); for the supine position the corresponding dose values were 12.9±15.8% and 24.7±8.8Gy. For the bladder, the V(30Gy) and mean dose for prone position were 68.7±12.7% and 38.4±3.3Gy; for supine position these dose values were 77.1±13.7% and 40.7±3.1Gy. Conclusion: There is evidence of significant rotational instability in the prone position. The OAR dosimetry study indicates that there are some patients that may still benefit from the prone position, though many patients can be safely treated supine.

  16. A comparative dosimetric study of neoadjuvant 3D conformal radiotherapy for operable rectal cancer patients versus conventional 2D radiotherapy in NCI-airo

    Institute of Scientific and Technical Information of China (English)

    Mohamed Mahmoud; Hesham A. EL-Hossiny; Nashaat A. Diab; Marwa A. EL Razek

    2012-01-01

    Objective: This study was to compare this multiple-field conformal technique to the AP-PA technique with respect to target volume coverage and dose to normal tissues.Methods: We conducted a single institutional prospective comparative dosimetric analysis of 22 patients who received neoadjuvant radiation therapy for rectal cancer presented to radiotherapy department in National Cancer Institute, Cairo in period between June 2010 to September 2011 using 3D conformal radiotherapy technique for each patient, a second radiotherapy treatment plan was done using an anteroposterior (AP-PA) fields, the two techniques were then compared using dose volume histogram (DVH) analysis.Results: Comparing different DVHs, it was found that the planning target volume (PTV) was adequately covered in both ( 3D & 2D ) plans while it was demonstrates that this multiple field conformal technique produces superior distribution compared to 2D technique, with considerable sparing of bladder, ovaries and head of both femora.Conclusion: From the present study, it shows that it is recommended to use 3D planning for preoperative cases of cancer rectum so far it produces good coverage of the target as well as good sparing of the surrounding critical organs.

  17. Dosimetric rationale and early experience at UFPTI of thoracic proton therapy and chemotherapy in limited-stage small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Colaco, Rovel J.; Huh, Soon; Nichols, Romaine; Morris, Christopher G.; Flampouri, Stella; Li, Zuofeng; Hoppe, Bradford S. [Univ. of Florida Proton Therapy Inst., Jacksonville (United States)], e-mail: bhoppe@floridaproton.org; D' Agostino, Harry [Dept. of Thoracic Surgery, Univ. of Florida Coll. of Medicine, Gainesville (United States); Pham, Dat C. [Dept. of Hematology and Medical Oncology, Univ. of Florida Coll. of Medicine, Gainesville (United States); Bajwa, Abubakr A. [Dept. of Medicine, Univ. of Florida Coll. of Medicine, Gainesville (United States)

    2013-04-15

    Background: Concurrent chemoradiotherapy (CRT) is the standard of care in patients with limited-stage small cell lung cancer (SCLC). Treatment with conventional x-ray therapy (XRT) is associated with high toxicity rates, particularly acute grade 3+ esophagitis and pneumonitis. We present outcomes for the first known series of limited-stage SCLC patients treated with proton therapy and a dosimetric comparison of lung and esophageal doses with intensity-modulated radiation therapy (IMRT). Material and methods: Six patients were treated; five concurrently and one sequentially. Five patients received 60-66 CGE in 30-34 fractions once daily and one patient received 45 CGE in 30 fractions twice daily. All six patients received prophylactic cranial irradiation. Common Terminology Criteria for Adverse Events, v3.0, was used to grade toxicity. IMRT plans were also generated and compared with proton plans. Results: The median follow-up was 12.0 months. The one-year overall and progression-free survival rates were 83% and 66%, respectively. There were no cases of acute grade 3+ esophagitis or acute grade 2+ pneumonitis, and no other acute grade 3+ non-hematological toxicities were seen. One patient with a history of pulmonary fibrosis and atrial fibrillation developed worsening symptoms four months after treatment requiring oxygen. Three patients died; two of progressive disease and one after a fall. The latter patient was disease-free at 36 months after treatment. Another patient recurred and is alive, while two patients remain disease-free at 12 months of follow-up. Proton therapy proved superior to IMRT across all esophageal and lung dose volume points. Conclusion. In this small series of SCLC patients treated with proton therapy with radical intent, treatment was well tolerated with no cases of acute grade 3+ esophagitis or acute grade 2+ pneumonitis. Dosimetric comparison showed better sparing of lung and esophagus with proton therapy. Proton therapy merits further

  18. Assessment of Monte Carlo algorithm for compliance with RTOG 0915 dosimetric criteria in peripheral lung cancer patients treated with stereotactic body radiotherapy.

    Science.gov (United States)

    Pokhrel, Damodar; Sood, Sumit; Badkul, Rajeev; Jiang, Hongyu; McClinton, Christopher; Lominska, Christopher; Kumar, Parvesh; Wang, Fen

    2016-05-08

    The purpose of the study was to evaluate Monte Carlo-generated dose distributions with the X-ray Voxel Monte Carlo (XVMC) algorithm in the treatment of peripheral lung cancer patients using stereotactic body radiotherapy (SBRT) with non-protocol dose-volume normalization and to assess plan outcomes utilizing RTOG 0915 dosimetric compliance criteria. The Radiation Therapy Oncology Group (RTOG) protocols for non-small cell lung cancer (NSCLC) currently require radiation dose to be calculated using tissue density heterogeneity corrections. Dosimetric criteria of RTOG 0915 were established based on superposition/convolution or heterogeneities corrected pencil beam (PB-hete) algorithms for dose calculations. Clinically, more accurate Monte Carlo (MC)-based algorithms are now routinely used for lung stereotactic body radiotherapy (SBRT) dose calculations. Hence, it is important to determine whether MC calculations in the delivery of lung SBRT can achieve RTOG standards. In this report, we evaluate iPlan generated MC plans for peripheral lung cancer patients treated with SBRT using dose-volume histogram (DVH) normalization to determine if the RTOG 0915 compliance criteria can be met. This study evaluated 20 Stage I-II NSCLC patients with peripherally located lung tumors, who underwent MC-based SBRT with heterogeneity correction using X-ray Voxel Monte Carlo (XVMC) algorithm (Brainlab iPlan version 4.1.2). Total dose of 50 to 54 Gy in 3 to 5 fractions was delivered to the planning target vol-ume (PTV) with at least 95% of the PTV receiving 100% of the prescription dose (V100% ≥ 95%). The internal target volume (ITV) was delineated on maximum intensity projection (MIP) images of 4D CT scans. The PTV included the ITV plus 5 mm uniform margin applied to the ITV. The PTV ranged from 11.1 to 163.0 cc (mean = 46.1 ± 38.7 cc). Organs at risk (OARs) including ribs were delineated on mean intensity projection (MeanIP) images of 4D CT scans. Optimal clinical MC SBRT plans were

  19. LaRC local area networks to support distributed computing

    Science.gov (United States)

    Riddle, E. P.

    1984-01-01

    The Langley Research Center's (LaRC) Local Area Network (LAN) effort is discussed. LaRC initiated the development of a LAN to support a growing distributed computing environment at the Center. The purpose of the network is to provide an improved capability (over inteactive and RJE terminal access) for sharing multivendor computer resources. Specifically, the network will provide a data highway for the transfer of files between mainframe computers, minicomputers, work stations, and personal computers. An important influence on the overall network design was the vital need of LaRC researchers to efficiently utilize the large CDC mainframe computers in the central scientific computing facility. Although there was a steady migration from a centralized to a distributed computing environment at LaRC in recent years, the work load on the central resources increased. Major emphasis in the network design was on communication with the central resources within the distributed environment. The network to be implemented will allow researchers to utilize the central resources, distributed minicomputers, work stations, and personal computers to obtain the proper level of computing power to efficiently perform their jobs.

  20. Dosimetric comparison of partial and whole breast external beam irradiation in the treatment of early stage breast cancer.

    Science.gov (United States)

    Kim, Yongbok; Parda, David S; Trombetta, Mark G; Colonias, Athanasios; Werts, E Day; Miller, Linda; Miften, Moyed

    2007-12-01

    A dosimetric comparison was performed on external-beam three-dimensional conformal partial breast irradiation (PBI) and whole breast irradiation (WBI) plans for patients enrolled in the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-39/Radiation Therapy Oncology Group (RTOG) 0413 protocol at our institution. Twenty-four consecutive patients were treated with either PBI (12 patients) or WBI (12 patients). In the PBI arm, the lumpectomy cavity was treated to a total dose of 38.5 Gy at 3.85 Gy per fraction twice daily using a four-field noncoplanar beam setup. A minimum 6 h interval was required between fractions. In the WBI arm, the whole breast including the entirety of the lumpectomy cavity was treated to a total dose of 50.4 Gy at 1.8 Gy per fraction daily using opposed tangential beams. The lumpectomy cavity volume, planning target volume for evaluation (PTV_EVAL), and critical structure volumes were contoured for both the PBI and WBI patients. Dosimetric parameters, dose volume histograms (DVHs), and generalized equivalent uniform dose (gEUD) for target and critical structures were compared. Dosimetric results show the PBI plans, compared to the WBI plans, have smaller hot spots in the PTV_EVAL (maximum dose: 104.2% versus 110.9%) and reduced dose to the ipsilateral breast (V50: 48.6% versus 92.1% and V100: 10.2% versus 50.5%), contralateral breast (V3: 0.16% versus 2.04%), ipsilateral lung (V30: 5.8% versus 12.7%), and thyroid (maximum dose: 0.5% versus 2.0%) with p values < or = 0.01. However, similar dose coverage of the PTV_EVAL (98% for PBI and 99% for WBI, on average) was observed and the dose difference for other critical structures was clinically insignificant in both arms. The gEUD data analysis showed the reduction of dose to the ipsilateral breast and lung, contralateral breast and thyroid. In addition, preliminary dermatologic adverse event assessment data suggested reduced skin toxicity for patients treated with the PBI technique.

  1. Dosimetric verification of IMRT treatment plans at the German Cancer Research Center (DKFZ); Dosimetrische Verifikation von IMRT-Gesamtplaenen am Deutschen Krebsforschungszentrum Heidelberg

    Energy Technology Data Exchange (ETDEWEB)

    Rhein, B.; Haering, P.; Debus, J.; Schlegel, W. [Deutsches Krebsforschungszentrum, Heidelberg (Germany)

    2002-07-01

    The present paper describes a method for the individual dosimetric verification of IMRT treatment plans. The German Cancer Research Center (Deutsches Krebsforschungszentrum; DKFZ) has implemented the intensity modulated radiotherapy (IMRT) since 1997. So far, 246 patients with head and neck cancer, cancer of the prostate, breast, and vertebral column, as well as mesothelioma of the pleura have been treated. Every IMRT plan is transferred into a special IMRT verification phantom, recalculated, and dosimetrically verified. Absolute dose distributions are measured with Kodak EDR films and compared with the results of the dose calculation. After correction of the optical density in relationship to the dose, EDR films are able to measure the absolute dose with an accuracy of {+-}2% compared to an ionization chamber. A Visual C{sup ++} software tool has been developed to correlate and evaluate the film dose distributions with the corresponding slices of the 3D dose cube. Beside the overlay of absolute or relative isodoses and dose profiles, the median dose within correlated regions of interest (ROIs) is also included in the quantitative dose evaluation. The deviation between EDR film dosimetry and dose calculation is {delta}D=-0.3%{+-}2.3%. After introduction of the verification software, the total verification time (including handling, correlation, evaluation, and documentation of the data), could be reduced to less than 2 hours. (orig.) [German] In dieser Arbeit wird eine Methode zur individuellen dosimetrischen Ueberpruefung von IMRT-Bestrahlungsplaenen beschrieben. Am Deutschen Krebsforschungszentrum (DKFZ) wird die intensitaetsmodulierte Strahlentherapie (IMRT) seit 1997 durchgefuehrt. 246 Patienten mit Tumoren im Kopf-Hals Bereich, der Wirbelsaeule, der Prostata, der weiblichen Brust und Pleuramesotheliome wurden bisher bestrahlt. Jeder IMRT-Bestrahlungsplan wird in ein spezielles Verifikationsphantom uebertragen, dort neu berechnet und dosimetrisch verifiziert

  2. Postoperative Radiotherapy for Prostate Cancer: A Comparison of Four Consensus Guidelines and Dosimetric Evaluation of 3D-CRT Versus Tomotherapy IMRT

    Energy Technology Data Exchange (ETDEWEB)

    Malone, Shawn, E-mail: smalone@ottawahospital.on.ca [Division of Radiation Oncology, Ottawa Hospital, University of Ottawa, Ottawa, Ontario (Canada); Croke, Jennifer [Division of Radiation Oncology, Ottawa Hospital, University of Ottawa, Ottawa, Ontario (Canada); Roustan-Delatour, Nicolas; Belanger, Eric [Department of Pathology, Ottawa Hospital, University of Ottawa, Ottawa, Ontario (Canada); Avruch, Leonard [Department of Radiology, Ottawa Hospital, University of Ottawa, Ottawa, Ontario (Canada); Malone, Colin [Division of Radiation Oncology, Ottawa Hospital, University of Ottawa, Ottawa, Ontario (Canada); Morash, Christopher [Division of Urology, Ottawa Hospital, University of Ottawa, Ottawa, Ontario (Canada); Kayser, Cathleen; Underhill, Kathryn; Li Yan; Malone, Kyle [Division of Radiation Oncology, Ottawa Hospital, University of Ottawa, Ottawa, Ontario (Canada); Nyiri, Balazs [Department of Medical Physics, Ottawa Hospital, University of Ottawa, Ottawa, Ontario (Canada); Spaans, Johanna [Division of Radiation Oncology, Ottawa Hospital, University of Ottawa, Ottawa, Ontario (Canada)

    2012-11-01

    Purpose: Despite the benefits of adjuvant radiotherapy after radical prostatectomy, approximately one-half of patients relapse. Four consensus guidelines have been published (European Organization for Research and Treatment of Cancer, Faculty of Radiation Oncology Genito-Urinary Group, Princess Margaret Hospital, Radiation Therapy Oncology Group) with the aim of standardizing the clinical target volume (CTV) delineation and improve outcomes. To date, no attempt has been made to compare these guidelines in terms of treatment volumes or organ at risk (OAR) irradiation. The extent to which the guideline-derived plans meet the dosimetric constraints of present trials or of the Quantitative Analysis of Normal Tissue Effects in the Clinic (QUANTEC) trial is also unknown. Our study also explored the dosimetric benefits of intensity-modulated radiotherapy (IMRT). Methods and Materials: A total of 20 patients treated with postoperative RT were included. The three-dimensional conformal radiotherapy (3D-CRT) plans were applied to cover the guideline-generated planning target volumes (66 Gy in 33 fractions). Dose-volume histograms (DVHs) were analyzed for CTV/planning target volume coverage and to evaluate OAR irradiation. The OAR DVHs were compared with the constraints proposed in the QUANTEC and Radiotherapy and Androgen Deprivation In Combination After Local Surgery (RADICALS) trials. 3D-CRT plans were compared with the tomotherapy plans for the Radiation Therapy Oncology Group planning target volume to evaluate the advantages of IMRT. Results: The CTV differed significantly between guidelines (p < 0.001). The European Organization for Research and Treatment of Cancer-CTVs were significantly smaller than the other CTVs (p < 0.001). Differences in prostate bed coverage superiorly accounted for the major volumetric differences between the guidelines. Using 3D-CRT, the DVHs rarely met the QUANTEC or RADICALS rectal constraints, independent of the guideline used. The RADICALS

  3. Dosimetric comparison of hybrid volumetric-modulated arc therapy, volumetric-modulated arc therapy, and intensity-modulated radiation therapy for left-sided early breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jia-Fu [Department of Radiation Physics, Taichung Veterans General Hospital, Taichung, Taiwan (China); Yeh, Dah-Cherng [Department of General Surgery, Taichung Veterans General Hospital, Taichung, Taiwan (China); Yeh, Hui-Ling, E-mail: hlyeh@vghtc.gov.tw [Department of Radiation Oncology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Chang, Chen-Fa [Department of Radiation Physics, Taichung Veterans General Hospital, Taichung, Taiwan (China); Lin, Jin-Ching [Department of Radiation Oncology, Taichung Veterans General Hospital, Taichung, Taiwan (China)

    2015-10-01

    To compare the dosimetric performance of 3 different treatment techniques: hybrid volumetric-modulated arc therapy (hybrid-VMAT), pure-VMAT, and fixed-field intensity-modulated radiation therapy (F-IMRT) for whole-breast irradiation of left-sided early breast cancer. The hybrid-VMAT treatment technique and 2 other treatment techniques—pure-VMAT and F-IMRT—were compared retrospectively in 10 patients with left-sided early breast cancer. The treatment plans of these patients were replanned using the same contours based on the original computed tomography (CT) data sets. Dosimetric parameters were calculated to evaluate plan quality. Total monitor units (MUs) and delivery time were also recorded and evaluated. The hybrid-VMAT plan generated the best results in dose coverage of the target and the dose uniformity inside the target (p < 0.0001 for conformal index [CI]; p = 0.0002 for homogeneity index [HI] of planning target volume [PTV]{sub 50.4} {sub Gy} and p < 0.0001 for HI of PTV{sub 62} {sub Gy}). Volumes of ipsilateral lung irradiated to doses of 20 Gy (V{sub 20} {sub Gy}) and 5 Gy (V{sub 5} {sub Gy}) by the hybrid-VMAT plan were significantly less than those of the F-IMRT and the pure-VMAT plans. The volume of ipsilateral lung irradiated to a dose of 5 Gy was significantly less using the hybrid-VMAT plan than that using the F-IMRT or the pure-VMAT plan. The total mean MUs for the hybrid-VMAT plan were significantly less than those for the F-IMRT or the pure-VMAT plan. The mean machine delivery time was 3.23 ± 0.29 minutes for the hybrid-VMAT plans, which is longer than that for the pure-VMAT plans but shorter than that for the F-IMRT plans. The hybrid-VMAT plan is feasible for whole-breast irradiation of left-sided early breast cancer.

  4. Dosimetric evaluation of integrated IMRT treatment of the chest wall and supraclavicular region for breast cancer after modified radical mastectomy

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Bo; Wei, Xian-ding; Zhao, Yu-tian [Department of Radiation Oncology, the Fourth Affiliated Hospital of Suzhou University, Wuxi (China); Ma, Chang-Ming, E-mail: charlie.ma@fccc.edu [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA (United States)

    2014-07-01

    To investigate the dosimetric characteristics of irradiation of the chest wall and supraclavicular region as an integrated volume with intensity-modulated radiation therapy (IMRT) after modified radical mastectomy. This study included 246 patients who received modified radical mastectomy. The patients were scanned with computed tomography, and the chest wall (with or without the internal mammary lymph nodes) and supraclavicular region were delineated. For 143 patients, the chest wall and supraclavicular region were combined as an integrated planning volume and treated with IMRT. For 103 patients, conventional treatments were employed with 2 tangential fields for the chest wall, abutting a mixed field of 6-MV x-rays (16 Gy) and 9-MeV electrons (34 Gy) for the upper supraclavicular region. The common prescription dose was 50 Gy/25 Fx/5 W to 90% of the target volume. The dosimetric characteristics of the chest wall, the supraclavicular region, and normal organs were compared. For the chest wall target, compared with conventional treatments, the integrated IMRT plans lowered the maximum dose, increased the minimum dose, and resulted in better conformity and uniformity of the target volume. There was an increase in minimum, average, and 95% prescription dose for the integrated IMRT plans in the supraclavicular region, and conformity and uniformity were improved. The V{sub 30} of the ipsilateral lung and V{sub 10}, V{sub 30}, and mean dose of the heart on the integrated IMRT plans were lower than those of the conventional plans. The V{sub 5} and V{sub 10} of the ipsilateral lung and V{sub 5} of the heart were higher on the integrated IMRT plans (p < 0.05) than on conventional plans. Without an increase in the radiation dose to organs at risk, the integrated IMRT treatment plans improved the dose distribution of the supraclavicular region and showed better dose conformity and uniformity of the integrated target volume of the chest wall and supraclavicular region.

  5. SU-E-P-58: Dosimetric Study of Conventional Intensity-Modulated Radiotherapy and Knowledge-Based Radiation Therapy for Postoperation of Cervix Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ma, C; Yin, Y [Shandong Tumor Hospital, Jinan, Shandong Provice (China)

    2015-06-15

    Purpose: To compare the dosimetric difference of the target volume and organs at risk(OARs) between conventional intensity-modulated radiotherapy(C-IMRT) and knowledge-based radiation therapy (KBRT) plans for cervix cancer. Methods: 39 patients with cervical cancer after surgery were randomly selected, 20 patient plans were used to create the model, the other 19 cases used for comparative evaluation. All plans were designed in Eclipse system. The prescription dose was 30.6Gy, 17 fractions, OARs dose satisfied to the clinical requirement. A paired t test was used to evaluate the differences of dose-volume histograms (DVH). Results: Comparaed to C-IMRT plan, the KBRT plan target can achieve the similar target dose coverage, D98,D95,D2,HI and CI had no difference (P≥0.05). The dose of rectum, bladder and femoral heads had no significant differences(P≥0.05). The time was used to design treatment plan was significant reduced. Conclusion: This study shows that postoperative radiotherapy of cervical KBRT plans can achieve the similar target and OARs dose, but the shorter designing time.

  6. Dosimetric evaluation of the skin-sparing effects of 3-dimensional conformal radiotherapy and intensity-modulated radiotherapy for left breast cancer.

    Science.gov (United States)

    Jo, In Young; Kim, Shin-Wook; Son, Seok Hyun

    2017-01-10

    The purpose of this study was to evaluate the skin-sparing effects of 3-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT) in patients with early left-sided breast cancer. Twenty left breast cancer patients treated with whole breast radiotherapy following breast-conserving surgery were enrolled in this study, and the 3D-CRT and IMRT plans were generated for each patient. To evaluate the dose delivered to the skin, 2 mm thickness skin (2-mm skin) and 3 mm thickness skin (3-mm skin) were contoured and a dosimetric comparison between the 2 plans was performed. The target volume coverage was better in IMRT than in 3D-CRT. The mean dose was 50.8 Gy for 3D-CRT and 51.1 Gy for IMRT. V40Gy was 99.4% for 3D-CRT and 99.9% for IMRT. In the case of skin, the mean dose was higher in 3D-CRT than in IMRT (mean dose of 2-mm skin: 32.8 Gy and 24.2 Gy; mean dose of 3-mm skin: 37.2 Gy and 27.8 Gy, for 3D-CRT and IMRT, respectively). These results indicated that the skin-sparing effect is more prominent in IMRT compared to 3D-CRT without compromising the target volume coverage.

  7. SU-E-P-56: Dosimetric Comparison of Three Post Modified Radical Mastectomy Radiotherapy Techniques for Locally Advanced Left-Sided Breast Cancer and Beyond

    Energy Technology Data Exchange (ETDEWEB)

    Ma, C; Zhang, W; Lu, J; Wu, L; Wu, F; Huang, B; Li, D [Cancer Hospital of Shantou University Medical College, Shantou, Guangdong (China)

    2015-06-15

    Purpose: To compare the dosimetry of post modified radical mastectomy radiotherapy (PMRMRT) for left-sided breast cancer using 3-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT). Methods: We created ten sets of PMRMRT plans for ten consecutive patients and utilized two tangential and one or two supraclavicular beams in 3DCRT, a total of 5 beams in IMRT and two optimized partial arcs in VMAT. The difference in results between any two of the three new plans, between new and previous 3DCRT plans were compared and analyzed by ANOVA (α =0.05) and paired-sample t-test respectively. P values less than 0.05 were considered statistically significant. Results: Both IMRT and VMAT plans had similar PTV coverage, hotspot area and conformity (all p>0.05), and significantly higher PTV coverage compared with new 3DCRT (both p<0.001). IMRT plans had significantly less heart and left lung radiation exposure compared with VMAT (all p<0.05). The 3DCRT plans with larger estimated CTV displacement had better target coverage but worse OARs sparing compared to those with smaller one. Conclusion: IMRT has dosimetrical advantages over the other two techniques in PMRMRT for left-sided breast cancer. Individually quantifying and minimizing CTV displacement can significantly improve dosage distribution. This work was supported by the Medical Scientific Research Foundation of Guangdong Procvince (A2014455 to Changchun Ma)

  8. Dosimetric study of RapidArc plans with flattened beam (FB and flattening filter-free (FFF beam for localized prostate cancer based on physical indices

    Directory of Open Access Journals (Sweden)

    Birendra Kumar Rout

    2014-12-01

    Full Text Available Purpose: To identify the continual diversity between flattening photon beam (FB and Flattening Filter Free (FFF photon beams for localized prostate cancer; and to determine potential benefits and drawbacks of using unflattened beam for this type of treatment.Methods: Eight prostate cases including seminal vesicles selected for this study. The primary planning target volume (PTVP and boost planning target volume (PTVB were contoured. The total prescription dose was 78 Gy (56 Gy to PTVP and an additional 22 Gy to PTVB. For all cases, treatment plans using 6MV with FB and FFF beams with identical dose-volume constraints, arc angles and number of arcs were developed. The dose volume histograms for both techniques were compared for primary target volume and critical structures.Results: A low Sigma index (FFF: 1.65 + 0.361; FB: 1.725 + 0.39 indicating improved dose homogeneity in FFF beam. Conformity index (FFF: 0.994 + 0.01; FB: 0.993 + 0.01 is comparable for both techniques. Minimal difference of Organ at risk mean dose was observed. Normal tissue integral dose in FB plan resulted 1.5% lower than FFF plan. All the plans displayed significant increase (1.18 times for PTVP and 1.11 for PTBB in the average number of necessary MU with FFF beam.Conclusion: Diversity between FB and FFF beam plans were found. FFF beam accelerator has been utilized to develop clinically acceptable Rapid Arc treatment plans for prostate cancer with 6 MV.---------------------------------Cite this article as: Rout BK, Muralidhar KR, Ali M, Shekar MC, Kumar A. Dosimetric study of RapidArc plans with flattened beam (FB and flattening filter-free (FFF beam for localized prostate cancer based on physical indices. Int J Cancer Ther Oncol 2014; 2(4:02046.  DOI: 10.14319/ijcto.0204.6

  9. Volumetric modulated arc radiotherapy of the whole larynx, followed by a single affected vocal cord, for T1a glottic cancer: Dosimetric analysis of a case.

    Science.gov (United States)

    Yeo, Seung-Gu

    2016-03-01

    Radiation therapy (RT) and endolaryngeal surgery are standard treatments for early-stage glottic cancer. They have closely matched oncological outcomes; however, it is debatable which method is superior in terms of functional outcomes. Several dosimetric studies have demonstrated that, compared with conventional RT, intensity-modulated RT (IMRT) reduces unnecessary radiation of the adjacent normal tissues, including the carotid artery and thyroid gland. However, RT targets the whole larynx, whereas endolaryngeal surgery is a highly focused treatment involving the en bloc resection of a tumor with safety margins. For T1a glottic cancer, in which the tumor is limited to one vocal cord, the technical feasibility of targeting IMRT on the single vocal cord affected has been investigated; however, the clinical feasibility and the possibility of inferior local control remain to be elucidated. In the present case study, IMRT was used to treat the whole larynx first, and then to treat a single vocal cord. The patient in the present study had T1a glottic cancer, and received volumetric modulated arc therapy with a total dose of 63 Gy/28 fractions. The first treatment phase (40.5 Gy/18 fractions) targeted the whole larynx to eliminate subclinical disease. The second treatment phase (22.5 Gy/10 fractions) targeted only the involved vocal cord. During this treatment phase, the exposure of the non-involved right vocal cord, the right carotid artery and the thyroid gland to the radiation was lower compared with the continuation of the initial treatment approach. These findings suggested that changing the target volume from the whole larynx to the affected vocal cord during the course of IMRT is feasible for T1a glottic cancer, and that it may reduce functional side effects while maintaining oncological outcomes.

  10. SU-E-J-94: Geometric and Dosimetric Evaluation of Deformation Image Registration Algorithms Using Virtual Phantoms Generated From Patients with Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Z; Greskovich, J; Xia, P [The Cleveland Clinic, Cleveland, OH (United States); Bzdusek, K [Philips, Fitchburg, WI (United States)

    2015-06-15

    Purpose: To generate virtual phantoms with clinically relevant deformation and use them to objectively evaluate geometric and dosimetric uncertainties of deformable image registration (DIR) algorithms. Methods: Ten lung cancer patients undergoing adaptive 3DCRT planning were selected. For each patient, a pair of planning CT (pCT) and replanning CT (rCT) were used as the basis for virtual phantom generation. Manually adjusted meshes were created for selected ROIs (e.g. PTV, lungs, spinal cord, esophagus, and heart) on pCT and rCT. The mesh vertices were input into a thin-plate spline algorithm to generate a reference displacement vector field (DVF). The reference DVF was used to deform pCT to generate a simulated replanning CT (srCT) that was closely matched to rCT. Three DIR algorithms (Demons, B-Spline, and intensity-based) were applied to these ten virtual phantoms. The images, ROIs, and doses were mapped from pCT to srCT using the DVFs computed by these three DIRs and compared to those mapped using the reference DVF. Results: The average Dice coefficients for selected ROIs were from 0.85 to 0.96 for Demons, from 0.86 to 0.97 for intensity-based, and from 0.76 to 0.95 for B-Spline. The average Hausdorff distances for selected ROIs were from 2.2 to 5.4 mm for Demons, from 2.3 to 6.8 mm for intensity-based, and from 2.4 to 11.4 mm for B-Spline. The average absolute dose errors for selected ROIs were from 0.2 to 0.6 Gy for Demons, from 0.1 to 0.5 Gy for intensity-based, and from 0.5 to 1.5 Gy for B-Spline. Conclusion: Virtual phantoms were modeled after patients with lung cancer and were clinically relevant for adaptive radiotherapy treatment replanning. Virtual phantoms with known DVFs serve as references and can provide a fair comparison when evaluating different DIRs. Demons and intensity-based DIRs were shown to have smaller geometric and dosimetric uncertainties than B-Spline. Z Shen: None; K Bzdusek: an employee of Philips Healthcare; J Greskovich: None; P Xia

  11. A dosimetric study of volumetric modulated arc therapy planning techniques for treatment of low-risk prostate cancer in patients with bilateral hip prostheses

    Directory of Open Access Journals (Sweden)

    Suresh B Rana

    2014-01-01

    Full Text Available Background and Purpose: Recently, megavoltage (MV photon volumetric modulated arc therapy (VMAT has gained widespread acceptance as the technique of choice for prostate cancer patients undergoing external beam radiation therapy. However, radiation treatment planning for patients with metallic hip prostheses composed of high-Z materials can be challenging due to (1 presence of streak artifacts from prosthetic hips in computed tomography dataset, and (2 inhomogeneous dose distribution within the target volume. The purpose of this study was to compare the dosimetric quality of VMAT techniques in the form of Rapid Arc (RA for treating low-risk prostate cancer patient with bilateral prostheses. Materials and Methods: Three treatment plans were created using RA techniques utilizing 2 arcs (2-RA, 3 arcs (3-RA, and 4 arcs (4-RA for 6 MV photon beam in Eclipse treatment planning system. Each plan was optimized for total dose of 79.2 Gy prescribed to the planning target volume (PTV over 44 fractions. All three RA plans were calculated with anisotropic analytical algorithm. Results : The mean and maximum doses to the PTV as well as the homogeneity index among all three RA plans were comparable. The plan conformity index was highest in the 2-Arc plan (1.19 and lowest in the 4-Arc plan (1.10. In comparison to the 2-RA technique, the 4-RA technique reduced the doses to rectum by up to 18.8% and to bladder by up to 7.8%. In comparison to the 3-RA technique, the 4-RA technique reduced the doses to rectum by up to 14.6% and to bladder by up to 3.5%. Conclusion: Based on the RA techniques investigated for a low-risk prostate cancer patient with bilateral prostheses, the 4-RA plan produced lower rectal and bladder dose and better dose conformity across the PTV in comparison with the 2-RA and 3-RA plans.

  12. Dosimetric benefits of IMRT and VMAT in the treatment of middle thoracic esophageal cancer: is the conformal radiotherapy still an alternative option?

    Science.gov (United States)

    Wu, Zhiqin; Xie, Congying; Hu, Meilong; Han, Ce; Yi, Jinling; Zhou, Yongqiang; Yuan, Huawei; Jin, Xiance

    2014-05-08

    The purpose of this study is to investigate the dosimetric differences among conformal radiotherapy (CRT), intensity-modulated radiotherapy (IMRT), and volumetric-modulated radiotherapy (VMAT) in the treatment of middle thoracic esophageal cancer, and determine the most appropriate treatment modality. IMRT and one-arc VMAT plans were generated for eight middle thoracic esophageal cancer patients treated previous with CRT. The planning target volume (PTV) coverage and protections on organs at risk of three planning schemes were compared. All plans have sufficient PTV coverage and no significant differences were observed, except for the conformity and homogeneity. The lung V5, V10, and V13 in CRT were 47.9% ± 6.1%, 36.5% ± 4.6%, and 33.2% ± 4.2%, respectively, which were greatly increased to 78.2% ± 13.7% (p VMAT, respectively. The lung V20 (p = 0.03) in VMAT and the V30 (p = 0.04) in IMRT were lower than those in CRT. Both IMRT and VMAT achieved a better protection on heart. However, the volumes of the healthy tissue outside of PTV irradiated by a low dose were higher for IMRT and VMAT. IMRT and VMAT also had a higher MU, optimization time, and delivery time compared to CRT. In conclusion, all CRT, IMRT, and VMAT plans are able to meet the prescription and there is no clear distinction on PTV coverage. IMRT and VMAT can only decrease the volume of lung and heart receiving a high dose, but at a cost of delivering low dose to more volume of lung and normal tissues. CRT is still a feasible option for middle thoracic esophageal cancer radiotherapy, especially for the cost-effective consideration.

  13. SU-E-T-125: Dosimetric Comparison of Intensity Modulated Radiation Therapy Using Robotic Versus Traditional Linac Platform in Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, T; Rella, J [Alliance Oncology, Newburyport, MA (United States); Yang, J [Alliance Oncology, Newburyport, MA (United States); Drexel University, Philadelphia, PA (United States); Sims, C [Accuray Inc., Sunnyvale, CA (United States); Fung, C [Commonwealth Hematology Oncology, Newburyport, MA (United States)

    2014-06-01

    Purpose: Recent development of an MLC for robotic external beam radiotherapy has the potential of new clinical application in conventionally fractionated radiation therapy. This study offers a dosimetric comparison of IMRT plans using Cyberknife with MLC versus conventional linac plans. Methods: Ten prostate cancer patients treated on a traditional linac with IMRT to 7920cGy at 180cGy/fraction were randomly selected. GTVs were defined as prostate plus proximal seminal vesicles. PTVs were defined as GTV+8mm in all directions except 5mm posteriorly. Conventional IMRT planning was performed on Philips Pinnacle and delivered on a standard linac with CBCT and 10mm collimator leaf width. For each case a Cyberknife plan was created using Accuray Multiplan with same CT data set, contours, and dose constraints. All dosimetric data was transferred to third party software for independent computation of contour volumes and DVH. Delivery efficiency was evaluated using total MU, treatment time, number of beams, and number of segments. Results: Evaluation criteria including percent target coverage, homogeneity index, and conformity index were found to be comparable. All dose constraints from QUANTEC were found to be statistically similar except rectum V50Gy and bladder V65Gy. Average rectum V50Gy was lower for robotic IMRT (30.07%±6.57) versus traditional (34.73%±3.62, p=0.0130). Average bladder V65Gy was lower for robotic (17.87%±12.74) versus traditional (21.03%±11.93, p=0.0405). Linac plans utilized 9 coplanar beams, 48.9±3.8 segments, and 19381±2399MU. Robotic plans utilized 38.4±9.0 non-coplanar beams, 85.5±21.0 segments and 42554.71±16381.54 MU. The average treatment was 15.02±0.60 minutes for traditional versus 20.90±2.51 for robotic. Conclusion: The robotic IMRT plans were comparable to the traditional IMRT plans in meeting the target volume dose objectives. Critical structure dose constraints were largely comparable although statistically significant

  14. The dosimetric impact of daily setup error on target volumes and surrounding normal tissue in the treatment of prostate cancer with intensity-modulated radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Algan, Ozer, E-mail: oalgan@ouhsc.edu [Department of Radiation Oncology, Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States); Jamgade, Ambarish; Ali, Imad; Christie, Alana; Thompson, J. Spencer; Thompson, David; Ahmad, Salahuddin; Herman, Terence [Department of Radiation Oncology, Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK (United States)

    2012-01-01

    The purpose of this study was to evaluate the impact of daily setup error and interfraction organ motion on the overall dosimetric radiation treatment plans. Twelve patients undergoing definitive intensity-modulated radiation therapy (IMRT) treatments for prostate cancer were evaluated in this institutional review board-approved study. Each patient had fiducial markers placed into the prostate gland before treatment planning computed tomography scan. IMRT plans were generated using the Eclipse treatment planning system. Each patient was treated to a dose of 8100 cGy given in 45 fractions. In this study, we retrospectively created a plan for each treatment day that had a shift available. To calculate the dose, the patient would have received under this plan, we mathematically 'negated' the shift by moving the isocenter in the exact opposite direction of the shift. The individualized daily plans were combined to generate an overall plan sum. The dose distributions from these plans were compared with the treatment plans that were used to treat the patients. Three-hundred ninety daily shifts were negated and their corresponding plans evaluated. The mean isocenter shift based on the location of the fiducial markers was 3.3 {+-} 6.5 mm to the right, 1.6 {+-} 5.1 mm posteriorly, and 1.0 {+-} 5.0 mm along the caudal direction. The mean D95 doses for the prostate gland when setup error was corrected and uncorrected were 8228 and 7844 cGy (p < 0.002), respectively, and for the planning target volume (PTV8100) was 8089 and 7303 cGy (p < 0.001), respectively. The mean V95 values when patient setup was corrected and uncorrected were 99.9% and 87.3%, respectively, for the PTV8100 volume (p < 0.0001). At an individual patient level, the difference in the D95 value for the prostate volume could be >1200 cGy and for the PTV8100 could approach almost 2000 cGy when comparing corrected against uncorrected plans. There was no statistically significant difference in the D35

  15. The dosimetric impact of daily setup error on target volumes and surrounding normal tissue in the treatment of prostate cancer with intensity-modulated radiation therapy.

    Science.gov (United States)

    Algan, Ozer; Jamgade, Ambarish; Ali, Imad; Christie, Alana; Thompson, J Spencer; Thompson, David; Ahmad, Salahuddin; Herman, Terence

    2012-01-01

    The purpose of this study was to evaluate the impact of daily setup error and interfraction organ motion on the overall dosimetric radiation treatment plans. Twelve patients undergoing definitive intensity-modulated radiation therapy (IMRT) treatments for prostate cancer were evaluated in this institutional review board-approved study. Each patient had fiducial markers placed into the prostate gland before treatment planning computed tomography scan. IMRT plans were generated using the Eclipse treatment planning system. Each patient was treated to a dose of 8100 cGy given in 45 fractions. In this study, we retrospectively created a plan for each treatment day that had a shift available. To calculate the dose, the patient would have received under this plan, we mathematically "negated" the shift by moving the isocenter in the exact opposite direction of the shift. The individualized daily plans were combined to generate an overall plan sum. The dose distributions from these plans were compared with the treatment plans that were used to treat the patients. Three-hundred ninety daily shifts were negated and their corresponding plans evaluated. The mean isocenter shift based on the location of the fiducial markers was 3.3 ± 6.5 mm to the right, 1.6 ± 5.1 mm posteriorly, and 1.0 ± 5.0 mm along the caudal direction. The mean D95 doses for the prostate gland when setup error was corrected and uncorrected were 8228 and 7844 cGy (p 1200 cGy and for the PTV8100 could approach almost 2000 cGy when comparing corrected against uncorrected plans. There was no statistically significant difference in the D35 parameter for the surrounding normal tissue except for the dose received by the penile bulb and the right hip. Our dosimetric evaluation suggests significant underdosing with inaccurate target localization and emphasizes the importance of accurate patient setup and target localization. Further studies are needed to evaluate the impact of intrafraction organ motion, rotation

  16. Stereotactic body radiation therapy planning with duodenal sparing using volumetric-modulated arc therapy vs intensity-modulated radiation therapy in locally advanced pancreatic cancer: A dosimetric analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Rachit; Wild, Aaron T.; Ziegler, Mark A.; Hooker, Ted K.; Dah, Samson D.; Tran, Phuoc T.; Kang, Jun; Smith, Koren; Zeng, Jing [Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Hospital, 401N. Broadway, Weinberg Suite 1440, Baltimore, MD 21231 (United States); Pawlik, Timothy M. [Department of Surgery, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Tryggestad, Erik [Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Hospital, 401N. Broadway, Weinberg Suite 1440, Baltimore, MD 21231 (United States); Ford, Eric [Department of Radiation Oncology, Fred Hutchinson Cancer Center, University of Washington, Seattle, WA (United States); Herman, Joseph M., E-mail: jherma15@jhmi.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins Hospital, 401N. Broadway, Weinberg Suite 1440, Baltimore, MD 21231 (United States)

    2013-10-01

    Stereotactic body radiation therapy (SBRT) achieves excellent local control for locally advanced pancreatic cancer (LAPC), but may increase late duodenal toxicity. Volumetric-modulated arc therapy (VMAT) delivers intensity-modulated radiation therapy (IMRT) with a rotating gantry rather than multiple fixed beams. This study dosimetrically evaluates the feasibility of implementing duodenal constraints for SBRT using VMAT vs IMRT. Non–duodenal sparing (NS) and duodenal-sparing (DS) VMAT and IMRT plans delivering 25 Gy in 1 fraction were generated for 15 patients with LAPC. DS plans were constrained to duodenal D{sub max} of<30 Gy at any point. VMAT used 1 360° coplanar arc with 4° spacing between control points, whereas IMRT used 9 coplanar beams with fixed gantry positions at 40° angles. Dosimetric parameters for target volumes and organs at risk were compared for DS planning vs NS planning and VMAT vs IMRT using paired-sample Wilcoxon signed rank tests. Both DS VMAT and DS IMRT achieved significantly reduced duodenal D{sub mean}, D{sub max}, D{sub 1cc}, D{sub 4%}, and V{sub 20} {sub Gy} compared with NS plans (all p≤0.002). DS constraints compromised target coverage for IMRT as demonstrated by reduced V{sub 95%} (p = 0.01) and D{sub mean} (p = 0.02), but not for VMAT. DS constraints resulted in increased dose to right kidney, spinal cord, stomach, and liver for VMAT. Direct comparison of DS VMAT and DS IMRT revealed that VMAT was superior in sparing the left kidney (p<0.001) and the spinal cord (p<0.001), whereas IMRT was superior in sparing the stomach (p = 0.05) and the liver (p = 0.003). DS VMAT required 21% fewer monitor units (p<0.001) and delivered treatment 2.4 minutes faster (p<0.001) than DS IMRT. Implementing DS constraints during SBRT planning for LAPC can significantly reduce duodenal point or volumetric dose parameters for both VMAT and IMRT. The primary consequence of implementing DS constraints for VMAT is increased dose to other organs at

  17. Comprehensive dosimetric planning comparison for early-stage, non-small cell lung cancer with SABR: fixed-beam IMRT versus VMAT versus TomoTherapy.

    Science.gov (United States)

    Xhaferllari, Ilma; El-Sherif, Omar; Gaede, Stewart

    2016-09-08

    Volumetric-modulated arc therapy (VMAT) is emerging as a leading technology in treating early-stage, non-small cell lung cancer (NSCLC) with stereotactic ablative radiotherapy (SABR). However, two other modalities capable of deliver-ing intensity-modulated radiation therapy (IMRT) include fixed-beam and helical TomoTherapy (HT). This study aims to provide an extensive dosimetric compari-son among these various IMRT techniques for treating early-stage NSCLC with SABR. Ten early-stage NSCLC patients were retrospectively optimized using three fixed-beam techniques via nine to eleven beams (high and low modulation step-and-shoot (SS), and sliding window (SW)), two VMAT techniques via two partial arcs (SmartArc (SA) and RapidArc (RA)), and three HT techniques via three different fan beam widths (1 cm, 2.5 cm, and 5 cm) for 80 plans total. Fixed-beam and VMAT plans were generated using flattening filter-free beams. SS and SA, HT treatment plans, and SW and RA were optimized using Pinnacle v9.1, Tomoplan v.3.1.1, and Eclipse (Acuros XB v11.3 algorithm), respectively. Dose-volume histogram statistics, dose conformality, and treatment delivery efficiency were analyzed. VMAT treatment plans achieved significantly lower values for contralat-eral lung V5Gy (p ≤ 0.05) compared to the HT plans, and significantly lower mean lung dose (p VMAT techniques, a significant reduction in the total monitor units (p = 0.05) was found in the SA plans, while a significant decrease was observed in the dose falloff parameter, D2cm, (p = 0.05), for the RA treatments. The maximum cord dose was significantly reduced (p = 0.017) in grouped RA&SA plans com-pared to SS. Estimated treatment time was significantly higher for HT and fixed-beam plans compared to RA&SA (p VMAT is dosimetrically advantageous in treating early-stage NSCLC with SABR compared to fixed-beam, while providing significantly shorter treatment times.

  18. Dosimetric effect of intra-fractional and inter-fractional target motion in lung cancer radiotherapy techniques

    Directory of Open Access Journals (Sweden)

    Teerthraj Verma

    2015-12-01

    Full Text Available Purpose: The purpose of present study was to experimentally evaluate the dosimetric uncertainties in 3-dimensional conformal radiotherapy (3DCRT, dynamic intensity modulated radiotherapy (D-IMRT, step-shoot (SS-IMRT, and volumetric modulated arc therapy (VMAT treatment delivery techniques due to intra- and inter-fractional target motion. Methods: A previously treated lung patient was selected for this study and was replanned for 60 Gy in 30 fractions using four techniques (3DCRT, D-IMRT, SS-IMRT, and VMAT. These plans were delivered in a clinical linear accelerator equipped with HexaPOD™ evo RT System. The target dose of static QUASAR phantom was calculated that served as reference dose to the target. The QUASAR respiratory body phantom along with patients breathing wave form and HexaPOD™ evo RT System was used to simulate the intra-fraction and inter-fraction motions. Dose measurements were done by applying the intra-fractional and inter-fractional motions in all the four treatment delivery techniques.Results: The maximum percentage deviation in a single field was -4.3%, 10.4%, and -12.2% for 3DCRT, D-IMRT and SS-IMRT deliveries, respectively. Similarly, the deviation for a single fraction was -1.51%, -1.88%, -2.22%, and -3.03% for 3DCRT, D-IMRT, SS-IMRT and VMAT deliveries, respectively. Conclusion: The impact of inter-fractional and intra-fractional uncertainties calculated as deviation between dynamic and static condition dose was large in some fractions, however average deviation calculated for thirty fractions was well within 0.5% in all the four techniques. Therefore, inter- and intra-fractional uncertainties could be concern in fewer fraction treatments such as stereotactic body radiation therapy, and should be used in conjunction with intra- and inter-fractional motion management techniques.

  19. Dosimetric evaluation of an automatic segmentation tool of pelvic structures from MRI images for prostate cancer radiotherapy; Evaluation dosimetrique d'un outil de delineation automatique des organes pelviens a partir d'images IRM pour la radiotherapie du cancer prostatique

    Energy Technology Data Exchange (ETDEWEB)

    Pasquier, D.; Lacornerie, T.; Lartigau, E. [Centre Oscar-Lambret, Dept. Universitaire de Radiotherapie, 59 - Lille (France); Pasquier, D. [Centre Galilee, Polyclinique de la Louviere, 59 - Lille (France); Pasquier, D.; Betrouni, N.; Vermandel, M.; Rousseau, J. [Lille-2 Univ., U703 Thiais, Inserm, Lab. de Biophysique EA 1049, Institut de Technologie Medicale, CHU de Lille, 59 (France)

    2008-09-15

    Purpose: An automatic segmentation tool of pelvic structures from MRI images for prostate cancer radiotherapy was developed and dosimetric evaluation of differences of delineation (automatic versus human) is presented here. Materials and methods: C.T.V. (clinical target volume), rectum and bladder were defined automatically and by a physician in 20 patients. Treatment plans based on 'automatic' volumes were transferred on 'manual' volumes and reciprocally. Dosimetric characteristics of P.T.V. (V.95, minimal, maximal and mean doses), rectum (V.50, V.70, maximal and mean doses) and bladder (V.70, maximal and mean doses) were compared. Results: Automatic delineation of C.T.V. did not significantly influence dosimetric characteristics of 'manual' P.T.V. (projected target volume). Rectal V-50 and V.70 were not significantly different; mean rectal dose is slightly superior (43.2 versus 44.4 Gy, p = 0.02, Student test). Bladder V.70 was significantly superior too (19.3 versus 21.6, p = 0.004). Organ-at-risk (O.A.R.) automatic delineation had little influence on their dosimetric characteristics; rectal V.70 was slightly underestimated (20 versus 18.5 Gy, p = 0.001). Conclusion: C.T.V. and O.A.R. automatic delineation had little influence on dosimetric characteristics. Software developments are ongoing to enable routine use and interobserver evaluation is needed. (authors)

  20. Dosimetric comparison of IMRT and modulated arc-therapy techniques in the treatment of cervical cancers; Comparaison dosimetrique des techniques de RCMI et d'arctherapie modulee dans le traitement des cancers du col uterin

    Energy Technology Data Exchange (ETDEWEB)

    Renard-Oldrini, S.; Charra-Brunaud, C.; Tournier-Rangeard, L.; Huger, S.; Marchesi, V.; Bouziz, D.; Peiffert, D. [Centre Alexis-Vautrin, Nancy (France)

    2011-10-15

    The authors report the dosimetric comparison of two techniques used for the treatment of cervical cancers: the intensity-modulated conformational radiotherapy (IMRT) with static beams and modulated arc-therapy with RapidArc. The treatment plans of 15 patients have been compared. The clinical target volume (CTV) comprises the gross target volume, the cervix, the upper third of the vagina, and ganglionary areas. The previsional target volume comprises the clinical target volume and a one centimetre margin. Organs at risk are rectum, bladder, intestine and bone marrow. Arc-therapy seems to provide a better sparing of intestine that IMRT, while maintaining a good coverage of the previsional target volume and decreasing treatment duration. Short communication

  1. The Dosimetric Consequences of Intensity Modulated Radiotherapy for Cervix Cancer: The Impact of Organ Motion, Deformation and Tumour Regression

    Science.gov (United States)

    Lim, Karen Siah Huey

    Hypothesis: In intensity modulated radiotherapy (IMRT) for cervix cancer, the dose received by the tumour target and surrounding normal tissues is significantly different to that indicated by a single static plan. Rationale: The optimal use of IMRT in cervix cancer requires a greater attention to clinical target volume (CTV) definition and tumour & normal organ motion to assure maximum tumour control with the fewest side effects. Research Aims: 1) Generate consensus CTV contouring guidelines for cervix cancer; 2) Evaluate intra-pelvic tumour and organ dynamics during radiotherapy; 3) Analyze the dose consequences of intra-pelvic organ dynamics on different radiotherapy strategies. Results: Consensus CTV definitions were generated using experts-in-the-field. Substantial changes in tumour volume and organ motion, resulted in significant reductions in accumulated dose to tumour targets and variability in accumulated dose to surrounding normal tissues. Significance: Formalized CTV definitions for cervix cancer is important in ensuring consistent standards of practice. Complex and unpredictable tumour and organ dynamics mandates daily soft-tissue image guidance if IMRT is used. To maximize the benefits of IMRT for cervix cancer, a strategy of adaptation is necessary.

  2. High Temperature VARTM with LaRC Polyimides

    Science.gov (United States)

    Cano, Roberto J.; Grimsley, Brian W.; Jensen, Brian J.; Kellen, Charles B.

    2004-01-01

    Recent work at NASA Langley Research Center (LaRC) has concentrated on developing new polyimide resin systems for advanced aerospace applications that can be processed without the use of an autoclave. Polyimide composites are very attractive for applications that require a high strength to weight ratio and thermal stability. Vacuum assisted resin transfer molding (VARTM) has shown potential to reduce the manufacturing cost of composite structures. In VARTM, the fibrous preform is infiltrated on a rigid tool surface contained beneath a flexible vacuum bag. Both resin injection and fiber compaction are achieved under pressures of 101.3 KPa or less. Recent studies have demonstrated the feasibility of the VARTM process for fabrication of void free structures utilizing epoxy resin systems with fiber volume fractions approaching 60%. In this work, the VARTM process has been extended to the fabrication of composite panels from polyimide systems developed at the Langley Research Center. This work has focused on processing LARC(trademark) PETI-8 (Langley Research Center Phenylethynyl Terminated Imide- 8), an aromatic polyimide based on 3,3',4,4' -biphenyltetracarboxylic dianhydride, a 50:50 molar ratio of 3,4'-oxydianiline and 1,3-bis(3-aminophenoxy)benzene, with 4-phenylethynylphthalic anhydride as the endcapping agent. Various molecular weight versions were investigated to determine their feasibility of being processed by VARTM at elevated temperatures. An injection temperature of approximately 280 C was required to achieve the necessary viscosity (VARTM pressures. Laminate quality and initial mechanical properties are presented for LARC(trademark) PETI-8 and 6k IM7 uniweave fabric.

  3. Quasi-Static Analysis of LaRC THUNDER Actuators

    Science.gov (United States)

    Campbell, Joel F.

    2007-01-01

    An analytic approach is developed to predict the shape and displacement with voltage in the quasi-static limit of LaRC Thunder Actuators. The problem is treated with classical lamination theory and Von Karman non-linear analysis. In the case of classical lamination theory exact analytic solutions are found. It is shown that classical lamination theory is insufficient to describe the physical situation for large actuators but is sufficient for very small actuators. Numerical results are presented for the non-linear analysis and compared with experimental measurements. Snap-through behavior, bifurcation, and stability are presented and discussed.

  4. Commercialization of LARC (TradeMark) -SI Polyimide Technology

    Science.gov (United States)

    Bryant, Robert G.

    2011-01-01

    LARC(TradeMark)-SI, Langley Research Center- Soluble Imide, was developed in 1992, with the first patent issuing in 1997, and then subsequent patents issued in 1998 and 2000. Currently, this polymer has been successfully licensed by NASA, and has generated revenues, at the time of this reporting, in excess of $1.4 million. The success of this particular polymer has been due to many factors and many lessons learned to the point that the invention, while important, is the least significant part in the commercialization of this material. Commercial LARC(TradeMark)-SI is a polyimide composed of two molar equivalents of dianhydrides: 4,4 -oxydiphthalic anhydride (ODPA), and 3,3 ,4,4 -biphenyltetracarboxylic dianhydride (BPDA) and 3,4 -oxydianiline (3,4 -ODA) as the diamine. The unique feature of this aromatic polyimide is that it remains soluble after solution imidization in high-boiling, polar aprotic solvents, even at solids contents of 50-percent by weight. However, once isolated and heated above its T(sub g) of 240 C, it becomes insoluble and exhibits high-temperature thermoplastic melt-flow behavior. With these unique structure property characteristics, it was thought this would be an advantage to have an aromatic polyimide that is both solution and melt processable in the imide form. This could potentially lead to lower cost production as it was not as equipment- or labor-intensive as other high-performance polyimide materials that either precipitate or are intractable. This unique combination of properties allowed patents with broad claim coverage and potential commercialization. After the U.S. Patent applications were filed, a Small Business Innovation Research (SBIR) contract was awarded to Imtec, Inc. to develop and supply the polyimide to NASA and the general public. Some examples of demonstration parts made with LARC(TradeMark)-SI ranged from aircraft wire and multilayer printed-circuit boards, to gears, composite panels, supported adhesive tape, composite

  5. SU-E-T-615: Investigation of the Dosimetric Impact of Tandem Loading in the Treatment of Cervical Cancer for HDR Brachytherapy Procedures

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, C; Patton, L; Nelson, K; Lin, B [Cancer Care Centers of South Texas, San Antonio, TX (United States)

    2014-06-01

    Purpose: To quantify the dosimetric impact of the tandem loading in the treatment of cervical cancer for HDR brachytherapy procedures. Methods: Ten patients were evaluated, each of whom received 5 fractions of treatment. Tandem and ovoid sets were inserted into the uterine cavity based on institutional protocols and procedures. Following insertion and stabilization, CT image sets of 1.5mm slice thickness were acquired and sent to the Oncentra V4.3 Treatment Planning System. Critical structures such as the CTV, bladder, rectum, sigmoid, and bowel were contoured and a fractional dose of 5.5Gy was prescribed to Point A for each patient. Six different treatment plans were created for each fraction using varying tandem weightings; from 0.5 to 1.4 times that of the ovoids. Surface dose evaluation of various ovoid diameters, 2.0-3.5cm, at the vaginal fornices was also investigated. Results: Critical structures were evaluated based on varying dose and volume constraints, in particular the 2.0 cc volume recommendation cited by the gynecological GEC-ESTRO working group. Based on dose volume histogram evaluation, a reduction of dose to the critical structures was most often discovered when the tandem weighting was increased. CTV coverage showed little change as the tandem weighting was varied. Ovoid surface dose decreased by 50-65% as the tandem weighting increased. Conclusion: The advantage of 3D planning with HDR brachytherapy is the dose optimization for each individual treatment plan. This investigation shows that by utilizing large tandem weightings, 1.4 times greater than the ovoid, one can still achieve adequate coverage of the CTV and relatively low doses to the critical structures. In some cases, one would still have to optimize further per individual case. In addition, the ovoid surface dose was greatly decreased when large tandem weighting was utilized; especially for small ovoid diameters.

  6. SU-F-BRB-14: Dosimetric Effects at Air- Tissue Boundary Due to Magnetic Field in MR-Guided IMRT/VMAT Delivery for Head and Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Prior, P; Chen, X; Schultz, C; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)

    2015-06-15

    Purpose: The advent of the MR-Linac enables real-time and high soft tissue contrast image guidance in radiation therapy (RT) delivery. Potential hot-spots at air-tissue interfaces, such as the sphenoid sinus, in RT for head and neck cancer (HNC), could potentially occur due to the electron return effect (ERE). In this study, we investigate the dosimetric effects of ERE on the dose distribution at air-tissues interfaces in HNC IMRT treatment planning. Methods: IMRT plans were generated based on planning CT’s acquired for HNC cases (nasopharynx, base of skull and paranasal sinus) using a research planning system (Monaco, v5.09.06, Elekta) employing Monte Carlo dose calculations with or without the presence of a transverse magnetic field (TMF). The dose in the air cavity was calculated in a 1 & 2 mm thick tissue layer, while the dose to the skin was calculated in a 1, 3 and 5 mm thick tissue layer. The maximum dose received in 1 cc volume, D1cc, were collected at different TMF strengths. Plan qualities generated with or without TMF or with increasing TMF were compared in terms of commonly-used dose-volume parameters (DVPs). Results: Variations in DVPs between plans with and without a TMF present were found to be within 5% of the planning CT. The presence of a TMF results in <5% changes in sinus air tissue interface. The largest skin dose differences with and without TMF were found within 1 mm of the skin surface Conclusion: The presence of a TMF results in practically insignificant changes in HNC IMRT plan quality, except for skin dose. Planning optimization with skin DV constraints could reduce the skin doses. This research was partially supported by Elekta Inc. (Crowley, U.K.)

  7. A Dosimetric Comparison between Conventional Fractionated and Hypofractionated Image-guided Radiation Therapies for Localized Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Ming Li

    2016-01-01

    Conclusions: To deliver the hypofractionated radiotherapy in prostate cancer, VMAT significantly increased PTV D95% dose and decreased the dose of radiation delivered to adjacent normal tissues comparing to 7-field, step-and-shoot IMRT. Daily online image-guidance and better management of bladder and rectum could make a more precise treatment delivery.

  8. A dosimetric evaluation of flattening filter-free volumetric modulated arc therapy for postoperative treatment of cervical cancer

    Institute of Scientific and Technical Information of China (English)

    Fuli Zhang; Bo Yao; Jun Hou; Heliang He; Jianping Chen; Huayong Jiang; Weidong Xu; Yadi Wang; Junmao Gao; Qingzhi Liu; Ping Wang; Na Lu; Diandian Chen

    2016-01-01

    Objective The aim of the study was to compare flattening filter-free (FFF) beams and conventional flat-tening filter (FF) beams in volumetric modulated arc therapy (VMAT) for cervical cancer after surgery, through a retrospective planning study. Methods VMAT plans of FFF beams and normal FF beams were designed for a cohort of 15 patients. The prescribed dose was 45 Gy to 1.8 Gy per fraction, and at least 95% of the planning target volume received this dose. Doses were computed with a commercial y available treatment planning system using a Monte Carlo (MC) algorithm. Plans were compared according to dose-volume histogram analysis in terms of planning target volume homogeneity and conformity indices (HI and CI), as wel as organs at risk (OAR) dose and volume parameters. Results FFF-VMAT was similar to FF-VMAT in terms of CI, but inferior to FF-VMAT considering HI. No statistical y dif erences were observed between FFF-VMAT and FF-VMAT in fol owing organ at risks includ-ing pelvic bone marrow, smal bowel, bladder, rectum, and normal tissue (NT). . Conclusion For patients with cervical cancer after hysterectomy, the FFF beam achieved target and OAR dose distribution similar to that of the FF beam. Reduction of beam-on time in cervical cancer is beneficial.

  9. Clinical and dosimetric evaluation of RapidArc versus standard sliding window IMRT in the treatment of head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Smet, Stephanie; Lambrecht, Maarten; Vanstraelen, Bianca; Nuyts, Sandra [University Hospitals Leuven, Department of Radiation Oncology, Leuven (Belgium)

    2014-08-29

    Several planning studies have already proven the substantial dosimetric advantages of RapidArc (RA) over standard intensity-modulated radiotherapy. We retrospectively compared RapidArc and standard sliding window IMRT (swIMRT) in locally advanced head and neck cancer, looking both at dosimetrics as well as toxicity and outcome. CT datasets of 78 patients treated with swIMRT and 79 patients treated with RA were included. To compare the resulting dose distributions, the dose-volume parameters were evaluated for the planning target volumes (PTVs), clinical target volumes (CTVs), and organs at risk (OARs), and the number of MU were calculated. Acute toxicity was assessed by the Common Toxicity Criteria version 3.0. PTV coverage with the 95 % isodose was slightly better for RA. Dose distribution has proven to be significantly more homogenous with RA and led to a reduction of 62 % in MU with better OAR sparing. As for toxicity, more grade 3 mucositis and dysphagia was observed for swIMRT, though we observed more grade 3 dermatitis for RA. In our retrospective analysis, RA had better target coverage and better sparing of the OAR. Overall, the grade of acute toxicity was lower for RA than for swIMRT for the same types of tumor locations, except for the grade of dermatitis. (orig.) [German] Mehrere Studien haben die dosimetrische Ueberlegenheit der RapidArc (RA) gegenueber der intensitaetsmodulierten Standard-Radiotherapie (IMRT) bereits gezeigt. In unserer Studie verglichen wir retrospektiv die RapidArc und die dynamische (''standard sliding window'') IMRT (swIMRT) bei lokal fortgeschrittenen Kopf-Hals-Karzinomen sowohl hinsichtlich dosimetrischer Daten als auchEffektivitaet und Toxizitaet. Die CT-Datenanalysen von 78 Patienten, die mit swIMRT behandelt wurden, und von 79 Patienten, welche RA erhalten hatten, wurden in die Studie aufgenommen. Um die darauf resultierenden applizierten Dosen vergleichen zu koennen, wurden die Dosis-Volumen-Parameter fuer

  10. SU-C-210-05: Evaluation of Robustness: Dosimetric Effects of Anatomical Changes During Fractionated Radiation Treatment of Pancreatic Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Horst, A van der; Houweling, A C; Bijveld, M M C; Visser, J; Bel, A [Academic Medical Center, Amsterdam, Noord-Holland (Netherlands)

    2015-06-15

    Purpose: Pancreatic tumors show large interfractional position variations. In addition, changes in gastrointestinal air volume and body contour take place during treatment. We aim to investigate the robustness of the clinical treatment plans by quantifying the dosimetric effects of these anatomical changes. Methods: Calculations were performed for up to now 3 pancreatic cancer patients who had intratumoral fiducials for daily CBCT-based positioning during their 3-week treatment. For each patient, deformable image registration of the planning CT was used to assign Hounsfield Units to each of the 13—15 CBCTs; air volumes and body contour were copied from CBCT. The clinical treatment plan was used (CTV-PTV margin = 10 mm; 36Gy; 10MV; 1 arc VMAT). Fraction dose distributions were calculated and accumulated. The V95% of the clinical target volume (CTV) and planning target volume (PTV) were analyzed, as well as the dose to stomach, duodenum and liver. Dose accumulation was done for patient positioning based on the fiducials (as clinically used) as well as for positioning based on bony anatomy. Results: For all three patients, the V95% of the CTV remained 100%, for both fiducial- and bony anatomy-based positioning. For fiducial-based positioning, dose to duodenum en stomach showed no discernable differences with planned dose. For bony anatomy-based positioning, the PTV V95% of the patient with the largest systematic difference in tumor position (patient 1) decreased to 85%; the liver Dmax increased from 33.5Gy (planned) to 35.5Gy. Conclusion: When using intratumoral fiducials, CTV dose coverage was only mildly affected by the daily anatomical changes. When using bony anatomy for patient positioning, we found a decline in PTV dose coverage due to the interfractional tumor position variations. Photon irradiation treatment plans for pancreatic tumors are robust to variations in body contour and gastrointestinal gas, but the use of fiducial-based daily position verification

  11. Dosimetric and geometric evaluation of the use of deformable image registration in adaptive intensity-modulated radiotherapy for head-and-neck cancer

    DEFF Research Database (Denmark)

    Eiland, R B; Maare, Christian; Sjöström, D

    2014-01-01

    The aim of this study was to carry out geometric and dosimetric evaluation of the usefulness of a deformable image registration algorithm utilized for adaptive head-and-neck intensity-modulated radiotherapy. Data consisted of seven patients, each with a planning CT (pCT), a rescanning CT (Re...... larger differences were observed for organs at risk. The deformed structures cannot fully replace manually delineated structures. Based on both geometrical and dosimetrical measures, there is a tendency for the dCT to overestimate the need for replanning, compared with the ReCT....

  12. D-IMRT verification with a 2D pixel ionization chamber: dosimetric and clinical results in head and neck cancer

    Science.gov (United States)

    Stasi, M.; Giordanengo, S.; Cirio, R.; Boriano, A.; Bourhaleb, F.; Cornelius, I.; Donetti, M.; Garelli, E.; Gomola, I.; Marchetto, F.; Porzio, M.; Sanz Freire, C. J.; Sardo, A.; Peroni, C.

