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Sample records for 3-dimensional conformal radiation

  1. 3-dimensional conformal radiation therapy plus arterial infusion chemotherapy for locally advanced pancreatic cancer

    Objective: To improve the therapeutic response and survival of locally advanced pancreatic cancer treated with radiochemotherapy. Methods: Fifty-nine patients with stage II-III pancreatic cancer were divided into two groups: 33 patients were treated with three-dimensional conformed radiotherapy (3DCRT) plus regional intra-arterial infusion chemotherapy (CT) and 26 patients received 3DCRT alone. Results: The response (pain-alleviating) rates were 78.8% in 3DCRT + CT group and 80.8% in 3DCRT group, while the overall response (CR + PR) rates were 78.8% and 42.3% (P < 0.01), respectively. The 1-, 2-, 3-year survival rates were 72.2%, 48.5%, 9.1% and 50.0%, 15.4%, 3.9%, with the difference in the 2-year survival between these two groups statistically significant (P < 0.01). Conclusions: Three dimensional conformal radiation therapy combined with regional intra-arterial infusion chemotherapy is an effective treatment for unresectable locally advanced pancreatic cancer

  2. Potential for Improved Intelligence Quotient Using Volumetric Modulated Arc Therapy Compared With Conventional 3-Dimensional Conformal Radiation for Whole-Ventricular Radiation in Children

    Purpose: To compare volumetric modulated arc therapy (VMAT) with 3-dimensional conformal radiation therapy (3D-CRT) in the treatment of localized intracranial germinoma. We modeled the effect of the dosimetric differences on intelligence quotient (IQ). Method and Materials: Ten children with intracranial germinomas were used for planning. The prescription doses were 23.4 Gy to the ventricles followed by 21.6 Gy to the tumor located in the pineal region. For each child, a 3D-CRT and full arc VMAT was generated. Coverage of the target was assessed by computing a conformity index and heterogeneity index. We also generated VMAT plans with explicit temporal lobe sparing and with smaller ventricular margin expansions. Mean dose to the temporal lobe was used to estimate IQ 5 years after completion of radiation, using a patient age of 10 years. Results: Compared with the 3D-CRT plan, VMAT improved conformality (conformity index 1.10 vs 1.85), with slightly higher heterogeneity (heterogeneity index 1.09 vs 1.06). The averaged mean doses for left and right temporal lobes were 31.3 and 31.7 Gy, respectively, for VMAT plans and 37.7 and 37.6 Gy for 3D-CRT plans. This difference in mean temporal lobe dose resulted in an estimated IQ difference of 3.1 points at 5 years after radiation therapy. When the temporal lobes were explicitly included in the VMAT optimization, the mean temporal lobe dose was reduced 5.6-5.7 Gy, resulting in an estimated IQ difference of an additional 3 points. Reducing the ventricular margin from 1.5 cm to 0.5 cm decreased mean temporal lobe dose 11.4-13.1 Gy, corresponding to an estimated increase in IQ of 7 points. Conclusion: For treatment of children with intracranial pure germinomas, VMAT compared with 3D-CRT provides increased conformality and reduces doses to normal tissue. This may result in improvements in IQ in these children.

  3. Two-Year and Lifetime Cost-Effectiveness of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Head-and-Neck Cancer

    Purpose: To assess the cost-effectiveness of intensity modulated radiation therapy (IMRT) versus 3-dimensional conformal radiation therapy (3D-CRT) in the treatment of head-and neck-cancer (HNC). Methods and Materials: We used a Markov model to simulate radiation therapy-induced xerostomia and dysphagia in a hypothetical cohort of 65-year-old HNC patients. Model input parameters were derived from PARSPORT (CRUK/03/005) patient-level trial data and quality-of-life and Medicare cost data from published literature. We calculated average incremental cost-effectiveness ratios (ICERs) from the US health care perspective as cost per quality-adjusted life-year (QALY) gained and compared our ICERs with current cost-effectiveness standards whereby treatment comparators less than $50,000 per QALY gained are considered cost-effective. Results: In the first 2 years after initial treatment, IMRT is not cost-effective compared with 3D-CRT, given an average ICER of $101,100 per QALY gained. However, over 15 years (remaining lifetime on the basis of average life expectancy of a 65-year-old), IMRT is more cost-effective at $34,523 per QALY gained. Conclusion: Although HNC patients receiving IMRT will likely experience reduced xerostomia and dysphagia symptoms, the small quality-of-life benefit associated with IMRT is not cost-effective in the short term but may be cost-effective over a patient's lifetime, assuming benefits persist over time and patients are healthy and likely to live for a sustained period. Additional data quantifying the long-term benefits of IMRT, however, are needed

  4. Two-Year and Lifetime Cost-Effectiveness of Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy for Head-and-Neck Cancer

    Kohler, Racquel E. [Department of Health Policy and Management, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Sheets, Nathan C. [Department of Radiation Oncology, University of North Carolina Hospitals, Chapel Hill, North Carolina (United States); Wheeler, Stephanie B. [Department of Health Policy and Management, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina (United States); Nutting, Chris [Royal Marsden Hospital, London, United Kindom (United Kingdom); Hall, Emma [Clinical Trials and Statistics Unit, Division of Clinical Studies, Institute of Cancer Research, London (United Kingdom); Chera, Bhishamjit S., E-mail: bchera@med.unc.edu [Department of Radiation Oncology, University of North Carolina Hospitals, Chapel Hill, North Carolina (United States)

    2013-11-15

    Purpose: To assess the cost-effectiveness of intensity modulated radiation therapy (IMRT) versus 3-dimensional conformal radiation therapy (3D-CRT) in the treatment of head-and neck-cancer (HNC). Methods and Materials: We used a Markov model to simulate radiation therapy-induced xerostomia and dysphagia in a hypothetical cohort of 65-year-old HNC patients. Model input parameters were derived from PARSPORT (CRUK/03/005) patient-level trial data and quality-of-life and Medicare cost data from published literature. We calculated average incremental cost-effectiveness ratios (ICERs) from the US health care perspective as cost per quality-adjusted life-year (QALY) gained and compared our ICERs with current cost-effectiveness standards whereby treatment comparators less than $50,000 per QALY gained are considered cost-effective. Results: In the first 2 years after initial treatment, IMRT is not cost-effective compared with 3D-CRT, given an average ICER of $101,100 per QALY gained. However, over 15 years (remaining lifetime on the basis of average life expectancy of a 65-year-old), IMRT is more cost-effective at $34,523 per QALY gained. Conclusion: Although HNC patients receiving IMRT will likely experience reduced xerostomia and dysphagia symptoms, the small quality-of-life benefit associated with IMRT is not cost-effective in the short term but may be cost-effective over a patient's lifetime, assuming benefits persist over time and patients are healthy and likely to live for a sustained period. Additional data quantifying the long-term benefits of IMRT, however, are needed.

  5. Accuracy of Real-time Couch Tracking During 3-dimensional Conformal Radiation Therapy, Intensity Modulated Radiation Therapy, and Volumetric Modulated Arc Therapy for Prostate Cancer

    Purpose: To evaluate the accuracy of real-time couch tracking for prostate cancer. Methods and Materials: Intrafractional motion trajectories of 15 prostate cancer patients were the basis for this phantom study; prostate motion had been monitored with the Calypso System. An industrial robot moved a phantom along these trajectories, motion was detected via an infrared camera system, and the robotic HexaPOD couch was used for real-time counter-steering. Residual phantom motion during real-time tracking was measured with the infrared camera system. Film dosimetry was performed during delivery of 3-dimensional conformal radiation therapy (3D-CRT), step-and-shoot intensity modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT). Results: Motion of the prostate was largest in the anterior–posterior direction, with systematic (∑) and random (σ) errors of 2.3 mm and 2.9 mm, respectively; the prostate was outside a threshold of 5 mm (3D vector) for 25.0%±19.8% of treatment time. Real-time tracking reduced prostate motion to ∑=0.01 mm and σ = 0.55 mm in the anterior–posterior direction; the prostate remained within a 1-mm and 5-mm threshold for 93.9%±4.6% and 99.7%±0.4% of the time, respectively. Without real-time tracking, pass rates based on a γ index of 2%/2 mm in film dosimetry ranged between 66% and 72% for 3D-CRT, IMRT, and VMAT, on average. Real-time tracking increased pass rates to minimum 98% on average for 3D-CRT, IMRT, and VMAT. Conclusions: Real-time couch tracking resulted in submillimeter accuracy for prostate cancer, which transferred into high dosimetric accuracy independently of whether 3D-CRT, IMRT, or VMAT was used.

  6. The treatment of nonpalpable PSA-detected adenocarcinoma of the prostate with 3-dimensional conformal radiation therapy

    Purpose: We reviewed our institution's experience treating patients with nonpalpable PSA-detected prostate cancer with three-dimensional conformal radiation therapy (3DCRT) to determine prognostic factors that predict for biochemical-free survival (bNED) control and present the bNED control rates. Methods and Materials: Between May 1, 1990 and November 30, 1994, 160 patients with nonpalpable PSA-detected prostate cancer received 3DCRT at Fox Chase Cancer Center (median total dose 73 Gy; range: 67-78 Gy). bNED failure was defined as three consecutive increases in posttreatment PSA after achieving a nadir. bNED failure was recorded as the time midway between the nadir and the first consecutive rising PSA. Five-year actuarial rates of bNED control were calculated for pretreatment PSA (0-9.9 vs. 10-19.9 vs. ≥ 20 ng/ml), Gleason score (2-6 vs. 7-10), treatment field size (prostate vs. small pelvis), age (73 Gy) using Kaplan-Meier methods and compared using the Log rank test. The Cox model was used to multivariately establish independent predictors based on significant univariate factors. Median follow-up was 39 months (range: 2-84 months). Results: The 5-year actuarial rate of bNED control was 86% for the entire group of patients. The Cox Proportional Hazards model demonstrated that pretreatment PSA was an independent predictor of bNED control. Treatment field size was marginally predictive. There was no difference in bNED control when patients were stratified by the number of lobes positive for disease. Statistically different rates of bNED control were seen when the patients with nonpalpable disease were univariately compared to T2b and T2c patients. Three patients experienced Grade 3-4 genitourinary (GU) toxicity and 3 patients experienced Grade 3-4 gastrointestinal (GI) toxicity. Conclusions: Patients with nonpalpable PSA-detected prostate cancer can be effectively treated with 3DCRT with minimal morbidity and high rates of bNED control at 5 years. Pretreatment

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

    Purpose: To describe our 3-dimensional conformal planning approaches and report early toxicities with stereotactic body radiation therapy for the management of primary renal cell carcinoma. Methods and Materials: This is an analysis of a phase 1 trial of stereotactic body radiation therapy for primary inoperable renal cell carcinoma. A dose of 42 Gy/3 fractions was prescribed to targets ≥5 cm, whereas for <5 cm 26 Gy/1 fraction was used. All patients underwent a planning 4-dimensional CT to generate a planning target volume (PTV) from a 5-mm isotropic expansion of the internal target volume. Planning required a minimum of 8 fields prescribing to the minimum isodose surrounding the PTV. Intermediate dose spillage at 50% of the prescription dose (R50%) was measured to describe the dose gradient. Early toxicity (<6 months) was scored using the Common Terminology Criteria for Adverse Events (v4.0). Results: From July 2012 to August 2013 a total of 20 patients (median age, 77 years) were recruited into a prospective clinical trial. Eleven patients underwent fractionated treatment and 9 patients a single fraction. For PTV targets <100 cm3 the median number of beams used was 8 (2 noncoplanar) to achieve an average R50% of 3.7. For PTV targets >100 cm3 the median beam number used was 10 (4 noncoplanar) for an average R50% value of 4.3. The R50% was inversely proportional to decreasing PTV volume (r=−0.62, P=.003) and increasing total beams used (r=−0.51, P=.022). Twelve of 20 patients (60%) suffered grade ≤2 early toxicity, whereas 8 of 20 patients (40%) were asymptomatic. Nausea, chest wall pain, and fatigue were the most common toxicities reported. Conclusion: A 3-dimensional conformal planning technique of 8-10 beams can be used to deliver highly tolerable stereotactic ablation to primary kidney targets with minimal early toxicities. Ongoing follow-up is currently in place to assess long-term toxicities and cancer control

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

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

    2014-12-01

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

  9. Five-Year Outcomes, Cosmesis, and Toxicity With 3-Dimensional Conformal External Beam Radiation Therapy to Deliver Accelerated Partial Breast Irradiation

    Purpose: To report the interim results from a study comparing the efficacy, toxicity, and cosmesis of breast-conserving treatment with accelerated partial breast irradiation (APBI) or whole breast irradiation (WBI) using 3-dimensional conformal external beam radiation therapy (3D-CRT). Methods and Materials: 102 patients with early-stage breast cancer who underwent breast-conserving surgery were randomized to receive either WBI (n=51) or APBI (n=51). In the WBI arm, 48 Gy was delivered to the whole breast in daily fractions of 2 Gy, with or without additional 10 Gy to the tumor bed. In the APBI arm, patients received 37.5 Gy in 3.75 Gy per fraction delivered twice daily. Toxicity results were scored according to the Radiation Therapy Oncology Group Common Toxicity Criteria. Skin elasticity was measured using a dedicated device (Multi-Skin-Test-Center MC-750-B2, CKelectronic-GmbH). Cosmetic results were assessed by the physician and the patients as good/excellent, regular, or poor. Results: The median follow-up time was 5 years. No local recurrences were observed. No significant differences in survival rates were found. APBI reduced acute side effects and radiation doses to healthy tissues compared with WBI (P75% of patients in the APBI arm had excellent or good cosmesis, and these outcomes appear to be stable over time. The percentage of patients with excellent/good cosmetic results was similar in both groups. Conclusions: APBI delivered by 3D-CRT to the tumor bed for a selected group of early-stage breast cancer patients produces 5-year results similar to those achieved with conventional WBI

  10. Treatment-Related Morbidity in Prostate Cancer: A Comparison of 3-Dimensional Conformal Radiation Therapy With and Without Image Guidance Using Implanted Fiducial Markers

    Singh, Jasmeet, E-mail: drsingh.j@gmail.com [Calvary Mater Newcastle, Newcastle (Australia); Greer, Peter B. [School of Physical and Mathematical Sciences, University of Newcastle, Newcastle (Australia); White, Martin A. [School of Medicine and Public Health, University of Newcastle, Newcastle (Australia); Parker, Joel; Patterson, Jackie [Calvary Mater Newcastle, Newcastle (Australia); Tang, Colin I.; Capp, Anne; Wratten, Christopher; Denham, James W. [Calvary Mater Newcastle, Newcastle (Australia); School of Medicine and Public Health, University of Newcastle, Newcastle (Australia)

    2013-03-15

    Purpose: To estimate the prevalence of rectal and urinary dysfunctional symptoms using image guided radiation therapy (IGRT) with fiducials and magnetic resonance planning for prostate cancer. Methods and Materials: During the implementation stages of IGRT between September 2008 and March 2010, 367 consecutive patients were treated with prostatic irradiation using 3-dimensional conformal radiation therapy with and without IGRT (non-IGRT). In November 2010, these men were asked to report their bowel and bladder symptoms using a postal questionnaire. The proportions of patients with moderate to severe symptoms in these groups were compared using logistic regression models adjusted for tumor and treatment characteristic variables. Results: Of the 282 respondents, the 154 selected for IGRT had higher stage tumors, received higher prescribed doses, and had larger volumes of rectum receiving high dosage than did the 128 selected for non-IGRT. The follow-up duration was 8 to 26 months. Compared with the non-IGRT group, improvement was noted in all dysfunctional rectal symptoms using IGRT. In multivariable analyses, IGRT improved rectal pain (odds ratio [OR] 0.07 [0.009-0.7], P=.02), urgency (OR 0.27 [0.11-0.63], P=<.01), diarrhea (OR 0.009 [0.02-0.35], P<.01), and change in bowel habits (OR 0.18 [0.06-0.52], P<.010). No correlation was observed between rectal symptom levels and dose-volume histogram data. Urinary dysfunctional symptoms were similar in both treatment groups. Conclusions: In comparison with men selected for non-IGRT, a significant reduction of bowel dysfunctional symptoms was confirmed in men selected for IGRT, even though they had larger volumes of rectum treated to higher doses.

  11. Impact of Gemcitabine Chemotherapy and 3-Dimensional Conformal Radiation Therapy/5-Fluorouracil on Quality of Life of Patients Managed for Pancreatic Cancer

    Purpose: To report quality of life (QOL) results for patients receiving chemoradiation therapy for pancreatic cancer. Methods and Materials: Eligible patients (n=41 locally advanced, n=22 postsurgery) entered the B9E-AY-S168 study and received 1 cycle of induction gemcitabine (1000 mg/m2 weekly ×3 with 1-week break) followed by 3-dimensional conformal radiation therapy (RT) (54 Gy locally advanced and 45 Gy postsurgery) and concomitant continuous-infusion 5-fluorouracil (5FU) (200 mg/m2/d throughout RT). After 4 weeks, patients received an additional 3 cycles of consolidation gemcitabine chemotherapy. Patients completed the European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-PAN26 questionnaires at baseline, before RT/5FU, at end of RT/5FU, before consolidation gemcitabine, and at treatment completion. Results: The patterns of change in global QOL scores differed between groups. In the locally advanced group global QOL scores were +13, +8, +3, and +1 compared with baseline before RT/5FU (P=.008), at end of RT/5FU, before consolidation gemcitabine, and at treatment completion, respectively. In the postsurgery group, global QOL scores were −3, +4, +15, and +17 compared with baseline at the same time points, with a significant improvement in global QOL before consolidation gemcitabine (P=.03). No significant declines in global QOL were reported by either cohort. Conclusions: This study demonstrates that global QOL and associated function and symptom profiles for pancreatic chemoradiation therapy differ between locally advanced and postsurgery patients, likely owing to differences in underlying disease status. For both groups, the treatment protocol was well tolerated and did not have a negative impact on patients' global QOL.

  12. Impact of Gemcitabine Chemotherapy and 3-Dimensional Conformal Radiation Therapy/5-Fluorouracil on Quality of Life of Patients Managed for Pancreatic Cancer

    Short, Michala [Discipline of Medical Radiation Sciences, University of Sydney, Sydney, New South Wales (Australia); Western Australia Centre for Cancer and Palliative Care/Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia (Australia); Goldstein, David [Department of Medical Oncology, Prince of Wales Hospital, Sydney, New South Wales (Australia); Halkett, Georgia [Western Australia Centre for Cancer and Palliative Care/Curtin Health Innovation Research Institute, Curtin University, Perth, Western Australia (Australia); Reece, William [Covance Asia Pacific, Sydney, New South Wales (Australia); Borg, Martin [Adelaide Radiotherapy Centre, Adelaide, South Australia (Australia); Zissiadis, Yvonne [Department of Radiation Oncology, Royal Perth Hospital, Perth, Western Australia (Australia); Kneebone, Andrew [Northern Sydney Cancer Centre, Royal North Shore Hospital, Sydney, New South Wales (Australia); Spry, Nigel, E-mail: Nigel.Spry@health.wa.gov.au [Department of Radiation Oncology, Sir Charles Gairdner Hospital, Perth, Western Australia (Australia); Faculty of Medicine, University of Western Australia, Perth, Western Australia (Australia)

    2013-01-01

    Purpose: To report quality of life (QOL) results for patients receiving chemoradiation therapy for pancreatic cancer. Methods and Materials: Eligible patients (n=41 locally advanced, n=22 postsurgery) entered the B9E-AY-S168 study and received 1 cycle of induction gemcitabine (1000 mg/m{sup 2} weekly Multiplication-Sign 3 with 1-week break) followed by 3-dimensional conformal radiation therapy (RT) (54 Gy locally advanced and 45 Gy postsurgery) and concomitant continuous-infusion 5-fluorouracil (5FU) (200 mg/m{sup 2}/d throughout RT). After 4 weeks, patients received an additional 3 cycles of consolidation gemcitabine chemotherapy. Patients completed the European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-PAN26 questionnaires at baseline, before RT/5FU, at end of RT/5FU, before consolidation gemcitabine, and at treatment completion. Results: The patterns of change in global QOL scores differed between groups. In the locally advanced group global QOL scores were +13, +8, +3, and +1 compared with baseline before RT/5FU (P=.008), at end of RT/5FU, before consolidation gemcitabine, and at treatment completion, respectively. In the postsurgery group, global QOL scores were -3, +4, +15, and +17 compared with baseline at the same time points, with a significant improvement in global QOL before consolidation gemcitabine (P=.03). No significant declines in global QOL were reported by either cohort. Conclusions: This study demonstrates that global QOL and associated function and symptom profiles for pancreatic chemoradiation therapy differ between locally advanced and postsurgery patients, likely owing to differences in underlying disease status. For both groups, the treatment protocol was well tolerated and did not have a negative impact on patients' global QOL.