    2005-10-01

    Dynamic intensity-modulated radiotherapy (D-IMRT) using the sliding-window technique is currently applied for selected treatments of head and neck cancer at Institute for Cancer Research and Treatment of Candiolo (Turin, Italy). In the present work, a PiXel-segmented ionization Chamber (PXC) has been used for the verification of 19 fields used for four different head and neck cancers. The device consists of a 32 × 32 matrix of 1024 parallel-plate ionization chambers arranged in a square of 24 × 24 cm2 area. Each chamber has 0.4 cm diameter and 0.55 cm height; a distance of 0.75 cm separates the centre of adjacent chambers. The sensitive volume of each single ionization chamber is 0.07 cm3. Each of the 1024 independent ionization chambers is read out with a custom microelectronics chip. The output factors in water obtained with the PXC at a depth of 10 cm were compared to other detectors and the maximum difference was 1.9% for field sizes down to 3 × 3 cm2. Beam profiles for different field dimensions were measured with the PXC and two other types of ionization chambers; the maximum distance to agreement (DTA) in the 20-80% penumbra region of a 3 × 3 cm2 field was 0.09 cm. The leaf speed of the multileaf collimator was varied between 0.07 and 2 cm s-1 and the detector response was constant to better than 0.6%. The behaviour of the PXC was measured while varying the dose rate between 0.21 and 1.21 Gy min-1; the mean difference was 0.50% and the maximum difference was 0.96%. Using fields obtained with an enhanced dynamic wedge and a staircase-like (step) IMRT field, the PXC has been tested for simple 1D modulated beams; comparison with film gave a maximum DTA of 0.12 cm. The PXC was then used to check four different IMRT plans for head and neck cancer treatment: cervical chordoma, parotid, ethmoid and skull base. In the comparison of the PXC versus film and PXC versus treatment planning system, the number of pixels with γ parameter <=1 was 97.7% and 97

  13. D-IMRT verification with a 2D pixel ionization chamber: dosimetric and clinical results in head and neck cancer

    Energy Technology Data Exchange (ETDEWEB)

    Stasi, M [Institute for Cancer Research and Treatment (IRCC), Candiolo and A.S.O. Ordine Maurizano, Torino (Italy); Giordanengo, S [Istituto Nazionale di Fisica Nucleare (INFN), Via P. Giuria 1, I-10125 Torino (Italy); Cirio, R [Istituto Nazionale di Fisica Nucleare (INFN), Via P. Giuria 1, I-10125 Torino (Italy)] [and others

    2005-10-07

    Dynamic intensity-modulated radiotherapy (D-IMRT) using the sliding-window technique is currently applied for selected treatments of head and neck cancer at Institute for Cancer Research and Treatment of Candiolo (Turin, Italy). In the present work, a PiXel-segmented ionization Chamber (PXC) has been used for the verification of 19 fields used for four different head and neck cancers. The device consists of a 32 x 32 matrix of 1024 parallel-plate ionization chambers arranged in a square of 24 x 24 cm{sup 2} area. Each chamber has 0.4 cm diameter and 0.55 cm height; a distance of 0.75 cm separates the centre of adjacent chambers. The sensitive volume of each single ionization chamber is 0.07 cm{sup 3}. Each of the 1024 independent ionization chambers is read out with a custom microelectronics chip. The output factors in water obtained with the PXC at a depth of 10 cm were compared to other detectors and the maximum difference was 1.9% for field sizes down to 3 x 3 cm{sup 2}. Beam profiles for different field dimensions were measured with the PXC and two other types of ionization chambers; the maximum distance to agreement (DTA) in the 20-80% penumbra region of a 3 x 3 cm{sup 2} field was 0.09 cm. The leaf speed of the multileaf collimator was varied between 0.07 and 2 cm s{sup -1} and the detector response was constant to better than 0.6%. The behaviour of the PXC was measured while varying the dose rate between 0.21 and 1.21 Gy min{sup -1}; the mean difference was 0.50% and the maximum difference was 0.96%. Using fields obtained with an enhanced dynamic wedge and a staircase-like (step) IMRT field, the PXC has been tested for simple 1D modulated beams; comparison with film gave a maximum DTA of 0.12 cm. The PXC was then used to check four different IMRT plans for head and neck cancer treatment: cervical chordoma, parotid, ethmoid and skull base. In the comparison of the PXC versus film and PXC versus treatment planning system, the number of pixels with {gamma

  14. Dosimetric comparison of carbon ion and X-ray radiotherapy for Stage IIIA non–small cell lung cancer

    Science.gov (United States)

    Kubo, Nobuteru; Saitoh, Jun-ichi; Shimada, Hirofumi; Shirai, Katsuyuki; Kawamura, Hidemasa; Ohno, Tatsuya; Nakano, Takashi

    2016-01-01

    The present study compared the dose–volume histograms of patients with Stage IIIA non–small cell lung cancer (NSCLC) treated with carbon ion radiotherapy with those of patients treated with X-ray radiotherapy. Patients with Stage IIIA NSCLC (n = 10 patients for each approach) were enrolled. Both radiotherapy plans were calculated with the same targets and organs at risk on the same CT. The treatment plan for the prophylactic lymph node and primary tumor (PTV1) delivered 40 Gy for X-ray radiotherapy and 40 Gy (relative biological effectiveness; RBE) for carbon ion radiotherapy. The total doses for the primary tumor and clinically positive lymph nodes (PTV2) were 60 Gy for X-ray radiotherapy and 60 Gy (RBE) for carbon ion radiotherapy. The homogeneity indexes for PTV1 and PTV2 were superior for carbon ion radiotherapy in comparison with X-ray radiotherapy (PTV1, 0.57 vs 0.65, P = 0.009; PTV2, 0.07 vs 0.16, P = 0.005). The normal lung mean dose, V5, V10 and V20 for carbon ion radiotherapy were 7.7 Gy (RBE), 21.4%, 19.7% and 17.0%, respectively, whereas the corresponding doses for X-ray radiotherapy were 11.9 Gy, 34.9%, 26.6% and 20.8%, respectively. Maximum spinal cord dose, esophageal maximum dose and V50, and bone V10, V30 and V50 were lower with carbon ion radiotherapy than with X-ray radiotherapy. The present study indicates that carbon ion radiotherapy provides a more homogeneous target dose and a lower dose to organs at risk than X-ray radiotherapy for Stage IIIA non–small cell lung cancer. PMID:27242341

  15. Dosimetric comparison of volumetric modulated Arc therapy, step-and-shoot, and sliding window IMRT for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Schnell, Erich; De La Fuente Herman, Tania; Young, Julie; Hildebrand, Kim; Algan, Ozer; Syzek, Elizabeth; Herman, Terence; Ahmad, Salahuddin [Department of Radiation Oncology, University of Oklahoma Health Sciences Center 800 N.E. 10th St., OKCC L100, Oklahoma City, OK 73104 (United States)

    2012-10-23

    This study aims to evaluate treatment plans generated by Step-and-Shoot (SS), Sliding Window (SW) and Volumetric Modulated Arc Therapy (VMAT) in order to assess the differences in dose volume histograms of planning target volume (PTV) and organs at risk (OAR), conformity indices, radiobiological evaluations, and plan quality for prostate cancer cases. Six prostate cancer patients treated in our center were selected for this retrospective study. Treatment plans were generated with Eclipse version 8.9 using 10 MV photon beams. For VMAT, Varian Rapid Arc with 1 or 2 arcs, and for SS and SW IMRT, 7-9 fields were used. Each plan had three PTVs with prescription doses of 81, 59.4, and 45 Gy to prostate, to prostate and lymph nodes, and to pelvis, respectively. Doses to PTV and OAR and the conformal indices (COIN) were compared among three techniques. The equivalent uniform dose (EUD), tumor control probability (TCP) and normal tissue complication probability (NTCP) were calculated and compared. The mean doses to the PTV prostate on average were 83 Gy and the percent differences of mean dose among all techniques were below 0.28. For bladder and rectum, the percent differences of mean dose among all techniques were below 2.2. The COIN did not favour any particular delivery method over the other. The TCP was higher with SS and SW for four patients and higher with VMAT for two patients. The NTCP for the rectum was the lowest with VMAT in five out of the six patients. The results show similar target coverage in general.

  16. Dosimetric Predictors of Radiation-Induced Vaginal Stenosis After Pelvic Radiation Therapy for Rectal and Anal Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Son, Christina H.; Law, Ethel [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Oh, Jung Hun; Apte, Aditya P. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Yang, T. Jonathan [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Riedel, Elyn [Department of Biostatistics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Wu, Abraham J. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Deasy, Joseph O. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Goodman, Karyn A., E-mail: goodmank@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2015-07-01

    Purpose: Although vaginal stenosis (VS) is a recognized toxicity in women who receive pelvic radiation therapy (RT), the relationship between RT dose and the volume and extent of toxicity has not been analyzed. We modeled this relationship to identify predictors of VS. Methods and Materials: We evaluated 54 women, aged 29 to 78 years, who underwent pelvic RT for rectal or anal cancer during 2008 to 2011 and were enrolled in a prospective study evaluating vaginal dilator use. Maximum dilator size was measured before RT (baseline) and 1 month and 12 months after RT. Dilator use was initiated at 1 month. The difference (D) in dilator size before and after RT was recorded. Those with D ≤−1 were classified as having VS (n=35); those with D ≥0 were classified as having no VS (n=19 at 1 month). Dose-volume parameters were extracted, and the generalized equivalent uniform dose (gEUD) was used to build a predictive model. Results: The mean vaginal doses were 50.0 Gy and 36.8 Gy for anal and rectal cancer patients, respectively. One month after RT, a gEUD model using a wide range of a values suggests that sparing of vaginal volume to a low dose may be important. When gEUD (a = −1) was <35 Gy and the mean vaginal dose was <43 Gy, severe VS was reduced (P=.02). A 1-year analysis suggests increasingly negative D values with increasing mean dose. However, patients with compliance <40% were more likely to have toxicity. Conclusions: Vaginal stenosis is influenced by multiple RT dose-volume characteristics. Mean dose and gEUD constraints together may reduce the risk of severe VS. Patients receiving higher mean vaginal doses should have greater compliance with dilator therapy to minimize risk of toxicity. Further validation with independent datasets is needed.

  17. Radiotherapy of internal mammary lymph nodes in breast cancer. Principle considerations on the basis of dosimetric data

    Energy Technology Data Exchange (ETDEWEB)

    Sautter-Bihl, M.L.; Hueltenschmidt, B.; Melcher, U. [Staedtisches Klinikum Karlsruhe (Germany). Dept. of Radiotherapy; Ulmer, H.U. [Dept. of Gynecology, Staedtisches Klinikum Karlsruhe (Germany)

    2002-01-01

    Background: Radiotherapy of internal mammary lymph nodes (IMN) in breast cancer is discussed controversially due to its potential toxicity and debatable efficacy. Aim of the present study was to assess the cardiac and lung dose in 3-D planned radiotherapy and to discuss these results with regard to arguments pro and contra IMN irradiation. Patients and Methods: 32 patients underwent 3-D planning (Helax TMS) for irradiation of breast and IMN in three different techniques either using separate IMN fields (A, B) or a wide tangent (C). For each technique the respective doses to the heart (including the base of the aorta and the ostium of the coronary arteries) and lung were analyzed in dose volume histograms. Results: The mean dose to the heart (left side irradiation) was 6.4 Gy (A), 8.1 Gy (B) and 3.8 Gy (C). The mean dose to the lung was 11.7 Gy (A), 15.4 Gy (B) and 10.2 Gy (C). The 10-Gy isodose comprised 19.5% (A), 32.9% (B) and 5.6% (C) of the heart (left breast). The respective values for the 20-Gy isodose were 7.8, 11.5 and 4.4%. The irradiated volumes of the lung were 37.7% (A), 52.7% (B) and 20% (C) in the 10-Gy isodose. The 20-Gy isodose comprised 16.7% (A), 28.3% (B) and 17.8% (C). Conclusion: Whether radiotherapy of the IMN may improve treatment results in breast cancer is currently unresolved. However, the present data indicate that relevant cardiovascular side effects are unlikely to occur. Thus, the indication should be considered on the basis of individual risk factors. (orig.) [German] Hintergrund: Die Strahlentherapie der Mammaria-interna-Lymphknoten (IMN) wird kontrovers diskutiert, da ihre potenzielle Toxizitaet gefuerchtet und ihre Wirksamkeit angezweifelt werden. Ziel der vorliegenden Studie war, die Herz- und Lungendosis bei 3-D-geplanter Strahlentherapie zu ermitteln und anhand dieser Resultate die Argumente fuer und wider eine IMN-Bestrahlung zu diskutieren. Patienten und Methoden: Bei 32 Patientinnen erfolgte die 3-D-Planung (Helax TMS) zur

  18. Dosimetric study of volumetric arc modulation with RapidArc and intensity-modulated radiotherapy in patients with cervical cancer and comparison with 3-dimensional conformal technique for definitive radiotherapy in patients with cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Guy, Jean-Baptiste [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Falk, Alexander T. [Department of Radiation Oncology, Centre Antoine Lacassagne, Nice (France); Auberdiac, Pierre [Department of Radiation Oncology, Clinique Claude Bernard, Albi (France); Cartier, Lysian; Vallard, Alexis [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Ollier, Edouard [Department of Pharmacology-Toxicology, Centre Hospitalier Universitaire de Saint-Etienne, Saint-Priest en Jarez (France); Trone, Jane-Chloé; Khodri, Moustapha [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France); Chargari, Cyrus [Department of Radiation Oncology, Hôpital d’instruction de Armées du Val-de-Grâce, Paris (France); Magné, Nicolas, E-mail: nicolas.magne@icloire.fr [Department of Radiation Oncology, Institut de Cancérologie de la Loire Lucien Neuwirth, Saint-Priest en Jarez (France)

    2016-04-01

    Introduction: For patients with cervical cancer, intensity-modulated radiation therapy (IMRT) improves target coverage and allows dose escalation while reducing the radiation dose to organs at risk (OARs). In this study, we compared dosimetric parameters among 3-dimensional conformal radiotherapy (3D-CRT), “step-and-shoot” IMRT, and volumetric intensity-modulated arc radiotherapy (VMAT) in a series of patients with cervical cancer receiving definitive radiotherapy. Computed tomography (CT) scans of 10 patients with histologically proven cervical cancer treated with definitive radiation therapy (RT) from December 2008 to March 2010 at our department were selected for this study. The gross tumor volume (GTV) and clinical target volume (CTV) were delineated following the guidelines of the Gyn IMRT consortium that included cervix, uterus, parametrial tissues, and the pelvic nodes including presacral. The median age was 57 years (range: 30 to 85 years). All 10 patients had squamous cell carcinoma with Federation of Gynecology and Obstetrics (FIGO) stage IB-IIIB. All patients were treated by VMAT. OAR doses were significantly reduced for plans with intensity-modulated technique compared with 3D-CRT except for the dose to the vagina. Between the 2 intensity-modulated techniques, significant difference was observed for the mean dose to the small intestine, to the benefit of VMAT (p < 0.001). There was no improvement in terms of OARs sparing for VMAT although there was a tendency for a slightly decreased average dose to the rectum: − 0.65 Gy but not significant (p = 0.07). The intensity modulation techniques have many advantages in terms of quality indexes, and particularly OAR sparing, compared with 3D-CRT. Following the ongoing technologic developments in modern radiotherapy, it is essential to evaluate the intensity-modulated techniques on prospective studies of a larger scale.

  19. Quality control of dosimetric systems using thermoluminescent crystals; Control de calidad de un sistema de planeacion dosimetrico utilizando cristales termoluminiscentes y su aplicacion en tratamientos de pacientes con cancer de prostata

    Energy Technology Data Exchange (ETDEWEB)

    Mahecha, L.; Plazas, M. C.; Machado, M.; Perea, M. D.

    2006-07-01

    To achieve an optimal tumoral control to prostate cancer in early and locally advanced stages, it is necessary to increase the dose with a low mobility probability at the vesicle an rectal level. This is achieved through conformal radiotherapy. The Instituto Nacional de Cancerologia uses this technique, but two questions arise from the medical-physicists and medical radio-oncologist: In accordance with clinical protocols, the conformal radiotherapy delivers a low dose to the adjacent healthy tissues. What experimental method exists that can prove with certainly the veracity of this affirmation?. And, Do the dosimetric simulation system calculate suitable the dose for each tissues?. Through thermoluminescent dosimetry and the use of a physical simulator,we measured the absorbed dose at the target volume and the adjacent tissues using conformal and conventional radiotherapy. We proved that organs such as the rectum and bladder, receiver a minor dose in conformal radiotherapy, hence reducing their mobility probability. In addition, the readings from the thermoluminescent dosimeters and the doses calculated by the ECLIPSE dosimetric system were compared, concluding that the patient's prescribed dose is effectively delivered as recommended by the quality control program in radiotherapy. (Author)

  20. Dosimetric calculation of I-131 activity for the treatment to patients having differentiated thyroid cancer. Benefits and limitations; Calculo dosimetrico de la actividad de I-131 para tratamiento de pacientes con cancer diferenciado de tiroides (CADT). Beneficios y limitaciones

    Energy Technology Data Exchange (ETDEWEB)

    Cabrejas, R. C.; Chebel, G. M.; Fadel, A. M.; Rojo, A. M.; Deluca, G.; Degross, O. J.; Valdivieso, C. M.; Carbejas, M. L.

    2006-07-01

    Maximum safe activity calculation, that has to be administered for treatment to patients having Differentiated Thyroid Cancer (CADT). No important side effects should be produced. Post treatment evolution was analysed. 23 Dosimetric studies were performed determining blood and whole body uptake curves (CE)during 5 days. Using the MIRDOSE software, the maximum safe activity in the whole body (CE)was calculated. The retained activity in the body (AR), 48 hs. post tracer dose. Should have been less than 2.96 GBq so as to avoid lung fibrosis. 17 patients that received activities<11.1 GBq, had no side effects. Three patients presents special situations: high AR, users in the mouth, and plaque to and leucopenia. This methodology has benefits because AT can be estimated. This was possible for 85% of the patients. When AR was high at 48 hr, AT was diminished to avoid pulmonary lesions. Tumor absorbed dose estimation, will allow the administration of AT>11.1 GBq in the future. (Author)

  1. Dosimetric comparison of intensity modulated radiotherapy isocentric field plans and field in field (FIF) forward plans in the treatment of breast cancer.

    Science.gov (United States)

    Al-Rahbi, Zakiya Salem; Al Mandhari, Zahid; Ravichandran, Ramamoorthy; Al-Kindi, Fatma; Davis, Cheriyathmanjiyil Anthony; Bhasi, Saju; Satyapal, Namrata; Rajan, Balakrishnan

    2013-01-01

    The present study is aimed at comparing the planning and delivery efficiency between three-dimensional conformal radiotherapy (3D-CRT), field-in-field, forward planned, intensity modulated radiotherapy (FIF-FP-IMRT), and inverse planned intensity modulated radiotherapy (IP-IMRT). Treatment plans of 20 patients with left-sided breast cancer, 10 post-mastectomy treated to a prescribed dose of 45 Gy to the chest wall in 20 fractions, and 10 post-breast-conserving surgery to a prescribed dose of 50 Gy to the whole breast in 25 fractions, with 3D-CRT were selected. The FiF-FP-IMRT plans were created by combining two open fields with three to four segments in two tangential beam directions. Eight different beam directions were chosen to create IP-IMRT plans and were inversely optimized. The homogeneity of dose to planning target volume (PTV) and the dose delivered to heart and contralateral breast were compared among the techniques in all the 20 patients. All the three radiotherapy techniques achieved comparable radiation dose delivery to PTV-95% of the prescribed dose covering > 95% of the breast PTV. The mean volume of PTV receiving 105% (V105) of the prescribed dose was 1.7% (range 0-6.8%) for IP-IMRT, 1.9% for FP-IMRT, and 3.7% for 3D-CRT. The homogeneity and conformity indices (HI and CI) were similar for 3D-CRT and FP-IMRT, whereas the IP-IMRT plans had better conformity index at the cost of less homogeneity. The 3D-CRT and FiF-FP-IMRT plans achieved similar sparing of critical organs. The low-dose volumes (V5Gy) in the heart and lungs were larger in IP-IMRT than in the other techniques. The value of the mean dose to the ipsilateral lung was higher for IP-IMRT than the values for with FiF-FP-IMRT and 3D-CRT. In the current study, the relative volume of contralateral breast receiving low doses (0.01, 0.6, 1, and 2Gy) was significantly lower for the FiF-FP-IMRT and 3D-CRT plans than for the IP-IMRT plan. Compared with 3D-CRT and IP-IMRT, FiF-FP-IMRT proved to be a

  2. Dosimetric consequences of tumor volume changes after kilovoltage cone-beam computed tomography for non-operative lung cancer during adaptive intensity-modulated radiotherapy or fractionated stereotactic radiotherapy

    Institute of Scientific and Technical Information of China (English)

    Jian Hu; Ximing Xu; Guangjin Yuan; Wei Ge; Liming Xu; Aihua Zhang; Junjian Deng

    2015-01-01

    Objective The aim of this study was to investigate tumor volume changes with kilovoltage cone-beam computed tomography (kV-CBCT) and their dosimetric consequences for non-operative lung cancer during intensity-modulated radiotherapy (IMRT) or fractionated stereotactic radiotherapy. Methods Eighteen patients with non-operative lung cancer who received IMRT consisting of 1.8-2.2 Gy/fraction and five fractions per week or stereotactic radiotherapy with 5-8 Gy/fraction and three fractions a week were studied. kV-CBCT was performed once per week during IMRT and at every fraction during stereotactic radiotherapy. The gross tumor volume (GTV) was contoured on the kV-CBCT images, and adaptive treatment plans were created using merged kV-CBCT and primary planning computed tomogra-phy image sets. Tumor volume changes and dosimetric parameters, including the minimum dose to 95%(D95) or 1% (D1) of the planning target volume (PTV), mean lung dose (MLD), and volume of lung tissue that received more than 5 (V5), 10 (V10), 20 (V20), and 30 (V30) Gy were retrospectively analyzed. Results The average maximum change in GTV observed during IMRT or fractionated stereotactic radio-therapy was -25.85% (range, -13.09% --56.76%). The D95 and D1 of PTV for the adaptive treatment plans in all patients were not significantly different from those for the initial or former adaptive treatment plans. In patients with tumor volume changes of >20% in the third or fourth week of treatment during IMRT, adap-tive treatment plans offered clinically meaningful decreases in MLD and V5, V10, V20, and V30; however, in patients with tumor volume changes of 20% in the third or fourth week of treatment.

  3. Dosimetric comparison in a cancer of the Cervix with different therapeutic modalities; Comparacion dosimetrica en un cancer de Cervix con distintas modalidades terapeuticas

    Energy Technology Data Exchange (ETDEWEB)

    Alonso Iracheta, L.; Casa de Julian, M. A. de la; Samper Ots, P.; Penas Cabrera, M. D. de las; Jimenez Gonzalez, J. M.

    2013-07-01

    Cervical cancer is usually treated with radiotherapy composed of 3D (RC3D) and supine position, and is usually not usually outline the small intestine in cases of exclusively pelvic irradiation. In our Center we wanted to check what dose receives the small intestine in these cases and if the positioning of the patient or used irradiation technique influence the distribution of the histogram dose-volume. (Author)

  4. SU-E-T-596: Axillary Nodes Radiotherapy Boost Field Dosimetric Impact Study: Oblique Field and Field Optimization in 3D Conventional Breast Cancer Radiation Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Su, M [Mount Sinai School of Medicine, Elmhurst, NY (United States); Sura, S

    2014-06-01

    Purpose: To evaluate dosimetric impact of two axillary nodes (AX) boost techniques: (1) posterior-oblique optimized field boost (POB), (2) traditional posterior-anterior boost (PAB) with field optimization (O-PAB), for a postmastectomy breast patient with positive axillary lymph nodes. Methods: Five patients, 3 left and 2 right chest walls, were included in this study. All patients were simulated in 5mm CT slice thickness. Supraclavicular (SC) and level I/II/III AX were contoured based on the RTOG atlas guideline. Five treatment plans, (1) tangential chest wall, (2) oblique SC including AX, (3) PAB, O-PAB and POB, were created for each patient. Three plan sums (PS) were generated by sum one of (3) plan with plan (1) and (2). The field optimization was done through PS dose distribution, which included a field adjustment, a fractional dose, a calculation location and a gantry angle selection for POB. A dosimetric impact was evaluated by comparing a SC and AX coverage, a PS maximum dose, an irradiated area percentage volume received dose over 105% prescription dose (V105), an ipsi-laterial mean lung dose (MLD), an ipsi-laterial mean humeral head dose (MHHD), a mean heart dose (MHD) (for left case only) and their DVH amount these three technique. Results: O-PAB, POB and PAB dosimetric results showed that there was no significant different on SC and AX coverage (p>0.43) and MHD (p>0.16). The benefit of sparing lung irradiation from PAB to O-PAB to POB was significant (p<0.004). PAB showed a highest PS maximum dose (p<0.005), V105 (p<0.023) and MLD (compared with OPAB, p=0.055). MHHD showed very sensitive to the patient arm positioning and anatomy. O-PAB convinced a lower MHHD than PAB (p=0.03). Conclusion: 3D CT contouring plays main role in accuracy radiotherapy. Dosimetric advantage of POB and O-PAB was observed for a better normal tissue irradiation sparing.

  5. Dosimetric Predictors of Duodenal Toxicity After Intensity Modulated Radiation Therapy for Treatment of the Para-aortic Nodes in Gynecologic Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Jonathan [Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, Florida (United States); Sulman, Erik P.; Jhingran, Anuja [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Tucker, Susan L. [Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Rauch, Gaiane M. [Department of Radiology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Eifel, Patricia J. [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Klopp, Ann H., E-mail: aklopp@mdanderson.org [Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2014-02-01

    Purpose: To determine the incidence of duodenal toxicity in patients receiving intensity modulated radiation therapy (IMRT) for treatment of para-aortic nodes and to identify dosimetric parameters predictive of late duodenal toxicity. Methods and Materials: We identified 105 eligible patients with gynecologic malignancies who were treated with IMRT for gross metastatic disease in the para-aortic nodes from January 1, 2005, through December 31, 2009. Patients were treated to a nodal clinical target volume to 45 to 50.4 Gy with a boost to 60 to 66 Gy. The duodenum was contoured, and dosimetric data were exported for analysis. Duodenal toxicity was scored according to Radiation Therapy Oncology Group criteria. Univariate Cox proportional hazards analysis and recursive partitioning analysis were used to determine associations between dosimetric variables and time to toxicity and to identify the optimal threshold that separated patients according to risk of toxicity. Results: Nine of the 105 patients experienced grade 2 to grade 5 duodenal toxicity, confirmed by endoscopy in all cases. The 3-year actuarial rate of any duodenal toxicity was 11.7%. A larger volume of the duodenum receiving 55 Gy (V55) was associated with higher rates of duodenal toxicity. The 3-year actuarial rates of duodenal toxicity with V55 above and below 15 cm{sup 3} were 48.6% and 7.4%, respectively (P<.01). In Cox univariate analysis of dosimetric variables, V55 was associated with duodenal toxicity (P=.029). In recursive partitioning analysis, V55 less than 13.94% segregated all patients with duodenal toxicity. Conclusions: Dose-escalated IMRT can safely and effectively treat para-aortic nodal disease in gynecologic malignancies, provided that care is taken to limit the dose to the duodenum to reduce the risk of late duodenal toxicity. Limiting V55 to below 15 cm{sup 3} may reduce the risk of duodenal complications. In cases where the treatment cannot be delivered within these constraints

  6. Standardized Index of Shape (SIS): a quantitative DCE-MRI parameter to discriminate responders by non-responders after neoadjuvant therapy in LARC

    Energy Technology Data Exchange (ETDEWEB)

    Petrillo, Antonella; Fusco, Roberta; Petrillo, Mario; Granata, Vincenza [Istituto Nazionale Tumori Fondazione Giovanni Pascale - IRCCS, Naples (Italy). Div. of Radiology; Sansone, Mario [Naples Univ. ' ' Federico II' ' (Italy). Dept. of Biomedical, Electronics and Telecommunications Engineering; Avallone, Antonio [Istituto Nazionale Tumori Fondazione Giovanni Pascale - IRCCS, Naples (Italy). Div. of Gastrointestinal Medical Oncology; Delrio, Paolo [Istituto Nazionale Tumori Fondazione Giovanni Pascale - IRCCS, Naples (Italy). Div. of Gastrointestinal surgical Oncology; Pecori, Biagio [Istituto Nazionale Tumori Fondazione Giovanni Pascale - IRCCS, Naples (Italy). Div. of Radiotherapy; Tatangelo, Fabiana [Istituto Nazionale Tumori Fondazione Giovanni Pascale - IRCCS, Naples (Italy). Div. of Diagnostic Pathology; Ciliberto, Gennaro [Istituto Nazionale Tumori Fondazione Giovanni Pascale - IRCCS, Naples (Italy)

    2015-07-15

    To investigate the potential of DCE-MRI to discriminate responders from non-responders after neoadjuvant chemo-radiotherapy (CRT) for locally advanced rectal cancer (LARC). We investigated several shape parameters for the time-intensity curve (TIC) in order to identify the best combination of parameters between two linear parameter classifiers. Seventy-four consecutive patients with LARC were enrolled in a prospective study approved by our ethics committee. Each patient gave written informed consent. After surgery, pathological TNM and tumour regression grade (TRG) were estimated. DCE-MRI semi-quantitative analysis (sqMRI) was performed to identify the best parameter or parameter combination to discriminate responders from non-responders in response monitoring to CRT. Percentage changes of TIC shape descriptors from the baseline to the presurgical scan were assessed and correlated with TRG. Receiver operating characteristic analysis and linear classifier were applied. Forty-six patients (62.2 %) were classified as responders, while 28 subjects (37.8 %) were considered as non-responders. sqMRI reached a sensitivity of 93.5 % and a specificity of 82.1 % combining the percentage change in Maximum Signal Difference (ΔMSD) and Wash-out Slope (ΔWOS), the Standardized Index of Shape (SIS). SIS obtains the best result in discriminating responders from non-responders after CRT in LARC, with a cut-off value of -3.0 %. (orig.)

  7. Dosimetric Comparison Between VMAT and IMRT for Liver Cancer%基于肝癌的VMAT与IMRT放疗计划的剂量学对比研究

    Institute of Scientific and Technical Information of China (English)

    孙长江; 李军; 张西志; 张先稳; 桂龙刚; 陈雪梅

    2015-01-01

    目的:比较分析肝癌旋转容积调强放疗( VMAT)计划与固定野调强放疗( IMRT)计划靶区及其周围危机器官的剂量学差异。方法选择36例肝癌患者的CT图像数据,分别设计VMAT计划、IMRT计划,比较两者的靶区剂量分布、危及器官受量、正常组织受量、机器跳数及治疗时间等。结果 VMAT计划的靶区剂量最大值比IMRT计划低( Z=2.090,P<0.05);VMAT计划的90%的处方剂量的适形指数比IMRT计划小(Z=2.809,P<0.05);VMAT计划的正常肝组织的V30低于IMRT计划(Z=2.395,P<0.05);VMAT计划的正常肾脏组织的V20低于 IMRT计划(Z=2.201,P<0.05);VMAT计划机器跳数是 IMRT计划的<40%,治疗时间低于IMRT计划的50%。结论2种治疗计划在剂量学上均能满足临床要求,并且剂量分布基本一致,VMAT计划的适形指数比IMRT好,危及器官剂量比IMRT计划略有降低,正常组织的低剂量区VMAT计划与IMRT相比有先高后低的趋势,并且机器跳数少,治疗时间短,更值得临床推广应用。%Objective To compare the dosimetric differences of the target volume and the surrounding organ at risk between volumetric modulated arc radiotherapy( VMAT)and fixed field intensity-modulated radiation therapy ( IMRT)plans for liver cancer. Methods The CT image data of 36 patients with liver cancer were observed,the VMAT plan and the IMRT plan were designed,the target dose distribution of the two plans,organs at risk affected by quantity ,normal tissue by volume ,the number of machine unit and treatment time of the two plans were compared .Results The maximum value in the target region of the VMAT plan was lower than that of the IMRT plan( Z=2. 090,P<0. 05);the conformal index of 90% of prescription dose in the VMAT plan was smaller than that in the IMRT plan(Z=2. 809,P<0. 05);the V30 of liver in the VMAT plan was lower than that in the IMRT plan(Z=2. 395,P<0. 05);the V20 of kidney in the

  8. [Dosimetric evaluation of conformal radiotherapy: conformity factor].

    Science.gov (United States)

    Oozeer, R; Chauvet, B; Garcia, R; Berger, C; Felix-Faure, C; Reboul, F

    2000-01-01

    The aim of three-dimensional conformal therapy (3DCRT) is to treat the Planning Target Volume (PTV) to the prescribed dose while reducing doses to normal tissues and critical structures, in order to increase local control and reduce toxicity. The evaluation tools used for optimizing treatment techniques are three-dimensional visualization of dose distributions, dose-volume histograms, tumor control probabilities (TCP) and normal tissue complication probabilities (NTCP). These tools, however, do not fully quantify the conformity of dose distributions to the PTV. Specific tools were introduced to measure this conformity for a given dose level. We have extended those definitions to different dose levels, using a conformity index (CI). CI is based on the relative volumes of PTV and outside the PTV receiving more than a given dose. This parameter has been evaluated by a clinical study including 82 patients treated for lung cancer and 82 patients treated for prostate cancer. The CI was low for lung dosimetric studies (0.35 at the prescribed dose 66 Gy) due to build-up around the GTV and to spinal cord sparing. For prostate dosimetric studies, the CI was higher (0.57 at the prescribed dose 70 Gy). The CI has been used to compare treatment plans for lung 3DCRT (2 vs 3 beams) and prostate 3DCRT (4 vs 7 beams). The variation of CI with dose can be used to optimize dose prescription.

  9. Automatically gated image-guided breath-hold IMRT is a fast, precise, and dosimetrically robust treatment for lung cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Simeonova-Chergou, Anna; Jahnke, Anika; Siebenlist, Kerstin; Stieler, Florian; Mai, Sabine; Boda-Heggemann, Judit; Wenz, Frederik; Lohr, Frank; Jahnke, Lennart [University Medical Center Mannheim, University of Heidelberg, Department of Radiotherapy and Oncology, Mannheim (Germany)

    2016-03-15

    High-dose radiotherapy of lung cancer is challenging. Tumors may move by up to 2 cm in craniocaudal and anteroposterior directions as a function of breathing cycle. Tumor displacement increases with treatment time, which consequentially increases the treatment uncertainty. This study analyzed whether automatically gated cone-beam-CT (CBCT)-controlled intensity modulated fast deep inspiration breath hold (DIBH) stereotactic body radiation therapy (SBRT) in flattening filter free (FFF) technique and normofractionated lung DIBH intensity-modulated radiotherapy (IMRT)/volumetric-modulated arc therapy (VMAT) treatments delivered with a flattening filter can be applied with sufficient accuracy within a clinically acceptable timeslot. Plans of 34 patients with lung tumors were analyzed. Of these patients, 17 received computer-controlled fast DIBH SBRT with a dose of 60 Gy (5 fractions of 12 Gy or 12 fractions of 5 Gy) in an FFF VMAT technique (FFF-SBRT) every other day and 17 received conventional VMAT with a flattening filter (conv-VMAT) and 2-Gy daily fractional doses (cumulative dose 50-70 Gy). FFF-SBRT plans required more monitor units (MU) than conv-VMAT plans (2956.6 ± 885.3 MU for 12 Gy/fraction and 1148.7 ± 289.2 MU for 5 Gy/fraction vs. 608.4 ± 157.5 MU for 2 Gy/fraction). Total treatment and net beam-on times were shorter for FFF-SBRT plans than conv-VMAT plans (268.0 ± 74.4 s vs. 330.2 ± 93.6 s and 85.8 ± 25.3 s vs. 117.2 ± 29.6 s, respectively). Total slot time was 13.0 min for FFF-SBRT and 14.0 min for conv-VMAT. All modalities could be delivered accurately despite multiple beam-on/-off cycles and were robust against multiple interruptions. Automatically gated CBCT-controlled fast DIBH SBRT in VMAT FFF technique and normofractionated lung DIBH VMAT can be applied with a low number of breath-holds in a short timeslot, with excellent dosimetric accuracy. In clinical routine, these approaches combine optimally reduced lung tissue irradiation with maximal

  10. SU-E-T-310: Dosimetric Comparison of Tandem and Ovoid (TO) Vs. Tandem and Ring (TR) Applicators in High-Dose Rate (HDR) Brachytherapy (BT) for the Treatment of Locally-Advanced Cervical-Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, L; Viswanathan, A; Damato, A [Brigham and Women’s Hospital, Boston, MA (United States)

    2015-06-15

    Purpose: To investigate the dosimetric differences associated with the use of TO or TR applicators for cervical-cancer HDR BT. Methods: The records of all cervical-cancer patients treated with image-guided HDR BT in 2013 were reviewed. Image-based planning based on isodose line and DVH metrics inspections was performed following the GEC-ESTRO recommendations. CTV volume, CTV D90, and rectum, bladder and sigmoid D2cc were collected as % of the prescription dose (80Gy EQD2). Patients receiving both TO and TR were identified and plans were compared (paired analysis). A Student T-test was used to evaluate statistical significance (p ≤ 0.05). Results: Twenty-eight patients were identified (20 TR only, 4 TO only, 4 TO and TR), associated with 116 plans (109 TR, 7 TO). Overall metrics: CTV volume, 26.5±10.4 cm3 (TR) and 39.1±14.0 cm3 (TO, p < 0.01); CTV D90, 126±28% (TR) and 110±15% (TO, p = 0.15); rectum D2cc, 56±11% (TR) and 58±19% (TO, p = 0.91); bladder D2cc, 74±20% (TR) and 88±19% (TO, p = 0.09); sigmoid D2cc, 52±17% (TR) and 49±20% (TO, p = 0.63). The paired analysis results were: CTV volume, 37.3±11.9 cm3 (TR) and 51.0±23.1 cm3 (TO, p = 0.23); CTV D90, 111±12% (TR) and 101±17% (TO, p = 0.50); rectum D2cc, 56±12% (TR) and 53±16% (TO, p = 0.71); bladder D2cc, 73±14% (TR) and 90±20% (TO, p = 0.22); sigmoid D2cc, 59±10% (TR) and 59±22% (TO, p = 0.98). Conclusion: TR and TO were both used with good dosimetric results. TO were used for patients with larger CTV volumes than TR, although paired analysis suggest that tissue distortion and contouring bias may partially explain this Result. CTV D90 on average > 80 Gy EQD2 were achieved in both groups despite the different CTV volume. Higher bladder D2cc for TO than TR was observed.

  11. Dosimetric study on the volumetric modulated arc therapy in the radiotherapy of esophageal cancer%容积调强技术在食管癌放疗中的剂量学研究

    Institute of Scientific and Technical Information of China (English)

    余建荣; 古定标; 李珍; 郭纪慈

    2016-01-01

    目的:研究旋转容积调强VMAT与固定野调强IMRT在食管癌放疗中的剂量学差异。方法2014年6月~2015年8月入组食管癌患者30例。用瓦利安Eclipse10.0计划系统分别设计单弧VMAT(Arc1)、双弧VMAT(Arc2)、和9野IMRT计划。比较三组计划在平均剂量体积直方图、靶区剂量覆盖率、危及器官和正常组织保护等方面的剂量学差异,并比较三组计划的总机器跳数(MU)和治疗时间。结果 VMAT(Arc2)靶区剂量分布均匀性(HI)和矩形度(CI)较其他两种要好(P<0.05)。危及器官方面:VMAT(Arc1)与VMAT(Arc2)比较,VMAT(Arc2)对双肺、脊髓Dmax保护优于VMAT(Arc1);VMAT(Arc2)、与IMRT 9野比较,VMAT(Arc2)对心脏Dmean、脊髓Dmax保护优于IMRT 9野;治疗时间方面:VMAT(Arc1)时间最短,需时90s,VMAT(Arc2)所需时间190~200s,IMRT 9野平均所需时间680s。结论 VMAT(Arc1)、VMAT(Arc2)、与IMRT 9野三种计划都满足临床要求。对于瓦利安Eclipse10.0计划系统VMAT(Arc2)临床使用上较普遍。%ObjectiveTo explore the dosimetric differences between volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) in the radiotherapy of esophageal cancer. Methods30 patients with esophageal cancers during June 2014 and August 2015 were recruited. The single arc VMAT (Arc 1) plan, double arc VMAT (Arc2) plan, and IMRT 9 fields plan were designed by Varian Eclipse 10.0 planning system. The dosimetric differences of average dose volume histogram, target section dose distribution, organ damage, and normal tissue protections of the three plans were compared. The total monitor unit (MU) numbers and treatment time of the three plans were compared.ResultsThe homogeneity index (HI) and conformal index (CI) of VMAT (Arc2) plan were better than the other two plans (P<0.05). In terms of organ damage, the VMAT (Arc2) plan's Dmax protections of

  12. Dosimetric study of the protection level of the bone marrow in patients with cervical or endometrial cancer for three radiotherapy techniques - 3D CRT, IMRT and VMAT. Study protocol.

    Science.gov (United States)

    Jodda, Agata; Urbański, Bartosz; Piotrowski, Tomasz; Malicki, Julian

    2016-03-01

    Background: The paper shows the methodology of an in-phantom study of the protection level of the bone marrow in patients with cervical or endometrial cancer for three radiotherapy techniques: three-dimensional conformal radiotherapy, intensity modulated radiotherapy, and volumetric modulated arc therapy, preceded by the procedures of image guidance. Methods/Design: The dosimetric evaluation of the doses will be performed in an in-house multi-element anthropomorphic phantom of the female pelvic area created by three-dimensional printing technology. The volume and position of the structures will be regulated according to the guidelines from the Bayesian network. The input data for the learning procedure of the model will be obtained from the retrospective analysis of imaging data obtained for 96 patients with endometrial cancer or cervical cancer treated with radiotherapy in our centre in 2008-2013. Three anatomical representations of the phantom simulating three independent clinical cases will be chosen. Five alternative treatment plans (1 × three-dimensional conformal radiotherapy, 2 × intensity modulated radiotherapy and 2 × volumetric modulated arc therapy) will be created for each representation. To simulate image-guided radiotherapy, ten specific recombinations will be designated, for each anatomical representation separately, reflecting possible changes in the volume and position of the phantom components. Discussion: The comparative analysis of planned measurements will identify discrepancies between calculated doses and doses that were measured in the phantom. Finally, differences between the doses cumulated in the hip plates performed by different techniques simulating the gynaecological patients' irradiation of dose delivery will be established. The results of this study will form the basis of the prospective clinical trial that will be designed for the assessment of hematologic toxicity and its correlation with the doses cumulated in the hip plates

  13. Correlation of Osteoradionecrosis and Dental Events With Dosimetric Parameters in Intensity-Modulated Radiation Therapy for Head-and-Neck Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Estilo, Cherry L. [Dental Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Wolden, Suzanne L.; Zelefsky, Michael J. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Kraus, Dennis H.; Wong, Richard J.; Shaha, Ashok R.; Shah, Jatin P. [Department of Head and Neck Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY (United States); Mechalakos, James G.; Lee, Nancy Y. [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2011-11-15

    Purpose: Osteoradionecrosis (ORN) is a known complication of radiation therapy to the head and neck. However, the incidence of this complication with intensity-modulated radiation therapy (IMRT) and dental sequelae with this technique have not been fully elucidated. Methods and Materials: From December 2000 to July 2007, 168 patients from our institution have been previously reported for IMRT of the oral cavity, nasopharynx, larynx/hypopharynx, sinus, and oropharynx. All patients underwent pretreatment dental evaluation, including panoramic radiographs, an aggressive fluoride regimen, and a mouthguard when indicated. The median maximum mandibular dose was 6,798 cGy, and the median mean mandibular dose was 3,845 cGy. Patient visits were retrospectively reviewed for the incidence of ORN, and dental records were reviewed for the development of dental events. Univariate analysis was then used to assess the effect of mandibular and parotid gland dosimetric parameters on dental endpoints. Results: With a median clinic follow-up of 37.4 months (range, 0.8-89.6 months), 2 patients, both with oral cavity primaries, experienced ORN. Neither patient had preradiation dental extractions. The maximum mandibular dose and mean mandibular dose of the 2 patients were 7,183 and 6,828 cGy and 5812 and 5335 cGy, respectively. In all, 17% of the patients (n = 29) experienced a dental event. A mean parotid dose of >26 Gy was predictive of a subsequent dental caries, whereas a maximum mandibular dose >70 Gy and a mean mandibular dose >40 Gy were correlated with dental extractions after IMRT. Conclusions: ORN is rare after head-and-neck IMRT, but is more common with oral cavity primaries. Our results suggest different mechanisms for radiation-induced caries versus extractions.

  14. A study of the anatomic changes and dosimetric consequences in adaptive CRT of non-small-cell lung cancer using deformable CT and CBCT image registration.

    Science.gov (United States)

    Ma, Changsheng; Hou, Yong; Li, Hongsheng; Li, Dengwang; Zhang, Yingjie; Chen, Siye; Yin, Yong

    2014-04-01

    The aim of this study is to evaluate anatomic lung tumor changes and dosimetric consequences utilizing the deformable daily kilovolt (KV) cone-beam computer tomography (CBCT) image registration. Five patients diagnosed with NSCLC were treated with three-dimensional conformal radiotherapy (3D CRT) and 10 daily KV CBCT image sets were acquired for each patient. Each CBCT image and plan CT were imported into the deformable image registration (DIR) system. The plan CT image was deformed by the DIR system and a new contour on CBCT was obtained by using the auto-contouring function of the DIR. These contours were individually marked as CBCT f1, CBCT f2,..., and CBCT f10, and imported into a treatment planning system (TPS). The daily CBCT plan was individually generated with the same planning criteria based on new contours. These plans were individually marked as CBCTp1, CBCTp2,..., and CBCTp10, followed by generating a dose accumulation plan (DA plan) in original pCT image contour sets by adding all CBCT plans using Varian Eclipse TPS. The maximum, minimum and mean doses to the plan target volume (PTV) in the 5 DA plans were the same with the CT plans. However, the volume of radiation 5, 10, 20, 30, and 50 Gy of the total lungs in DA plans were less than those of the CT plans. The maximum dose of the spinal cord in the DA plans were average 27.96% less than the CT plans. The mean dose for the left, right, and total lungs in the DA plans were reduced by 13.80%, 23.65%, and 12.96%, respectively. The adaptive 3D CRT based on the deformable registration can reduce the dose to the lung and the spinal cord with the same PTV dose coverage. Moreover, it provides a method for further adaptive radiotherapy exploration.

  15. 解剖结构对直肠癌IMRT计划膀胱受量影响%Relationship between anatomical factors and dosimetric sparing of the bladder in IMRT plans for rectal cancer

    Institute of Scientific and Technical Information of China (English)

    张云; 丁生苟; 蒋春灵

    2016-01-01

    目的:建立基于解剖结构定量分析直肠癌静态IMRT计划膀胱受量的统计模型。方法选择2012—2013年100例直肠癌放疗患者,制定AP布野方式的7个野逆向IMRT计划。患者解剖结构信息用膀胱与PTV和PTV外扩0.5 cm重叠区域的大小来定量分析。利用DVH对膀胱受量分析,建立膀胱受量与解剖结构信息之间数学模型,并在20例新直肠癌计划上验证所建立的模型是否准确。结果膀胱V50与膀胱和PTV重叠区域占膀胱百分体积( x%)呈线性关系( V50=0.89x-0.99);V40与膀胱和PTV外扩0.5 cm重叠区域占膀胱的百分体积( y%)也近似存在线性关系;平均剂量取决于x%和y%。模型预测20例直肠癌膀胱V50与V40偏差绝对值范围分别为(-3.13%~3.78%)和(-5.30%~5.66%),平均剂量相对偏差范围(-3.94%~3.76%)。结论这个模型提供了一种定量预估直肠癌IMRT膀胱受量方法。%Objective To establish a statistical model that can quantitatively analyze the dosimetric sparing of the bladder based on individual patient’ s anatomy in the static intensity-modulated radiotherapy (IMRT) plans for rectal cancer.Methods Static IMRT plans (7 AP fields) for 100 rectal cancer patients were used to train the model from 2012 to 2013.The anatomical features were quantitatively analyzed by the sizes of overlap regions of bladder-planning target volume (PTV) and bladder-PTV+0.5(0.5 cm margin around the PTV) .The mathematic relationship between anatomical features and dosimetric sparing of the bladder was evaluated after the bladder sparing dose was analyzed using dose-volume histogram.The established model was verified in the IMRT plans for additional 20 rectal cancer patients.Results Bladder V50 was linearly correlated with the ratio of bladder-PTV overlap size to bladder volume ( denoted as x%) , with an equation of V50=0.89x-0.99.Bladder V40 showed an

  16. SU-E-P-51: Dosimetric Comparison to Organs at Risk Sparing Using Volumetric-Modulated Arc Therapy Versus Intensity-Modulated Radiotherapy in Postoperative Radiotherapy of Left-Sided Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Qiao, L; Deng, G [Department of Oncology, Shandong University School of Medicine, Jinan, Shandong (China); Xie, J; Cheng, J; Liang, N; Zhang, J [Department of Radiation Oncology, Qianfoshan Hospital Affiliated to Shandon, Jinan, Shandong (China); Zhang, J; Luo, H [Division of Oncology, Department of Graduate, Weifang Medical College, 2610, Jinan, Shandong (China)

    2015-06-15

    Purpose: To compare the dosimetric characteristics of volumetric-modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) techniques in treatment planning for left-sided breast cancer patients with modified radical mastectomy. Methods: Twenty-four left-sided breast cancer patients treated with modified radical mastectomy were selected in this study. The planning target volume (PTV) was generated by using 7-mm uniform expansion of the clinical target volume (CTV) in all direction except the skin surface. The organs at risk (OARs) included heart, left lung, right lung, and right breast. Dose volume histograms (DVHs) were utilized to evaluate the dose distribution in PTV and OARs. Results: Both VMAT and IMRT plans met the requirement of PTV coverage. VMAT was superior to IMRT in terms of conformity, with a statistically significant difference (p=0.024). Mean doses, V5 and V10 of heart and both lungs in VMAT plans were significantly decreased compared to IMRT plans (P<0.05), but in terms of heart volume irradiated by high doses (V30 and V45), no significant differences were observed (P>0.05). For right breast, VMAT showed the reduction of V5 in comparison with IMRT (P<0.05). Additionally, the mean number of monitor units (MU) and treatment time in VMAT (357.21, 3.62 min) were significantly less than those in IMRT (1132.85, 8.74 min). Conclusion: VMAT showed similar PTV coverage and significant advantage in OARs sparing compared with IMRT, especially in terms of decreased volumes irradiated by low doses, while significantly reducing the treatment time and MU number.

  17. Dosimetric comparison of two arcs VMAT plan and IMRT plan for breast cancer post-mastectomy%乳腺癌根治术后双弧VMAT与IMRT计划的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    王佳浩; 李夏东; 邓清华; 吴稚冰; 夏冰; 赖建军; 唐荣军

    2014-01-01

    Objective To analyze the biophysical dosimetric characteristics and clinical application ability of VMAT technology for breast cancer post-mastectomy.Methods 28 patients with breast cancer (10 at left side and the other at right side) were planned in different ways respectively.One was two 90 degree arc VMAT plan and the other were 5 beam IMRT plan.The dosimetric parameters of two different plans including tumor control probability (TCP),conformity index(CI),homogeneity index (HI),V95and V110 in target,normal tissue complication probability (NTCP),V5,V20,V30 for ipsilateral lung,NCTP,D V25 for heart,D for the contralateral breast in OARs,MU and times were compared.Results The average tumor control probability (TCP) in VMAT and IMRT group was(96 ±2)% and (90 ±2)% (t =-6.28,P < 0.01),respectively.The PTV dose average homogeneity index (HI) of VMAT plans was better than that of IMRT plan (0.15 ±0.04 vs 0.22 ±0.02,t =13.29,P <0.01).For cancer position in left side,the mean dose of heart was decreased by 433.24 cGy in the VMAT plan.The NTCP of the hearts in VMAT plans had statistically significant difference compared with IMRT plans [(1.00±0.12)% vs (1.70±0.13)%,t =2.14,P <0.05].For plans of right breast cancer,the average mean dose of hearts in two control group was (3.27 ± 0.26) Gy and (6.00 ± 0.47) Gy (t =9.21,P<0.01).The total monitor unit (MU) was 530.7 in the VMAT arm and 693.9 in the IMRT arm (t =9.58,P <0.01).The treatment time was shorter in VMAT arm (t =8.40,P <0.05).Conclusions VMAT plans have better clinical value and more superior biophysical dosimetric characteristics for breast cancer post-mastectomy.%目的 比较乳腺癌根治术后双弧的容积旋转调强放射治疗(VMAT)与5野的静态调强放射治疗(IMRT)2种计划之间的剂量学差异,评估VMAT技术在乳腺癌根治术后的剂量学特点与应用能力.方法 选取28例乳腺癌根治术后患者(左侧10例,右侧18例),分别制定双90

  18. [Improved program maintenance of the CIRCIS dosimetric planning system].

    Science.gov (United States)

    Sevast'ianov, A I; Liutova, N A; Ratner, T G

    1983-03-01

    A special computer complex CIRCIS (Informatique, France) is used in the All-Union Cancer Research Center, USSR AMS, for the dosimetric planning of radiotherapy on 5 gamma-beam units and electron accelerator. Mathematical maintenance of the complex includes programs of the calculation of dose distribution for gamma-, inhibition and electron radiation but has no program of the calculation of the time of irradiation. The authors have devised and introduced into the complex such a program in the Fortran language that makes it possible to calculate within 2-3 min the time of irradiation for multifield rotation therapy using several units as a time, thus expediting the dosimetric planning for patients' irradiation.

  19. 保乳术后全乳照射 VMAT 与 IMRT 的计量学比较%Dosimetric comparison of volumetric -modulated arc therapy and intensity -modulated radiation therapy for breast cancer

    Institute of Scientific and Technical Information of China (English)

    赵金; 吴文安; 廖娟; 雎岩; 梁静; 宋丽萍

    2016-01-01

    目的:比较保乳术后全乳照射 VMAT 与静态 IMRT 的剂量学差异,探索 VMAT 的可行性。方法:2014年-2015年入组乳腺癌患者10例,左侧、右侧乳腺癌各5例。用 Varian Eclipse 计划系统分别设计双弧VMAT 和5野 IMRT 计划,PTV 处方剂量50Gy 分25次,用 Delta 4进行剂量验证。配对 t 检验比较两组计划PTV、OAR 受量、机器跳数及有效治疗时间。结果:两组计划均能满足临床剂量学要求。 VMAT 与 IMRT相比CI 值分别为(1.01±0.1)和(1.36±0.2)(P <0.05);HI 值分别为(0.124±0.01)和(0.173±0.02)(P <0.05);心脏 V20、V30、Dmean增高(P =0.041、0.012、0.002);肺 V20-V30无明显统计学差异,但是增加了患侧肺的 V5(58.2±3.5)% vs (51.4±4.2)%(P <0.05);机器跳数分别为(452±98)和(786±32)(P <0.05);有效治疗时间(2.5±0.89)min 和(15±1.78)min(P <0.05)。结论:在靶区覆盖率相似前提下,VMAT 可降低部分 OAR 受量,并能改善 CI 值、减少机器跳数、缩短有效治疗时间。Synergy 平台上的 VMAT 计划剂量稳定可靠。%Objective:To compare the dosimetric difference in VMAT and IMRT planning for breast cancer.Methods:Varian Eclipse,ten patients received radiotherapy alone after breast-conserving surgery were randomly selected.For each patient,two plans(VMAT and IMRT)were designed.In each plan,the volume of planning target volume (PTV)received prescription dose was not less than 95%.The dosimetric parameters were assessed with dosevolume histogram (DVH)and mean dose in PTV and organ at risk(OAR).Results:The irradition volume and meandose of heart and V5 of the lung can be increased by VMAT.Better conformal index(CI)and homogeneity index (HI)of PTV can be achieved.The MU and the therapy time can be reduced by the VMAT.Conclusion:The design ofVMAT plan for breast cancer should

  20. SU-E-T-338: Dosimetric Study of Volumetric Modulated Arc Therapy (VMAT) and Intensity Modulated Radiation Therapy (IMRT) for Stereotactic Body Radiation Therapy (SBRT) in Early Stage Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, I; Quinn, K; Seebach, A; Wang, H [OSF Saint Anthony Medical Center, Rockford, IL (United States); Yah, R [University of Illinois College of Medicine at Rockford, Rockford, IL (United States)

    2015-06-15

    Purpose: This study evaluates the dosimetric differences using volumetric modulated arc therapy (VMAT) in patients previously treated with intensity modulated radiation therapy IMRT for stereotactic body radiotherapy (SBRT) in early stage lung cancer. Methods: We evaluated 9 consecutive medically inoperable lung cancer patients at the start of the SBRT program who were treated with IMRT from November 2010 to October 2011. These patients were treated using 6 MV energy. The 9 cases were then re-planned with VMAT performed with arc therapy using 6 MV flattening filter free (FFF) energy with the same organs at risk (OARS) constraints. Data collected for the treatment plans included target coverage, beam on time, dose to OARS and gamma pass rate. Results: Five patients were T1N0 and four patients were T2N0 with all tumors less than 5 cm. The average GTV was 13.02 cm3 (0.83–40.87) and average PTV was 44.65 cm3 (14.06–118.08). The IMRT plans had a mean of 7.2 angles (6–9) and 5.4 minutes (3.6–11.1) per plan. The VMAT plans had a mean of 2.8 arcs (2–3) and 4.0 minutes (2.2–6.0) per plan. VMAT had slightly more target coverage than IMRT with average increase in D95 of 2.68% (1.24–5.73) and D99 of 3.65% (0.88–8.77). VMAT produced lower doses to all OARs. The largest reductions were in maximum doses to the spinal cord with an average reduction of 24.1%, esophagus with an average reduction of 22.1%, and lung with an average reduction in the V20 of 16.3% The mean gamma pass rate was 99.8% (99.2–100) at 3 mm and 3% for VMAT with comparable values for IMRT. Conclusion: These findings suggest that using VMAT for SBRT in early stage lung cancer is superior to IMRT in terms of dose coverage, OAR dose and a lower treatment delivery time with a similar gamma pass rate.

  1. SU-E-T-13: A Comparative Dosimetric Study On Radio-Dynamic Therapy for Pelvic Cancer Treatment: Strategies for Bone Marrow Dose and Volume Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Li, C [Fox Chase Cancer Center, Philadelphia, PA (United States); Renmin Hospital of Wuhan University, Wuhan, Hubei Province (China); Wang, B; Dong, Z; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States); Ge, W; Xu, L [Renmin Hospital of Wuhan University, Wuhan, Hubei Province (China)

    2015-06-15

    Purpose: Radio-dynamic therapy (RDT) is a potentially effective modality for local and systemic cancer treatment. Using RDT, the administration of a radio-sensitizer enhances the biological effect of high-energy photons. Although the sensitizer uptake ratio of tumor to normal tissue is normally high, one cannot simply neglect its effect on critical structures. In this study, we aim to explore planning strategies to improve bone marrow sparing without compromising the plan quality for RDT treatment of pelvic cancers. Methods: Ten cervical and ten prostate cancer patients who previously received radiotherapy at our institution were selected for this study. For each patient, nine plans were created using the Varian Eclipse treatmentplanning-system (TPS) with 3D-CRT, IMRT, and VMAT delivery techniques containing various gantry angle combinations and optimization parameters (dose constraints to the bone marrow). To evaluate the plans for bone marrow sparing, the dose-volume parameters V5, V10, V15, V20, V30, and V40 for bone marrow were examined. Effective doseenhancement factors for the sensitizer were used to weigh the dose-volume histograms for various tissues from individual fractions. Results: The planning strategies had different impacts on bone marrow sparing for the cervical and prostate cases. For the cervical cases, provided the bone marrow constraints were properly set during optimization, the dose to bone marrow sparing was found to be comparable between different IMRT and VMAT plans regardless of the gantry angle selection. For the prostate cases, however, careful selection of gantry angles could dramatically improve the bone marrow sparing, although the dose distribution in bone marrow was clinically acceptable for all prostate plans that we created. Conclusion: For intensity-modulated RDT planning for cervical cancer, planners should set bone marrow constraints properly to avoid any adverse damage, while for prostate cancer one can carefully select gantry

  2. The frequencies and clinical implications of mutations in 33 kinase-related genes in locally advanced rectal cancer: a pilot study.

    LENUS (Irish Health Repository)

    Abdul-Jalil, Khairun I

    2014-08-01

    Locally advanced rectal cancer (LARC: T3\\/4 and\\/or node-positive) is treated with preoperative\\/neoadjuvant chemoradiotherapy (CRT), but responses are not uniform. The phosphatidylinositol 3-kinase (PI3K), MAP kinase (MAPK), and related pathways are implicated in rectal cancer tumorigenesis. Here, we investigated the association between genetic mutations in these pathways and LARC clinical outcomes.

  3. Dosimetric study and assessment of objective functions developed in IMRT; etude dosimetrique et evaluation de fonctions objectives developpees en RCMI

    Energy Technology Data Exchange (ETDEWEB)

    Servagi-Vernat, S.; Bosset, J.F. [Service de radiotherapie, CHU IFRC, Besancon (France); Ali, D.; Giraud, P. [Hopital europeen Georges-Pompidou, Paris (France); Viard, R. [Aquilab SAS, Loos-lez-Lille (France); Fenoglietto, P. [Centre Rene-Gauducheau, Nantes (France); Lisbona, A.; Zetkin, S. [Institut Curie, Paris (France)

    2011-10-15

    The authors report a prospective and comparative analysis of the main dosimetric, physical, biological and probabilistic parameters concerning tumour target volumes and organs at risk for three new types of intensity-modulated conformational radiotherapy (IMRT): helical tomo-therapy, VMat-type dynamic arc-therapy (volumetric modulated ar therapy), and RapidArc-type dynamic arc-therapy. They also report the validation of new predictive dosimetric parameters in patients with ENT cancers. Short communication

  4. 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

  5. Development of a Standardized Method for Contouring the Lumbosacral Plexus: A Preliminary Dosimetric Analysis of this Organ at Risk Among 15 Patients Treated With Intensity-Modulated Radiotherapy for Lower Gastrointestinal Cancers and the Incidence of Radiation-Induced Lumbosacral Plexopathy

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Sun K., E-mail: sun.yi@ucdmc.ucdavis.edu [Department of Radiation Oncology, University of California, Davis Cancer Center, Sacramento, CA (United States); Mak, Walter [Department of Radiology, University of California, Davis Medical Center, Sacramento, CA (United States); Yang, Claus C.; Liu Tianxiao [Department of Radiation Oncology, University of Mississippi Medical Center, Jackson, MS (United States); Cui Jing; Chen, Allen M.; Purdy, James A.; Monjazeb, Arta M. [Department of Radiation Oncology, University of California, Davis Cancer Center, Sacramento, CA (United States); Do, Ly [Cancer Care Institute, San Jose, CA (United States)

    2012-10-01

    Purpose: To generate a reproducible step-wise guideline for the delineation of the lumbosacral plexus (LSP) on axial computed tomography (CT) planning images and to provide a preliminary dosimetric analysis on 15 representative patients with rectal or anal cancers treated with an intensity-modulated radiotherapy (IMRT) technique. Methods and Materials: A standardized method for contouring the LSP on axial CT images was devised. The LSP was referenced to identifiable anatomic structures from the L4-5 interspace to the level of the sciatic nerve. It was then contoured retrospectively on 15 patients treated with IMRT for rectal or anal cancer. No dose limitations were placed on this organ at risk during initial treatment planning. Dosimetric parameters were evaluated. The incidence of radiation-induced lumbosacral plexopathy (RILSP) was calculated. Results: Total prescribed dose to 95% of the planned target volume ranged from 50.4 to 59.4 Gy (median 54 Gy). The mean ({+-}standard deviation [SD]) LSP volume for the 15 patients was 100 {+-} 22 cm{sup 3} (range, 71-138 cm{sup 3}). The mean maximal dose to the LSP was 52.6 {+-} 3.9 Gy (range, 44.5-58.6 Gy). The mean irradiated volumes of the LSP were V40Gy = 58% {+-} 19%, V50Gy = 22% {+-} 23%, and V55Gy = 0.5% {+-} 0.9%. One patient (7%) was found to have developed RILSP at 13 months after treatment. Conclusions: The true incidence of RILSP in the literature is likely underreported and is not a toxicity commonly assessed by radiation oncologists. In our analysis the LSP commonly received doses approaching the prescribed target dose, and 1 patient developed RILSP. Identification of the LSP during IMRT planning may reduce RILSP. We have provided a reproducible method for delineation of the LSP on CT images and a preliminary dosimetric analysis for potential future dose constraints.

  6. Dosimetric comparison study between intensity modulated radiation therapy and three-dimensional conformal proton therapy for pelvic bone marrow sparing in the treatment of cervical cancer.

    Science.gov (United States)

    Song, William Y; Huh, Soon N; Liang, Yun; White, Greg; Nichols, R Charles; Watkins, W Tyler; Mundt, Arno J; Mell, Loren K

    2010-08-15

    The objective was to compare intensity-modulated radiation therapy (IMRT) with 3D conformal proton therapy (3DCPT) in the treatment of cervical cancer. In particular, each technique's ability to spare pelvic bone marrow (PBM) was of primary interest in this study. A total of six cervical cancer patients (3 postoperative and 3 intact) were planned and analyzed. All plans had uniform 1.0 cm CTV-PTV margin and satisfied the 95% PTV with 100% isodose (prescription dose = 45 Gy) coverage. Dose-volume histograms (DVH) were analyzed for comparison. The overall PTV and PBM volumes were 1035.9 ± 192.2 cc and 1151.4 ± 198.3 cc, respectively. In terms of PTV dose conformity index (DCI) and dose homogeneity index (DHI), 3DCPT was slightly superior to IMRT with 1.00 ± 0.001, 1.01 ± 0.02, and 1.10 ± 0.02, 1.13 ± 0.01, respectively. In addition, 3DCPT demonstrated superiority in reducing lower doses (i.e., V30 or less) to PBM, small bowel and bladder. Particularly in PBM, average V10 and V20 reductions of 10.8% and 7.4% (p = 0.001 and 0.04), respectively, were observed. However, in the higher dose range, IMRT provided better sparing (> V30). For example, in small bowel and PBM, average reductions in V45 of 4.9% and 10.0% (p = 0.048 and 0.008), respectively, were observed. Due to its physical characteristics such as low entrance dose, spread-out Bragg peak and finite particle range of protons, 3DCPT illustrated superior target coverage uniformity and sparing of the lower doses in PBM and other organs. Further studies are, however, needed to fully exploit the benefits of protons for general use in cervical cancer.

  7. Dosimetric effects of weight loss or gain during volumetric modulated arc therapy and intensity-modulated radiation therapy for prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pair, Matthew L. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Du, Weiliang [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Rojas, Hector D.; Kanke, James E.; McGuire, Sean E.; Lee, Andrew K.; Kuban, Deborah A. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX (United States); Kudchadker, Rajat J., E-mail: rkudchad@mdanderson.org [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, TX (United States)

    2013-10-01

    Weight loss or gain during the course of radiation therapy for prostate cancer can alter the planned dose to the target volumes and critical organs. Typically, source-to-surface distance (SSD) measurements are documented by therapists on a weekly basis to ensure that patients' exterior surface and isocenter-to-skin surface distances remain stable. The radiation oncology team then determines whether the patient has undergone a physical change sufficient to require a new treatment plan. The effect of weight change (SSD increase or decrease) on intensity-modulated radiation therapy (IMRT) or volumetric modulated arc therapy (VMAT) dosimetry is not well known, and it is unclear when rescanning or replanning is needed. The purpose of this study was to determine the effects of weight change (SSD increase or decrease) on IMRT or VMAT dose delivery in patients with prostate cancer and to determine the SSD change threshold for replanning. Whether IMRT or VMAT provides better dose stability under weight change conditions was also determined. We generated clinical IMRT and VMAT prostate and seminal vesicle treatment plans for varying SSDs for 10 randomly selected patients with prostate cancer. The differences due to SSD change were quantified by a specific dose change for a specified volume of interest. The target mean dose, decreased or increased by 2.9% per 1-cm SSD decrease or increase in IMRT and by 3.6% in VMAT. If the SSD deviation is more than 1 cm, the radiation oncology team should determine whether to continue treatment without modifications, to adjust monitor units, or to resimulate and replan.

  8. Using Generalized Equivalent Uniform Dose Atlases to Combine and Analyze Prospective Dosimetric and Radiation Pneumonitis Data From 2 Non-Small Cell Lung Cancer Dose Escalation Protocols

    Energy Technology Data Exchange (ETDEWEB)

    Liu Fan; Yorke, Ellen D. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Belderbos, Jose S.A.; Borst, Gerben R. [The Netherlands Cancer Institute, Antoni Van Leeuwenhoek Hospital, Amsterdam (Netherlands); Rosenzweig, Kenneth E. [Mount Sinai School of Medicine, New York, New York (United States); Lebesque, Joos V. [The Netherlands Cancer Institute, Antoni Van Leeuwenhoek Hospital, Amsterdam (Netherlands); Jackson, Andrew, E-mail: jacksona@mskcc.org [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2013-01-01

    Purpose: To demonstrate the use of generalized equivalent uniform dose (gEUD) atlas for data pooling in radiation pneumonitis (RP) modeling, to determine the dependence of RP on gEUD, to study the consistency between data sets, and to verify the increased statistical power of the combination. Methods and Materials: Patients enrolled in prospective phase I/II dose escalation studies of radiation therapy of non-small cell lung cancer at Memorial Sloan-Kettering Cancer Center (MSKCC) (78 pts) and the Netherlands Cancer Institute (NKI) (86 pts) were included; 10 (13%) and 14 (17%) experienced RP requiring steroids (RPS) within 6 months after treatment. gEUD was calculated from dose-volume histograms. Atlases for each data set were created using 1-Gy steps from exact gEUDs and RPS data. The Lyman-Kutcher-Burman model was fit to the atlas and exact gEUD data. Heterogeneity and inconsistency statistics for the fitted parameters were computed. gEUD maps of the probability of RPS rate {>=}20% were plotted. Results: The 2 data sets were homogeneous and consistent. The best fit values of the volume effect parameter a were small, with upper 95% confidence limit around 1.0 in the joint data. The likelihood profiles around the best fit a values were flat in all cases, making determination of the best fit a weak. All confidence intervals (CIs) were narrower in the joint than in the individual data sets. The minimum P value for correlations of gEUD with RPS in the joint data was .002, compared with P=.01 and .05 for MSKCC and NKI data sets, respectively. gEUD maps showed that at small a, RPS risk increases with gEUD. Conclusions: The atlas can be used to combine gEUD and RPS information from different institutions and model gEUD dependence of RPS. RPS has a large volume effect with the mean dose model barely included in the 95% CI. Data pooling increased statistical power.

  9. Dosimetric and radiobiological comparison of Forward Tangent Intensity Modulated Radiation Therapy (FT-IMRT) and Volumetric Modulated Arc Therapy (VMAT) for early stage whole breast cancer

    Science.gov (United States)

    Moshiri Sedeh, Nader

    Intensity Modulated Radiation Therapy (IMRT) is a well-known type of external beam radiation therapy. The advancement in technology has had an inevitable influence in radiation oncology as well that has led to a newer and faster dose delivery technique called Volumetric Modulated Arc Therapy (VMAT). Since the presence of the VMAT modality in clinics in the late 2000, there have been many studies in order to compare the results of the VMAT modality with the current popular modality IMRT for various tumor sites in the body such as brain, prostate, head and neck, cervix and anal carcinoma. This is the first study to compare VMAT with IMRT for breast cancer. The results show that the RapidArc technique in Eclipse version 11 does not improve all aspects of the treatment plans for the breast cases automatically and easily, but it needs to be manipulated by extra techniques to create acceptable plans thus further research is needed.

  10. Dosimetric analysis of tomotherapy-based intensity-modulated radiotherapy with and without bone marrow sparing for the treatment of cervical cancer

    Institute of Scientific and Technical Information of China (English)

    Fuli Zhang; Jianping Chen; Heliang He; Weidong Xu; Huayong Jiang; Yadi Wang ; Junmao Gao; Qingzhi Liu; Na Lu; Diandian Chen; Bo Yao

    2015-01-01

    Objective The aim of the study was to compare tomotherapy-based bone marrow-sparing intensity-mod-ulated radiotherapy (BMS-IMRT) with intensity-modulated radiotherapy (IMRT) without entering the pelvic bone marrow as a planning constraint in the treatment of cervical cancer after hysterectomy. Methods BMS-IMRT and IMRT plans were designed for a cohort of nine patients. The prescribed dose was 45 Gy in 1.8 Gy daily fractions, and 95% of the planned target volume received this dose. The doses were computed using a commercial y available treatment planning system with the convolution/superposi-tion algorithm. Plans were compared according to dose-volume histogram analysis in terms of planning target volume homogeneity and conformity indices (HI and CI) as wel as organ at risk dose and volume parameters. Results BMS-IMRT had advantages over IMRT in terms of CI, but was equivalent to the latter in HI. V5, V10, V20, V30, and V40 of pelvic bone marrow in BMS-IMRT decreased by 0.06%, 17.33%, 22.19%, 13.85%, and 16.46%, respectively, compared with IMRT. Except for V30 of the smal bowel and V30 and V40 of the bladder, no statistical y significant dif erences were found between BMS-IMRT and IMRT in the smal bowel, bladder, and rectum. Conclusion For cervical cancer patients receiving tomotherapy-based radiotherapy after hysterectomy, BMS-IMRT reduced pelvic bone marrow volume receiving low-dose radiation, and it may be conducive to preventing acute hematologic toxicity.

  11. Dosimetric Considerations to Determine the Optimal Technique for Localized Prostate Cancer Among External Photon, Proton, or Carbon-Ion Therapy and High-Dose-Rate or Low-Dose-Rate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Georg, Dietmar, E-mail: Dietmar.Georg@akhwien.at [Department of Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Hopfgartner, Johannes [Department of Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Gòra, Joanna [Department of Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Kuess, Peter [Department of Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Kragl, Gabriele [Department of Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Berger, Daniel [Department of Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Hegazy, Neamat [Department of Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Goldner, Gregor; Georg, Petra [Department of Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria); Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna/Allgemeines Krankenhaus der Stadt Wien, Vienna (Austria)

    2014-03-01

    Purpose: To assess the dosimetric differences among volumetric modulated arc therapy (VMAT), scanned proton therapy (intensity-modulated proton therapy, IMPT), scanned carbon-ion therapy (intensity-modulated carbon-ion therapy, IMIT), and low-dose-rate (LDR) and high-dose-rate (HDR) brachytherapy (BT) treatment of localized prostate cancer. Methods and Materials: Ten patients were considered for this planning study. For external beam radiation therapy (EBRT), planning target volume was created by adding a margin of 5 mm (lateral/anterior–posterior) and 8 mm (superior–inferior) to the clinical target volume. Bladder wall (BW), rectal wall (RW), femoral heads, urethra, and pelvic tissue were considered as organs at risk. For VMAT and IMPT, 78 Gy(relative biological effectiveness, RBE)/2 Gy were prescribed. The IMIT was based on 66 Gy(RBE)/20 fractions. The clinical target volume planning aims for HDR-BT ({sup 192}Ir) and LDR-BT ({sup 125}I) were D{sub 90%} ≥34 Gy in 8.5 Gy per fraction and D{sub 90%} ≥145 Gy. Both physical and RBE-weighted dose distributions for protons and carbon-ions were converted to dose distributions based on 2-Gy(IsoE) fractions. From these dose distributions various dose and dose–volume parameters were extracted. Results: Rectal wall exposure 30-70 Gy(IsoE) was reduced for IMIT, LDR-BT, and HDR-BT when compared with VMAT and IMPT. The high-dose region of the BW dose–volume histogram above 50 Gy(IsoE) of IMPT resembled the VMAT shape, whereas all other techniques showed a significantly lower high-dose region. For all 3 EBRT techniques similar urethra D{sub mean} around 74 Gy(IsoE) were obtained. The LDR-BT results were approximately 30 Gy(IsoE) higher, HDR-BT 10 Gy(IsoE) lower. Normal tissue and femoral head sparing was best with BT. Conclusion: Despite the different EBRT prescription and fractionation schemes, the high-dose regions of BW and RW expressed in Gy(IsoE) were on the same order of magnitude. Brachytherapy techniques

  12. Dosimetric factors predictive of late toxicity in prostate cancer radiotherapy; Radiotherapie prostatique: prediction de la toxicite tardive a partir des donnees dosimetriques

    Energy Technology Data Exchange (ETDEWEB)

    Crevoisier, R. de [Departement de radiotherapie, centre Eugene-Marquis, 35 - Rennes (France); Inserm, U 642, 35 - Rennes (France); Fiorino, C. [Medical Physics Department, San Raffaele Scientific Institute, Melghera, Milan (Italy); Dubray, B. [Departement de radiotherapie et de physique medicale, centre Henri-Becquerel, 76 - Rouen (France); EA 4108, UFR de medecine-pharmacie, QuantIF-LITIS, 76 - Rouen (France)

    2010-10-15

    Dose escalation in prostate cancer is made possible due to technological advances and to precise dose-volume constraints to limit normal tissue damage. This article is a literature review focusing on the correlations between exposure (doses and volumes) of organs at risk (OAR) and rectal, urinary, sexual and bone toxicity, as well as on mathematical models aiming at toxicity prediction. Dose-volume constraint recommendations are presented that have been shown to be associated with reduced rectal damage. Indeed, the clinical data is relatively strong for late rectal toxicity (bleeding), with constraints put on both the volume of the rectum receiving high doses ({>=}70 Gy) and the volume receiving intermediate doses (40 to 60 Gy). Predictive models of rectal toxicity (Normal Tissue Complication Probability) appear to accurately estimate toxicity risks. The correlations are much weaker for the bulb and the femoral heads, and nearly do not exist for the bladder. Further prospective studies are required, ideally taking into account patient-related risk factors (co-morbidities and their specific treatments), assays of normal tissue hypersensitivity to ionizing radiation and mathematical models applied on 3D images acquired under the treatment machine (e.g. Cone Beam CT). (authors)

  13. Preoperative treatment with capecitabine, cetuximab and radiotherapy for primary locally advanced rectal cancer : A phase II clinical trial

    NARCIS (Netherlands)

    Eisterer, Wolfgang; de Vries, Alexander; Öfner, Dietmar; Rabl, Hans; Koplmüller, Renate; Greil, Richard; Tschmelitsch, Jöerg; Schmid, Rainer; Kapp, Karin; Lukas, Peter; Sedlmayer, Felix; Höfler, Gerald; Gnant, Michael; Thaler, Josef; Widder, Joachim

    2014-01-01

    BACKGROUND/AIM: To investigate the feasibility and safety of preoperative capecitabine, cetuximab and radiation in patients with MRI-defined locally advanced rectal cancer (LARC, cT3/T4). PATIENTS AND METHODS: 31 patients with LARC were treated with cetuximab and capecitabine concomitantly with 45 G

  14. Quasi-Static Analysis of Round LaRC THUNDER Actuators

    Science.gov (United States)

    Campbell, Joel F.

    2007-01-01

    An analytic approach is developed to predict the shape and displacement with voltage in the quasi-static limit of round LaRC Thunder Actuators. The problem is treated with classical lamination theory and Von Karman non-linear analysis. In the case of classical lamination theory exact analytic solutions are found. It is shown that classical lamination theory is insufficient to describe the physical situation for large actuators but is sufficient for very small actuators. Numerical results are presented for the non-linear analysis and compared with experimental measurements. Snap-through behavior, bifurcation, and stability are presented and discussed.

  15. 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.

  16. A Multi-institutional Clinical Trial of Rectal Dose Reduction via Injected Polyethylene-Glycol Hydrogel During Intensity Modulated Radiation Therapy for Prostate Cancer: Analysis of Dosimetric Outcomes

    Energy Technology Data Exchange (ETDEWEB)

    Song, Danny Y., E-mail: dsong2@jhmi.edu [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland (United States); Herfarth, Klaus K.; Uhl, Matthias [Department of Radiation Oncology, University of Heidelberg, Heidelberg (Germany); Eble, Michael J.; Pinkawa, Michael [Department of Radiation Oncology, RWTH Aachen University, Aachen (Germany); Triest, Baukelien van; Kalisvaart, Robin [Department of Radiation Oncology, Netherlands Cancer Institute/Antoni van Leeuwenhoek Ziekenhuis, Amsterdam (Netherlands); Weber, Damien C.; Miralbell, Raymond [Department of Radiation Oncology, Geneva University, Geneva (Switzerland); DeWeese, Theodore L. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland (United States); Ford, Eric C. [Department of Radiation Oncology, University of Washington, Seattle, Washington (United States)

    2013-09-01

    Purpose: To characterize the effect of a prostate-rectum spacer on dose to rectum during external beam radiation therapy for prostate cancer and to assess for factors correlated with rectal dose reduction. Methods and Materials: Fifty-two patients at 4 institutions were enrolled into a prospective pilot clinical trial. Patients underwent baseline scans and then were injected with perirectal spacing hydrogel and rescanned. Intensity modulated radiation therapy plans were created on both scans for comparison. The objectives were to establish rates of creation of ≥7.5 mm of prostate-rectal separation, and decrease in rectal V70 of ≥25%. Multiple regression analysis was performed to evaluate the associations between preinjection and postinjection changes in rectal V70 and changes in plan conformity, rectal volume, bladder volume, bladder V70, planning target volume (PTV), and postinjection midgland separation, gel volume, gel thickness, length of PTV/gel contact, and gel left-to-right symmetry. Results: Hydrogel resulted in ≥7.5-mm prostate-rectal separation in 95.8% of patients; 95.7% had decreased rectal V70 of ≥25%, with a mean reduction of 8.0 Gy. There were no significant differences in preinjection and postinjection prostate, PTV, rectal, and bladder volumes. Plan conformities were significantly different before versus after injection (P=.02); plans with worse conformity indexes after injection compared with before injection (n=13) still had improvements in rectal V70. In multiple regression analysis, greater postinjection reduction in V70 was associated with decreased relative postinjection plan conformity (P=.01). Reductions in V70 did not significantly vary by institution, despite significant interinstitutional variations in plan conformity. There were no significant relationships between reduction in V70 and the other characteristics analyzed. Conclusions: Injection of hydrogel into the prostate-rectal interface resulted in dose reductions to rectum

  17. Dosimetric study of RapidArc plans and conventional intensity modulated radiotherapy for prostate cancer involving seminal vesicles and pelvis lymph nodes

    Directory of Open Access Journals (Sweden)

    Birendra Rout

    2016-03-01

    Full Text Available Purpose: The main purpose of this study is to (1 identify the continual diversity between conventional fixed field intensity modulation radiotherapy (IMRT and RapidArc (RA for high-risk prostate cancer; and (2 determine potential benefits and drawbacks of using for this type of treatment.Methods: A cohort of 20 prostate cases including prostate, seminal vesicles and pelvic lymph nodes was selected for this study. The primary planning target volume (PTVP and boost planning target volume (PTVB were contoured. The total prescription dose was 75.6 Gy (45 Gy to PTVP and an additional 21.6 Gy to PTVB. Two plans were generated for each PTV: multiple 7-fields for IMRT and two arcs for RA.Results: A Sigma index (IMRT: 2.75 ± 0.581; RA: 2.8 ± 0.738 for PTVP and (IMRT: 2.0 ± 0.484; RA: 2.1 ± 0.464 for PTVB indicated similar dose homogeneity inside the PTV. Conformity index (IMRT: 0.96 ± 0.047; RA: 0.95 ± 0.059 for PTVP and (IMRT: 0.97 ± 0.015; RA: 0.96 ± 0.014 for PTVB was comparable for both the techniques. IMRT offered lower mean dose to organ at risks (OARs compared to RA plans. Normal tissue integral dose in IMRT plan resulted 0.87% lower than RA plans. All the plans displayed significant increase (2.50 times for PTVP and 1.72 for PTBB in the average number of necessary monitor units (MUs with IMRT beam. Treatment delivery time of RA was 2 ‒ 6 minutes shorter than IMRT treatment.Conclusion: For PTV including pelvic lymph nodes, seminal vesicles and prostate, IMRT offered a greater degree of OARs sparing. For PTV including seminal vesicles and prostate, RA with two arcs provided comparable plan with IMRT. RA also improved the treatment efficiency due to smaller number of MUs required.

  18. Incidental dose to coronary arteries is higher in prone than in supine whole breast irradiation. A dosimetric comparison in adjuvant radiotherapy of early stage breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wuerschmidt, Florian; Stoltenberg, Solveigh; Kretschmer, Matthias; Petersen, Cordula

    2014-06-15

    Sparing of normal lung is best achieved in prone whole breast irradiation (WBI). However, exposure of the heart and coronary arteries might increase due to anterior movement of the heart in prone WBI. Treatment plans of 46 patients with large breasts irradiated for mammary cancer after breast-conserving surgery were retrospectively analyzed. The average treated breast volume of right-sided breasts (n = 33) was 1,804 ccm and 1,500 ccm for left-sided breasts (n = 13). The majority had invasive cancer (96 %) of which 61 % were pT1 and 39 % pT2 tumors. All patients received radiation therapy to the breast only. For three-dimensional (3D) treatment planning, all patients underwent a noncontrast-enhanced CT in the supine position with a wingboard and a second CT in the prone position using a prone breastboard. Nontarget volumes of the lung, heart, and coronary arteries were contoured. A total dose of 50.4 Gy was prescribed to the breast only. Differences were calculated for each patient and compared using the Wilcoxon signed-rank test. Treatment of left-sided breasts resulted in similar average mean heart doses in prone versus supine WBI (4.16 vs. 4.01 Gy; p = 0.70). The left anterior descending artery (LAD) had significantly higher dose exposure in left versus right WBI independent of position. Prone WBI always resulted in significantly higher exposures of the right circumflex artery (RCA) and LAD as compared to supine WBI. In left WBI, the mean LADprone was 33.5 Gy vs. LADsupine of 25.6 Gy (p = 0.0051). The V20prone of the LAD was 73.6 % vs. V20supine 50.4 % (p = 0.0006). The heart dose is not different between supine and prone WBI. However, in left WBI the incidental dose to the LAD with clinically relevant doses can be significantly higher in prone WBI. This is discussed controversially in the literature as it might depend on contouring and treatment techniques. We recommend contouring of LAD if patients are treated in prone WBI and evaluation of alternative

  19. Clinical and dosimetric analysis of 469 prostate cancer patients treated in France in 2005 by permanent implant brachytherapy using the Iodine 125 seeds IsoSeed Bebig: report to the French Economic committee of health products (C.E.P.S.); Analyse clinique et dosimetrique de 469 patients traites en France en 2005 par implantation prostatique de grains d'iode 125 IsoSeed Bebig: rapport pour le Comite economique des produits de sante (CEPS)

    Energy Technology Data Exchange (ETDEWEB)

    Cosset, J.M.; Gomme, S.; Henni, M.; Rosenwald, J.C.; Pontvert, B.; Asselain, D.; Chauveinca, L. [Institut Curie, 75 - Paris (France); Chauveinca, L. [Clinique Hartmann, 92 - Neuilly-sur-Seine (France); Peiffert, D. [Centre Alexis-Vautrin, 54 - Nancy (France); Guerif, S. [CHU de Poitiers, 86 - Poitiers (France); Labib, A. [Centre Rene-Huguenin, 92 - Saint-Cloud (France); Hannoun-Levi, J.M. [Centre Antoine-Lacassagne, 06 - Nice (France); Martin, P. [Polyclinique de Bourgogne, 59 - Lille (France); Quetin, G. [Centre Paul-Strauss, 67 - Strasbourg (France); Nguyen, T.D. [Centre Jean-Godinot, 51 - Reims (France); Flam, T. [Hopital Cochin, 75 - Paris (France); Thiounn, N. [Hopital Necker, 75 - Paris (France); Housset, M. [Hopital Europeen Georges-Pompidou, 75 - Paris (France)

    2007-06-15

    A French decree of February 3. 2005, allowed the Iodine 125 seeds from several companies to be reimbursed after a permanent implantation brachytherapy for a prostate cancer. Within this frame, the French 'Comite economique des produits de sante' (C.E.P.S.; Economic committee for health products) made mandatory the annual writing and publication of a follow-up study with three main aims; make sure that the seeds were used for prostate cancer patients with criteria corresponding to the national recommendations, analyze the quality of the dosimetric data, and report all side effects, complications and possible accidents. We therefore report here a clinical and dosimetric analysis of 469 patient cases treated in France in nine centers in 2005 with the Iodine 125 IsoSeed Bebig. This analysis shows that: 1) The national recommendations for selecting patients for exclusive prostate brachytherapy have been taken into account in 97% of the cases; 2) The dosimetric quality criteria totally fulfilled the recommendations in a large majority of cases; the intra-operative D90 was found to be superior to 145 Gy in 98% of the patients, and the intra-operative V100 was superior to 95% in 96% of the cases; 3) The early toxicity (mainly urinary) was found to be at the lower range of what is reported in the literature, with in particular a retention rate of 2.4%. (autho0008.

  20. Deep inspiration breath-hold (DIBH) radiotherapy in left-sided breast cancer. Dosimetrical comparison and clinical feasibility in 20 patients

    Energy Technology Data Exchange (ETDEWEB)

    Hepp, Rodrigo; Ammerpohl, Mark; Morgenstern, Christina; Erichsen, Patricia [Evangelische Kliniken Gelsenkirchen, Klinik fuer Strahlentherapie und Radioonkologie, Gelsenkirchen (Germany); Nielinger, Lisa [Evangelische Kliniken Gelsenkirchen, Klinik fuer Strahlentherapie und Radioonkologie, Gelsenkirchen (Germany); Hochschule Hamm-Lippstadt, Lippstadt (Germany); Abdallah, Abdallah [Evangelische Kliniken Gelsenkirchen, Klinik fuer Senologie, Gelsenkirchen (Germany); Galalae, Razvan [Evangelische Kliniken Gelsenkirchen, Klinik fuer Strahlentherapie und Radioonkologie, Gelsenkirchen (Germany); Christian-Albrechts-Universitaet zu Kiel, Medizinische Fakultaet, Kiel (Germany)

    2015-09-15

    Adjuvant radiotherapy after breast-conserving surgery (BCS) for breast cancer (BC) is a well-established indication. The risk of ischaemic heart disease after radiotherapy for BC increases linearly with the heart mean dose with no apparent threshold. Radiotherapy to the left breast in deep inspiration breath-hold (DIBH) reduces the dose to the heart. A new linac system with an integrated surface scanner (SS) for DIBH treatments was recently installed in our department. We tested it for potential benefits, safety, patients' acceptance/compliance and associated additional workload. Twenty consecutive patients following BCS for breast carcinoma of the left side were enrolled in our institutional DIBH protocol. We compared dose to the heart and ipsilateral lung (IL) between plans in DIBH and free breathing (FB) using standard defined parameters: mean dose, maximal dose to a volume of 2 cm{sup 3} (D{sub 2} {sub cm} {sup 3}), volume receiving ≥ 5 Gy (V{sub 5}), 10 Gy (V{sub 10}), 15 Gy (V{sub 15}) and 20 Gy (V{sub 20}). Comparison of median calculated dose values was performed using a two-tailed Wilcoxon signed rank test. DIBH was associated with a statistically significant reduction (p < 0.001) in all studied parameters for the heart and the IL. In 16 of 20 patients the heart D{sub 2} {sub cm} {sup 3} was less than 42 Gy in DIBH. In FB the heart D{sub 2} {sub cm} {sup 3} was ≥ 42 Gy in 17 of 20 patients. The median daily treatment time was 9 min. Radiotherapy of the left breast in DIBH using a SS could easily be incorporated into daily routine and is associated with significant dose reduction to the heart and IL. (orig.) [German] Die adjuvante Strahlentherapie nach brusterhaltener Operation (BCS) bei Brustkrebs (BC) ist eine seit langem anerkannte Behandlungsform. Das postradiogene Risiko einer kardialen Ischaemie steigt linear ohne erkennbaren Schwellenwert mit der mittleren Herzdosis. Die Bestrahlung der linken Brust in tiefer Inspiration unter Anhalten der

  1. Dosimetric comparing four kinds of radiation treatment planning for esophagus cancer%食管癌放射治疗计划的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    熊绮丽; 徐刚; 石勇; 倪千喜; 顾强

    2016-01-01

    比较食管癌患者应用螺旋断层(TomoHelical, TH)、径照断层(TomoDirect, TD)、容积旋转调强(Volumetric modulated arc therapy, VMAT)和固定野动态调强(Intensity modulated radiation therapy, IMRT)4种放疗计划的剂量学差异。选取18例食管癌患者,利用Pinnacle9.2计划系统设计单弧360°VMAT放疗计划和5野IMRT放疗计划。利用TomoHDTM2.0.7计划系统设计TH放疗计划和5野TD放疗计划。利用剂量体积直方图(Dose volume histogram, DVH)统计靶区剂量参数、适形性指数(Conformity index, CI)和均匀性指数(Heterogeneity index,HI),肺、心脏、脊髓剂量体积参数,出束时间和治疗跳数。TH计划靶区适形性和靶区均匀性略优于TD计划,VMAT计划靶区适形性和靶区均匀性略优于IMRT计划,且前两种计划明显优于后两种;TH计划和VMAT计划肺V20Gy、V30Gy,心脏V30Gy、V40Gy分别优于TD计划和IMRT计划;但是TD计划肺V5Gy具有其他计划都不具有的优势。TH计划优于TD计划优于VMAT计划优于IMRT计划。但如果考虑性价比,本研究认为对于食管癌 VMAT 计划是首选;如果考虑放射治疗计划的质量,TH 计划是首选;但如果靶区体积比较大,肺的低剂量无法达到临床要求时,可以考虑用TD计划解决这一难题。%Dose differences among TomoHelical (TH), TomoDirect (TD), Volumetric modulated arc therapy (VMAT) and intensity modulated radiation therapy (IMRT) for esophagus cancer were compared. Eighteen esophageal patients were chosen. The Pinnacle 9.2 treatment planning system was used to generate the VMAT plan and the five field IMRT plan. For comparison, the TH plan and five field TD plan were generated by TomoHDTM  2.0.7 treatment planning system. It was available to adopt the dose volume histograms to investigate the dose parameters of target, the statistics of conformity index (CI), the heterogeneity index (HI) of planning target volume (PTV), the dose volumetric

  2. Practical simplifications for radioimmunotherapy dosimetric models

    Energy Technology Data Exchange (ETDEWEB)

    Shen, S.; DeNardo, G.L.; O`Donnell, R.T.; Yuan, A.; DeNardo, D.A.; Macey, D.J.; DeNardo, S.J. [Univ. of California, Sacramento, CA (United States). Davis Medical Center

    1999-01-01

    Radiation dosimetry is potentially useful for assessment and prediction of efficacy and toxicity for radionuclide therapy. The usefulness of these dose estimates relies on the establishment of a dose-response model using accurate pharmacokinetic data and a radiation dosimetric model. Due to the complexity in radiation dose estimation, many practical simplifications have been introduced in the dosimetric modeling for clinical trials of radioimmunotherapy. Although research efforts are generally needed to improve the simplifications used at each stage of model development, practical simplifications are often possible for specific applications without significant consequences to the dose-response model. In the development of dosimetric methods for radioimmunotherapy, practical simplifications in the dosimetric models were introduced. This study evaluated the magnitude of uncertainty associated with practical simplifications for: (1) organ mass of the MIRD phantom; (2) radiation contribution from target alone; (3) interpolation of S value; (4) macroscopic tumor uniformity; and (5) fit of tumor pharmacokinetic data.

  3. Design, development of water tank-type lung phantom and dosimetric verification in institutions participating in a phase I study of stereotactic body radiation therapy in patients with T2N0M0 non-small cell lung cancer: Japan Clinical Oncology Group trial (JCOG0702).

    Science.gov (United States)

    Nishio, Teiji; Shirato, Hiroki; Ishikawa, Masayori; Miyabe, Yuki; Kito, Satoshi; Narita, Yuichirou; Onimaru, Rikiya; Ishikura, Satoshi; Ito, Yoshinori; Hiraoka, Masahiro

    2014-05-01

    A domestic multicenter phase I study of stereotactic body radiotherapy (SBRT) for T2N0M0 non-small cell lung cancer in inoperable patients or elderly patients who refused surgery was initiated as the Japan Clinical Oncology Group trial (JCOG0702) in Japan. Prior to the clinical study, the accuracy of dose calculation in radiation treatment-planning systems was surveyed in participating institutions, and differences in the irradiating dose between the institutions were investigated. We developed a water tank-type lung phantom appropriate for verification of the exposure dose in lung SBRT. Using this water tank-type lung phantom, the dose calculated in the radiation treatment-planning system and the measured dose using a free air ionization chamber and dosimetric film were compared in a visiting survey of the seven institutions participating in the clinical study. In all participating institutions, differences between the calculated and the measured dose in the irradiation plan were as follows: the accuracy of the absolute dose in the center of the simulated tumor measured using a free air ionization chamber was within 2%, the mean gamma value was ≤ 0.47 on gamma analysis following the local dose criteria, and the pass rate was >87% for 3%/3 mm from measurement of dose distribution with dosimetric film. These findings confirmed the accuracy of delivery doses in the institutions participating in the clinical study, so that a study with integration of the institutions could be initiated.

  4. Dosimetric results in implant and post-implant and low rate in brachytherapy prostate cancer with loose seeds and attached; Resultados dosimetricos en el implante y post-impante en braquiterapia de baja tasa en cancer de prostata con semillas sueltas y unidas

    Energy Technology Data Exchange (ETDEWEB)

    Juan-Senabre, X. J.; Albert Antequera, M.; Lopez-Tarjuelo, J.; Santos Serra, A.; Perez-Mestre, M.; Sanchez Iglesias, A. L.; Conde Moreno, A. J.; Gonzalez Vidal, V.; Beltran Persiva, J.; Muelas Soria, R.; Ferrer Albiach, C.

    2015-07-01

    The objective is determine differences dosimetry statistics on the dosimetry of the implant and post-implant in brachytherapy of low rate with implants permanent in prostate using seed of 125-I loose and attached Both in lives and in the post-prostatic plans dosimetric coverage is good and restrictions in urethra and rectum for both groups of patients are met. Not migrating with joined is evident, as well as better dosimetric homogeneity. (Author)

  5. A generalized definition of dosimetric quantities.

    Science.gov (United States)

    Kellerer, A M; Rossi, H H

    1990-04-01

    The current definitions of microdosimetric and dosimetric quantities use the notion of 'ionizing radiation'. However, this notion is not rigorously defined, and its definition would require the somewhat arbitrary choice of specified energy cut-off values for different types of particles. Instead of choosing fixed cut-off values one can extend the system of definitions by admitting the free selection of a category of types and energies of particles that are taken to be part of the field. In this way one extends the system of dosimetric quantities. Kerma and absorbed dose appear then as special cases of a more general dosimetric quantity, and an analogue to kerma can be obtained for charged particle fields; it is termed cema. A modification that is suitable for electron fields is termed reduced cema.

  6. 食管癌两种旋转调强放疗技术剂量学对比研究%Dosimetric study of two intensity-modulated arc radiotherapy in esophageal cancer

    Institute of Scientific and Technical Information of China (English)

    张若辉; 樊晓妹; 白文文; 李润霄; 曹彦坤; 韩春; 迟子锋

    2014-01-01

    Objective Comparing the dosimetric characteristics of volumetric modulated arc therapy (VMAT) and constant dose rate intensity modulated arc therapy (IMAT) in esophagus cancer to evaluate the performance of the two different arc therapy delivery techniques.Methods 22 cases of esophageal cancer patients were selected for the planning comparison study.All plans were done for IMAT and VMAT treatment plans on Oncentra 4.1 treatment planning system,prescription dose of 2 Gy in total 30 fractions.Planning objectives for PTV were at least 95% reached the prescription dose and V110 no more than 10%.The maximum dose of spinalcord below 45 Gy and double lung dose V20 ≤ 28%,V30 ≤ 18% were constrained.Plans were evaluated based on the ability to meet the dose volume histogram.The dose homogeneity index (HI),radiation conformity index (CI),radiation delivery time,monitor units and γ pass rate were also compared.SPSS 19.0 software paired ttest analysis was carried out on the two sets of data.Results The results showed that the IMAT plans in terms of the PTV's CI (t =3.35,P=0.003),D2(t =-2.27,P=0.034) lung's V30(t =-2.46,P=0.023) were better than that of VMAT group.But the VMAT plans spinal's V40 (t =2.37,P =0.027),lung's V5 (t =2.43,P =0.024) were superior to that of IMAT plans.There were no significant differences between IMAT and VMAT plans in the average dose of PTV,CTV,GTV,heart,spinal cord,double lung and the γpass rate.Conclusion IMAT presents a slight improvement in the OAR sparing in high dose with shorter treatment time when compared to VMAT.While in terms of delivered MU and tissue of low dose irradiated area is higher than that of in VMAT.These two treatment methods all can meet the clinical demand,which should be selected according to the actual situation of the patient.%目的 通过比较食管癌容积旋转调强放疗(VMAT)与固定剂量率旋转调强放疗(IMAT)计划,分析VMAT与IMAT在剂量学方面的特点.方法 对入组的22例

  7. Dosimetric implications associated to heterogeneity dose correction in stereotactic body radiation therapy (SBRT) of lung cancer; Implicaciones dosimetricas asociadas al calculo de dosis con correccion de heterogeneidad en radioterapia estereotaxica extracraneal (SBRT) de pulmon

    Energy Technology Data Exchange (ETDEWEB)

    Zucca Aparicio, D.; Perez Moreno, J. M.; Fernandez Leton, P.; Garcia Ruiz-Zorrila

    2016-10-01

    Treatment of lung lesions using stereotactic body radiation therapy (SBRT) requires algorithms with corrections that adequately model the behavior of narrow beams in the presence of tissue heterogeneities, although protocols such as RTOG 0236 excluded these kind of corrections. 100 cases were evaluated retrospectively following the RTOG 0813 and RTOG 0915 guidelines, by obtaining the deviations of the relevant dosimetric indicators from Monte Carlo (MC) and Pencil Beam (PB), maintaining the same configuration and monitor units (MU). Deviations between MC and PB have been classified according to the volume and density of the lesion. The greatest variations (up to 45% difference in D50%) are found for cases with lower volume and density, where the lesion is almost equivalent to lung tissue, given the higher proportion of air surrounding the periphery of the tumor, and the reduction of the radiation fields, resulting in a lack of electronic equilibrium that must be properly considered in the treatment planning system. These deviations involve dosimetric implications which are observable in clinical outcomes, determining how to proceed in treatment planning, to ensure that the actual dose delivered is performed accordingly to the prescription dose, while requiring the use of algorithms with a proper heterogeneity correction. (Author)

  8. Development of a dosimetric system for the quality control of breast cancer treatments; Desenvolvimento de um sistema dosimetrico para o controle de qualidade nos tratamentos de cancer de mama

    Energy Technology Data Exchange (ETDEWEB)

    Chaves, Roberio C.; Crispim, Verginia R., E-mail: rchaves@nuclear.ufrj.br, E-mail: verginia@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao de Engenharia (PEN/COPPE/lUFRJ), RJ (Brazil). Programa de Pos-Graduacao em Engenharia Nuclear; Rosa, Luiz A.R. da, E-mail: Irosa@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN), Rio de Janeiro, RJ (Brazil); Santos, Delano B.V., E-mail: delano@inca.gov.br [Instituto Nacional do Cancer (INCA/MS), Rio de Janeiro, RJ (Brazil)

    2013-11-01

    A system for evaluating the values of absorbed dose in breast teletherapy was developed, using thermoluminescent dosimeters (TLD-100), to compare them to those provided by Therapy planning system. A breast phantom was made to distribute the dosimeters TL shaped chip in breast volume and irradiate it under the same conditions of planning. Three different techniques of teletherapy were considered: one with irradiation from a therapy unit of {sup 60}Co and two with an X-ray beam coming from a 6 MV linear accelerator. Doses measures allowed checking that the performance of the quality control system used in breast cancer treatment is appropriate, since the planned doses differed about 1.5% of the responses provided by TL dosimeters.

  9. RAPIDARC (RA) in the uterine cervical cancer; dosimetric gain vs 3D-Crt; RAPIDARC (RA) en el cancer de cervix uterino; ganancia dosimetrica vs 3D-CRT

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez, J.; Garcia, B.; Quispe, K.; Gonzales, A.; Marquina, J., E-mail: jose.ramirez@aliada.com.pe [Clinica Aliada, Oncologia Integral, Av. Jose Galvez Barrenechea 1044, San Isidro, Lima (Peru)

    2014-08-15

    This work aims to quantitatively assess RAPIDARC (RA) treatments versus three dimensional-Conformal Radiation Therapy with field to field technique (3D-Crt-Fin F). 11 patients with cervical cancer treated at our institution radically or adjuvant clinical stages I-III B were evaluated. The prescribed dose was 50 Gy (2 Gy / Fr). The RA plans consisted of two isocentric complete arcs and conformational plans of 4 isocentric fields (previous, subsequent, right side and left side) with 3D-Crt-Fin F technique; both cases carried out ??in the Eclipse version 10 planner with calculation algorithm analytical anisotropic algorithm (AAA) and volumetric optimization software (for VMAT plans). Homogeneity indices (Hi), conformity indices (CI) Sigma indices (S-Index), monitor units (MU) and the time required for each treatment were compared. The mean age was 52 years (32-65) of the 11 patients 9 were clinical stages I-II B. The Hi varied from 0.052 for RA to 0.163 for 3D-Crt-Fin F (p = 0.009), and the CI between 1.005 and 1.35 (p = 0.26), the S-index from 1.2 to 3.7 (p = 0.001) and the H-index of 1.08 to 1.15 (p = 0.24). All dose limits in risk organs were met with a significant difference in the RA plans versus 3D-Crt-Fin F. In patients with cervical cancer the treatment plans quality with the indices aforementioned seems to be better with the RA technique, being observed a significant reduction of radiation to surrounding organs. (author)

  10. NASA LaRC airborne high spectral resolution lidar aerosol measurements during MILAGRO: observations and validation

    Directory of Open Access Journals (Sweden)

    L. I. Kleinman

    2009-07-01

    Full Text Available The NASA Langley Research Center (LaRC airborne High Spectral Resolution Lidar (HSRL measures vertical profiles of aerosol extinction, backscatter, and depolarization at both 532 nm and 1064 nm. In March of 2006 the HSRL participated in the Megacity Initiative: Local and Global Research Observations (MILAGRO campaign along with several other suites of instruments deployed on both aircraft and ground based platforms. This paper presents high spatial and vertical resolution HSRL measurements of aerosol extinction and optical depth from MILAGRO and comparisons of those measurements with similar measurements from other sensors and model predictions. HSRL measurements coincident with airborne in situ aerosol scattering and absorption measurements from two different instrument suites on the C-130 and G-1 aircraft, airborne aerosol optical depth (AOD and extinction measurements from an airborne tracking sunphotometer on the J-31 aircraft, and AOD from a network of ground based Aerosol Robotic Network (AERONET sun photometers are presented as a validation of the HSRL aerosol extinction and optical depth products. Regarding the extinction validation, we find bias differences between HSRL and these instruments to be less than 3% (0.01 km−1 at 532 nm, the wavelength at which the HSRL technique is employed. The rms differences at 532 nm were less than 50% (0.015 km−1. To our knowledge this is the most comprehensive validation of the HSRL measurement of aerosol extinction and optical depth to date. The observed bias differences in ambient aerosol extinction between HSRL and other measurements is within 15–20% at visible wavelengths, found by previous studies to be the differences observed with current state-of-the-art instrumentation (Schmid et al., 2006.

  11. NASA LaRC airborne high spectral resolution lidar aerosol measurements during MILAGRO: observations and validation

    Directory of Open Access Journals (Sweden)

    R. R. Rogers

    2009-04-01

    Full Text Available The NASA Langley Research Center (LaRC airborne High Spectral Resolution Lidar (HSRL measures vertical profiles of aerosol extinction, backscatter, and depolarization at both 532 nm and 1064 nm. In March of 2006 the HSRL participated in the Megacity Initiative: Local and Global Research Observations (MILAGRO campaign along with several other suites of instruments deployed on both aircraft and ground based platforms. This paper presents high spatial and vertical resolution HSRL measurements of aerosol extinction and optical depth from MILAGRO and comparisons of those measurements with similar measurements from other sensors and model predictions. HSRL measurements coincident with airborne in situ aerosol scattering and absorption measurements from two different instrument suites on the C-130 and G-1 aircraft, airborne aerosol optical depth (AOD and extinction measurements from an airborne tracking sunphotometer on the J-31 aircraft, and AOD from a network of ground based Aerosol Robotic Network (AERONET sun photometers are presented as a validation of the HSRL aerosol extinction and optical depth products. Regarding the extinction validation, we find bias differences between HSRL and these instruments to be less than 3% (0.01 km−1 at 532 nm, the wavelength at which the HSRL technique is employed. The rms differences at 532 nm were less than 50% (0.015 km−1. To our knowledge this is the most comprehensive validation of the HSRL measurement of aerosol extinction and optical depth to date. The observed bias differences in ambient aerosol extinction between HSRL and other measurements is within 15–20% at visible wavelengths, found by previous studies to be the differences observed with current state-of-the-art instrumentation (Schmid et al., 2006.

  12. Dosimetric characteristics of Novalis shaped beam surgery unit.

    Science.gov (United States)

    Yin, Fang-Fang; Zhu, Jingeng; Yan, Hui; Gaun, Haiqun; Hammoud, Rabih; Ryu, Samuel; Kim, Jae H

    2002-08-01

    The dosimetric characteristics of a new dedicated radiosurgical treatment unit are systematically measured in terms of its percent depth dose, beam profile, and relative scatter factor. High-resolution diode detector, mini-ion-chamber detector, and conventional Kodak XV films are used to measure dosimetric data for a range of field sizes from 6x6 mm to 100x100 mm. The effects of collimator size, micro-multileaf collimator shape, and detector type on the dosimetric data are investigated. Results indicate that, with careful design, accurate dosimetric data could be acquired using either a dedicated diode detector or a mini-ion-chamber detector, and film detector. Special attention is required when measuring dosimetric data for small field sizes such as 6x6 mm.

  13. Investigating the dosimetric and tumor control consequences of prostate seed loss and migration

    Energy Technology Data Exchange (ETDEWEB)

    Knaup, Courtney; Mavroidis, Panayiotis; Esquivel, Carlos; Stathakis, Sotirios; Swanson, Gregory; Baltas, Dimos; Papanikolaou, Nikos [Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States); Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States) and Department of Medical Radiation Physics, Karalinska Institutet and Stockholm University, Stockholm 17176 (Sweden); Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States); Department of Medical Physics and Engineering Offenbach Clinic, Offenbach 63069 (Germany) and Nuclear and Particle Physics Section, Physics Department, University of Athens (Greece); Department of Radiation Oncology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229 (United States)

    2012-06-15

    Purpose: Low dose-rate brachytherapy is commonly used to treat prostate cancer. However, once implanted, the seeds are vulnerable to loss and movement. The goal of this work is to investigate the dosimetric and radiobiological effects of the types of seed loss and migration commonly seen in prostate brachytherapy. Methods: Five patients were used in this study. For each patient three treatment plans were created using Iodine-125, Palladium-103, and Cesium-131 seeds. The three seeds that were closest to the urethra were identified and modeled as the seeds lost through the urethra. The three seeds closest to the exterior of prostatic capsule were identified and modeled as those lost from the prostate periphery. The seed locations and organ contours were exported from Prowess and used by in-house software to perform the dosimetric and radiobiological evaluation. Seed loss was simulated by simultaneously removing 1, 2, or 3 seeds near the urethra 0, 2, or 4 days after the implant or removing seeds near the exterior of the prostate 14, 21, or 28 days after the implant. Results: Loss of one, two or three seeds through the urethra results in a D{sub 90} reduction of 2%, 5%, and 7% loss, respectively. Due to delayed loss of peripheral seeds, the dosimetric effects are less severe than for loss through the urethra. However, while the dose reduction is modest for multiple lost seeds, the reduction in tumor control probability was minimal. Conclusions: The goal of this work was to investigate the dosimetric and radiobiological effects of the types of seed loss and migration commonly seen in prostate brachytherapy. The results presented show that loss of multiple seeds can cause a substantial reduction of D{sub 90} coverage. However, for the patients in this study the dose reduction was not seen to reduce tumor control probability.

  14. Cancer

    Science.gov (United States)

    ... cancer Non-Hodgkin lymphoma Ovarian cancer Pancreatic cancer Testicular cancer Thyroid cancer Uterine cancer Symptoms Symptoms of cancer ... tumor Obesity Pancreatic cancer Prostate cancer Stomach cancer Testicular cancer Throat or larynx cancer Thyroid cancer Patient Instructions ...

  15. Dosimetric- and Geometric Evaluation of Adaptive H&N IMRT Using Deformable Image Registration

    DEFF Research Database (Denmark)

    Eiland, R.B.; Behrens, C. F.; Sjöström, D.

    2012-01-01

    Purpose/Objective: Anatomical changes can occur during RT treatment of H&N cancer patients. This can lead to a difference between planned- and delivered dose. Adaptive RT has the potential to overcome this, utilizing deformable image registration (DIR). The purpose of this study was to evaluate...... to the ReCT in four of seven patients with regard to the target. Larger geometrical variations were observed for organs at risk (OAR). OAR contours obtained with the DIR were for nearly all patients estimated smaller than in the ReCT whereas target contours were estimated larger. The dosimetric results...

  16. 光子束和电子束在早期乳腺癌患者放疗瘤床加量计划的剂量学研究%Dosimetric study comparing photon and electron beams for boosting the tumor bed in early-stage breast cancer

    Institute of Scientific and Technical Information of China (English)

    Mohamed Mahmoud; Soha Ahmed; Ehab M. Attalla; Hassan S. Abouelenein; Shaimaa Shoier; Mohsen Barsoum

    2012-01-01

    Objective: The aim of our study was to assess and compare the potential dosimetric advantages and drawbacks of photon beams and electron beams as a boost for the tumor bed in superficial and deep seated early-stage breast cancer. Methods: We planned CTs of 10 women with early breast cancer underwent breast conservative surgery were selected. Tumor bed was defined as superficial and deep with a cut of point 4 cm, those with less than 4 cm were defined as superficial tumors representing 4 patients and those with depth of 4 cm or more were classified as deep tumors representing 6 patients. The clinical target volume (CTV) was defined as the area of architectural distortion surrounded by surgical clips. The planning target volume (PTV) was the CTV plus margin 1 cm. A dose of 10 Gy in 2 Gy fractions was given concurrently at the last week of treatment. Organs at risk (OARs) were heart, lungs, contra-lateral breast and a 5 mm thick skin segment of the breast surface. Dose volume histograms were defined to quantify the quality of concurrent treatment plans assessing target coverage and sparing OARs. The following treatment techniques were assessed: photon beam with 3D-conformal technique and a single electron beam. Results: For superficial tumors better coverage for CTV and PTV with good homogeneity with better CI was found for the 3D conformal radiotherapy (3DCRT) but with no significant planning objectives over electron beam. For deep tumors, the 3DCRT met the planning objectives for CTV, PTV with better coverage and fewer hot spots with better homogeneity and CI. For superficial tumors, OARs were spared by both techniques with better sparing for the electron beam where as for deep tumors also OARs were well spared by both techniques. Conclusion: Boosting the tumor bed in earlystage breast cancer with optimized photon may be preferred to electron beam for both superficial and deep tumors. The OARs dose sparing effect may allow for a potential long-term toxicity risk

  17. Local advanced rectal cancer perforation in the midst of preoperative chemoradiotherapy: A case report and literature review

    Science.gov (United States)

    Takase, Nobuhisa; Yamashita, Kimihiro; Sumi, Yasuo; Hasegawa, Hiroshi; Yamamoto, Masashi; Kanaji, Shingo; Matsuda, Yoshiko; Matsuda, Takeru; Oshikiri, Taro; Nakamura, Tetsu; Suzuki, Satoshi; Koma, Yu-Ichiro; Komatsu, Masato; Sasaki, Ryohei; Kakeji, Yoshihiro

    2017-01-01

    Standard chemoradiotherapy (CRT) for local advanced rectal cancer (LARC) rarely induce rectal perforation. Here we report a rare case of rectal perforation in a patient with LARC in the midst of preoperative CRT. A 56-year-old male was conveyed to our hospital exhibiting general malaise. Colonoscopy and imaging tests resulted in a clinical diagnosis of LARC with direct invasion to adjacent organs and regional lymphadenopathy. Preoperative 5-fluorouracil-based CRT was started. At 25 d after the start of CRT, the patient developed a typical fever. Computed tomography revealed rectal perforation, and he underwent emergency sigmoid colostomy. At 12 d after the surgery, the remaining CRT was completed according to the original plan. The histopathological findings after radical operation revealed a wide field of tumor necrosis and fibrosis without lymph node metastasis. We share this case as important evidence for the treatment of LARC perforation in the midst of preoperative CRT. PMID:28138443

  18. A comparative dosimetric study of 3-dimensional conformal radical radiotherapy for bladder cancer patients versus conventional 2-dimensional radical radiotherapy in NCI-Cairo, Egypt%埃及开罗国家癌症研究所膀胱癌患者的三维适形根治性放疗与传统的二维根治性放疗的比较剂量学研究

    Institute of Scientific and Technical Information of China (English)

    Mohamed Mahmoud; Hesham A. El-Hossiny; Nashaat A. Diab; Marwa A. El Razek

    2012-01-01

    Objective: This study was to compare this multiple-field conformal technique to the 2-dimensional (2D) conventional technique with respect to target volume coverage and dose to normal tissues. Methods: We conducted a single institutional prospective comparative dosimetric analysis of 15 patients who received radical radiation therapy for bladder cancer presented to Radiotherapy Department in National Cancer Institute, Cairo (Egypt), in period between November 2011 to July 2012 using 3-dimensional (3D) conformal radiotherapy technique for each patient, a second 2D conventional radiotherapy treatment plan was done, the two techniques were then compared using dose volume histogram (DVH) analysis. Results: Comparing different DVHs, it was found that the planning target volume (PTV) was adequately covered in both (3D & 2D) plans while it was demonstrated that this multiple field conformal technique produced superior distribution compared to 2D technique, with considerable sparing of rectum and to lesser extent for the head of both femora. Conclusion: From the present study, it is recommended to use 3D planning for cases of bladder cancer especially in elderly patients as it produces good coverage of the target volume as well as good sparing of the surrounding critical organs.

  19. Thermoluminescent dosimetric properties of Descalvado sand

    Energy Technology Data Exchange (ETDEWEB)

    Teixeira, M.I.; Caldas, L.V.E

    2006-07-01

    Sand samples proceeding from Descalvado, Sao Paulo, were studied with regard to their dosimetric properties using the thermoluminescence technique (TL) for high doses. These sand samples present steady physical and chemical characteristics to the end items, and they are used in the glass industry and for casting. The TL curves of the samples were obtained after an irradiation at the Gamma-Cell system ({sup 60} Co), of IPEN. The glow curves present two peaks at 80 C and 220 C approximately. Calibration curves were obtained for doses between 50 Gy and 5 kGy. The results indicate that the sand samples can be used for high-doses dosimetry in several areas of applications of ionizing radiation. (Author)

  20. ARDENT to develop advanced dosimetric techniques

    CERN Document Server

    Antonella Del Rosso

    2012-01-01

    Earlier this week, the EU-supported Marie Curie training network ARDENT kicked off at a meeting held at CERN. The overall aim of the project is the development of advanced instrumentation for radiation dosimetry. The applications range from radiation measurements around particle accelerators, onboard commercial flights and in space, to the characterization of radioactive waste and medicine, where accurate dosimetry is of vital importance.   The ARDENT (Advanced Radiation Dosimetry European Network Training) project is both a research and a training programme, which aims at developing new dosimetric techniques while providing 15 Early-Stage Researchers (ESR) with state-of-the-art training. The project, coordinated by CERN, is funded by the European Union with a contribution of about 3.9 million euros over four years. The ARDENT initiative will focus on three main technologies: gas detectors, in particular Gas Electron Multipliers (GEM) and Tissue Equivalent Proportional Counters (TEPC); solid stat...

  1. Dosimetric comparison of different radiation treatment modalities for acoustic neuromas

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Wook; Chung, Weon Kuu [Kyung Hee University Hospital at Gangdong, Seoul (Korea, Republic of); Shin, Dong Oh [Kyung Hee Medical Center, Seoul (Korea, Republic of); Shin, Dongho [National Cancer Center, Goyang (Korea, Republic of)

    2014-11-15

    The dosimetric differences for intensity-modulatedradiotherapy (IMRT), volumetric modulated arc therapy (VMAT), proton therapy(PROTON) and stereotactic radiosurgery (SRS) in patient with acoustic neuroma (AN) were compared by using the dose-volume histogram (DVH). In the present study, we estimated the dosimetric differences for patient with AN who received different treatment modalities. In this study, we found proton therapy is relatively effective treatment techniques than the other.

  2. PET/CT对非小细胞肺癌三维适形放疗中治疗计划参数的影响%Impact of PET/CT on dosimetric parameters of three-dimensional conformal radiotherapy planning in patients with non-small cell lung cancer

    Institute of Scientific and Technical Information of China (English)

    王天禄; 李光; 宋颖秋; 党军; 陈延治; 白露

    2012-01-01

    目的:观察PET/CT对非小细胞肺癌(NSCLC)三维适形放疗(3D-CRT)中治疗计划参数的影响.方法:对83例在PET/CT定位下拟行根治性3D-CRT的NSCLC患者,分别以CT图像和PET/CT融合图像勾画大体肿瘤靶区(GTVCT和GTVPET/CT),分别制定放疗计划,并对两者进行比较.结果:PET/CT明显改变44例(53.01%)患者GTV或PTV,31例PTV和(或)GTV减小,13例PTV和(或)GTV增加.根据PET/CT和CT分别制定的放疗计划在VGTV、VE50、SCM和ESM的差异有统计学意义,P值分别为0.001、0.001、0.000和0.002.结论:应用PET/CT制定NSCLC3D-CRT治疗计划可降低食管和脊髓的受照射剂量,从而有利于放疗剂量的提升.%OBJECTIVE: To investigate the impact of PET/CT on three-dimensional conformal radiotherapy (3D-CRT) planning of non-small cell lung cancer(NSCLC). METHODS: PET/CT scanning was performed in 83 pathologically proven NSCLC patients for radical radiotherapy. The gross tumor volume(GTV) was delineated on the CT images (GTVct) alone and then coregestered CT and 18F-FDG-PET data(GTVpET/cT). For each patient, two three-dimensional conformal radiotherapy plans were made: one with a CT-based target volume and one with a PET/CT-based target volume. From the dose-volume histograms and dose distributions on each plan, the dosimetric factors were analyzed and compared. RESULTS: PET/CT clearly altered the radiation therapy volume in 44 (53. 01% ,44/83) cases, while 31 with the reduction of planning target volume (PTV) and/or GTV, and 13 with the enlargement. Between the PET/CT and CT radiotherapy planning, the difference of volume of GTV (VCTv) and dosimetric parameters including esophageal volume receiving at least 50 Gy (Ve50), the maximum dose of spinal cord receiving(SCM) and the maximum dose of esophagus re-ceiving(ESM) were statistically significant (P were 0. 001, 0. 001, 0. 000 and 0. 002). CONCLUSION: The incorporation of 18 F-FDG-PET information in CT-based radiotherapy planning reduced the radiation

  3. Design and development of spine phantom to verify dosimetric accuracy of stereotactic body radiation therapy using 3D prnter

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seu Ran; Lee, Min Young; Kim, Min Joo; Park, So Hyun; Song Ji Hye; Suh, Tae Suk [Dept. of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Sohn, Jason W. [Dept. of Radiation Oncology, College of Medicine, Case Western Reserve University, Cleveland (United States)

    2015-10-15

    The purpose of this study is to verify dosimetric accuracy of delivered dose in spine SBRT as highly precise radiotherapy depending on cancer position using dedicated spine phantom based on 3D printer. Radiation therapy oncology group (RTOG) 0631 suggest different planning method in spine stereotactic body radiation therapy (SBRT) according to location of cancer owing to its distinct shape. The developed phantom especially using DLP method can be utilized as spine SBRT dosimetry research. Our study was able to confirm that the phantom was indeed similar with HU value of human spine as well as its shape.

  4. Dosimetric evaluation of a combination of brachytherapy applicators for uterine cervix cancer with involvement of the distal vagina; Avaliacao dosimetrica de uma combinacao de aplicadores para braquiterapia de tumores do colo uterino com acometimento da porcao distal da vagina

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Roger Guilherme Rodrigues [Real e Benemerita Sociedade Portuguesa de Beneficencia, Sao Paulo, SP (Brazil). Servico de Radioterapia Estereotactica; Carvalho, Heloisa de Andrade; Stuart, Silvia Radwanski; Rubo, Rodrigo Augusto [Universidade de Sao Paulo (USP), SP (Brazil). Hospital das Clinicas. Servico de Radioterapia], e-mail: handrade@hcnet.usp.br; Seraide, Rodrigo Migotto [Centro de Oncologia Campinas, SP (Brazil)

    2009-07-15

    Objective: To evaluate an alternative brachytherapy technique for uterine cervix cancer involving the distal vagina, without increasing the risk of toxicity. Materials And Methods: Theoretical study comparing three different high-dose rate intracavitary brachytherapy applicators: intrauterine tandem and vaginal cylinder (TC); tandem/ring applicator combined with vaginal cylinder (TR+C); and a virtual applicator combining both the tandem/ring and vaginal cylinder in a single device (TRC). Prescribed doses were 7 Gy at point A, and 5 Gy on the surface or at a 5 mm depth of the vaginal mucosa. Doses delivered to the rectum, bladder and sigmoid colon were kept below the tolerance limits. Volumes covered by the isodoses, respectively, 50% (V50), 100% (V100), 150% (V150) and 200% (V200) were compared. Results: Both the combined TR+C and TRC presented a better dose distribution as compared with the TC applicator. The TR+C dose distribution was similar to the TRC dose, with V150 and V200 being about 50% higher for TR+C (within the cylinder). Conclusion: Combined TR+C in a two-time single application may represent an alternative therapy technique for patients affected by uterine cervix cancer involving the distal vagina. (author)

  5. Planning analysis for locally advanced lung cancer: dosimetric and efficiency comparisons between intensity-modulated radiotherapy (IMRT, single-arc/partial-arc volumetric modulated arc therapy (SA/PA-VMAT

    Directory of Open Access Journals (Sweden)

    Zhou Xiaojuan

    2011-10-01

    Full Text Available Abstract Purpose To analyze the differences between the intensity-modulated radiotherapy (IMRT, single/partial-arc volumetric modulated arc therapy (SA/PA-VMAT techniques in treatment planning for locally advanced lung cancer. Materials and methods 12 patients were retrospectively studied. In each patient's case, several parameters were analyzed based on the dose-volume histograms (DVH of the IMRT, SA/PA-VMAT plans respectively. Also, each plan was delivered to a phantom for time comparison. Results The SA-VMAT plans showed the superior target dose coverage, although the minimum/mean/maximum doses to the target were similar. For the total and contralateral lungs, the higher V5/10, lower V20/30 and mean lung dose (MLD were observed in the SA/PA-VMAT plans (p 20, V30 and MLD of the controlateral lung more notably, comparing to those parameters of the IMRT and SA-VMAT plans respectively. The delivered monitor units (MUs and treatment times were reduced significantly with VMAT plans, especially PA-VMAT plans (for MUs: mean 458.3 vs. 439.2 vs. 435.7 MUs, p vs. 10.6 vs. 6.4 minutes, p Conclusions The SA-VMAT technique achieves highly conformal dose distribution to the target. Comparing to the IMRT plans, the higher V5/10, lower V20/30 and MLD were observed in the total and contralateral lungs in the VMAT plans, especially in the PA-VMAT plans. The SA/PA-VMAT plans also reduced treatment time with more efficient dose delivering. But the clinical benefit of the VMAT technique for locally advanced lung cancer needs further investigations.

  6. SU-E-T-632: A Dosimetric Comparison of the 3D-CRT Planning of Chest Wall in Post-Mastectomy Breast Cancer Patients, with and Without Breast Board Setup

    Energy Technology Data Exchange (ETDEWEB)

    Muzaffar, Ambreen; Masood, Asif; Ullah, Haseeb; Mehmood, Kashif; Qasim, Uzma; Afridi, M. Ali; Khan, Salim; Hameed, Abdul [Radiation Oncology Department, Shifa International Hospitals Ltd. Sector H-8/4 Islamabad (Pakistan)

    2014-06-15

    Purpose: Breast boards are used in breast radiation which increases normal lung and heart doses, when supraclavicular field is included. Therefore, in this study through dose volume histogram (DVHs), lung and heart doses comparison was done between two different setups i.e. with and without breast board, for the treatment of left chest wall and supraclavicular fossa in postmastectomy left breast cancer. Methods: In this study, CT-Simulation scans of ten breast cancer patients were done with and without breast board, at Shifa International Hospitals Islamabad, to investigate the differences between the two different setups of the irradiation of left chest wall in terms of lung and heart doses. For immobilization, support under the neck, shoulders and arms was used. Precise PLAN 2.15 treatment planning system (TPS) was used for 3D-CRT planning. The total prescribed dose for both the plans was 5000 cGy/25 fractions. The chest wall was treated with a pair of tangential photon fields and the upper supraclavicular nodal regions were treated with an anterior photon field. A mono-isocentric technique was used to match the tangential fields with the anterior field at the isocentre. The dose volume histogram was used to compare the doses of heart and ipsilateral lung. Results: Both the plans of each patient were generated and compared. DVH results showed that for the same PTV dose coverage, plans without breast board resulted in a reduction of lung and heart doses compared with the plans with breast board. There was significant reductions in V20, V<25 and mean doses for lung and V<9 and mean doses for heart. Conclusion: In comparison of both the plans, setup without breast board significantly reduced the dose-volume of the ipsilateral lung and heart in left chest wall patients. Waived registration request has been submitted.

  7. Statistical process control for IMRT dosimetric verification.

    Science.gov (United States)

    Breen, Stephen L; Moseley, Douglas J; Zhang, Beibei; Sharpe, Michael B

    2008-10-01

    Patient-specific measurements are typically used to validate the dosimetry of intensity-modulated radiotherapy (IMRT). To evaluate the dosimetric performance over time of our IMRT process, we have used statistical process control (SPC) concepts to analyze the measurements from 330 head and neck (H&N) treatment plans. The objectives of the present work are to: (i) Review the dosimetric measurements of a large series of consecutive head and neck treatment plans to better understand appropriate dosimetric tolerances; (ii) analyze the results with SPC to develop action levels for measured discrepancies; (iii) develop estimates for the number of measurements that are required to describe IMRT dosimetry in the clinical setting; and (iv) evaluate with SPC a new beam model in our planning system. H&N IMRT cases were planned with the PINNACLE treatment planning system versions 6.2b or 7.6c (Philips Medical Systems, Madison, WI) and treated on Varian (Palo Alto, CA) or Elekta (Crawley, UK) linacs. As part of regular quality assurance, plans were recalculated on a 20-cm-diam cylindrical phantom, and ion chamber measurements were made in high-dose volumes (the PTV with highest dose) and in low-dose volumes (spinal cord organ-at-risk, OR). Differences between the planned and measured doses were recorded as a percentage of the planned dose. Differences were stable over time. Measurements with PINNACLE3 6.2b and Varian linacs showed a mean difference of 0.6% for PTVs (n=149, range, -4.3% to 6.6%), while OR measurements showed a larger systematic discrepancy (mean 4.5%, range -4.5% to 16.3%) that was due to well-known limitations of the MLC model in the earlier version of the planning system. Measurements with PINNACLE3 7.6c and Varian linacs demonstrated a mean difference of 0.2% for PTVs (n=160, range, -3.0%, to 5.0%) and -1.0% for ORs (range -5.8% to 4.4%). The capability index (ratio of specification range to range of the data) was 1.3 for the PTV data, indicating that almost

  8. Dosimetric differences in flattened and flattening filter-free beam treatment plans

    Directory of Open Access Journals (Sweden)

    Yue Yan

    2016-01-01

    Full Text Available This study investigated the dosimetric differences in treatment plans from flattened and flattening filter-free (FFF beams from the TrueBeam System. A total of 104 treatment plans with static (sliding window intensity-modulated radiotherapy beams and volumetric-modulated arc therapy (VMAT beams were generated for 15 patients involving three cancer sites. In general, the FFF beam provides similar target coverage as the flattened beam with improved dose sparing to organ-at-risk (OAR. Among all three cancer sites, the head and neck showed more important differences between the flattened beam and FFF beam. The maximum reduction of the FFF beam in the mean dose reached up to 2.82 Gy for larynx in head and neck case. Compared to the 6 MV flattened beam, the 10 MV FFF beam provided improved dose sparing to certain OARs, especially for VMAT cases. Thus, 10 MV FFF beam could be used to improve the treatment plan.

  9. Dosimetric optimization of a conical breast brachytherapy applicator for improved skin dose sparing

    Energy Technology Data Exchange (ETDEWEB)

    Yang Yun; Rivard, Mark J. [Biomedical Engineering and Biotechnology, University of Massachusetts Lowell, Lowell, Massachusetts 01854 (United States); Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

    2010-11-15

    Purpose: Both the AccuBoost D-shaped and round applicators have been dosimetrically characterized and clinically used to treat patients with breast cancer. While the round applicators provide conformal dose coverage, under certain clinical circumstances the breast skin dose may be higher than preferred. The purpose of this study was to modify the round applicators to minimize skin dose while not substantially affecting dose uniformity within the target volume and reducing the treatment time. Methods: In order to irradiate the intended volume while sparing critical structures such as the skin, the current round applicator design has been augmented through the addition of an internal truncated cone (i.e., frustum) shield. Monte Carlo methods and clinical constraints were used to design the optimal cone applicator. With the cone applicator now defined as the entire assembly including the surrounding tungsten-alloy shell holding the HDR {sup 192}Ir source catheter, the applicator height was reduced to diminish the treatment time while minimizing skin dose. Monte Carlo simulation results were validated using both radiochromic film and ionization chamber measurements based on established techniques. Results: The optimal cone applicators diminished the maximum skin dose by 15%-32% (based on the applicator diameter and breast separation) with the tumor dose reduced by less than 3% for a constant exposure time. Furthermore, reduction in applicator height diminished the treatment time by up to 30%. Radiochromic film and ionization chamber dosimetric results in phantom agreed with Monte Carlo simulation results typically within 3%. Larger differences were outside the treatment volume in low dose regions or associated with differences between the measurement and Monte Carlo simulation environments. Conclusions: A new radiotherapy treatment device was developed and dosimetrically characterized. This set of applicators significantly reduces the skin dose and treatment time while

  10. Gamma Putty dosimetric studies in electron beam

    Directory of Open Access Journals (Sweden)

    Aime M Gloi

    2016-01-01

    Full Text Available Traditionally, lead has been used for field shaping in megavoltage electron beams in radiation therapy. In this study, we analyze the dosimetric parameters of a nontoxic, high atomic number (Z = 83, bismuth-loaded material called Gamma Putty that is malleable and can be easily molded to any desired shape. First, we placed an ionization chamber at different depths in a solid water phantom under a Gamma Putty shield of thickness (t = 0, 3, 5, 10, 15, 20, and 25 mm, respectively and measured the ionizing radiation on the central axis (CAX for electron beam ranging in energies from 6 to 20 MeV. Next, we investigated the relationship between the relative ionization (RI measured at a fixed depth for several Gamma Putty shield at different cutout diameters ranging from 2 to 5 cm for various beam energies and derived an exponential fitting equation for clinical purposes. The dose profiles along the CAX show that bremsstrahlung dominates for Gamma Putty thickness >15 mm. For high-energy beams (12-20 MeV and all Gamma Putty thicknesses up to 25 mm, RI below 5% could not be achieved due to the strong bremsstrahlung component. However, Gamma Putty is a very suitable material for reducing the transmission factor below 5% and protecting underlying normal tissues for low-energy electron beams (6-9 MeV.