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

    Yartsev Slav

    2008-01-01

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

  14. Five-Year Outcomes, Cosmesis, and Toxicity With 3-Dimensional Conformal External Beam Radiation Therapy to Deliver Accelerated Partial Breast Irradiation

    Rodríguez, Núria, E-mail: nrodriguez@parcdesalutmar.cat [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain); Sanz, Xavier [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain); Dengra, Josefa [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Foro, Palmira [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain); Membrive, Ismael; Reig, Anna [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Quera, Jaume [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain); Fernández-Velilla, Enric; Pera, Óscar; Lio, Jackson; Lozano, Joan [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Algara, Manuel [Department of Radiation Oncology, Hospital de la Esperanza, Parc de Salut MAR, Barcelona (Spain); Universidad Pompeu Fabra, Barcelona (Spain)

    2013-12-01

    Purpose: To report the interim results from a study comparing the efficacy, toxicity, and cosmesis of breast-conserving treatment with accelerated partial breast irradiation (APBI) or whole breast irradiation (WBI) using 3-dimensional conformal external beam radiation therapy (3D-CRT). Methods and Materials: 102 patients with early-stage breast cancer who underwent breast-conserving surgery were randomized to receive either WBI (n=51) or APBI (n=51). In the WBI arm, 48 Gy was delivered to the whole breast in daily fractions of 2 Gy, with or without additional 10 Gy to the tumor bed. In the APBI arm, patients received 37.5 Gy in 3.75 Gy per fraction delivered twice daily. Toxicity results were scored according to the Radiation Therapy Oncology Group Common Toxicity Criteria. Skin elasticity was measured using a dedicated device (Multi-Skin-Test-Center MC-750-B2, CKelectronic-GmbH). Cosmetic results were assessed by the physician and the patients as good/excellent, regular, or poor. Results: The median follow-up time was 5 years. No local recurrences were observed. No significant differences in survival rates were found. APBI reduced acute side effects and radiation doses to healthy tissues compared with WBI (P<.01). Late skin toxicity was no worse than grade 2 in either group, without significant differences between the 2 groups. In the ipsilateral breast, the areas that received the highest doses (ie, the boost or quadrant) showed the greatest loss of elasticity. WBI resulted in a greater loss of elasticity in the high-dose area compared with APBI (P<.05). Physician assessment showed that >75% of patients in the APBI arm had excellent or good cosmesis, and these outcomes appear to be stable over time. The percentage of patients with excellent/good cosmetic results was similar in both groups. Conclusions: APBI delivered by 3D-CRT to the tumor bed for a selected group of early-stage breast cancer patients produces 5-year results similar to those achieved with

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

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

  16. Preliminary Toxicity Analysis of 3-Dimensional Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy on the High-Dose Arm of the Radiation Therapy Oncology Group 0126 Prostate Cancer Trial

    Michalski, Jeff M., E-mail: jmichalski@radonc.wustl.edu [Department of Radiation Oncology Washington University Medical Center, St. Louis, Missouri (United States); Yan, Yan [Radiation Therapy Oncology Group Statistical Center, Philadelphia, Pennsylvania (United States); Watkins-Bruner, Deborah [Emory University School of Nursing, Atlanta, Georgia (United States); Bosch, Walter R. [Department of Radiation Oncology Washington University Medical Center, St. Louis, Missouri (United States); Winter, Kathryn [Radiation Therapy Oncology Group Statistical Center, Philadelphia, Pennsylvania (United States); Galvin, James M. [Department of Radiation Oncology Thomas Jefferson University Hospital, Philadelphia, Pennsylvania (United States); Bahary, Jean-Paul [Department of Radiation Oncology Centre Hospitalier de l' Université de Montréal-Notre Dame, Montreal, QC (Canada); Morton, Gerard C. [Department of Radiation Oncology Toronto-Sunnybrook Regional Cancer Centre, Toronto, ON (Canada); Parliament, Matthew B. [Department of Oncology Cross Cancer Institute, Edmonton, AB (Canada); Sandler, Howard M. [Department of Radiation Oncology Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California (United States)

    2013-12-01

    Purpose: To give a preliminary report of clinical and treatment factors associated with toxicity in men receiving high-dose radiation therapy (RT) on a phase 3 dose-escalation trial. Methods and Materials: The trial was initiated with 3-dimensional conformal RT (3D-CRT) and amended after 1 year to allow intensity modulated RT (IMRT). Patients treated with 3D-CRT received 55.8 Gy to a planning target volume that included the prostate and seminal vesicles, then 23.4 Gy to prostate only. The IMRT patients were treated to the prostate and proximal seminal vesicles to 79.2 Gy. Common Toxicity Criteria, version 2.0, and Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer late morbidity scores were used for acute and late effects. Results: Of 763 patients randomized to the 79.2-Gy arm of Radiation Therapy Oncology Group 0126 protocol, 748 were eligible and evaluable: 491 and 257 were treated with 3D-CRT and IMRT, respectively. For both bladder and rectum, the volumes receiving 65, 70, and 75 Gy were significantly lower with IMRT (all P<.0001). For grade (G) 2+ acute gastrointestinal/genitourinary (GI/GU) toxicity, both univariate and multivariate analyses showed a statistically significant decrease in G2+ acute collective GI/GU toxicity for IMRT. There were no significant differences with 3D-CRT or IMRT for acute or late G2+ or 3+ GU toxicities. Univariate analysis showed a statistically significant decrease in late G2+ GI toxicity for IMRT (P=.039). On multivariate analysis, IMRT showed a 26% reduction in G2+ late GI toxicity (P=.099). Acute G2+ toxicity was associated with late G3+ toxicity (P=.005). With dose–volume histogram data in the multivariate analysis, RT modality was not significant, whereas white race (P=.001) and rectal V70 ≥15% were associated with G2+ rectal toxicity (P=.034). Conclusions: Intensity modulated RT is associated with a significant reduction in acute G2+ GI/GU toxicity. There is a trend for a

  17. Constituent Components of Out-of-Field Scatter Dose for 18-MV Intensity Modulated Radiation Therapy Versus 3-Dimensional Conformal Radiation Therapy: A Comparison With 6-MV and Implications for Carcinogenesis

    Purpose: To characterize and compare the components of out-of-field dose for 18-MV intensity modulated radiation therapy (IMRT) versus 3-dimensional conformal radiation therapy (3D-CRT) and their 6-MV counterparts and consider implications for second cancer induction. Methods and Materials: Comparable plans for each technique/energy were delivered to a water phantom with a sloping wall; under full scatter conditions; with field edge abutting but outside the bath to prevent internal/phantom scatter; and with shielding below the linear accelerator head to attenuate head leakage. Neutron measurements were obtained from published studies. Results: Eighteen-megavolt IMRT produces 1.7 times more out-of-field scatter than 18-MV 3D-CRT. In absolute terms, however, differences are just approximately 0.1% of central axis dose. Eighteen-megavolt IMRT reduces internal/patient scatter by 13%, but collimator scatter (C) is 2.6 times greater than 18-MV 3D-CRT. Head leakage (L) is minimal. Increased out-of-field photon scatter from 18-MV IMRT carries out-of-field second cancer risks of approximately 0.2% over and above the 0.4% from 18-MV 3D-CRT. Greater photoneutron dose from 18-MV IMRT may result in further maximal, absolute increased risk to peripheral tissue of approximately 1.2% over 18-MV 3D-CRT. Out-of-field photon scatter remains comparable for the same modality irrespective of beam energy. Machine scatter (C+L) from 18 versus 6 MV is 1.2 times higher for IMRT and 1.8 times for 3D-CRT. It is 4 times higher for 6-MV IMRT versus 3D-CRT. Reduction in internal scatter with 18 MV versus 6 MV is 27% for 3D-CRT and 29% for IMRT. Compared with 6-MV 3D-CRT, 18-MV IMRT increases out-of-field second cancer risk by 0.2% from photons and adds 0.28-2.2% from neutrons. Conclusions: Out-of-field photon dose seems to be independent of beam energy for both techniques. Eighteen-megavolt IMRT increases out-of-field scatter 1.7-fold over 3D-CRT because of greater collimator scatter despite

  18. 3-dimensional conformal radiotherapy for cervical and upper-thoracic esophageal cancer

    Objective: To evaluate the effect of 3-dimensional conformal radiotherapy (3D CRT) and prognostic factors for cervical and upper-thoracic esophageal cancer. Methods: Between July 1998 and July 2001, 33 patients with cervical and upper-thoracic esophageal cancer were treated with 3D CRT(2 Gy per day, 5 sessions a week to a total dose of 66-68 Gy over 6-7 weeks). Acute toxicities and survival rates were evaluated by Kaplan-Meier method and prognostic factors were analyzed by Cox proportional hazard model. Results: The 1-, 2-, 3-year local control rates were 87.9%, 75.8%, 45.5% respectively. The 1-, 2-, 3-year disease-free and overall survival rates were 72.7%, 60.6%, 30.3% and 78.8%, 66.8%, 44.2% respectively. GradeI- II acute esophagitis and bronchitis were the most common radiation side effects. Multivariate analysis revealed that the depth of primary tumor invasion, regional lymph node metastasis and tumor length were independent prognostic factors (P<0.05). Conclusions: 3D CRT can be considered as an effective and feasible approach to cervical and upper-thoracic esophageal cancer treatment. The depth of primary tumor invasion, regional lymph node status and tumor length are important prognostic indicators for cervical and upper-thoracic esophageal cancer. (authors)

  19. Evaluation of xerostomia following 3 dimensional conformal radiotherapy for nasopharyngeal cancer patients

    This study is to evaluate the xerostomia following 3-dimensional conformal radiation therapy (3D CRT) in nasopharynx cancer patients using the xerostomia questionnaire score (XQS). Questionnaire study was done on 51 patients with nasopharynx cancer who received 3D CRT from Dec. 2000 to Aug. 2005. 3D CRT technique is based on 'serial shrinking field' concept by 3 times of computed tomography (CT) simulation. Total target dose to the primary tumor was 72 Gy with 1.8 Gy daily fractions. Xerostomia was assessed with 4-questions XQS, and the associations between XQS and time elapsed after RT, age, sex, stage, concurrent chemotherapy, an parotid dose were analyzed. Concurrent chemotherapy was given to 40 patients and RT alone was given to 11 patients. The median time elapsed after 3D CRT was 20 (1 ∼ 58) months and the mean XQS of all 51 patients was 8.4 ± 1.9 (6 ∼ 14). XQS continuously and significantly decreased over time after 3D CRT (χ 2 -0.484, ρ < 0.05). There was no significant difference in XQS according to sex, age, and stag. However, XQS of concurrent chemotherapy patients was significantly higher than RT alone patients (ρ = 0.001). XQS of patients receiving total mean parotid dose ≥ 35 Gy was significantly higher than < 35 Gy (ρ = 0.05). Decreasing tendency of XQS over time after 3D CRT was observed. Concurrent chemotherapy and total mean parotid dose ≥ 35 Gy were suggested to adversely affect radiation-induced xerostomia

  20. Late Toxicity and Patient Self-Assessment of Breast Appearance/Satisfaction on RTOG 0319: A Phase 2 Trial of 3-Dimensional Conformal Radiation Therapy-Accelerated Partial Breast Irradiation Following Lumpectomy for Stages I and II Breast Cancer

    Purpose: Late toxicities and cosmetic analyses of patients treated with accelerated partial breast irradiation (APBI) on RTOG 0319 are presented. Methods and Materials: Patients with stages I to II breast cancer ≤3 cm, negative margins, and ≤3 positive nodes were eligible. Patients received three-dimensional conformal external beam radiation therapy (3D-CRT; 38.5 Gy in 10 fractions twice daily over 5 days). Toxicity and cosmesis were assessed by the patient (P), the radiation oncologist (RO), and the surgical oncologist (SO) at 3, 6, and 12 months from the completion of treatment and then annually. National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0, was used to grade toxicity. Results: Fifty-two patients were evaluable. Median follow-up was 5.3 years (range, 1.7-6.4 years). Eighty-two percent of patients rated their cosmesis as good/excellent at 1 year, with rates of 64% at 3 years. At 3 years, 31 patients were satisfied with the treatment, 5 were not satisfied but would choose 3D-CRT again, and none would choose standard radiation therapy. The worst adverse event (AE) per patient reported as definitely, probably, or possibly related to radiation therapy was 36.5% grade 1, 50% grade 2, and 5.8% grade 3 events. Grade 3 AEs were all skin or musculoskeletal-related. Treatment-related factors were evaluated to potentially establish an association with observed toxicity. Surgical bed volume, target volume, the number of beams used, and the use of bolus were not associated with late cosmesis. Conclusions: Most patients enrolled in RTOG 0319 were satisfied with their treatment, and all would choose to have the 3D-CRT APBI again

  1. Late Toxicity and Patient Self-Assessment of Breast Appearance/Satisfaction on RTOG 0319: A Phase 2 Trial of 3-Dimensional Conformal Radiation Therapy-Accelerated Partial Breast Irradiation Following Lumpectomy for Stages I and II Breast Cancer

    Chafe, Susan, E-mail: susan.chafe@albertahealthservices.ca [Department of Radiation Oncology, Cross Cancer Institute-University of Alberta, Edmonton, Alberta (Canada); Moughan, Jennifer [Department of Radiation Oncology, RTOG Statistical Center, Philadelphia, Pennsylvania (United States); McCormick, Beryl [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Wong, John [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland (United States); Pass, Helen [Womens' Breast Center, Stamford Hospital, Stamford, Connecticut (United States); Rabinovitch, Rachel [Department of Radiation Oncology, University of Colorado Denver, Aurora, Colorado (United States); Arthur, Douglas W. [Department of Radiation Oncology, Virginia Commonwealth University, Richmond, Virginia (United States); Petersen, Ivy [Department of Radiation Oncology, Mayo Clinic, Rochester, Minnesota (United States); White, Julia [Department of Radiation Oncology, Ohio State University, Columbus, Ohio (United States); Vicini, Frank A. [Michigan Healthcare Professionals/21st Century Oncology, Farmington Hills, Michigan (United States)

    2013-08-01

    Purpose: Late toxicities and cosmetic analyses of patients treated with accelerated partial breast irradiation (APBI) on RTOG 0319 are presented. Methods and Materials: Patients with stages I to II breast cancer ≤3 cm, negative margins, and ≤3 positive nodes were eligible. Patients received three-dimensional conformal external beam radiation therapy (3D-CRT; 38.5 Gy in 10 fractions twice daily over 5 days). Toxicity and cosmesis were assessed by the patient (P), the radiation oncologist (RO), and the surgical oncologist (SO) at 3, 6, and 12 months from the completion of treatment and then annually. National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0, was used to grade toxicity. Results: Fifty-two patients were evaluable. Median follow-up was 5.3 years (range, 1.7-6.4 years). Eighty-two percent of patients rated their cosmesis as good/excellent at 1 year, with rates of 64% at 3 years. At 3 years, 31 patients were satisfied with the treatment, 5 were not satisfied but would choose 3D-CRT again, and none would choose standard radiation therapy. The worst adverse event (AE) per patient reported as definitely, probably, or possibly related to radiation therapy was 36.5% grade 1, 50% grade 2, and 5.8% grade 3 events. Grade 3 AEs were all skin or musculoskeletal-related. Treatment-related factors were evaluated to potentially establish an association with observed toxicity. Surgical bed volume, target volume, the number of beams used, and the use of bolus were not associated with late cosmesis. Conclusions: Most patients enrolled in RTOG 0319 were satisfied with their treatment, and all would choose to have the 3D-CRT APBI again.

  2. Estimating the costs of intensity-modulated and 3-dimensional conformal radiotherapy in Ontario

    Yong, J.H.E.; McGowan, T.; Redmond-Misner, R.; Beca, J.; Warde, P.; Gutierrez, E.; Hoch, J.S.

    2016-01-01

    Background Radiotherapy is a common treatment for many cancers, but up-to-date estimates of the costs of radiotherapy are lacking. In the present study, we estimated the unit costs of intensity-modulated radiotherapy (imrt) and 3-dimensional conformal radiotherapy (3D-crt) in Ontario. Methods An activity-based costing model was developed to estimate the costs of imrt and 3D-crt in prostate cancer. It included the costs of equipment, staff, and supporting infrastructure. The framework was subsequently adapted to estimate the costs of radiotherapy in breast cancer and head-and-neck cancer. We also tested various scenarios by varying the program maturity and the use of volumetric modulated arc therapy (vmat) alongside imrt. Results From the perspective of the health care system, treating prostate cancer with imrt and 3D-crt respectively cost $12,834 and $12,453 per patient. The cost of radiotherapy ranged from $5,270 to $14,155 and was sensitive to analytic perspective, radiation technique, and disease site. Cases of head-and-neck cancer were the most costly, being driven by treatment complexity and fractions per treatment. Although imrt was more costly than 3D-crt, its cost will likely decline over time as programs mature and vmat is incorporated. Conclusions Our costing model can be modified to estimate the costs of 3D-crt and imrt for various disease sites and settings. The results demonstrate the important role of capital costs in studies of radiotherapy cost from a health system perspective, which our model can accommodate. In addition, our study established the need for future analyses of imrt cost to consider how vmat affects time consumption.

  3. 儿童髓母细胞瘤34例三维适形放射治疗的疗效分析%The follow-up of 34 children with medulloblastoma who received 3-dimensional conformal radiation therapy

    Dongfeng He; Siheng Ha; Changsheng Wang

    2009-01-01

    Objective: In our investigation, we studied the patients with medulloblastoma who received 3-dimensional con- formal radiation therapy (3DCRT) and recorded their effects, side effects and failure reasons. Methods: From August 2001 to August 2007, 34 children with medulloblastoma were treated in our hospital. The age at diagnosis was 3-16 years old, and the mean age at diagnosis was 9.5 years old. Among all the patients, 16 cases were included in the high risk group and 18cases were included in the low risk group. All the patients were performed total resection or subtotal resection and no patientsreceived radiotherapy or chemotherapy before operation. All patients received 3DCRT within 3 weeks after resection. The dose of 30 Gy were given to the whole brain and whole spine, followed by 20-25 Gy boosted to the posterior brain fossa. The median fraction dose was 180 cGy. Every patient received the chemotherapy scheme of the Lomustine, Cisplatinum and Vincristine. Nobody received intrathecal chemotherapy. The tests of the complete blood count, blood biochemistry, hepatic and renal functions were required before every cycle of chemotherapy. Results: 5-year overall survival (OS) and 5-year disease free survival (DFS) were 71% and 62% respectively. The median follow-up time was 36.5 months. The 5-year OS of the high risk group was 71% compared to 62% of the low risk group. There were significant difference between the two groups (P = 0.01). There were 13 failure cases in all the patients. Of these 13 patients, 10 were dead and the other 3 were alive with tumor. The complete remission (CR) rate was 70.5% and the partial remission (PR) rate was 14%. Among the failure patients, there were 3 patients (8.8%) with the recurrences located in the brain of cribriform region. The 5-year OS of the patients with preoperative metastases was 12.5% (1/8), and which of the patients with residual tumor volume > 1.5 cm3 was 0% (0/5). Through the statistic analysis, it was found that both

  4. A critical evaluation of secondary cancer risk models applied to Monte Carlo dose distributions of 2-dimensional, 3-dimensional conformal and hybrid intensity-modulated radiation therapy for breast cancer

    Joosten, A.; Bochud, F.; Moeckli, R.

    2014-08-01

    The comparison of radiotherapy techniques regarding secondary cancer risk has yielded contradictory results possibly stemming from the many different approaches used to estimate risk. The purpose of this study was to make a comprehensive evaluation of different available risk models applied to detailed whole-body dose distributions computed by Monte Carlo for various breast radiotherapy techniques including conventional open tangents, 3D conformal wedged tangents and hybrid intensity modulated radiation therapy (IMRT). First, organ-specific linear risk models developed by the International Commission on Radiological Protection (ICRP) and the Biological Effects of Ionizing Radiation (BEIR) VII committee were applied to mean doses for remote organs only and all solid organs. Then, different general non-linear risk models were applied to the whole body dose distribution. Finally, organ-specific non-linear risk models for the lung and breast were used to assess the secondary cancer risk for these two specific organs. A total of 32 different calculated absolute risks resulted in a broad range of values (between 0.1% and 48.5%) underlying the large uncertainties in absolute risk calculation. The ratio of risk between two techniques has often been proposed as a more robust assessment of risk than the absolute risk. We found that the ratio of risk between two techniques could also vary substantially considering the different approaches to risk estimation. Sometimes the ratio of risk between two techniques would range between values smaller and larger than one, which then translates into inconsistent results on the potential higher risk of one technique compared to another. We found however that the hybrid IMRT technique resulted in a systematic reduction of risk compared to the other techniques investigated even though the magnitude of this reduction varied substantially with the different approaches investigated. Based on the epidemiological data available, a reasonable

  5. Meta-analysis of incidence of early lung toxicity in 3-dimensional conformal irradiation of breast carcinomas

    This meta-analysis aims to ascertain the significance of early lung toxicity with 3-Dimensional (3D) conformal irradiation for breast carcinomas and identify the sub-groups of patients with increased risk. Electronic databases, reference sections of major oncological textbooks and identified studies were searched for synonyms of breast radiotherapy and radiation pneumonitis (RP). Major studies in thoracic irradiation were reviewed to identify factors frequently associated with RP. Meta-analysis for RP incidence estimation and odds ratio calculation were carried out. The overall incidence of Clinical and Radiological RP is 14% and 42% respectively. Ten studies were identified. Dose-volume Histogram (DVH) related dosimetric factors (Volume of lung receiving certain dose, Vdose and Mean lung Dose, MLD), supraclavicular fossa (SCF) irradiation and age are significantly associated with RP, but not sequential chemotherapy and concomitant use of Tamoxifen. A poorly powered study in IMN group contributed to the negative finding. Smoking has a trend towards protective effect against RP. Use of other modalities may be considered when Ipsilateral lung V20Gy > 30% or MLD > 15 Gy. Extra caution is needed in SCF and IMN irradiation as they are likely to influence these dosimetric parameters

  6. Preliminary results of 3-dimensional conformal radiotherapy for primary unresectable hepatocellular carcinoma

    Keum, Ki Chang; Park, Hee Chul; Seong, Jin Sil; Chang, Sei Kyoung; Han, Kwang Hyub; Chon, Chae Yoon; Moon, Young Myoung; Kim, Gwi Eon; Suh, Chang Ok [Hallym University College of Medicine, Seoul (Korea, Republic of)

    2002-06-15

    The purpose of this study was to determine the potential role of three-dimensional conformal radiotherapy (3D-CRT) in the treatment of primary unresectable hepatocellular carcinoma. The preliminary results on the efficacy and the toxicity of 3D-CRT are reported. Seventeen patients were enrolled in this study, which was conducted prospectively from January 1995 to June 1997. The exclusion criteria included the presence of extrahepatic metastasis, liver cirrhosis of Child-Pugh classification C, tumors occupying more than two thirds of the entire liver, and a performance status of more than 3 on the ECOG scale. Two patients were treated with radiotherapy only while the remaining 15 were treated with combined transcatheter arterial chemoembolization. Radiotherapy was given to the field including the tumor plus a 1.5 cm margin using a 3D-CRT technique. The radiation dose ranged from 36 {approx} 60 Gy (median: 59.4 Gy). Tumor response was based on a radiological examination such as the CT scan, MR imaging, and hepatic artery angiography at 4 {approx} 8 weeks following the completion of treatment. The acute and subacute toxicities were monitored. An objective response was observed in 11 out of 17 patients, giving a response rate of 64.7%. The actuarial survival rate at 2 years was 21.2% from the start of radiotherapy (median survival; 19 months). Six patients developed a distant metastasis consisting of a lung metastasis in 5 patients and bone metastasis in one. The complications related to 3D-CRT were gastro-duodenitis ({>=} grade 2) in 2 patients. There were no treatment related deaths and radiation induced hepatitis. The preliminary results show that 3D-CRT is a reliable and effective treatment modality for primary unresectable hepatocellular carcinoma compared to other conventional modalities. Further studies to evaluate the definitive role of the 3D-CRT technique in the treatment of primary unresectable hepatocellular carcinoma are needed.

  7. Preliminary results of 3-dimensional conformal radiotherapy for primary unresectable hepatocellular carcinoma

    The purpose of this study was to determine the potential role of three-dimensional conformal radiotherapy (3D-CRT) in the treatment of primary unresectable hepatocellular carcinoma. The preliminary results on the efficacy and the toxicity of 3D-CRT are reported. Seventeen patients were enrolled in this study, which was conducted prospectively from January 1995 to June 1997. The exclusion criteria included the presence of extrahepatic metastasis, liver cirrhosis of Child-Pugh classification C, tumors occupying more than two thirds of the entire liver, and a performance status of more than 3 on the ECOG scale. Two patients were treated with radiotherapy only while the remaining 15 were treated with combined transcatheter arterial chemoembolization. Radiotherapy was given to the field including the tumor plus a 1.5 cm margin using a 3D-CRT technique. The radiation dose ranged from 36 ∼ 60 Gy (median: 59.4 Gy). Tumor response was based on a radiological examination such as the CT scan, MR imaging, and hepatic artery angiography at 4 ∼ 8 weeks following the completion of treatment. The acute and subacute toxicities were monitored. An objective response was observed in 11 out of 17 patients, giving a response rate of 64.7%. The actuarial survival rate at 2 years was 21.2% from the start of radiotherapy (median survival; 19 months). Six patients developed a distant metastasis consisting of a lung metastasis in 5 patients and bone metastasis in one. The complications related to 3D-CRT were gastro-duodenitis (≥ grade 2) in 2 patients. There were no treatment related deaths and radiation induced hepatitis. The preliminary results show that 3D-CRT is a reliable and effective treatment modality for primary unresectable hepatocellular carcinoma compared to other conventional modalities. Further studies to evaluate the definitive role of the 3D-CRT technique in the treatment of primary unresectable hepatocellular carcinoma are needed

  8. Conformal pure radiation with parallel rays

    Leistner, Thomas

    2011-01-01

    We define pure radiation metrics with parallel rays to be n-dimensional pseudo-Riemannian metrics that admit a parallel null line bundle K and whose Ricci tensor vanishes on vectors that are orthogonal to K. We give necessary conditions in terms of the Weyl, Cotton and Bach tensors for a pseudo-Riemannian metric to be conformal to a pure radiation metric with parallel rays. Then we derive conditions in terms of tractor calculus that are equivalent to the existence of a pure radiation metric with parallel rays in a conformal class. We also give an analogous result for n-dimensional pseudo-Riemannian pp-waves.

  9. Conformal pure radiation with parallel rays

    Leistner, Thomas; Nurowski, Paweł

    2012-03-01

    We define pure radiation metrics with parallel rays to be n-dimensional pseudo-Riemannian metrics that admit a parallel null line bundle K and whose Ricci tensor vanishes on vectors that are orthogonal to K. We give necessary conditions in terms of the Weyl, Cotton and Bach tensors for a pseudo-Riemannian metric to be conformal to a pure radiation metric with parallel rays. Then, we derive conditions in terms of the tractor calculus that are equivalent to the existence of a pure radiation metric with parallel rays in a conformal class. We also give analogous results for n-dimensional pseudo-Riemannian pp-waves.

  10. Absence of toxicity with hypofractionated 3-dimensional radiation therapy for inoperable, early stage non-small cell lung cancer

    Hypofractionated radiotherapy may overcome repopulation in rapidly proliferating tumors such as lung cancer. It is more convenient for the patients and reduces health care costs. This study reports our results on patients with medically inoperable, early stage, non-small cell lung cancer (NSCLC) treated with hypofractionation. Stage T1-2N0 NSCLC patients were treated with hypofractionation alone, 52.5 Gy/15 fractions, in 3 weeks, with 3-dimensional conformal planning. T1-2N1 patients with the hilar lymphnode close to the primary tumor were also eligible for this treatment. We did not use any approach to reduce respiratory motion, but it was monitored in all patients. Elective nodal radiotherapy was not performed. Routine follow up included assessment for acute and late toxicity and radiological tumor response. Median follow up time was 29 months for the surviving patients. Thirty-two patients with a median age of 76 years, T1 = 15 and T2 = 17, were treated. Median planning target volume (PTV) volume was 150cc and median V16 of both lungs was 13%. The most important finding of this study is that toxicity was minimal. Two patients had grade ≤ 2 acute pneumonitis and 3 had mild (grade 1) acute esophagitis. There was no late toxicity. Actuarial 1 and 2-year overall survival rates are 78% and 56%, cancer specific survival rates (CSS) are 90% and 74%, and local relapse free survival rates are 93% and 76% respectively. 3-D planning, involved field hypofractionation at a dose of 52.5 Gy in 15 daily fractions is safe, well tolerated and easy radiation treatment for medically inoperable lung cancer patients. It shortens by half the traditional treatment. Results compare favorably with previously published studies. Further studies are needed to compare similar technique with other treatments such as surgery and stereotactic radiotherapy

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

    Leonard, Kara Lynne, E-mail: karalynne.kerr@gmail.com [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Hepel, Jaroslaw T. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States); Hiatt, Jessica R. [Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States); Dipetrillo, Thomas A. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States); Price, Lori Lyn [Department of Biostatistics Research Center, Institute of Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, Massachusetts (United States); Wazer, David E. [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts (United States); Department of Radiation Oncology, Rhode Island Hospital, Warren Alpert School of Medicine of Brown University, Providence, Rhode Island (United States)

    2013-03-01

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

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

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

  13. Long-term Cosmetic Outcomes and Toxicities of Proton Beam Therapy Compared With Photon-Based 3-Dimensional Conformal Accelerated Partial-Breast Irradiation: A Phase 1 Trial

    Galland-Girodet, Sigolène; Pashtan, Itai; MacDonald, Shannon M.; Ancukiewicz, Marek [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Hirsch, Ariel E.; Kachnic, Lisa A. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Department of Radiation Oncology, Boston Medical Center, Boston University School of Medicine, Boston, Massachusetts (United States); Specht, Michelle; Gadd, Michele; Smith, Barbara L. [Department of Surgical Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Powell, Simon N. [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Recht, Abram [Department of Radiation Oncology, Beth Israel Deaconess Medical Center, Boston, Massachusetts (United States); Taghian, Alphonse G., E-mail: ataghian@partners.org [Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2014-11-01

    Purpose: To present long-term outcomes of a prospective feasibility trial using either protons or 3-dimensional conformal photon-based (accelerated partial-breast irradiation [APBI]) techniques. Methods and Materials: From October 2003 to April 2006, 98 evaluable patients with stage I breast cancer were treated with APBI (32 Gy in 8 fractions given twice daily) on a prospective clinical trial: 19 with proton beam therapy (PBT) and 79 with photons or mixed photons/electrons. Median follow-up was 82.5 months (range, 2-104 months). Toxicity and patient satisfaction evaluations were performed at each visit. Results: At 7 years, the physician rating of overall cosmesis was good or excellent for 62% of PBT patients, compared with 94% for photon patients (P=.03). Skin toxicities were more common for the PBT group: telangiectasia, 69% and 16% (P=.0013); pigmentation changes, 54% and 22% (P=.02); and other late skin toxicities, 62% and 18% (P=.029) for PBT and photons, respectively. There were no significant differences between the groups in the incidences of breast pain, edema, fibrosis, fat necrosis, skin desquamation, and rib pain or fracture. Patient-reported cosmetic outcomes at 7 years were good or excellent for 92% and 96% of PBT and photon patients, respectively (P=.95). Overall patient satisfaction was 93% for the entire cohort. The 7-year local failure rate for all patients was 6%, with 3 local recurrences in the PBT group (7-year rate, 11%) and 2 in photon-treated patients (4%) (P=.22). Conclusions: Local failure rates of 3-dimensional APBI and PBT were similar in this study. However, PBT, as delivered in this study, led to higher rates of long-term telangiectasia, skin color changes, and skin toxicities. We recommend the use of multiple fields and treatment of all fields per treatment session or the use of scanning techniques to minimize skin toxicity.

  14. Long-term Cosmetic Outcomes and Toxicities of Proton Beam Therapy Compared With Photon-Based 3-Dimensional Conformal Accelerated Partial-Breast Irradiation: A Phase 1 Trial

    Purpose: To present long-term outcomes of a prospective feasibility trial using either protons or 3-dimensional conformal photon-based (accelerated partial-breast irradiation [APBI]) techniques. Methods and Materials: From October 2003 to April 2006, 98 evaluable patients with stage I breast cancer were treated with APBI (32 Gy in 8 fractions given twice daily) on a prospective clinical trial: 19 with proton beam therapy (PBT) and 79 with photons or mixed photons/electrons. Median follow-up was 82.5 months (range, 2-104 months). Toxicity and patient satisfaction evaluations were performed at each visit. Results: At 7 years, the physician rating of overall cosmesis was good or excellent for 62% of PBT patients, compared with 94% for photon patients (P=.03). Skin toxicities were more common for the PBT group: telangiectasia, 69% and 16% (P=.0013); pigmentation changes, 54% and 22% (P=.02); and other late skin toxicities, 62% and 18% (P=.029) for PBT and photons, respectively. There were no significant differences between the groups in the incidences of breast pain, edema, fibrosis, fat necrosis, skin desquamation, and rib pain or fracture. Patient-reported cosmetic outcomes at 7 years were good or excellent for 92% and 96% of PBT and photon patients, respectively (P=.95). Overall patient satisfaction was 93% for the entire cohort. The 7-year local failure rate for all patients was 6%, with 3 local recurrences in the PBT group (7-year rate, 11%) and 2 in photon-treated patients (4%) (P=.22). Conclusions: Local failure rates of 3-dimensional APBI and PBT were similar in this study. However, PBT, as delivered in this study, led to higher rates of long-term telangiectasia, skin color changes, and skin toxicities. We recommend the use of multiple fields and treatment of all fields per treatment session or the use of scanning techniques to minimize skin toxicity

  15. Delineation of lymphnodal levels on CT: standardization of portals and 3-dimensional conformal radiotherapy (3DCRT) of the neck

    Purpose/Objective: To establish the exact position - and a reproducible protocol for the delineation - of the lymphnodal levels in the neck on CT-slices, in order to standardize neck portals and, to study the merits of 3DCRT for sparing of critical tissues in (elective) neck irradiation. Materials and Methods: Firstly, in a nation wide inventory the variation in applied portals for elective neck irradiation (ENI) was investigated. In this study, 16 experienced radiation-oncologists (ROs) from 11 major H and N co-operative groups, were asked to delineate on (copies of) simulation films of a single patient routine portals for elective neck irradiation (ENI), in case of a T2 mobile tongue cancer and a T3 tumor of the supraglottic larynx. The portals and the Beams Eye View-outlines of the major salivary glands (delineated on a CT scan of the same patient in treatment position), were digitized. Secondly, to establish a reproducible protocol for the delineation of lymphnodal levels on CT-slices, two human frozen specimen were sectioned into 5 mm thick slices. The photographed and digitized slices were matched with transversal CT images from the same specimen. Then, anatomical landmarks of the well defined and established lymphnodal levels customarily used in surgery of the neck, were identified on the photographs of the human specimen slices, and subsequently transcribed onto the corresponding CT images. This way the surgical levels I-VI could be translated into CT based regions (1-6), with the latter being defined by landmarks visible on CT-slices. A first assessment of the adequacy and reproducibility of the developed protocol for the delineation of the lymphnodal regions on CT was made by four independent ROs using the CT data of five patients. Thirdly, the consequences of the observed variation in delineated portals of the nation wide inventory, both for the critical normal tissues (major salivary glands) as well as with regard to the (CT-defined) lymphnodal regions

  16. Effects of radiational damping in 3-dimensional soil-structure interaction system with basemat uplift

    The purpose of this paper is to evaluate the change in structural responses due to the radiational damping which varies with the extent of basemat uplift. The necessity of using nonlinear variation of radiational damping in relation to the extent of uplift is studied. The importance of considering nonlinear variation of damping during uplift for different base-soil conditions is also discussed. (J.P.N.)

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

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

    1995-12-01

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

  18. Comparison of 1-, 2-, and 3-dimensional modeling of the TFTR for nuclear radiation transport analysis

    The computational models of the TFTR constructed for the radiation transport analysis for the Q approx. 1 demonstration are summarized and reviewed. These models can be characterized by the dimensionality required to describe the geometry, and by the numerical methods of solving the transport equation. Results obtained with these models in the test cell are compared and discussed

  19. Volumetric-modulated arc radiotherapy for pancreatic malignancies: Dosimetric comparison with sliding-window intensity-modulated radiotherapy and 3-dimensional conformal radiotherapy

    Nabavizadeh, Nima, E-mail: nabaviza@ohsu.edu; Simeonova, Anna O.; Waller, Joseph G.; Romer, Jeanna L.; Monaco, Debra L.; Elliott, David A.; Tanyi, James A.; Fuss, Martin; Thomas, Charles R.; Holland, John M.

    2014-10-01

    Volumetric-modulated arc radiotherapy (VMAT) is an iteration of intensity-modulated radiotherapy (IMRT), both of which deliver highly conformal dose distributions. Studies have shown the superiority of VMAT and IMRT in comparison with 3-dimensional conformal radiotherapy (3D-CRT) in planning target volume (PTV) coverage and organs-at-risk (OARs) sparing. This is the first study examining the benefits of VMAT in pancreatic cancer for doses more than 55.8 Gy. A planning study comparing 3D-CRT, IMRT, and VMAT was performed in 20 patients with pancreatic cancer. Treatments were planned for a 25-fraction delivery of 45 Gy to a large field followed by a reduced-volume 8-fraction external beam boost to 59.4 Gy in total. OARs and PTV doses, conformality index (CI) deviations from 1.0, monitor units (MUs) delivered, and isodose volumes were compared. IMRT and VMAT CI deviations from 1.0 for the large-field and the boost plans were equivalent (large field: 0.032 and 0.046, respectively; boost: 0.042 and 0.037, respectively; p > 0.05 for all comparisons). Both IMRT and VMAT CI deviations from 1.0 were statistically superior to 3D-CRT (large field: 0.217, boost: 0.177; p < 0.05 for all comparisons). VMAT showed reduction of the mean dose to the boost PTV (VMAT: 61.4 Gy, IMRT: 62.4 Gy, and 3D-CRT: 62.3 Gy; p < 0.05). The mean number of MUs per fraction was significantly lower for VMAT for both the large-field and the boost plans. VMAT delivery time was less than 3 minutes compared with 8 minutes for IMRT. Although no statistically significant dose reduction to the OARs was identified when comparing VMAT with IMRT, VMAT showed a reduction in the volumes of the 100% isodose line for the large-field plans. Dose escalation to 59.4 Gy in pancreatic cancer is dosimetrically feasible with shorter treatment times, fewer MUs delivered, and comparable CIs for VMAT when compared with IMRT.