  11. Gamma Putty dosimetric studies in electron beam

    Science.gov (United States)

    Gloi, Aime M.

    2016-01-01

    Traditionally, lead has been used for field shaping in megavoltage electron beams in radiation therapy. In this study, we analyze the dosimetric parameters of a nontoxic, high atomic number (Z = 83), bismuth-loaded material called Gamma Putty that is malleable and can be easily molded to any desired shape. First, we placed an ionization chamber at different depths in a solid water phantom under a Gamma Putty shield of thickness (t = 0, 3, 5, 10, 15, 20, and 25 mm, respectively) and measured the ionizing radiation on the central axis (CAX) for electron beam ranging in energies from 6 to 20 MeV. Next, we investigated the relationship between the relative ionization (RI) measured at a fixed depth for several Gamma Putty shield at different cutout diameters ranging from 2 to 5 cm for various beam energies and derived an exponential fitting equation for clinical purposes. The dose profiles along the CAX show that bremsstrahlung dominates for Gamma Putty thickness >15 mm. For high-energy beams (12–20 MeV) and all Gamma Putty thicknesses up to 25 mm, RI below 5% could not be achieved due to the strong bremsstrahlung component. However, Gamma Putty is a very suitable material for reducing the transmission factor below 5% and protecting underlying normal tissues for low-energy electron beams (6–9 MeV). PMID:27651563

  12. Single-fraction high-dose-rate brachytherapy using real-time transrectal ultrasound based planning in combination with external beam radiotherapy for prostate cancer: dosimetrics and early clinical results

    Science.gov (United States)

    Lauche, Olivier; Delouya, Guila; Taussky, Daniel; Menard, Cynthia; Béliveau-Nadeau, Dominic; Hervieux, Yannick; Larouche, Renée

    2016-01-01

    Purpose To validate the feasibility of a single-fraction high-dose-rate brachytherapy (HDRBT) boost for prostate cancer using real-time transrectal ultrasound (TRUS) based planning. Material and methods From August 2012 to September 2015, 126 patients underwent a single-fraction HDRBT boost of 15 Gy using real-time TRUS based planning. External beam radiation therapy (EBRT) (37.5 Gy/15 fractions, 44 Gy/22 fractions, or 45 Gy/25 fractions) was performed before (31%) or after (69%) HDRBT boost. Genito-urinary (GU) and gastro-intestinal (GI) toxicity were assessed 4 and 12 months after the end of combined treatment using the international prostate symptom score scale (IPSS) and the common terminology criteria for adverse events (CTCAE) v3.0. Results All dose-planning objectives were achieved in 90% of patients. Prostate D90 ≥ 105% and ≤ 115% was achieved in 99% of patients, prostate V150 ≤ 40% in 99%, prostate V200 < 11% in 96%, urethra D10 < 120% for 99%, urethra V125 = 0% in 100%, and rectal V75 < 1 cc in 93% of patients. Median IPSS score was 4 at baseline and did not change at 4 and 12 months after combined treatment. No patients developed ≥ grade 2 GI toxicity. With a median follow-up of 10 months, only two patients experienced biochemical failure. Among patients who didn't receive ADT, cumulative percentage of patients with PSA ≤ 1 ng/ml at 4 and 18 months was respectively 23% and 66%. Conclusions Single-fraction HDRBT boost of 15 Gy using real-time TRUS based planning achieves consistently high dosimetry quality. In combination with EBRT, toxicity outcomes appear promising. A longer follow-up is needed to assess long-term outcome and toxicities. PMID:27257413

  13. A dosimetric analysis of the aeroformTM tissue expander in radiation therapy

    Directory of Open Access Journals (Sweden)

    Tai Tran

    2014-08-01

    that dose homogeneity was difficult due to the metallic reservoir and we recommend stringent patient dose monitoring when using this expander during radiotherapy.-----------------------------Cite this article as: Tran T, Ding W, Subramanian B, Melven L, Chao M, Farrow H, Baker C. A dosimetric analysis of the aeroformTM tissue expander in radiation therapy. Int J Cancer Ther Oncol 2014; 2(3:020316. DOI: 10.14319/ijcto.0203.16

  14. Basics of particle therapy II biologic and dosimetric aspects of clinical hadron therapy.

    Science.gov (United States)

    Rong, Yi; Welsh, James

    2010-12-01

    Besides photons and electrons, high-energy particles like protons, neutrons, ⁴He ions or heavier ions (C, Ne, etc) have been finding increasing applications in the treatment of radioresistant tumors and tumors located near critical structures. The main difference between photons and hadrons is their different biologic effect and depth-dose distribution. Generally speaking, protons are superior in dosimetric aspects whereas neutrons have advantages in biologic effectiveness because of the high linear energy transfer. In 1946 Robert Wilson first published the physical advantages in dose distribution of ion particles for cancer therapy. Since that time hadronic radiotherapy has been intensively studied in physics laboratories worldwide and clinical application have gradually come to fruition. Hadron therapy was made possible by the advances in accelerator technology, which increases the particles' energy high enough to place them at any depth within the patient's body. As a follow-up to the previous article Introduction to Hadrons, this review discusses certain biologic and dosimetric aspects of using protons, neutrons, and heavy charged particles for radiation therapy.

  15. Benchmarking Dosimetric Quality Assessment of Prostate Intensity-Modulated Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Senthi, Sashendra, E-mail: sasha.senthi@petermac.org [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Gill, Suki S. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Haworth, Annette; Kron, Tomas; Cramb, Jim [Department of Physical Sciences, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Rolfo, Aldo [Radiation Therapy Services, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Thomas, Jessica [Biostatistics and Clinical Trials, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Duchesne, Gillian M. [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia); Hamilton, Christopher H.; Joon, Daryl Lim [Radiation Oncology Department, Austin Repatriation Hospital, Heidelberg, VIC (Australia); Bowden, Patrick [Radiation Oncology Department, Tattersall' s Cancer Center, East Melbourne, VIC (Australia); Foroudi, Farshad [Division of Radiation Oncology, Peter MacCallum Cancer Center, East Melbourne, VIC (Australia)

    2012-02-01

    Purpose: To benchmark the dosimetric quality assessment of prostate intensity-modulated radiotherapy and determine whether the quality is influenced by disease or treatment factors. Patients and Methods: We retrospectively analyzed the data from 155 consecutive men treated radically for prostate cancer using intensity-modulated radiotherapy to 78 Gy between January 2007 and March 2009 across six radiotherapy treatment centers. The plan quality was determined by the measures of coverage, homogeneity, and conformity. Tumor coverage was measured using the planning target volume (PTV) receiving 95% and 100% of the prescribed dose (V{sub 95%} and V{sub 100%}, respectively) and the clinical target volume (CTV) receiving 95% and 100% of the prescribed dose. Homogeneity was measured using the sigma index of the PTV and CTV. Conformity was measured using the lesion coverage factor, healthy tissue conformity index, and the conformity number. Multivariate regression models were created to determine the relationship between these and T stage, risk status, androgen deprivation therapy use, treatment center, planning system, and treatment date. Results: The largest discriminatory measurements of coverage, homogeneity, and conformity were the PTV V{sub 95%}, PTV sigma index, and conformity number. The mean PTV V{sub 95%} was 92.5% (95% confidence interval, 91.3-93.7%). The mean PTV sigma index was 2.10 Gy (95% confidence interval, 1.90-2.20). The mean conformity number was 0.78 (95% confidence interval, 0.76-0.79). The treatment center independently influenced the coverage, homogeneity, and conformity (all p < .0001). The planning system independently influenced homogeneity (p = .038) and conformity (p = .021). The treatment date independently influenced the PTV V{sub 95%} only, with it being better at the start (p = .013). Risk status, T stage, and the use of androgen deprivation therapy did not influence any aspect of plan quality. Conclusion: Our study has benchmarked measures

  16. Dosimetric accuracy of a staged radiosurgery treatment

    Science.gov (United States)

    Cernica, George; de Boer, Steven F.; Diaz, Aidnag; Fenstermaker, Robert A.; Podgorsak, Matthew B.

    2005-05-01

    For large cerebral arteriovenous malformations (AVMs), the efficacy of radiosurgery is limited since the large doses necessary to produce obliteration may increase the risk of radiation necrosis to unacceptable levels. An alternative is to stage the radiosurgery procedure over multiple stages (usually two), effectively irradiating a smaller volume of the AVM nidus with a therapeutic dose during each session. The difference between coordinate systems defined by sequential stereotactic frame placements can be represented by a translation and a rotation. A unique transformation can be determined based on the coordinates of several fiducial markers fixed to the skull and imaged in each stereotactic coordinate system. Using this transformation matrix, isocentre coordinates from the first stage can be displayed in the coordinate system of subsequent stages allowing computation of a combined dose distribution covering the entire AVM. The accuracy of this approach was tested on an anthropomorphic head phantom and was verified dosimetrically. Subtle defects in the phantom were used as control points, and 2 mm diameter steel balls attached to the surface were used as fiducial markers and reference points. CT images (2 mm thick) were acquired. Using a transformation matrix developed with two frame placements, the predicted locations of control and reference points had an average error of 0.6 mm near the fiducial markers and 1.0 mm near the control points. Dose distributions in a staged treatment approach were accurately calculated using the transformation matrix. This approach is simple, fast and accurate. Errors were small and clinically acceptable for Gamma Knife radiosurgery. Accuracy can be improved by reducing the CT slice thickness.

  17. Dosimetric accuracy of a staged radiosurgery treatment

    Energy Technology Data Exchange (ETDEWEB)

    Cernica, George [Department of Physics, State University of New York at Buffalo, Buffalo, NY 14263 (United States); Boer, Steven F de [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Diaz, Aidnag [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Fenstermaker, Robert A [Department of Neurosurgery, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States); Podgorsak, Matthew B [Department of Radiation Oncology, Roswell Park Cancer Institute and the State University of New York at Buffalo, Buffalo, NY 14263 (United States)

    2005-05-07

    For large cerebral arteriovenous malformations (AVMs), the efficacy of radiosurgery is limited since the large doses necessary to produce obliteration may increase the risk of radiation necrosis to unacceptable levels. An alternative is to stage the radiosurgery procedure over multiple stages (usually two), effectively irradiating a smaller volume of the AVM nidus with a therapeutic dose during each session. The difference between coordinate systems defined by sequential stereotactic frame placements can be represented by a translation and a rotation. A unique transformation can be determined based on the coordinates of several fiducial markers fixed to the skull and imaged in each stereotactic coordinate system. Using this transformation matrix, isocentre coordinates from the first stage can be displayed in the coordinate system of subsequent stages allowing computation of a combined dose distribution covering the entire AVM. The accuracy of this approach was tested on an anthropomorphic head phantom and was verified dosimetrically. Subtle defects in the phantom were used as control points, and 2 mm diameter steel balls attached to the surface were used as fiducial markers and reference points. CT images (2 mm thick) were acquired. Using a transformation matrix developed with two frame placements, the predicted locations of control and reference points had an average error of 0.6 mm near the fiducial markers and 1.0 mm near the control points. Dose distributions in a staged treatment approach were accurately calculated using the transformation matrix. This approach is simple, fast and accurate. Errors were small and clinically acceptable for Gamma Knife radiosurgery. Accuracy can be improved by reducing the CT slice thickness.

  18. Dosimetric advantages of IMPT over IMRT for laser-accelerated proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Luo, W; Li, J; Fourkal, E; Fan, J; Xu, X; Chen, Z; Jin, L; Price, R; Ma, C-M [Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, PA 19111 (United States)], E-mail: wei.luo@duke.edu

    2008-12-21

    As a clinical application of an exciting scientific breakthrough, a compact and cost-efficient proton therapy unit using high-power laser acceleration is being developed at Fox Chase Cancer Center. The significance of this application depends on whether or not it can yield dosimetric superiority over intensity-modulated radiation therapy (IMRT). The goal of this study is to show how laser-accelerated proton beams with broad energy spreads can be optimally used for proton therapy including intensity-modulated proton therapy (IMPT) and achieve dosimetric superiority over IMRT for prostate cancer. Desired energies and spreads with a varying {delta}E/E were selected with the particle selection device and used to generate spread-out Bragg peaks (SOBPs). Proton plans were generated on an in-house Monte Carlo-based inverse-planning system. Fifteen prostate IMRT plans previously used for patient treatment have been included for comparison. Identical dose prescriptions, beam arrangement and consistent dose constrains were used for IMRT and IMPT plans to show the dosimetric differences that were caused only by the different physical characteristics of proton and photon beams. Different optimization constrains and beam arrangements were also used to find optimal IMPT. The results show that conventional proton therapy (CPT) plans without intensity modulation were not superior to IMRT, but IMPT can generate better proton plans if appropriate beam setup and optimization are used. Compared to IMRT, IMPT can reduce the target dose heterogeneity ((D{sub 5}-D{sub 95})/D{sub 95}) by up to 56%. The volume receiving 65 Gy and higher (V{sub 65}) for the bladder and the rectum can be reduced by up to 45% and 88%, respectively, while the volume receiving 40 Gy and higher (V{sub 40}) for the bladder and the rectum can be reduced by up to 49% and 68%, respectively. IMPT can also reduce the whole body non-target tissue dose by up to 61% or a factor 2.5. This study has shown that the laser

  19. Electromagnetic and Thermal Dosimetric Techniques in Humans and its Application

    Science.gov (United States)

    Hirata, Akimasa; Fujiwara, Osamu

    There has been increasing public concern about the adverse health effects of human exposure to radio frequency fields. Radio frequency fields are also used for medical application. This paper reviews electromagnetic and thermal computational dosimetric techniques, which has been developed by the authors. The feature of the thermal dosimetric method is that body core temperature can be computed reasonably unlike conventional method. This scheme is particularly useful for intense localized or whole-body electromagnetic wave exposure. Computational examples are shown to verify the effectiveness of the proposal.

  20. FBX aqueous chemical dosimeter for measurement of dosimetric parameters

    Energy Technology Data Exchange (ETDEWEB)

    Moussous, O., E-mail: o.moussous@crna.d [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz Fanon B.P. 399, 16000 Alger (Algeria); Medjadj, T. [Centre de Recherche Nucleaire d' Alger (CRNA), 02 Boulevard Frantz Fanon B.P. 399, 16000 Alger (Algeria); Benguerba, M. [Faculte de Physique, Universite des Sciences et de la Technologie Houari-Boumediene USTHB, Alger (Algeria)

    2011-02-15

    We investigated the ferrous sulphate-benzoic acid-xylenol orange (FBX) aqueous chemical dosimeter for measurement of dosimetric parameters such as the output factor, backscatter factor and lateral beam profiles for different square fields sizes for {sup 60}Co {gamma}-rays. A water phantom was employed to measure these parameters. An ionization chamber (IC) was used for calibration and comparison. A comparison of the resulting measurements with an ionization chamber's measured parameters showed good agreement. We thus believe that the tissue equivalent FBX dosimetry system can measure the dosimetric parameters for {sup 60}Co with reasonable accuracy.

  1. Dosimetric Comparison Between VMAT and IMRT for Different Tumor Volume and Different Lesion Length of E-sophageal Cancer%VMAT与IMRT在不同瘤体体积和瘤体长度食管癌中的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    杨瑜; 刘丽虹; 韩春; 王澜; 田华

    2015-01-01

    Objective To compare the dosimetric differences between volumetric modulated arc therapy ( VMAT ) and static intensity modulated radiotherapy ( IMRT) for different tumor volume and different lesion length of esophageal cancer. Meth-ods The Elekta Oncentra4. 1 Planning System was adopted to design both VMAT and IMRT plans for fifty patients who were diag-nosed with thoracic esophageal cancer. All treatment plans of the 50 cases were evaluated using the dose-volume histogram parame-ters of PTV and the organs at risk. The monitor units (MUs) were Also examined. Results ①For GTV volume55cm 3 group. ②For lesion length9cm group,VMAT plan achieved lower D90 and V100, whereas HI and CI were not significantly different.③For GTV vol-ume9cm group, VMAT plan resulted in a slightly lower lung V10 and higher lung V30. For GTV volume>55cm 3 group,VMAT plan resulted in a lower lung V10. For 5~9cm group,sparing of lungs showed no statistically significant differences between the two techniques.④The Dmean of heart in VMAT plan was not statistically different in comparison with IMRT plan for GTV volume>55cm 3 group and lesion length>9cm group, but higher than in IMRT for GTV volume55cm 3 group, and by an average of 16. 1% and 16. 0% in the 5~9cm group and >9cm group. However, VMAT plan provided an aver-age of 10. 4% and 14. 4% more monitor units than IMRT plan in the volume55cm3组, VMAT PTVV100低于IMRT。②GTV长度9cm组,VMAT D90、V100低于IMRT,HI和CI无明显差异。③体积9cm组,VMAT肺V10降低,V30增高;体积>55cm 3组,VMAT肺V10低于IMRT;长度5~9cm组,两种计划差异无统计学意义。④GTV体积55cm 3和长度>9cm组两种计划心脏受量相似。脊髓Dmax两种计划比较差异无统计学意义。⑤在机器调数( MU)方面GTV体积15~55cm 3和>55cm 3组及GTV长度5~9cm和>9cm组,VMAT的MU较IMRT分别减少11.3%、18.1%、16.1%和16.0%。而体积<15cm3和长度<5cm组,VMAT的MU则分别增加了10.4%和14.4%。结论在

  2. SOCIAL FRANCHISING IN CONTEXT OF MARKETING LONG-TERM AND REVERSIBLE CONTRACEPTIVES (LARCS IN UGANDA: ANALYSIS OF PACE SOCIAL FRANCHISE MODEL

    Directory of Open Access Journals (Sweden)

    Simon SENSALIRE

    2015-02-01

    Full Text Available Background: Uganda is TFR is among the world’s highest at six children per woman, and contributes to the rising rate of poverty and maternal and infant mortality across the country. A social franchise model was adopted in Uganda to market and scale up contraceptive prevalence through the private sector. In 2008 PACE launched the Women’s Health Project, a core component of their reproductive health strategy to increase access to and demand for affordable, quality long‐term Family Planning (FP services, through the setup of a network of private healthcare providers, branded as “ProFam” social franchise health facilities. The program expanded and included services aimed to offer and improve reproductive health services, limiting births through increased use of IUDs and implants as well change negative perceptions to FP. Until 2014, this network consisted of 189 private facilities spread out in 56 districts, following a business model of social franchising. Methods: The multifaceted effect of the social franchise intervention under PACE was then measured through a longitudinal cross sectional survey on perceptions towards Long-Term and Reversible Contraceptives (LARCs use among the target population through a cross-sectional studies over two periods. The studies covered 53 districts hosting 194 privately owned health facilities branded Profam. Multi-stage cluster sampling approaches was used to draw a representative sample of women of reproductive age group. However, for Kampala (capital city, given its population size, the catchment area was restricted to a parish/Ward. Findings: There is an evident rise in current use of FP methods among WRA. Availability of LARCs particularly IUCDs significantly increased over the two time periods. Use of FP services among WRA is a socially sanctioned behavior/practice. There was reported increase in social support for FP services. There were high levels of correct knowledge about FP services and

  3. Dose reader of dosimetric foil; Czytnik dawki folii dozymetrycznej

    Energy Technology Data Exchange (ETDEWEB)

    Machaj, B.; Strzalkowski, J.; Smolko, K.

    1997-12-31

    Read out the absorbance of a dosimetric foil is accomplished by two beam spectrophotometer. Such a solution makes possible the compensation of light source instabilities and ensures higher stability of the dose reader. The error of absorbance measurement caused by the instabilities does not exceed 0.0004 A. (author). 3 refs, 3 figs.

  4. Dosimetric uncertainties related to the elasticity of bladder and rectal walls: Adenocarcinoma of the prostate

    CERN Document Server

    Voyant, Cyril; Delphine, Leschi; Briancon, Jerome; Marcovici, Celine Lantieri; 10.1016/j.canrad.2010.12.006

    2011-01-01

    Purpose. - Radiotherapy is an important treatment for prostate cancer.During treatment sessions, bladder and rectal repletion is difficult to quantify and cannot be measured with a single and initial CT scan acquisition. Some methods, such as image-guided radiation therapy and dose-guided radiation therapy, aimto compensate thismissing information through periodic CT acquisitions. The aimis to adapt patient's position, beam configuration or prescribed dose for a dosimetric compliance. Methods. -We evaluated organmotion (and repletion) for 54 patients after having computed the original ballistic on a new CT scan acquisition. A new delineation was done on the prostate, bladder and rectum to determine the newdisplacements and define organ dosesmistakes (equivalent uniformdose, average dose and dose-volume histograms). Results. - The new CT acquisitions confirmed that bladder and rectal volumes were not constant during sessions. Some cases showed that previously validated treatment plan became unsuitable. A propo...

  5. Dosimetric effect of rotational errors for lung stereotactic body radiation therapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong Min; Lee, Jae Gi; Kim, Hyun Suk; Kim, Jung In; Kim, Hak Jae; Ye, Sung Joon [Radiation Oncology, Seoul National University Hospital, Seoul (Korea, Republic of)

    2014-04-15

    The aim of this study is to evaluate the dosimetric effects on target volume and organs at risk (OARs) due to roll rotational errors in treatment setup of SBRT for lung cancer delivered with volumetric modulated arc therapy (VMAT) technique. Roll rotational setup errors in lung SBRT significantly influenced the coverage of target volume using VMAT technique. This could be in part compensated by the translational couch correction. However, in spite of the translational correction, the delivered doses to the spinal cord could be more than the calculated doses. Therefore if rotational setup errors exist during lung SBRT using VMAT technique, the rotational correction would rather be considered to prevent over-irradiation of normal tissues than the translational correction.

  6. Conventional Versus Automated Implantation of Loose Seeds in Prostate Brachytherapy: Analysis of Dosimetric and Clinical Results

    Energy Technology Data Exchange (ETDEWEB)

    Genebes, Caroline, E-mail: genebes.caroline@claudiusregaud.fr [Radiation Oncology Department, Institut Claudius Regaud, Toulouse (France); Filleron, Thomas; Graff, Pierre [Radiation Oncology Department, Institut Claudius Regaud, Toulouse (France); Jonca, Frédéric [Department of Urology, Clinique Ambroise Paré, Toulouse (France); Huyghe, Eric; Thoulouzan, Matthieu; Soulie, Michel; Malavaud, Bernard [Department of Urology and Andrology, CHU Rangueil, Toulouse (France); Aziza, Richard; Brun, Thomas; Delannes, Martine; Bachaud, Jean-Marc [Radiation Oncology Department, Institut Claudius Regaud, Toulouse (France)

    2013-11-15

    Purpose: To review the clinical outcome of I-125 permanent prostate brachytherapy (PPB) for low-risk and intermediate-risk prostate cancer and to compare 2 techniques of loose-seed implantation. Methods and Materials: 574 consecutive patients underwent I-125 PPB for low-risk and intermediate-risk prostate cancer between 2000 and 2008. Two successive techniques were used: conventional implantation from 2000 to 2004 and automated implantation (Nucletron, FIRST system) from 2004 to 2008. Dosimetric and biochemical recurrence-free (bNED) survival results were reported and compared for the 2 techniques. Univariate and multivariate analysis researched independent predictors for bNED survival. Results: 419 (73%) and 155 (27%) patients with low-risk and intermediate-risk disease, respectively, were treated (median follow-up time, 69.3 months). The 60-month bNED survival rates were 95.2% and 85.7%, respectively, for patients with low-risk and intermediate-risk disease (P=.04). In univariate analysis, patients treated with automated implantation had worse bNED survival rates than did those treated with conventional implantation (P<.0001). By day 30, patients treated with automated implantation showed lower values of dose delivered to 90% of prostate volume (D90) and volume of prostate receiving 100% of prescribed dose (V100). In multivariate analysis, implantation technique, Gleason score, and V100 on day 30 were independent predictors of recurrence-free status. Grade 3 urethritis and urinary incontinence were observed in 2.6% and 1.6% of the cohort, respectively, with no significant differences between the 2 techniques. No grade 3 proctitis was observed. Conclusion: Satisfactory 60-month bNED survival rates (93.1%) and acceptable toxicity (grade 3 urethritis <3%) were achieved by loose-seed implantation. Automated implantation was associated with worse dosimetric and bNED survival outcomes.

  7. 直肠癌术前容积调强与固定野调强技术的剂量学比较%Dosimetric Comparison between Preoperative Volumetric Modulated Arc Therapy and Fixed-field Intensity-modulated Radiotherapy for Rectal Cancer

    Institute of Scientific and Technical Information of China (English)

    杨波; 庞廷田; 孙显松; 胡克; 邱杰; 张福泉

    2014-01-01

    Objective To compare the dosimetric characteristics of preoperative volumetric modulated arc therapy ( VMAT) and fixed-field intensity-modulated radiotherapy ( FF-IMRT) for rectal cancer .Methods The CT images of 15 patients with rectal cancer were transferred into Eclipse planning system .FF-IMRT and VMAT plans were optimized on an Eclipse treatment planning system using beam data generated for Varian Trilogy linear accelerator .Same institutional dose-volume constraints for rectal cancer were used in both techniques .Targets and organs at risk were evaluated .Results The target volume coverage could meet the requirement of described dosage in both VMAT plan group and FF-IMRT plan group .Compared with the FF-IMRT plan group , the plan-ning target volume ( PTV) 105% ( PTV105%) coverage, Dmean, and Dmax significantly increased in the VMAT plan group ( P=0.011, P=0.017, and P=0.006, respectively), the radiation conformity index (CI) significantly decreased ( P=0.008 ) , and the homogeneity index showed no significant difference ( P=0.193 ) . Compared with the FF-IMRT plan group , the V50 of the bladder in the VMAT plan group was increased by about 15%( P=0.009 ) , and the Dmax increased by 0.7 Gy ( P=0.003 );the V30 of the small intestine decreased by 10% (P=0.004), and the Dmax was increased by 0.9 Gy (P=0.000); the V10, V30, and V40 of the bone marrow reduced by 2%, 10%, and 10%( P=0.000 , P=0.000 , and P=0.000 ) , and the Dmean re-duced by 1.7 Gy ( P=0.000 );the D5 of the left and right femoral heads reduced by 3.2 Gy and 2.4 Gy ( P=0.000 , P=0.000 ); the V10 , V20 , V30 , and V40 of the body also significantly decreased ( P=0.003 , P=0.000 , P=0.000 , and P=0.004 ) .The VMAT group also had significantly lower number of monitor units ( MU) when compared with the FF-IMRT plan group ( P=0.000 ) .Conclusions In patients with rectal canc-er, preoperative VMAT can achieve equivalent or superior dose distribution compared with the FF -IMRT.In addi-tion, VMAT can

  8. Correlation of dosimetric parameters obtained with the analytical anisotropic algorithm and toxicity of chest chemoradiation in lung carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Cartier, Lysian; Auberdiac, Pierre; Khodri, Mustapha; Malkoun, Nadia [Departement de Radiotherapie, Institut de Cancerologie de la Loire, St-Priest en Jarez (France); Chargari, Cyrus [Service d' Oncologie Radiotherapie, Hopital d' Instruction des Armees du Val-de-Grace, Paris (France); Thorin, Julie [Departement de Sante Publique, Unite de Statistique, Institut de Cancerologie de la Loire, St-Priest en Jarez (France); Melis, Adrien [Departement d' Oncologie Medicale, Institut de Cancerologie de la Loire, St-Priest en Jarez (France); Talabard, Jean-Noeel; Laroche, Guy de [Departement de Radiotherapie, Institut de Cancerologie de la Loire, St-Priest en Jarez (France); Fournel, Pierre [Departement d' Oncologie Medicale, Institut de Cancerologie de la Loire, St-Priest en Jarez (France); Tiffet, Olivier [Service de Chirurgie Thoracique, Centre Hospitalier Universitaire de Saint Etienne, Saint Etienne (France); Schmitt, Thierry [Departement de Radiotherapie, Institut de Cancerologie de la Loire, St-Priest en Jarez (France); and others

    2012-07-01

    The purpose of this study was to analyze and revisit toxicity related to chest chemoradiotherapy and to correlate these side effects with dosimetric parameters obtained using analytical anisotropic algorithm (AAA) in locally unresectable advanced lung cancer. We retrospectively analyzed data from 47 lung cancer patients between 2005 and 2008. All received conformal 3D radiotherapy using high-energy linear accelerator plus concomitant chemotherapy. All treatment planning data were transferred into Eclipse 8.05 (Varian Medical Systems, Palo Alto, CA) and dosimetric calculations were performed using AAA. Thirty-three patients (70.2%) developed acute pneumopathy after radiotherapy (grades 1 and 2). One patient (2.1%) presented with grade 3 pneumopathy. Thirty-one (66%) presented with grades 1-2 lung fibrosis, and 1 patient presented with grade 3 lung fibrosis. Thirty-four patients (72.3%) developed grade 1-2 acute oesophagic toxicity. Four patients (8.5%) presented with grades 3 and 4 dysphagia, necessitating prolonged parenteral nutrition. Median prescribed dose was 64 Gy (range 50-74) with conventional fractionation (2 Gy per fraction). Dose-volume constraints were respected with a median V20 of 23.5% (maximum 34%) and a median V30 of 17% (maximum 25%). The median dose delivered to healthy contralateral lung was 13.1 Gy (maximum 18.1 Gy). At univariate analysis, larger planning target volume and V20 were significantly associated with the probability of grade {>=}2 radiation-induced pneumopathy (p = 0.022 and p = 0.017, respectively). No relation between oesophagic toxicity and clinical/dosimetric parameters could be established. Using AAA, the present results confirm the predictive value of the V20 for lung toxicity as already demonstrated with the conventional pencil beam convolution approach.

  9. Predictive dosimetric parameters for gastrointestinal toxicity with hypofractioned radiotherapy in pancreatic adenocarcinoma

    Directory of Open Access Journals (Sweden)

    Liu X

    2016-04-01

    Full Text Available Xian Liu,* Gang Ren,* Liqin Li, Tingyi Xia Department of Radiation Oncology, Air Force General Hospital, Beijing, People’s Republic of China *These authors contributed equally to this work Abstract: To better guide the development and optimization of radiotherapy planning, to reduce the incidence of radiation reactions, and to improve the quality of life of the patients with pancreatic cancer using radiotherapy, we conducted this study to explore the dosimetric parameters that predict the risk of gastrointestinal (GI toxicity with hypofractioned radiotherapy for pancreatic cancer. Between January 2014 and January 2015, the medical records of 68 patients with pancreatic cancer who underwent helical tomotherapy at the Air Force General Hospital were analyzed. The doses delivered to the planning target volume, clinical target volume, and gross tumor volume–internal gross tumor volume of the primary pancreatic lesions were 50, 60, and 70–80 Gy in 15–20 fractions, respectively. GI toxicity was scored according to version 4.0 of the National Cancer Institute Common Terminology Criteria for Adverse Events. The stomach and duodenum were contoured separately to determine the dose–volume histogram parameters. Univariate and multivariate analyses were adopted to identify clinical and physical risk factors associated with GI toxicity. The median follow-up was 9 months (range: 4–16 months. Eighteen patients had grade II acute GI toxicity, one patient had grade III acute GI toxicity, 17 patients had grade II late GI toxicity, and one patient had grade III late GI toxicity. On univariate analysis, the volume, the average dose Dmean, the maximum dose to 1, 3, 5, and 10 cm3 of the stomach and duodenum (D1, D3, D5, and D10, and the relative volumes receiving 5–40 Gy (V5–V40, and the absolute volumes receiving 5–45 Gy (aV5–aV45 of the duodenum were significantly associated with grade II or higher GI toxicity (P<0.05. On multivariate

  10. 直肠癌术前容积旋转调强放疗和五野静态调强放疗的剂量学比较%Dosimetric comparison between preoperative volumetric modulated arc therapy and five-field intensity modulated radiotherapy for rectal cancer

    Institute of Scientific and Technical Information of China (English)

    汪琳; 张红雁; 钱立庭; 吴爱东; 方为; 闫冰

    2016-01-01

    目的:比较直肠癌术前患者应用五野静态调强放疗(5F-IMRT)和容积弧形调强放疗( VMAT)两种计划的剂量学差别。方法分别将16例术前行同期放化疗的直肠癌患者进行5F-IMRT和VMAT两种计划设计,应用剂量体积直方图比较分析靶区和危及器官的剂量学差异及治疗参数。结果两种治疗计划均能满足临床剂量要求。5F-IMRT计划的适形指数(CI)为0.88±0.04,VMAT计划的CI为0.90±0.03,两种计划均能很好满足95%等剂量曲线对100%PTV体积的完全覆盖;VMAT 和 IMRT 计划的均匀性指数(HI)分别为1.06±0.01和1.05±0.01,差异无统计学意义(t=1.37,P>0.05)。5F-IMRT和VMAT计划中重要的危及器官如小肠、膀胱和股骨头等的关键剂量评价指标( Dmean、Dmax)及受照射体积的关键评价指标( V20、V30、V40和V50)在两种放疗计划中差异无统计学意义( P >0.05)。VMAT计划组较5F-IMRT计划组机器跳数( MU)平均值减少39%(P=0.000)。结论直肠癌术前放疗中采用VMAT技术可获得等同于5F-IMRT计划的剂量分布,危及器官均能得到较好的保护, VMAT计划MU明显降低,治疗时间明显缩短。%Objective To compare the dosimetric characteristics of volumetric modulated arc therapy( VMAT) and five-field intensity modulated radiotherapy(5F-IMRT) in preoperative radiotherapy for rectal cancer. Methods Six-teen patients with rectal cancer who underwent preoperative chemo-radiotherapy were enrolled in this study. VMAT and 5F-IMRT plans were designed for each patient. The dose distribution in target volumes and organs at risk was e-valuated according to the dose-volume histogram. Results Both plans could meet target dose specifications and nor-mal tissue constraint. The CI was similar between the 5F-IMRT(0. 88 ± 0. 04) and VMAT plans (0. 90 ± 0. 03), which could satisfy 95% of prescribed dose for covered PTV. The HI of the VMAT plan was 1. 06 ± 0. 01 compared to 1. 05 ± 0. 01

  11. A dosimetric study of supine and prone treatment setups for breast cancer patients after breast conserving surgery%早期乳腺癌保乳术后仰卧及俯卧位调强放疗的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    铁剑; 张健; 张艺宝; 吴昊

    2014-01-01

    目的 比较早期乳腺癌保乳术后仰卧位与俯卧位调强治疗计划靶区和危及器官的剂量学差异.方法 选取15例接受保乳术后放疗的大乳腺及乳腺下垂的左侧乳腺癌患者,分别进行仰卧位及俯卧位CT定位扫描,利用相同优化条件分别进行切线2野调强治疗计划设计.比较2种不同体位计划的靶区剂量分布、心脏、左肺及右侧乳腺受照剂量和体积,以及机器跳数的差异.结果 俯卧位调强计划适形度指数(CI)优于仰卧位计划(0.79±0.05 vs.0.72 ±0.04,W=138,P<0.01),均匀性指数(HI)也优于仰卧位计划(1.09 ±0.01 vs.1.12±0.02,t=-4.7,P<0.01).俯卧位计划靶区接受95%处方剂量照射的百分体积(V95%)、最小剂量(Dmin)大于仰卧位计划(t=7.1、6.4,P<0.01),平均剂量(Dmean)大于仰卧位计划(W=153,P<0.01),最大剂量(Dmax)小于仰卧位计划(t=-3.6,P<0.01).仰卧位计划的右乳接受5 Gy照射的百分体积(V5)小于俯卧位计划(W=160,P<0.01),心脏接受30 Gy照射的百分体积(V30)大于俯卧位计划(t=5.4,P<0.01),心脏平均剂量(Dmean)、左肺接受20和5 Gy照射的百分体积(V20、V5)明显大于俯卧位计划(W=133、120、120,P<0.01).机器跳数间差异无统计学意义.结论 对于大乳腺及乳腺下垂乳腺癌患者,保乳术后俯卧位调强计划与仰卧位调强计划相比,靶区剂量分布更均匀,心、肺受照射剂量和体积明显减少.%Objective To compare the dosimetric differences of the targets and organs at risk (OARs) for early stage breast cancer patients receiving intensity modulated radiotherapy (IMRT) with supine or prone setups after breast conserving surgery.Methods After breast conserving surgery,15 left breast cancer patients with large and pendulous breasts were selected.Their planning CT images were acquired with supine and prone orientations respectively,based on which IMRT plans of 2 tangential fields were developed using the same optimization

  12. Transformation of Physical DVHs to Radiobiologically Equivalent Ones in Hypofractionated Radiotherapy Analyzing Dosimetric and Clinical Parameters: A Practical Approach for Routine Clinical Practice in Radiation Oncology

    Directory of Open Access Journals (Sweden)

    Zoi Thrapsanioti

    2013-01-01

    Full Text Available Purpose. The purpose of this study was to transform DVHs from physical to radiobiological ones as well as to evaluate their reliability by correlations of dosimetric and clinical parameters for 50 patients with prostate cancer and 50 patients with breast cancer, who were submitted to Hypofractionated Radiotherapy. Methods and Materials. To achieve this transformation, we used both the linear-quadratic model (LQ model and the Niemierko model. The outcome of radiobiological DVHs was correlated with acute toxicity score according to EORTC/RTOG criteria. Results. Concerning the prostate radiotherapy, there was a significant correlation between RTOG acute rectal toxicity and ( and ( dosimetric parameters, calculated for  Gy. Moreover, concerning the breast radiotherapy there was a significant correlation between RTOG skin toxicity and dosimetric parameter, calculated for both  Gy ( and  Gy (. The new tool seems reliable and user-friendly. Conclusions. Our proposed model seems user-friendly. Its reliability in terms of agreement with the presented acute radiation induced toxicity was satisfactory. However, more patients are needed to extract safe conclusions.

  13. Dosimetric comparison between model 9011 and 6711 sources in prostate implants

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Hualin, E-mail: zhang248@iupui.edu [Department of Radiation Oncology, Indiana University School of Medicine, Indianapolis, IN (United States); Arizona Oncology Services, Phoenix, AZ (United States); Beyer, David [Arizona Oncology Services, Phoenix, AZ (United States)

    2013-07-01

    The purpose of this work is to evaluate the model 9011 iodine-125 ({sup 125}I) in prostate implants by comparing dosimetric coverage provided by the 6711 vs 9011 source implants. Postimplant dosimetry was performed in 18 consecutively implanted patients with prostate cancer. Two were implanted with the 9011 source and 16 with the 6711 source. For purposes of comparison, each implant was then recalculated assuming use of the other source. The same commercially available planning system was used and the specific source data for both 6711 and 9011 products were entered. The results of these calculations are compared side by side in the terms of the isodose values covering 100% (D100) and 90% (D90) of prostate volume, and the percentages of volumes of prostate, bladder, rectum, and urethra covered by 200% (V200), 150% (V150), 100% (V100), 50% (V50), and 20% (V20) of the prescribed dose as well. The 6711 source data overestimate coverage by 6.4% (ranging from 4.9% to 6.9%; median 6.6%) at D100 and by 6.6% (ranging from 6.2% to 6.8%; median 6.6%) at D90 compared with actual 9011 data. Greater discrepancies of up to 67% are seen at higher dose levels: average reduction for V100 is 2.7% (ranging from 0.6% to 7.7%; median 2.3%), for V150 is 14.6% (ranging from 6.1% to 20.5%; median 15.3%), for V200 is 14.9% (ranging from 4.8% to 19.1%; median 16%); similarly seen in bladder, rectal, and urethral coverage. This work demonstrates a clear difference in dosimetric behavior between the 9011 and 6711 sources. Using the 6711 source data for 9011 source implants would create a pronounced error in dose calculation. This study provides evidence that the 9011 source can provide the same dosimetric quality as the 6711 source, if properly used; however, the 6711 source data should not be considered as a surrogate for the 9011 source implants.

  14. Dosimetric effect on pediatric conformal treatment plans using dynamic jaw with Tomotherapy HDA

    Energy Technology Data Exchange (ETDEWEB)

    Han, Eun Young, E-mail: eyhan@uams.edu [Department of Radiation Oncology, University of Arkansas Medical Sciences, Little Rock, AR (United States); Kim, Dong-Wook [Department of Radiation Oncology, Kyung Hee University Hospital, Seoul (Korea, Republic of); Zhang, Xin; Penagaricano, Jose; Liang, Xiaoying; Hardee, Matthew; Morrill, Steve; Ratanatharathorn, Vaneerat [Department of Radiation Oncology, University of Arkansas Medical Sciences, Little Rock, AR (United States)

    2015-10-01

    It is important to minimize the radiation dose delivered to healthy tissues in pediatric cancer treatment because of the risk of secondary malignancies. Tomotherapy HDA provides a dynamic jaw (DJ) delivery mode that creates a sharper penumbra at the craniocaudal ends of a target in addition to a fixed jaw (FJ) delivery mode. The purpose of this study was to evaluate its dosimetric effect on the pediatric cancer cases. We included 6 pediatric cases in this study. The dose profiles and plan statistics—target dose conformity, uniformity, organ-at-risk (OAR) mean dose, beam-on time, and integral dose—were compared for each case. Consequently, the target dose coverage and uniformity were similar for different jaw settings. The OAR dose sparing depended on its relative location to the target and disease sites. For example, in the head and neck cancer cases, the brain stem dose using DJ 2.5 was reduced by more than two-fold (2.4 Gy vs. 6.3 Gy) than that obtained with FJ 2.5. The integral dose with DJ 2.5 decreased by more than 9% compared with that with FJ 2.5. Thus, using dynamic jaw in pediatric cases could be critical to reduce a probability of a secondary malignancy.

  15. DARTAB: a program to combine airborne radionuclide environmental exposure data with dosimetric and health effects data to generate tabulations of predicted health impacts

    Energy Technology Data Exchange (ETDEWEB)

    Begovich, C.L.; Eckerman, K.F.; Schlatter, E.C.; Ohr, S.Y.; Chester, R.O.

    1981-08-01

    The DARTAB computer code combines radionuclide environmental exposure data with dosimetric and health effects data to generate tabulations of the predicted impact of radioactive airborne effluents. DARTAB is independent of the environmental transport code used to generate the environmental exposure data and the codes used to produce the dosimetric and health effects data. Therefore human dose and risk calculations need not be added to every environmental transport code. Options are included in DARTAB to permit the user to request tabulations by various topics (e.g., cancer site, exposure pathway, etc.) to facilitate characterization of the human health impacts of the effluents. The DARTAB code was written at ORNL for the US Environmental Protection Agency, Office of Radiation Programs.

  16. Dosimetric Comparison in Breast Radiotherapy of 4 MV and 6 MV on Physical Chest Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Donato da Silva, Sabrina; Passos Ribeiro Campos, Tarcisio [Nuclear Engineering Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Batista Nogueira, Luciana [Anatomy and Imaging Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Lima Souza Castro, Andre [Nuclear Engineering Department, Federal University of Minas Gerais, Belo Horizonte (Brazil); Institute of Radiation San Francisco, Belo Horizonte (Brazil); Alves de oliveira, Marcio; Galvao Dias, Humberto [Cancer Hospital in Uberlandia, Uberlandia (Brazil)

    2015-07-01

    According to the World Health Organization (2014) breast cancer is the main cause of death by cancer in women worldwide. The biggest challenge of radiotherapy in the treatment of cancer is to deposit the entire prescribed dose homogeneously in the breast, sparing the surrounding tissue. In this context, this paper aimed at evaluating and comparing internal dose distribution in the mammary gland based on experimental procedures submitted to two distinct energy spectra produced in breast cancer radiotherapy. The methodology consisted of reproducing opposite parallel fields used in the treatment of breast tumors in a chest phantom. This simulator with synthetic breast, composed of equivalent tissue material (TE), was previously developed by the NRI Research Group (UFMG). The computer tomography (CT) scan of the simulator was obtained antecedently. The radiotherapy planning systems (TPS) in the chest phantom were performed in the ECLIPSE system from Varian Medical Systems and CAT 3D system from MEVIS. The irradiations were reproduced in the Varian linear accelerator, model SL- 20 Precise, 6 MV energy and Varian linear accelerator, 4 MV Clinac 6x SN11 model. Calibrations of the absorbed dose versus optical density from radiochromic films were generated in order to obtain experimental dosimetric distribution at the films positioned within the glandular and skin equivalent tissues of the chest phantom. The spatial dose distribution showed equivalence with the TPS on measurement data performed in the 6 MV spectrum. The average dose found in radiochromic films placed on the skin ranged from 49 to 79%, and from 39 to 49% in the mammary areola, for the prescribed dose. Dosimetric comparisons between the spectra of 4 and 6 MV, keeping the constant geometry of the fields applied in the same phantom, will be presented showing their equivalence in breast radiotherapy, as well as the variations will be discussed. To sum up, the dose distribution has reached the value expected in

  17. Incorrect dosimetric leaf separation in IMRT and VMAT treatment planning

    DEFF Research Database (Denmark)

    Sjölin, Maria; Edmund, Jens Morgenthaler

    2016-01-01

    PURPOSE: Dynamic treatment planning algorithms use a dosimetric leaf separation (DLS) parameter to model the multi-leaf collimator (MLC) characteristics. Here, we quantify the dosimetric impact of an incorrect DLS parameter and investigate whether common pretreatment quality assurance (QA) methods....... Pretreatment verification QA was performed with a bi-planar diode array phantom and the electronic portal imaging device (EPID). Measurements were compared to the correct and incorrect planned doses using gamma evaluation with both global (G) and local (L) normalization. Correlation, specificity...... was observed. Optimal gamma settings with 3%L/3mm (per beam and composite plan) and 3%G/2mm (composite plan) for the diode array phantom and 2%G/2mm (composite plan) for the EPID system were found. Global normalization and per beam ROC analysis of the diode array phantom showed an area under the curve

  18. Clinical and dosimetric factors of radiation-induced esophageal injury: Radiation-induced esophageal toxicity

    Institute of Scientific and Technical Information of China (English)

    Wen-Bo Qiao; Yan-Hui Zhao; Yan-Bin Zhao; Rui-Zhi Wang

    2005-01-01

    AIM: To analyze the clinical and dosimetric predictive factors for radiation-induced esophageal injury in patients with non-small-cell lung cancer (NSCLC) during threedimensional conformal radiotherapy (3D-CRT). METHODS: We retrospectively analyzed 208 consecutive patients (146 men and 62 women) with NSCLC treated with 3D-CRT. The median age of the patients was 64 years (range 35-87 years). The clinical and treatment parameters including gender, age, performance status, sequential chemotherapy, concurrent chemotherapy, presence of carinal or subcarinal lymph 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 were studied. Clinical and dosimetric factors for radiation-induced acute and late grade 3-5 esophageal injury were analyzed according to Radiation Therapy Oncology Group (RTOG) criteria.RESULTS: Twenty-five (12%) of the two hundred and eight patients developed acute or late grade 3-5 esophageal injury. Among them, nine patients had both acute and late grade 3-5 esophageal injury, two died of late esophageal perforation. Concurrent chemotherapy and maximal point dose to the esophagus ≥60 Gy were significantly associated with the risk of grade 3-5 esophageal injury. Fifty-four (26%) of the two hundred and eight patients received concurrent chemotherapy. Among them, 25 (46%) developed grade 3-5 esophageal injury (P = 0.0001<0.01). However, nograde 3-5 esophageal injury occurred in patients who received a maximal point dose to the esophagus <60 Gy (P= 0.0001<0.01).CONCLUSION: Concurrent chemotherapy and the maximal esophageal point dose ≥60 Gy are significantly associated with the risk of grade 3-5 esophageal injury in patients with NSCLC treated with 3D-CRT.

  19. Correlation of Clinical and Dosimetric Factors With Adverse Pulmonary Outcomes in Children After Lung Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Venkatramani, Rajkumar, E-mail: rvenkatramani@chla.usc.edu [Division of Hematology/Oncology, Children' s Hospital Los Angeles, Los Angeles, California (United States); Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California (United States); Kamath, Sunil [Department of Pulmonology, Children' s Hospital Los Angeles, Los Angeles, California (United States); Wong, Kenneth [Division of Hematology/Oncology, Children' s Hospital Los Angeles, Los Angeles, California (United States); Olch, Arthur J. [Division of Hematology/Oncology, Children' s Hospital Los Angeles, Los Angeles, California (United States); Department of Radiation Oncology, University of Southern California, Los Angeles, California (United States); Malvar, Jemily [Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (United States); Sposto, Richard [Division of Hematology/Oncology, Children' s Hospital Los Angeles, Los Angeles, California (United States); Department of Preventive Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California (United States); Goodarzian, Fariba [Department of Radiology, Children' s Hospital Los Angeles, Los Angeles, California (United States); Freyer, David R. [Division of Hematology/Oncology, Children' s Hospital Los Angeles, Los Angeles, California (United States); Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California (United States); Keens, Thomas G. [Department of Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, California (United States); Department of Pulmonology, Children' s Hospital Los Angeles, Los Angeles, California (United States); and others

    2013-08-01

    Purpose: To identify the incidence and the risk factors for pulmonary toxicity in children treated for cancer with contemporary lung irradiation. Methods and Materials: We analyzed clinical features, radiographic findings, pulmonary function tests, and dosimetric parameters of children receiving irradiation to the lung fields over a 10-year period. Results: We identified 109 patients (75 male patients). The median age at irradiation was 13.8 years (range, 0.04-20.9 years). The median follow-up period was 3.4 years. The median prescribed radiation dose was 21 Gy (range, 0.4-64.8 Gy). Pulmonary toxic chemotherapy included bleomycin in 58.7% of patients and cyclophosphamide in 83.5%. The following pulmonary outcomes were identified and the 5-year cumulative incidence after irradiation was determined: pneumonitis, 6%; chronic cough, 10%; pneumonia, 35%; dyspnea, 11%; supplemental oxygen requirement, 2%; radiographic interstitial lung disease, 40%; and chest wall deformity, 12%. One patient died of progressive respiratory failure. Post-irradiation pulmonary function tests available from 44 patients showed evidence of obstructive lung disease (25%), restrictive disease (11%), hyperinflation (32%), and abnormal diffusion capacity (12%). Thoracic surgery, bleomycin, age, mean lung irradiation dose (MLD), maximum lung dose, prescribed dose, and dosimetric parameters between V{sub 22} (volume of lung exposed to a radiation dose ≥22 Gy) and V{sub 30} (volume of lung exposed to a radiation dose ≥30 Gy) were significant for the development of adverse pulmonary outcomes on univariate analysis. MLD, maximum lung dose, and V{sub dose} (percentage of volume of lung receiving the threshold dose or greater) were highly correlated. On multivariate analysis, MLD was the sole significant predictor of adverse pulmonary outcome (P=.01). Conclusions: Significant pulmonary dysfunction occurs in children receiving lung irradiation by contemporary techniques. MLD rather than prescribed

  20. Dosimetric study on intensity-modulated radiotherapy plans -based on kilo-voltage cone beam computed tomography images from left-sided breast cancer patients receiving modified radical mastectomy%放疗过程中剂量学变化研究--基于 KV-CBCT 左侧乳腺癌根治术后图像

    Institute of Scientific and Technical Information of China (English)

    朱小杨; 王明

    2015-01-01

    The aim is to investigate the dosimetric characteristics of planning target volume (PTV) and organs at risk (OAR) during the radiotherapy of left-sided breast cancer treated with modified radical mastectomy by comparing IMRT plans based on CT images and kilo-voltage cone beam computed tomography (KV-CBCT) images. 18 patients with left-sided breast cancer treated with radical mastectomy were selected. Treatment plans (PCT) based on CT images were designed and performed. KV-CBCT images were also acquired on the 1st day, 6th day, 11th day, 16th day, and 21st day of radiotherapy. All structures on planning CT images including PTV and OAR were applied by bulk density assignment (BDA) and plan parameters of PCT were replanted to a copy of planning CT images, which generated a new plan (PBDA). The prescription dose of PBDA was 50 Gy with conventional fractionation: 2 Gy per fraction, 5 fractions per week, total 25 fractions. The prescription dose was 50 Gy/25 F/5 week, 90% of the target area were covered by the prescription dose. The 5 series of KV-CBCT images acquired were imported into the planning system and matched with the planning CT for the same treatment position. The same structures of planning CT images were copied and applied by BDA on 5 series of KV-CBCT images. 5 replanted plans (PREP) and 5 new KV-CBCT plans (PCBCT) were designed based on these KV-CBCT images. Radiation parameters of PREP were same to those of PCT, but all parameters of PCBCT were new. 5 Gy given to each PREPand PCBCT covered 90% PTV. Two composite plans (P∑REPand P∑CBCT)were compounded of the fivePREPs and five PCBCTs, respectively. Total prescription dose of P∑REP and P∑CBCTwere 50 Gy/25 F/5 week. According to dose volume histograms (DVHs), dose distribution of PCT, PBDA, P∑REPandP∑CBCT were compared and analyzed byt-test. The results showed that PBDAhas similar conform index (CI) and inhomogeneity coefficient (HI) to PCT(p>0.05). HI and CI of P∑REPwere significantly worse

  1. Dosimetric comparison of volumetric modulated arc therapy for rectal cancer using flattening filter-free and flattening filter modes%直肠癌有无均整器模式下容积旋转调强放疗的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    张基永; 陆佳扬; 吴丽丽; 马长春; 张武哲

    2015-01-01

    Objective To compare the dosimetric differences of volumetric modulated arc therapy (VMAT) for preoperative radiotherapy of rectal cancer using 6MV X-ray flattening filter-free (FFF) and flattening filter (FF) modes.Methods FF-VMAT and FFF-VMAT plans were designed for 15 rectal cancer patients with preoperative radiotherapy by planning treatment system (Eclipse 10.0),respectively.Prescription dose of PTV was 50 Gy in 25 fractions.When the plans were normalized to 50 Gy to 95 % of PTV,the dose volume histogram (DVH),target and risk organ doses,conformity indexes (CI),homogeneity indexes (HI),low dose volume of normal tissue (B-P),monitor units (MU) and treatment time (TT) were compared between the two kinds of plans.Results FF-VMAT provided the lower Dmean,V105,HI (P < 0.05),and higher CI (P < 0.05) compared with FFF-VMAT.Small intestine (D5),Bladder (D5,Dmean V40,V50),L-femoral head (V40),R-femoral head (Dmean) were lower in FF-VMAT than those in FFF-VMAT (P < 0.05).FF-VMAT had higher B-P (V5) compared with FFF-VMAT (P < 0.05).FF-VMAT reduced the monitor units (MU) by 21% (382±53 vs 483±26,P < 0.05),as well as the treatment time (TT) in FF-VMAT was no significant difference compared with that in FFF-VMAT [(148±4) s vs (146±3) s,P > 0.05)].Conclusions The qualities of FF-VMAT and FFF-VMAT plans were comparable and both clinically acceptable.When comparing two plans,FF-VMAT showed better target coverage and some of OARs sparing.The MUs of FFF-VMAT were higher than those of FF-VMAT,yet were not delivered within the same time.%目的 比较TrueBeam直线加速器6MVX射线均整模式(FF)和非均整模式(FFF)下容积旋转调强放疗(VMAT)在直肠癌术前放疗中的剂量学差异.方法 选取15例直肠癌术前患者,在Eclipse 10.0计划系统上分别进行FF-VMAT和FFF-VMAT计划设计.计划靶体积(PTV)处方剂量为50 Gy/25次,2 Gy/次.在95%的PTV达到处方剂量前提下,比较两种计划的剂量体积直方图(DVH)、靶

  2. Dosimetric comparison between volumetric modulated arc therapy and fixed-gantry dynamic intensity modulated radiation therapy for rectal cancer radiotherapy%直肠癌旋转容积调强与固定野动态调强的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    花威; 李军; 谭飞; 陈婷婷; 汪步海

    2012-01-01

    目的:比较旋转容积调强(VMAT)与固定野动态调强(dIMRT)在直肠癌放疗计划中的剂量学差异.方法:8例直肠癌患者利用瓦里安计划系统(Eclipse 8.6)分别进行VMAT和dIMRT放射治疗计划设计.利用剂量体积直方图来比较两种计划中靶区和危及器官的剂量学差异.结果:与dIMRT相比,VMAT靶区适合度指数(CI)、靶区剂量均匀性指数(HI)均更接近1,Dmin为(43.403±0.486)Gy,更接近处方剂量,差异有统计学意义,P<0.05.在VMAT计划中小肠的D30%、D50%和Dmean分别为(25.918±1.216)、(22.340士3.784)和(23.547±2.863) Gy,低于dIMRT计划的(28.073±3.114)、(24.172±2.540)和(25.257±1.374) Gy,P值分别为0.00、0.01和0.00;膀胱的D30%为(35.380±2.734) Gy,较dIMRT的(30.123±2.209) Gy偏高,P=0.00,但仍远低于剂量限值;股骨头的D5%和Dmean分别为(31.344±3.556)和(20.179±3.017) Gy,显著高于dIMRT计划的(26.731±2.828)和(17.459±3.279) Gy,P值均为0.00.VMAT总MU减少52.7%,治疗时间仅为dIMRT的1/4.结论:VMAT计划可以达到或优于dIMRT计划的靶区剂量分布,能更好地降低部分危及器官的受照剂量,并且具有较少总MU、总治疗时间的优势,减少了治疗中不确定性因素的影响及患者不适感.%OBJECTIVE: To compare the dosimetric difference between volumetric modulated arc therapy(VMAT) and fixed-gantry dynamic intensity modulated radiation therapy(dIMRT) for rectal cancer. METHODS: VMAT and dlM-RT treatment plans of 8 rectal cancer cases were generated by Vrian Eclipse ver8. 6 treatment planning systerm. Dose volume histograms were used to compare the target volume and organs at risks. RESULTS: Compared to dIMRT,conformity index(CI) and homogeneity index(HI) of VMAT closer to one. Dmin of VMAT was (43. 403 ± 0. 486) Gy,closer to prescription dose. There were significant differences in CI,HI and Dmin(P<0. 05). The small intestinal's D30% ,D50% and Dmean were larger in dIMRT than those in VAMT(P values were

  3. Comparison of dosimetric parameter and adverse reaction analysis in different radiation technology in the patients received modi-fied radical mastectomy for breast cancer%乳腺癌改良根治术后不同放疗技术的剂量学比较及不良反应观察

    Institute of Scientific and Technical Information of China (English)

    王承伟; 许刚; 薛辉; 张良

    2016-01-01

    Objective: To compare dosimetric difference and acute adverse reactions between 3 different radiotherapy plan in pa⁃tients who received modified radical mastectomy for breast cancer. Methods:30 cases of modified radical mastectomy of breast cancer pa⁃tients were left after the design of volumetric modulated arc (VMAT), intensity-modulated (IMRT) and three-dimensional conformal radiother⁃apy (3D-CRT), were randomly divided into VMAT, IMRT and 3D-CRT group, each group of 10 cases, radiotherapy according to the prescrip⁃tion dose of 50 Gy The dose volume histogram (DVH) analysis was used to evaluate the dose parameters of planning target volume (PTV) , the treatment time in each time. V5, V10, V20, Dmean in left lung, V30, V40, and Dmeanof heart were compared between 3 groups. Acute radiation skin reaction, lung injury was evaluated. The changes of cardiac TroponinI was used to evaluate cardiac injury.Results:All of the evaluation indexes except for HI of 3D-CRT PTVwere inferior to VMAT and IMRT (P2, 30.05).Conclusion:The dose distribution and uniformity in VMAT and IMRT were better than that in 3D-CRT, and VMAT has obvious advantage in target volume dose coverage and fraction treatment time than other 2 groups, VMAT and IMRT can effec⁃tively reduce the high dose area volume and average dose of OAR, reduce the incidence of acute adverse reactions such as skin damage, heart damage and so on.%目的:比较乳腺癌改良根治术后3种不同放疗计划的剂量学差异和急性不良反应。方法:将30例左侧乳腺癌改良根治术后患者分别设计容积旋转调强(VMAT)、固定野调强(IMRT)和三维适形放疗(3D-CRT)计划,随机分成VMAT、IMRT和3D-CRT组,各10例,按处方剂量50 Gy进行放射治疗。利用剂量体积直方图(DVH)分析评价PTV的剂量参数,比较患侧肺V5、V10、V20、Dmean,心脏V30、V40、Dmean。评价急性放射性皮肤反应、肺损伤。以心肌肌钙蛋白Ⅰ

  4. 直肠癌术前五野静态调强和容积弧形调强放疗剂量学的比较研究%Dosimetric comparison between preoperative five-field intensity modulated radiotherapy and volumetric modulated arc therapy in the treatment of rectum cancer

    Institute of Scientific and Technical Information of China (English)

    叶序卷; 高远红; 陈利; 杜乐辉; 张广顺; 贾钰铭; 雷开键; 刘孟忠

    2012-01-01

    目的 探讨直肠癌术前五野静态调强(5 F-IMRT)和容积弧形调强(VMAT)放疗计划的剂量学特点.方法 应用CMS monaco治疗计划系统分别对23例术前同期放化疗的直肠癌患者行5F-IMRT和VMAT放疗计划设计,比较两种放疗技术的靶区剂量分布特点以及小肠、膀胱、双侧股骨头等正常组织的受照射剂量及体积.结果 5F-IMRT计划的适形指数(CI)为0.810±0.043,VMAT计划的CI为0.822±0.062,两者均能很好满足95%等剂量曲线对100% PTV体积的完全覆盖;5F-IMRT计划中GTV、CTV和PTV的均匀指数(HI)分别为1.052±0.019、1.063±0.016、1.075±0.020,VMAT计划分别为1.037±0.008、1.047 ±0.008、1.072±0.018,差异均无统计学意义.5F-IMRT和 VMAT计划中重耍的危及器官如小肠、膀胱和股骨头等的关键剂量评价指标(D5、Dmin、Dmean和Dmax)差异均无统计学意义(P>0.05).小肠、膀胱和股骨头等受照射体积的关键评价指标(V20、V30、V40和V50)在两种放疗计划中差异均无统计学意义(P>0.05).结论 5F-IMRT和VMAT计划靶区的剂量分布均较理想,对小肠、膀胱、双侧股骨头等正常组织均有很好的保护作用.%Objective To investigate the dosimetric comparison between prenperalive live-field intensity modulated radiotherapy (5F-IMRT) and volumetric modulated arc therapy ( VMAT) in the. rectum cancer patients with concurrent chemotherapy and radiotherapy. Methods With the application of CMS monaco syslems( V2. 0,Sweden) , 5F-IMRT and VMAT plans were simulated in 23 rectum cancer patients with preoperative concurrent chemoradlotherapy. The dose characteristic of target volume was evaluated and the dose-volume relationship of small bowel, bladder and bilateral femoral head was compared. Results The CI was similar between the 5F-IMRT(0. 810 ±0. 043) and VMAT plans(0. 822 ±0. 062) , which could satisfy 95% of prescribed dose for covered PTV. The HI of the prescribed dose to GTV( 1. 052 ±0. 019 vs. 1

  5. Dosimetric effects of setup uncertainties on breast treatment delivery.

    Science.gov (United States)

    Harron, Elizabeth Christine; McCallum, Hazel Mhairi; Lambert, Elizabeth Lyn; Lee, Daniela; Lambert, Geoffrey David

    2008-01-01

    This study aimed to assess the dosimetric impact of setup errors during the delivery of radiotherapy to the breast, and use this information to make recommendations on intervention tolerances for portal imaging of breast treatments. Translational and rotational setup errors were simulated for 10 recent breast patients using an Oncentra MasterPlan treatment planning system. The effect of these errors on the breast and tumor bed target volumes receiving 95% and 107% of the prescribed dose were assessed. For the majority of patients, shifts of up to 10 mm or a 4 degrees patient rotation about the cranio-caudal axis had no significant effect on the dose distribution. Changes in dosimetry were more likely if the reference plan contained large hot or cold spots. For a typical patient, it is estimated that a shift of 5 mm in any one direction, or a 2 degrees patient rotation would not cause more than a 5% change in the target volume receiving between 95% and 107% of the prescribed dose. If combinations of errors occur, greater dosimetric changes would be expected. It is concluded that individual patient shifts of up to 5 mm or rotations about the cranio-caudal axis of 2 degrees or less are unlikely to affect dose-volume histogram parameters by an amount judged as clinically significant. Setup errors exceeding these values may cause large dosimetric changes for some patients, particularly those with larger hot or cold regions in the dose distribution, and intervention is therefore recommended.

  6. Effective atomic numbers and electron density of dosimetric material

    Directory of Open Access Journals (Sweden)

    Kaginelli S

    2009-01-01

    Full Text Available A novel method for determination of mass attenuation coefficient of x-rays employing NaI (Tl detector system and radioactive sources is described.in this paper. A rigid geometry arrangement and gating of the spectrometer at FWHM position and selection of absorber foils are all done following detailed investigation, to minimize the effect of small angle scattering and multiple scattering on the mass attenuation coefficient, m/r, value. Firstly, for standardization purposes the mass attenuation coefficients of elemental foils such as Aluminum, Copper, Molybdenum, Tantalum and Lead are measured and then, this method is utilized for dosimetric interested material (sulfates. The experimental mass attenuation coefficient values are compared with the theoretical values to find good agreement between the theory and experiment within one to two per cent. The effective atomic numbers of the biological substitute material are calculated by sum rule and from the graph. The electron density of dosimetric material is calculated using the effective atomic number. The study has discussed in detail the attenuation coefficient, effective atomic number and electron density of dosimetric material/biological substitutes.