  20. Accuracy Evaluation of a 3-Dimensional Surface Imaging System for Guidance in Deep-Inspiration Breath-Hold Radiation Therapy

    Purpose: To investigate the applicability of 3-dimensional (3D) surface imaging for image guidance in deep-inspiration breath-hold radiation therapy (DIBH-RT) for patients with left-sided breast cancer. For this purpose, setup data based on captured 3D surfaces was compared with setup data based on cone beam computed tomography (CBCT). Methods and Materials: Twenty patients treated with DIBH-RT after breast-conserving surgery (BCS) were included. Before the start of treatment, each patient underwent a breath-hold CT scan for planning purposes. During treatment, dose delivery was preceded by setup verification using CBCT of the left breast. 3D surfaces were captured by a surface imaging system concurrently with the CBCT scan. Retrospectively, surface registrations were performed for CBCT to CT and for a captured 3D surface to CT. The resulting setup errors were compared with linear regression analysis. For the differences between setup errors, group mean, systematic error, random error, and 95% limits of agreement were calculated. Furthermore, receiver operating characteristic (ROC) analysis was performed. Results: Good correlation between setup errors was found: R2=0.70, 0.90, 0.82 in left-right, craniocaudal, and anterior-posterior directions, respectively. Systematic errors were ≤0.17 cm in all directions. Random errors were ≤0.15 cm. The limits of agreement were −0.34-0.48, −0.42-0.39, and −0.52-0.23 cm in left-right, craniocaudal, and anterior-posterior directions, respectively. ROC analysis showed that a threshold between 0.4 and 0.8 cm corresponds to promising true positive rates (0.78-0.95) and false positive rates (0.12-0.28). Conclusions: The results support the application of 3D surface imaging for image guidance in DIBH-RT after BCS.

  1. Implementation of Remote 3-Dimensional Image Guided Radiation Therapy Quality Assurance for Radiation Therapy Oncology Group Clinical Trials

    Purpose: To report the process and initial experience of remote credentialing of three-dimensional (3D) image guided radiation therapy (IGRT) as part of the quality assurance (QA) of submitted data for Radiation Therapy Oncology Group (RTOG) clinical trials; and to identify major issues resulting from this process and analyze the review results on patient positioning shifts. Methods and Materials: Image guided radiation therapy datasets including in-room positioning CT scans and daily shifts applied were submitted through the Image Guided Therapy QA Center from institutions for the IGRT credentialing process, as required by various RTOG trials. A centralized virtual environment is established at the RTOG Core Laboratory, containing analysis tools and database infrastructure for remote review by the Physics Principal Investigators of each protocol. The appropriateness of IGRT technique and volumetric image registration accuracy were evaluated. Registration accuracy was verified by repeat registration with a third-party registration software system. With the accumulated review results, registration differences between those obtained by the Physics Principal Investigators and from the institutions were analyzed for different imaging sites, shift directions, and imaging modalities. Results: The remote review process was successfully carried out for 87 3D cases (out of 137 total cases, including 2-dimensional and 3D) during 2010. Frequent errors in submitted IGRT data and challenges in the review of image registration for some special cases were identified. Workarounds for these issues were developed. The average differences of registration results between reviewers and institutions ranged between 2 mm and 3 mm. Large discrepancies in the superior-inferior direction were found for megavoltage CT cases, owing to low spatial resolution in this direction for most megavoltage CT cases. Conclusion: This first experience indicated that remote review for 3D IGRT as part of QA

  2. Volumetric intensity-modulated arc therapy vs. 3-dimensional conformal radiotherapy for primary chemoradiotherapy of anal carcinoma. Effects on treatment-related side effects and survival

    Weber, Hanne Elisabeth; Droege, Leif Hendrik; Hennies, Steffen; Herrmann, Markus Karl; Wolff, Hendrik Andreas [University Medical Center Goettingen, Dept. of Radiotherapy and Radiooncology, Goettingen (Germany); Gaedcke, Jochen [University Medical Center Goettingen, Dept. of General Surgery, Goettingen (Germany)

    2015-11-15

    Primary chemoradiotherapy (CRT) is the standard treatment for locally advanced anal carcinoma. This study compared volumetric intensity-modulated arc therapy (VMAT) to 3-dimensional conformal radiotherapy (3DCRT) in terms of treatment-related side effects and survival. From 1992-2014, 103 consecutive patients with anal carcinoma UICC stage I-III were treated. Concomitant CRT consisted of whole pelvic irradiation, including the iliac and inguinal lymph nodes, with 50.4 Gy (1.8 Gy per fractions) by VMAT (n = 17) or 3DCRT (n = 86) as well as two cycles of 5-fluorouracil and mitomycin C. Acute organ and hematological toxicity were assessed according to the Common Terminology Criteria (CTC) for Adverse Events version 3.0. Side effects ≥ grade 3 were scored as high-grade toxicity. High-grade acute organ toxicity CTC ≥ 3 (P < 0.05), especially proctitis (P = 0.03), was significantly reduced in VMAT patients. The 2-year locoregional control (LRC) and disease-free survival (DFS) were both 100 % for VMAT patients compared with 80 and 73 % for 3DCRT patients. VMAT was shown to be a feasible technique, achieving significantly lower rates of acute organ toxicity and promising results for LRC and DFS. Future investigations will aim at assessing the advantages of VMAT with respect to late toxicity and survival after a prolonged follow-up time. (orig.) [German] Die primaere Radiochemotherapie (RCT) gilt als Standardtherapie fuer lokal fortgeschrittene Analkarzinome. In dieser Studie wurde die volumetrisch modulierte Rotationstherapie (''volumetric intensity-modulated arc therapy'', VMAT) mit der klassischen dreidimensionalen konformalen Radiotherapie (3DCRT) hinsichtlich therapieassoziierter Nebenwirkungen und Ueberleben verglichen. Von 1992-2014 wurden 103 aufeinanderfolgende Patienten mit einem Analkarzinom im UICC-Stadium I-III behandelt. Die kombinierte RCT bestand aus der Bestrahlung des gesamten Beckens inklusive der iliakalen und der inguinalen

  3. Transcriptional profiling of radiation damage and preventive treatments in a 3-dimensional (3D) human cell culture model of oral mucositis

    Lambros, Maria P.; DeSalvo, Michael K.; Jonathan Moreno; Hari Chandana Mulamalla; Lavanya Kondapalli

    2015-01-01

    Cancer patients who receive radiation are often afflicted by oral mucositis, a debilitating disease, characterized by mouth sores and difficulty in swallowing. Oftentimes, cancer patients afflicted with mucositis must stop life-saving therapies. Thus it is very important to prevent mucositis before it develops. Using a validated organotypic model of human oral mucosa, a 3-dimensional cell culture model of human oral keratinocytes, it has been shown that a mixture (NAC–QYD) of N-acetyl cystein...

  4. The analysis of prognostic factors affecting post-radiation acute reaction after conformal radiotherapy for non-small cell lung cancer

    Spych, Michał; Gottwald, Leszek; Klonowicz, Małgorzata; Biegała, Michał; Bibik, Robert; Fijuth, Jacek

    2010-01-01

    Introduction The aim was to evaluate the risk of acute side effects in the lung after 3-dimensional conformal radiotherapy (3D-CRT) in patients treated for non-small cell lung cancer (NSCLC). An attempt was made to single out clinical factors and factors related to treatment technique which may induce acute post-radiation pneumonitis. Material and methods The analysis concerned 34 consecutive patients who underwent radical radiation therapy for NSCLC. Intensity of early toxicity was evaluated...

  5. Conformal nature of the Hawking radiation

    String theory usually represents quantum black holes as systems whose statistical mechanics reproduces Hawking's thermodynamics in a very satisfactory way. Complicated brane theoretical models are worked out, as quantum versions of Supergravity solutions. These models are then assumed to be in thermal equilibrium: this is a little cheating, because one is looking for an explanation of the seeming thermodynamical nature of black holes, so they cannot be assumed to be finite temperature systems! In the model presented here, the black body spectrum arises with no statistical hypothesis as an approximation of the unitary evolution of microscopic black holes, which are always described by a 1+1 conformal field theory, characterized by some Virasoro algebra. At the end, one can state that the Hawking-thermodynamics of the system is a by-product of the algebraic Virasoro-symmetric nature of the event horizon. This is the central result of the present work. (author)

  6. Transcriptional profiling of radiation damage and preventive treatments in a 3-dimensional (3D) human cell culture model of oral mucositis.

    Lambros, Maria P; DeSalvo, Michael K; Moreno, Jonathan; Mulamalla, Hari Chandana; Kondapalli, Lavanya

    2015-12-01

    Cancer patients who receive radiation are often afflicted by oral mucositis, a debilitating disease, characterized by mouth sores and difficulty in swallowing. Oftentimes, cancer patients afflicted with mucositis must stop life-saving therapies. Thus it is very important to prevent mucositis before it develops. Using a validated organotypic model of human oral mucosa, a 3-dimensional cell culture model of human oral keratinocytes, it has been shown that a mixture (NAC-QYD) of N-acetyl cysteine (NAC) and a traditional Chinese medicine, Qingre Liyan decoction (QYD), prevented radiation damage (Lambros et al., 2014). Here we provide detailed methods and analysis of microarray data for non-irradiated and irradiated human oral mucosal tissue with and without pretreatment with NAC, QYD and NAC-QYD. The microarray data been deposited in Gene Expression Omnibus (GEO): GSE62397. These data can be used to further elucidate the mechanisms of irradiation damage in oral mucosa and its prevention. PMID:26697327

  7. Transcriptional profiling of radiation damage and preventive treatments in a 3-dimensional (3D human cell culture model of oral mucositis

    Maria P. Lambros

    2015-12-01

    Full Text Available Cancer patients who receive radiation are often afflicted by oral mucositis, a debilitating disease, characterized by mouth sores and difficulty in swallowing. Oftentimes, cancer patients afflicted with mucositis must stop life-saving therapies. Thus it is very important to prevent mucositis before it develops. Using a validated organotypic model of human oral mucosa, a 3-dimensional cell culture model of human oral keratinocytes, it has been shown that a mixture (NAC–QYD of N-acetyl cysteine (NAC and a traditional Chinese medicine, Qingre Liyan decoction (QYD, prevented radiation damage (Lambros et al., 2014. Here we provide detailed methods and analysis of microarray data for non-irradiated and irradiated human oral mucosal tissue with and without pretreatment with NAC, QYD and NAC-QYD. The microarray data been deposited in Gene Expression Omnibus (GEO: GSE62397. These data can be used to further elucidate the mechanisms of irradiation damage in oral mucosa and its prevention.

  8. 3-dimensional polymer gel dosimetry

    Recently developed techniques in conformal radiotherapy demand special properties of radiation dosimeters. Polymer gel dosimeter evaluated by nuclear magnetic resonance (NMR) is promising tool which can be used for measuring rather complicated 3-dimensional dose distributions with required precision of ± 5 %. This system is based on radiation-induced polymerisation and cross-linking of acrylic monomers which are uniformly dispersed in aqueous gel. The formation of cross-linked polymers in the irradiated regions of the gel increases the NMR relaxation rates of neighbouring water protons. BANG-2 type polymer gel was prepared. The composition of gel dosimeter was as follows: 3 % N,N'-methylene-bisacrylamide, 3 % acrylic acid, 1 % sodium hydroxide, 5 % gelatine, and 88 % water, where all percentages are by weight. The dosimeters in glass vessels were homogeneously irradiated by 60Co gamma photons in a Gammacell 220 unit and by 4 MV, 6 MV and 18 MV X ray photons on Varian Clinac 600C and 2100 C linear accelerators by doses in the range of 0-50 Gy. Evaluation of dosimeters was performed on Siemens EXPERT 1 T and Siemens VISION 1,5 T scanners. Multi-echo CPMG sequence with 16 echoes was used for the evaluation of T2-relaxation times in irradiated gel dosimeters. The dependence of 1/T2 response of dosimeters was studied on following factors: absorbed dose, energy of applied radiation, temperature during NMR evaluation, time since irradiation to NMR evaluation and strength of the magnetic field. An exponential dependence of 1/T2 response on absorbed dose in the range of 0-50 Gy was observed, in the range 0-10 Gy the data could be fitted by a linear function. There was observed no dependence of 1/T2 response on: energy (for three different photon energies used in this study), strength of magnetic field of NMR scanner, time from irradiation of the dosimeters to NMR evaluation. Increase of gel dosimeter 1/T2 response with the decrease of the temperature during NMR evaluation

  9. Conformal radiation therapy: technical requirements and clinical applications

    Conformal radiation therapy represents a considerable and attractive challenge in oncology. Its aim is mainly to improve local control by increasing the dose with an acceptable rate of complications. This work overviews the world literature on this subject. The technical and theoretical requirements are highlighted. These requirements include a precise definition of the target volume by digital imaging (essentially CT scan), but also clear view of the target volume and the organs at risk, a specific collimation of the beam, 3-D dose calculations, optimization procedures, and a rigid immobilization of the patient with verification of his position. Moreover, the clinical applications of conformal radiation therapy are reviewed and discussed. (authors). 80 refs., 1 tab

  10. Estimation of the mediastinal involvement probability in non-small cell lung cancer: a statistical definition of the clinical target volume for 3-dimensional conformal radiotherapy?

    Purpose. - Conformal irradiation of non-small cell lung carcinoma (NSCLC) is largely based on a precise definition of the nodal clinical target volume (CTVn). The reduction of the number of nodal stations to be irradiated would render tumor dose escalation more achievable. The aim of this work was to design an mathematical tool based on documented data, that would predict the risk of metastatic involvement for each nodal station. Methods and material. - From the large surgical series published in the literature we looked at the main pre-treatment parameters that modify the risk of nodal invasion. The probability of involvement for the 17 nodal stations described by the American Thoracic Society (ATS) was computed from all these publications and then weighted according to the French epidemiological data. Starting from the primitive location of the tumour as the main characteristic, we built a probabilistic tree for each nodal station representing the risk distribution as a function of each tumor feature. From the statistical point of view, we used the inversion of probability trees method described by Weinstein and Feinberg. Results. -Taking into account all the different parameters of I the pre-treatment staging relative to each level of the ATS map brings up to 20,000 different combinations. The first chosen parameters in the tree were, depending on the tumour location, the histological classification, the metastatic stage, the nodal stage weighted in function of the sensitivity and specificity of the diagnostic examination used (PET scan, CAT scan) and the tumoral stage. A software is proposed to compute a predicted probability of involvement of each nodal station for any given clinical presentation.Conclusion. -To better define the CTVn in NSCLC 3DRT, we propose a software that evaluates the mediastinal nodal involvement risk from easily accessible individual pretreatment parameters. (authors)

  11. Radiatively induced breaking of conformal symmetry in a superpotential

    Arbuzov, A. B.; Cirilo-Lombardo, D. J.

    2016-07-01

    Radiatively induced symmetry breaking is considered for a toy model with one scalar and one fermion field unified in a superfield. It is shown that the classical quartic self-interaction of the superfield possesses a quantum infrared singularity. Application of the Coleman-Weinberg mechanism for effective potential leads to the appearance of condensates and masses for both scalar and fermion components. That induces a spontaneous breaking of the initial classical symmetries: the supersymmetry and the conformal one. The energy scales for the scalar and fermion condensates appear to be of the same order, while the renormalization scale is many orders of magnitude higher. A possibility to relate the considered toy model to conformal symmetry breaking in the Standard Model is discussed.

  12. Radiatively Induced Breaking of Conformal Symmetry in a Superpotential

    Arbuzov, A B

    2015-01-01

    Radiatively induced symmetry breaking is considered for a toy model with one scalar and one fermion field unified in a superfield. It is shown that the classical quartic self-interaction of the superfield possesses a quantum infrared singularity. Application of the Coleman-Weinberg mechanism for effective potential leads to the appearance of condensates and masses for both scalar and fermion components. That induces a spontaneous breaking of the initial classical symmetries: the supersymmetry and the conformal one. The energy scales for the scalar and fermion condensates appear to be of the same order, while the renormalization scale is many orders of magnitude higher. A possibility to relate the considered toy model to conformal symmetry breaking in the Standard Model is discussed.

  13. Classically conformal radiative neutrino model with gauged B - L symmetry

    Okada, Hiroshi; Orikasa, Yuta

    2016-09-01

    We propose a classically conformal model in a minimal radiative seesaw, in which we employ a gauged B - L symmetry in the standard model that is essential in order to work the Coleman-Weinberg mechanism well that induces the B - L symmetry breaking. As a result, nonzero Majorana mass term and electroweak symmetry breaking simultaneously occur. In this framework, we show a benchmark point to satisfy several theoretical and experimental constraints. Here theoretical constraints represent inert conditions and Coleman-Weinberg condition. Experimental bounds come from lepton flavor violations (especially μ → eγ), the current bound on the Z‧ mass at the CERN Large Hadron Collider, and neutrino oscillations.

  14. Phantom dosimetry at 15 MV conformal radiation therapy

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  15. Phantom dosimetry at 15 MV conformal radiation therapy

    Thompson, Larissa; Campos, Tarcisio P.R., E-mail: larissathompson@hotmail.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Minas Gerais, MG (Brazil). Dept. de Engenharia Nuclear; Dias, Humberto G., E-mail: fisicamedica.hl@mariopenna.org.br [Instituto Mario Penna, Minas Gerais, MG (Brazil). Hospital Luxemburgo

    2013-07-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  16. Phantom dosimetry at 15 MV conformal radiation therapy

    Thompson, Larissa; Campos, Tarcisio P.R., E-mail: larissathompson@hotmail.com, E-mail: tprcampos@yahoo.com.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento de Engenharia Nuclear; Dias, Humberto G., E-mail: fisicamedica.hl@mariopenna.org.br [Luxemburgo Hospital, Mario Penna Institute, Belo Horizonte, MG (Brazil)

    2015-07-01

    The main goal of this work was to evaluate the spatial dose distribution into a tumor simulator inside a head phantom exposed to a 15MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. As final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols. (author)

  17. Conformal proton radiation therapy for pediatric low-grade astrocytomas

    Background: To evaluate the safety and efficacy of proton radiation therapy (PRT) for intracranial low-grade astrocytomas, the authors analyzed the first 27 pediatric patients treated at Loma Linda University Medical Center (LLUMC). Patients and Method: Between September 1991 and August 1997, 27 patients (13 female, 14 male) underwent fractionated proton radiation therapy for progressive or recurrent low-grade astrocytoma. Age at time of treatment ranged from 2 to 18 years (mean: 8.7 years). Tumors were located centrally (diencephatic) in 15 patients, in the cerebral and cerebellar hemispheres in seven patients, and in the brainstem in five patients. 25/27 patients (92%) were treated for progressive, unresectable, or residual disease following subtotal resection. Tissue diagnosis was available in 23/27 patients (85%). Four patients with optic pathway tumors were treated without histologic confirmation. Target doses between 50.4 and 63.0 CGE (cobalt gray equivalent, mean: 55.2 CGE) were prescribed at 1.8 CGE per fraction, five treatments per week. Results: At a mean follow-up period of 3.3 years (0.6-6.8 years), 6/27 patients experienced local failure (all located within the irradiated field), and 4/27 patients had died. By anatomic site these data translated into rates of local control and survival of 87% (13/15 patients) and 93% (14/15 patients) for central tumors, 71% (5/7 patients) and 86% (6/7 patients) for hemispheric tumors, and 60% (3/5 patients) and 60% (3/5 patients) for tumors located in the brainstem. Proton radiation therapy was generally well tolerated. All children with local control maintained their performance status. One child with associated neurofibromatosis, Type 1, developed Moyamoya disease. All six patients with optic pathway tumors and useful vision maintained or improved their visual status. Conclusions: This report on pediatric low-grade astrocytomas confirms proton radiation therapy as a safe and efficacious 3-D conformal treatment

  18. 3-Dimensional Magnetic Resonance Spectroscopic Imaging at 3 Tesla for Early Response Assessment of Glioblastoma Patients During External Beam Radiation Therapy

    Purpose: To evaluate the utility of 3-dimensional magnetic resonance (3D-MR) proton spectroscopic imaging for treatment planning and its implications for early response assessment in glioblastoma multiforme. Methods and Materials: Eighteen patients with newly diagnosed, histologically confirmed glioblastoma had 3D-MR proton spectroscopic imaging (MRSI) along with T2 and T1 gadolinium-enhanced MR images at simulation and at boost treatment planning after 17 to 20 fractions of radiation therapy. All patients received standard radiation therapy (RT) with concurrent temozolomide followed by adjuvant temozolomide. Imaging for response assessment consisted of MR scans every 2 months. Progression-free survival was defined by the criteria of MacDonald et al. MRSI images obtained at initial simulation were analyzed for choline/N-acetylaspartate ratios (Cho/NAA) on a voxel-by-voxel basis with abnormal activity defined as Cho/NAA ≥2. These images were compared on anatomically matched MRSI data collected after 3 weeks of RT. Changes in Cho/NAA between pretherapy and third-week RT scans were tested using Wilcoxon matched-pairs signed rank tests and correlated with progression-free survival, radiation dose and location of recurrence using Cox proportional hazards regression. Results: After a median follow-up time of 8.6 months, 50% of patients had experienced progression based on imaging. Patients with a decreased or stable mean or median Cho/NAA values had less risk of progression (P<.01). Patients with an increase in mean or median Cho/NAA values at the third-week RT scan had a significantly greater chance of early progression (P<.01). An increased Cho/NAA at the third-week MRSI scan carried a hazard ratio of 2.72 (95% confidence interval, 1.10-6.71; P=.03). Most patients received the prescription dose of RT to the Cho/NAA ≥2 volume, where recurrence most often occurred. Conclusion: Change in mean and median Cho/NAA detected at 3 weeks was a significant predictor of

  19. 3-Dimensional Magnetic Resonance Spectroscopic Imaging at 3 Tesla for Early Response Assessment of Glioblastoma Patients During External Beam Radiation Therapy

    Muruganandham, Manickam; Clerkin, Patrick P. [Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa (United States); Smith, Brian J. [Department of Biostatistics, University of Iowa Hospitals and Clinics, Iowa City, Iowa (United States); Anderson, Carryn M.; Morris, Ann [Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa (United States); Capizzano, Aristides A.; Magnotta, Vincent [Department of Radiology, University of Iowa Hospitals and Clinics, Iowa City, Iowa (United States); McGuire, Sarah M.; Smith, Mark C.; Bayouth, John E. [Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa (United States); Buatti, John M., E-mail: john-buatti@uiowa.edu [Department of Radiation Oncology, University of Iowa Hospitals and Clinics, Iowa City, Iowa (United States)

    2014-09-01

    Purpose: To evaluate the utility of 3-dimensional magnetic resonance (3D-MR) proton spectroscopic imaging for treatment planning and its implications for early response assessment in glioblastoma multiforme. Methods and Materials: Eighteen patients with newly diagnosed, histologically confirmed glioblastoma had 3D-MR proton spectroscopic imaging (MRSI) along with T2 and T1 gadolinium-enhanced MR images at simulation and at boost treatment planning after 17 to 20 fractions of radiation therapy. All patients received standard radiation therapy (RT) with concurrent temozolomide followed by adjuvant temozolomide. Imaging for response assessment consisted of MR scans every 2 months. Progression-free survival was defined by the criteria of MacDonald et al. MRSI images obtained at initial simulation were analyzed for choline/N-acetylaspartate ratios (Cho/NAA) on a voxel-by-voxel basis with abnormal activity defined as Cho/NAA ≥2. These images were compared on anatomically matched MRSI data collected after 3 weeks of RT. Changes in Cho/NAA between pretherapy and third-week RT scans were tested using Wilcoxon matched-pairs signed rank tests and correlated with progression-free survival, radiation dose and location of recurrence using Cox proportional hazards regression. Results: After a median follow-up time of 8.6 months, 50% of patients had experienced progression based on imaging. Patients with a decreased or stable mean or median Cho/NAA values had less risk of progression (P<.01). Patients with an increase in mean or median Cho/NAA values at the third-week RT scan had a significantly greater chance of early progression (P<.01). An increased Cho/NAA at the third-week MRSI scan carried a hazard ratio of 2.72 (95% confidence interval, 1.10-6.71; P=.03). Most patients received the prescription dose of RT to the Cho/NAA ≥2 volume, where recurrence most often occurred. Conclusion: Change in mean and median Cho/NAA detected at 3 weeks was a significant predictor of

  20. 3 - Dimensional Body Measurement Technology

    ZHOU Xu-dong; LI Yan-mei

    2002-01-01

    3 - dimensional body measurement technology, the basis of developing high technology in industry, accelerates digital development of aplparel industry. This paper briefly introduces the history of 3 - dimensional body measurement technology, and recounts the principle and primary structure of some types of 3 - dimensional automatic body measurement system. With this understanding, it discusses prospect of 3- dimensional CAD and virtual technology used in apparel industry.

  1. Dependence of Coronary 3-Dimensional Dose Maps on Coronary Topologies and Beam Set in Breast Radiation Therapy: A Study Based on CT Angiographies

    Moignier, Alexandra, E-mail: alexandra.moignier@gmail.com [Institut de Radioprotection et de Sûreté Nucléaire, PRP-HOM/SDI/LEDI, Laboratoire d' Evaluation de la Dose Interne, Fontenay-aux-Roses (France); Broggio, David [Institut de Radioprotection et de Sûreté Nucléaire, PRP-HOM/SDI/LEDI, Laboratoire d' Evaluation de la Dose Interne, Fontenay-aux-Roses (France); Derreumaux, Sylvie [Institut de Radioprotection et de Sûreté Nucléaire, PRP-HOM/SER/UEM, Unité d' Expertise en radioprotection Médicale, Fontenay-aux-Roses (France); El Baf, Fida [Institut de Radioprotection et de Sûreté Nucléaire, PRP-HOM/SDI/LEDI, Laboratoire d' Evaluation de la Dose Interne, Fontenay-aux-Roses (France); Mandin, Anne-Marie [Groupe Hospitalier Pitié-Salpêtrière, Assistance Publique - Hôpitaux de Paris, Service de Radiothérapie Oncologique, Paris (France); Girinsky, Théodore [Institut Gustave Roussy, Service de Radiothérapie Oncologique, Villejuif (France); Paul, Jean-François [Centre Chirurgical Marie-Lannelongue, Service de Radiologie, Le Plessis-Robinson (France); and others

    2014-05-01

    Purpose: In left-side breast radiation therapy (RT), doses to the left main (LM) and left anterior descending (LAD) coronary arteries are usually assessed after delineation by prior anatomic knowledge on the treatment planning computed tomography (CT) scan. In this study, dose sensitivity due to interindividual coronary topology variation was assessed, and hot spots were located. Methods and Materials: Twenty-two detailed heart models, created from heart computed tomography angiographies, were fitted into a single representative female thorax. Two breast RT protocols were then simulated into a treatment planning system: the first protocol comprised tangential and tumoral bed beams (TGs{sub T}B) at 50 + 16 Gy, the second protocol added internal mammary chain beams at 50 Gy to TGs{sub T}B (TGs{sub T}B{sub I}MC). For the heart, the LAD, and the LM, several dose indicators were calculated: dose-volume histograms, mean dose (D{sub mean}), minimal dose received by the most irradiated 2% of the volume (D{sub 2%}), and 3-dimensional (3D) dose maps. Variations of these indicators with anatomies were studied. Results: For the LM, the intermodel dispersion of D{sub mean} and D{sub 2%} was 10% and 11%, respectively, with TGs{sub T}B and 40% and 80%, respectively, with TGs{sub T}B{sub I}MC. For the LAD, these dispersions were 19% (D{sub mean}) and 49% (D{sub 2%}) with TGs{sub T}B and 35% (D{sub mean}) and 76% (D{sub 2%}) with TGs{sub T}B{sub I}MC. The 3D dose maps revealed that the internal mammary chain beams induced hot spots between 20 and 30 Gy on the LM and the proximal LAD for some coronary topologies. Without IMC beams, hot spots between 5 and 26 Gy are located on the middle and distal LAD. Conclusions: Coronary dose distributions with hot spot location and dose level can change significantly depending on coronary topology, as highlighted by 3D coronary dose maps. In clinical practice, coronary imaging may be required for a relevant coronary dose assessment

  2. Dependence of Coronary 3-Dimensional Dose Maps on Coronary Topologies and Beam Set in Breast Radiation Therapy: A Study Based on CT Angiographies

    Purpose: In left-side breast radiation therapy (RT), doses to the left main (LM) and left anterior descending (LAD) coronary arteries are usually assessed after delineation by prior anatomic knowledge on the treatment planning computed tomography (CT) scan. In this study, dose sensitivity due to interindividual coronary topology variation was assessed, and hot spots were located. Methods and Materials: Twenty-two detailed heart models, created from heart computed tomography angiographies, were fitted into a single representative female thorax. Two breast RT protocols were then simulated into a treatment planning system: the first protocol comprised tangential and tumoral bed beams (TGsTB) at 50 + 16 Gy, the second protocol added internal mammary chain beams at 50 Gy to TGsTB (TGsTBIMC). For the heart, the LAD, and the LM, several dose indicators were calculated: dose-volume histograms, mean dose (Dmean), minimal dose received by the most irradiated 2% of the volume (D2%), and 3-dimensional (3D) dose maps. Variations of these indicators with anatomies were studied. Results: For the LM, the intermodel dispersion of Dmean and D2% was 10% and 11%, respectively, with TGsTB and 40% and 80%, respectively, with TGsTBIMC. For the LAD, these dispersions were 19% (Dmean) and 49% (D2%) with TGsTB and 35% (Dmean) and 76% (D2%) with TGsTBIMC. The 3D dose maps revealed that the internal mammary chain beams induced hot spots between 20 and 30 Gy on the LM and the proximal LAD for some coronary topologies. Without IMC beams, hot spots between 5 and 26 Gy are located on the middle and distal LAD. Conclusions: Coronary dose distributions with hot spot location and dose level can change significantly depending on coronary topology, as highlighted by 3D coronary dose maps. In clinical practice, coronary imaging may be required for a relevant coronary dose assessment, especially in cases of internal mammary chain irradiation

  3. Three dimensional conformal radiation therapy in pediatric parameningeal rhabdomyosarcomas

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

  4. Feasibility and acute toxicity of 3-dimensional conformal external-beam accelerated partial-breast irradiation for early-stage breast cancer after breast-conserving surgery in Chinese female patients

    LI Feng-yan; HE Zhen-yu; XUE Ming; CHEN Li-xin; WU San-gang; GUAN Xun-xing

    2011-01-01

    Background A growing number of studies worldwide have advocated the replacement of whole-breast irradiation with accelerated partial breast irradiation using three-dimensional conformal external-beam radiation (APBI-3DCRr) for early-stage breast cancer. But APBI can be only used in selected population of patients with early-staged breast cancer. It is not replacing the whole breast radiotherapy. This study aimed to examine the feasibility and acute normal tissue toxicity of the APBI-3DCRT technique in Chinese female patients who generally have smaller breasts compared to their Western counterparts.Methods From May 2006 to December 2009, a total of 48 Chinese female patients (with early-stage breast cancer who met the inclusion criteria) received APBI-3DCRT after breast-conserving surgery at Sun Yat-sen University Cancer Center. The total dosage from APBI-3DCRT was 34 Gy, delivered in 3.4 Gy per fractions, twice per day at intervals of at least six hours. The radiation dose, volume of the target area and volume of irradiated normal tissues were calculated.Acute toxicity was evaluated according to the Common Toxicity Criteria (CTC) 3.0.Results Among the 48 patients, the planning target volume for evaluation (PTVE) was (90.42±9.26) cm3, the ipsilateral breast volume (IBV) was (421.74±28.53) cm3, and the ratio between the two was (20.74±5.86)%. Evaluation of the dosimetric characteristics of the PTVE revealed excellent dosimetric results in 14 patients and acceptable results in 34 patients. The dose delivered to the PTVE ranged from 93% to 110% of the prescribed dose. The average ratio of the volume of PTVE receiving 95% of the prescription dose (V95) was (99.26±0.37)%. The habituation index (HI) and the conformity index (CI) were 1.08±0.01 and 0.72±0.02, respectively, suggesting good homogeneity and conformity of the dose delivered to the target field. The radiation dose to normal tissues and organs was within the dose limitation.Subjects experienced mild acute

  5. Application of modified dynamic conformal arc (MDCA) technique on liver stereotactic body radiation therapy (SBRT) planning following RTOG 0438 guideline

    Shi, Chengyu, E-mail: shicy1974@yahoo.com; Chen, Yong; Fang, Deborah; Iannuzzi, Christopher

    2015-04-01

    Liver stereotactic body radiation therapy (SBRT) is a feasible treatment method for the nonoperable, patient with early-stage liver cancer. Treatment planning for the SBRT is very important and has to consider the simulation accuracy, planning time, treatment efficiency effects etc. The modified dynamic conformal arc (MDCA) technique is a 3-dimensional conformal arc planning method, which has been proposed for liver SBRT planning at our center. In this study, we compared the MDCA technique with the RapidArc technique in terms of planning target volume (PTV) coverage and sparing of organs at risk (OARs). The results show that the MDCA technique has comparable plan quality to RapidArc considering PTV coverage, hot spots, heterogeneity index, and effective liver volume. For the 5 PTVs studied among 4 patients, the MDCA plan, when compared with the RapidArc plan, showed 9% more hot spots, more heterogeneity effect, more sparing of OARs, and lower liver effective volume. The monitor unit (MU) number for the MDCA plan is much lower than for the RapidArc plans. The MDCA plan has the advantages of less planning time, no-collision treatment, and a lower MU number.

  6. Conformal proton radiation therapy for pediatric low-grade astrocytomas

    Hug, E.B. [Loma Linda Univ. Medical Center, Loma Linda, CA (United States). Dept. of Radiation Medicine; Loma Linda Univ. Medical Center, Loma Linda, CA (United States). Dept. of Pediatrics and Dept. of Pathology; Darthmouth-Hitchcock Medical Center, Lebanon, New Hampshire (United States). Section of Radiation Oncology; Muenter, M.W.; Archambeau, J.O.; DeVries, A.; Loredo, L.N.; Grove, R.I.; Slater, J.D. [Loma Linda Univ. Medical Center, Loma Linda, CA (United States). Dept. of Radiation Medicine; Liwnicz, B. [Loma Linda Univ. Medical Center, Loma Linda, CA (United States). Dept. of Pathology

    2002-01-01

    Background: To evaluate the safety and efficacy of proton radiation therapy (PRT) for intracranial low-grade astrocytomas, the authors analyzed the first 27 pediatric patients treated at Loma Linda University Medical Center (LLUMC). Patients and Method: Between September 1991 and August 1997, 27 patients (13 female, 14 male) underwent fractionated proton radiation therapy for progressive or recurrent low-grade astrocytoma. Age at time of treatment ranged from 2 to 18 years (mean: 8.7 years). Tumors were located centrally (diencephatic) in 15 patients, in the cerebral and cerebellar hemispheres in seven patients, and in the brainstem in five patients. 25/27 patients (92%) were treated for progressive, unresectable, or residual disease following subtotal resection. Tissue diagnosis was available in 23/27 patients (85%). Four patients with optic pathway tumors were treated without histologic confirmation. Target doses between 50.4 and 63.0 CGE (cobalt gray equivalent, mean: 55.2 CGE) were prescribed at 1.8 CGE per fraction, five treatments per week. Results: At a mean follow-up period of 3.3 years (0.6-6.8 years), 6/27 patients experienced local failure (all located within the irradiated field), and 4/27 patients had died. By anatomic site these data translated into rates of local control and survival of 87% (13/15 patients) and 93% (14/15 patients) for central tumors, 71% (5/7 patients) and 86% (6/7 patients) for hemispheric tumors, and 60% (3/5 patients) and 60% (3/5 patients) for tumors located in the brainstem. Proton radiation therapy was generally well tolerated. All children with local control maintained their performance status. One child with associated neurofibromatosis, Type 1, developed Moyamoya disease. All six patients with optic pathway tumors and useful vision maintained or improved their visual status. Conclusions: This report on pediatric low-grade astrocytomas confirms proton radiation therapy as a safe and efficacious 3-D conformal treatment

  7. Usefulness of 3D conformal radiation therapy for reduction of radiation-induced white matter injury

    The usefulness of three-dimensional conformal radiation therapy (3DCRT) in decreasing radiation-induced white matter changes (WMC) was assessed. Thirty-seven patients (age 5-77 years, mean 42 years; male/female=11/26) with primary intracranial tumors received 40 Gy or more, and were followed up with MRI for more than one year. Thirty-four patients underwent chemotherapy (with a platinum drug, 16; without a platinum drug, 18). Nineteen were treated with 3DCRT (radiation dose, range 60-64 Gy, mean 60.2 Gy; maximum width of radiation field, range 7-16 cm, mean 12.5 cm) and 18 were treated with non-3DCRT (radiation dose, range 40-62.4 Gy, mean 53.4 Gy; maximum width of radiation field, range 4-19 cm, mean 12.3 cm). WMC occurred in 37% of the 3DCRT group and 50% of the non-3DCRT group. Among the patients with WMC, Karnofsky performance scale (KPS) deteriorated in none of the 3DCRT group, whereas KPS deteriorated in 3 of 9 in the non-3DCRT group. All the patients with deterioration of KPS were at least 50 years of age. KPS did not strictly correlate with the severity of white matter changes on MRI. Chemotherapy with a platinum drug increased the incidence of WMC. Age (<50 years vs. ≥50 years), gender, radiation technique (3DCRT vs. non-3DCRT), radiation dose (<60 Gy vs. ≥60 Gy), maximum field-size (<12 cm vs. ≥12 cm), and maximum boost-field size (<10 cm vs. ≥10 cm) were not relevant to the incidence and severity of WMC. Though 3DCRT did not decrease the incidence and severity of white matter change on MRI, it may be useful to preserve the KPS, especially for older patients. (author)

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

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

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

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

    2013-12-15

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

  10. Transitioning from 2-D Radiation Therapy to 3-D Conformal Radiation Therapy and Intensity Modulated Radiation Therapy: Training Material

    The technology of radiation oncology has advanced very rapidly in recent years. However, the sophistication of technology available in individual radiation therapy centres varies dramatically throughout the world. Treatment capabilities with planar imaging and limited cross-sectional imaging support have been labelled as two dimensional radiation therapy (2-D RT). With increased use of more advanced cross-sectional imaging, the introduction of more complex dose calculation capabilities for treatment planning and more sophisticated treatment delivery procedures, three dimensional conformal radiation therapy (3-D CRT) can be provided. Further sophistication in treatment planning and treatment delivery capabilities enables intensity modulated radiation therapy (IMRT). Recognizing that huge disparities exist across the world, and in an attempt to aid in advancing institutional capabilities, the IAEA published ‘Transition from 2-D Radiotherapy to 3-D Conformal and Intensity Modulated Radiotherapy’ (IAEA-TECDOC-1588) in May 2008. Divided into two parts — on CRT and on IMRT — the publication provides guidelines on the transition from 2-D RT through 3-D CRT to IMRT. It is recognized that 3-D CRT is the standard of care in most radiation treatment processes and that IMRT technologies are still evolving. The publication provides clear guidelines and highlights the milestones to be achieved when transitioning from 2-D RT to 3-D CRT and IMRT. While IAEA-TECDOC-1588 provides comprehensive guidelines and milestones, the present publication provides training materials to aid professionals in the continuing education required for the implementation of more advanced treatment capabilities, especially 3-D CRT. These materials are based on the results of two consultants meetings organized by the IAEA in 2009 and 2010, primarily focused on providing guidance on what training materials were available or needed to be developed, with a special emphasis on transitioning from 2-D

  11. Regional cancer centre demonstrates voluntary conformity with the national Radiation Oncology Practice Standards

    Manley, Stephen, E-mail: stephen.manley@ncahs.health.nsw.gov.au; Last, Andrew; Fu, Kenneth; Greenham, Stuart; Kovendy, Andrew; Shakespeare, Thomas P [North Coast Cancer Institute, Lismore, New South Wales (Australia)

    2015-06-15

    Radiation Oncology Practice Standards have been developed over the last 10 years and were published for use in Australia in 2011. Although the majority of the radiation oncology community supports the implementation of the standards, there has been no mechanism for uniform assessment or governance. North Coast Cancer Institute's public radiation oncology service is provided across three main service centres on the north coast of NSW. With a strong focus on quality management, we embraced the opportunity to demonstrate conformity with the Radiation Oncology Practice Standards. The Local Health District's Clinical Governance units were engaged to perform assessments of our conformity with the standards and this was signed off as complete on 16 December 2013. The process of demonstrating conformity with the Radiation Oncology Practice Standards has enhanced the culture of quality in our centres. We have demonstrated that self-assessment utilising trained auditors is a viable method for centres to demonstrate conformity. National implementation of the Radiation Oncology Practice Standards will benefit individual centres and the broader radiation oncology community to improve the service delivered to our patients.