  7. Cytogenetic and dosimetric effects of {sup 131}I in lymphocyte of patients with differentiated thyroid cancer with and without r-hTSH stimulation. Study in thyroid tumor cells (WRO) treated with {sup 131}I and {sup 60}Co in vitro; Efeitos citogenetico e dosimetrico do {sup 131}I em pacientes com cancer diferenciado da tireoide com e sem estimulacao com r-hTSH. Estudo em celulas tumorais tireoidianas (WRO) tratadas com {sup 131}I e {sup 60}Co in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Valgode, Flavia Gomes Silva

    2015-11-01

    Differentiated thyroid cancer (DTC) represents about 90% of thyroid malignancies with increasing incidence in the recent decades. Treatment modalities include thyroidectomy, {sup 131}I therapy (with or without r-hTSH), radio and chemotherapy. Little is known about the effects of these treatments at the cellular level. This work was proposed in order to assess to what extent radioiodine therapy can cause damage in peripheral lymphocytes of patients with DTC, preceded or not by r-hTSH, taking into account acute, slow and dosimetric effects of {sup 131}I (in vivo study). An in vitro study was also carried out on thyroid tumor target cells (WRO) by cytotoxicity and genotoxicity analysis and radioiodine uptake. For this, blood samples from patients divided into two groups (group A, r-hTSH + {sup 131}I and group B,{sup 131}I only) were collected before, 24 hours, 1 week, 1 month and 1 year after {sup 131}I administration for aberration chromosome analysis (CA). A dose-response curve for {sup 131}I in vitro was developed for estimating the absorbed dose in patients, comparing the dicentric frequencies obtained in vitro with in vivo data by Monte Carlo program. Radioiodine therapy induced an increase in the number of CA in lymphocytes of patients peaking 24 hours after treatment, with gradual decline over time and with more chromosomal damage in group B than in group A, reaching baseline levels one year after radioiodine administration. The frequency of dicentric found inpatient lymphocytes, 24h after treatment, was equivalent to that induced in vitro (0.354 ± 0.153 MBq / mL for group A and 0.309 ± 0.154 MBq / mL for group B), which corresponds to absorbed doses of 0.8 ± 0.3 Gy and 0.7 ± 0.3 Gy for groups A and B, respectively, with no significant difference between the groups. WRO cells showed a cell cycle relatively slow: 96,3h with an unstable karyotype. The genotoxic test showed a relatively high radioresistance (0.07 to 3.70 MBq/mL), with no statistical

  8. Dosimetric comparison between techniques for irradiation of breast plastron;Comparacao dosimetrica entre tecnicas de irradiacao de plastrao mamario

    Energy Technology Data Exchange (ETDEWEB)

    Trinca, W.C.; Bruning, F.F.; Caldeira, F A.M.; Silveira, T.B da; Batista, D.V.S. [Instituto Nacional de Cancer (INCA), Rio de Janeiro, RJ (Brazil). Area de Fisica Medica; Andrade, R.R. [Instituto Nacional de Cancer (INCA), Rio de Janeiro, RJ (Brazil). Servico de Radioterapia

    2009-07-01

    Patients with breast cancer undergoing radical mastectomy has as an indication of adjuvancy the irradiation of the breast plastron. This paper makes a comparison between different techniques for treatment of breast plastron routinely used in the National Cancer Institute of Brazil (INCA): The irradiation with tangential fields of photons at 6 MV linear accelerator and irradiation with direct angled fields of electron beams of 6 and 9 MeV. We performed dosimetric comparisons in a tissue-equivalent phantom with the use of radiochromic films for verification of coverage and homogeneity of dose for all technical requirements. Tangential fields in the coverage and homogeneity were satisfactory and well cover the clinical aspects as well as beam 9 MeV, despite a small loss at the edge of the external field. Already in 6 MeV beam, there was significant loss in the end, with significant subdoses of 3 cm in the last field. (author)

  9. Dosimetric comparison of intensity modulated radiosurgery with dynamic conformal arc radiosurgery for small cranial lesions

    Directory of Open Access Journals (Sweden)

    Juan F Calvo-Ortega

    2016-01-01

    Conclusions: We have shown that IMRS provides the dosimetric advantages compared with DCARS. Based on the dosimetric findings in this study, fixed gantry IMRS technique can be adopted as a standard procedure for cranial SRS when micro-MLC technology is not available on the linear accelerator.

  10. Multi-catheter interstitial brachytherapy for partial breast irradiation: an audit of implant quality based on dosimetric evaluation comparing intra-operative versus post-operative placement

    Science.gov (United States)

    Gurram, Lavanya; Joshi, Kishor; Phurailatpam, Reena; Paul, Siji; Sarin, Rajiv

    2016-01-01

    Purpose The use of multicatheter interstitial brachytherapy (MIB) for accelerated partial breast irradiation (APBI) in early breast cancer (EBC) patients outside the trial setting has increased. Hence, there is a need to critically evaluate implant quality. Moreover, there is a scarcity of reports using an open cavity technique. We report the dosimetric indices of open and closed cavity MIB techniques. Material and methods The dosimetric parameters of 60 EBC patients treated with MIB (open and closed cavity) who underwent three dimensional, computerized tomography (CT) based planning for APBI from November 2011 to July 2015 were evaluated. Coverage Index (CI), Dose Homogeneity Index (DHI), Conformity Index (COIN), Plan Quality Index (PQI), and Dose Non-uniformity Index (DNR) were assessed. Results Forty-one patients underwent open cavity and 19 patients underwent closed cavity placement of brachytherapy catheters. The median number of planes was 4 and median number of needles was 20. Median dose was 34 Gy with dose per fraction of 3.4 Gy, given twice a day, 6 hours apart. The D90 of the cavity and clinical target volume (CTV) were 105% and 89%, respectively. The median doses to the surgical clips were greater than 100%. The median CI of the cavity and CTV was 0.96 and 0.82, respectively. The DHI and COIN index of the CTV was 0.73 and 0.67. There were no significant differences in the dosimetric parameters based on whether the technique was done open or closed. Conclusions Critical evaluation of the dosimetric parameters of MIB-APBI is important for optimal results. While the open and closed techniques have similar dosimetry, our institutional preference is for an open technique which eases the procedure due to direct visualization of the tumor cavity. PMID:27257415

  11. Study of the thermoluminescence dosimetric properties of window glass

    Science.gov (United States)

    Engin, Birol; Aydaş, Canan; Demirtaş, Hayrünnisa

    2010-01-01

    This paper presents the main thermoluminescence (TL) dosimetric characteristics of commercial Turkish transparent window glass. The structure of the glow curves, including the number of peaks, was found to be dose-dependent. A low-temperature glow peak that at 160 °C shifts to higher temperatures was also observed with increasing storage time at room temperature. This result suggests that this TL glow peak is actually made up of two or more overlapping peaks. These we have attributed to the glow peaks at lower temperatures, which decay faster than the ones at higher temperatures with storage time. The thermal fading of the window glass sample at room temperature showed a relatively sharp decay of about 60% occurring over a period of 28 days, after which the decay rate is small for a measured period of 250 days. In order to the improve the post-irradiation stability of the glow curve, the glass samples were heated after irradiation. To remove the unstable TL peaks responsible for the initial rapid fading, post-irradiation heating at 160 °C for 10 min was found to be the most suitable procedure. The dosimetric characteristics of the post-irradiation heated window glass examined in this study include fading, gamma photon dose-response, reproducibility, batch sensitivity, humidity influence, a dose-rate effect and photon energy response. Dose-response was found to be appropriate for dosimetry in the range 5 Gy to 10 kGy. The post-irradiation heating procedure did not affect the main dosimetric characteristics of the window glass samples. The results in this work suggest that the materials could, by using the TL technique, be a suitable candidate for alternative dose measurements in radiation processing, provided that a judicious choice of the post-irradiation heat temperature is made to minimize fading.

  12. CURRENT STATUS OF INDIVIDUAL DOSIMETRIC MONITORING IN UKRAINE.

    Science.gov (United States)

    Chumak, V; Deniachenko, N; Makarovska, O; Mihailescu, L-C; Prykhodko, A; Voloskyi, V; Vanhavere, F

    2016-09-01

    About 50 000 workers are being occupationally exposed to radiation in Ukraine. Individual dosimetric monitoring (IDM) is provided by 77 dosimetry services and laboratories of very different scale with a number of monitored workers ranging from several persons to ∼9000. In the present work, the current status of personal dosimetry in Ukraine was studied. The First National Intercomparison (FNI) of the IDM labs was accompanied by a survey of the laboratory operation in terms of coverage, types of dosimetry provided, instrumentation and methodologies used, metrological support, data recording, etc. Totally, 34 laboratories responded to the FNI call, and 18 services with 19 different personal dosimetry systems took part in the intercomparison exercise providing 24 dosimeters each for blind irradiation to photons of 6 different qualities (ISO N-series X-rays, S-Cs and S-Co sources) in a dose range of 5-60 mSv. Performance of the dosimetry labs was evaluated according to ISO 14146 criteria of matching trumpet curves with H0 = 0.2 mSv. The test revealed that 8 of the 19 systems meet ISO 14146 criteria in full, 5 other labs show marginal performance and 6 laboratories demonstrated catastrophic quality of dosimetric results. Altogether, 18 participating labs provide dosimetric monitoring to 37 477 workers (about three-fourths of all occupationally exposed workers), usually on monthly (nuclear industry) or quarterly (rest of applications) basis. Of this number, 20 664 persons (55 %) receive completely adequate individual monitoring, and the number of personnel receiving IDM of inadequate quality counts 3054 persons.

  13. Effect of endorectal balloon positioning errors on target deformation and dosimetric quality during prostate SBRT

    Science.gov (United States)

    Jones, Bernard L.; Gan, Gregory; Kavanagh, Brian; Miften, Moyed

    2013-11-01

    An inflatable endorectal balloon (ERB) is often used during stereotactic body radiation therapy (SBRT) for treatment of prostate cancer in order to reduce both intrafraction motion of the target and risk of rectal toxicity. However, the ERB can exert significant force on the prostate, and this work assessed the impact of ERB position errors on deformation of the prostate and treatment dose metrics. Seventy-one cone-beam computed tomography (CBCT) image datasets of nine patients with clinical stage T1cN0M0 prostate cancer were studied. An ERB (Flexi-Cuff, EZ-EM, Westbury, NY) inflated with 60 cm3 of air was used during simulation and treatment, and daily kilovoltage (kV) CBCT imaging was performed to localize the prostate. The shape of the ERB in each CBCT was analyzed to determine errors in position, size, and shape. A deformable registration algorithm was used to track the dose received by (and deformation of) the prostate, and dosimetric values such as D95, PTV coverage, and Dice coefficient for the prostate were calculated. The average balloon position error was 0.5 cm in the inferior direction, with errors ranging from 2 cm inferiorly to 1 cm superiorly. The prostate was deformed primarily in the AP direction, and tilted primarily in the anterior-posterior/superior-inferior plane. A significant correlation was seen between errors in depth of ERB insertion (DOI) and mean voxel-wise deformation, prostate tilt, Dice coefficient, and planning-to-treatment prostate inter-surface distance (p < 0.001). Dosimetrically, DOI is negatively correlated with prostate D95 and PTV coverage (p < 0.001). For the model of ERB studied, error in ERB position can cause deformations in the prostate that negatively affect treatment, and this additional aspect of setup error should be considered when ERBs are used for prostate SBRT. Before treatment, the ERB position should be verified, and the ERB should be adjusted if the error is observed to exceed tolerable values.

  14. Biokinetic and dosimetric studies of {sup 188}Re-hyaluronic acid: a new radiopharmaceutical for treatment of hepatocellular carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Melendez-Alafort, Laura [Dipartimento di Scienze Farmaceutiche, Universita degli Studi di Padova, 35131 Padua (Italy)], E-mail: laura.melendez@unipd.it; Nadali, Anna; Zangoni, Elena [Dipartimento di Scienze Farmaceutiche, Universita degli Studi di Padova, 35131 Padua (Italy); Banzato, Alessandra; Rondina, Maria [Dipartimento di Scienze Oncologiche e Chirurgiche, Universita degli Studi di Padova, Padua (Italy); Rosato, Antonio [Dipartimento di Scienze Oncologiche e Chirurgiche, Universita degli Studi di Padova, Padua (Italy); Istituto Oncologico Veneto, IOV, Padova, Padua (Italy); Mazzi, Ulderico [Dipartimento di Scienze Farmaceutiche, Universita degli Studi di Padova, 35131 Padua (Italy)

    2009-08-15

    Hepatocellular carcinoma (HCC) is the most common primary liver cancer and has very limited therapeutic options. Recently, it has been found that hyaluronic acid (HA) shows selective binding to CD44 receptors expressed in most cancer histotypes. Since the trend in cancer treatment is the use of targeted radionuclide therapy, the aim of this research was to label HA with rhenium-188 and to evaluate its potential use as a hepatocarcinoma therapeutic radiopharmaceutical. Methods: {sup 188}Re-HA was prepared by a direct labelling method to produce a ReO(O-COO){sub 2}-type coordination complex. {sup 188}Re-HA protein binding and its stability in saline, phosphate buffer, human serum and cysteine solutions were determined. Biokinetic and dosimetric data were estimated in healthy mice (n=60) using the Medical Internal Radiation Dose methodology and mouse model beta-absorbed fractions. To evaluate liver toxicity, alanine aminotranferase (AST) and aspartate aminotranferase (ALT) levels in mice were assessed and the liver maximum tolerated dose (MTD) of {sup 188}Re-HA was determined. Results: A stable complex of {sup 188}Re-HA was obtained with high radiochemical purity (>90%) and low serum protein binding (2%). Biokinetic studies showed a rapid blood clearance (T{sub 1/2}{alpha}=21 min). Four hours after administration, {sup 188}Re-HA was almost totally removed from the blood by the liver due to the selective uptake via HA-specific receptors (73.47{+-}5.11% of the injected dose). The liver MTD in mice was {approx}40 Gy after 7.4 MBq of {sup 188}Re-HA injection. Conclusions: {sup 188}Re-HA complex showed good stability, pharmacokinetic and dosimetric characteristics that confirm its potential as a new agent for HCC radiation therapy.

  15. Dosimetric comparison of helical tomo-therapy and standard three-dimensional conformations radiotherapy within the frame of the treatment of a left breast cancer; Comparaison dosimetrique d'une tomotherapie helicoidale et d'une radiotherapie standard conformationnelle tridimensionnelle dans le cadre du traitement du cancer du sein gauche

    Energy Technology Data Exchange (ETDEWEB)

    Abrous-Anane, S.; Dessard-Diana, B.; Durdux, C.; Giraud, P.; Housset, M.; Giraud, P. [Hopital europeen Georges-Pompidou, 75 - Paris (France); Yassa, M. [Hopital Maisonneuve-Rosemont, Montreal (Canada); Hijal, T. [McGill University Health Centre, Montreal (Canada)

    2010-10-15

    The use of intensity-modulated conformational radiotherapy (IMRT) resulted in a reduction of early side effects for patients treated by total mammary irradiation. Helical tomo-therapy uses a great number of circumferential beams which are modulated by an ultra-fast multi-blade collimator to deliver an IMRT with a high dose gradient. However, the use of this technique has been limited for the treatment of breast cancer because of the increased treatment duration and of the increase of low doses for organs at risk. The authors describe a simple technique to irradiate in a conformational and homogeneous way the whole mammary target volume while reducing the dose delivered to organs at risk. They discuss the results obtained during eight treatments of patients suffering from a left breast cancer. Short communication

  16. Validation of the adjusted strength criterion LaRC04 for uni-directional composite under combination of tension and pressure

    Directory of Open Access Journals (Sweden)

    Krystek J.

    2010-12-01

    Full Text Available Strength of unidirectional composite materials for some combinations of state of stress cannot be successsfully predicted even with modern failure criteria. In case of the combination of compression in the transverse direction and tension in the fiber direction, the criterion LaRC04 was adjusted in previous work. The predicted strengths in this case reach significantly larger values compared to the ultimate strengths of the material in the respective directions. The adjusted criterion is able to predict the failure of unidirectional composite in case of the mentioned combination of loading. The validation of the adjusted criterion is carried out by means of the comparison of experimental results and numerical analysis performed in finite element system MSC.Marc.

  17. Biokinetic and dosimetric modelling in the estimation of radiation risks from internal emitters.

    Science.gov (United States)

    Harrison, John

    2009-06-01

    The International Commission on Radiological Protection (ICRP) has developed biokinetic and dosimetric models that enable the calculation of organ and tissue doses for a wide range of radionuclides. These are used to calculate equivalent and effective dose coefficients (dose in Sv Bq(-1) intake), considering occupational and environmental exposures. Dose coefficients have also been given for a range of radiopharmaceuticals used in diagnostic medicine. Using equivalent and effective dose, exposures from external sources and from different radionuclides can be summed for comparison with dose limits, constraints and reference levels that relate to risks from whole-body radiation exposure. Risk estimates are derived largely from follow-up studies of the survivors of the atomic bombings at Hiroshima and Nagasaki in 1945. New dose coefficients will be required following the publication in 2007 of new ICRP recommendations. ICRP biokinetic and dosimetric models are subject to continuing review and improvement, although it is arguable that the degree of sophistication of some of the most recent models is greater than required for the calculation of effective dose to a reference person for the purposes of regulatory control. However, the models are also used in the calculation of best estimates of doses and risks to individuals, in epidemiological studies and to determine probability of cancer causation. Models are then adjusted to best fit the characteristics of the individuals and population under consideration. For example, doses resulting from massive discharges of strontium-90 and other radionuclides to the Techa River from the Russian Mayak plutonium plant in the early years of its operation are being estimated using models adapted to take account of measurements on local residents and other population-specific data. Best estimates of doses to haemopoietic bone marrow, in utero and postnatally, are being used in epidemiological studies of radiation-induced leukaemia

  18. Locally advanced rectal cancer: management challenges

    Directory of Open Access Journals (Sweden)

    Kokelaar RF

    2016-10-01

    Full Text Available RF Kokelaar, MD Evans, M Davies, DA Harris, J Beynon Department of Colorectal Surgery, Singleton Hospital, Swansea, UK Abstract: Between 5% and 10% of patients with rectal cancer present with locally advanced rectal cancer (LARC, and 10% of rectal cancers recur after surgery, of which half are limited to locoregional disease only (locally recurrent rectal cancer. Exenterative surgery offers the best long-term outcomes for patients with LARC and locally recurrent rectal cancer so long as a complete (R0 resection is achieved. Accurate preoperative multimodal staging is crucial in assessing the potential operability of advanced rectal tumors, and resectability may be enhanced with neoadjuvant therapies. Unfortunately, surgical options are limited when the tumor involves the lateral pelvic sidewall or high sacrum due to the technical challenges of achieving histological clearance, and must be balanced against the high morbidity associated with resection of the bony pelvis and significant lymphovascular structures. This group of patients is usually treated palliatively and subsequently survival is poor, which has led surgeons to seek innovative new solutions, as well as revisit previously discarded radical approaches. A small number of centers are pioneering new techniques for resection of beyond-total mesorectal excision tumors, including en bloc resections of the sciatic notch and composite resections of the first two sacral vertebrae. Despite limited experience, these new techniques offer the potential for radical treatment of previously inoperable tumors. This narrative review sets out the challenges facing the management of LARCs and discusses evolving management options. Keywords: rectal cancer, exenteration, pelvic sidewall, sacrectomy

  19. Dosimetric characteristics of the Siemens IGRT carbon fiber tabletop.

    Science.gov (United States)

    Spezi, Emiliano; Ferri, Andrea

    2007-01-01

    In this work, the dosimetric characteristics of a new commercial carbon fiber treatment table are investigated. The photon beam attenuation properties of the Siemens image-guided radiation therapy (IGRT) tabletop were studied in detail. Two sets of dosimetric measurements were performed. In the first experiment a polystyrene slab phantom was used: the central axis attenuation and the skin-sparing detriment were investigated. In the second experiment, the off-axis treatment table transmission was investigated using a polystyrene cylindrical phantom. Measurements were taken at the isocenter for a 360 degrees rotation of the radiation beam. Our results show that the photon beam attenuation of the Siemens IGRT carbon fiber tabletop varies from a minimum of 2.1% (central axis) to a maximum of 4.6% (120 degrees and 240 degrees beam incidence). The beam entrance dose increases from 82% to 97% of the dose at the depth of maximum for a clinical 6-MV radiation field. The depth of maximum also decreases by 0.4 cm. Despite the wedge cross section of the table the beam attenuation properties of the IGRT tabletop remain constant along the longitudinal direction. American Association of Medical Dosimetrists.

  20. A critical review of {sup 55}Fe dosimetric models

    Energy Technology Data Exchange (ETDEWEB)

    Thind, K.S. [Ontario Hydro Nuclear, Whitby, Ontario (Canada)

    1995-01-01

    The available literature on {sup 55}Fe dosimetry has been devoted to environmental exposures and medical iron kinetic studies. For occupational dosimetry, ICRP published a non-recycling dosimetric model for iron. These ICRP publications do not provide information on iron excretion. Johnson and Dunford published dose conversion factors and urinary excretion curves based on the ICRP and MIRD iron metabolic models. A critical review of these models was undertaken to select a model for occupational dose assignment. The review indicated that the information and recommendations in ICRP and Johnson and Dunford are dependent on unrealistic assumptions that do not agree with known iron metabolism. Therefore, an alternative model is proposed for dosimetric application. Calculations of dose conversion factors and urinary excretion curve for class W{sup 55}Fe inhalation exposure (1 {mu}m AMAD) using the proposed model are compared with predictions based on ICRP and Johnson and Dunford models. The difference in the practical outcome (i.e., dose assignment) is examined by applying the proposed and reviewed models to a realistic bioassay case. The Johnson and Dunford model yields a dose estimate which is roughly a factor of ten higher than values predicted by ICRP and the proposed model. Some of the disagreement is due to uncertainty in the fraction of radio-iron excretion via urine. Further research on this subject is recommended. In the interim, the proposed model is recommended for occupational dose assignment. 31 refs., 6 figs., 9 tabs.

  1. Dosimetric algorithm to reproduce isodose curves obtained from a LINAC.

    Science.gov (United States)

    Estrada Espinosa, Julio Cesar; Martínez Ovalle, Segundo Agustín; Pereira Benavides, Cinthia Kotzian

    2014-01-01

    In this work isodose curves are obtained by the use of a new dosimetric algorithm using numerical data from percentage depth dose (PDD) and the maximum absorbed dose profile, calculated by Monte Carlo in a 18 MV LINAC. The software allows reproducing the absorbed dose percentage in the whole irradiated volume quickly and with a good approximation. To validate results an 18 MV LINAC with a whole geometry and a water phantom were constructed. On this construction, the distinct simulations were processed by the MCNPX code and then obtained the PDD and profiles for the whole depths of the radiation beam. The results data were used by the code to produce the dose percentages in any point of the irradiated volume. The absorbed dose for any voxel's size was also reproduced at any point of the irradiated volume, even when the voxels are considered to be of a pixel's size. The dosimetric algorithm is able to reproduce the absorbed dose induced by a radiation beam over a water phantom, considering PDD and profiles, whose maximum percent value is in the build-up region. Calculation time for the algorithm is only a few seconds, compared with the days taken when it is carried out by Monte Carlo.

  2. Dosimetric Algorithm to Reproduce Isodose Curves Obtained from a LINAC

    Directory of Open Access Journals (Sweden)

    Julio Cesar Estrada Espinosa

    2014-01-01

    Full Text Available In this work isodose curves are obtained by the use of a new dosimetric algorithm using numerical data from percentage depth dose (PDD and the maximum absorbed dose profile, calculated by Monte Carlo in a 18 MV LINAC. The software allows reproducing the absorbed dose percentage in the whole irradiated volume quickly and with a good approximation. To validate results an 18 MV LINAC with a whole geometry and a water phantom were constructed. On this construction, the distinct simulations were processed by the MCNPX code and then obtained the PDD and profiles for the whole depths of the radiation beam. The results data were used by the code to produce the dose percentages in any point of the irradiated volume. The absorbed dose for any voxel’s size was also reproduced at any point of the irradiated volume, even when the voxels are considered to be of a pixel’s size. The dosimetric algorithm is able to reproduce the absorbed dose induced by a radiation beam over a water phantom, considering PDD and profiles, whose maximum percent value is in the build-up region. Calculation time for the algorithm is only a few seconds, compared with the days taken when it is carried out by Monte Carlo.

  3. Determination of dosimetric quantities in pediatric abdominal computed tomography scans*

    Science.gov (United States)

    Jornada, Tiago da Silva; da Silva, Teógenes Augusto

    2014-01-01

    Objective Aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods The study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results No significant difference was observed in the values for weighted air kerma index (CW), but the differences were relevant in values for volumetric air kerma index (CVOL), air kerma-length product (PKL,CT) and effective dose. Conclusion Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, PKL,CT and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. PMID:25741103

  4. Comprehensive Australasian multicentre dosimetric intercomparison: issues, logistics and recommendations.

    Science.gov (United States)

    Ebert, M A; Harrison, K M; Cornes, D; Howlett, S J; Joseph, D J; Kron, T; Hamilton, C S; Denham, J W

    2009-02-01

    The present paper describes the logistics of the 2004-2008 Australasian Level III Dosimetry Intercomparison. Dosimetric intercomparisons (or 'audits') can be used in radiotherapy to evaluate the accuracy and quality of radiation delivery. An intercomparison was undertaken in New Zealand and Australia to evaluate the feasibility and logistics of ongoing dosimetric intercomparisons that evaluate all steps in the radiotherapy treatment process, known as a 'Level III' intercomparison. The study commenced in 2002 with the establishment of a study team, definition of the study protocol, acquisition of appropriate equipment and recruitment of participating radiotherapy centres. Measurements were undertaken between October 2004 and March 2008, and included collation of data on time, costs and logistics of the study. Forty independent Australian and New Zealand radiotherapy centres agreed to participate. Measurement visits were made to 37 of these centres. Data is presented on the costs of the study and the level of support required. The study involved the participation of 16 staff at the study centre who invested over 4000 hours in the study, and of over 200 professionals at participating centres. Recommendations are provided for future phantom-based intercomparisons. It is hoped that the present paper will be of benefit to any centres or groups contemplating similar activities by identifying the processes involved in establishing the study, the potential hazards and pitfalls, and expected resource requirements.

  5. Determination of dosimetric quantities in pediatric abdominal computed tomography scans

    Energy Technology Data Exchange (ETDEWEB)

    Jornada, Tiago da Silva [Universidade Federal de Sao Paulo (UNIFESP), Sao Paulo, SP (Brazil). Escola Paulista de Medicina. Dept. de Diagnostipo por Imagem; Silva, Teogenes Augusto da, E-mail: silvata@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2014-09-15

    Objective: aiming at contributing to the knowledge on doses in computed tomography (CT), this study has the objective of determining dosimetric quantities associated with pediatric abdominal CT scans, comparing the data with diagnostic reference levels (DRL). Materials and methods: the study was developed with a Toshiba Asteion single-slice CT scanner and a GE BrightSpeed multi-slice CT unit in two hospitals. Measurements were performed with a pencil-type ionization chamber and a 16 cm-diameter polymethylmethacrylate trunk phantom. Results: No significant difference was observed in the values for weighted air kerma index (C{sub W}), but the differences were relevant in values for volumetric air kerma index (C{sub VOL}), air kerma-length product (P{sub KL,CT}) and effective dose. Conclusion: Only the CW values were lower than the DRL, suggesting that dose optimization might not be necessary. However, P{sub KL,CT} and effective dose values stressed that there still is room for reducing pediatric radiation doses. The present study emphasizes the importance of determining all dosimetric quantities associated with CT scans. (author)

  6. Dosimetric Algorithm to Reproduce Isodose Curves Obtained from a LINAC

    Science.gov (United States)

    Estrada Espinosa, Julio Cesar; Martínez Ovalle, Segundo Agustín; Pereira Benavides, Cinthia Kotzian

    2014-01-01

    In this work isodose curves are obtained by the use of a new dosimetric algorithm using numerical data from percentage depth dose (PDD) and the maximum absorbed dose profile, calculated by Monte Carlo in a 18 MV LINAC. The software allows reproducing the absorbed dose percentage in the whole irradiated volume quickly and with a good approximation. To validate results an 18 MV LINAC with a whole geometry and a water phantom were constructed. On this construction, the distinct simulations were processed by the MCNPX code and then obtained the PDD and profiles for the whole depths of the radiation beam. The results data were used by the code to produce the dose percentages in any point of the irradiated volume. The absorbed dose for any voxel's size was also reproduced at any point of the irradiated volume, even when the voxels are considered to be of a pixel's size. The dosimetric algorithm is able to reproduce the absorbed dose induced by a radiation beam over a water phantom, considering PDD and profiles, whose maximum percent value is in the build-up region. Calculation time for the algorithm is only a few seconds, compared with the days taken when it is carried out by Monte Carlo. PMID:25045398

  7. Biologic data, models, and dosimetric methods for internal emitters

    Energy Technology Data Exchange (ETDEWEB)

    Weber, D.A.

    1990-01-01

    The absorbed radiation dose from internal emitters has been and will remain a pivotal factor in assessing risk and therapeutic utility in selecting radiopharmaceuticals for diagnosis and treatment. Although direct measurements of absorbed dose and dose distributions in vivo have been and will continue to be made in limited situations, the measurement of the biodistribution and clearance of radiopharmaceuticals in human subjects and the use of this data is likely to remain the primary means to approach the calculation and estimation of absorbed dose from internal emitters over the next decade. Since several approximations are used in these schema to calculate dose, attention must be given to inspecting and improving the application of this dosimetric method as better techniques are developed to assay body activity and as more experience is gained in applying these schema to calculating absorbed dose. Discussion of the need for considering small scale dosimetry to calculate absorbed dose at the cellular level will be presented in this paper. Other topics include dose estimates for internal emitters, biologic data mathematical models and dosimetric methods employed. 44 refs.

  8. Dosimetric comparison between conventional and conformal radiotherapy for carcinoma cervix: Are we treating the right volumes?

    Directory of Open Access Journals (Sweden)

    Jyotirup Goswami

    2013-01-01

    Full Text Available Background and Purpose: Conventional portals, based on bony anatomy, for external beam radiotherapy for cervical cancer have been repeatedly demonstrated as inadequate. Conversely, with image-based conformal radiotherapy, better target coverage may be offset by the greater toxicities and poorer compliance associated with treating larger volumes. This study was meant to dosimetrically compare conformal and conventional radiotherapy. Materials and Methods: Five patients of carcinoma cervix underwent planning CT scan with IV contrast and targets, and organs at risk (OAR were contoured. Two sets of plans-conventional and conformal were generated for each patient. Field sizes were recorded, and dose volume histograms of both sets of plans were generated and compared on the basis of target coverage and OAR sparing. Results: Target coverage was significantly improved with conformal plans though field sizes required were significantly larger. On the other hand, dose homogeneity was not significantly improved. Doses to the OARs (rectum, urinary bladder, and small bowel were not significantly different across the 2 arms. Conclusion: Three-dimensional conformal radiotherapy gives significantly better target coverage, which may translate into better local control and survival. On the other hand, it also requires significantly larger field sizes though doses to the OARs are not significantly increased.

  9. Dosimetric and Biologic Differences in Flattened and Flattening-Filter-Free Beam Treatment Plans

    CERN Document Server

    Yan, Yue; Bassetti, Michael; Du, Kaifang; Saenz, Daniel; Harari, Paul; Paliwal, Bhudatt R

    2015-01-01

    Purpose: To quantitatively compare the dosimetric and biologic differences in treatment plans from flattened and flattening-filter-free (FFF) beam for three anatomic cancer sites. Methods and Materials: Treatment plans with static intensity-modulated radiotherapy beams and volumetric modulated arc therapy beams were generated for 13 patients for both the flattened beam and the FFF beam of the TrueBeam system. Beam energies of 6 MV and 10 MV were chosen for planning. A total of 104 treatment plans were generated in 13 patients. In order to analyze the biological effectiveness of treatment plans, dose volume histograms (DVH) were utilized. Flattened and FFF beam plans are quantitatively compared. Results: In head and neck cases, for VMAT plans, dose reduction in the FFF beam plans compared to the flattened beam in left cochlea, right submandibular gland and right parotid gland reached up to 2.36 Gy, 1.21 Gy and 1.45 Gy, respectively. Similarly, for static IMRT plans, the dose reduction of the FFF beam plans com...

  10. Potential application of metal nanoparticles for dosimetric systems: Concepts and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Guidelli, Eder José, E-mail: ederguidelli@pg.ffclrp.usp.br; Baffa, Oswaldo, E-mail: ederguidelli@pg.ffclrp.usp.br [Departamento de Física, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeirão Preto, SP (Brazil)

    2014-11-07

    Metallic nanoparticles increase the delivered dose and consequently enhance tissue radio sensitization during radiation therapy of cancer. The Dose Enhancement Factor (DEF) corresponds to the ratio between the dose deposited on a tissue containing nanoparticles, and the dose deposited on a tissue without nanoparticles. In this sense, we have used electron spin resonance spectroscopy (ESR) to investigate how silver and gold nanoparticles affect the dose deposition in alanine dosimeters, which act as a surrogate of soft tissue. Besides optimizing radiation absorption by the dosimeter, the optical properties of these metal nanoparticles could also improve light emission from materials employed as radiation detectors. Therefore, we have also examined how the plasmonic properties of noble metal nanoparticles could enhance radiation detection using optically stimulated luminescence (OSL) dosimetry. This work will show results on how the use of gold and silver nanoparticles are beneficial for the ESR and OSL dosimetric techniques, and will describe the difficulties we have been facing, the challenges to overcome, and the perspectives.

  11. Dosimetric evaluation using the diode measurements for total skin electron therapy technique

    Institute of Scientific and Technical Information of China (English)

    Ehab M.Attalla; Nashaat A.Deiab; Walaa S.Abd Elgawad

    2014-01-01

    The purpose of this study was to present the dosimetric study and evaluation the dose delivered to the skin tumor by using diode detector with total skin electron therapy (TSET).Methods: The total skin electron irradiation (TSEI) technique was used to treat ten patients with histological confirmed mycosis fungoides according to the Stanford staging system at the Radiotherapy Department, National Cancer Institute, Cairo University, Egypt. High dose rate electron beams with low electron energy 5 MeV from a Siemens linear accelerator were used for treatment. Diodes were calibrated at TSET distance 300 cm and field size (35 x 35) cm2.Results:The result of diodes measurements showed the dose to flat surface of the body was within ±10 % from the prescribed dose. Special areas of the body such as the perineum & eyelid showed large deviation up to 30% variation from the prescription dose.Conclusion:The diode results of this study wil be used as a quality assurance check for al new patients treated with TSET and to compare it to the prescribed dose delivered to the patients. It is recommends to evaluate the diodes measurements for al patients throughout the ful treatment cycle and to identify individu-aly the boost dose areas.

  12. Dosimetric comparisons of carbon ion treatment plans for 1D and 2D ripple filters with variable thicknesses

    Science.gov (United States)

    Printz Ringbæk, Toke; Weber, Uli; Santiago, Alina; Simeonov, Yuri; Fritz, Peter; Krämer, Michael; Wittig, Andrea; Bassler, Niels; Engenhart-Cabillic, Rita; Zink, Klemens

    2016-06-01

    A ripple filter (RiFi)—also called mini-ridge filter—is a passive energy modulator used in particle beam treatments that broadens the Bragg peak (BP) as a function of its maximum thickness. The number of different energies requested from the accelerator can thus be reduced, which significantly reduces the treatment time. A new second generation RiFi with 2D groove shapes was developed using rapid prototyping, which optimizes the beam-modulating material and enables RiFi thicknesses of up to 6 mm. Carbon ion treatment plans were calculated using the standard 1D 3 mm thick RiFi and the new 4 and 6 mm 2D RiFis for spherical planning target volumes (PTVs) in water, eight stage I non-small cell lung cancer cases, four skull base chordoma cases and three prostate cancer cases. TRiP98 was used for treatment planning with facility-specific base data calculated with the Monte Carlo code SHIELD-HIT12A. Dose-volume-histograms, spatial dose distributions and dosimetric indexes were used for plan evaluation. Plan homogeneity and conformity of thinner RiFis were slightly superior to thicker RiFis but satisfactory results were obtained for all RiFis investigated. For the 6 mm RiFi, fine structures in the dose distribution caused by the larger energy steps were observed at the PTV edges, in particular for superficial and/or very small PTVs but performances for all RiFis increased with penetration depth due to straggling and scattering effects. Plans with the new RiFi design yielded for the studied cases comparable dosimetric results to the standard RiFi while the 4 and 6 mm RiFis lowered the irradiation time by 25-30% and 45-49%, respectively.

  13. Dosimetric comparisons of carbon ion treatment plans for 1D and 2D ripple filters with variable thicknesses.

    Science.gov (United States)

    Ringbæk, Toke Printz; Weber, Uli; Santiago, Alina; Simeonov, Yuri; Fritz, Peter; Krämer, Michael; Wittig, Andrea; Bassler, Niels; Engenhart-Cabillic, Rita; Zink, Klemens

    2016-06-01

    A ripple filter (RiFi)-also called mini-ridge filter-is a passive energy modulator used in particle beam treatments that broadens the Bragg peak (BP) as a function of its maximum thickness. The number of different energies requested from the accelerator can thus be reduced, which significantly reduces the treatment time. A new second generation RiFi with 2D groove shapes was developed using rapid prototyping, which optimizes the beam-modulating material and enables RiFi thicknesses of up to 6 mm. Carbon ion treatment plans were calculated using the standard 1D 3 mm thick RiFi and the new 4 and 6 mm 2D RiFis for spherical planning target volumes (PTVs) in water, eight stage I non-small cell lung cancer cases, four skull base chordoma cases and three prostate cancer cases. TRiP98 was used for treatment planning with facility-specific base data calculated with the Monte Carlo code SHIELD-HIT12A. Dose-volume-histograms, spatial dose distributions and dosimetric indexes were used for plan evaluation. Plan homogeneity and conformity of thinner RiFis were slightly superior to thicker RiFis but satisfactory results were obtained for all RiFis investigated. For the 6 mm RiFi, fine structures in the dose distribution caused by the larger energy steps were observed at the PTV edges, in particular for superficial and/or very small PTVs but performances for all RiFis increased with penetration depth due to straggling and scattering effects. Plans with the new RiFi design yielded for the studied cases comparable dosimetric results to the standard RiFi while the 4 and 6 mm RiFis lowered the irradiation time by 25-30% and 45-49%, respectively.

  14. TG-43 U1 based dosimetric characterization of model 67-6520 Cs-137 brachytherapy source

    Energy Technology Data Exchange (ETDEWEB)

    Meigooni, Ali S.; Wright, Clarissa; Koona, Rafiq A.; Awan, Shahid B.; Granero, Domingo; Perez-Calatayud, Jose; Ballester, Facundo [Department of Radiation Medicine, North Shore University Hospital, 300 Community Drive, Manhasset, New York 11030 and Department of Radiation Medicine, University of Kentucky Chandler Medical Center, Lexington, Kentucky 40536-0084 (United States); Department of Radiation Medicine, University of Kentucky Chandler Medical Center, Lexington, Kentucky 40536-0084 (United States); Department of Radiation Physics, ERESA, Hospital General Universitario, Avenida Tres Cruces, 2, E-46014 Valencia (Spain); Department of Oncology, Physics Section, ' ' La Fe' ' University Hospital, Avenida Campanar 21, E-46009 Valencia (Spain); Department of Atomic, Molecular and Nuclear Physics, University of Valencia, C/ Dr. Moliner 50, E-46100 Burjassot, Spain and Instituto de Fisica Corpuscular (IFIC), C/ Dr. Moliner 50, E-46100 Burjassot (Spain)

    2009-10-15

    Purpose: Brachytherapy treatment has been a cornerstone for management of various cancer sites, particularly for the treatment of gynecological malignancies. In low dose rate brachytherapy treatments, {sup 137}Cs sources have been used for several decades. A new {sup 137}Cs source design has been introduced (model 67-6520, source B3-561) by Isotope Products Laboratories (IPL) for clinical application. The goal of the present work is to implement the TG-43 U1 protocol in the characterization of the aforementioned {sup 137}Cs source. Methods: The dosimetric characteristics of the IPL {sup 137}Cs source are measured using LiF thermoluminescent dosimeters in a Solid Water phantom material and calculated using Monte Carlo simulations with the GEANT4 code in Solid Water and liquid water. The dose rate constant, radial dose function, and two-dimensional anisotropy function of this source model were obtained following the TG-43 U1 recommendations. In addition, the primary and scatter dose separation (PSS) formalism that could be used in convolution/superposition methods to calculate dose distributions around brachytherapy sources in heterogeneous media was studied. Results: The measured and calculated dose rate constants of the IPL {sup 137}Cs source in Solid Water were found to be 0.930({+-}7.3%) and 0.928({+-}2.6%) cGy h{sup -1} U{sup -1}, respectively. The agreement between these two methods was within our experimental uncertainties. The Monte Carlo calculated value in liquid water of the dose rate constant was {Lambda}=0.948({+-}2.6%) cGy h{sup -1} U{sup -1}. Similarly, the agreement between measured and calculated radial dose functions and the anisotropy functions was found to be within {+-}5%. In addition, the tabulated data that are required to characterize the source using the PSS formalism were derived. Conclusions: In this article the complete dosimetry of the newly designed {sup 137}Cs IPL source following the AAPM TG-43 U1 dosimetric protocol and the PSS

  15. Dosimetric properties of natural quartz grains extracted from fired materials

    DEFF Research Database (Denmark)

    Bluszcz, A.; Bøtter-Jensen, L.

    1995-01-01

    The paper describes an examination of the dosimetric properties of natural quartz grains extracted from ancient fired materials. Eleven samples of different origin were tested for their TL and GLSL (green light stimulated luminescence) sensitivities within the mGy dose range. Very promising results...... were obtained showing the possibility of measuring the doses of around 10 mGy with 1% precision using GLSL or TL and using the single aliquot technique for natural quartz as a dosimeter. The lowest detectable dose was estimated to be lower than 500 mu Gy. The results obtained indicate that natural...... quartz grains from selected materials could be used for the dosimetry of environmental gamma radiation for the purposes of paleodosimetric dating methods as well as for accident dosimetry....

  16. Potential ocular damage from microwave exposure during electrosurgery: dosimetric survey

    Energy Technology Data Exchange (ETDEWEB)

    Paz, J.D.; Milliken, R.; Ingram, W.T.; Frank, A.; Atkin, A.

    1987-07-01

    A dosimetric survey of microwave radiation emitted by electrosurgical units used in operating rooms indicated that surgeons expose themselves to levels that may be hazardous, and that ocular exposures are especially high: 20 cm from the active lead, electric field strength at the eye/forehead position was 9.0 X 10(6) V2/M2 for the monopolar unit; and magnetic field strength at this position reached a magnitude of 3.5 A2/M2. These electric and magnetic fields exceeded the TLVs of the American National Standards Institute. The authors concluded that the high levels of microwave radiation generated by electrosurgery devices should receive immediate attention to assess health effects associated with such exposures.

  17. Dosimetrically determined doses of radioiodine for the treatment of metastatic thyroid carcinoma.

    Science.gov (United States)

    Van Nostrand, Douglas; Atkins, Frank; Yeganeh, Fred; Acio, Elmo; Bursaw, Randy; Wartofsky, Leonard

    2002-02-01

    In the absence of definitive studies relating radioiodine dose to outcomes, selection of a dose of radioiodine to treat metastatic thyroid carcinoma is problematic, and several approaches have been used. These include empiric fixed doses and doses used on dosimetric approaches specific for each patient. This paper is a review of the rationale and technique for dosimetrically-determined doses of radioiodine for the treatment of metastatic thyroid carcinoma. This review (1) discusses the alternatives for selection of a dose, (2) discusses the two major approaches for determining radioiodine doses dosimetrically, (3) briefly reviews several modifications of these approaches, (4) reviews the literature regarding the results, (5) discusses the side effects of these different approaches, and (6) concludes with recommendations for patient management and future research. This review does not address use of dosimetrically-determined doses of radioiodine for the initial ablation of thyroid tissue postoperatively.

  18. Dosimetric properties of a scanned beam microtron at low monitor unit settings: importance for conformal therapy.

    Science.gov (United States)

    Humm, J L; Larsson, A; Lief, E P

    1996-03-01

    The dosimetric stability, linearity, dose rate dependence, and flatness of both photon and electron beams have been evaluated for a racetrack microtron at low monitor unit settings. For photons, the variation in dosimetric output about the mean is 3% at 20 cm, even at only 3 MU, in contrast with other scanned beam accelerators. Broad electron beams on the microtron are created by the superposition of the elementary beam pulses either directly from the scan magnets, or after their broadening through a scattering foil. The dosimetric instability both with and without the foil was less than 0.6% for both the 25- and 50-MeV electrons. Dose nonlinearity was microtron exhibits dosimetric properties which fulfill the recommendations of Task Groups 21 and 25. Based on the stability of the scanned beam at low monitor unit settings, the microtron can be used for 3-D conformal therapy with both photons and electrons.

  19. Effect of endorectal balloon positioning errors on target deformation and dosimetric quality during prostate SBRT.

    Science.gov (United States)

    Jones, Bernard L; Gan, Gregory; Kavanagh, Brian; Miften, Moyed

    2013-11-21

    An inflatable endorectal balloon (ERB) is often used during stereotactic body radiation therapy (SBRT) for treatment of prostate cancer in order to reduce both intrafraction motion of the target and risk of rectal toxicity. However, the ERB can exert significant force on the prostate, and this work assessed the impact of ERB position errors on deformation of the prostate and treatment dose metrics. Seventy-one cone-beam computed tomography (CBCT) image datasets of nine patients with clinical stage T1cN0M0 prostate cancer were studied. An ERB (Flexi-Cuff, EZ-EM, Westbury, NY) inflated with 60 cm(3) of air was used during simulation and treatment, and daily kilovoltage (kV) CBCT imaging was performed to localize the prostate. The shape of the ERB in each CBCT was analyzed to determine errors in position, size, and shape. A deformable registration algorithm was used to track the dose received by (and deformation of) the prostate, and dosimetric values such as D95, PTV coverage, and Dice coefficient for the prostate were calculated. The average balloon position error was 0.5 cm in the inferior direction, with errors ranging from 2 cm inferiorly to 1 cm superiorly. The prostate was deformed primarily in the AP direction, and tilted primarily in the anterior-posterior/superior-inferior plane. A significant correlation was seen between errors in depth of ERB insertion (DOI) and mean voxel-wise deformation, prostate tilt, Dice coefficient, and planning-to-treatment prostate inter-surface distance (p prostate D95 and PTV coverage (p prostate that negatively affect treatment, and this additional aspect of setup error should be considered when ERBs are used for prostate SBRT. Before treatment, the ERB position should be verified, and the ERB should be adjusted if the error is observed to exceed tolerable values.

  20. Effect of blood activity on dosimetric calculations for radiopharmaceuticals

    Science.gov (United States)

    Zvereva, Alexandra; Petoussi-Henss, Nina; Li, Wei Bo; Schlattl, Helmut; Oeh, Uwe; Zankl, Maria; Graner, Frank Philipp; Hoeschen, Christoph; Nekolla, Stephan G.; Parodi, Katia; Schwaiger, Markus

    2016-11-01

    dosimetric calculations. Hence, blood samples should be included in all pharmacokinetic and dosimetric studies for new tracers if possible.

  1. Estimating dosimetric quantities of radon progeny using human CT scan data and small tissue volume analysis with Geant4 code system

    Directory of Open Access Journals (Sweden)

    Van Den Akker Evelynn

    2015-01-01

    Full Text Available Estimating the health effects of radon exposure is of great interest because radon is considered the second leading cause of lung cancer after smoking. The dose-response curve is not well understood at low-dose levels where radon exposure is estimated. Therefore, the health mechanisms of radiation due to radon progeny at the cellular and molecular levels are of interest for providing an indication of a possible threshold value above which the exposure may indicate cancer formation. In this paper we present a macroscopic and cellular level numerical analysis of the radon-induced dose estimates based on the Geant4 code system. Macroscopic estimates are assessed based on patient-specific computer tomography scans that provide geometries easily applicable to modeling radiation effects of the radon progeny sources. A small tissue volumes analysis based on the Geant4 code system is developed so as to provide information about the interactions and particle track structures at the microscopic (cellular levels producing the dosimetric effects of radon short-lived progenies. The results presented in this paper also call attention to the capabilities of Geant4 to provide radon-related dosimetric parameters of large and small-scale biological systems.

  2. Peripheral myeloid-derived suppressor and T regulatory PD-1 positive cells predict response to neoadjuvant short-course radiotherapy in rectal cancer patients.

    Science.gov (United States)

    Napolitano, Maria; D'Alterio, Crescenzo; Cardone, Eleonora; Trotta, Anna Maria; Pecori, Biagio; Rega, Daniela; Pace, Ugo; Scala, Dario; Scognamiglio, Giosuè; Tatangelo, Fabiana; Cacciapuoti, Carmela; Pacelli, Roberto; Delrio, Paolo; Scala, Stefania

    2015-04-10

    Short-course preoperative radiotherapy (SC-RT) followed by total mesorectal excision (TME) is one therapeutic option for locally advanced rectal cancer (LARC) patients. Since radio-induced DNA damage may affect tumor immunogenicity, Myeloid-derived suppressor cells (MDSCs) and T regulatory cells (Tregs) were evaluated in 13 patients undergoing SC-RT and TME for LARC. Peripheral Granulocytic-MDSCs (G-MDSC) [LIN-/HLA-DR-/CD11b+/CD14-/CD15+/CD33+], Monocytic (M-MDSC) [CD14+/HLA-DR-/lowCD11b+/CD33+] and Tregs [CD4+/CD25hi+/FOXP3+- CTLA-4/PD1] basal value was significantly higher in LARC patients compared to healthy donors (HD). Peripheral MDSC and Tregs were evaluated at time 0 (T0), after 2 and 5 weeks (T2-T5) from radiotherapy; before surgery (T8) and 6-12 months after surgery (T9, T10). G-MDSC decreased at T5 and further at T8 while M-MDSC cells decreased at T5; Tregs reached the lowest value at T5. LARC poor responder patients displayed a major decrease in M-MDSC after SC-RT and an increase of Treg-PD-1. In this pilot study MDSCs and Tregs decrease during the SC-RT treatment could represent a biomarker of response in LARC patients. Further studies are needed to confirm that the deepest M-MDSC reduction and increase in Treg-PD1 cells within 5-8 weeks from the beginning of treatment could discriminate LARC patients poor responding to SC-RT.

  3. Dosimetric characterization and application of an imaging beam line with a carbon electron target for megavoltage cone beam computed tomography.

    Science.gov (United States)

    Flynn, Ryan T; Hartmann, Julia; Bani-Hashemi, Ali; Nixon, Earl; Alfredo, R; Siochi, C; Pennington, Edward C; Bayouth, John E

    2009-06-01

    Imaging dose from megavoltage cone beam computed tomography (MVCBCT) can be significantly reduced without loss of image quality by using an imaging beam line (IBL), with no flattening filter and a carbon, rather than tungsten, electron target. The IBL produces a greater keV-range x-ray fluence than the treatment beam line (TBL), which results in a more optimal detector response. The IBL imaging dose is not necessarily negligible, however. In this work an IBL was dosimetrically modeled with the Philips Pinnacle3 treatment planning system (TPS), verified experimentally, and applied to clinical cases. The IBL acquisition dose for a 200 degrees gantry rotation was verified in a customized acrylic cylindrical phantom at multiple imaging field sizes with 196 ion chamber measurements. Agreement between the measured and calculated IBL dose was quantified with the 3D gamma index. Representative IBL and TBL imaging dose distributions were calculated for head and neck and prostate patients and included in treatment plans using the imaging dose incorporation (IDI) method. Surface dose was measured for the TBL and IBL for four head and neck cancer patients with MOSFETs. The IBL model, when compared to the percentage depth dose and profile measurements, had 97% passing gamma indices for dosimetric and distance acceptance criteria of 3%, 3 mm, and 100% passed for 5.2%, 5.2 mm. For the ion chamber measurements of phantom image acquisition dose, the IBL model had 93% passing gamma indices for acceptance criteria of 3%, 3 mm, and 100% passed for 4%, 4 mm. Differences between the IBL- and TBL-based IMRT treatment plans created with the IDI method were dosimetrically insignificant for both the prostate and head and neck cases. For IBL and TBL beams with monitor unit values that would result in the delivery of the same dose to the depth of maximum dose under standard calibration conditions, the IBL imaging surface dose was higher than the TBL imaging surface dose by an average of 18

  4. SU-E-T-538: Lung SBRT Dosimetric Comparison of 3D Conformal and RapidArc Planning

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, R; Zhan, L; Osei, E [Grand River Hospital, Kitchener, ON (Canada)

    2015-06-15

    Purpose: Dose distributions of RapidArc Plan can be quite different from standard 3D conformal radiation therapy. SBRT plans can be optimized with high conformity or mimic the 3D conformal treatment planning with very high dose in the center of the tumor. This study quantifies the dosimetric differences among 3D conformal plan; flattened beam and FFF beam RapidArc Plans for lung SBRT. Methods: Five lung cancer patients treated with 3D non-coplanar SBRT were randomly selected. All the patients were CT scanned with 4DCT to determine the internal target volume. Abdominal compression was applied to minimize respiratory motion for SBRT patients. The prescription dose was 48 Gy in 4 fractions. The PTV coverage was optimized by two groups of objective function: one with high conformity, another mimicking 3D conformal dose distribution with high dose in the center of PTV. Optimization constraints were set to meet the criteria of the RTOG-0915 protocol. All VMAT plans were optimized with the RapidArc technique using four full arcs in Eclipse treatment planning system. The RapidArc SBRT plans with flattened 6MV beam and 6MV FFF beam were generated and dosimetric results were compared with the previous treated 3D non-coplanar plans. Results: All the RapidArc plans with flattened beam and FFF beam had similar results for the PTV and OARs. For the high conformity optimization group, The DVH of PTV exhibited a steep dose fall-off outside the PTV compared to the 3D non-coplanar plan. However, for the group mimicking the 3D conformal target dose distribution, although the PTV is very similar to the 3D conformal plan, the ITV coverage is better than 3D conformal plan. Conclusion: Due to excellent clinical experiences of 3D conformal SBRT treatment, the Rapid Arc optimization mimicking 3D conformal planning may be suggested for clinical use.

  5. Assessment of dosimetric impact of system specific geometric distortion in an MRI only based radiotherapy workflow for prostate

    Science.gov (United States)

    Gustafsson, C.; Nordström, F.; Persson, E.; Brynolfsson, J.; Olsson, L. E.

    2017-04-01

    Dosimetric errors in a magnetic resonance imaging (MRI) only radiotherapy workflow may be caused by system specific geometric distortion from MRI. The aim of this study was to evaluate the impact on planned dose distribution and delineated structures for prostate patients, originating from this distortion. A method was developed, in which computer tomography (CT) images were distorted using the MRI distortion field. The displacement map for an optimized MRI treatment planning sequence was measured using a dedicated phantom in a 3 T MRI system. To simulate the distortion aspects of a synthetic CT (electron density derived from MR images), the displacement map was applied to CT images, referred to as distorted CT images. A volumetric modulated arc prostate treatment plan was applied to the original CT and the distorted CT, creating a reference and a distorted CT dose distribution. By applying the inverse of the displacement map to the distorted CT dose distribution, a dose distribution in the same geometry as the original CT images was created. For 10 prostate cancer patients, the dose difference between the reference dose distribution and inverse distorted CT dose distribution was analyzed in isodose level bins. The mean magnitude of the geometric distortion was 1.97 mm for the radial distance of 200–250 mm from isocenter. The mean percentage dose differences for all isodose level bins, were  ⩽0.02% and the radiotherapy structure mean volume deviations were  MRI system specific distortion in a prostate MRI only radiotherapy workflow, separated from dosimetric effects originating from synthetic CT generation. No clinically relevant dose difference or structure deformation was found when 3D distortion correction and high acquisition bandwidth was used. The method could be used for any MRI sequence together with any anatomy of interest.

  6. Cancer

    Science.gov (United States)

    Cancer begins in your cells, which are the building blocks of your body. Normally, your body forms ... be benign or malignant. Benign tumors aren't cancer while malignant ones are. Cells from malignant tumors ...

  7. Development of the Nation-Wide Dosimetric Monitoring Network in Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Chumak, V.; Boguslavskaya, A.; Musijachenko, A.

    2004-07-01

    Development of the nation-wide network for monitoring and registration of individual doses is being in progress in Ukraine. The need for urgent action is caused by the fact, that despite wide use of nuclear energy and radiation sources in industry and medicine, there is no centralized dose accounting system in Ukraine, existing dosimetry services operate obsolete manual TLD readers and no methodological unity is observed by the dosimetry services. Presently the mixed dosimetric monitoring is practiced in Ukraine. Nuclear power plants and some major nuclear facilities have their own dosimetry services responsible for dosimetric monitoring of workers. Rest of occupationally exposed persons is monitored by territorial dosimetry laboratories affiliated to sanitary and epidemiology supervision bodies. In total these services cover about 38,000 occupationally exposed workers, including 5,500 in medicine, 16,400 employees of five nuclear power plants and about 16,000 workers dealing with other sources of occupational exposure (industry, research, military). It is prescribed by the governmental decree that three-level united state system assigned to covering all aspects of efficient dosimetric monitoring should be established. The tasks of the system, in particular, are: securing methodical unity of individual dosimetric monitoring; scientific and methodological guidance of individual dosimetric control; procurement of common technical policy regarding nomenclature and operation of instrumentation; implementation of quality assurance programs; development and support of information infrastructure for logging, storage and access to data on individual dosimetric monitoring, in particular - keeping the national registry of individual doses; training and certification of personnel engaged in the system of individual dosimetric monitoring. In its development, the national system will be guided by international experience and will be established according to the best practices

  8. Dosimetric coverage of the prostate, normal tissue sparing, and acute toxicity with high-dose-rate brachytherapy for large prostate volumes

    Energy Technology Data Exchange (ETDEWEB)

    Yang, George; Strom, Tobin J.; Shrinath, Kushagra; Mellon, Eric A.; Fernandez, Daniel C.; Biagioli, Matthew C. [Department of Radiation Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL (United States); Wilder, Richard B., E-mail: mcbiagioli@yahoo.com [Cancer Treatment Centers of America, Newnan, GA (United States)

    2015-05-15

    Purpose: to evaluate dosimetric coverage of the prostate, normal tissue sparing, and acute toxicity with HDR brachytherapy for large prostate volumes. Materials and methods: one hundred and two prostate cancer patients with prostate volumes >50 mL (range: 5-29 mL) were treated with high-dose-rate (HDR) brachytherapy ± intensity modulated radiation therapy (IMRT) to 4,500 cGy in 25 daily fractions between 2009 and 2013. HDR brachytherapy monotherapy doses consisted of two 1,350-1,400 cGy fractions separated by 2-3 weeks, and HDR brachytherapy boost doses consisted of two 950-1,150 cGy fractions separated by 4 weeks. Twelve of 32 (38%) unfavorable intermediate risk, high risk, and very high risk patients received androgen deprivation therapy. Acute toxicity was graded according to the Common Terminology Criteria for Adverse Events (CTCAE) version 4. Results: median follow-up was 14 months. Dosimetric goals were achieved in over 90% of cases. Three of 102 (3%) patients developed Grade 2 acute proctitis. No variables were significantly associated with Grade 2 acute proctitis. Seventeen of 102 (17%) patients developed Grade 2 acute urinary retention. American Urological Association (AUA) symptom score was the only variable significantly associated with Grade 2 acute urinary retention (p-0.04). There was no ≥ Grade 3 acute toxicity. Conclusions: dosimetric coverage of the prostate and normal tissue sparing were adequate in patients with prostate volumes >50 mL. Higher pre-treatment AUA symptom scores increased the relative risk of Grade 2 acute urinary retention. However, the overall incidence of acute toxicity was acceptable in patients with large prostate volumes. (author)

  9. Four-Dimensional Computed Tomography Based Respiratory-Gated Radiotherapy with Respiratory Guidance System: Analysis of Respiratory Signals and Dosimetric Comparison

    Directory of Open Access Journals (Sweden)

    Jung Ae Lee

    2014-01-01

    Full Text Available Purpose. To investigate the effectiveness of respiratory guidance system in 4-dimensional computed tomography (4DCT based respiratory-gated radiation therapy (RGRT by comparing respiratory signals and dosimetric analysis of treatment plans. Methods. The respiratory amplitude and period of the free, the audio device-guided, and the complex system-guided breathing were evaluated in eleven patients with lung or liver cancers. The dosimetric parameters were assessed by comparing free breathing CT plan and 4DCT-based 30–70% maximal intensity projection (MIP plan. Results. The use of complex system-guided breathing showed significantly less variation in respiratory amplitude and period compared to the free or audio-guided breathing regarding the root mean square errors (RMSE of full inspiration (P=0.031, full expiration (P=0.007, and period (P=0.007. The dosimetric parameters including V5 Gy, V10 Gy, V20 Gy, V30 Gy, V40 Gy, and V50 Gy of normal liver or lung in 4DCT MIP plan were superior over free breathing CT plan. Conclusions. The reproducibility and regularity of respiratory amplitude and period were significantly improved with the complex system-guided breathing compared to the free or the audio-guided breathing. In addition, the treatment plan based on the 4D CT-based MIP images acquired with the complex system guided breathing showed better normal tissue sparing than that on the free breathing CT.

  10. Comparing Effectiveness of Active and Passive Client Follow-Up Approaches in Sustaining the Continued Use of Long Acting Reversible Contraceptives (LARC) in Rural Punjab: A Multicentre, Non-Inferiority Trial

    Science.gov (United States)

    Hameed, Waqas; Azmat, Syed Khurram; Ali, Moazzam; Ishaque, Muhammad; Abbas, Ghazunfer; Munroe, Erik; Harrison, Rebecca; Shamsi, Wajahat Hussain; Mustafa, Ghulam; Khan, Omar Farooq; Ali, Safdar; Ahmed, Aftab

    2016-01-01

    Background The use of long-acting reversible contraceptive (LARC) methods is very low in Pakistan with high discontinuation rates mainly attributed to method-related side effects. Mixed evidence is available on the effectiveness of different client follow-up approaches used to ensure method continuation. We compared the effectiveness of active and passive follow-up approaches in sustaining the use of LARC—and within ‘active’ follow-up, we further compared a telephone versus home-based approach in rural Punjab, Pakistan. Methods This was a 12-month multicentre non-inferiority trial conducted in twenty-two (16 rural- and 6 urban-based) franchised reproductive healthcare facilities in district Chakwal of Punjab province, between November 2013 and December 2014. The study comprised of three groups of LARC clients: a) home-based follow-up, b) telephone-based follow-up, and c) passive or needs-based follow-up. Participants in the first two study groups received counselling on scheduled follow-up from the field workers at 1, 3, 6, 9, and 12 month post-insertion whereas participants in the third group were asked to contact the health facility if in need of medical assistance relating to LARC method use. Study participants were recruited with equal allocation to each study group, but participants were not randomized. The analyses are based on 1,246 LARC (intra-uterine contraceptive device and implant) users that completed approximately 12-months of follow-up. The non-inferiority margin was kept at five percentage points for the comparison of active and passive follow-up and six percentage points for telephone and home-based approach. The primary outcome was cumulative probability of method continuation at 12-month among LARC users. Results Women recruited in home-based, telephone-based, and passive groups were 400, 419 and 427, respectively. The cumulative probability of LARC continuation at 12 month was 87.6% (95% CI 83.8 to 90.6) among women who received home

  11. Dosimetric evaluation of two treatment planning systems for high dose rate brachytherapy applications

    Energy Technology Data Exchange (ETDEWEB)

    Shwetha, Bondel [Department of Radiation Physics, Kidwai, Memorial Institute of Oncology, Bangalore (India); Ravikumar, Manickam, E-mail: drravikumarm@gmail.com [Department of Radiation Physics, Kidwai, Memorial Institute of Oncology, Bangalore (India); Supe, Sanjay S.; Sathiyan, Saminathan [Department of Radiation Physics, Kidwai, Memorial Institute of Oncology, Bangalore (India); Lokesh, Vishwanath [Department of Radiotherapy, Kidwai, Memorial Institute of Oncology, Bangalore (India); Keshava, Subbarao L. [Department of Radiation Physics, Kidwai, Memorial Institute of Oncology, Bangalore (India)

    2012-04-01

    Various treatment planning systems are used to design plans for the treatment of cervical cancer using high-dose-rate brachytherapy. The purpose of this study was to make a dosimetric comparison of the 2 treatment planning systems from Varian medical systems, namely ABACUS and BrachyVision. The dose distribution of Ir-192 source generated with a single dwell position was compared using ABACUS (version 3.1) and BrachyVision (version 6.5) planning systems. Ten patients with intracavitary applications were planned on both systems using orthogonal radiographs. Doses were calculated at the prescription points (point A, right and left) and reference points RU, LU, RM, LM, bladder, and rectum. For single dwell position, little difference was observed in the doses to points along the perpendicular bisector. The mean difference between ABACUS and BrachyVision for these points was 1.88%. The mean difference in the dose calculated toward the distal end of the cable by ABACUS and BrachyVision was 3.78%, whereas along the proximal end the difference was 19.82%. For the patient case there was approximately 2% difference between ABACUS and BrachyVision planning for dose to the prescription points. The dose difference for the reference points ranged from 0.4-1.5%. For bladder and rectum, the differences were 5.2% and 13.5%, respectively. The dose difference between the rectum points was statistically significant. There is considerable difference between the dose calculations performed by the 2 treatment planning systems. It is seen that these discrepancies are caused by the differences in the calculation methodology adopted by the 2 systems.

  12. Dosimetric evaluation of two treatment planning systems for high dose rate brachytherapy applications.

    Science.gov (United States)

    Shwetha, Bondel; Ravikumar, Manickam; Supe, Sanjay S; Sathiyan, Saminathan; Lokesh, Vishwanath; Keshava, Subbarao L

    2012-01-01

    Various treatment planning systems are used to design plans for the treatment of cervical cancer using high-dose-rate brachytherapy. The purpose of this study was to make a dosimetric comparison of the 2 treatment planning systems from Varian medical systems, namely ABACUS and BrachyVision. The dose distribution of Ir-192 source generated with a single dwell position was compared using ABACUS (version 3.1) and BrachyVision (version 6.5) planning systems. Ten patients with intracavitary applications were planned on both systems using orthogonal radiographs. Doses were calculated at the prescription points (point A, right and left) and reference points RU, LU, RM, LM, bladder, and rectum. For single dwell position, little difference was observed in the doses to points along the perpendicular bisector. The mean difference between ABACUS and BrachyVision for these points was 1.88%. The mean difference in the dose calculated toward the distal end of the cable by ABACUS and BrachyVision was 3.78%, whereas along the proximal end the difference was 19.82%. For the patient case there was approximately 2% difference between ABACUS and BrachyVision planning for dose to the prescription points. The dose difference for the reference points ranged from 0.4-1.5%. For bladder and rectum, the differences were 5.2% and 13.5%, respectively. The dose difference between the rectum points was statistically significant. There is considerable difference between the dose calculations performed by the 2 treatment planning systems. It is seen that these discrepancies are caused by the differences in the calculation methodology adopted by the 2 systems.

  13. Dosimetric comparison of tandem and Ovoids vs. tandem and ring for intracavitary gynecologic applications.

    Science.gov (United States)

    Levin, Daphne; Menhel, Janna; Rabin, Tanya; Pfeffer, M Raphael; Symon, Zvi

    2008-01-01

    We evaluated dosimetric differences in tandem and ovoid (TO) and tandem and ring (TR) gynecologic brachytherapy applicators. Seventeen patients with cervical cancer (Stages II-IV) receiving 3 high-dose-rate (HDR) brachytherapy applications (both TO and TR) were studied. Patients underwent computed tomography (CT) scans with contrast in bladder, and were prescribed 8 Gy to ICRU points A, with additional optimization goals of maintaining the pear-shaped dose distribution and minimizing bladder and rectum doses. Bladder and rectum point doses, mean, and maximum doses were calculated. Total treatment time and volumes treated to 95%, 85%, 50%, and 20% or the prescription dose were compared. There were no significant differences between TO and TR applicators in doses to prescription points or critical organs. However, there were significant differences (p < 0.001) between the applicators in treated volumes and total treatment time. The TO treated larger volumes over a longer time. Within each patient, when the applicators were compared, treated volumes were also found to be significantly different (p < 0.01, chi(2)). Our results demonstrate that the 2 applicators, while delivering the prescribed dose to points A and keeping critical organ doses below tolerance, treat significantly different volumes. It is unclear if this difference is clinically meaningful. TO applicators may be treating surrounding healthy tissue unnecessarily, or TR applicators may be underdosing tumor tissue. Further investigation with appropriate imaging modalities is required for accurate delineation of target volumes. Clearly, the TO and TR are not identical, and should not be used interchangeably without further study.