  12. Regional cancer centre demonstrates voluntary conformity with the national Radiation Oncology Practice Standards

    Radiation Oncology Practice Standards have been developed over the last 10 years and were published for use in Australia in 2011. Although the majority of the radiation oncology community supports the implementation of the standards, there has been no mechanism for uniform assessment or governance. North Coast Cancer Institute's public radiation oncology service is provided across three main service centres on the north coast of NSW. With a strong focus on quality management, we embraced the opportunity to demonstrate conformity with the Radiation Oncology Practice Standards. The Local Health District's Clinical Governance units were engaged to perform assessments of our conformity with the standards and this was signed off as complete on 16 December 2013. The process of demonstrating conformity with the Radiation Oncology Practice Standards has enhanced the culture of quality in our centres. We have demonstrated that self-assessment utilising trained auditors is a viable method for centres to demonstrate conformity. National implementation of the Radiation Oncology Practice Standards will benefit individual centres and the broader radiation oncology community to improve the service delivered to our patients

  13. A conformal approach for the analysis of the non-linear stability of radiation cosmologies

    Luebbe, Christian, E-mail: c.luebbe@ucl.ac.uk [Department of Mathematics, University College London, Gower Street, London, WC1E 6BT (United Kingdom); Department of Mathematics, University of Leicester, University Road, LE1 8RH (United Kingdom); Valiente Kroon, Juan Antonio, E-mail: j.a.valiente-kroon@qmul.ac.uk [School of Mathematical Sciences, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom)

    2013-01-15

    The conformal Einstein equations for a trace-free (radiation) perfect fluid are derived in terms of the Levi-Civita connection of a conformally rescaled metric. These equations are used to provide a non-linear stability result for de Sitter-like trace-free (radiation) perfect fluid Friedman-Lemaitre-Robertson-Walker cosmological models. The solutions thus obtained exist globally towards the future and are future geodesically complete. - Highlights: Black-Right-Pointing-Pointer We study the Einstein-Euler system in General Relativity using conformal methods. Black-Right-Pointing-Pointer We analyze the structural properties of the associated evolution equations. Black-Right-Pointing-Pointer We establish the non-linear stability of pure radiation cosmological models.

  14. Radiation dosimetry predicts IQ after conformal radiation therapy in pediatric patients with localized ependymoma

    Purpose: To assess the effects of radiation dose-volume distribution on the trajectory of IQ development after conformal radiation therapy (CRT) in pediatric patients with ependymoma. Methods and Materials: The study included 88 patients (median age, 2.8 years ± 4.5 years) with localized ependymoma who received CRT (54-59.4 Gy) that used a 1-cm margin on the postoperative tumor bed. Patients were evaluated with tests that included IQ measures at baseline (before CRT) and at 6, 12, 24, 36, 48, and 60 months. Differential dose-volume histograms (DVH) were derived for total-brain, supratentorial-brain, and right and left temporal-lobe volumes. The data were partitioned into three dose intervals and integrated to create variables that represent the fractional volume that received dose over the specified intervals (e.g., V0-20Gy, V20-40Gy, V40-65Gy) and modeled with clinical variables to develop a regression equation to estimate IQ after CRT. Results: A total of 327 IQ tests were performed in 66 patients with infratentorial tumors and 20 with supratentorial tumors. The median follow-up was 29.4 months. For all patients, IQ was best estimated by age (years) at CRT; percent volume of the supratentorial brain that received doses between 0 and 20 Gy, 20 and 40 Gy, and 40 and 65 Gy; and time (months) after CRT. Age contributed significantly to the intercept (p > 0.0001), and the dose-volume coefficients were statistically significant (V0-20Gy, p = 0.01; V20-40Gy, p 40-65Gy, p = 0.04). A similar model was developed exclusively for patients with infratentorial tumors but not supratentorial tumors. Conclusion: Radiation dosimetry can be used to predict IQ after CRT in patients with localized ependymoma. The specificity of models may be enhanced by grouping according to tumor location

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

    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.

  16. Performances study of UWB monopole antennas using half-elliptic radiator conformed on elliptical surface

    Djidel, S.; Bouamar, M.; Khedrouche, D.

    2016-04-01

    This paper presents a performances study of UWB monopole antenna using half-elliptic radiator conformed on elliptical surface. The proposed antenna, simulated using microwave studio computer CST and High frequency simulator structure HFSS, is designed to operate in frequency interval over 3.1 to 40 GHz. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. The proposed antenna structure is suitable for ultra-wideband applications, which is, required for many wearable electronics applications.

  17. Preliminary analysis of a clinical trial for threedimensional conformal radiation therapy after conservative surgery

    Hui Yao; Jinlan Gong; Li Li; Yun Wang; Xiaofeng Wu; Kezhu Hou

    2012-01-01

    Objective: The aim of this study was to evaluate the efficacy, complications and cosmetic results of three-dimensional conformal radiation therapy for early breast cancer after conservative surgery. Methods: Among 80 patients, 44 were treated by modified radical mastectomy followed by adjuvant radiotherapy (modified radical mastectomy, MMT), 36 were treated with breast conservative surgery with adjuvant irradiation [breast-conservation therapy (BCT)]. Tangential fields were used to deliver 6 MV X-ray beams to a total dose of 50 Gy. Another 16 Gy was added to the tumor bed with 6-9 MeV electron beams for BCT. Results: In MMT group, the local control, metastasis-free and death were 41, 41 and 1 respectively; in BCT group, the local control, metastasis-free and death were 35, 35 and 0. The difference of the above two indicators between the two groups showeed no statistical insignificance (P > 0. 05). In MMT group, 32 patients suffer radiation dermatitis above 2-level, 12 patients suffer radiation pneumonia, and 10 patients suffer edema of illness-side upper extremity; in BCT group, the above indicators were only 6, 2 and 1 respectively. Three months, six months and one year after radiation therapy, 90%, 92% and 95% patients were assessed as excellence in fine cosmetic state in BCT group. Conclusion: The effects of threedimensional conformal radiation therapy after conservative surgery are the same as that of modified radical mastectomy, while the former has better cosmetic results and lower radiation therapy induced complications.

  18. Three-dimensional treatment planning and conformal radiation therapy: preliminary evaluation

    Preliminary clinical results are presented for 209 patients with cancer who had treatment planned on our three-dimensional radiation treatment planning (3-D RTP) system and were treated with external beam conformal radiation therapy. Average times (min) for CT volumetric simulation were: 74 without or 84 with contrast material; 36 for contouring of tumor/target volume and 44 for normal anatomy; 78 for treatment planning; 53 for plan evaluation/optimization; and 58 for verification simulation. Average time of daily treatment sessions with 3-D conformal therapy or standard techniques was comparable for brain, head and neck, thoracic, and hepatobiliary tumors (11.8-14 min and 11.5-12.1, respectively). For prostate cancer patients treated with 3-D conformal technique and Cerrobend blocks, mean treatment time was 19 min; with multileaf collimation it was 14 min and with bilateral arc rotation, 9.8 min. Acute toxicity was comparable to or lower than with standard techniques. Sophisticated 3-D RTP and conformal irradiation can be performed in a significant number of patients at a reasonable cost. Further efforts, including dose-escalation studies, are necessary to develop more versatile and efficient 3-D RTP systems and to enhance the cost benefit of this technology in treatment of patients with cancer

  19. Late rectal symptoms and quality of life after conformal radiation therapy for prostate cancer

    Background and purpose: This study was carried out in order to analyze the prevalence of late rectal and anal symptoms after conformal radiation therapy for prostate cancer and to assess their association with quality of life. Patients and methods: Two-hundred and forty nine patients were interviewed at 24-111 months after definitive conformal radiation therapy of localized prostate cancer with a median dose of 70 Gy. Rectal symptoms and fecal incontinence were evaluated with standardized questionnaires. Quality of life was assessed with the EORTC Quality of Life Questionnaire-C30 and the prostate cancer module PR25. Results: Rectal symptoms were mostly intermittent. Daily symptoms occurred in ≤5% of the patients. Incontinence was mostly mild with only 3% of the patients reporting daily incontinence episodes. Quality of life was comparable to that of the male German general population except that cognitive functioning and diarrhea were worse in the study population and pain was worse in the reference population. Global quality of life was associated with fecal incontinence, fecal urge, tenesmus, therapy for rectal symptoms and hormonal therapy for biochemical/clinical recurrence. Conclusions: Rectal symptoms and fecal incontinence after conformal radiation therapy for prostate cancer are mostly intermittent. Fecal incontinence, fecal urge and tenesmus are associated with lower global quality of life levels

  20. Hypofractionation does not increase radiation pneumonitis risk with modern conformal radiation delivery techniques

    Vogelius, Ivan R; Westerly, David C; Cannon, George M;

    2010-01-01

    To study the interaction between radiation dose distribution and hypofractionated radiotherapy with respect to the risk of radiation pneumonitis (RP) estimated from normal tissue complication probability (NTCP) models.......To study the interaction between radiation dose distribution and hypofractionated radiotherapy with respect to the risk of radiation pneumonitis (RP) estimated from normal tissue complication probability (NTCP) models....

  1. DNA conformation of Chinese hamster V79 cells and sensitivity to ionizing radiation

    Chinese hamster V79 cells grown for 20 h in suspension culture form small clusters of cells (spheroids) which are more resistant to killing by ionizing radiation than V79 cells grown as monolayers. This resistance appears to be due to the greater capacity of cells grown in contact to repair radiation damage. Attempts to relate this ''contact effect'' to differences in DNA susceptibility or DNA repair capacity have provided conflicting results. Two techniques, alkaline sucrose gradient sedimentation and alkaline elution, show no difference in the amounts of radiation-induced DNA single-strand breakage or its repair between suspension or monolayer cells. However, using the alkali-unwinding assay, the rate of DNA unwinding is much slower for suspension cells than for monolayer cells. Interestingly, a decrease in salt concentration or in pH of the unwinding solution eliminates these differences in DNA unwinding kinetics. A fourth assay, sedimentation of nucleoids on neutral sucrose gradients, also shows a significant decrease in radiation damage produced in suspension compared to monolayer cultures. It is believed that this assay measures differences in DNA conformation (supercoiling) as well as differences in DNA strand breakage. We conclude from these four assays that the same number of DNA strand breaks/Gy is produced in monolayer and spheroid cells. However, changes in DNA conformation or packaging occur when cells are grown as spheroids, and these changes are responsible for reducing DNA damage by ionizing radiation

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

    To compare 3 Dimensional Conformal radiotherapy (3D-CRT) with Intensity Modulated Radiotherapy (IMRT) with Volumetric-Modulated Arc Therapy (VMAT) for bladder cancer. 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. 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 < 0.05). Average treatment delivery time were 2:25min (range 2:01–3:09) for 3D-CRT; 4:39 (range 3:41–6:40) for IMRT; and 1:14 (range 1:13–1:14) for VMAT. In selected patients, the SIB did not result in a higher dose to small bowel or rectum. 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

  3. 3-D-conformal radiation therapy for pediatric giant cell tumors of the skull base

    Hug, E.B. [Massachusetts General Hospital, Boston, MA (United States). Dept. of Radiation Oncology; Harvard Univ., Cambridge, MA (United States). Cyclotron Lab.; Dartmouth Hitchcock Medical Center, Lebanon, NH (United States). Section of Radiation Oncology; Muenter, M.W.; Vries, A. de [Massachusetts General Hospital, Boston, MA (United States). Dept. of Radiation Oncology; Adams, J.A.; Munzenrider, J.E. [Massachusetts General Hospital, Boston, MA (United States). Dept. of Radiation Oncology; Harvard Univ., Cambridge, MA (United States). Cyclotron Lab.; Rosenberg, A.E. [Massachusetts General Hospital, Boston, MA (United States). Dept. of Pathology

    2002-05-01

    Background: Giant cell tumors (GCT) of the base of skull are rare neoplasms. This report reviews the treatment of four pediatric patients presenting with aggressive giant cell tumor, using fractionated and combined, conformal proton and photon radiation therapy at Massachusetts General Hospital and Harvard Cyclotron Laboratory. Patients and Methods: Three female patients and one adolescent male, ages 10-15 years, had undergone prior, extensive surgical resection(s) and were treated for either primary (two patients) or recurrent (two patients) disease. Gross residual tumor was evident in three patients and microscopic disease suspected in one patient. Combined proton and photon radiation theory was based on three-dimensional (3-D) planning, consisting of fractionated treatment, one fraction per day at 1.8 CGE (cobalt-gray equivalent) to total target doses of 57.6, 57.6, 59.4, and 61.2 Gy/CGE. Results: With observation times of 3.1 years, 3.3, 5.3, and 5.8 years, all four patients were alive and well and remained locally controlled without evidence of recurrent disease. Except for one patient with partial pituitary insufficiency following radiotherapy for sellar recurrent disease, thus far no late effects attributable to radiation therapy have been observed. Conclusions: 3-D conformal radiation therapy offers a realistic chance of tumor control for aggressive giant cell tumor in the skull base, either postoperatively or at time of recurrence. Conformal treatment techniques allow the safe delivery of relatively high radiation doses in the pediatric patient without apparent increase of side effects. (orig.)

  4. Implementation of national radiation safety regulations in Sri Lanka: A beginning to conform to international standards

    The Atomic Energy Authority (AEA) of Sri Lanka was established in 1970 by the legislation Atomic Energy Authority Act No.19 of 1969. Since the act was enacted 03 decades ago, the recent advances and needs were not identified. The AEA was empowered to carry out promotional activities of nuclear technology as well as regulatory activities. Under the provisions made in the act the Atomic Energy Regulations of 1975 were promulgated to regulate the activities related to radiation in the country until year 2000. Having realized that these regulations are not sufficient to meet the current international requirements with the technological advances in the fields 'Ionizing Radiation Protection Regulations' which conforms to the IAEA's Basic Safety Standards-115 were promulgated in year 2000. Even though the new regulations were made under the same act, the AEA could achieve a positive improvement in regulatory activities in use of ionizing radiation in the country by establishing a good system for implementation of a notification, licensing, and inspection programmes to conform to the International requirements. Three codes of practices have been drafted and are under review and few manuals have been printed for distribution among the radiation users. Two regulations on safe transport of radioactive material and radioactive waste management have to be promulgated and steps have been initiated in this regard. Assistance from the IAEA was received to strengthen the regulatory infrastructure in Sri Lanka under the model project in radiation protection. Also IAEA has carried out several missions to assess the regulatory effectiveness in Sri Lanka. These missions state the successful achievement of milestones I and II of the IAEA model project on Strengthening and Harmonization of Radiation Protection. However it is identified that amendment of the act is a timely requirement for the effective independence of the regulatory activities carried out by the AEA. (author)

  5. Clinical outcome of three dimensional conformal radiation therapy for early breast cancer after conservative surgery

    Objective: To compare the efficacy, complications, cosmetic results between conventional radiotherapy (CR) and three dimensional conformal radiation therapy (3DCRT) after conservative surgery for early breast cancer. Methods: Totally 106 patients underwent postoperative radiotherapy after breast-conserving surgery, including 62 patients who received CR and 46 received 3DCRT. The radiation dose was determined by the tumor size, tumor location and axillary node involvement. Tangential fields were used to deliver 6 MV X-ray beams to a total dose of 50 Gy in 5 weeks. An additional 10-15 Gy was given to the tumor bed with 6-9 MeV electron beams in 1.0-1.5 weeks. The median follow-up time was 32 months. Results: The local recurrence, metastasis or death were observed in 3, 5 and 2 patients in the CR group, while 1, 4 and 2 in the 3DCRT group. No statistical significant difference was found between these two groups (P>0.05). Radiation induced pneumonia was observed in 11 patients in CR group versus none in the 3DCRT group. Six months and one year after radiotherapy, 90% and 93% of these patients were assessed as excellent or in fine cosmetic state in the CR group, versus 91.5% and 93.8% in the 3DCRT group. There was no significant difference in the cosmetic results between these two groups (P > 0.05). Conclusions: Three dimensional conformal radiation therapy possesses similar treatment and cosmetic results to conventional radiotherapy after conservative surgery for early breast cancer. But the former, one can markedly reduce the likely hood of radiation complications. (authors)

  6. Organs at risk and target volumes: Definition for conformal radiation therapy in breast cancer

    Adjuvant radiotherapy is a standard component of breast cancer treatment. The addition of radiotherapy after breast conserving surgery has been shown to reduce local recurrence rate and improve long-term survival. Accurate delineation of target volumes and organs at risk is crucial to the quality of treatment planning and delivered accomplished with innovate technologies in radiation therapy. This allows the radiation beam to be shaped specifically to each individual patient's anatomy. Target volumes include the mammary gland and surgical bed in case of breast conserving surgery, the chest wall in case of mastectomy, and if indicated, regional lymph nodes (axillary, supra- and infra-clavicular and internal mammary). Organs at risk include lungs, thyroid, brachial plexus, heart, spinal cord and oesophagus. The aim of this article is to encourage the use of conformal treatment and delineation of target volumes and organs at risk and to describe specifically the definition of these volumes. (authors)

  7. A 5-Year Investigation of Children's Adaptive Functioning Following Conformal Radiation Therapy for Localized Ependymoma

    Purpose: Conformal and intensity modulated radiation therapies have the potential to preserve cognitive outcomes in children with ependymoma; however, functional behavior remains uninvestigated. This longitudinal investigation prospectively examined intelligence quotient (IQ) and adaptive functioning during the first 5 years after irradiation in children diagnosed with ependymoma. Methods and Materials: The study cohort consisted of 123 children with intracranial ependymoma. Mean age at irradiation was 4.60 years (95% confidence interval [CI], 3.85-5.35). Serial neurocognitive evaluations, including an age-appropriate IQ measure and the Vineland Adaptive Behavior Scales (VABS), were completed before irradiation, 6 months after treatment, and annually for 5 years. A total of 579 neurocognitive evaluations were included in these analyses. Results: Baseline IQ and VABS were below normative means (P<.05), although within the average range. Linear mixed models revealed stable IQ and VABS across the follow-up period, except for the VABS Communication Index, which declined significantly (P=.015). Annual change in IQ (−.04 points) did not correlate with annual change in VABS (−.90 to +.44 points). Clinical factors associated with poorer baseline performance (P<.05) included preirradiation chemotherapy, cerebrospinal fluid shunt placement, number and extent of surgical resections, and younger age at treatment. No clinical factors significantly affected the rate of change in scores. Conclusions: Conformal and intensity modulated radiation therapies provided relative sparing of functional outcomes including IQ and adaptive behaviors, even in very young children. Communication skills remained vulnerable and should be the target of preventive and rehabilitative interventions.

  8. Radiation and scattering from cylindrically conformal printed antennas. Ph.D. Thesis Final Report

    Kempel, Leo C.; Volakis, John L.

    1994-01-01

    Microstrip patch antennas offer considerable advantages in terms of weight, aerodynamic drag, cost, flexibility, and observables over more conventional protruding antennas. These flat patch antennas were first proposed over thirty years ago by Deschamps in the United States and Gutton and Baisinot in France. Such antennas have been analyzed and developed for planar as well as curved platforms. However, the methods used in these designs employ gross approximations, suffer from extreme computational burden, or require expensive physical experiments. The goal of this thesis is to develop accurate and efficient numerical modeling techniques which represent actual antenna structures mounted on curved surfaces with a high degree of fidelity. In this thesis, the finite element method is extended to cavity-backed conformal antenna arrays embedded in a circular, metallic, infinite cylinder. Both the boundary integral and absorbing boundary mesh closure conditions will be used for terminating the mesh. These two approaches will be contrasted and used to study the scattering and radiation behavior of several useful antenna configurations. An important feature of this study will be to examine the effect of curvature and cavity size on the scattering and radiation properties of wraparound conformal antenna arrays.