  14. Assessment of the CALIPSO Lidar 532 nm attenuated backscatter calibration using the NASA LaRC airborne High Spectral Resolution Lidar

    Directory of Open Access Journals (Sweden)

    R. R. Rogers

    2011-02-01

    Full Text Available The Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP instrument on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO spacecraft has provided global, high-resolution vertical profiles of aerosols and clouds since it became operational on 13 June 2006. On 14 June 2006, the NASA Langley Research Center (LaRC High Spectral Resolution Lidar (HSRL was deployed aboard the NASA Langley B-200 aircraft for the first of a series of 86 underflights of the CALIPSO satellite to provide validation measurements for the CALIOP data products. To better assess the range of conditions under which CALIOP data products are produced, these validation flights were conducted under both daytime and nighttime lighting conditions, in multiple seasons, and over a large range of latitudes and aerosol and cloud conditions. This paper presents a quantitative assessment of the CALIOP 532 nm calibration (through the 532 nm total attenuated backscatter using internally calibrated airborne HSRL underflight data and is the most extensive study of CALIOP 532 nm calibration. Results show that HSRL and CALIOP 532 nm total attenuated backscatter agree on average within 2.7% ± 2.1% (CALIOP lower at night and within 2.9% ± 3.9% (CALIOP lower during the day, demonstrating the accuracy of the CALIOP 532 nm calibration algorithms. Additionally, comparisons with HSRL show consistency of the CALIOP calibration before and after the laser switch in 2009 as well as improvements in the daytime version 3.01 calibration scheme compared with the version 2 calibration scheme. Potential biases and uncertainties in the methodology relevant to validating satellite lidar measurements with an airborne lidar system are discussed and found to be less than 4.5% ± 3.2% for this validation effort with HSRL. Results from this study are also compared with prior assessments of the CALIOP 532 nm attenuated backscatter calibration.

  15. Preliminary dosimetric methodology for a new cobalt-60 irradiator for radioinduced necrosis

    Energy Technology Data Exchange (ETDEWEB)

    Moura, Eduardo S.; Mosca, Rodrigo C.; Zeituni, Carlos A.; Rostelato, Maria Elisa C.M.; Mathor, Monica B., E-mail: esmoura@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Sakuraba, Roberto K.; Goncalves, Vinicius D. [Hospital Israelita Albert Einstein (HIAE), Sao Paulo, SP (Brazil)

    2011-07-01

    The use of ionizing radiation in medical procedures, as radiotherapy, is a well-established clinical process and it has been used for several decades with good clinical results and continuous technology development for treatment optimization. On the contrary, some injuries such as necrosis, may occur with patients, due to wrong administration of the absorbed dose or with expected side effects. To evaluate how these injuries could be investigated and how they can be treated, a new Cobalto-60 irradiator was developed to induce radionecrosis in mice. This irradiator is composed by a cylindrical size and it was set up with eleven Cobalt-60 sources aligned in the surface of a cylindrical lead. This alignment guarantees a small dose focal area in a longitudinal table, with proper frames for positioning mice precisely during the irradiations period. The dosimetric procedure will measure the absorbed dose in the dose focal area, delimited the area of irradiation with penumbra regions (gradients absorbed dose profiles) and others anatomical regions of the mice with high radiosensitivity. Possible dosimetric procedures and related devices will be present in this work,. The obtained dosimetric data will be applied to ensure the accurate period of radiation of a given position. This preliminary study assures that the fundamental dosimetric process of this new Cobalt-60 irradiator and it predicates that dosimetric processes area feasible to be conducted. (author)

  16. Characteristic limits of two dosimetric systems used in individual monitoring; Limites caracteristicos de dois sistemas dosimetricos utilizados em monitoracao individual

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, L.S.; Meira-Belo, L.C.; Lacerda, M.A.S., E-mail: masl@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Oliveira, P.M.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte (Brazil)

    2014-07-01

    The characteristic limits: Decision Threshold (y⁎*), Detection Limit (y⧣) and Limits of the Confidence Interval ( y ⊲ and y⊳), were determined for two TLD-100 dosimetric systems, used for individual monitoring. We perform a critical analysis of the suitability of utilizing a dosimetric system for low dose range applications, based on these characteristic values. (author)

  17. Adaptive Radiation: application in lung cancer; Radioterapia adaptativa: aplicacion en cancer de pulmon

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez Mazon, J.; Raba Diez, J. I.; Vazquez Rodriguez, J. a.; Pacheco Baldor, M. T.; Mendiguren Santiago, M. A.; Menendez Garcia, J. C.

    2011-07-01

    The previous updates are a form of adaptive radiation that can be used to account for changes in the size, shape and location of both the tumor and healthy tissue. Are especially useful in the case of lung cancer which typically is associated with significant anatomical changes due to the response to treatment.In the present study, the variation in tumor volume and dosimetric effects from a new CT and replanning during the course of treatment in patients with lung cancer.

  18. The investigation of prostatic calcifications using μ-PIXE analysis and their dosimetric effect in low dose rate brachytherapy treatments using Geant4

    Science.gov (United States)

    Pope, D. J.; Cutajar, D. L.; George, S. P.; Guatelli, S.; Bucci, J. A.; Enari, K. E.; Miller, S.; Siegele, R.; Rosenfeld, A. B.

    2015-06-01

    Low dose rate brachytherapy is a widely used modality for the treatment of prostate cancer. Most clinical treatment planning systems currently in use approximate all tissue to water, neglecting the existence of inhomogeneities, such as calcifications. The presence of prostatic calcifications may perturb the dose due to the higher photoelectric effect cross section in comparison to water. This study quantitatively evaluates the effect of prostatic calcifications on the dosimetric outcome of brachytherapy treatments by means of Monte Carlo simulations and its potential clinical consequences. Four pathological calcification samples were characterised with micro-particle induced x-ray emission (μ-PIXE) to determine their heavy elemental composition. Calcium, phosphorus and zinc were found to be the predominant heavy elements in the calcification composition. Four clinical patient brachytherapy treatments were modelled using Geant4 based Monte Carlo simulations, in terms of the distribution of brachytherapy seeds and calcifications in the prostate. Dose reductions were observed to be up to 30% locally to the calcification boundary, calcification size dependent. Single large calcifications and closely placed calculi caused local dose reductions of between 30-60%. Individual calculi smaller than 0.5 mm in diameter showed minimal dosimetric impact, however, the effects of small or diffuse calcifications within the prostatic tissue could not be determined using the methods employed in the study. The simulation study showed a varying reduction on common dosimetric parameters. D90 showed a reduction of 2-5%, regardless of calcification surface area and volume. The parameters V100, V150 and V200 were also reduced by as much as 3% and on average by 1%. These reductions were also found to relate to the surface area and volume of calcifications, which may have a significant dosimetric impact on brachytherapy treatment, however, such impacts depend strongly on specific factors

  19. Approximated segmentation considering technical and dosimetric constraints in intensity-modulated radiation therapy with electrons

    CERN Document Server

    Kiesel, Antje

    2010-01-01

    In intensity-modulated radiation therapy, optimal intensity distributions of incoming beams are decomposed into linear combinations of leaf openings of a multileaf collimator (segments). In order to avoid inefficient dose delivery, the decomposition should satisfy a number of dosimetric constraints due to suboptimal dose characteristics of small segments. However, exact decomposition with dosimetric constraints is only in limited cases possible. The present work introduces new heuristic segmentation algorithms for the following optimization problem: Find a segmentation of an approximated matrix using only allowed fields and minimize the approximation error. Finally, the decomposition algorithms were implemented into an optimization programme in order to examine the assumptions of the algorithms for a clinical example. As a result, identical dose distributions with much fewer segments and a significantly smaller number of monitor units could be achieved using dosimetric constraints. Consequently, the dose deli...

  20. Transport and dosimetric solutions for the ELIMED laser-driven beam line

    Energy Technology Data Exchange (ETDEWEB)

    Cirrone, G.A.P. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Romano, F. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Medical Physics School, University of Catania, Via S. Sofia 64 - 95125 Catania (Italy); Scuderi, V. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, Na Slovance 2, 182 21 Prague (Czech Republic); Amato, A. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Candiano, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Medical Physics School, University of Catania, Via S. Sofia 64 - 95125 Catania (Italy); Cuttone, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Giove, D. [INFN Sezione di Milano, Via Celoria 16, Milano (Italy); Korn, G.; Krasa, J. [Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, Na Slovance 2, 182 21 Prague (Czech Republic); Leanza, R. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Universitá degli Studi di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Manna, R. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Maggiore, M. [INFN-LNL, Viale dell' Universitá 2 - 35020 Legnaro (PD) (Italy); Marchese, V. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Margarone, D. [Institute of Physics ASCR, v.v.i. (FZU), ELI-Beamlines Project, Na Slovance 2, 182 21 Prague (Czech Republic); Milluzzo, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Universitá degli Studi di Catania, Dipartimento di Fisica e Astronomia, Via S. Sofia 64, Catania (Italy); Petringa, G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Sabini, M.G. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Azienda Ospedaliera Cannizzaro, Via Messina 829 - 95100 Catania (Italy); Schillaci, F. [INFN-LNS, Via S. Sofia 62 - 95125 Catania (Italy); Medical Physics School, University of Catania, Via S. Sofia 64 - 95125 Catania (Italy); and others

    2015-10-01

    Within 2017, the ELIMED (ELI-Beamlines MEDical applications) transport beam-line and dosimetric systems for laser-generated beams will be installed at the ELI-Beamlines facility in Prague (CZ), inside the ELIMAIA (ELI Multidisciplinary Applications of laser–Ion Acceleration) interaction room. The beam-line will be composed of two sections: one in vacuum, devoted to the collecting, focusing and energy selection of the primary beam and the second in air, where the ELIMED beam-line dosimetric devices will be located. This paper briefly describes the transport solutions that will be adopted together with the main dosimetric approaches. In particular, the description of an innovative Faraday Cup detector with its preliminary experimental tests will be reported.

  1. Dosimetric response of united, commercially available CTA foils for sup 6 sup 0 Co gamma rays

    CERN Document Server

    Peimel-Stuglik, Z

    2001-01-01

    The usefulness of two kinds of untinted CTA foils: Fuji CTR-125 dosimetric foil and technical CTA-T foil, produced by 'Zaklady Chemiczne, 'Gorzow Wielkopolski' as support for light-sensitive layers of amateur photo-films, for sup 6 sup 0 Co gamma ray dosimetry was investigated. In spite of rather bad physical parameters of the technical foil (spread of foil thickness, high and different initial absorbance) the dosimetric response of both foils for sup 6 sup 0 Co gamma rays was similar. The CTA-T foil can be used for routine dosimetry providing that dosimetric signals have to be calculated exactly as recommended by the ASTM (American Society for Testing and Materials) standard, i.e. as the difference of absorbance of irradiated and (the same) non-irradiated foil. Any other approach may lead to high errors of dose evaluation. The last is true also for other CTA foils, especially after long self-life.

  2. SU-E-J-228: MRI-Based Planning: Dosimetric Feasibility of Dose Painting for ADCDefined Intra-Prostatic Tumor

    Energy Technology Data Exchange (ETDEWEB)

    Chen, X; Dalah, E; Prior, P; Lawton, C; Li, X [Medical College of Wisconsin, Milwaukee, WI (United States)

    2015-06-15

    Purpose: Apparent diffusion coefficient (ADC) map may help to delineate the gross tumor volume (GTV) in prostate gland. Dose painting with external beam radiotherapy for GTV might increase the local tumor control. The purpose of this study is to explore the maximum boosting dose on GTV using VMAT without sacrificing sparing of organs at risk (OARs) in MRI based planning. Methods: VMAT plans for 5 prostate patients were generated following the commonly used dose volume (DV) criteria based on structures contoured on T2 weighted MRI with bulk electron density assignment using electron densities derived from ICRU46. GTV for each patient was manually delineated based on ADC maps and fused to T2-weighted image set for planning study. A research planning system with Monte Carlo dose engine (Monaco, Elekta) was used to generate the VMAT plans with boosting dose on GTV gradually increased from 85Gy to 100Gy. DV parameters, including V(boosting-dose) (volume covered by boosting dose) for GTV, V75.6Gy for PTV, V45Gy, V70Gy, V72Gy and D1cc (Maximum dose to 1cc volume) for rectum and bladder, were used to measure plan quality. Results: All cases achieve at least 99.0% coverage of V(boosting-dose) on GTV and 95% coverage of V75.6Gy to the PTV. All the DV criteria, V45Gy≤50% and V70Gy≤15% for bladder and rectum, D1cc ≤77Gy (Rectum) and ≤80Gy (Bladder), V72Gy≤5% (rectum and bladder) were maintained when boosting GTV to 95Gy for all cases studied. Except for two patients, all the criteria were also met when the boosting dose goes to 100Gy. Conclusion: It is dosimetrically feasible safe to boost the dose to at least 95Gy to ADC defined GTV in prostate cancer using MRI guided VMAT delivery. Conclusion: It is dosimetrically feasible safe to boost the dose to at least 95Gy to ADC defined GTV in prostate cancer using MRI guided VMAT delivery. This research is partially supported by Elekta Inc.

  3. Dosimetric Analysis of Radiation-induced Gastric Bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Mary, E-mail: maryfeng@umich.edu [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Normolle, Daniel [Department of Biostatistics, University of Pittsburgh, Pittsburgh, Pennsylvania (United States); Pan, Charlie C. [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Dawson, Laura A. [Department of Radiation Oncology, Princess Margaret Hospital, University of Toronto, Toronto, Ontario (Canada); Amarnath, Sudha [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Ensminger, William D. [Department of Internal Medicine, Division of Hematology Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States); Lawrence, Theodore S.; Ten Haken, Randall K. [Department of Radiation Oncology, University of Michigan School of Medicine, Ann Arbor, Michigan (United States)

    2012-09-01

    Purpose: Radiation-induced gastric bleeding has been poorly understood. In this study, we described dosimetric predictors for gastric bleeding after fractionated radiation therapy. Methods and Materials: The records of 139 sequential patients treated with 3-dimensional conformal radiation therapy (3D-CRT) for intrahepatic malignancies were reviewed. Median follow-up was 7.4 months. The parameters of a Lyman normal tissue complication probability (NTCP) model for the occurrence of {>=}grade 3 gastric bleed, adjusted for cirrhosis, were fitted to the data. The principle of maximum likelihood was used to estimate parameters for NTCP models. Results: Sixteen of 116 evaluable patients (14%) developed gastric bleeds at a median time of 4.0 months (mean, 6.5 months; range, 2.1-28.3 months) following completion of RT. The median and mean maximum doses to the stomach were 61 and 63 Gy (range, 46-86 Gy), respectively, after biocorrection of each part of the 3D dose distributions to equivalent 2-Gy daily fractions. The Lyman NTCP model with parameters adjusted for cirrhosis predicted gastric bleed. Best-fit Lyman NTCP model parameters were n=0.10 and m=0.21 and with TD{sub 50} (normal) = 56 Gy and TD{sub 50} (cirrhosis) = 22 Gy. The low n value is consistent with the importance of maximum dose; a lower TD{sub 50} value for the cirrhosis patients points out their greater sensitivity. Conclusions: This study demonstrates that the Lyman NTCP model has utility for predicting gastric bleeding and that the presence of cirrhosis greatly increases this risk. These findings should facilitate the design of future clinical trials involving high-dose upper abdominal radiation.

  4. SU-E-T-620: Dosimetric Compliance Study for a New Prostate Protocol of Combined High Dose Rate Brachytherapy and Stereotactic Body Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Peng, C; Giaddui, T; Den, R; Harrison, A; Yu, Y [Thomas Jefferson University, Philadelphia, PA (United States)

    2014-06-15

    Purpose: To investigate the adherence of treatment plans of prostate cancer patients with the dosimetric compliance criteria of the new in house phase I trial of high dose rate (HDR) brachytherapy combined with stereotactic body radiotherapy (SBRT) for intermediate risk prostate cancer patients. Methods: Ten prostate cancer patients were treated using this trial. They received one fraction of HDR to 15Gy, followed by external beam(EB) boost of 3.2Gy(Level 1, five patients) or 3.94Gy(level 2, five patients) per fraction for 10 or 7 fractions, respectively, both equivalent to EB treatments of 113.5Gy in 2Gy fractions. The EB plans were either IMRT or VMAT plans. DVH analysis was performed to verify the adherence of treatment plans to the dosimetric criteria of the trial. Results: For Level 1 patients, target coverage were adequate, with CTV V32Gy(%) of 99.0±1.0 (mean ± 1 standard deviation), and PTV V31Gy(%) of 99.6±0.3. PTV V32.9Gy(%) is 1.4±3.1 and PTVmax is 32.9±0.2Gy. Rectum, bladder and femoral heads sparing were well within protocol criteria. For Level 2 patients, CTV V27.6Gy(%) is 98.7±1.8; PTV V26.7Gy(%) is 99.0±1.4. PTV V28.4Gy(%) is 1.3±1.4, with three patients having minor deviation from protocol. Again critical structures were spared compliant to the protocol. The analysis of HDR plans show similar results, with adequate dose coverage to the prostate and sparing of critical structures including urethra and rectum. V100(%) and V90(%) of prostate are 96.0±1.1 and 98.9±0.5. Urethra D10(%) is 113.1±2.9. Rectum V80(cc) is 1.4±0.5. Hotspot in prostate is substantially higher than what the protocol specifies. But the criteria for hotspot are only guidelines, serving to lower the dose to urethra . Conclusion: This new high biological equivalent dose prostate trial has been carried out successfully for ten patients. Based on dosimetric analysis, all HDR and external plans were compliant to the protocol criteria, with only minor deviations.

  5. Cancer

    Science.gov (United States)

    ... uses a surgical tool to remove the tumor.Mohs' surgery. Layers of cancer cells are removed one ... usually have not been approved by the U.S. Food and Drug Administration (FDA). The medicine may have ...

  6. 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)

  7. Dosimetric impact of orthopedic metal artifact reduction (O-MAR) on Spine SBRT patients.

    Science.gov (United States)

    Shen, Zhilei Liu; Xia, Ping; Klahr, Paul; Djemil, Toufik

    2015-09-08

    The dosimetric impact of orthopedic metal artifact reduction (O-MAR) on spine SBRT patients has not been comprehensively studied, particularly with spinal prostheses in high-dose gradient regions. Using both phantom and patient datasets, we investigated dosimetric effects of O-MAR in combination of various metal locations and dose calculation algorithms. A physical phantom, with and without a titanium insert, was scanned. A clinical patient plan was applied to the artifact-free reference, non-O-MAR, and O-MAR phantom images with the titanium located either inside or outside of the tumor. Subsequently, five clinical patient plans were calculated with pencil beam and Monte Carlo (iPlan) on non-O-MAR and O-MAR patient images using an extended CT-density table. The dose differences for phantom plans and patient plans were analyzed using dose distributions, dose-volume histograms (DVHs), gamma index, and selected dosimetric endpoints. From both phantom plans and patient plans, O-MAR did not affect dose distributions and DVHs while minimizing metal artifacts. Among patient plans, we found that, when the same dose calculation method was used, the difference in the dosimetric endpoints between non-O-MAR and O-MAR datasets were small. In conclusion, for spine SBRT patients with spinal prostheses, O-MAR image reconstruction does not affect dose calculation accuracy while minimizing metal artifacts. Therefore, O-MAR images can be safely used for clinical spine SBRT treatment planning.

  8. Dosimetric and Deformation Effects of Image-Guided Interventions during Stereotactic Body Radiation Therapy of the Prostate using an Endorectal Balloon

    CERN Document Server

    Jones, Bernard L; Diot, Quentin; Kavanagh, Brian; Timmerman, Robert D; Miften, Moyed

    2013-01-01

    During Stereotactic Body Radiotherapy (SBRT) for the treatment of prostate cancer, an inflatable endorectal balloon (ERB) may be used to reduce motion of the target and reduce the dose to the posterior rectal wall. This work assessed the dosimetric impact of manual interventions on ERB position in patients receiving prostate SBRT and investigated the impact of ERB interventions on prostate shape. Daily kilovoltage (kV) cone-beam computed tomography (CBCT) imaging was performed to localize the PTV, and an automated fusion with the planning images yielded displacements required for PTV re-localization. When the ERB volume and/or position were judged to yield inaccurate repositioning, manual adjustment (ERB re-inflation and/or repositioning) was performed. Based on all 59 CBCT image sets acquired, a deformable registration algorithm was used to determine the dose received by, displacement of, and deformation of the prostate, bladder, and anterior rectal wall. This dose tracking methodology was applied to images ...

  9. The dosimetric impact of inversely optimized arc radiotherapy plan modulation for real-time dynamic MLC tracking delivery

    DEFF Research Database (Denmark)

    Falk, Marianne; Larsson, Tobias; Keall, Paul

    2012-01-01

    Purpose: Real-time dynamic multileaf collimator (MLC) tracking for management of intrafraction tumor motion can be challenging for highly modulated beams, as the leaves need to travel far to adjust for target motion perpendicular to the leaf travel direction. The plan modulation can be reduced...... on the dosimetric accuracy of MLC tracking delivery. Specifically, the possibility of predicting the accuracy of MLC tracking delivery based on the plan modulation was investigated. Methods: Inversely optimized arc radiotherapy plans were created on CT-data of three lung cancer patients. For each case, five plans...... with a single 358° arc were generated with LPC priorities of 0 (no LPC), 0.25, 0.5, 0.75, and 1 (highest possible LPC), respectively. All the plans had a prescribed dose of 2 Gy × 30, used 6 MV, a maximum dose rate of 600 MU/min and a collimator angle of 45° or 315°. To quantify the plan modulation, an average...

  10. Neoadjuvant chemotherapy first, followed by chemoradiation and then surgery, in the management of locally advanced rectal cancer.

    Science.gov (United States)

    Cercek, Andrea; Goodman, Karyn A; Hajj, Carla; Weisberger, Emily; Segal, Neil H; Reidy-Lagunes, Diane L; Stadler, Zsofia K; Wu, Abraham J; Weiser, Martin R; Paty, Philip B; Guillem, Jose G; Nash, Garrett M; Temple, Larissa K; Garcia-Aguilar, Julio; Saltz, Leonard B

    2014-04-01

    Standard therapy for locally advanced rectal cancer (LARC) is preoperative chemoradiotherapy and postoperative chemotherapy. At Memorial Sloan-Kettering Cancer Center (MSKCC) the authors began offering FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin) as initial treatment for patients with high-risk LARC to target micrometastases while treating the primary tumor. The purpose of this study is to report the safety and efficacy of initial FOLFOX given before chemoradiotherapy on tumor downsizing and pathologic complete response (pathCR) in LARC. The records of patients with stage II/III rectal cancer treated at MSKCC between 2007 and 2012 were reviewed. Of approximately 300 patients with LARC treated at MSKCC, 61 received FOLFOX as initial therapy. Of these 61 patients, 57 received induction FOLFOX (median 7 cycles) followed by chemoradiation, and 4 experienced an excellent response, declined chemoradiation, and underwent total mesorectal excision (TME). Twelve of the 61 patients did not undergo TME: 9 had a complete clinical response (CCR), 1 declined despite persistent tumor, 1 declined because of comorbidities, and 1 developed metastatic disease. Among the 61 patients receiving initial FOLFOX, 22 (36%) had either a pathCR (n=13) or a CCR (n=9). Of the 49 patients who underwent TME, all had R0 resections and 23 (47%) had tumor response greater than 90%, including 13 (27%) who experienced a pathCR. Of the 28 patients who received all 8 cycles of FOLFOX, 8 experienced a pathCR (29%) and 3 a CCR (11%). No serious adverse events occurred that required a delay in treatment during FOLFOX or chemoradiation. FOLFOX and chemoradiation before planned TME results in tumor regression, a high rate of delivery of planned therapy, and a substantial rate of pathCRs, and offers a good platform for nonoperative management in select patients.

  11. SU-E-T-335: Dosimetric Investigation of An Advanced Rotating Gamma Ray System for Imaged Guided Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ma, C; Eldib, A; Chibani, O; Li, J; Chen, L [Fox Chase Cancer Center, Philadelphia, PA (United States); Li, C [Renmin Hospital of Wuhan University, Wuhan (China); Mora, G [Universidade de Lisboa, Codex, Lisboa (Portugal)

    2015-06-15

    Purpose: Co-60 beams have unique dosimetric properties for cranial treatments and thoracic cancers. The conventional concern about the high surface dose is overcome by modern system designs with rotational treatment techniques. This work investigates a novel rotational Gamma ray system for image-guided, external beam radiotherapy. Methods: The CybeRT system (Cyber Medical Corp., China) consists of a ring gantry with either one or two treatment heads containing a Gamma source and a multileaf collimator (MLC). The MLC has 60 paired leaves, and the maximum field size is either 40cmx40cm (40 pairs of 0.5cm central leaves, 20 pairs of 1cm outer leaves), or 22cmx40cm (32 pairs of 0.25cm central leaves, 28 pairs of 0.5cm outer leaves). The treatment head(s) can swing 35° superiorly and 8° inferiorly, allowing a total of 43° non-coplanar beam incident. The treatment couch provides 6-degrees-of-freedom motion compensation and the kV cone-beam CT system has a spatial resolution of 0.4mm. Monte Carlo simulations were used to compute dose distributions and compare with measurements. A retrospective study of 98 previously treated patients was performed to compare CybeRT with existing RT systems. Results: Monte Carlo results confirmed the CybeRT design parameters including output factors and 3D dose distributions. Its beam penumbra/dose gradient was similar to or better than that of 6MV photon beams and its isocenter accuracy is 0.3mm. Co-60 beams produce lower-energy secondary electrons that exhibit better dose properties in low-density lung tissues. Because of their rapid depth dose falloff, Co-60 beams are favorable for peripheral lung tumors with half-arc arrangements to spare the opposite lung and critical structures. Superior dose distributions were obtained for head and neck, breast, spine and lung tumors. Conclusion: Because of its accurate dose delivery and unique dosimetric properties of C-60 sources, CybeRT is ideally suited for advanced SBRT as well as

  12. Dosimetric characterization of a 2-D array of 223 solid state detectors for daily morning checks in Tomo Therapy equipment; Caracterizacion dosimetrica de un arreglo 2D de 223 detectores de estado solido para verificaciones matutinas diarias en un equipo de Tomo Terapia

    Energy Technology Data Exchange (ETDEWEB)

    Reyes S, U.; Sosa A, M. [Universidad de Guanajuato, Division de Ciencias e Ingenieria, Lomas del Bosque No. 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Vega C, H. R., E-mail: uvaldoreyes@hotmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    Tomo Therapy is a new technique for the cancer treatment; however, the equipment must meet nearly all mechanical and dosimetric characteristics of a conventional linear accelerator for medical use. Daily quality controls are vital to the good operation of the equipment and thus guarantee excellent quality in the daily delivery of treatments. This paper presents the procedure of the dosimetric characterization of a two-dimensional array of 223 solid state detectors, called TomoDose of the Sun Nuclear Company. Dosimetric important criteria are established to perform these checks quickly and accurately. Dosimetric tests proposed are: repeatability, linearity, dependence of Sad and SSD. Some results are compared with readings of the ionization chamber Exradim A1SL. Finally the results of 30 consecutive days are presented to establish criteria for evidence of dose, field size, symmetry and flattening of the radiation beam on Tomo Therapy equipment. Expected values for daily verification are: Dose constancy of 194.89 c Gy, σ= 1.31 c Gy, symmetry in the X axis of -0.19 %, σ=0.08 %, symmetry in the Y axis of 1.66 %, σ= 0.05 %, flattened in the X axis of 25.71 %, σ= 0.05 % and flattened in the Y axis of 6.41 %, σ= 10.23 %. Field sizes obtained were 40.45 cm in the X axis and 5.10 on the Y axis, with standard deviations of 0.02 cm and 0.01 cm, respectively. TomoDose dosimetric values, compared to the values obtained with ionization chamber, presented differences smaller than 2%. (Author)

  13. Technological advances in radiotherapy of rectal cancer

    DEFF Research Database (Denmark)

    Appelt, Ane L; Sebag-Montefiore, David

    2016-01-01

    PURPOSE OF REVIEW: This review summarizes the available evidence for the use of modern radiotherapy techniques for chemoradiotherapy for rectal cancer, with specific focus on intensity-modulated radiotherapy (IMRT) and volumetric arc therapy (VMAT) techniques. RECENT FINDINGS: The dosimetric....... Overall results are encouraging, as toxicity levels - although varying across reports - appear lower than for 3D conformal radiotherapy. Innovative treatment techniques and strategies which may be facilitated by the use of IMRT/VMAT include simultaneously integrated tumour boost, adaptive treatment...

  14. A dosimetric characterization of a novel linear accelerator collimator

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, C. M.; Weston, S. J., E-mail: steve.weston@leedsth.nhs.uk; Cosgrove, V. C. [Leeds Cancer Centre, Bexley Wing, St. James’ University Hospital, Leeds LS9 7TF (United Kingdom); Thwaites, D. I. [Institute of Medical Physics, School of Physics, University of Sydney, Sydney NSW 2006, Australia and Division of Medical Physics, Leeds Institute of Genetics, Health and Therapeutics, University of Leeds, Leeds LS2 9JT (United Kingdom)

    2014-03-15

    Purpose: The aim of this work is to characterize a new linear accelerator collimator which contains a single pair of sculpted diaphragms mounted orthogonally to a 160 leaf multileaf collimator (MLC). The diaphragms have “thick” regions providing full attenuation and “thin” regions where attenuation is provided by both the leaves and the diaphragm. The leaves are mounted on a dynamic leaf guide allowing rapid leaf motion and leaf travel over 350 mm. Methods: Dosimetric characterization, including assessment of leaf transmission, leaf tip transmission, penumbral width, was performed in a plotting tank. Head scatter factor was measured using a mini-phantom and the effect of leaf guide position on output was assessed using a water phantom. The tongue and groove effect was assessed using multiple exposures on radiochromic film. Leaf reproducibility was assessed from portal images of multiple abutting fields. Results: The maximum transmission through the multileaf collimator is 0.44% at 6 MV and 0.52% at 10 MV. This reduced to 0.22% and 0.27%, respectively, when the beam passes through the dynamic leaf guide in addition to the MLC. The maximum transmission through the thick part of the diaphragm is 0.32% and 0.36% at 6 and 10 MV. The combination of leaf and diaphragm transmission ranges from 0.08% to 0.010% at 6 MV and 0.10% to 0.14% depending on whether the shielding is through the thick or thin part of the diaphragm. The off-axis intertip transmission for a zero leaf gap is 2.2% at 6 and 10 MV. The leaf tip penumbra for a 100 × 100 mm field ranges from 5.4 to 4.3 mm at 6 and 10 MV across the full range of leaf motion when measured in the AB direction, which reduces to 4.0–3.4 mm at 6 MV and 4.5–3.8 mm at 10 MV when measured in the GT direction. For a 50 × 50 mm field, the diaphragm penumbra ranges from 4.3 to 3.7 mm at 6 MV and 4.5 to 4.1 mm at 10 MV in the AB direction and 3.7 to 3.2 mm at 6 MV and 4.2 to 3.7 mm when measured in the GT direction. The

  15. Dosimetric and radiobiologic comparison of 3D conformal versus intensity modulated planning techniques for prostate bed radiotherapy.

    Science.gov (United States)

    Koontz, Bridget F; Das, Shiva; Temple, Kathy; Bynum, Sigrun; Catalano, Suzanne; Koontz, Jason I; Montana, Gustavo S; Oleson, James R

    2009-01-01

    Adjuvant radiotherapy for locally advanced prostate cancer improves biochemical and clinical disease-free survival. While comparisons in intact prostate cancer show a benefit for intensity modulated radiation therapy (IMRT) over 3D conformal planning, this has not been studied for post-prostatectomy radiotherapy (RT). This study compares normal tissue and target dosimetry and radiobiological modeling of IMRT vs. 3D conformal planning in the postoperative setting. 3D conformal plans were designed for 15 patients who had been treated with IMRT planning for salvage post-prostatectomy RT. The same computed tomography (CT) and target/normal structure contours, as well as prescription dose, was used for both IMRT and 3D plans. Normal tissue complication probabilities (NTCPs) were calculated based on the dose given to the bladder and rectum by both plans. Dose-volume histogram and NTCP data were compared by paired t-test. Bladder and rectal sparing were improved with IMRT planning compared to 3D conformal planning. The volume of the bladder receiving at least 75% (V75) and 50% (V50) of the dose was significantly reduced by 28% and 17%, respectively (p = 0.002 and 0.037). Rectal dose was similarly reduced, V75 by 33% and V50 by 17% (p = 0.001 and 0.004). While there was no difference in the volume of rectum receiving at least 65 Gy (V65), IMRT planning significant reduced the volume receiving 40 Gy or more (V40, p = 0.009). Bladder V40 and V65 were not significantly different between planning modalities. Despite these dosimetric differences, there was no significant difference in the NTCP for either bladder or rectal injury. IMRT planning reduces the volume of bladder and rectum receiving high doses during post-prostatectomy RT. Because of relatively low doses given to the bladder and rectum, there was no statistically significant improvement in NTCP between the 3D conformal and IMRT plans.

  16. Avaliação dosimétrica de uma combinação de aplicadores para braquiterapia de tumores do colo uterino com acometimento da porção distal da vagina Dosimetric evaluation of a combination of brachytherapy applicators for uterine cervix cancer with involvement of the distal vagina

    Directory of Open Access Journals (Sweden)

    Roger Guilherme Rodrigues Guimarães

    2009-08-01

    Full Text Available OBJETIVO: Avaliar uma alternativa de braquiterapia para tumores do colo uterino acometendo a porção distal da vagina, sem aumentar os riscos de toxicidade. MATERIAIS E MÉTODOS: Estudo teórico comparando três diferentes aplicadores de braquiterapia intracavitária de alta taxa de dose: sonda intrauterina e cilindro vaginal (SC; sonda e anel associado ao cilindro vaginal (SA+C e um aplicador virtual com sonda, anel e cilindro vaginal em um único conjunto (SAC. Foram prescritas doses de 7 Gy no ponto A e 5 Gy na superfície ou a 5 mm de profundidade na mucosa vaginal, mantendo as doses nos pontos de reto, bexiga e sigmoide abaixo dos limites de tolerância. Foram comparados os volumes englobados pelas isodoses de 50% (V50, 100% (V100, 150% (V150 e 200% (V200, respectivamente. RESULTADOS: Tanto SA+C quanto SAC apresentaram melhor distribuição de dose quando comparados ao aplicador SC. A distribuição de dose obtida com SA+C foi semelhante à do aplicador SAC, sendo V150 e V200 cerca de 50% maiores para SA+C, todavia, dentro do cilindro. CONCLUSÃO: A utilização de SA+C em uma única aplicação em dois tempos pode ser uma alternativa de tratamento para pacientes que apresentam tumores de colo uterino com acometimento distal da vagina.OBJECTIVE: To evaluate an alternative brachytherapy technique for uterine cervix cancer involving the distal vagina, without increasing the risk of toxicity. MATERIALS AND METHODS: Theoretical study comparing three different high-dose rate intracavitary brachytherapy applicators: intrauterine tandem and vaginal cylinder (TC; tandem/ring applicator combined with vaginal cylinder (TR+C; and a virtual applicator combining both the tandem/ring and vaginal cylinder in a single device (TRC. Prescribed doses were 7 Gy at point A, and 5 Gy on the surface or at a 5 mm depth of the vaginal mucosa. Doses delivered to the rectum, bladder and sigmoid colon were kept below the tolerance limits. Volumes covered by the

  17. 宫颈癌术后三维适形放疗和共面等分设野调强放疗计划的对比分析%Dosimetric study of postoperative 3-dimensional conformal radiotherapy and coplanar decile intensity-modulated radiotherapy for cervical cancer

    Institute of Scientific and Technical Information of China (English)

    蒋军; 张利文; 廖珊; 黄荣

    2012-01-01

    目的 探讨宫颈癌术后三维适形放射治疗(3D-CRT)和共面等分设野调强放射治疗(IMRT)计划靶区及其周围危及器官受照剂量的差异.方法 随机选择10例宫颈癌术后患者,进行CT扫描、靶区和危及器官的勾画,处方剂量50 Gy.分别进行3D-CRT和共面等分设野IMRT计划设计,计算靶区剂量均匀度指数(HI)、适形度指数(CI)、最大受照剂量、最小受照剂量、平均受照剂量和危及器官照射体积等并对结果进行比较分析.结果 5F-IMRT、7F-IMRT和9F-IMRT在靶区适形度方面明显优于3D-CRT;在危及器官(膀胱V30 、V40 、V50,小肠V50和直肠V30、V40、V50)保护方面,5F-IMRT、7F-IMRT和9F-IMRT明显优于3D-CRT,P<0.05.而各IMRT计划之间差异无统计学意义,P>0.05.结论 宫颈癌术后辅助放疗共面等分IMRT计划无论在靶区适形度还是正常组织保护方面均优于3D-CRT,同时也证实7野或9野IMRT未必较5野获益更多.5野与7、9野的IMRT相比、在治疗时间及费用方面有独特的优势,值得在临床上推广.%Objective To compare the difference of the dose distribution in clinical target volume and organ at risk (OAR) between coplanar decile field intensity-modulated radiotherapy (IMRT) and conventional three-dimensional conformal radiotherapy (3D-CRT) for postoperative radiotherapy of cervical cancer. Methods Ten postoperative patients with cervical cancer were selected randomly to undergo CT scan and planning target volume (PTV) and OAR contouring. 3D-CRT and coplanar decile IMRT planning was performed for each patient with a prescribed dose of 50 Gy. The homogeneity index (HI), conformity index (CI), maximum dose, minimum dose, mean dose of PTV, and irradiated volume of OARs were calculated and the results were compared. Results 5-field IMRT, 7-field IMRT and 9-field IMRT plans had a significant better conformity index (CI) of PTV compared with 3D-CRT (P0.05). Conclusion Coplanar decile IMRT plans is superior

  18. 宫颈癌术后盆腔容积调强弧形治疗与固定野调强放疗计划的剂量学研究%Dosimetric study of volumetric intensity-modulated arc therapy and fixed field intensity-modulated radiotherapy for cervix cancer

    Institute of Scientific and Technical Information of China (English)

    杨波; 庞廷田; 孙显松; 胡克; 邱杰; 张福泉

    2012-01-01

    Objective To compare the dosimetry characteristics of volumetric intensity-modulated arc therapy (VIMAT) and fixed field intensity-modulated radiation therapy (FF-IMRT) for cervix cancer.Methods CT images of 13 patients with cervix uteri cancer were transferred into Eclipse planning system.FF-IMRT and VIMAT plans were optimized on an Eclipse treatment planning system using beam data generated for Varian trilogy linear accelerator.Planning target volume (PTV) and organs at risk were evaluated with dose-volume histogram.To appraise the difference between the techniques,the paired t-test was applied.Results Compared with the FF-IMRT plans,PTV95% coverage of VIMAT plan group increased (t =9.84,P =0.000),PTV110% became lower (t =-3.72,P =0.003),Dmax decreased (t =-3.51,P=0.005),and CI became worser (t=5.39,P=0.000).PTV105%,Dmean,and HI had no difference (t =-0.02,-0.60,1.13,P =0.842,0.560,0.283).V30 of the bladder was reduced by about 10% (t =-4.99,P =0.000),and Dmean and Dmax were 1.4 Gy and 1.5 Gy lower respectively (t =-3.65,-18.03,P =0.004,0.000) ;V40 of the rectum was reduced by about 10% (t =-2.99,P =0.012),and Dmean and Dmax were reduced by 0.6 Gy,0.8 Gy respectively (t =-2.98,-4.05,P =0.013,0.002) ;V30,V40 and V50 of the small intestine were reduced by 16%,10% and 11% (t =-10.85,-4.74,-8.66,P =0.000,0.001,0.000),and Dmax was reduced by 0.8 Gy (t =-9.45,P =0.000) ; V30,V40 and V50 of the bone marrow were reduced by 26%,19% and 16% (t =-22.10,-10.19,-4.04,P =0.000,0.000,0.002),and Dmean reduced by 1.9 Gy (t =-16.21,P =0.000) ; D5 of the left and right femoral heads were reduced by 1.6 Gy and 2.7 Gy (t =-2.89,-6.22,P =0.015,0.000).Dmax of the caudate equine was reduced by 1.5 Gy (t=-4.80,P=0.001).V20,V30,V40 and V50 of the body were reduced by 18%,18%,4% and3%(t=-7.52,-11.75,-6.26,-6.94,P=0.000,0.000,0.000,0.000).Dmean and Dmax of the body decreased by 1.0 Gy and 0.4 Gy (t=-3.72,-3.51,P=0.000,0.005).Average machine unit (MU) decreased

  19. CANCER

    Directory of Open Access Journals (Sweden)

    N. Kavoussi

    1973-09-01

    Full Text Available There are many carcinogenetic elements in industry and it is for this reason that study and research concerning the effect of these materials is carried out on a national and international level. The establishment and growth of cancer are affected by different factors in two main areas:-1 The nature of the human or animal including sex, age, point and method of entry, fat metabolism, place of agglomeration of carcinogenetic material, amount of material absorbed by the body and the immunity of the body.2 The different nature of the carcinogenetic material e.g. physical, chemical quality, degree of solvency in fat and purity of impurity of the element. As the development of cancer is dependent upon so many factors, it is extremely difficult to determine whether a causative element is principle or contributory. Some materials are not carcinogenetic when they are pure but become so when they combine with other elements. All of this creates an industrial health problem in that it is almost impossible to plan an adequate prevention and safety program. The body through its system of immunity protects itself against small amounts of carcinogens but when this amount increases and reaches a certain level the body is not longer able to defend itself. ILO advises an effective protection campaign against cancer based on the Well –equipped laboratories, Well-educated personnel, the establishment of industrial hygiene within factories, the regular control of safety systems, and the implementation of industrial health principles and research programs.

  20. A dosimetric comparison of intensity modulated and volumetric arc radiation therapy for gastric cancer%静态调强与容积调强技术在胃癌术后放射治疗中的剂量学比较

    Institute of Scientific and Technical Information of China (English)

    曾建霜; 肖江洪; 李志平

    2013-01-01

    Objective To compare radiotherapy plans for gastric cancer using IMRT and single and (or) double-arc VMAT techniques.Methods 29 patients were replanned by 5-filed IMRT,7-field IMRT,SA-VMAT and DA-VMAT.Dose-volume histogram (DVH) statistics were analyzed to compare treatment plans.Results The DA-VMAT plans are better than the other methods in terms of PTV dose and OARs except for the liver.For the liver,5F-IMRT showed a slight advantage in V30 and mean dose to normal liver over that in DA-VMAT.Conclusions DA-VMAT provided better tumor coverage compared with 5F-IMRT,7F-IMRT and SA-VMAT but DA-VMAT had no advantage of liver protection over the 5F-IMRT.Further studies are needed to establish treatment outcome differences between the four technologies.%目的 比较胃癌患者手术后静态调强放射治疗(IMRT)与容积调强放射治疗(VMAT)的剂量学差异,为临床应用提供参考.方法 选取29例胃癌术后患者,每例患者分别制定5野IM-RT、7野IMRT、单弧VMAT和双弧VMAT四种治疗计划,评估靶区和危及器官的剂量分布情况.结果 DA-VMAT在靶区剂量均匀性、适形度和肾脏保护方面较优,但在肝脏保护上逊于5F-IMRT.结论 综合考虑靶区适形度、剂量均匀性、治疗效率和对肾脏的保护,DA-VMAT在胃癌放射治疗中具有放射物理的优势.

  1. Near Real-Time Assessment of Anatomic and Dosimetric Variations for Head and Neck Radiation Therapy via Graphics Processing Unit–based Dose Deformation Framework

    Energy Technology Data Exchange (ETDEWEB)

    Qi, X. Sharon, E-mail: xqi@mednet.ucla.edu [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Santhanam, Anand; Neylon, John; Min, Yugang; Armstrong, Tess; Sheng, Ke [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Staton, Robert J.; Pukala, Jason [Department of Radiation Oncology, UF Health Cancer Center - Orlando Health, Orlando, Florida (United States); Pham, Andrew; Low, Daniel A.; Lee, Steve P. [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States); Steinberg, Michael; Manon, Rafael [Department of Radiation Oncology, UF Health Cancer Center - Orlando Health, Orlando, Florida (United States); Chen, Allen M.; Kupelian, Patrick [Department of Radiation Oncology, University of California Los Angeles, Los Angeles, California (United States)

    2015-06-01

    Purpose: The purpose of this study was to systematically monitor anatomic variations and their dosimetric consequences during intensity modulated radiation therapy (IMRT) for head and neck (H&N) cancer by using a graphics processing unit (GPU)-based deformable image registration (DIR) framework. Methods and Materials: Eleven IMRT H&N patients undergoing IMRT with daily megavoltage computed tomography (CT) and weekly kilovoltage CT (kVCT) scans were included in this analysis. Pretreatment kVCTs were automatically registered with their corresponding planning CTs through a GPU-based DIR framework. The deformation of each contoured structure in the H&N region was computed to account for nonrigid change in the patient setup. The Jacobian determinant of the planning target volumes and the surrounding critical structures were used to quantify anatomical volume changes. The actual delivered dose was calculated accounting for the organ deformation. The dose distribution uncertainties due to registration errors were estimated using a landmark-based gamma evaluation. Results: Dramatic interfractional anatomic changes were observed. During the treatment course of 6 to 7 weeks, the parotid gland volumes changed up to 34.7%, and the center-of-mass displacement of the 2 parotid glands varied in the range of 0.9 to 8.8 mm. For the primary treatment volume, the cumulative minimum and mean and equivalent uniform doses assessed by the weekly kVCTs were lower than the planned doses by up to 14.9% (P=.14), 2% (P=.39), and 7.3% (P=.05), respectively. The cumulative mean doses were significantly higher than the planned dose for the left parotid (P=.03) and right parotid glands (P=.006). The computation including DIR and dose accumulation was ultrafast (∼45 seconds) with registration accuracy at the subvoxel level. Conclusions: A systematic analysis of anatomic variations in the H&N region and their dosimetric consequences is critical in improving treatment efficacy. Nearly real

  2. Monitoring Dosimetric Impact of Weight Loss With Kilovoltage (KV) Cone Beam CT (CBCT) During Parotid-Sparing IMRT and Concurrent Chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Kean Fatt, E-mail: hokeanfatt@hotmail.com [Academic Radiation Oncology, The Christie NHS Foundation Trust, Manchester (United Kingdom); Marchant, Tom; Moore, Chris; Webster, Gareth; Rowbottom, Carl [North Western Medical Physics, The Christie NHS Foundation Trust, Manchester (United Kingdom); Penington, Hazel [Wade Radiotherapy Research Centre, The Christie NHS Foundation Trust, Manchester (United Kingdom); Lee, Lip; Yap, Beng; Sykes, Andrew; Slevin, Nick [Department of Clinical Oncology, The Christie NHS Foundation Trust, Manchester (United Kingdom)

    2012-03-01

    Purpose: Parotid-sparing head-and-neck intensity-modulated radiotherapy (IMRT) can reduce long-term xerostomia. However, patients frequently experience weight loss and tumor shrinkage during treatment. We evaluate the use of kilovoltage (kV) cone beam computed tomography (CBCT) for dose monitoring and examine if the dosimetric impact of such changes on the parotid and critical neural structures warrants replanning during treatment. Methods and materials: Ten patients with locally advanced oropharyngeal cancer were treated with contralateral parotid-sparing IMRT concurrently with platinum-based chemotherapy. Mean doses of 65 Gy and 54 Gy were delivered to clinical target volume (CTV)1 and CTV2, respectively, in 30 daily fractions. CBCT was prospectively acquired weekly. Each CBCT was coregistered with the planned isocenter. The spinal cord, brainstem, parotids, larynx, and oral cavity were outlined on each CBCT. Dose distributions were recalculated on the CBCT after correcting the gray scale to provide accurate Hounsfield calibration, using the original IMRT plan configuration. Results: Planned contralateral parotid mean doses were not significantly different to those delivered during treatment (p > 0.1). Ipsilateral and contralateral parotids showed a mean reduction in volume of 29.7% and 28.4%, respectively. There was no significant difference between planned and delivered maximum dose to the brainstem (p = 0.6) or spinal cord (p = 0.2), mean dose to larynx (p = 0.5) and oral cavity (p = 0.8). End-of-treatment mean weight loss was 7.5 kg (8.8% of baseline weight). Despite a {>=}10% weight loss in 5 patients, there was no significant dosimetric change affecting the contralateral parotid and neural structures. Conclusions: Although patient weight loss and parotid volume shrinkage was observed, overall, there was no significant excess dose to the organs at risk. No replanning was felt necessary for this patient cohort, but a larger patient sample will be investigated

  3. 2种容积旋转调强技术在乳腺癌改良根治术后放疗剂量学中的应用比较%Dosimetric comparison between two volumetric modulated photon arc therapies for patients with breast cancer mastecomy

    Institute of Scientific and Technical Information of China (English)

    李丹明; 王黎; 孙新臣; 穆庆霞; 裴忠玲

    2014-01-01

    Objective To compare the dosimetry and treatment efficiency between a multi-ple partial volumetric-modulated arcs therapy (MP-VMAT)and double-arc volumetric modulated arc therapy (DA-VMAT)for patients with breast cancer mastecomy.Methods 19 patients with breast cancer treated by mastecomy and requiring postoperative radiotherapy were collected.MP-VMAT and DA-VMAT plans were applied for each patient respectively.Dosimetry parameters for target volume and organ of risks (OARs)were compared.Machine unite and delivery times were compared.Results MP-VMAT plans had a more uniform target dose distribution with average Conformation Index (CI )andHomogeneity Index (HI )of0 .5 6 and 1 .0 6 compared to 1 .0 6 and 1.14 of the DA-VMAT plans(P <0.05).MP-VMAT plans predicted a reduction of 5.53% in V20 of contralateral lung,3.74 Gy in mean dose,6.27% in V5 and 5.53% in V20 of ispleratal lung respectively (P <0.05).MP-VMAT plans predicted a reduction of 10.33% and 7.82% in V5 and V10 of heartrespectively (P <0.05),MP-VMAT plans predicted a reduction of 9.14%, 2.72% and 0.06% inV5,V10 and V15 of contralateral breast respectively (P <0.05)plans. However,MP-VMAT plans improved monitor units 7 4 5 .9 MU and treatment time 3 0 4 .6 s compared with DA-VMAT 524.4 MU and 196.7 s (P <0.05).Conclusion MP-VMAT plans generate more uniformity in the target dose and decreased the dose of most of organs of risk com-pared to the DA-VMAT,But improved monitor units and treatment time.In clinical application, different techniqies are chosen based on the situation of every patient.%目的:探讨双弧容积旋转调强(DA-VMAT)相比多个部分弧形容积旋转调强(MP-VMAT)在乳腺癌改良根治术后放疗中的剂量学特点及治疗效率。方法2012年8月-2013年8月江苏省人民医院放射治疗科收治的乳腺癌改良根治术后患者19例,采用相同剂量学限制条件分别制订 DA-VMAT 及 MP-VMAT 计划,通过其剂量学对比分析评估靶区

  4. Dosimetric comparison of intensity modulated radiotherapy, volumetric-modulated arc therapy and tomotherapy in patients with gastric adenocarcinoma after curative surgery

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Objective:To compare the dosimetric differences between IMRT, VMAT and TOMO planning for gastric cancer patients.Methods: A total of 14 patients with gastric cancer after curative surgery were prospectively enrolled. In each case, IMRT, VMAT and TOMO plans were created (45Gy/25f). Dose distributions and dose–volume histograms for PTV and normal tissue were compared. A paired t test or signed-rank test was applied to compare the averages between techniques.Results:Comparison of the PTV revealed satisfactory coverage by the 95% isodose envelope in three plans. However, significantly higher conformity index (CI) and lower V20 of bone marrow were observed in TOMO plan. Moreover, IMRT and TOMO techniques both showed signiifcant reduced mean dose of the bilateral lungs compared to the VMAT. Not much difference was found in parameters of the kidney, intestine, spine, liver and heart.Conclusion:The IMRT, VMAT and TOMO plans all achieved favorable target coverage and dose sparing of the critical organs in adjuvant radiotherapy for gastric cancer. However, the TOMO technique displayed the best target dose conformity and superior sparing of the bone marrow and lungs.

  5. Intensity-Modulated Proton Therapy Further Reduces Normal Tissue Exposure During Definitive Therapy for Locally Advanced Distal Esophageal Tumors: A Dosimetric Study

    Energy Technology Data Exchange (ETDEWEB)

    Welsh, James, E-mail: jwelsh@mdanderson.org [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Gomez, Daniel; Palmer, Matthew B.; Riley, Beverly A.; Mayankkumar, Amin V.; Komaki, Ritsuko [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Dong, Lei; Zhu, X. Ronald [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Likhacheva, Anna; Liao, Zhongxing [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Hofstetter, Wayne L. [Department of Thoracic and Cardiovascular Surgery, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Ajani, Jaffer A. [Department of Gastrointestinal Medical Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Cox, James D. [Department of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, Houston, TX (United States)

    2011-12-01

    Purpose: We have previously found that {<=} 75% of treatment failures after chemoradiotherapy for unresectable esophageal cancer appear within the gross tumor volume and that intensity-modulated (photon) radiotherapy (IMRT) might allow dose escalation to the tumor without increasing normal tissue toxicity. Proton therapy might allow additional dose escalation, with even lower normal tissue toxicity. In the present study, we compared the dosimetric parameters for photon IMRT with that for intensity-modulated proton therapy (IMPT) for unresectable, locally advanced, distal esophageal cancer. Patients and Methods: Four plans were created for each of 10 patients. IMPT was delivered using anteroposterior (AP)/posteroanterior beams, left posterior oblique/right posterior oblique (LPO/RPO) beams, or AP/LPO/RPO beams. IMRT was delivered with a concomitant boost to the gross tumor volume. The dose was 65.8 Gy to the gross tumor volume and 50.4 Gy to the planning target volume in 28 fractions. Results: Relative to IMRT, the IMPT (AP/posteroanterior) plan led to considerable reductions in the mean lung dose (3.18 vs. 8.27 Gy, p < .0001) and the percentage of lung volume receiving 5, 10, and 20 Gy (p {<=} .0006) but did not reduce the cardiac dose. The IMPT LPO/RPO plan also reduced the mean lung dose (4.9 Gy vs. 8.2 Gy, p < .001), the heart dose (mean cardiac dose and percentage of the cardiac volume receiving 10, 20, and 30 Gy, p {<=} .02), and the liver dose (mean hepatic dose 5 Gy vs. 14.9 Gy, p < .0001). The IMPT AP/LPO/RPO plan led to considerable reductions in the dose to the lung (p {<=} .005), heart (p {<=} .003), and liver (p {<=} .04). Conclusions: Compared with IMRT, IMPT for distal esophageal cancer lowered the dose to the heart, lung, and liver. The AP/LPO/RPO beam arrangement was optimal for sparing all three organs. The dosimetric benefits of protons will need to be tailored to each patient according to their specific cardiac and pulmonary risks. IMPT for

  6. Validation of dosimetric field matching accuracy from proton therapy using a robotic patient positioning system.

    Science.gov (United States)

    Farr, Jonathan B; O'Ryan-Blair, Avril; Jesseph, Frederick; Hsi, Wen-Chien; Allgower, Chris E; Mascia, Anthony E; Thornton, Allan F; Schreuder, Andreas N

    2010-04-12

    Large area, shallow fields are well suited to proton therapy. However, due to beam production limitations, such volumes typically require multiple matched fields. This is problematic due to the relatively narrow beam penumbra at shallow depths compared to electron and photon beams. Therefore, highly accurate dose planning and delivery is required. As the dose delivery includes shifting the patient for matched fields, accuracy at the 1-2 millimeter level in patient positioning is also required. This study investigates the dosimetric accuracy of such proton field matching by an innovative robotic patient positioner system (RPPS). The dosimetric comparisons were made between treatment planning system calculations, radiographic film and ionization chamber measurements. The results indicated good agreement amongst the methods and suggest that proton field matching by a RPPS is accurate and efficient.

  7. Blood compounds irradiation process: assessment of absorbed dose using Fricke and Thermoluminescent dosimetric systems

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Gabriela de Amorim; Squair, Peterson Lima; Pinto, Fausto Carvalho; Belo, Luiz Claudio Meira; Grossi, Pablo Andrade [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN/MG), Belo Horizonte, MG (Brazil)], e-mail: gas@cdtn.br, e-mail: pls@cdtn.br, e-mail: fcp@cdtn.br, e-mail: lcmb@cdtn.br, e-mail: pabloag@cdtn.br

    2009-07-01

    The assessment of gamma absorbed doses in irradiation facilities allows the quality assurance and control of the irradiation process. The liability of dose measurements is assign to the metrological procedures adopted including the uncertainty evaluation. Fricke and TLD 800 dosimetric systems were used to measure absorbed dose in the blood compounds using the methodology presented in this paper. The measured absorbed doses were used for evaluating the effectiveness of the irradiation procedure and the gamma dose absorption inside the irradiation room of a gamma irradiation facility. The radiation eliminates the functional and proliferative capacities of donor T-lymphocytes, preventing Transfusion associated graft-versus-host disease (TA-GVHD), a possible complication of blood transfusions. The results show the applicability of such dosimetric systems in quality assurance programs, assessment of absorbed doses in blood compounds and dose uniformity assign to the blood compounds irradiation process by dose measurements in a range between 25 Gy and 100 Gy. (author)

  8. Dosimetric systems developed in Brazil for the radiation processes quality control

    Energy Technology Data Exchange (ETDEWEB)

    Galante, Ana Maria Sisti; Campos, Leticia Lucente, E-mail: sgalante@ipen.b, E-mail: lcrodri@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    In order to apply new technologies to the industrial processing of materials aiming economy, efficiency, speed and high quality, ionizing radiation has been used in medicine, archaeology, chemistry, food preservation and other areas. For this reason, the dosimetry area looks for improve current dosimeters and develop new materials for application on quality control of these processes. In Brazil, the research in the dosimetry area occurs with great speed providing many different dosimetric systems. The chemical dosimetry is the most used technique in routine dosimetry, which requires fast and accurate responses. This technique involves determination of absorbed dose by measuring chemical changes radiation induced in the materials. Different dosimetric systems were developed at IPEN for application on radiation process quality and all of them present excellent results; the low cost of these materials allows a more effective dose control, therefore, a larger area or volume can be monitored. (author).

  9. Dosimetric characterisation of Brazilian natural stones using the thermally stimulated exoelectron emission technique

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, F.D.G.; Cecatti, S.G.P.; Caldas, L.V.E

    2002-07-01

    A thermally stimulated exoelectron emission (TSEE) measuring system developed and constructed at IPEN was used to verify the feasibility of the use of Brazilian natural semi-precious stones, such as jasper, amethyst, agate (blue and rose) and quartz (rose and white) for gamma and X radiation detection. Its counting system consists of a 2p windowless gas-flow proportional counter, and the heating system is formed by a temperature programmer that provides linear heating of the samples. The samples were tested in gamma and in X radiation beams and evaluated in relation to their main dosimetric characteristics, as TSEE glow curves, calibration curves and energy dependence. The TSEE results are compared with those of thermoluminescence. The results obtained show the usefulness of Brazilian natural stones as dosimetric materials, using the thermoluminescence and thermally stimulated exoelectron emission techniques. (author)

  10. Panitumumab as a radiosensitizing agent in KRAS wild-type locally advanced rectal cancer.

    Science.gov (United States)

    Mardjuadi, Feby Ingriani; Carrasco, Javier; Coche, Jean-Charles; Sempoux, Christine; Jouret-Mourin, Anne; Scalliet, Pierre; Goeminne, Jean-Charles; Daisne, Jean-François; Delaunoit, Thierry; Vuylsteke, Peter; Humblet, Yves; Meert, Nicolas; van den Eynde, Marc; Moxhon, Anne; Haustermans, Karin; Canon, Jean-Luc; Machiels, Jean-Pascal

    2015-09-01

    Our goal was to optimize the radiosensitizing potential of anti-epidermal growth factor receptor (EGFR) monoclonal antibodies, when given concomitantly with preoperative radiotherapy in KRAS wild-type locally advanced rectal cancer (LARC). Based on pre-clinical studies conducted by our group, we designed a phase II trial in which panitumumab (6 mg/kg/q2 weeks) was combined with preoperative radiotherapy (45 Gy in 25 fractions) to treat cT3-4/N + KRAS wild-type LARC. The primary endpoint was complete pathologic response (pCR) (H0 = 5%, H1 = 17%, α = 0.05, β = 0.2). From 19 enrolled patients, 17 (89%) were evaluable for pathology assessment. Although no pCR was observed, seven patients (41%) had grade 3 Dworak pathological tumor regression. The regimen was safe and was associated with 95% of sphincter-preservation rate. No NRAS, BRAF, or PI3KCA mutation was found in this study, but one patient (5%) showed loss of PTEN expression. The quantification of plasma EGFR ligands during treatment showed significant upregulation of plasma TGF-α and EGF following panitumumab administration (p < 0.05). At surgery, patients with important pathological regression (grade 3 Dworak) had higher plasma TGF-α (p = 0.03) but lower plasma EGF (p = 0.003) compared to those with grade 0-2 Dworak. Our study suggests that concomitant panitumumab and preoperative radiotherapy in KRAS wild-type LARC is feasible and results in some tumor regression. However, pCR rate remained modest. Given that the primary endpoint of our study was not reached, we remain unable to recommend the use of panitumumab as a radiosensitizer in KRAS wild-type LARC outside a research setting.

  11. Dosimetric treatment course simulation based on a statistical model of deformable organ motion.

    Science.gov (United States)

    Söhn, M; Sobotta, B; Alber, M

    2012-06-21

    We present a method of modeling dosimetric consequences of organ deformation and correlated motion of adjacent organ structures in radiotherapy. Based on a few organ geometry samples and the respective deformation fields as determined by deformable registration, principal component analysis (PCA) is used to create a low-dimensional parametric statistical organ deformation model (Söhn et al 2005 Phys. Med. Biol. 50 5893-908). PCA determines the most important geometric variability in terms of eigenmodes, which represent 3D vector fields of correlated organ deformations around the mean geometry. Weighted sums of a few dominating eigenmodes can be used to simulate synthetic geometries, which are statistically meaningful inter- and extrapolations of the input geometries, and predict their probability of occurrence. We present the use of PCA as a versatile treatment simulation tool, which allows comprehensive dosimetric assessment of the detrimental effects that deformable geometric uncertainties can have on a planned dose distribution. For this, a set of random synthetic geometries is generated by a PCA model for each simulated treatment course, and the dose of a given treatment plan is accumulated in the moving tissue elements via dose warping. This enables the calculation of average voxel doses, local dose variability, dose-volume histogram uncertainties, marginal as well as joint probability distributions of organ equivalent uniform doses and thus of TCP and NTCP, and other dosimetric and biologic endpoints. The method is applied to the example of deformable motion of prostate/bladder/rectum in prostate IMRT. Applications include dosimetric assessment of the adequacy of margin recipes, adaptation schemes, etc, as well as prospective 'virtual' evaluation of the possible benefits of new radiotherapy schemes.

  12. Verification criteria on the reliability of personal dosimetric services from x and gamma radiations

    CERN Document Server

    Borasi, G; Kaftal, S

    1990-01-01

    The paper presents the methods used by Working Group ENEA-EDP (Experts in Personal Dosimetry) to control the reliability of the Dosimetric Services operating in Italy and asking for the above controls on voluntary basis. Testing and irradiation test methods are explained as well as the evaluation criteria. The paper includes suggestions and guide-lines to gain the status of 'Reliable Service'. Technical equipment and operating procedures needed to pass the test are also illustrated.

  13. SU-E-T-651: Quantification of Dosimetric Accuracy of Respiratory Gated Stereotactic Body Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Thiyagarajan, Rajesh; Vikraman, S; Maragathaveni, S; Dhivya, N; Kataria, Tejinder [Medanta The Medicity, Gurgaon, Haryana (India); Nambiraj, N Arunai; Sigamani, Ashokkumar [VIT University, Vellore, Tamil Nadu (India); Sinha, Sujit Nath [Nayati Healathcare and Research Pvt Ltd, Mathura, Uttar pradesh (India); Yadav, Girigesh; Raman, Kothanda [Rajiv Gandhi Cancer Institute & Research Centre, Gurgaon, Haryana (India)

    2015-06-15

    Purpose: To quantify the dosimetric accuracy of respiratory gated stereotactic body radiation therapy delivery using dynamic thorax phantom. Methods: Three patients with mobile target (2 lung, 1liver) were chosen. Retrospective 4DCT image sets were acquired for using Varian RPM system. An in-house MATLAB program was designed for MIP, MinIP and AvgIP generation. ITV was contoured on MIP image set for lung patients and on MinIP for liver patient. Dynamic IMRT plans were generated on selected phase bin image set in Eclipse (v10.0) planning system. CIRS dynamic thorax phantom was used to perform the dosimetric quality assurance. Patient breathing pattern file from RPM system was converted to phantom compatible file by an in-house MATLAB program. This respiratory pattern fed to the CIRS dynamic thorax phantom. 4DCT image set was acquired for this phantom using patient breathing pattern. Verification plans were generated using patient gating window and delivered on the phantom. Measurements were carried out using with ion chamber and EBT2 film. Exposed films were analyzed and evaluated in FilmQA software. Results: The stability of gated output in comparison with un-gated output was within 0.5%. The Ion chamber measured and TPS calculated dose compared for all the patients. The difference observed was 0.45%, −0.52% and −0.54 for Patient 1, Patient2 and Patient 3 respectively.Gamma value evaluated from EBT film shows pass rates from 92.41% to 99.93% for 3% dose difference and 3mm distance to agreement criteria. Conclusion: Dosimetric accuracy of respiratory gated SBRT delivery for lung and liver was dosimetrically acceptable. The Ion chamber measured dose was within 0.203±0.5659% of the expected dose. Gamma pass rates were within 96.63±3.84% of the expected dose.

  14. Amorphous chalcogenide semiconductors for solid state dosimetric systems of high-energetic ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Shpotyuk, O. [Pedagogical University, Czestochowa (Poland)]|[Institute of Materials, Lvov (Ukraine)

    1997-12-31

    The application possibilities of amorphous chalcogenide semiconductors use as radiation-sensitive elements of high-energetic (E > 1 MeV) dosimetric systems are analysed. It is shown that investigated materials are characterized by more wide region of registered absorbed doses and low temperature threshold of radiation information bleaching in comparison with well-known analogies based on coloring oxide glasses. (author). 16 refs, 1 tab.

  15. X-Ray Attenuation and Absorption for Materials of Dosimetric Interest

    Science.gov (United States)

    SRD 126 X-Ray Attenuation and Absorption for Materials of Dosimetric Interest (Web, free access)   Tables and graphs of the photon mass attenuation coefficient and the mass energy-absorption coefficient are presented for all of the elements Z = 1 to 92, and for 48 compounds and mixtures of radiological interest. The tables cover energies of the photon (x-ray, gamma ray, bremsstrahlung) from 1 keV to 20 MeV.

  16. Dosimetric impact of orthopedic metal artifact reduction (O-MAR) on spine SBRT patients.

    Science.gov (United States)

    Shen, Zhilei Liu; Xia, Ping; Klahr, Paul; Djemil, Toufik

    2015-09-01

    The dosimetric impact of orthopedic metal artifact reduction (O-MAR) on spine SBRT patients has not been comprehensively studied, particularly with spinal prostheses in high-dose gradient regions. Using both phantom and patient datasets, we investigated dosimetric effects of O-MAR in combination of various metal locations and dose calculation algorithms. A physical phantom, with and without a titanium insert, was scanned. A clinical patient plan was applied to the artifact-free reference, non-O-MAR, and O-MAR phantom images with the titanium located either inside or outside of the tumor. Subsequently, five clinical patient plans were calculated with pencil beam and Monte Carlo (iPlan) on non-O-MAR and O-MAR patient images using an extended CT-density table. The dose differences for phantom plans and patient plans were analyzed using dose distributions, dose-volume histograms (DVHs), gamma index, and selected dosimetric endpoints. From both phantom plans and patient plans, O-MAR did not affect dose distributions and DVHs while minimizing metal artifacts. Among patient plans, we found that, when the same dose calculation method was used, the difference in the dosimetric endpoints between non-O-MAR and O-MAR datasets were small. In conclusion, for spine SBRT patients with spinal prostheses, O-MAR image reconstruction does not affect dose calculation accuracy while minimizing metal artifacts. Therefore, O-MAR images can be safely used for clinical spine SBRT treatment planning. PACS numbers: 87.53.Bn, 87.55.K-, 87.57.Q-, 87.57.cp.

  17. SU-E-T-300: Dosimetric Comparision of 4D Radiation Therapy and 3D Radiation Therapy for the Liver Tumor Based On 4D Medical Image

    Energy Technology Data Exchange (ETDEWEB)

    Ma, C; Yin, Y [Shandong Tumor Hospital, Jinan, Shandong Provice (China)

    2015-06-15

    Purpose: The purpose of this work was to determine the dosimetric benefit to normal tissues by tracking liver tumor dose in four dimensional radiation therapy (4DRT) on ten phases of four dimensional computer tomagraphy(4DCT) images. Methods: Target tracking each phase with the beam aperture for ten liver cancer patients were converted to cumulative plan and compared to the 3D plan with a merged target volume based on 4DCT image in radiation treatment planning system (TPS). The change in normal tissue dose was evaluated in the plan by using the parameters V5, V10, V15, V20,V25, V30, V35 and V40 (volumes receiving 5, 10, 15, 20, 25, 30, 35 and 40Gy, respectively) in the dose-volume histogram for the liver; mean dose for the following structures: liver, left kidney and right kidney; and maximum dose for the following structures: bowel, duodenum, esophagus, stomach and heart. Results: There was significant difference between 4D PTV(average 115.71cm3 )and ITV(169.86 cm3). When the planning objective is 95% volume of PTV covered by the prescription dose, the mean dose for the liver, left kidney and right kidney have an average decrease 23.13%, 49.51%, and 54.38%, respectively. The maximum dose for bowel, duodenum,esophagus, stomach and heart have an average decrease 16.77%, 28.07%, 24.28%, 4.89%, and 4.45%, respectively. Compared to 3D RT, radiation volume for the liver V5, V10, V15, V20, V25, V30, V35 and V40 by using the 4D plans have a significant decrease(P≤0.05). Conclusion: The 4D plan method creates plans that permit better sparing of the normal structures than the commonly used ITV method, which delivers the same dosimetric effects to the target.

  18. SU-E-T-424: Dosimetric Verification of Modulated Electron Radiation Therapy Delivered Using An Electron Specific Multileaf Collimator for Treatment of Scalp Cases

    Energy Technology Data Exchange (ETDEWEB)

    Eldib, A [Fox Chase Cancer Center, Philadelphia, PA (United States); Al-Azhar University Cairo (Egypt); Jin, L; Martin, J; Li, J; Chibani, O; Galloway, T; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States); Mora, G [Universidade de Lisboa, Codex, Lisboa (Portugal)

    2014-06-01

    Purpose: Modulated electron radiotherapy (MERT) has the potential to achieve better treatment outcome for shallow tumors such as those of breast and scalp. In a separate study with scalp lesions, MERT was compared to volumetric modulated arc therapy. Our results showed a reduction in the dose reaching the brain with MERT. However dose calculation accuracy and delivery efficiency challenges remain. Thus in the current study we proceed to add more cases to demonstrate MERT beneficial outcome and its delivery accuracy using an electron specific multileaf collimator (eMLC). Methods: We have used the MCBEAM code for treatment head simulation and for generating phase space files to be used as radiation source input for our Monte Carlo based treatment planning system (MC TPS). MCPLAN code is used for calculation of patient specific dose deposition coefficient and for final MERT plan dose calculation. An in-house developed optimization code is used for the optimization process. MERT plans were generated for real patients and head and neck phantom. Film was used for dosimetric verification. The film was cut following the contour of the curved phantom surface and then sealed with black masking tape. In the measurement, the sealed film packet was sandwiched between two adjacent slabs of the head and neck phantom. The measured 2D dose distribution was then compared with calculations. Results: The eMLC allows effective treatment of scalps with multi-lesions spreading around the patient head, which was usually difficult to plan or very time consuming with conventional applicators. MERT continues to show better reduction in the brain dose. The dosimetric measurements showed slight discrepancy, which was attributed to the film setup. Conclusion: MERT can improve treatment plan quality for patients with scalp cancers. Our in-house MC TPS is capable of performing treatment planning and accurate dose calculation for MERT using the eMLC.

  19. SU-E-J-58: Dosimetric Verification of Metal Artifact Effects: Comparison of Dose Distributions Affected by Patient Teeth and Implants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, M; Kang, S; Lee, S; Suh, T [Department of Biomedical Engineering, College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of); Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea (Korea, Republic of); Lee, J [Konkuk University Medical Center, Seoul (Korea, Republic of); Research Institute of Health Science, Korea University, Seoul (Korea, Republic of); Park, J [Research Institute of Biomedical Engineering, College of Medicine, The Catholic University of Korea (Korea, Republic of); Dept. of Pediatrics and Molecular Imaging Program at Stanford, Stanford University, Stanford (United States); Park, H [Department of Radiation Oncology, Ajou University School of Medicine, Suwon (Korea, Republic of); Lee, B [Research Institute of Health Science, Korea University, Seoul (Korea, Republic of); Daejeon Sun Hospital, Daejeon (Korea, Republic of)

    2014-06-01

    Purpose: Implant-supported dentures seem particularly appropriate for the predicament of becoming edentulous and cancer patients are no exceptions. As the number of people having dental implants increased in different ages, critical dosimetric verification of metal artifact effects are required for the more accurate head and neck radiation therapy. The purpose of this study is to verify the theoretical analysis of the metal(streak and dark) artifact, and to evaluate dosimetric effect which cause by dental implants in CT images of patients with the patient teeth and implants inserted humanoid phantom. Methods: The phantom comprises cylinder which is shaped to simulate the anatomical structures of a human head and neck. Through applying various clinical cases, made phantom which is closely allied to human. Developed phantom can verify two classes: (i)closed mouth (ii)opened mouth. RapidArc plans of 4 cases were created in the Eclipse planning system. Total dose of 2000 cGy in 10 fractions is prescribed to the whole planning target volume (PTV) using 6MV photon beams. Acuros XB (AXB) advanced dose calculation algorithm, Analytical Anisotropic Algorithm (AAA) and progressive resolution optimizer were used in dose optimization and calculation. Results: In closed and opened mouth phantom, because dark artifacts formed extensively around the metal implants, dose variation was relatively higher than that of streak artifacts. As the PTV was delineated on the dark regions or large streak artifact regions, maximum 7.8% dose error and average 3.2% difference was observed. The averaged minimum dose to the PTV predicted by AAA was about 5.6% higher and OARs doses are also 5.2% higher compared to AXB. Conclusion: The results of this study showed that AXB dose calculation involving high-density materials is more accurate than AAA calculation, and AXB was superior to AAA in dose predictions beyond dark artifact/air cavity portion when compared against the measurements.

  20. SU-E-T-176: Clinical Experience of Brass Mesh Bolus: Patient-Specific Parameters as Predictors of Measured Dosimetric Effect

    Energy Technology Data Exchange (ETDEWEB)

    Yock, A; Manger, R; Einck, J; Yashar, C; Sanghvi, P; Hattangadi-Gluth, J; Cervino, L [University of California - San Diego, La Jolla, CA (United States)

    2015-06-15

    Purpose: Increasingly, brass mesh bolus is used to insure dosimetric coverage of the skin for patients treated post-mastectomy for breast cancer. Contribution of photoelectrons from interactions between the bolus and the primary beam increases dose superficially without affecting dose at greater depths. We present our experience using brass mesh bolus – including patients for whom the bolus was dosimetrically inadequate – along with analysis of relevant patient-specific parameters. Methods: Optically-stimulated luminescent dosimeters (OSLDs) were used to determine the effect of the bolus for 15 patients. They were positioned beneath the bolus within the tangent fields at three positions: 1.5–3cm inside the medial and lateral field edges, and midway between the two. All OSLDs were midfield in the cranial-caudal direction. The measurements were compared with patient-specific parameters including separation, chest wall/breast tissue thickness, beam angle incidence, and planned surface dose. Results: The average OSLD measurement at the medial field edge, midfield, and lateral field edge position was 86.8%, 101.8%, and 92.8% of the prescription dose, respectively. A measurement for one patient was low enough (77.0%) to warrant a switch to an alternative type of bolus. Anatomic parameters were analyzed to investigate the low dose in this case, not observed in the planning system. The patient was observed to have a thin chest wall and very oblique beam angles. A second patient was also switched to an alternative type of bolus due to her being high risk and treated with an electron patch that extended onto the breast. Conclusion: Brass mesh bolus increases dose superficially while leaving dose at greater depths unaffected. However, our results suggest that this effect may be insufficient in patients with a thin chest wall or very oblique beam angles. More data and analysis is necessary to proactively identify patients for whom brass mesh bolus is effective.

  1. Sismotectonique et déformation actuelle de la terminaison nord-occidentale de l'arc égéen (Iles ioniennes, Acarnanie, Epire, Grèce)

    OpenAIRE

    Amorese, Daniel

    1993-01-01

    La sismicité de la terminaison Nord-Ouest de l'Arc égéen est analysée à partir de données microsismiques. Celles-ci ont été recueillies par 52 stations qui ont fonctionné, en été 1989, sur les îles Ioniennes, en Acarnanie et en Epire. 656 microséismes ont été localisés et 128 solutions focales construites. La région étudiée constitue la zone de transition entre subduction océanique égéenne (au Sud de Céphalonie) et subduction continentale adriatique (au Nord de Zante). L'activité microsismiqu...

  2. Dosimetric parameters of palladium-103 brachytherapy source with Monte Carlo simulation

    Institute of Scientific and Technical Information of China (English)

    WANG JianHua; LIU Wei; XU XunJiang; GU JiaHui; CAI Jun; HUA ZhengDong; XU JiaQiang

    2008-01-01

    Before clinical application of a new source, the dosimetric parameters of the source should be accu-rately determined. This work is dedicated to the Monte Carlo method to calculate dosimetric parameters as recommended by the American Association of Physicists in Medicine (AAPM) TG-43 guidelines for model ADVANTAGETM palladium-103 source and, through comparison with data from another published report for the same source, presents a suggested dataset for clinical applications. From these calcula-tions, tables are presented for the radial dose function and the anisotropy function of palladium-103 brachytherapy source. The dose rate constants are found to be 0.671 (cGyh-1U-1) in liquid water and 0.673 (cGyh-1U-1) in Solid WaterTM. And the anisotropy constants in liquid water and Solid WaterTM are found to be 0.864 and 0.865 respectively. Comparison with the previous study shows that our results of dosimetric parameters are in good agreement with those measured and calculated by Meigooni et al. (2006) both in Water and Solid WaterTM.

  3. Dosimetric characteristics of novalis Tx system with high definition multileaf collimator.

    Science.gov (United States)

    Chang, Zheng; Wang, Zhiheng; Wu, Q Jackie; Yan, Hui; Bowsher, Jim; Zhang, Junan; Yin, Fang-Fang

    2008-10-01

    A new Novalis Tx system equipped with a high definition multileaf collimator (HDMLC) recently became available to perform both image-guided radiosurgery and conventional radiotherapy. It is capable of delivering a highly conformal radiation dose with three energy modes: 6 MV photon energy, 15 MV photon energy, and 6 MV photon energy in a stereotactic radiosurgery mode with 1000 MU/min dose rate. Dosimetric characteristics of the new Novalis Tx treatment unit with the HDMLC are systematically measured for commissioning. A high resolution diode detector and miniion-chamber detector are used to measure dosimetric data for a range of field sizes from 4 x 4 mm to 400 x 400 mm. The commissioned Novalis Tx system has passed the RPC stereotactic radiosurgery head phantom irradiation test. The Novalis Tx system not only expands its capabilities with three energy modes, but also achieves better beam conformity and sharer beam penumbra with HDMLC. Since there is little beam data information available for the new Novalis Tx system, we present in this work the dosimetric data of the new modality for reference and comparison.

  4. Dosimetric characteristics of Novalis Tx system with high definition multileaf collimator

    Energy Technology Data Exchange (ETDEWEB)

    Chang Zheng; Wang Zhiheng; Wu, Q. Jackie; Yan Hui; Bowsher, Jim; Zhang Junan; Yin Fangfang [Department of Radiation Oncology, Duke University, Box 3295, Duke University Medical Center, Durham, North Carolina 27710 (United States)

    2008-10-15

    A new Novalis Tx system equipped with a high definition multileaf collimator (HDMLC) recently became available to perform both image-guided radiosurgery and conventional radiotherapy. It is capable of delivering a highly conformal radiation dose with three energy modes: 6 MV photon energy, 15 MV photon energy, and 6 MV photon energy in a stereotactic radiosurgery mode with 1000 MU/min dose rate. Dosimetric characteristics of the new Novalis Tx treatment unit with the HDMLC are systematically measured for commissioning. A high resolution diode detector and miniion-chamber detector are used to measure dosimetric data for a range of field sizes from 4x4 mm to 400x400 mm. The commissioned Novalis Tx system has passed the RPC stereotactic radiosurgery head phantom irradiation test. The Novalis Tx system not only expands its capabilities with three energy modes, but also achieves better beam conformity and sharer beam penumbra with HDMLC. Since there is little beam data information available for the new Novalis Tx system, we present in this work the dosimetric data of the new modality for reference and comparison.

  5. Dosimetric characterization of a bi-directional micromultileaf collimator for stereotactic applications.

    Science.gov (United States)

    Bucciolini, M; Russo, S; Banci Buonamici, F; Pini, S; Silli, P

    2002-07-01

    A 6 MV photon beam from Linac SL75-5 has been collimated with a new micromultileaf device that is able to shape the field in the two orthogonal directions with four banks of leaves. This is the first clinical installation of the collimator and in this paper the dosimetric characterization of the system is reported. The dosimetric parameters required by the treatment planning system used for the dose calculation in the patient are: tissue maximum ratios, output factors, transmission and leakage of the leaves, penumbra values. Ionization chambers, silicon diode, radiographic films, and LiF thermoluminescent dosimeters have been employed for measurements of absolute dose and beam dosimetric data. Measurements with different dosimeters supply results in reasonable agreement among them and consistent with data available in literature for other models of micromultileaf collimator; that permits the use of the measured parameters for clinical applications. The discrepancies between results obtained with the different detectors (around 2%) for the analyzed parameters can be considered an indication of the accuracy that can be reached by current stereotactic dosimetry.

  6. Dosimetric property of mineral extracted from calamari and exposed to gamma rays

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Zaragoza, E.; Roman-Lopez, J.; Cruz, L. Perez; Furetta, C. [Unidad de Irradiacion y Seguridad Radiologica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F (Mexico); Chiaravalle, E.; Mangiacotti, M.; Marchesani, G. [Centro di Referenza Nazionale per la Ricerca della Radioattivita nel Settore Zootecnico-Veterinario, Istituto Zooprofilattico Sperimentale della Puglia e della Basilicata, Via Manfredonia 20, I-71121 Foggia (Italy)

    2013-07-03

    Dosimetric property of polymineral fraction, quartz mainly, obtained from calamari was investigated. The commercial calamari samples from China and Sud Africa were collected in the markets of Italy. All polymineral debris were extracted and isolated from the whole body of calamari. The surface of the polymineral samples was analyzed by using the Scanning Electron Microscopy (SEM) and their chemical composition was determined using Energy Dispersive Spectroscopy (EDS). The polymineral was exposed to gamma rays ({sup 60}Co) at different doses (0.5-80 Gy) to determine dosimetric property. Thermoluminescent (TL) glow curves showed two peaks centered at around 98-100 Degree-Sign C and 128-138 Degree-Sign C temperature range. The glow curves have been analyzed by using a deconvolution program. A linear dose response between 0.5 to 20 Gy was observed. The TL response of the samples as a function of the time storage, fading, presented a reduction of about 36-40 % at the end of 24 h. The reproducibility of the TL response after ten cycles of irradiation-readout showed an acceptable standard deviation in dosimetry. The polimineral fraction obtained from calamari shows an interesting dosimetric property and it may be useful for dosimetry in gamma radiation field.

  7. Descriptif et qualification d'un mode opératoire de soudage pour les matériaux métalliques - Épreuve de qualification d'un mode opératoire de soudage - Partie 6: Soudage à l'arc et aux gaz du cuivre et de ses alliages

    CERN Document Server

    2006-01-01

    Descriptif et qualification d'un mode opératoire de soudage pour les matériaux métalliques - Épreuve de qualification d'un mode opératoire de soudage - Partie 6: Soudage à l'arc et aux gaz du cuivre et de ses alliages

  8. Dosimetric comparison of four different external beams for breast irradiation

    Science.gov (United States)

    Lee, Yoon Hee; Chung, Weon Kuu; Kim, Dong Wook; Kwon, Oh Young

    2017-02-01

    An intensity-modulated radiation-therapy (IMRT)-based technique, blocked single iso-centric IMRT (IMRT), is compared to multi-center IMRT (MIRT) and other conventional techniques such as three dimensional conformal radiation therapy (3D-CRT) and volumetric modulated arc therapy (VMAT) for the treatment of breast cancer patients. Four different plans were devised and compared for 15 breast cancer patients, all of whom had early stage disease and had undergone breast conserving surgery. A total dose of 50.4 Gy in 28 fractions was prescribed as the planning target volume in all treatment plans. The doses to the ipsilateral lung, heart, and opposite breast were compared using a dose-volume histogram. The conformity index (CI), homogeneity index (HI), and coverage index (CoVI) were evaluated and compared among the four treatment techniques. The lifetime attributable risk (LAR) associated with each of the four techniques from age at exposure of 30 to 100 years was measured for the organs at risk. We found that MIRT had a better CoVI (1.02 ± 0.13 and 1.01 ± 0.04, respectively) and IMRT had a better CI (0.88 ± 0.04, and 0.87 ± 0.02, respectively) compared to the other three modalities. All four techniques had similar HIs. Moreover, we found that IMRT and MIRT were less likely to cause radiation induced-pneumonitis, 3D-CRT had the lowest LAR, IMRT and MIRT had similar LARs and VMAT had the highest LAR. In study we found that compared to the VMAT, MIRT and IMRT provided adequate the planning target volume (PTV) coverage and reduced the risk of secondary cancers in most of the organs at risk (OARs), while 3D-CRT had the lowest secondary-cancer risks. Therefore, 3D-CRT is still a reasonable choice for whole breast RT except for patients with complex PTV shapes, in which cases IMRT and MIRT may provide better target coverage.

  9. Organ Preservation in Rectal Adenocarcinoma: a phase II randomized controlled trial evaluating 3-year disease-free survival in patients with locally advanced rectal cancer treated with chemoradiation plus induction or consolidation chemotherapy, and total mesorectal excision or nonoperative management

    OpenAIRE

    SMITH, J. JOSHUA; Chow, Oliver S; Gollub, Marc J.; Nash, Garrett M.; Temple, Larissa K.; Weiser, Martin R.; Guillem, José G.; Paty, Philip B.; Avila, Karin; Garcia-Aguilar, Julio; ,

    2015-01-01

    Background Treatment of patients with non-metastatic, locally advanced rectal cancer (LARC) includes pre-operative chemoradiation, total mesorectal excision (TME) and post-operative adjuvant chemotherapy. This trimodality treatment provides local tumor control in most patients; but almost one-third ultimately die from distant metastasis. Most survivors experience significant impairment in quality of life (QoL), due primarily to removal of the rectum. A current challenge lies in identifying pa...

  10. Dosimetric comparison of helical tomotherapy and dynamic conformal arc therapy in stereotactic radiosurgery for vestibular schwannomas.

    Science.gov (United States)

    Lee, Tsair-Fwu; Chao, Pei-Ju; Wang, Chang-Yu; Lan, Jen-Hong; Huang, Yu-Je; Hsu, Hsuan-Chih; Sung, Chieh-Cheng; Su, Te-Jen; Lian, Shi-Long; Fang, Fu-Min

    2011-01-01

    The dosimetric results of stereotactic radiosurgery (SRS) for vestibular schwannoma (VS) performed using dynamic conformal arc therapy (DCAT) with the Novalis system and helical TomoTherapy (HT) were compared using plan quality indices. The HT plans were created for 10 consecutive patients with VS previously treated with SRS using the Novalis system. The dosimetric indices used to compare the techniques included the conformity index (CI) and homogeneity index (HI) for the planned target volume (PTV), the comprehensive quality index (CQI) for nine organs at risk (OARs), gradient score index (GSI) for the dose drop-off outside the PTV, and plan quality index (PQI), which was verified using the plan quality discerning power (PQDP) to incorporate 3 plan indices, to evaluate the rival plans. The PTV ranged from 0.27-19.99 cm(3) (median 3.39 cm(3)), with minimum required PTV prescribed doses of 10-16 Gy (median 12 Gy). Both systems satisfied the minimum required PTV prescription doses. HT conformed better to the PTV (CI: 1.51 ± 0.23 vs. 1.94 ± 0.34; p < 0.01), but had a worse drop-off outside the PTV (GSI: 40.3 ± 10.9 vs. 64.9 ± 13.6; p < 0.01) compared with DCAT. No significant difference in PTV homogeneity was observed (HI: 1.08 ± 0.03 vs. 1.09 ± 0.02; p = 0.20). HT had a significantly lower maximum dose in 4 OARs and significant lower mean dose in 1 OAR; by contrast, DCAT had a significantly lower maximum dose in 1 OAR and significant lower mean dose in 2 OARs, with the CQI of the 9 OARs = 0.92 ± 0.45. Plan analysis using PQI (HT 0.37 ± 0.12 vs. DCAT 0.65 ± 0.08; p < 0.01), and verified using the PQDP, confirmed the dosimetric advantage of HT. However, the HT system had a longer beam-on time (33.2 ± 7.4 vs. 4.6 ± 0.9 min; p < 0.01) and consumed more monitor units (16772 ± 3803 vs. 1776 ± 356.3; p < 0.01). HT had a better dose conformity and similar dose homogeneity but worse dose gradient than DCAT. Plan analysis confirmed the dosimetric advantage of HT

  11. TU-D-9A-01: TG176: Dosimetric Effects of Couch Tops and Immobilization Devices

    Energy Technology Data Exchange (ETDEWEB)

    Olch, A [Childrens Hospital of LA, Los Angeles, CA (United States)

    2014-06-15

    The dosimetric impact from devices external to the patient is a complex combination of increased skin dose, reduced tumor dose, and altered dose distribution. Although small monitor unit or dose corrections are routinely made for blocking trays, ion chamber correction factors, or tissue inhomogeneities, the dose perturbation of the treatment couch top or immobilization devices are often overlooked. These devices also increase surface dose, an effect which is also often ignored or underestimated. These concerns have grown recently due to the increased use of monolithic carbon fiber couch tops which are optimal for imaging for patient position verification but cause attenuation and increased surface dose compared to the ‘tennis racket’ style couch top they often replace. Also, arc delivery techniques have replaced stationary gantry techniques which cause a greater fraction of the dose to be delivered from posterior angles. A host of immobilization devices are available and used to increase patient positioning reproducibility, and these also have attenuation and skin dose implications which are often ignored. This report of Task Group 176 serves to present a survey of published data that illustrates the magnitude of the dosimetric effects of a wide range of devices external to the patient. The report also provides methods for modeling couch tops in treatment planning systems so the physicist can accurately compute the dosimetric effects for indexed patient treatments. Both photon and proton beams are considered. A discussion on avoidance of high density structures during beam planning is also provided. An important aspect of this report are the recommendations we make to clinical physicists, treatment planning system vendors, and device vendors on how to make measurements of skin dose and attenuation, how to report these values, and for the vendors, an appeal is made to work together to provide accurate couch top models in planning systems. Learning Objectives

  12. Dosimetric measurements of an n-butyl cyanoacrylate embolization material for arteriovenous malformations

    Energy Technology Data Exchange (ETDEWEB)

    Labby, Zacariah E., E-mail: zelabby@humonc.wisc.edu [Department of Human Oncology, University of Wisconsin–Madison, 600 Highland Avenue, Madison, Wisconsin 53792 (United States); Chaudhary, Neeraj [Division of Neurointerventional Radiology, Departments of Radiology and Neurosurgery, University of Michigan Hospital and Health Systems, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109 (United States); Gemmete, Joseph J. [Division of Neurointerventional Radiology, Departments of Radiology, Neurosurgery, and Otolaryngology, University of Michigan Hospital and Health Systems, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109 (United States); Pandey, Aditya S. [Department of Neurosurgery, University of Michigan Hospital and Health Systems, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109 (United States); Roberts, Donald A. [Radiation Physics Division, Department of Radiation Oncology, University of Michigan Hospital and Health Systems, 1500 East Medical Center Drive, Ann Arbor, Michigan 48109 (United States)

    2015-04-15

    Purpose: The therapeutic regimen for cranial arteriovenous malformations often involves both stereotactic radiosurgery and endovascular embolization. Embolization agents may contain tantalum or other contrast agents to assist the neurointerventionalists, leading to concerns regarding the dosimetric effects of these agents. This study investigated dosimetric properties of n-butyl cyanoacrylate (n-BCA) plus lipiodol with and without tantalum powder. Methods: The embolization agents were provided cured from the manufacturer with and without added tantalum. Attenuation measurements were made for the samples and compared to the attenuation of a solid water substitute using a 6 MV photon beam. Effective linear attenuation coefficients (ELAC) were derived from attenuation measurements made using a portal imager and derived sample thickness maps projected in an identical geometry. Probable dosimetric errors for calculations in which the embolized regions are overridden with the properties of water were calculated using the ELAC values. Interface effects were investigated using a parallel plate ion chamber placed at set distances below fixed samples. Finally, Hounsfield units (HU) were measured using a stereotactic radiosurgery CT protocol, and more appropriate HU values were derived from the ELAC results and the CT scanner’s HU calibration curve. Results: The ELAC was 0.0516 ± 0.0063 cm{sup −1} and 0.0580 ± 0.0091 cm{sup −1} for n-BCA without and with tantalum, respectively, compared to 0.0487 ± 0.0009 cm{sup −1} for the water substitute. Dose calculations with the embolized region set to be water equivalent in the treatment planning system would result in errors of −0.29% and −0.93% per cm thickness of n-BCA without and with tantalum, respectively. Interface effects compared to water were small in magnitude and limited in distance for both embolization materials. CT values at 120 kVp were 2082 and 2358 HU for n-BCA without and with tantalum, respectively

  13. Dosimetric investigations of laser-induced phase transition of MX1-cell membranes by use of quantum dots

    Science.gov (United States)

    Beuthan, J.; Dressler, C.; Minet, O.; Müller, G.

    2006-05-01

    It is well known that laser scattered-light applicators when applied for laser-induced tumor therapy allow the precise thermal destruction of metastases. Using laser radiation in the NIR spectral range (usually, Nd:YAG laser systems λ = 1064 nm), a penetration depth of 5-10 cm (1/ e is the decrease in radiation intensity) is achieved in biological tissues. The major tissue-optical parameters, i.e., absorption coefficient μa, scattering coefficient μs, and the anisotropy factor g, show biological tissues to be strongly scattering media which have a so-called optical window in the NIR. As a consequence, the therapeutic laser radiation is scattered and absorbed at a deeper level, leading to a virtual enlargement of the laser applicator. The thermal sclerotization and the thermal cell damage originate within the absorbing volume of the laser radiation and spread outward by thermal diffusion. There are three dosimetrically relevant zones of thermal and biological damage: (1) a zone of thermal coagulation; (2) a threshold of partial necrosis (destruction of all metabolic processes in the cell is the maintenance of essential parts of the cytoskeleton and the plasma membrane); this is characterized by a specific temperature range, the so-called phase transition, which refers to the transition from the gel phase of the biomembrane to the fluid phase; the determination of this temperature zone is an integral part of the following experimental investigations on MX1 cells; (3) an external zone of thermal effects made up of partial and multiple damage with a statistical chance of survival. This paper describes the investigations on heat stress in cancer cells to verify the maximum phase transition of the outer MX1 cell membranes and the related results. For this purpose, a novel method of quantum dot fluorescence dosimetry was developed. The evaluation of the measured laser-induced fluorescences yields a first approximation of the determination of the phase transition on MX1

  14. Metal artifacts in computed tomography for radiation therapy planning: dosimetric effects and impact of metal artifact reduction

    Science.gov (United States)

    Giantsoudi, Drosoula; De Man, Bruno; Verburg, Joost; Trofimov, Alexei; Jin, Yannan; Wang, Ge; Gjesteby, Lars; Paganetti, Harald

    2017-04-01

    A significant and increasing number of patients receiving radiation therapy present with metal objects close to, or even within, the treatment area, resulting in artifacts in computed tomography (CT) imaging, which is the most commonly used imaging method for treatment planning in radiation therapy. In the presence of metal implants, such as dental fillings in treatment of head-and-neck tumors, spinal stabilization implants in spinal or paraspinal treatment or hip replacements in prostate cancer treatments, the extreme photon absorption by the metal object leads to prominent image artifacts. Although current CT scanners include a series of correction steps for beam hardening, scattered radiation and noisy measurements, when metal implants exist within or close to the treatment area, these corrections do not suffice. CT metal artifacts affect negatively the treatment planning of radiation therapy either by causing difficulties to delineate the target volume or by reducing the dose calculation accuracy. Various metal artifact reduction (MAR) methods have been explored in terms of improvement of organ delineation and dose calculation in radiation therapy treatment planning, depending on the type of radiation treatment and location of the metal implant and treatment site. Including a brief description of the available CT MAR methods that have been applied in radiation therapy, this article attempts to provide a comprehensive review on the dosimetric effect of the presence of CT metal artifacts in treatment planning, as reported in the literature, and the potential improvement suggested by different MAR approaches. The impact of artifacts on the treatment planning and delivery accuracy is discussed in the context of different modalities, such as photon external beam, brachytherapy and particle therapy, as well as by type and location of metal implants.

  15. SU-E-J-274: Responses of Medulloblastoma Cells to Radiation Dosimetric Parameters in Intensity-Modulated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Park, J [Dept. of Pediatrics, Stanford University School of Medicine, Stanford, CA (United States); Molecular Imaging Program at Stanford, Stanford, CA (United States); Bio-X Program, Stanford, CA (United States); Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Park, J [Proton Therapy Center, National Cancer Center, Goyang (Korea, Republic of); Rogalla, S; Contag, C [Dept. of Pediatrics, Stanford University School of Medicine, Stanford, CA (United States); Molecular Imaging Program at Stanford, Stanford, CA (United States); Bio-X Program, Stanford, CA (United States); Woo, D [Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Lee, D [Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Park, H [Dept. of Radiation Oncology, Ajou University School of Medicine, Suwon (Korea, Republic of); Suh, T [Research Institute of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of); Dept. of Biomedical Engineering, The Catholic University of Korea, Seoul (Korea, Republic of)

    2015-06-15

    Purpose: To evaluate radiation responses of the medulloblastoma cell line Daoy in intensity-modulated radiation therapy (IMRT), quantitative variations to variable radiation dosimetic parameters were tracked by bioluminescent images (BLIs). Methods: The luciferase and green fluorescent protein positive Daoy cells were cultured on dishes. The medulloblastoma cells irradiated to different dose rate, interval of fractionated doses, field margin and misalignment, and dose uniformity in IMRT were monitored using bioluminescent images. The cultured cells were placed into a dedicated acrylic phantom to deliver intensity-modulated fluences and calculate accurate predicted dose distribution. The radiation with dose rate from 0.5 Gy/min to 15 Gy/min was irradiated by adjusting monitor unit per minute and source-to-surface distances. The intervals of fractionated dose delivery were changed considering the repair time of double strand breaks (DSB) revealed by straining of gamma-H2AX.The effect of non-uniform doses on the cells were visualized by registering dose distributions and BLIs. The viability according to dosimetric parameters was correlated with bioluminescent intensities for cross-check of radiation responses. Results: The DSB and cell responses due to the first fractionated dose delivery significantly affected final tumor control rather than other parameters. The missing tumor volumes due to the smaller field margin than the tumor periphery or field misalignment caused relapse of cell responses on BLIs. The dose rate and gradient had effect on initial responses but could not bring out the distinguishable killing effect on cancer cells. Conclusion: Visualized and quantified bioluminescent images were useful to correlate the dose distributions with spatial radiation effects on cells. This would derive the effective combination of dose delivery parameters and fractionation. Radiation responses in particular IMRT configuration could be reflected to image based-dose re-optimization.

  16. Prognostic Impact of mRNA Expression Levels of HER1–4 (ERBB1–4 in Patients with Locally Advanced Rectal Cancer

    Directory of Open Access Journals (Sweden)

    Melanie Kripp

    2016-01-01

    Full Text Available Background. No predictive or prognostic biomarker is available for patients with locally advanced rectal cancer (LARC undergoing perioperative chemoradiotherapy (CRT. Members of the human epidermal growth factor receptor (HER family of receptor tyrosine kinases EGFR (HER1, ERBB1, HER2 (ERBB2, HER3 (ERBB3, and HER4 (ERBB4 are therapeutic targets in several cancers. The analysis was performed to assess expression levels and study the potential prognostic impact for disease-free and overall survival in patients with LARC. Patients and Methods. ERBB1–4 mRNA expression and tumor proliferation using Ki-67 (MKI67 mRNA were evaluated using RT-quantitative PCR in paraffin-embedded tumor samples from 86 patients (median age: 63 treated with capecitabine or 5-fluorouracil-based CRT within a phase 3 clinical trial. Results. A positive correlation of HER4 and HER2, HER3 and HER2, and HER4 and HER3 with each other was observed. Patients with high mRNA expression of ERBB1 (EGFR, HER1 had significantly increased risk for recurrence and death. Patients with high mRNA expression of MKI67 had reduced risk for relapse. Conclusion. This analysis suggests a prognostic impact of both ERBB1 and MKi67 mRNA expression in LARC patients treated with capecitabine or fluorouracil-based chemoradiotherapy.

  17. Quality indicators for breast cancer

    DEFF Research Database (Denmark)

    Poortmans, Philip; Aznar, Marianne; Bartelink, Harry

    2012-01-01

    cancer patients in terms of disease control, survival, and quality of life. This progress is based on clinical research and paralleled by progress in delivering sophisticated radiation treatment. Clinical trials resulted in identifying patients groups who will benefit from radiation treatment. They also...... the treatment. Still, a large source of variation and uncertainty in radiation therapy remains in the definition of target volumes, which is clinically significant in terms of dosimetric target coverage as well as exposure of healthy tissues. This striving for continuous improvement of patient selection...

  18. Comparison of dose accuracy between 2D array detectors and Epid for IMRT of nasopharynx cancer

    Science.gov (United States)

    Altiparmak, Duygu; Coban, Yasin; Merih, Adil; Avci, Gulhan Guler; Yigitoglu, Ibrahim

    2017-02-01

    The aim of this study is to perform the dosimetric controls of nasopharynx cancer patient's intensity modulated radiation therapy (IMRT) treatment plans that generated by treatment planing system (TPS) with using two different equipments and also to make comparison in terms of their reliability and practicability. This study has been performed at Radiation Oncology Department, Medicine Faculty in Gaziosmanpasa University by using the VARIAN CLINAC DHX linear accelerator which is operated in the range of 6 MV. Selected 10 nasopharynx patients planned in TPS (Eclipce V13.0) and approved for treatment by medical physicists and radiation oncologists. These plans recalculated on EPID and mapcheck which are 2D dosimetric equipments to obtain dose maps. To compare these two dosimetric equipments gamma analysis method has been preferred. Achieved data is presented and discussed.

  19. VMAT planning study in rectal cancer patients

    OpenAIRE

    Shang, Jun; Kong, Wei; Wang, Yan-Yang; Ding, Zhe; Yan, Gang; Zhe, Hong

    2014-01-01

    Background To compare the dosimetric differences among fixed field intensity-modulated radiation therapy (IMRT), single-arc volumetric-modulated arc therapy (SA-VMAT) and double-arc volumetric-modulated arc therapy (DA-VMAT) plans in rectal cancer. Method Fifteen patients with rectal cancer previously treated with IMRT in our institution were selected for this study. For each patient, three plans were generated with the planning CT scan: one using a fixed beam IMRT, and two plans using the VM...

  20. Radiation-induced complications in prostate cancer patients treated with radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Azuddin, A. Yusof [School of Applied Physics, Faculty of Sciences and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor, Malaysia and Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 53000 Kuala Lumpur (Malaysia); Rahman, I. Abdul; Mohamed, F. [School of Applied Physics, Faculty of Sciences and Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor (Malaysia); Siah, N. J. [Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 53000 Kuala Lumpur (Malaysia); Saadc, M. [Department of Oncology, University Malaya Medical Center, 50603 Kuala Lumpur (Malaysia); Ismail, F. [Department of Oncology and Radiotherapy, Universiti Kebangsaan Malaysia Medical Centre, 56000 Cheras, Kuala Lumpur (Malaysia)

    2014-09-03

    The purpose of the study is to determine the relationship between radiation-induced complications with dosimetric and radiobiological parameters for prostate cancer patients that underwent the conformal radiotherapy treatment. 17 prostate cancer patients that have been treated with conformal radiotherapy were retrospectively analysed. The dosimetric data was retrieved in the form of dose-volume histogram (DVH) from Radiotherapy Treatment Planning System. The DVH was utilised to derived Normal Tissue Complication Probability (NTCP) in radiobiological data. Follow-up data from medical records were used to grade the occurrence of acute gastrointestinal (GI) and genitourinary (GU) complications using Radiation Therapy Oncology Group (RTOG) scoring system. The chi-square test was used to determine the relationship between radiation-induced complication with dosimetric and radiobiological parameters. 8 (47%) and 7 (41%) patients were having acute GI and GU complications respectively. The acute GI complication can be associated with V60{sub rectum}, rectal mean dose and NTCP{sub rectum} with p-value of 0.016, 0.038 and 0.049 respectively. There are no significant relationships of acute GU complication with dosimetric and radiobiological variables. Further study can be done by increase the sample size and follow up duration for deeper understanding of the factors that effecting the GU and GI complication in prostate cancer radiotherapy.

  1. Deformable image registration for geometrical evaluation of DIBH radiotherapy treatment of lung cancer patients

    DEFF Research Database (Denmark)

    Ottosson, Wiviann; Lykkegaard Andersen, J. A.; Borrisova, S.;

    2014-01-01

    Respiration and anatomical variation during radiotherapy (RT) of lung cancer yield dosimetric uncertainties of the delivered dose, possibly affecting the clinical outcome if not corrected for. Adaptive radiotherapy (ART), based on deformable image registration (DIR) and Deep-Inspiration-Breath-Ho......Respiration and anatomical variation during radiotherapy (RT) of lung cancer yield dosimetric uncertainties of the delivered dose, possibly affecting the clinical outcome if not corrected for. Adaptive radiotherapy (ART), based on deformable image registration (DIR) and Deep...... locally advanced non-small cell lung cancer patients were included, each with a planning-, midterm- and final CT (pCT, mCT, fCT) and 7 CBCTs acquired weekly and on the same day as the mCT and fCT. All imaging were performed in both FB and DIBH, using Varian RPM system for respiratory tracking...... perform better image registration than FB images. However DIR is a feasible tool for ART of lung cancer....

  2. Dosimetric Evaluation of High-Dose-Rate Interstitial Brachytherapy Boost Treatments for Localized Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Froehlich, Georgina [Semmelweis Univ., Budapest (Hungary); Dept. of Radiotherapy, National Inst. of Oncology, Budapest (Hungary); Agoston, Peter; Loevey, Jozsef; Somogyi, Andras; Fodor, Janos; Polgar, Csaba; Major, Tibor [Dept. of Radiotherapy, National Inst. of Oncology, Budapest (Hungary)

    2010-07-15

    Purpose: to quantitatively evaluate the dose distributions of high-dose-rate (HDR) prostate implants regarding target coverage, dose homogeneity, and dose to organs at risk. Material and methods: treatment plans of 174 implants were evaluated using cumulative dose-volume histograms (DVHs). The planning was based on transrectal ultrasound (US) imaging, and the prescribed dose (100%) was 10 Gy. The tolerance doses to rectum and urethra were 80% and 120%, respectively. Dose-volume parameters for target (V90, V100, V150, V200, D90, D{sub min}) and quality indices (DNR [dose nonuniformity ratio], DHI [dose homogeneity index], CI [coverage index], COIN [conformal index]) were calculated. Maximum dose in reference points of rectum (D{sub r}) and urethra (D{sub u}), dose to volume of 2 cm{sup 3} of the rectum (D{sub 2ccm}), and 0.1 cm{sup 3} and 1% of the urethra (D{sub 0.1ccm} and D1) were determined. Nonparametric correlation analysis was performed between these parameters. Results: the median number of needles was 16, the mean prostate volume (V{sub p}) was 27.1 cm{sup 3}. The mean V90, V100, V150, and V200 were 90%, 97%, 39% and 13%, respectively. The mean D90 was 109%, and the D{sub min} was 87%. The mean doses in rectum and urethra reference points were 75% and 119%, respectively. The mean volumetric doses were D{sub 2ccm} = 49% for the rectum, D{sub 0.1ccm} = 126%, and D1 = 140% for the urethra. The mean DNR was 0.37, while the DHI was 0.60. The mean COIN was 0.66. The Spearman rank order correlation coefficients for volume doses to rectum and urethra were R(D{sub r}, D{sub 2ccm}) = 0.69, R(D{sub u}, D{sub 0.1ccm}) = 0.64, R(D{sub u}, D1) = 0.23. Conclusion: US-based treatment plans for HDR prostate implants based on the real positions of catheters provided acceptable dose distributions. In the majority of the cases, the doses to urethra and rectum were kept below the defined tolerance levels. For rectum, the dose in reference points correlated well with dose-volume parameters. For urethra dose characterization, the use of D1 volumetric parameter is recommended. (orig.)

  3. Association of pretreatment serum carcinoembryonic antigen levels with chemoradiation-induced downstaging and downsizing of rectal cancer.

    Science.gov (United States)

    Yeo, Seung-Gu

    2016-04-01

    The aim of this study was to identify pretreatment clinical parameters associated with preoperative chemoradiotherapy (CRT)-induced downstaging and downsizing of locally advanced rectal cancer (LARC T3-4 or N+). Data from 51 LARC patients, who received preoperative CRT and radical surgery between 2010 and 2013, were retrospectively analyzed. Rectal adenocarcinoma was histologically confirmed in all patients, who ranged in age between 41 and 81 years (median, 64 years). CRT consisted of 50.4 Gy pelvic radiotherapy with concurrent chemotherapy using 5-fluorouracil and leucovorin. After a median interval of 7 weeks post-CRT, the patients underwent total mesorectal excision. Downstaging was defined as the transition from cStage II-III to ypStage 0-I. The longest tumor diameter was measured pre- and post-CRT using computed tomography or magnetic resonance imaging, and based on the surgical specimen, respectively. Downstaging was observed in 16 (31.4%) patients, including 5 (9.8%) with a pathological complete response. The median downsizing rate was 60%. The serum carcinoembryonic antigen (CEA) levels were 0.8-153.9 ng/ml (median, 4.4 ng/ml). The maximum standardized uptake value was 4.7-33.9 (median, 10.8). On univariate analysis, cT stage, tumor size and CEA level were associated with downstaging. On multivariate analysis, only CEA level (≤5 ng/ml) was a significant predictor of downstaging (odds ratio = 16.0; 95% confidence interval: 1.8-146.7; P=0.014). CEA level was the only factor significantly associated with downsizing (>60%) in the univariate analysis. These results demonstrated that pretreatment serum CEA levels are significantly associated with downstaging as well as downsizing of LARC following preoperative CRT. Therefore, this parameter may be useful in personalizing the management of LARC patients.

  4. Oxaliplatin and capecitabine concomitant with neoadjuvant radiotherapy and extended to the resting period in high risk locally advanced rectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Y.H.; Zeng, Z.F. [State Key Laboratory of Oncology in South China, Guangzhou (China); Sun Yat-sen University Cancer Center, Departments of Radiation Oncology, Guangzhou (China); Zhang, X. [State Key Laboratory of Oncology in South China, Guangzhou (China); Sun Yat-sen University Cancer Center, Departments of Thoracic Surgery, Guangzhou (China); An, X. [State Key Laboratory of Oncology in South China, Guangzhou (China); Sun Yat-sen University Cancer Center, Departments of Medical Oncology, Guangzhou (China); Cai, M.Y. [State Key Laboratory of Oncology in South China, Guangzhou (China); Sun Yat-sen University Cancer Center, Departments of Pathology, Guangzhou (China); Chen, G.; Kong, L.H.; Lin, J.Z.; Wan, D.S.; Pan, Z.Z.; Ding, P.R. [State Key Laboratory of Oncology in South China, Guangzhou (China); Sun Yat-sen University Cancer Center, Departments of Colorectal Surgery, Guangzhou (China)

    2014-02-15

    Conventional neoadjuvant chemoradiotherapy (CRT) is suboptimal for systemic control in locally advanced rectal cancer (LARC). To improve systemic control, we developed an alternative approach in which an intensified oxaliplatin and capecitabine (XELOX) chemotherapy regimen was administered concomitantly with radiation and extended to the resting period (consolidation chemotherapy) for high-risk LARC. The aim of the current study was to evaluate the short-term efficacy and toxicity of this strategy. Patients with high-risk LARC were treated with CRT. Two cycles of XELOX were administered concomitantly with radiation. Thereafter, an additional cycle of the same regimen was administered during the resting period after completion of CRT. Tumor response, toxicities and surgical complications were recorded. This study includes 36 patients treated with the above strategy. All patients completed the planned concurrent CRT. Because of grade 3 toxicities, 2 patients were unable to complete the additional chemotherapy. Grade 3 toxicities were leucopenia (2.8 %), diarrhea (2.8 %) and radiodermatitis (2.8 %). All patients underwent optimal surgery with total mesorectal excision (TME) and a sphincter-saving procedure was performed in 27 patients (75 %). There was no perioperative mortality. Postoperative complications developed in 7 patients (19.4 %). Pathologic complete regression (pCR),''nearly pCR'' (major regression), and moderate or minimal regression were achieved in 13 (36.1 %), 16 (44.4 %), and 7 patients (19.5 %), respectively. The preliminary results suggest that a XELOX regimen initially administered concomitantly with radiotherapy and then extended to the resting period in high-risk LARC patients is well tolerated. The strategy is highly effective in terms of pCR and nearly pCR rates, and thus warrants further investigation. (orig.)

  5. Extent and computed tomography appearance of early radiation induced lung injury for non-small cell lung cancer

    DEFF Research Database (Denmark)

    Bernchou, Uffe; Christiansen, Rasmus Lübeck; Asmussen, Jon Thor

    2017-01-01

    BACKGROUND AND PURPOSE: The present study investigates the extent and appearance of radiologic injury in the lung after radiotherapy for non-small cell lung cancer (NSCLC) patients and correlates radiologic response with clinical and dosimetric factors. METHODS AND MATERIALS: Eligible follow-up C...

  6. Radiation dose to the patient and the radiologist while performing on chest computed tomography: a program of early diagnosis of lung cancer, biopsy and treatment simulation guided radiation oncologist breast cancer; Dosis de radiacion al paciente y al radiologo durante la realizacion de tomografia computarizada en torax: progrma de diagnostico precoz del cancer de pulmon, biopsia guiada y simulacion del tratamiento oncologo radioterapico del cancer de mama

    Energy Technology Data Exchange (ETDEWEB)

    Pastor Sanchis, V.; Martinez Sanchez, J. M.; Palma Copete, J. D.; Crispin Contreras, V.; Casal Zamorano, E.; Dolores Alemany, V. de los; Gonzalez Perez, V.; Gimeno Olmo, J.; Guardino de la Flor, C.

    2011-07-01

    In this paper we determine the equivalent dose received by the operator and patient lung biopsies using thermoluminescence dosimeters, are established recommendations that this dose is as low as possible. It also reviews the acquisition protocols in both CT scans in early diagnosis program cited as the acquisition of CT for treatment planning dosimetric radiation oncologist in breast cancer.

  7. Dosimetric effects caused by couch tops and immobilization devices: report of AAPM Task Group 176.

    Science.gov (United States)

    Olch, Arthur J; Gerig, Lee; Li, Heng; Mihaylov, Ivaylo; Morgan, Andrew

    2014-06-01

    The dosimetric impact from devices external to the patient is a complex combination of increased skin dose, reduced tumor dose, and altered dose distribution. Although small monitor unit or dose corrections are routinely made for blocking trays, ion chamber correction factors, e.g., accounting for temperature and pressure, or tissue inhomogeneities, the dose perturbation of the treatment couch top or immobilization devices is often overlooked. These devices also increase skin dose, an effect which is also often ignored or underestimated. These concerns have grown recently due to the increased use of monolithic carbon fiber couch tops which are optimal for imaging for patient position verification but cause attenuation and increased skin dose compared to the "tennis racket" style couch top they often replace. Also, arc delivery techniques have replaced stationary gantry techniques which cause a greater fraction of the dose to be delivered from posterior angles. A host of immobilization devices are available and used to increase patient positioning reproducibility, and these also have attenuation and skin dose implications which are often ignored. This report of Task Group 176 serves to present a survey of published data that illustrates the magnitude of the dosimetric effects of a wide range of devices external to the patient. The report also provides methods for modeling couch tops in treatment planning systems so the physicist can accurately compute the dosimetric effects for indexed patient treatments. Both photon and proton beams are considered. A discussion on avoidance of high density structures during beam planning is also provided. An important aspect of this report are the recommendations the authors make to clinical physicists, treatment planning system vendors, and device vendors on how to make measurements of surface dose and attenuation and how to report these values. For the vendors, an appeal is made to work together to provide accurate couch top

  8. Dosimetric effects caused by couch tops and immobilization devices: Report of AAPM Task Group 176

    Energy Technology Data Exchange (ETDEWEB)

    Olch, Arthur J., E-mail: aolch@chla.usc.edu [Radiation Oncology Department, University of Southern California and Children' s Hospital Los Angeles, Los Angeles, California 90027 (United States); Gerig, Lee [Department of Physics, Ottawa Hospital Regional Cancer Centre, Carleton University, Ottawa, Ontario K1S 5B6, Canada and Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1N 6N5 (Canada); Li, Heng [Department of Radiation Physics, UT MD Anderson Cancer Center, Houston, Texas 77030 (United States); Mihaylov, Ivaylo [Department of Radiation Oncology Department, University of Miami, Miami, Florida 33136 (United States); Morgan, Andrew [The Beacon Centre, Musgrove Park Hospital, Taunton TA1 5DA (United Kingdom)

    2014-06-15

    The dosimetric impact from devices external to the patient is a complex combination of increased skin dose, reduced tumor dose, and altered dose distribution. Although small monitor unit or dose corrections are routinely made for blocking trays, ion chamber correction factors, e.g., accounting for temperature and pressure, or tissue inhomogeneities, the dose perturbation of the treatment couch top or immobilization devices is often overlooked. These devices also increase skin dose, an effect which is also often ignored or underestimated. These concerns have grown recently due to the increased use of monolithic carbon fiber couch tops which are optimal for imaging for patient position verification but cause attenuation and increased skin dose compared to the “tennis racket” style couch top they often replace. Also, arc delivery techniques have replaced stationary gantry techniques which cause a greater fraction of the dose to be delivered from posterior angles. A host of immobilization devices are available and used to increase patient positioning reproducibility, and these also have attenuation and skin dose implications which are often ignored. This report of Task Group 176 serves to present a survey of published data that illustrates the magnitude of the dosimetric effects of a wide range of devices external to the patient. The report also provides methods for modeling couch tops in treatment planning systems so the physicist can accurately compute the dosimetric effects for indexed patient treatments. Both photon and proton beams are considered. A discussion on avoidance of high density structures during beam planning is also provided. An important aspect of this report are the recommendations the authors make to clinical physicists, treatment planning system vendors, and device vendors on how to make measurements of surface dose and attenuation and how to report these values. For the vendors, an appeal is made to work together to provide accurate couch top

  9. Mechanical and dosimetric quality control for computer controlled radiotherapy treatment equipment.

    Science.gov (United States)

    Thompson, A V; Lam, K L; Balter, J M; McShan, D L; Martel, M K; Weaver, T A; Fraass, B A; Ten Haken, R K

    1995-05-01

    Modern computer controlled radiotherapy treatment equipment offers the possibility of delivering complex, multiple field treatments with minimal operator intervention, thus making multiple field conformal therapy practical. Conventional quality control programs are inadequate for this new technology, so new quality control procedures are needed. A reasonably fast, sensitive, and complete daily quality control program has been developed in our clinic that includes nearly automated mechanical as well as dosimetric tests. Automated delivery of these quality control fields is performed by the control system of the MM50 racetrack microtron, directed by the CCRS sequence processor [D. L. McShan and B. A. Fraass, Proceedings of the XIth International Conference on the use of computers in Radiation Therapy, 20-24 March 1994, Manchester, U.K. (North Western Medical Physics Department, Manchester, U.K., 1994), pp. 210-211], which controls the treatment process. The mechanical tests involve multiple irradiations of a single film to check the accuracy and reproducibility of the computer controlled setup of gantry and collimator angles, table orientation, collimator jaws, and multileaf collimator shape. The dosimetric tests, which involve multiple irradiations of an array of ionization chambers in a commercial dose detector (Keithly model 90100 Tracker System) rigidly attached to the head of the treatment gantry, check the output and symmetry of the treatment unit as a function of gantry and collimator angle and other parameters. For each of the dosimetric tests, readings from the five ionization chambers are automatically read out, stored, and analyzed by the computer, along with the geometric parameters of the treatment unit for that beam.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. SU-E-T-123: Dosimetric Comparison Between Portrait and Landscape Orientations in Radiochromic Film Dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kakinohana, Y [University of the Ryukyus, Okinawa (Japan); Toita, T; Kasuya, G; Ariga, T; Heianna, J; Murayama, S [University of the Ryukyus, Nishihara-cho, Okinawa (Japan)

    2014-06-01

    Purpose: To compare the dosimetric properties of radiochromic films with different orientation. Methods: A sheet of EBT3 film was cut into eight pieces with the following sizes: 15×15 cm2 (one piece), 5x15 cm{sup 2} (two) and 4×5 cm{sup 2} (five). A set of two EBT3 sheets was used at each dose level. Two sets were used changing the delivered doses (1 and 2 Gy). The 5×15 cm{sup 2} pieces were rotated by 90 degrees in relation to each other, such that one had landscape orientation and the other had portrait orientation. All 5×15 cm2 pieces were irradiated with their long side aligned with the x-axis of the radiation field. The 15×15 cm{sup 2} pieces were irradiated rotated at 90 degrees to each other. Five pieces, (a total of ten from two sheets) were used to obtain a calibration curve. The irradiated films were scanned using an Epson ES-2200 scanner and were analyzed using ImageJ software. In this study, no correction was applied for the nonuniform scanner signal that is evident in the direction of the scanner lamp. Each film piece was scanned both in portrait and landscape orientations. Dosimetric comparisons of the beam profiles were made in terms of the film orientations (portrait and landscape) and scanner bed directions (perpendicular and parallel to the scanner movement). Results: In general, portrait orientation exhibited higher noise than landscape and was adversely affected to a great extent by the nonuniformity in the direction of the scanner lamp. A significant difference in the measured field widths between the perpendicular and parallel directions was found for both orientations. Conclusion: Without correction for the nonuniform scanner signal in the direction of the scanner lamp, a landscape orientation is preferable. A more detailed investigation is planned to evaluate quantitatively the effect of orientation on the dosimetric properties of a film.

  11. Clinical Dosimetric Comparison among Different Intensity-Modulated Radiotherapy Plans for Nasopharyngeal Carcinoma

    Directory of Open Access Journals (Sweden)

    Changjiang Sun

    2014-03-01

    Full Text Available Objective: To compare the dosimetric differences of different intensity-modulated radiation therapy (IMRT plans for nasopharyngeal carcinoma (NPC. Methods: 5-, 7- and 9-fields of IMRT plans in 16 NPC patients were respectively designed and synchronous dimention technology was applied to compare the dosimetric differences in target areas and involved organs. Results: The recovery rate in target area was 95% while the plan was evidently worse in 5-field than in 7- and 9-fields (P < 0.05. Whereas the maximum dosage (Dmax, mean dosage (Dmean and minimum dosage (Dmin were similar between 7- and 9-fields (P > 0.05, which were obviously lower in 5-field, and the differences were both significant (P < 0.05. In addition, the conformity and homogeneity indexes in target area had no significant difference between 7- and 9-fields, but were markedly better than in 5-field (P < 0.05. Indexes in each involved organs were the lowest in 5-field than in other fields (P < 0.05, but were similar between 7- and 9-fields (P > 0.05, which were all lower than tolerant dosage. As for BODY, there were significant differences in V10 - V20 between 5-field and other fields (P < 0.05, but were similar in V25 - V30 (P > 0.05. However, 7- and 9-fields were similar in V10 - V20 (P > 0.05. Conclusion: 7-field IMRT plan is the optimal one for NPC on both clinical dosimetric requirements and field-establishment principles.

  12. SU-C-210-06: Quantitative Evaluation of Dosimetric Effects Resulting From Positional Variations of Pancreatic Tumor Volumes

    Energy Technology Data Exchange (ETDEWEB)

    Yu, S; Sehgal, V; Wei, R; Lawrenson, L; Kuo, J; Hanna, N; Ramsinghani, N; Daroui, P; Al-Ghazi, M [University of California, Orange, CA (United States)

    2015-06-15

    Purpose: The aim of this study is to quantify dosimetric effects resulting from variation in pancreatic tumor position assessed by bony anatomy and implanted fiducial markers Methods: Twelve pancreatic cancer patients were retrospectively analyzed for this study. All patients received modulated arc therapy (VMAT) treatment using fiducial-based Image Guided Radiation Therapy (IGRT) to the intact pancreas. Using daily orthogonal kV and/or Cone beam CT images, the shift needed to co-register the daily pre-treatment images to reference CT from fiducial to bone (Fid-Bone) were recorded as Left-Right (LR), Anterior-Posterior (AP) and Superior-Inferior (SI). The original VMAT plan iso-center was shifted based on KV bone matching positions at 5 evenly spaced fractions. Dose coverage of the planning target volumes (PTVs) (V100%), mean dose to liver, kidney and stomach/duodenum were assessed in the modified plans. Results: A total of 306 fractions were analyzed. The absolute fiducial-bone positional shifts were greatest in the SI direction, (AP = 2.7 ± 3.0, LR = 2.8 ± 2.8, and SI 6.3 ± 7.9 mm, mean ± SD). The V100% was significantly reduced by 13.5%, (Fid-Bone = 95.3 ± 2.0 vs. 82.3 ± 11.8%, p=0.02). This varied widely among patients (Fid-Bone V100% Range = 2–60%), where 33% of patients had a reduction in V100% of more than 10%. The impact on OARs was greatest to the liver (Fid-Bone= 14.6 vs. 16.1 Gy, 10%), and stomach, (Fid-Bone = 23.9 vx. 25.5 Gy, 7%), however was not statistically significant (p=0.10 both). Conclusion: Compared to matching by fiducial markers, matching by bony anatomy would have substantially reduced the PTV coverage by 13.5%. This reinforces the importance of online position verification based on fiducial markers. Hence, implantation of fiducial markers is strongly recommended for pancreatic cancer patients undergoing intensity modulated radiation therapy treatments.

  13. Accelerated partial breast irradiation in an Asian population: dosimetric findings and preliminary results of a multicatheter interstitial program

    Directory of Open Access Journals (Sweden)

    Koh YV

    2016-09-01

    Full Text Available Yaling Vicky Koh,1 Poh Wee Tan,1 Shaik Ahmad Buhari,2 Philip Iau,2 Ching Wan Chan,2 Liang Shen,3 Sing Huang Tan,4 Johann I-Hsiung Tang1 1Department of Radiation Oncology, National University Cancer Institute Singapore, 2Department of Surgery, National University Hospital, 3Department of Medicine, Biostatistics Unit, National University of Singapore, 4Department of Medical Oncology, National University Cancer Institute Singapore, Singapore Introduction: Accelerated partial breast irradiation (APBI using the multicatheter method has excellent cosmesis and low rates of long-term toxicity. However, there are few studies looking at the feasibility of this procedure and the outcomes in an Asian population. This study aims to look at outcomes at our hospital.Methods: We identified 121 patients treated with APBI at our center between 2008 and 2014. The median follow-up for our patient group was 30 months (range 3.7–66.5. The prescribed dose per fraction was 3.4 Gy in 10 fractions. In this study population, 71% of the patients were Chinese while 15% (n=19 were of other Asian ethnicity.Results: In this study, the median breast volume was 850 cc (range 216–2,108 with 59.5% (n=72 patients with a breast volume of <1,000 cc. The average planning target volume was 134 cc (range 28–324. The number of catheters used ranged from 8 to 25 with an average of 18 catheters used per patient. We achieved an average dose homogeneity index of 0.76 in our patients. The average D90(% was 105% and the average D90(Gy was 3.6 Gy per fraction. The median volume receiving 100% of the prescribed dose (V100 was 161.7 cc (range 33.9–330.1, 150% of the prescribed dose (V150 and 200% of the prescribed dose (V200 was 39.4 cc (range 14.6–69.6 and 14.72 cc (range 6.48–22.25, respectively. Our dosimetric outcomes were excellent even in patients with breast volume under 1,000 cc. There were no cases of grade 3 skin toxicity or acute pneumonitis. Two patients had a

  14. Volumetric modulated arc planning for lung stereotactic body radiotherapy using conventional and unflattened photon beams: a dosimetric comparison with 3D technique

    Directory of Open Access Journals (Sweden)

    Zhang Geoffrey G

    2011-11-01

    Full Text Available Abstract Purpose Frequently, three-dimensional (3D conformal beams are used in lung cancer stereotactic body radiotherapy (SBRT. Recently, volumetric modulated arc therapy (VMAT was introduced as a new treatment modality. VMAT techniques shorten delivery time, reducing the possibility of intrafraction target motion. However dose distributions can be quite different from standard 3D therapy. This study quantifies those differences, with focus on VMAT plans using unflattened photon beams. Methods A total of 15 lung cancer patients previously treated with 3D or VMAT SBRT were randomly selected. For each patient, non-coplanar 3D, coplanar and non-coplanar VMAT and flattening filter free VMAT (FFF-VMAT plans were generated to meet the same objectives with 50 Gy covering 95% of the PTV. Two dynamic arcs were used in each VMAT plan. The couch was set at ± 5° to the 0° straight position for the two non-coplanar arcs. Pinnacle version 9.0 (Philips Radiation Oncology, Fitchburg WI treatment planning system with VMAT capabilities was used. We analyzed the conformity index (CI, which is the ratio of the total volume receiving at least the prescription dose to the target volume receiving at least the prescription dose; the conformity number (CN which is the ratio of the target coverage to CI; and the gradient index (GI which is the ratio of the volume of 50% of the prescription isodose to the volume of the prescription isodose; as well as the V20, V5, and mean lung dose (MLD. Paired non-parametric analysis of variance tests with post-tests were performed to examine the statistical significance of the differences of the dosimetric indices. Results Dosimetric indices CI, CN and MLD all show statistically significant improvement for all studied VMAT techniques compared with 3D plans (p Conclusion Besides the advantage of faster delivery times, VMAT plans demonstrated better conformity to target, sharper dose fall-off in normal tissues and lower dose to

  15. Energy absorption buildup factors for thermoluminescent dosimetric materials and their tissue equivalence

    DEFF Research Database (Denmark)

    Manohara, S.R.; Hanagodimath, S.M.; Gerward, Leif

    2010-01-01

    -absorption buildup factor data have been studied as a function of penetration depth and incident photon energy. Buildup factors determined in the present work should be useful in radiation dosimetry, diagnostics and therapy. The tissue equivalence of TLD materials is also discussed.......Gamma ray energy-absorption buildup factors were computed using the five-parameter geometric progression (G-P) fitting formula for seven thermoluminescent dosimetric (TLD) materials in the energy range 0.015-15 MeV, and for penetration depths up to 40 mfp (mean free path). The generated energy...

  16. Comparison of dosimetric standards of USA and France for HDR brachytherapy

    Science.gov (United States)

    Douysset, Guilhem; Gouriou, Jean; Delaunay, Frank; DeWerd, Larry; Stump, Kurt; Micka, John

    2005-05-01

    A bilateral comparison of national dosimetric standards for high dose rate brachytherapy has been conducted between the Laboratoire National Henri Becquerel and the University of Wisconsin Accredited Dosimetry Calibration Laboratory. A complete overview of the methods that are currently in use to establish the two national standards is given. The comparison has been carried out using well-type transfer ionization chambers. Three units have been calibrated in both laboratories, and calibration coefficients have been compared. The discrepancies between the two measurements are within 0.3%.

  17. The revised International Commission on Radiological Protection (ICRP) dosimetric model for the human respiratory tract

    Energy Technology Data Exchange (ETDEWEB)

    Bair, W.J.

    1992-05-01

    A task group has revised the dosimetric model of the respiratory tract used to calculate annual limits on intake of radionuclides. The revised model can be used to project respiratory tract doses for workers and members of the public from airborne radionuclides and to assess past exposures. Doses calculated for specific extrathoracic and thoracic tissues can be adjusted to account for differences in radiosensitivity and summed to yield two values of dose for the respiratory tract that are applicable to the ICRP tissue weighted dosimetry system.

  18. [Dosimetric characteristics of the bremsstrahlung beam from the LUE-15M medical linear electron accelerator].

    Science.gov (United States)

    Vatnitskiĭ, S M; Ermakov, I A; Puzanov, V P; Sinitsyn, R V; Cherviakov, A M

    1983-10-01

    The paper presents methods and results of a study of radiation-physical characteristics of inhibitory radiation beam with the Grenz energy of 15MeV generated by an electron linear accelerator LUE-15M. Special emphasis is laid on primary dosimetric information used for the planning of radiotherapy: depth doses, beam profiles, dose functions of a collimated beam. It has been shown that in general the accelerator meets the requirements of the International Electrotechnical Commission. General error in the focal absorbed dose at the expense of variable parameters of the accelerator was evaluated. It does not exceed +/- 3.5%.

  19. Dosimetric and spectrometric neutron measurements around an annular vessel containing a plutonium nitrate fissile solution

    CERN Document Server

    Tournier, B; Medioni, R; Rich, C; Mussoni, F; Camus, L; Pichenot, G; Crovisier, P; Cutarella, D; Asselineau, B; Groetz, J E

    2002-01-01

    The new ICPR60 recommendations and the consideration of the ALARA principle have led the operators of nuclear facilities to evaluate with a higher care, the doses received by workers. The aim of this paper is to present a recent study concerning mixed field characterisation at a workplace located in a reprocessing laboratory. As a first step, neutron spectrum determination was achieved by two ways: simulation using MCNP code and experimental measurements with Bonner spheres and recoil proton counters. Neutron spectrum allowed the evaluation of dosimetric quantities. Measurements were then performed with different devices routinely used in radioprotection. The describe the measurement techniques, present the results obtained, and finally compare and discuss them.