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

    We report our experience of establishing planning objectives to achieve dose coverage, conformity, and dose falloff for spine stereotactic body radiation therapy (SBRT) plans. Patients with spine lesions were treated using SBRT in our institution since September 2009. Since September 2011, we established the following planning objectives for our SBRT spine plans in addition to the cord dose constraints: (1) dose coverage—prescription dose (PD) to cover at least 95% planning target volume (PTV) and 90% PD to cover at least 99% PTV; (2) conformity index (CI)—ratio of prescription isodose volume (PIV) to the PTV < 1.2; (3) dose falloff—ratio of 50% PIV to the PTV (R50%); (4) and maximum dose in percentage of PD at 2 cm from PTV in any direction (D2cm) to follow Radiation Therapy Oncology Group (RTOG) 0915. We have retrospectively reviewed 66 separate spine lesions treated between September 2009 and December 2012 (31 treated before September 2011 [group 1] and 35 treated after [group 2]). The χ2 test was used to examine the difference in parameters between groups. The PTV V100% PD ≥ 95% objective was met in 29.0% of group 1 vs 91.4% of group 2 (p < 0.01) plans. The PTV V90% PD ≥ 99% objective was met in 38.7% of group 1 vs 88.6% of group 2 (p < 0.01) plans. Overall, 4 plans in group 1 had CI > 1.2 vs none in group 2 (p = 0.04). For D2cm, 48.3% plans yielded a minor violation of the objectives and 16.1% a major violation for group 1, whereas 17.1% exhibited a minor violation and 2.9% a major violation for group 2 (p < 0.01). Spine SBRT plans can be improved on dose coverage, conformity, and dose falloff employing a combination of RTOG spine and lung SBRT protocol planning objectives

  10. Radiation dose-escalation trial for glioblastomas with 3D-conformal radiotherapy

    To investigate the effects of radiation dose-escalation on the treatment outcome, complications and the other prognostic variables for glioblastoma patients treated with 3D-conformal radiotherapy (3D-CRT). Between Jan 1997 and July 2002, a total of 75 patients with histologically proven diagnosis of glioblastoma were analyzed. The patients who had a Karnofsky Performance Score (KPS) of 60 or higher, and received at least 50 Gy of radiation to the tumor bed were eligible. All the patients were divided into two arms; Arm 1, the high-dose group was enrolled prospectively, and Arm 2, the low-dose group served as a retrospective control. Arm 1 patients received 63 ∼ 70 Gy (Median 66 Gy, fraction size 1.8 ∼ 2 Gy) with 3D-conformal radiotherapy, and Arm 2 received 59.4 Gy or less (Median 59.4 Gy, fraction size 1.8 Gy) with 2D-conventional radiotherapy. The Gross Tumor Volume (GTV) was defined by the surgical margin and the residual gross tumor on a contrast enhanced MRI. Surrounding edema was not included in the Clinical Target Volume (CTV) in Arm 1, so as to reduce the risk of late radiation associated complications; whereas as in Arm 2 it was included. The overall survival and progression free survival times were calculated from the data of surgery using the Kaplan-Meier method. The time to progression was measured with serial neurologic examinations and MRI or CT scans after RT completion. Acute and late toxicities were evaluated using the Radiation Therapy Oncology Group neurotoxicity scores. During the relatively short follow up period of 14 months, the median overall survival and progression free survival times were 15 ± 1.65 and 11 ± 0.95 months, respectively. There was a significantly longer survival time for the Arm 1 patients compared to those in Arm 2 (ρ = 0.028). For Arm 1 patients, the median survival and progression free survival times were 21 ± 5.03 and 12 ± 1.59 months, respectively, while for Arm 2 patients they were 14 ± 0.94 and 10 ± 1

  11. Factors influencing incidence of acute grade 2 morbidity in conformal and standard radiation treatment of prostate cancer

    Purpose: The fundament hypothesis of conformal radiation therapy is that tumor control can be increased by using conformal treatment techniques that allow a higher tumor dose while maintaining an acceptable level of complications. To test this hypothesis, it is necessary first to estimate the incidence of morbidity for both standard and conformal fields. In this study, we examine factors that influence the incidence of acute grade 2 morbidity in patients treated with conformal and standard radiation treatment for prostate cancer. Methods and Materials: Two hundred and forty-seven consecutive patients treated with conformal technique are combined with and compared to 162 consecutive patients treated with standard techniques. The conformal technique includes special immobilization by a cast, careful identification of the target volume in three dimensions, localization of the inferior border of the prostate using the retrograde urethrogram, and individually shaped portals that conform to the Planning Target Volume (PTV). Univariate analysis compares differences in the incidence of RTOG-EORTC grade two acute morbidity by technique, T stage, age, irradiated volume, and dose. Multivariate logistic regression includes these same variables. Results: In nearly all categories, the conformal treatment group experienced significantly fewer acute grade 2 complications than the standard treatment group. Only volume (prostate ± whole pelvis) and technique (conformal vs. standard) were significantly related to incidence of morbidity on multivariate analysis. When dose is treated as a continuous variable (rather than being dichotomized into two levels), a trend is observed on multivariate analysis, but it does not reach significant levels. The incidence of acute grade 2 morbidity in patients 65 years or older is significantly reduced by use of the conformal technique. Conclusion: The conformal technique is associated with fewer grade 2 acute toxicities for all patients. This

  12. Visual Outcomes in Pediatric Optic Pathway Glioma After Conformal Radiation Therapy

    Purpose: To assess visual outcome prospectively after conformal radiation therapy (CRT) in children with optic pathway glioma. Methods and Materials: We used CRT to treat optic pathway glioma in 20 children (median age 9.3 years) between July 1997 and January 2002. We assessed changes in visual acuity using the logarithm of the minimal angle of resolution after CRT (54 Gy) with a median follow-up of 24 months. We included in the study children who underwent chemotherapy (8 patients) or resection (9 patients) before CRT. Results: Surgery played a major role in determining baseline (pre-CRT) visual acuity (better eye: P=.0431; worse eye: P=.0032). The visual acuity in the worse eye was diminished at baseline (borderline significant) with administration of chemotherapy before CRT (P=.0726) and progression of disease prior to receiving CRT (P=.0220). In the worse eye, improvement in visual acuity was observed in patients who did not receive chemotherapy before CRT (P=.0289). Conclusions: Children with optic pathway glioma initially treated with chemotherapy prior to receiving radiation therapy have decreased visual acuity compared with those who receive primary radiation therapy. Limited surgery before radiation therapy may have a role in preserving visual acuity.

  13. Ultrahigh Resolution 3-Dimensional Imaging Project

    National Aeronautics and Space Administration — Southwest Sciences proposes to develop innovative instrumentation for the rapid, 3-dimensional imaging of biological tissues with cellular resolution. Our approach...

  14. The possible role of chromatin conformation changes in adaptive responses to ionizing radiation

    Organisms are affected by different DNA damaging agents naturally present in the environment or released as a result of human activity. Many defense mechanisms have evolved in organisms to minimize genotoxic damage. One of them is induced radioresistance or adaptive response. The adaptive response could be considered as a nonspecific phenomenon in which exposure to minimal stress could result in increased resistance to higher levels of the same or to other types of stress some hours later. A better understanding of the molecular mechanism underlying the adaptive response may lead to an improvement of cancer treatment, risk assessment and risk management strategies, radiation protection. The aim of current study was to study the possible role of chromatin conformation changes induced by ionizing radiation on the adaptive responses in human lymphocyte. For this aim the chromatin conformation have been studied in human lymphocytes from three non-smoking and three smoking healthy volunteers prior, and after espouser to gamma radiation (adaptive dose 0.1 Gy, challenge dose 1.5 Gy and adaptive + dose challenge). Chromosomal aberrations and micronucleus have been used as end point to study radio cytotoxicity and adaptive response. Our results indicated individual differences in radio adaptive response and the level of this response was dependent of chromatin de condensation induced by a adaptive small dose.The results showed that different dose of gamma rays induce a chromatin de condensation in human lymphocyte. The maximum chromatin relaxation were record when lymphocyte exposed to adaptive dose (0.1 Gy.). Results also showed that Adaptive dose have affected on the induction of challenge dose (1.5 Gy) of chromosome aberration and micronucleus . The comparison of results of chromatin de condensation induction as measured by flow cytometry and cytogenetic damages measured by chromosomal aberrations or micronucleus, was showed a proportionality of adaptive response with

  15. Teleportation of a 3-dimensional GHZ State

    Cao, Hai-Jing; Wang, Huai-Sheng; Li, Peng-Fei; Song, He-Shan

    2012-05-01

    The process of teleportation of a completely unknown 3-dimensional GHZ state is considered. Three maximally entangled 3-dimensional Bell states function as quantum channel in the scheme. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional GHZ state.

  16. 3-dimensional Griess algebras and Miyamoto involutions

    lam, Ching Hung; Yamauchi, Hiroshi

    2016-01-01

    We consider a series of VOAs generated by 3-dimensional Griess algebras. We will show that these VOAs can be characterized by their 3-dimensional Griess algebras and their structures are uniquely determined. As an application, we will determine the groups generated by the Miyamoto involutions associated to Virasoro vectors of our VOAs.

  17. Dosimetric comparison of three dimensional conformal radiation therapy versus intensity modulated radiation therapy in accelerated partial breast irradiation

    S Moorthy

    2016-01-01

    Full Text Available Aim of Study: Breast conserving surgery (BCS is the standard treatment for stage I and II breast cancer. Multiple studies have shown that recurrences after lumpectomy occur mainly in or near the tumor bed. Use of accelerated partial breast irradiation (APBI allows for significant reduction in the overall treatment time that results in increasing patient compliance and decreasing healthcare costs. We conducted a treatment planning study to evaluate the role of intensity modulated radiation therapy (IMRT with regards to three-dimensional conformal radiation therapy (3DCRT in APBI. Materials and Methods: Computed tomography planning data sets of 33 patients (20 right sided and 13 left sided with tumor size less than 3 cm and negative axillary lymph nodes were used for our study. Tumor location was upper outer, upper inner, central, lower inner, and lower outer quadrants in 10, 10, 5, 4 and 4 patients, respectively. Multiple 3DCRT and IMRT plans were created for each patient. Total dose of 38.5 Gy in 10 fractions were planned. Dosimetric analysis was done for the best 3DCRT and IMRT plans. Results: The target coverage has been achieved by both the methods but IMRT provided better coverage (P = 0.04 with improved conformity index (P = 0.01. Maximum doses were well controlled in IMRT to below 108% (P < 0.01. Heart V2 Gy (P < 0.01, lung V5 Gy (P = 0.01, lung V10 Gy (P = 0.02, contralateral breast V1 Gy (P < 0.01, contralateral lung V2 Gy (P < 0.01, and ipsilateral uninvolved breast (P < 0.01 doses were higher with 3DCRT compared to IMRT. Conclusion: Dosimetrically, IMRT–APBI provided best target coverage with less dose to normal tissues compared with 3DCRT-APBI.

  18. Disease Control After Reduced Volume Conformal and Intensity Modulated Radiation Therapy for Childhood Craniopharyngioma

    Merchant, Thomas E., E-mail: thomas.merchant@stjude.org [St Jude Children' s Research Hospital, Radiological Sciences, Memphis, Tennessee (United States); Kun, Larry E.; Hua, Chia-Ho [St Jude Children' s Research Hospital, Radiological Sciences, Memphis, Tennessee (United States); Wu, Shengjie; Xiong, Xiaoping [St Jude Children' s Research Hospital, Biostatistics, Memphis, Tennessee (United States); Sanford, Robert A.; Boop, Frederick A. [Semmes Murphey Neurologic and Spine Institute, Neurosurgery, Memphis, Tennessee (United States)

    2013-03-15

    Purpose: To estimate the rate of disease control after conformal radiation therapy using reduced clinical target volume (CTV) margins and to determine factors that predict for tumor progression. Methods and Materials: Eighty-eight children (median age, 8.5 years; range, 3.2-17.6 years) received conformal or intensity modulated radiation therapy between 1998 and 2009. The study group included those prospectively treated from 1998 to 2003, using a 10-mm CTV, defined as the margin surrounding the solid and cystic tumor targeted to receive the prescription dose of 54 Gy. The CTV margin was subsequently reduced after 2003, yielding 2 groups of patients: those treated with a CTV margin greater than 5 mm (n=26) and those treated with a CTV margin less than or equal to 5 mm (n=62). Disease progression was estimated on the basis of additional variables including sex, race, extent of resection, tumor interventions, target volume margins, and frequency of weekly surveillance magnetic resonance (MR) imaging during radiation therapy. Median follow-up was 5 years. Results: There was no difference between progression-free survival rates based on CTV margins (>5 mm vs ≤5 mm) at 5 years (88.1% ± 6.3% vs 96.2% ± 4.4% [P=.6386]). There were no differences based on planning target volume (PTV) margins (or combined CTV plus PTV margins). The PTV was systematically reduced from 5 to 3 mm during the time period of the study. Factors predictive of superior progression-free survival included Caucasian race (P=.0175), no requirement for cerebrospinal fluid shunting (P=.0066), and number of surveillance imaging studies during treatment (P=.0216). Patients whose treatment protocol included a higher number of weekly surveillance MR imaging evaluations had a lower rate of tumor progression. Conclusions: These results suggest that targeted volume reductions for radiation therapy using smaller margins are feasible and safe but require careful monitoring. We are currently investigating

  19. THREE-DIMENSIONAL CONFORMAL RADIATION THERAPY FOR LOCALLY RECURRENT NASOPHARYNGEAL CARCINOMA

    2001-01-01

    Objective: To investigate the safety and effectiveness of three-dimensional conformal radiation therapy (3-D CRT) for locally recurrent nasopharyngeal carcinoma (NPC). Methods: From April 1998 to March 2000, 34 patients who had undergone previous external beam radiation therapy were retreated with 3-D CRT for locally recurrent NPC (33 poorly differentiated squamous cell carcinomas, 1 adenoma). The patients were re-staged according to Huaqing staging system with the following distribution: T1N0M0 in 5 cases, T2N0M0 in 11 cases, T3N0M0 in 12 cases, T4N0M0 in 6 cases. The maximal dimension of the gross tumor volume (GTV) ranged from 1.0 cm to 5.0 cm (median: 2.9 cm). CT simulation and 3-D planning were used to ensure full and conformal coverage of the planning target volume (PTV) by treated volume, while minimizing the absorbed dose of the adjacent normal tissue. 5-7 static conformal coplanar or noncoplanar portals were delivered for each fraction irradiation. The total dose delivered ranged from 65-70 Gy, with 2.5 Gy per fractionation, one fractionation per day, 5 days a week. Median follow-up time from 3-D CRT was 25 months (range: 12-36 months). Results: Over the follow-up period, local recurrence was observed in 3 patients, regional failure in 3, distant metastasis in 3, and six patients died; 88.2% (30/34) of the patient maintained local control, 82.4% (28/34) survived, and 76.5% (26/34) survived with no evidence of tumor. Acute complications were minor and few. The overall incidence of late complication was 20.6% (7/34), and severe complication was 14.7% (5/34), after re-irradiation with 3-D CRT. Conclusion: 3-D CRT is safety and effectiveness for most of the patients with locally recurrent NPC. Our preliminary results indicate a high local control rate and a low complication rate. The long-term curative effect and sequelae await further study.

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

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

    2015-10-01

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

  1. Emotional and Behavioral Functioning After Conformal Radiation Therapy for Pediatric Ependymoma

    Willard, Victoria W.; Conklin, Heather M. [Department of Psychology, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Boop, Frederick A. [Department of Surgery, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Department of Neurosurgery, Semmes-Murphey Neurologic and Spine Institute, Memphis, Tennessee (United States); Wu, Shengjie [Department of Biostatistics, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Merchant, Thomas E., E-mail: thomas.merchant@stjude.org [Division of Radiation Oncology, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2014-03-15

    Purpose: The standard of care for pediatric patients with ependymoma involves postoperative radiation therapy. Prior research suggests that conformal radiation therapy (CRT) is associated with relative sparing of cognitive and academic functioning, but little is known about the effect of CRT on emotional and behavioral functioning. Methods and Materials: A total of 113 patients with pediatric ependymoma underwent CRT using photons as part of their enrollment on an institutional trial. Patients completed annual evaluations of neurocognitive functioning during the first 5 years after CRT. Emotional and behavioral functioning was assessed via the Child Behavior Checklist. Results: Before CRT, emotional and behavioral functioning were commensurate with those of the normative population and within normal limits. After 5 years, means remained within normal limits but were significantly below the normative mean. Linear mixed models revealed a significant increase in attention problems over time. These problems were associated with age at diagnosis/CRT, tumor location, and extent of resection. A higher-than-expected incidence of school problems was present at all assessment points after baseline. Conclusions: The use of photon CRT for ependymoma is associated with relatively stable emotional and behavioral functioning during the first 5 years after treatment. The exception is an increase in attention problems. Results suggest that intervening earlier in the survivorship period—during the first year posttreatment—may be beneficial.