  20. Determination of dosimetric and kinetic features of gamma irradiated solid calcium ascorbate dihydrate using ESR spectroscopy

    Science.gov (United States)

    Tuner, H.

    2013-01-01

    Effects of gamma radiation on solid calcium ascorbate dihydrate were studied using electron spin resonance (ESR) spectroscopy. Irradiated samples were found to present two specific ESR lines with shoulder at low and high magnetic field sides. Structural and kinetic features of the radicalic species responsible for experimental ESR spectrum were explored through the variations of the signal intensities with applied microwave power, variable temperature, high-temperature annealing and room temperature storage time studies. Dosimetric potential of the sample was also determined using spectrum area and measured signal intensity measurements. It was concluded that three radicals with different spectroscopic and kinetic features were produced upon gamma irradiation.

  1. Dosimetric characteristics of a TLD dosemeter with extremities; Caracteristicas dosimetricas de un dosimetro TLD de extremidades

    Energy Technology Data Exchange (ETDEWEB)

    Molina P, D.; Diaz B, E.; Lien V, R. [Centro de Proteccion e Higiene de las Radiaciones, CPHR, Apdo.Postal 6195, Habana 6, CP 10600, Ciudad Habana (Cuba)

    1999-07-01

    It was designed a TLD dosemeter for the monitoring of the extremities. This one consists in a metallic ring with a circular orifice where is arranged a T L detector of LiF: Mg,Ti (Model JR1152C) 5 x 5 x 0.8 mm{sup 3} covered by a polyethylene fine layer. In this work were studied the dosimetric properties of the dosemeter for its application in the dosimetry of extremities for photonic radiation. the results obtained allow conclude that the designed dosemeter can be used for the extremities monitoring. (Author)

  2. Dosimetric analysis of SMD phototransistor in dental phantom of different geometries

    Energy Technology Data Exchange (ETDEWEB)

    Belinato, W.; Magalhaes, C. M. S.; Souza, D. N. [Departmento de Fisica, Universidade Federal de Sergipe, Av. Marechal Rondon s/n, 49.100-000, Rosa Elze, Sao Cristovao-SE (Brazil); Santos, L. A. P. [Laboratorio de Instrumentacao Nuclear, Centro Regional de Ciencias Nucleares, Av. Professor Luiz Freire, 200, 50-740-540, Recife-PE (Brazil)

    2009-10-15

    A commercial surface mount device (SMD) phototransistor, OP520, was inserted in two dental phantoms for dosimetric analysis. The irradiations were accomplished in a dental x-ray equipment of 80 kV using different exposition times. A standard ionization chamber was irradiated at the same conditions and the air kerma measured with it was compared with the electrical charge evaluated by the phototransistor. The results showed satisfactory correspondence among the detectors readings. Moreover, the phototransistor showed up quite sensitively for dental applications, allowing verifying the variations for the different phantoms configurations. (Author)

  3. Evaluation of dosimetric parameters of a commercial semiconductor device in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Magalhaes, C. M. S.; Sobrinho, M. C.; Souza, D. N. [Departmento de Fisica, Universidade Federale de Sergipe, Av. Marechal Rondon s/n, 49.100-000, Rosa Elze, Sao Cristovao-SE (Brazil); Santos, L. A. P. [Laboratorio de Instrumentacao Nuclear, Centro Regional de Ciencias Nucleares, Av. Professor Luiz Freire, 200, 50.740-540 Recife-PE (Brazil)

    2009-10-15

    Semiconductor devices have been widely used for dosimetry in radiotherapy and more recently in diagnostic radiology. In order to evaluate the performance of a phototransistor as a radiation detector in computed tomography (CT), some dosimetric parameters were evaluated, such as: repetitive, angular dependence, response for different tube potentials, dose and dose rate dependence. The irradiation was performed with the detector on the axis of rotation of a X-ray tube in CT scanner. The results showed that, making the necessary corrections, it is possible to use the phototransistor for dosimetry in tomography. (Author)

  4. Dosimetric equivalence of nonstandard HDR brachytherapy catheter patterns

    Energy Technology Data Exchange (ETDEWEB)

    Cunha, J. A. M.; Hsu, I-C.; Pouliot, J. [University of California, San Francisco, California 94115 (United States)

    2009-01-15

    Purpose: To determine whether alternative high dose rate prostate brachytherapy catheter patterns can result in similar or improved dose distributions while providing better access and reducing trauma. Materials and Methods: Standard prostate cancer high dose rate brachytherapy uses a regular grid of parallel needle positions to guide the catheter insertion. This geometry does not easily allow the physician to avoid piercing the critical structures near the penile bulb nor does it provide position flexibility in the case of pubic arch interference. This study used CT datasets with 3 mm slice spacing from ten previously treated patients and digitized new catheters following three hypothetical catheter patterns: conical, bi-conical, and fireworks. The conical patterns were used to accommodate a robotic delivery using a single entry point. The bi-conical and fireworks patterns were specifically designed to avoid the critical structures near the penile bulb. For each catheter distribution, a plan was optimized with the inverse planning algorithm, IPSA, and compared with the plan used for treatment. Irrelevant of catheter geometry, a plan must fulfill the RTOG-0321 dose criteria for target dose coverage (V{sub 100}{sup Prostate}>90%) and organ-at-risk dose sparing (V{sub 75}{sup Bladder}<1 cc, V{sub 75}{sup Rectum}<1 cc, V{sub 125}{sup Urethra}<<1 cc). Results: The three nonstandard catheter patterns used 16 nonparallel, straight divergent catheters, with entry points in the perineum. Thirty plans from ten patients with prostate sizes ranging from 26 to 89 cc were optimized. All nonstandard patterns fulfilled the RTOG criteria when the clinical plan did. In some cases, the dose distribution was improved by better sparing the organs-at-risk. Conclusion: Alternative catheter patterns can provide the physician with additional ways to treat patients previously considered unsuited for brachytherapy treatment (pubic arch interference) and facilitate robotic guidance of

  5. Comparison of dosimetric characteristics of Siemens virtual and physical wedges for ONCOR linear accelerator

    Directory of Open Access Journals (Sweden)

    Attalla Ehab

    2010-01-01

    Full Text Available Dosimetric properties of virtual wedge (VW and physical wedge (PW in 6- and 10-MV photon beams from a Siemens ONCOR linear accelerator, including wedge factors, depth doses, dose profiles, peripheral doses, are compared. While there is a great difference in absolute values of wedge factors, VW factors (VWFs and PW factors (PWFs have a similar trend as a function of field size. PWFs have stronger depth dependence than VWF due to beam hardening in PW fields. VW dose profiles in the wedge direction, in general, match very well with those of PW, except in the toe area of large wedge angles with large field sizes. Dose profiles in the nonwedge direction show a significant reduction in PW fields due to off-axis beam softening and oblique filtration. PW fields have significantly higher peripheral doses than open and VW fields. VW fields have similar surface doses as the open fields, while PW fields have lower surface doses. Surface doses for both VW and PW increase with field size and slightly with wedge angle. For VW fields with wedge angles 45° and less, the initial gap up to 3 cm is dosimetrically acceptable when compared to dose profiles of PW. VW fields in general use less monitor units than PW fields.

  6. Identification and dosimetric features of γ-irradiated cefadroxil by electron spin resonance

    Science.gov (United States)

    Aydaş, Canan; Polat, Mustafa; Korkmaz, Mustafa

    2008-01-01

    In the present work, electron spin resonance (ESR) identification of γ-irradiated cefadroxil monohydrate (CM), duricef capsule (DC) and duricef suspension (DS) and their potential use as normal and/or accidental dosimetric materials were investigated in the dose range of 1-25 kGy. Although unirradiated samples did not exhibit any ESR signals, irradiated samples were observed to present ESR spectra with many resonance lines originating from radiation induced radical or radicals. Dose-response curves associated with the resonance peak heights of CM ( I1, I2) and DS ( I3, I4, I5, I6) were found to follow linear and power functions of applied radiation dose, respectively. Simulation calculations were performed to determine the structure and spectral parameters of the radiation-induced radicalic species involved in the formation of experimental ESR spectrum of CM using, as input, the room temperature signal intensity data obtained for a sample irradiated at dose of 10 kGy. Kinetic behaviors and activation energies of the radicalic species were also calculated using the data obtained from annealing studies performed at five different temperatures. The presence of detectable signal intensities even after a storage period of 100 days was considered as providing an opportunity in the discrimination of irradiated CM and DS from unirradiated ones. Basing on room temperature signal intensity decay and dose-response data, it was concluded that CM and DS present the features of a good dosimetric material.

  7. Dosimetric effects of beam size and collimation of epithermal neutrons for boron neutron capture therapy.

    Science.gov (United States)

    Yanch, J C; Harling, O K

    1993-08-01

    A series of studies of "ideal" beams has been carried out using Monte Carlo simulation with the goal of providing guidance for the design of epithermal beams for boron neutron capture therapy (BNCT). An "ideal" beam is defined as a monoenergetic, photon-free source of neutrons with user-specified size, shape and angular dependence of neutron current. The dosimetric behavior of monoenergetic neutron beams in an elliptical phantom composed of brain-equivalent material has been assessed as a function of beam diameter and neutron emission angle (beam angle), and the results are reported here. The simulation study indicates that substantial differences exist in the dosimetric behavior of small and large neutron beams (with respect to the phantom) as a function of the extent of beam collimation. With a small beam, dose uniformity increases as the beam becomes more isotropic (less collimated); the opposite is seen with large beams. The penetration of thermal neutrons is enhanced as the neutron emission angle is increased with a small beam; again the opposite trend is seen with large beams. When beam size is small, the dose delivered per neutron is very dependent on the extent of beam collimation; this does not appear to be the case with a larger beam. These trends in dose behavior are presented graphically and discussed in terms of their effect on several figures of merit, the advantage depth, the advantage ratio, and the advantage depth-dose rate. Tables giving quick summaries of these results are provided.

  8. A complete dosimetric characterization of two {sup 90}Sr-{sup 90}Y dermatologic applicators

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, T.S. [Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, Sao Paulo (Brazil); Fernandes, M.A.R. [Faculdade de Medicina de Botucatu, UNESP, Departamento de Dermatologia e Radioterapia, Sao Paulo (Brazil); Yoriyaz, H., E-mail: hyoriyaz@ipen.b [Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, Sao Paulo (Brazil); Antonio, P.L. [Instituto de Pesquisas Energeticas e Nucleares, IPEN/CNEN, Sao Paulo (Brazil)

    2011-03-11

    A complete dosimetric characterization of two Amershan {sup 90}Sr-{sup 90}Y dermatologic applicators is described in this present work. The dosimetric parameters analyzed are: percentage depth dose curve, radial dose distribution, non-uniformity and asymmetry. Both applicators are planar-circular having 22.57 and 9.0 mm diameters. In the range where the percentage depth dose goes from 100% down to 20%, the measured percentage depth dose and that obtained by the Monte Carlo simulation have shown maximum discrepancy of 5.3% for both applicators. The radial dose distribution has been measured at several depths using a GafChromic EBT QD+ films and it was also calculated by simulation. The discrepancies found did not exceed 5.9% up to the depth of 1.8 mm, where the percentage depth dose drops to 40% of the maximum. The maximum non-uniformity and asymmetry are 1.7% and 5.3% for the first applicator and 22.7% and 25.9% for the second applicator, respectively. Both applicators meet the specification for the maximum non-uniformity established by the adopted protocol, whose limit is 30%. As for the asymmetry the limit is 20% and the second applicator exceeded it in about 5.9%.

  9. Dosimetric properties of bio minerals applied to high-dose dosimetry using the TSEE technique

    Energy Technology Data Exchange (ETDEWEB)

    Vila, G. B.; Caldas, L. V. E., E-mail: gbvila@ipen.br [Instituto de Pesquisas Energeticas e Nucleares / CNEN, Av. Lineu Prestes 2242, Cidade Universitaria, 05508-000 Sao Paulo (Brazil)

    2014-08-15

    The study of the dosimetric properties such as reproducibility, the residual signal, lower detection dose, dose-response curve and fading of the thermally stimulated emission exo electronic (TSEE) signal of Brazilian bio minerals has shown that these materials present a potential use as radiation dosimeters. The reproducibility within ± 10% for oyster shell, mother-of-pearl and coral reef samples showed that the signal dispersion is small when compared with the mean value of the measurements. The study showed that the residual signal can be eliminated with a thermal treatment at 300 grades C/1 h. The lower detection dose of 9.8 Gy determined for the oyster shell samples when exposed to beta radiation and 1.6 Gy for oyster shell and mother-of-pearl samples when exposed to gamma radiation can be considered good, taking into account the high doses of this study. The materials presented linearity at the dose response curves in some ranges, but the lack of linearity in other cases presents no problem since a good mathematical description is possible. The fading study showed that the loss of TSEE signal can be minimized if the samples are protected from interferences such as light, heat and humidity. Taking into account the useful linearity range as the main dosimetric characteristic, the tiger shell and oyster shell samples are the most suitable for high-dose dosimetry using the TSEE technique. (Author)

  10. A Combined Tissue Kinetics and Dosimetric Model of Respiratory Tissue Exposed to Radiation

    Energy Technology Data Exchange (ETDEWEB)

    John R. Ford

    2005-11-01

    Existing dosimetric models of the radiation response of tissues are essentially static. Consideration of changes in the cell populations over time has not been addressed realistically. For a single acute dose this is not a concern, but for modeling chronic exposures or fractionated acute exposures, the natural turnover and progression of cells could have a significant impact on a variety of endpoints. This proposal addresses the shortcomings of current methods by combining current dose-based calculation techniques with information on the cell turnover for a model tissue. The proposed model will examine effects at the single-cell level for an exposure of a section of human bronchiole. The cell model will be combined with Monte Carlo calculations of doses to cells and cell nuclei due to varying dose-rates of different radiation qualities. Predictions from the model of effects on survival, apoptosis rates, and changes in the number of cycling and differentiating cells will be tested experimentally. The availability of dynamic dosimetric models of tissues at the single-cell level will be useful for analysis of low-level radiation exposures and in the development of new radiotherapy protocols.

  11. Recovery of α-Al{sub 2}O{sub 3} from ionizing radiation dosimetric sensors

    Energy Technology Data Exchange (ETDEWEB)

    Sanches, Edgar Aparecido, E-mail: sanches.ufam@gmail.com [Universidade Federal do Amazonas (UFAM), Manaus, AM (Brazil). Dept. de Fisica; Costalonga, Ademir Geraldo Cavallari; Mascarenhas, Yvonne Primerano [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Institute de Fisica; Nascimento, Luana de Freitas [Belgium Nuclear Research Centre, SCK-CEN, Mol (Belgium); Mascarenhas, Yvone Maria [SAPRA S/A Servico de Assessoria e Protecao Radiologica, Sao Carlos, SP, (Brazil)

    2015-01-15

    Corundum, sapphire or α-Al{sub 2}O{sub 3} is an important technological material in many optical and electronic applications such as solid-state lasers, optical windows and, more recently, as a radiation detector. Landauer (Glenwood, IL, USA) accumulated large number of archived and stored Luxel™ dosemeters composed of Al{sub 2}O{sub 3}:C, which were subjected to a recovery process. Due to the importance of this advanced crystalline material in OSL dosimetry, a recovery process was developed based on the dosemeters calcination and Al{sub 2}O{sub 3}:C has been reused in manufacturing of new dosemeters. This paper does not aim to optimize the recovery process, but provides an opportunity to study the involved process parameters and to recover this valuable crystalline material from used dosemeters. To the best of our knowledge no other recovery process involving this dosimetric material was described in scientific literature. Fourier Transform Infrared Spectrometry (FTIR), Thermogravimetry/Differential Thermoanalysis (TG/DTA), Differential Scanning Calorimetry (DSC), X-ray Diffraction (XRD), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Optically Stimulated Luminescence (OSL) and Rietveld Refinement were used to characterize the recovered material and to check for the stability of its structural and dosimetric properties. (author)

  12. Dosimetric study of thermoluminescent detectors in clinical photon beams using liquid water and PMMA phantoms

    Energy Technology Data Exchange (ETDEWEB)

    Matsushima, Luciana C., E-mail: lmatsushima@ipen.br [Gerencia de Metrologia das Radiacoes (GMR) - Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, CEP: 05508-000, Sao Paulo, SP (Brazil); Veneziani, Glauco R. [Gerencia de Metrologia das Radiacoes (GMR) - Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, CEP: 05508-000, Sao Paulo, SP (Brazil); Sakuraba, Roberto K. [Gerencia de Metrologia das Radiacoes (GMR) - Instituto de Pesquisas Energeticas e Nucleares (IPEN-CNEN/SP), Av. Prof. Lineu Prestes, 2242, Cidade Universitaria, CEP: 05508-000, Sao Paulo, SP (Brazil); Sociedade Beneficente Israelita Brasileira - Hospital Albert Einstein (HAE), Avenida Albert Einstein, 665, Morumbi, CEP: 05652-000, Sao Paulo, SP (Brazil); Cruz, Jose C. da [Sociedade Beneficente Israelita Brasileira - Hospital Albert Einstein (HAE), Avenida Albert Einstein, 665, Morumbi, CEP: 05652-000, Sao Paulo, SP (Brazil)

    2012-07-15

    The purpose of this study was the dosimetric evaluation of thermoluminescent detectors of calcium sulphate doped with dysprosium (CaSO{sub 4}:Dy) produced by IPEN compared to the TL response of lithium fluoride doped with magnesium and titanium (LiF:Mg,Ti) dosimeters and microdosimeters produced by Harshaw Chemical Company to clinical photon beams dosimetry (6 and 15 MV) using liquid water and PMMA phantoms. - Highlights: Black-Right-Pointing-Pointer Dosimetric study of thermoluminescent detectors of CaSO{sub 4}:Dy, LiF:Mg,Ti and {mu}LiF:Mg,Ti. Black-Right-Pointing-Pointer Clinical (6 and 15 MV) photon beams dosimetry using liquid water and PMMA phantom. Black-Right-Pointing-Pointer Linear behavior to the dose range (0.1 to 5 Gy). Black-Right-Pointing-Pointer TL response reproducibility better than {+-}4.34%. Black-Right-Pointing-Pointer CaSO{sub 4}:Dy represent a cheaper alternative to the TLD-100.

  13. Three dimensional dose verification of VMAT plans using the Octavius 4D dosimetric system

    Science.gov (United States)

    Arumugam, Sankar; Xing, Aitang; Young, Tony; Thwaites, David; Holloway, Lois

    2015-01-01

    The Octavius 4D dosimetric system generates a 3D dose matrix based on a measured planar dose and user supplied Percentage Depth Dose (PDD) data. The accuracy of 3D dose matrices reconstructed by the Octavius 4D dosimetric system was systematically studied for an open static field, an open arc field and clinical VMAT plans. The Octavius reconstructed 3D dose matrices were compared with the Treatment Planning System (TPS) calculated 3D dose matrices using 3D gamma (γ) analysis with 2%/2mm and 3%/3mm tolerance criteria. The larger detector size in the 2D detector array of the Octavius system resulted in failed voxels in the high dose gradient regions. For the open arc fields mean (1σ) γ pass rates of 84.5(8.9) % and 94.2(4.5) % were observed with 2%/2mm and 3%/3mm tolerance criteria respectively and for clinical VMAT plans mean (1σ) γ pass rates of 86.8(3.5) % and 96.7(1.4) % were observed.

  14. [Mathematical simulation support to the dosimetric monitoring on the Russian segment of the International Space Station].

    Science.gov (United States)

    Mitrikas, V G

    2014-01-01

    To ensure radiation safety of cosmonauts, it is necessary not only to predict, but also to reconstruct absorbed dose dynamics with the knowledge of how long cosmonauts stay in specific space vehicle compartments with different shielding properties and lacking equipment for dosimetric monitoring. In this situation, calculating is one and only way to make a correct estimate of radiation exposure of cosmonaut's organism as a whole (tissue-average dose) and of separate systems and organs. The paper addresses the issues of mathematical simulation of epy radiation environment of standard dosimetric instruments in the Russian segments of the International Space Station (ISS RS). Results of comparing the simulation and experimental data for the complement of dosimeters including ionization chamber-based radiometer R-16, DB8 dosimeters composed of semiconductor detectors, and Pille dosimeters composed of thermoluminescent detectors evidence that the current methods of simulation in support of the ISS RS radiation monitoring provide a sufficiently good agreement between the calculated and experimental data.

  15. Use of TLD-100 to verify a dosimetric method for total electron skin irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Mesa, F.; Sosa, M. [Physics Institute, University of Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 Leon, Guanajuato (Mexico)

    2007-07-01

    Full text: A clinical dosimetric method for generating a homogeneous field of radiation around of patients under treatment of total skin electron irradiation and its verification using thermoluminescent dosimetry is presented. The irradiations were performed utilizing a 6 MeV electron beam generated by a Varian Clinac 21EX linear accelerator installed in the oncology unit of the IMSS-Tl hospital in Leon. Levels of radiation for diverse adjustment performed in the treatment planning system of the lineal accelerator and registered to different treatment distances using a computerized water phantom system were studied. A large batch of TLD-100 chips calibrated in terms of air-kerma rate to the standard treatment distance and positioned in an anthropomorphic Alderson Random Phantom was used. Dose verification and comparison with the measurements made with the computerized system were analyzed. A single field electron beam for treatment of total skin irradiation was implemented. Preliminary results indicate that the levels of dose homogeneities were larger than 90% for distances up to 3.0 m. The results suggest that the method developed is a reliable for delivering an electron beam with significantly homogeneity for these treatments. Analyses and results of both thermoluminescent and computerized dosimetric system calibrations are also presented. (Author)

  16. Dosimetric properties of dysprosium doped calcium magnesium borate glass subjected to Co-60 gamma ray

    Energy Technology Data Exchange (ETDEWEB)

    Omar, R. S., E-mail: ratnasuffhiyanni@gmail.com; Wagiran, H., E-mail: husin@utm.my; Saeed, M. A. [Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Johor Bahru (Malaysia)

    2016-01-22

    Thermoluminescence (TL) dosimetric properties of dysprosium doped calcium magnesium borate (CMB:Dy) glass are presented. This study is deemed to understand the application of calcium as the modifier in magnesium borate glass with the presence of dysprosium as the activator to be performed as TL dosimeter (TLD). The study provides fundamental knowledge of a glass system that may lead to perform new TL glass dosimetry application in future research. Calcium magnesium borate glass systems of (70-y) B{sub 2}O{sub 3} − 20 CaO – 10 MgO-(y) Dy{sub 2}O{sub 3} with 0.05  mol % ≤ y ≤ 0.7  mol % of dyprosium were prepared by melt-quenching technique. The amorphous structure and TL properties of the prepared samples were determined using powder X-ray diffraction (XRD) and TL reader; model Harshaw 4500 respectively. The samples were irradiated to Co-60 gamma source at a dose of 50 Gy. Dosimetric properties such as annealing procedure, time temperature profile (TTP) setting, optimization of Dy{sub 2}O{sub 3} concentration of 0.5 mol % were determined for thermoluminescence dosimeter (TLD) reader used.

  17. MRI-guided single fraction ablative radiotherapy for early-stage breast cancer : a brachytherapy versus volumetric modulated arc therapy dosimetry study

    NARCIS (Netherlands)

    Charaghvandi, Ramona K; den Hartogh, Mariska D; van Ommen, Anne-Mar L N; de Vries, Wilfred J H; Scholten, Vincent; Moerland, Rien; Philippens, Mariëlle E P; Schokker, Rogier I; van Vulpen, Marco; van Asselen, B; van den Bongard, Desirée H J G

    2015-01-01

    BACKGROUND AND PURPOSE: A radiosurgical treatment approach for early-stage breast cancer has the potential to minimize the patient's treatment burden. The dosimetric feasibility for single fraction ablative radiotherapy was evaluated by comparing volumetric modulated arc therapy (VMAT) with an inter

  18. Breathing adapted radiotherapy of breast cancer: reduction of cardiac and pulmonary doses using voluntary inspiration breath-hold

    DEFF Research Database (Denmark)

    Pedersen, Anders N; Korreman, Stine; Nyström, Håkan

    2004-01-01

    BACKGROUND AND PURPOSE: Adjuvant radiotherapy of breast cancer using wide tangential photon fields implies a risk of late cardiac and pulmonary toxicity. This CT-study evaluates the detailed potential dosimetric consequences of applying breathing adapted radiotherapy (BART), and the feasibility......%. CONCLUSIONS: Irradiated cardiac volumes can consistently be reduced for left-sided breast cancers using DIBH for wide tangential treatment fields. Additionally, substantial dose reductions in the lung are observed for both right- and left-sided tumours....

  19. Dosimetric intercomparison between protons and electrons therapies applied to retinoblastoma; Intercomparacao dosimetrica entre terapias de protons e eletrons aplicada ao retinoblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Flavia Vieira

    2008-07-01

    In this work we propose a construction of a simple human eye model in order to simulate the dosimetric response for a treatment with protons and electrons in a retinoblastoma cancer. The computational tool used in this simulation was the Geant4 code, in the version 4.9.1, all these package are free and permit simulate the interaction of radiation with matter. In our simulation we use a box with 4 cm side, with water, for represent the human eye. The simulation was performed considering mono energetics beams of protons and electrons with energy range between 50 and 70 MeV for protons and 2 and 10 MeV for electrons. The simulation was based on the advanced hadron therapy example of the Geant 4 code. In these example the phantom is divided in voxels with 0.2 mm side and it is generated the energy deposited in each voxel. The simulation results show the energy deliver in each voxel, with these energie we can calculate the dose deposited in that region. We can see the dose profile of, proton and electron, and we can see in both cases that for protons the position of delivered dose is well know, that happen in the position where the proton stop, for electrons the energies is delivered along the way and pass the desired position for high dose deposition. (author)

  20. Monte Carlo calculation of dosimetric parameters of a {sup 125}I brachytherapy seed encapsulation with biocompatible polymer and a ceramic matrix as radiographic marker

    Energy Technology Data Exchange (ETDEWEB)

    Reis, Lucas P.; Santos, Adriano M.; Grynberg, Suely E., E-mail: lpr@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil). Lab. de Dosimetria e Simulacao Computacional; Facure, Alessandro, E-mail: facure@cnen.gov.b [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    For prostate cancer treatments, there is an increasing interest in the permanent radioactive seeds implant technique. Currently, in Brazil, the seeds are imported at high prices, which prohibit their use in public hospitals. One of the seed models that have been developed at CDTN has a ceramic matrix as a radioisotope carrier and a radiographic marker; the seed is encapsulated with biocompatible polymer. In this work, Monte Carlo simulations were performed in order to assess the dose distributions generated by the prototype seed model. The obtained data was assessed as described in the TG-43U1 report by the AAPM. The dosimetric parameters dose rate constant, {Lambda}, radial dose function, g{sub L}(r), and anisotropy function, F(r,{theta}), were derived from simulations using the MCNP5 code. The function g(r) shows that the seed has a lower decrease in dose rate on its transverse axis when compared to the 6711 model (one of the most used seeds in permanent prostate implants). F(r,{theta}) shows that CDTN's seed anisotropy curves are smoother than the 6711 model curves for {theta}{<=}20 deg and 0.25{<=}r{<=}1 cm. As well, the {Lambda} value is 15% lower than the {Lambda} value of 6711. The results show that CDTN's seed model can deposit a more isotropic dose. Because of the model's characteristics, the seeds can be impregnated with iodine of lower specific activity which would help reducing costs. (author)

  1. A dosimetric comparison of 3D-CRT, IMRT, and static tomotherapy with an SIB for large and small breast volumes

    Energy Technology Data Exchange (ETDEWEB)

    Michalski, Andrea [Department of Health Science (MRS), The University of Sydney, Lidcombe, New South Wales (Australia); Central Coast Cancer Centre, Gosford Hospital, Gosford, New South Wales (Australia); Atyeo, John, E-mail: john.atyeo@sydney.edu.au [Department of Health Science (MRS), The University of Sydney, Lidcombe, New South Wales (Australia); Cox, Jennifer [Department of Health Science (MRS), The University of Sydney, Lidcombe, New South Wales (Australia); Department of Radiation Oncology, Royal North Shore Hospital, St Leonards, New South Wales (Australia); Rinks, Marianne [Department of Health Science (MRS), The University of Sydney, Lidcombe, New South Wales (Australia); Radiation Oncology, Cancer Services, Illawarra Shoalhaven Local Health District, Wollongong, New South Wales (Australia); Morgia, Marita; Lamoury, Gillian [Department of Radiation Oncology, Royal North Shore Hospital, St Leonards, New South Wales (Australia)

    2014-07-01

    Radiation therapy to the breast is a complex task, with many different techniques that can be employed to ensure adequate dose target coverage while minimizing doses to the organs at risk. This study compares the dose planning outcomes of 3 radiation treatment modalities, 3 dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and static tomotherapy, for left-sided whole-breast radiation treatment with a simultaneous integrated boost (SIB). Overall, 20 patients with left-sided breast cancer were separated into 2 cohorts, small and large, based on breast volume. Dose plans were produced for each patient using 3D-CRT, IMRT, and static tomotherapy. All patients were prescribed a dose of 45 Gy in 20 fractions to the breast with an SIB of 56 Gy in 20 fractions to the tumor bed and normalized so that D{sub 98%} > 95% of the prescription dose. Dosimetric comparisons were made between the 3 modalities and the interaction of patient size. All 3 modalities offered adequate planning target volume (PTV) coverage with D{sub 98%} > 95% and D{sub 2%} < 107%. Static tomotherapy offered significantly improved (p = 0.006) dose homogeneity to the PTV{sub boost} {sub eval} (0.079 ± 0.011) and breast minus the SIB volume (Breast{sub SIB}) (p < 0.001, 0.15 ± 0.03) compared with the PTV{sub boost} {sub eval} (0.085 ± 0.008, 0.088 ± 0.12) and Breast{sub SIB} (0.22 ± 0.05, 0.23 ± 0.03) for IMRT and 3D-CRT, respectively. Static tomotherapy also offered statistically significant reductions (p < 0.001) in doses to the ipsilateral lung mean dose of 6.79 ± 2.11 Gy compared with 7.75 ± 2.54 Gy and 8.29 ± 2.76 Gy for IMRT and 3D-CRT, respectively, and significantly (p < 0.001) reduced heart doses (mean = 2.83 ± 1.26 Gy) compared to both IMRT and 3D-CRT (mean = 3.70 ± 1.44 Gy and 3.91 ± 1.58 Gy). Static tomotherapy is the dosimetrically superior modality for the whole breast with an SIB compared with IMRT and 3D-CRT. IMRT is superior to 3D

  2. Dosimetric Characteristics of a Two-Dimensional Diode Array Detector Irradiated with Passively Scattered Proton Beams

    Energy Technology Data Exchange (ETDEWEB)

    Liengsawangwong, Praimakorn; Sahoo, Nanayan; Ding, Xiaoning; Lii, MingFwu; Gillin, Michale T.; Zhu, Xiaorong Ronald, E-mail: xrzhu@mdanderson.org [Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States)

    2015-07-30

    Purpose: To evaluate the dosimetric characteristics of a two-dimensional (2D) diode array detector irradiated with passively scattered proton beams. Materials and Methods: A diode array detector, MapCHECK (Model 1175, Sun Nuclear, Melbourne, FL, USA) was characterized in passive-scattered proton beams. The relative sensitivity of the diodes and absolute dose calibration were determined using a 250 MeV beam. The pristine Bragg curves (PBCs) measured by MapCHECK diodes were compared with those of an ion chamber using a range shift method. The water-equivalent thickness (WET) of the diode array detector’s intrinsic buildup also was determined. The inverse square dependence, linearity, and other proton dosimetric quantities measured by MapCHECK were also compared with those of the ion chambers. The change in the absolute dose response of the MapCHECK as a function of accumulated radiation dose was used as an indicator of radiation damage to the diodes. 2D dose distribution with and without the compensator were measured and compared with the treatment planning system (TPS) calculations. Results: The WET of the MapCHECK diode’s buildup was determined to be 1.7 cm. The MapCHECK-measured PBC were virtually identical to those measured by a parallel-plate ion chamber for 160, 180, and 250 MeV proton beams. The inverse square results of the MapCHECK were within ±0.4% of the ion chamber results. The linearity of MapCHECK results was within 1% of those from the ion chamber as measured in the range between 10 and 300 MU. All other dosimetric quantities were within 1.3% of the ion chamber results. The 2D dose distributions for non-clinical fields without compensator and the patient treatment fields with the compensator were consistent with the TPS results. The absolute dose response of the MapCHECK was changed by 7.4% after an accumulated dose increased by 170 Gy. Conclusions: The MapCHECK is a convenient and useful tool for 2D dose distribution measurements using passively

  3. Multi-institutional dosimetric and geometric commissioning of image-guided small animal irradiators

    Energy Technology Data Exchange (ETDEWEB)

    Lindsay, P. E., E-mail: Patricia.Lindsay@rmp.uhn.on.ca [Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 1A1 (Canada); Granton, P. V.; Hoof, S. van; Hermans, J. [Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Gasparini, A. [Department of Radiation Oncology, The Netherlands Cancer Institute, Amsterdam (Netherlands); Jelveh, S. [Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Clarkson, R. [Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 1A1 (Canada); Mid-South Radiation Physics, Inc., 1801 South 54th Street, Paragould, Arkansas 72450 (United States); Kaas, J.; Wittkamper, F.; Sonke, J.-J. [Department of Radiation Oncology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Verhaegen, F. [Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Medical Physics Unit, Department of Oncology, McGill University, Montreal, Québec H3G 1A4 (Canada); Jaffray, D. A. [Radiation Medicine Program, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9 (Canada); Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5S 1A1 (Canada); The TECHNA Institute for the Advancement of Technology for Health, Toronto, Ontario M5G 1P5 (Canada)

    2014-03-15

    Purpose: To compare the dosimetric and geometric properties of a commercial x-ray based image-guided small animal irradiation system, installed at three institutions and to establish a complete and broadly accessible commissioning procedure. Methods: The system consists of a 225 kVp x-ray tube with fixed field size collimators ranging from 1 to 44 mm equivalent diameter. The x-ray tube is mounted opposite a flat-panel imaging detector, on a C-arm gantry with 360° coplanar rotation. Each institution performed a full commissioning of their system, including half-value layer, absolute dosimetry, relative dosimetry (profiles, percent depth dose, and relative output factors), and characterization of the system geometry and mechanical flex of the x-ray tube and detector. Dosimetric measurements were made using Farmer-type ionization chambers, small volume air and liquid ionization chambers, and radiochromic film. The results between the three institutions were compared. Results: At 225 kVp, with 0.3 mm Cu added filtration, the first half value layer ranged from 0.9 to 1.0 mm Cu. The dose-rate in-air for a 40 × 40 mm{sup 2} field size, at a source-to-axis distance of 30 cm, ranged from 3.5 to 3.9 Gy/min between the three institutions. For field sizes between 2.5 mm diameter and 40 × 40 mm{sup 2}, the differences between percent depth dose curves up to depths of 3.5 cm were between 1% and 4% on average, with the maximum difference being 7%. The profiles agreed very well for fields >5 mm diameter. The relative output factors differed by up to 6% for fields larger than 10 mm diameter, but differed by up to 49% for fields ≤5 mm diameter. The mechanical characteristics of the system (source-to-axis and source-to-detector distances) were consistent between all three institutions. There were substantial differences in the flex of each system. Conclusions: With the exception of the half-value layer, and mechanical properties, there were significant differences between the

  4. Dosimetric properties of an amorphous silicon EPID for verification of modulated electron radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chatelain, Cecile; Vetterli, Daniel; Henzen, Dominik; Favre, Pascal; Fix, Michael K.; Manser, Peter [Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital and University of Bern, Bern CH-3010 (Switzerland); Morf, Daniel; Scheib, Stefan [Varian Medical Systems Imaging Laboratories GmbH, Baden-Daettwil CH-5405 (Switzerland)

    2013-06-15

    Purpose: To investigate the dosimetric properties of an electronic portal imaging device (EPID) for electron beam detection and to evaluate its potential for quality assurance (QA) of modulated electron radiotherapy (MERT). Methods: A commercially available EPID was used to detect electron beams shaped by a photon multileaf collimator (MLC) at a source-surface distance of 70 cm. The fundamental dosimetric properties such as reproducibility, dose linearity, field size response, energy response, and saturation were investigated for electron beams. A new method to acquire the flood-field for the EPID calibration was tested. For validation purpose, profiles of open fields and various MLC fields (square and irregular) were measured with a diode in water and compared to the EPID measurements. Finally, in order to use the EPID for QA of MERT delivery, a method was developed to reconstruct EPID two-dimensional (2D) dose distributions in a water-equivalent depth of 1.5 cm. Comparisons were performed with film measurement for static and dynamic monoenergy fields as well as for multienergy fields composed by several segments of different electron energies. Results: The advantageous EPID dosimetric properties already known for photons as reproducibility, linearity with dose, and dose rate were found to be identical for electron detection. The flood-field calibration method was proven to be effective and the EPID was capable to accurately reproduce the dose measured in water at 1.0 cm depth for 6 MeV, 1.3 cm for 9 MeV, and 1.5 cm for 12, 15, and 18 MeV. The deviations between the output factors measured with EPID and in water at these depths were within {+-}1.2% for all the energies with a mean deviation of 0.1%. The average gamma pass rate (criteria: 1.5%, 1.5 mm) for profile comparison between EPID and measurements in water was better than 99% for all the energies considered in this study. When comparing the reconstructed EPID 2D dose distributions at 1.5 cm depth to film

  5. Technical and dosimetric considerations in IMRT treatment planning for large target volumes.

    Science.gov (United States)

    Malhotra, Harish K; Raina, Sanjay; Avadhani, Jaiteerth S; deBoer, Steven; Podgorsak, Matthew B

    2005-01-01

    The maximum width of an intensity-modulated radiotherapy (IMRT) treatment field is usually smaller than the conventional maximum collimator opening because of design limitations inherent in some multileaf collimators (MLCs). To increase the effective field width, IMRT fluences can be split and delivered with multiple carriage positions. However, not all treatment-planning systems and MLCs support this technique, and if they do, the maximum field width in multiple carriage position delivery is still significantly less than the maximum collimator opening. For target volumes with dimensions exceeding the field size limit for multiple carriage position delivery, such as liver tumors or other malignancies in the abdominal cavity, IMRT treatment can be accomplished with multiple isocenters or with an extended treatment distance. To study dosimetric statistics of large field IMRT planning, an elliptical volume was chosen as a target within a cubic phantom centered at a depth of 7.5 cm. Multiple three-field plans (one AP and two oblique beams with 160 degrees between them to avoid parallel opposed geometry) with constraints designed to give 100% dose to the elliptical target were developed. Plans were designed with a single anterior field with dual carriage positions, or with the anterior field split into two fields with separate isocenters 8 cm apart with the beams being forcibly matched at the isocenter or with a 1 cm, 2 cm, 3 cm, and 4 cm overlap. The oblique beams were planned with a single carriage position in all cases. All beams had a nominal energy of 6 MV. In the dual isocenter plans, jaws were manually fixed and dose constraints remained unaltered. Dosimetric statistics were studied for plans developed for treatment delivery using both dynamic leaf motion (sliding window) and multiple static segments (step and shoot) with the number of segments varying from 5 to 30. All plans were analyzed based on the dose homogeneity in the isocenter plane, 2 cm anterior and 2

  6. Dosimetric analysis of 123I, 125I and 131I in thyroid follicle models

    Science.gov (United States)

    2014-01-01

    Background Radioiodine is routinely used or proposed for diagnostic and therapeutic purposes: 123I, 125I and 131I for diagnostics and 125I and 131I for therapy. When radioiodine-labelled pharmaceuticals are administered to the body, radioiodide might be released into the circulation and taken up by the thyroid gland, which may then be an organ at risk. The aim of this study was to compare dosimetric properties for 123I, 125I and 131I in previously developed thyroid models for man, rat and mouse. Methods Dosimetric calculations were performed using the Monte Carlo code MCNPX 2.6.0 and nuclear decay data from ICRP 107. Only the non-radiative transitions in the decays were considered. The S value was determined for the cell nuclei in species-specific thyroid follicle models for mouse, rat and man for different spatial distributions of radioiodine. Results For the species-specific single follicle models with radioiodine homogeneously within the follicle lumen, the highest S value came from 131I, with the largest contribution from the β particles. When radioiodine was homogeneously distributed within the follicle cells or the follicle cell nucleus, the highest contribution originated from 125I, about two times higher than 123I, with the largest contribution from the Auger electrons. The mean absorbed dose calculated for our human thyroid multiple follicle model, assuming homogenous distribution of for 123I, 125I, or 131I within the follicle lumens and follicle cells, was 9%, 18% and 4% higher, respectively, compared with the mean absorbed dose according to Medical Internal Radiation Dose (MIRD) formalism and nuclear decay data. When radioiodine was homogeneously distributed in the follicle lumens, our calculations gave up to 90% lower mean absorbed dose for 125I compared to MIRD (20% lower for 123I, and 2% lower for 131I). Conclusions This study clearly demonstrates the importance of using more detailed dosimetric methods and models than MIRD formalism for radioiodine

  7. Monte Carlo derivation of AAPM TG-43 dosimetric parameters for GZP6 Co-60 HDR sources.

    Science.gov (United States)

    Tabrizi, Sanaz Hariri; Asl, Alireza Kamali; Azma, Zohreh

    2012-04-01

    Cobalt 60 source is generally available on high dose rate (HDR) afterloading equipment especially for treatment of gynecological lesions. The GZP6 remote afterloader (Nuclear Power Institute of China) utilizes (60)Co sources for treatment of intracavitary and intraluminal malignancies. In this study, the AAPM TG-43 dosimetric parameters of three sources in GZP6 system have been studied using MCNP4C Monte Carlo (MC) code; and the results are compared with other available (60)Co HDR sources. The presented parameters consist of air kerma strength, dose rate constant, radial dose function and anisotropy function. They show less than 1% uncertainty. The TG-43 based dosimetry data can be used not only to validate the dedicated treatment planning software (TPS), but also to introduce new complementary software to enhance the system performance in gynecological treatments.

  8. Dosimetric response for crystalline and nanostructured aluminium oxide to a high-current pulse electron beam.

    Science.gov (United States)

    Nikiforov, S V; Kortov, V S

    2014-11-01

    The main thermoluminescent (TL) and dosimetric properties of the detectors based on anion-defective crystalline and nanostructured aluminium oxide after exposure to a high-current pulse electron beam are studied. TL peaks associated with deep-trapping centres are registered. It is shown that the use of deep-trap TL at 200-600°С allows registering absorbed doses up to 750 kGy for single-crystalline detectors and those up to 6 kGy for nanostructured ones. A wide range of the doses registered, high reproducibility of the TL signal and low fading contribute to a possibility of using single-crystalline and nanostructured aluminium oxide for the dosimetry of high-current pulse electron beams.

  9. Dosimetric and spectrometric neutron measurements around an annular vessel containing a plutonium nitrate fissile solution

    Energy Technology Data Exchange (ETDEWEB)

    Tournier, B.; Itie, C.; Medioni, R. E-mail: roger.medioni@ipsn.fr; Rich, C.; Mussoni, F.; Camus, L.; Pichenot, G.; Crovisier, Ph.; Cutarella, D.; Asselineau, B.; Groetz, J.E

    2002-01-01

    The new ICPR60 recommendations and the consideration of the ALARA principle have led the operators of nuclear facilities to evaluate with a higher care, the doses received by workers. The aim of this paper is to present a recent study concerning mixed field characterisation at a workplace located in a reprocessing laboratory. As a first step, neutron spectrum determination was achieved by two ways: simulation using MCNP code and experimental measurements with Bonner spheres and recoil proton counters. Neutron spectrum allowed the evaluation of dosimetric quantities. Measurements were then performed with different devices routinely used in radioprotection. The authors describe the measurement techniques, present the results obtained, and finally compare and discuss them.

  10. Dosimetric Evaluation of Individualized Adaptive Motion Margins for Abdominal and Thoracic Tumors

    DEFF Research Database (Denmark)

    Poulsen, Per Rugaard; Cho, Byungchul; Keall, Paul

    Purpose/Objective(s): In motion inclusive radiotherapy, respiratory tumor motion is normally accounted for either by population-based CTV-PTV margins that are parallel to the room coordinate system, or by introduction of an ITV that encompasses the tumor motion in a planning CT scan. While...... the former ignores motion correlation along different axes the latter tends to overestimate the dosimetric consequences of random motion. The purpose of this study was to propose and investigate an individualized adaptive margin approach that accounts for motion correlation while still considering...... minutes: First, a cone-beam CT (CBCT) scan with 600 projections was acquired in 1 minute. The tumor position in the CBCT projections was used to estimate the mean position and covariance matrix of the tumor motion (i.e., tumor motion magnitude and tumor motion axes) during the CBCT acquisition. Next...

  11. Investigation of pulsed IMRT and VMAT for re-irradiation treatments: dosimetric and delivery feasibilities

    Science.gov (United States)

    Lin, Mu-Han; Price, Robert A., Jr.; Li, Jinsheng; Kang, Shengwei; Li, Jie; Ma, C.-M.

    2013-11-01

    Many tumor cells demonstrate hyperradiosensitivity at doses below ˜50 cGy. Together with the increased normal tissue repair under low dose rate, the pulsed low dose rate radiotherapy (PLDR), which separates a daily fractional dose of 200 cGy into 10 pulses with 3 min interval between pulses (˜20 cGy/pulse and effective dose rate 6.7 cGy min-1), potentially reduces late normal tissue toxicity while still providing significant tumor control for re-irradiation treatments. This work investigates the dosimetric and technical feasibilities of intensity modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT)-based PLDR treatments using Varian Linacs. Twenty one cases (12 real re-irradiation cases) including treatment sites of pancreas, prostate, pelvis, lung, head-and-neck, and breast were recruited for this study. The lowest machine operation dose rate (100 MU min-1) was employed in the plan delivery. Ten-field step-and-shoot IMRT and dual-arc VMAT plans were generated using the Eclipse TPS with routine planning strategies. The dual-arc plans were delivered five times to achieve a 200 cGy daily dose (˜20 cGy arc-1). The resulting plan quality was evaluated according to the heterogeneity and conformity indexes (HI and CI) of the planning target volume (PTV). The dosimetric feasibility of retaining the hyperradiosensitivity for PLDR was assessed based on the minimum and maximum dose in the target volume from each pulse. The delivery accuracy of VMAT and IMRT at the 100 MU min-1 machine operation dose rate was verified using a 2D diode array and ion chamber measurements. The delivery reproducibility was further investigated by analyzing the Dynalog files of repeated deliveries. A comparable plan quality was achieved by the IMRT (CI 1.10-1.38 HI 1.04-1.10) and the VMAT (CI 1.08-1.26 HI 1.05-1.10) techniques. The minimum/maximum PTV dose per pulse is 7.9 ± 5.1 cGy/33.7 ± 6.9 cGy for the IMRT and 12.3 ± 4.1 cGy/29.2 ± 4.7 cGy for the VMAT. Six out of

  12. The dosimetric significance of using 10 MV photons for volumetric modulated arc therapy for post-prostatectomy irradiation of the prostate bed

    Directory of Open Access Journals (Sweden)

    Kleiner Henry

    2016-06-01

    Full Text Available The purpose of the study was to analyse the dosimetric differences when using 10 MV instead of 6 MV for VMAT treatment plans for post-prostatectomy irradiation of the prostate bed.

  13. Evaluation of the dosimetric impact of applying flattening filter-free beams in intensity-modulated radiotherapy for early-stage upper thoracic carcinoma of oesophagus

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wuzhe; Lin, Zhixiong; Yang, Zhining; Fang, Weisheng; Lai, Peibo; Lu, Jiayang [Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong (China); Wu, Vincent WC, E-mail: vincent.wu@polyu.edu.hk [Department of Health Technology and Informatics, Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Department of Radiation Oncology, Cancer Hospital of Shantou University Medical College, Shantou, Guangdong (China)

    2015-06-15

    Flattening filter-free (FFF) radiation beams have recently become clinically available on modern linear accelerators in radiation therapy. This study aimed to evaluate the dosimetric impact of using FFF beams in intensity-modulated radiotherapy (IMRT) for early-stage upper thoracic oesophageal cancer. Eleven patients with primary stage upper thoracic oesophageal cancer were recruited. For each patient, two IMRT plans were computed using conventional beams (Con-P) and FFF beams (FFF-P), respectively. Both plans employed a five-beam arrangement and were prescribed with 64 Gy to (planning target volume) PTV1 and 54 Gy to PTV2 in 32 fractions using 6 MV photons. The dose parameters of the target volumes and organs at risks (OARs), and treatment parameters including the monitor units (MU) and treatment time (TT) for Con-P and FFF-P were recorded and compared. The mean D{sub 5} of PTV1 and PTV2 were higher in FFF-P than Con-P by 0.4 Gy and 0.3 Gy, respectively. For the OARs, all the dose parameters did not show significant difference between the two plans except the mean V{sub 5} and V{sub 10} of the lung in which the FFF-P was lower (46.7% vs. 47.3% and 39.1% vs. 39.6%, respectively). FFF-P required 54% more MU but 18.4% less irradiation time when compared to Con-P. The target volume and OARs dose distributions between the two plans were comparable. However, FFF-P was more effective in sparing the lung from low dose and reduced the mean TT compared with Con-P. Long-term clinical studies are suggested to evaluate the radiobiological effects of FFF beams.

  14. SU-E-J-151: Dosimetric Evaluation of DIR Mapped Contours for Image Guided Adaptive Radiotherapy with 4D Cone-Beam CT

    Energy Technology Data Exchange (ETDEWEB)

    Balik, S [Cleveland Clinic Foundation, Cleveland, OH (United States); Weiss, E; Williamson, J; Hugo, G [Virginia Commonwealth University, Richmond, VA (United States); Jan, N; Zhang, L [Virginia Commonwealth University, Richmond, Virginia (United States); Roman, N [San Antonio Precision Center Ctr, San Antonio, TX (United States); Christensen, G [University of Iowa, Iowa City, IA (United States)

    2014-06-01

    Purpose: To estimate dosimetric errors resulting from using contours deformably mapped from planning CT to 4D cone beam CT (CBCT) images for image-guided adaptive radiotherapy of locally advanced non-small cell lung cancer (NSCLC). Methods: Ten locally advanced non-small cell lung cancer (NSCLC) patients underwent one planning 4D fan-beam CT (4DFBCT) and weekly 4DCBCT scans. Multiple physicians delineated the gross tumor volume (GTV) and normal structures in planning CT images and only GTV in CBCT images. Manual contours were mapped from planning CT to CBCTs using small deformation, inverse consistent linear elastic (SICLE) algorithm for two scans in each patient. Two physicians reviewed and rated the DIR-mapped (auto) and manual GTV contours as clinically acceptable (CA), clinically acceptable after minor modification (CAMM) and unacceptable (CU). Mapped normal structures were visually inspected and corrected if necessary, and used to override tissue density for dose calculation. CTV (6mm expansion of GTV) and PTV (5mm expansion of CTV) were created. VMAT plans were generated using the DIR-mapped contours to deliver 66 Gy in 33 fractions with 95% and 100% coverage (V66) to PTV and CTV, respectively. Plan evaluation for V66 was based on manual PTV and CTV contours. Results: Mean PTV V66 was 84% (range 75% – 95%) and mean CTV V66 was 97% (range 93% – 100%) for CAMM scored plans (12 plans); and was 90% (range 80% – 95%) and 99% (range 95% – 100%) for CA scored plans (7 plans). The difference in V66 between CAMM and CA was significant for PTV (p = 0.03) and approached significance for CTV (p = 0.07). Conclusion: The quality of DIR-mapped contours directly impacted the plan quality for 4DCBCT-based adaptation. Larger safety margins may be needed when planning with auto contours for IGART with 4DCBCT images. Reseach was supported by NIH P01CA116602.

  15. SU-C-213-06: Dosimetric Verification of 3D Printed Electron Bolus

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, K; Corbett, M; Pelletier, C; Huang, Z; Feng, Y; Jung, J [East Carolina Univ, Greenville, NC (United States)

    2015-06-15

    Purpose: To determine the dosimetric effect of 3D printed bolus in an anthropomorphic phantom. Methods: Conformable bolus material was generated for an anthropomorphic phantom from a DICOM volume. The bolus generated was a uniform expansion of 5mm applied to the nose region of the phantom, as this is a difficult area to uniformly apply bolus clinically. A Printrbot metal 3D Printer using PLA plastic generated the bolus. A 9MeV anterior beam with a 5cm cone was used to deliver dose to the nose of the phantom. TLD measurements were compared to predicted values at the phantom surface. Film planes were analyzed for the printed bolus, a standard 5mm bolus sheet placed on the phantom, and the phantom with no bolus applied to determine depth and dose distributions. Results: TLDs measured within 2.5% of predicted value for the 3D bolus. Film demonstrated a more uniform dose distribution in the nostril region for the 3d printed bolus than the standard bolus. This difference is caused by the air gap created around the nostrils by the standard bolus, creating a secondary build-up region. Both demonstrated a 50% central axis dose shift of 5mm relative to the no bolus film. HU for the bolus calculated the PLA electron density to be ∼1.1g/cc. Physical density was measured to be 1.3g/cc overall. Conclusion: 3D printed PLA bolus demonstrates improved dosimetric performance to standard bolus for electron beams with complex phantom geometry.

  16. Predicting Nonauditory Adverse Radiation Effects Following Radiosurgery for Vestibular Schwannoma: A Volume and Dosimetric Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hayhurst, Caroline; Monsalves, Eric; Bernstein, Mark; Gentili, Fred [Gamma Knife Unit, Division of Neurosurgery, University Health Network, Toronto (Canada); Heydarian, Mostafa; Tsao, May [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); Schwartz, Michael [Radiation Oncology Program and Division of Neurosurgery, Sunnybrook Hospital, Toronto (Canada); Prooijen, Monique van [Radiation Medicine Program, Princess Margaret Hospital, Toronto (Canada); Millar, Barbara-Ann; Menard, Cynthia [Radiation Oncology Program, Princess Margaret Hospital, Toronto (Canada); Kulkarni, Abhaya V. [Division of Neurosurgery, Hospital for Sick Children, University of Toronto (Canada); Laperriere, Norm [Radiation Oncology Program, Princess Margaret Hospital, Toronto (Canada); Zadeh, Gelareh, E-mail: Gelareh.Zadeh@uhn.on.ca [Gamma Knife Unit, Division of Neurosurgery, University Health Network, Toronto (Canada)

    2012-04-01

    Purpose: To define clinical and dosimetric predictors of nonauditory adverse radiation effects after radiosurgery for vestibular schwannoma treated with a 12 Gy prescription dose. Methods: We retrospectively reviewed our experience of vestibular schwannoma patients treated between September 2005 and December 2009. Two hundred patients were treated at a 12 Gy prescription dose; 80 had complete clinical and radiological follow-up for at least 24 months (median, 28.5 months). All treatment plans were reviewed for target volume and dosimetry characteristics; gradient index; homogeneity index, defined as the maximum dose in the treatment volume divided by the prescription dose; conformity index; brainstem; and trigeminal nerve dose. All adverse radiation effects (ARE) were recorded. Because the intent of our study was to focus on the nonauditory adverse effects, hearing outcome was not evaluated in this study. Results: Twenty-seven (33.8%) patients developed ARE, 5 (6%) developed hydrocephalus, 10 (12.5%) reported new ataxia, 17 (21%) developed trigeminal dysfunction, 3 (3.75%) had facial weakness, and 1 patient developed hemifacial spasm. The development of edema within the pons was significantly associated with ARE (p = 0.001). On multivariate analysis, only target volume is a significant predictor of ARE (p = 0.001). There is a target volume threshold of 5 cm3, above which ARE are more likely. The treatment plan dosimetric characteristics are not associated with ARE, although the maximum dose to the 5th nerve is a significant predictor of trigeminal dysfunction, with a threshold of 9 Gy. The overall 2-year tumor control rate was 96%. Conclusions: Target volume is the most important predictor of adverse radiation effects, and we identified the significant treatment volume threshold to be 5 cm3. We also established through our series that the maximum tolerable dose to the 5th nerve is 9 Gy.

  17. Monte Carlo investigation of the dosimetric effect of the Autoscan ultrasound probe for guidance in radiotherapy

    Science.gov (United States)

    Martyn, Michael; O'Shea, Tuathan; Harris, Emma; Bamber, Jeffrey; Gilroy, Stephen; Foley, Mark J.

    2016-04-01

    The aim of this study was to quantify the dosimetric effect of the Autoscan™ ultrasound probe, which is a 3D transperineal probe used for real-time tissue tracking during the delivery of radiotherapy. CT images of an anthropomorphic phantom, with and without the probe placed in contact with its surface, were obtained (0.75 mm slice width, 140 kVp). CT datasets were used for relative dose calculation in Monte Carlo simulations of a 7-field plan delivered to the phantom. The Monte Carlo software packages BEAMnrc and DOSXYZnrc were used for this purpose. A number of simulations, which varied the distance of the radiation field edge from the probe face (0 mm to 5 mm), were performed. Perineal surface doses as a function of distance from the radiation field edge, with and without the probe in place, were compared. The presence of the probe was found to result in an increase in perineal surface dose, relative to the maximum dose. The maximum increase in surface dose was 18.15%, at a probe face to field edge distance of 0 mm. However increases in surface dose fall-off rapidly as this distance increases, agreeing within Monte Carlo simulation uncertainty at distances >= 5 mm. Using data from three patient volunteers, a typical probe face to field edge distance was calculated to be ≍20 mm. Our results therefore indicate that the presence of the probe is unlikely to adversely affect a typical patient treatment, since the dosimetric effect of the probe is minimal at these distances.

  18. Evaluation of specific absorption rate as a dosimetric quantity for electromagnetic fields bioeffects.

    Directory of Open Access Journals (Sweden)

    Dimitris J Panagopoulos

    Full Text Available PURPOSE: To evaluate SAR as a dosimetric quantity for EMF bioeffects, and identify ways for increasing the precision in EMF dosimetry and bioactivity assessment. METHODS: We discuss the interaction of man-made electromagnetic waves with biological matter and calculate the energy transferred to a single free ion within a cell. We analyze the physics and biology of SAR and evaluate the methods of its estimation. We discuss the experimentally observed non-linearity between electromagnetic exposure and biological effect. RESULTS: WE FIND THAT: a The energy absorbed by living matter during exposure to environmentally accounted EMFs is normally well below the thermal level. b All existing methods for SAR estimation, especially those based upon tissue conductivity and internal electric field, have serious deficiencies. c The only method to estimate SAR without large error is by measuring temperature increases within biological tissue, which normally are negligible for environmental EMF intensities, and thus cannot be measured. CONCLUSIONS: SAR actually refers to thermal effects, while the vast majority of the recorded biological effects from man-made non-ionizing environmental radiation are non-thermal. Even if SAR could be accurately estimated for a whole tissue, organ, or body, the biological/health effect is determined by tiny amounts of energy/power absorbed by specific biomolecules, which cannot be calculated. Moreover, it depends upon field parameters not taken into account in SAR calculation. Thus, SAR should not be used as the primary dosimetric quantity, but used only as a complementary measure, always reporting the estimating method and the corresponding error. Radiation/field intensity along with additional physical parameters (such as frequency, modulation etc which can be directly and in any case more accurately measured on the surface of biological tissues, should constitute the primary measure for EMF exposures, in spite of similar

  19. Daily dosimetric quality control of the MM50 Racetrack Microtron using an electronic portal imaging device.

    Science.gov (United States)

    Dirkx, M L; Kroonwijk, M; de Boer, J C; Heijmen, B J

    1995-10-01

    The MM50 Racetrack Microtron, suited for advanced three-dimensional conformal radiotherapy techniques, is a complex machine in various respects. Therefore, for a number of gantry angles, daily quality control of the absolute output and fluence profiles of the scanned beams are mandatory. For the applied photon beams, a fast method for these daily checks, based on dosimetric measurements with the Philips SRI-100 Electronic Portal Imaging Device (EPID), has been developed and tested. Open beams are checked for four different gantry angles; for gantry angle 0, a wedged field is checked as well. Performing and analyzing the measurements takes about 10 min. The applied EPID has favourable characteristics for dosimetric quality control measurements: absolute output measurements reproduce within 0.5% (1 SD) and the reproducibility of relative (2D) beam profile measurements is 0.2% (1 SD). The day-to-day sensitivity stability over a period of one month is 0.6% (1 SD). Measured grey scale values are within 0.2% linear with the applied dose. The 2D fluence profile of the 25 MV photon beam of the MM50 is very stable in time: during a period of 5 months a maximum fluctuation of 2.2% has been observed. Once, a deviation in the cGy/MU-value of 6% was detected. There is no interlock in the MM50-system that would have prevented patient treatment with this strongly deviating output. Based on the results of this study and on clinical requirements regarding acceptability of deviations of beam characteristics, a protocol has been developed including action levels for additional investigations and, if necessary, adjustment of the beam characteristics.

  20. Physical, morphological and dosimetric characterization of the Teflon agglutinator to thermoluminescent dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    D' Amorim, R.A.P.O., E-mail: raquelalinepe@gmail.com [Departamento de Física-CCET, Universidade Federal de Sergipe, 49100-000 São Cristóvão, SE (Brazil); Teixeira, M.I., E-mail: miteixeira@ipen.br [Instituto de Pesquisas Energéticas e Nucleares-IPEN-CNEN/SP, Av. Professor Lineu Prestes, 2242, 05508-000 São Paulo (Brazil); Caldas, L.V.E., E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energéticas e Nucleares-IPEN-CNEN/SP, Av. Professor Lineu Prestes, 2242, 05508-000 São Paulo (Brazil); Souza, S.O., E-mail: susanasouzalalic@gmail.com [Departamento de Física-CCET, Universidade Federal de Sergipe, 49100-000 São Cristóvão, SE (Brazil)

    2013-04-15

    In preparing of thermoluminescent dosimeters (TLD) it is common to use as agglutinator the polytetrafluoroethylene (PTFE), called Teflon{sup ®}. In this paper the physical, morphological and dosimetric characteristics of Teflon{sup ®} were evaluated aiming its application in thermoluminescent dosimetry. The differential thermal analysis (DTA) and thermogravimetry (TG) results showed that the Teflon glass transition and melting points are of about 48 °C and 340 °C, respectively. By means of the X-ray diffraction technique, the crystallinity index K{sub c} was estimated as 94%. Micrographs of Scanning Electron Microscopy (SEM) showed a cohesive surface in spodumene–Teflon pellets, as required for thermoluminescent dosimeters (TLD), leading to the conclusion that Teflon acts as binder, providing greater mechanical resistance to the TL pellets. However, Teflon may influence high doses dosimetry when it is applied as an agglutinator. Preliminary results of Teflon pellets dosimetric properties, with their dose–response curve between 50 Gy and 60 kGy, TL response reproducibility and minimum detectable dose, indicate the possibility of use of pure Teflon TLD in high-dose dosimetry. -- Highlights: ► Pure Teflon{sup ®} pellets can be exploited for high-dose dosimetry. ► Pure Teflon{sup ®} pellets showed two TL peaks. ► Low dose limits of Teflon{sup ®} pellets were 7.0 and 4.0 Gy for the first and second TL peaks respectively. ► The reproducibility of TL response of Teflon{sup ®} pellets is 2.9%.

  1. Gamma Knife irradiation method based on dosimetric controls to target small areas in rat brains

    Energy Technology Data Exchange (ETDEWEB)

    Constanzo, Julie; Paquette, Benoit; Charest, Gabriel [Center for Radiotherapy Research, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001 12th Avenue Nord, Sherbrooke, Québec J1H 5N4 (Canada); Masson-Côté, Laurence; Guillot, Mathieu, E-mail: mathieu.guillot@usherbrooke.ca [Department of Radiation Oncology, Centre Hospitalier Universitaire de Sherbrooke, 3001 12th Avenue Nord, Sherbrooke, Québec J1H 5N4, Canada and Center for Radiotherapy Research, Department of Nuclear Medicine and Radiobiology, Université de Sherbrooke, 3001 12th Avenue Nord, Sherbrooke, Québec J1H 5N4 (Canada)

    2015-05-15

    Purpose: Targeted and whole-brain irradiation in humans can result in significant side effects causing decreased patient quality of life. To adequately investigate structural and functional alterations after stereotactic radiosurgery, preclinical studies are needed. The purpose of this work is to establish a robust standardized method of targeted irradiation on small regions of the rat brain. Methods: Euthanized male Fischer rats were imaged in a stereotactic bed, by computed tomography (CT), to estimate positioning variations relative to the bregma skull reference point. Using a rat brain atlas and the stereotactic bregma coordinates obtained from CT images, different regions of the brain were delimited and a treatment plan was generated. A single isocenter treatment plan delivering ≥100 Gy in 100% of the target volume was produced by Leksell GammaPlan using the 4 mm diameter collimator of sectors 4, 5, 7, and 8 of the Gamma Knife unit. Impact of positioning deviations of the rat brain on dose deposition was simulated by GammaPlan and validated with dosimetric measurements. Results: The authors’ results showed that 90% of the target volume received 100 ± 8 Gy and the maximum of deposited dose was 125 ± 0.7 Gy, which corresponds to an excellent relative standard deviation of 0.6%. This dose deposition calculated with GammaPlan was validated with dosimetric films resulting in a dose-profile agreement within 5%, both in X- and Z-axes. Conclusions: The authors’ results demonstrate the feasibility of standardizing the irradiation procedure of a small volume in the rat brain using a Gamma Knife.

  2. Epigenetic Regulation of KLHL34 Predictive of Pathologic Response to Preoperative Chemoradiation Therapy in Rectal Cancer Patients

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Ye J. [Department of Surgery, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Institute of Innovative Cancer Research and Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Kim, Chan W. [Department of Surgery, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Roh, Seon A. [Department of Surgery, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Institute of Innovative Cancer Research and Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Cho, Dong H. [Institute of Innovative Cancer Research and Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Graduate School of East-West Medical Science, Kyung Hee University, Gyeonggi-do (Korea, Republic of); Park, Jong L.; Kim, Seon Y. [Medical Genomics Research Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon (Korea, Republic of); Kim, Jong H. [Department of Radiation Oncology, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Choi, Eun K. [Department of Radiation Oncology, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Institute of Innovative Cancer Research and Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Kim, Yong S., E-mail: yongsung@kribb.re.kr [Medical Genomics Research Center, Korea Research Institute of Bioscience & Biotechnology, Daejeon (Korea, Republic of); Institute of Innovative Cancer Research and Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of); Kim, Jin C., E-mail: jckim@amc.seoul.kr [Department of Surgery, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Institute of Innovative Cancer Research and Asan Institute for Life Sciences, Asan Medical Center, Seoul (Korea, Republic of)

    2015-03-01

    Purpose: Prediction of individual responsiveness to preoperative chemoradiation therapy (CRT) is urgently needed in patients with poorly responsive locally advanced rectal cancer (LARC). Methods and Materials: Candidate methylation genes associated with radiosensitivity were identified using a 3-step process. In the first step, genome-wide screening of methylation genes was performed in correlation with histopathologic tumor regression grade in 45 patients with LARC. In the second step, the methylation status of selected sites was analyzed by pyrosequencing in 67 LARC patients, including 24 patients analyzed in the first step. Finally, colorectal <