  2. Emotional and Behavioral Functioning After Conformal Radiation Therapy for Pediatric Ependymoma

    Purpose: The standard of care for pediatric patients with ependymoma involves postoperative radiation therapy. Prior research suggests that conformal radiation therapy (CRT) is associated with relative sparing of cognitive and academic functioning, but little is known about the effect of CRT on emotional and behavioral functioning. Methods and Materials: A total of 113 patients with pediatric ependymoma underwent CRT using photons as part of their enrollment on an institutional trial. Patients completed annual evaluations of neurocognitive functioning during the first 5 years after CRT. Emotional and behavioral functioning was assessed via the Child Behavior Checklist. Results: Before CRT, emotional and behavioral functioning were commensurate with those of the normative population and within normal limits. After 5 years, means remained within normal limits but were significantly below the normative mean. Linear mixed models revealed a significant increase in attention problems over time. These problems were associated with age at diagnosis/CRT, tumor location, and extent of resection. A higher-than-expected incidence of school problems was present at all assessment points after baseline. Conclusions: The use of photon CRT for ependymoma is associated with relatively stable emotional and behavioral functioning during the first 5 years after treatment. The exception is an increase in attention problems. Results suggest that intervening earlier in the survivorship period—during the first year posttreatment—may be beneficial

  3. Dosimetry in brain tumor phantom at 15 MV 3D conformal radiation therapy

    Glioblastoma multiforme (GBM) is the most common, aggressive, highly malignant and infiltrative of all brain tumors with low rate of control. The main goal of this work was to evaluate the spatial dose distribution into a GBM simulator inside a head phantom exposed to a 15 MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Such phantom holds the following synthetic structures: brain and spinal cord, skull, cervical and thoracic vertebrae, jaw, hyoid bone, laryngeal cartilages, head and neck muscles and skin. Computer tomography (CT) of the simulator was taken, capturing a set of contrasted references. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples at coronal, sagittal-anterior and sagittal-posterior positions, inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, measured at coronal section, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. And, as final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols

  4. Target volume definition for three-dimensional conformal radiation therapy of lung cancer.

    Armstrong, J G

    1998-06-01

    Three-dimensional conformal radiation therapy (3DCRT) is a mode of high precision radiotherapy which has the potential to improve the therapeutic ratio of radiation therapy for locally advanced non-small cell lung cancer. The preliminary clinical experience with 3DCRT has been promising and justifies further endeavour to refine its clinical application and ultimately test its role in randomized trials. There are several steps to be taken before 3DCRT evolves into an effective single modality for the treatment of lung cancer and before it is effectively integrated with chemotherapy. This article addresses core issues in the process of target volume definition for the application of 3DCRT technology to lung cancer. The International Commission on Radiation Units and Measurements Report no. 50 definitions of target volumes are used to identify the factors influencing target volumes in lung cancer. The rationale for applying 3DCRT to lung cancer is based on the frequency of failure to eradicate gross tumour with conventional approaches. It may therefore be appropriate to ignore subclinical or microscopic extensions when designing a clinical target volume, thereby restricting target volume size and allowing dose escalation. When the clinical target volume is expanded to a planning target volume, an optimized margin would result in homogeneous irradiation to the highest dose feasible within normal tissue constraints. To arrive at such optimized margins, multiple factors, including data acquisition, data transfer, patient movement, treatment reproducibility, and internal organ and target volume motion, must be considered. These factors may vary significantly depending on technology and techniques, and published quantitative analyses are no substitute for meticulous attention to detail and audit of performance. PMID:9849380

  5. A comparative analysis of 3D conformal deep inspiratory–breath hold and free-breathing intensity-modulated radiation therapy for left-sided breast cancer

    Patients undergoing radiation for left-sided breast cancer have increased rates of coronary artery disease. Free-breathing intensity-modulated radiation therapy (FB-IMRT) and 3-dimensional conformal deep inspiratory–breath hold (3D-DIBH) reduce cardiac irradiation. The purpose of this study is to compare the dose to organs at risk in FB-IMRT vs 3D-DIBH for patients with left-sided breast cancer. Ten patients with left-sided breast cancer had 2 computed tomography scans: free breathing and voluntary DIBH. Optimization of the IMRT plan was performed on the free-breathing scan using 6 noncoplanar tangential beams. The 3D-DIBH plan was optimized on the DIBH scan and used standard tangents. Mean volumes of the heart, the left anterior descending coronary artery (LAD), the total lung, and the right breast receiving 5% to 95% (5% increments) of the prescription dose were calculated. Mean volumes of the heart and the LAD were lower (p<0.05) in 3D-DIBH for volumes receiving 5% to 80% of the prescription dose for the heart and 5% for the LAD. Mean dose to the LAD and heart were lower in 3D-DIBH (p≤0.01). Mean volumes of the total lung were lower in FB-IMRT for dose levels 20% to 75% (p<0.05), but mean dose was not different. Mean volumes of the right breast were not different for any dose; however, mean dose was lower for 3D-DIBH (p = 0.04). 3D-DIBH is an alternative approach to FB-IMRT that provides a clinically equivalent treatment for patients with left-sided breast cancer while sparing organs at risk with increased ease of implementation

  6. Target volume delineation and field setup. A practical guide for conformal and intensity-modulated radiation therapy

    Lee, Nancy Y. [Memorial Sloan-Kettering Cancer Center, New York, NY (United States). Radiation Oncology; Lu, Jiade J. (eds.) [National Univ. Health System, Singapore (Singapore). Dept. of Radiation Oncology; National Univ. of Singapore (Singapore). Dept. of Medicine

    2013-03-01

    Practical handbook on selection and delineation of tumor volumes and fields for conformal radiation therapy, including IMRT. Helpful format facilitating use on a step-by-step basis in daily practice. Designed to ensure accurate coverage of commonly encountered tumors along their routes of spread. This handbook is designed to enable radiation oncologists to appropriately and confidently delineate tumor volumes/fields for conformal radiation therapy, including intensity-modulated radiation therapy (IMRT), in patients with commonly encountered cancers. The orientation of this handbook is entirely practical, in that the focus is on the illustration of clinical target volume (CTV) delineation for each major malignancy. Each chapter provides guidelines and concise knowledge on CTV selection for a particular disease, explains how the anatomy of lymphatic drainage shapes the selection of the target volume, and presents detailed illustrations of volumes, slice by slice, on planning CT images. While the emphasis is on target volume delineation for three-dimensional conformal therapy and IMRT, information is also provided on conventional radiation therapy field setup and planning for certain malignancies for which IMRT is not currently suitable.

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

    Stefano G. Masciullo

    2012-11-01

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

  8. Learning and Memory Following Conformal Radiation Therapy for Pediatric Craniopharyngioma and Low-Grade Glioma

    Purpose: The primary objective of this study was to examine whether children with low-grade glioma (LGG) or craniopharyngioma had impaired learning and memory after conformal radiation therapy (CRT). A secondary objective was to determine whether children who received chemotherapy before CRT, a treatment often used to delay radiation therapy in younger children with LGG, received any protective benefit with respect to learning. Methods and Materials: Learning and memory in 57 children with LGG and 44 children with craniopharyngioma were assessed with the California Verbal Learning Test–Children's Version and the Visual-Auditory Learning tests. Learning measures were administered before CRT, 6 months later, and then yearly for a total of 5 years. Results: No decline in learning scores after CRT was observed when patients were grouped by diagnosis. For children with LGG, chemotherapy before CRT did not provide a protective effect on learning. Multiple regression analyses, which accounted for age and tumor volume and location, found that children treated with chemotherapy before CRT were at greater risk of decline on learning measures than those treated with CRT alone. Variables predictive of learning and memory decline included hydrocephalus, shunt insertion, younger age at time of treatment, female gender, and pre-CRT chemotherapy. Conclusions: This study did not reveal any impairment or decline in learning after CRT in overall aggregate learning scores. However, several important variables were found to have a significant effect on neurocognitive outcome. Specifically, chemotherapy before CRT was predictive of worse outcome on verbal learning in LGG patients. In addition, hydrocephalus and shunt insertion in craniopharyngioma were found to be predictive of worse neurocognitive outcome, suggesting a more aggressive natural history for those patients.

  9. Learning and Memory Following Conformal Radiation Therapy for Pediatric Craniopharyngioma and Low-Grade Glioma

    Di Pinto, Marcos [Department of Pediatric Psychology, Children' s Hospital of Orange County, Orange, California (United States); Conklin, Heather M. [Department of Psychology, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Li, Chenghong [Department of Biostatistics, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Merchant, Thomas E., E-mail: thomas.merchant@stjude.org [Division of Radiation Oncology, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2012-11-01

    Purpose: The primary objective of this study was to examine whether children with low-grade glioma (LGG) or craniopharyngioma had impaired learning and memory after conformal radiation therapy (CRT). A secondary objective was to determine whether children who received chemotherapy before CRT, a treatment often used to delay radiation therapy in younger children with LGG, received any protective benefit with respect to learning. Methods and Materials: Learning and memory in 57 children with LGG and 44 children with craniopharyngioma were assessed with the California Verbal Learning Test-Children's Version and the Visual-Auditory Learning tests. Learning measures were administered before CRT, 6 months later, and then yearly for a total of 5 years. Results: No decline in learning scores after CRT was observed when patients were grouped by diagnosis. For children with LGG, chemotherapy before CRT did not provide a protective effect on learning. Multiple regression analyses, which accounted for age and tumor volume and location, found that children treated with chemotherapy before CRT were at greater risk of decline on learning measures than those treated with CRT alone. Variables predictive of learning and memory decline included hydrocephalus, shunt insertion, younger age at time of treatment, female gender, and pre-CRT chemotherapy. Conclusions: This study did not reveal any impairment or decline in learning after CRT in overall aggregate learning scores. However, several important variables were found to have a significant effect on neurocognitive outcome. Specifically, chemotherapy before CRT was predictive of worse outcome on verbal learning in LGG patients. In addition, hydrocephalus and shunt insertion in craniopharyngioma were found to be predictive of worse neurocognitive outcome, suggesting a more aggressive natural history for those patients.

  10. Conformal radiation therapy for portal vein tumor thrombosis of hepatocellular carcinoma

    Background and purpose: The prognosis of patients with portal vein tumor thrombosis (PVTT) from hepatocellular carcinoma (HCC) is poor; without treatment, their survival is less than 3 months. We retrospectively evaluated the treatment outcomes of conformal radiation therapy (CRT) in patients with HCC-PVTT. Materials and methods: Thirty-eight HCC patients with PVTT in whom other treatment modalities were not indicated underwent CRT. The total dose was translated into a biologic effective dose (BED) of 23.4-59.5 Gy10 (median 50.7 Gy10) as the α/β ratio = 10. Predictive factors including the age, performance status, Child-Pugh classification, PVTT size, and BED were evaluated for tumor response and survival. Results: Complete response (CR), partial response (PR), stable disease (SD), and progressive disease (PD) were observed in 6 (15.8%), 11 (28.9%), 17 (44.7%), and 4 (10.5%) patients, respectively. The response rate (CR + PR) was 44.7%. The PVTT size (10) were significant factors for tumor response. The median survival and 1-year survival rate were 9.6 months and 39.4%. The Child-Pugh classification (A vs. B) and BED were significant factors for survival. Conclusions: CRT is effective not only for tumor response but also for survival in HCC-PVTT patients in whom other treatment modalities are not indicated

  11. Investigating Verbal and Visual Auditory Learning After Conformal Radiation Therapy for Childhood Ependymoma

    Purpose: The primary objective of this study was to determine whether children with localized ependymoma experience a decline in verbal or visual-auditory learning after conformal radiation therapy (CRT). The secondary objective was to investigate the impact of age and select clinical factors on learning before and after treatment. Methods and Materials: Learning in a sample of 71 patients with localized ependymoma was assessed with the California Verbal Learning Test (CVLT-C) and the Visual-Auditory Learning Test (VAL). Learning measures were administered before CRT, at 6 months, and then yearly for a total of 5 years. Results: There was no significant decline on measures of verbal or visual-auditory learning after CRT; however, younger age, more surgeries, and cerebrospinal fluid shunting did predict lower scores at baseline. There were significant longitudinal effects (improved learning scores after treatment) among older children on the CVLT-C and children that did not receive pre-CRT chemotherapy on the VAL. Conclusion: There was no evidence of global decline in learning after CRT in children with localized ependymoma. Several important implications from the findings include the following: (1) identification of and differentiation among variables with transient vs. long-term effects on learning, (2) demonstration that children treated with chemotherapy before CRT had greater risk of adverse visual-auditory learning performance, and (3) establishment of baseline and serial assessment as critical in ascertaining necessary sensitivity and specificity for the detection of modest effects.

  12. Synchrotron Radiation Circular Dichroism (SRCD) Spectroscopy - An Enhanced Method for Examining Protein Conformations and Protein Interactions

    B Wallace; R Janes

    2011-12-31

    CD (circular dichroism) spectroscopy is a well-established technique in structural biology. SRCD (synchrotron radiation circular dichroism) spectroscopy extends the utility and applications of conventional CD spectroscopy (using laboratory-based instruments) because the high flux of a synchrotron enables collection of data at lower wavelengths (resulting in higher information content), detection of spectra with higher signal-to-noise levels and measurements in the presence of absorbing components (buffers, salts, lipids and detergents). SRCD spectroscopy can provide important static and dynamic structural information on proteins in solution, including secondary structures of intact proteins and their domains, protein stability, the differences between wild-type and mutant proteins, the identification of natively disordered regions in proteins, and the dynamic processes of protein folding and membrane insertion and the kinetics of enzyme reactions. It has also been used to effectively study protein interactions, including protein-protein complex formation involving either induced-fit or rigid-body mechanisms, and protein-lipid complexes. A new web-based bioinformatics resource, the Protein Circular Dichroism Data Bank (PCDDB), has been created which enables archiving, access and analyses of CD and SRCD spectra and supporting metadata, now making this information publicly available. To summarize, the developing method of SRCD spectroscopy has the potential for playing an important role in new types of studies of protein conformations and their complexes.

  13. The 3-dimensional Einstein-Klein-Gordon system in characteristic numerical relativity

    Barreto, W.; Da Silva, A.; Gomez, R.; Lehner, L.; Rosales, L.; Winicour, J.

    2005-01-01

    We incorporate a massless scalar field into a 3-dimensional code for the characteristic evolution of the gravitational field. The extended 3-dimensional code for the Einstein--Klein--Gordon system is calibrated to be second order convergent. It provides an accurate calculation of the gravitational and scalar radiation at infinity. As an application, we simulate the fully nonlinear evolution of an asymmetric scalar pulse of ingoing radiation propagating toward an interior Schwarzschild black h...

  14. 3D Conformal Radiation Therapy: Multimedia Introduction to Methods and Techniques

    W Schlegel and A Mahr Berlin: Springer (2001) 107 Euros, ISBN: 3-540-14884-1. This book on CD-ROM, written by Wolfgang Schlegel and Andreas Mahr of the Radiation Physics Department of the Deutsches Krebsforschungzentrum (DKFZ) in Heidelberg, is extensive and comprehensive. It covers almost all issues of 3D conformal therapy, including the most recent developments. It is very useful as an introduction for physicists new to the field of radiation therapy and it also has its value as a reference guide for experienced medical physicists. It is particularly useful as a source of illustrations for those teaching in radiation therapy. In general the book is well written and the material is well organized. The contents of the different chapters are not very well balanced, however. Some subjects are discussed quite extensively, while others are treated very briefly. The authors explain in the introduction that the emphasis will be on the work performed at the DKFZ and that comprehensiveness was not a primary concern. Nevertheless some paragraphs could be more extensive, whereas in some paragraphs less detail would be preferable. In most cases the figures and movies illustrate the subject well and the movies in particular are often very instructive. Some of the movies, however, do not really contribute to the understanding of the subject and could be omitted. On the other hand in some paragraphs there is a lack of illustrations. The presentation on CD-ROM has great advantages as compared to a conventional book. One can navigate around easily, connections between chapters and paragraphs are easily made (via links) and one can jump directly to the reference list and back. The option of interactive illustrations and movies is a unique and nice feature. A 'find' option would be a very helpful extra to locate information. Part I on CRT with photon and electron beams starts with a chapter on immobilization with emphasis on stereotactic treatments, followed by a chapter on imaging

  15. A study of the radiobiological modeling of the conformal radiation therapy in cancer treatment

    Pyakuryal, Anil Prasad

    Cancer is one of the leading causes of mortalities in the world. The precise diagnosis of the disease helps the patients to select the appropriate modality of the treatments such as surgery, chemotherapy and radiation therapy. The physics of X-radiation and the advanced imaging technologies such as positron emission tomography (PET) and computed tomography (CT) plays an important role in the efficient diagnosis and therapeutic treatments in cancer. However, the accuracy of the measurements of the metabolic target volumes (MTVs) in the PET/CT dual-imaging modality is always limited. Similarly the external beam radiation therapy (XRT) such as 3D conformal radiotherapy (3DCRT) and intensity modulated radiation therapy (IMRT) is the most common modality in the radiotherapy treatment. These treatments are simulated and evaluated using the XRT plans and the standard methodologies in the commercial planning system. However, the normal organs are always susceptible to the radiation toxicity in these treatments due to lack of knowledge of the appropriate radiobiological models to estimate the clinical outcomes. We explored several methodologies to estimate MTVs by reviewing various techniques of the target volume delineation using the static phantoms in the PET scans. The review suggests that the more precise and practical method of delineating PET MTV should be an intermediate volume between the volume coverage for the standardized uptake value (SUV; 2.5) of glucose and the 50% (40%) threshold of the maximum SUV for the smaller (larger) volume delineations in the radiotherapy applications. Similarly various types of optimal XRT plans were designed using the CT and PET/CT scans for the treatment of various types of cancer patients. The qualities of these plans were assessed using the universal plan-indices. The dose-volume criteria were also examined in the targets and organs by analyzing the conventional dose-volume histograms (DVHs). The biological models such as tumor

  16. Dose escalation with three-dimensional conformal radiation therapy affects the outcome in prostate cancer

    Purpose: Three-dimensional conformal radiation therapy (3D-CRT) is a technique designed to deliver prescribed radiation doses to localized tumors with high precision, while effectively excluding the surrounding normal tissues. It facilitates tumor dose escalation which should overcome the relative resistance of tumor clonogens to conventional radiation dose levels. The present study was undertaken to test this hypothesis in patients with clinically localized prostate cancer. Methods and Materials: A total of 743 patients with clinically localized prostate cancer were treated with 3D-CRT. As part of a phase I study, the tumor target dose was increased from 64.8 to 81 Gy in increments of 5.4 Gy. Tumor response was evaluated by post-treatment decrease of serum prostate-specific antigen (PSA) to levels of ≤1.0 ng/ml and by sextant prostate biopsies performed ≥2.5 years after completion of 3D-CRT. PSA relapse-free survival was used to evaluate long-term outcome. The median follow-up was 3 years (range: 1-7.6 years). Results: Induction of an initial clinical response was dose-dependent, with 90% of patients receiving 75.6 or 81.0 Gy achieving a PSA nadir ≤1.0 ng compared with 76% and 56% for those treated with 70.2 Gy and 64.8 Gy, respectively (p < 0.001). The 5-year actuarial PSA relapse-free survival for patients with favorable prognostic indicators (stage T1-2, pretreatment PSA ≤10.0 ng/ml and Gleason score ≤6) was 85%, compared to 65% for those with intermediate prognosis (one of the prognostic indicators with a higher value) and 35% for the group with unfavorable prognosis (two or more indicators with higher values) (p < 0.001). PSA relapse-free survival was significantly improved in patients with intermediate and unfavorable prognosis receiving ≥75.6 Gy (p < 0.05). A positive biopsy at ≥2.5 years after 3D-CRT was observed in only 1/15 (7%) of patients receiving 81.0 Gy, compared with 12/25 (48%) after 75.6 Gy, 19/42 (45%) after 70.2 Gy, and 13/23 (57

  17. Conformal Infinity

    Frauendiener Jörg

    2004-01-01

    Full Text Available The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, 'conformal infinity' is related to almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved from physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation, and how it lends itself very naturally to the solution of radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

  18. Conformal Infinity

    Frauendiener Jörg

    2000-08-01

    Full Text Available The notion of conformal infinity has a long history within the research in Einstein's theory of gravity. Today, ``conformal infinity'' is related with almost all other branches of research in general relativity, from quantisation procedures to abstract mathematical issues to numerical applications. This review article attempts to show how this concept gradually and inevitably evolved out of physical issues, namely the need to understand gravitational radiation and isolated systems within the theory of gravitation and how it lends itself very naturally to solve radiation problems in numerical relativity. The fundamental concept of null-infinity is introduced. Friedrich's regular conformal field equations are presented and various initial value problems for them are discussed. Finally, it is shown that the conformal field equations provide a very powerful method within numerical relativity to study global problems such as gravitational wave propagation and detection.

  19. Variation of clinical target volume definition in three-dimensional conformal radiation therapy for prostate cancer

    Purpose: Currently, three-dimensional conformal radiation therapy (3D-CRT) planning relies on the interpretation of computed tomography (CT) axial images for defining the clinical target volume (CTV). This study investigates the variation among multiple observers to define the CTV used in 3D-CRT for prostate cancer. Methods and Materials: Seven observers independently delineated the CTVs (prostate ± seminal vesicles [SV]) from the CT simulation data of 10 prostate cancer patients undergoing 3D-CRT. Six patients underwent CT simulation without the use of contrast material and serve as a control group. The other 4 had urethral and bladder opacification with contrast medium. To determine interobserver variation, we evaluated the derived volume, the maximum dimensions, and the isocenter for each examination of CTV. We assessed the reliability in the CTVs among the observers by correlating the variation for each class of measurements. This was estimated by intraclass correlation coefficient (ICC), with 1.00 defining absolute correlation. Results: For the prostate volumes, the ICC was 0.80 (95% confidence interval [CI]: 0.56-0.96). This changed to 0.92 (95% CI: 0.75-0.99) with the use of contrast material. Similarly, the maximal prostatic dimensions were reliable and improved. There was poor agreement in defining the SV. For this structure, the ICC never exceeded 0.28. The reliability of the isocenter was excellent, with the ICC exceeding 0.83 and 0.90 for the prostate ± SV, respectively. Conclusions: In 3D-CRT for prostate cancer, there was excellent agreement among multiple observers to define the prostate target volume but poor agreement to define the SV. The use of urethral and bladder contrast improved the reliability of localizing the prostate. For all CTVs, the isocenter was very reliable and should be used to compare the variation in 3D dosimetry among multiple observers

  20. Longitudinal analysis of quality of life in patients receiving conformal radiation therapy for prostate cancer

    Geinitz, Hans; Thamm, Reinhard; Scholz, Christian; Heinrich, Christine; Prause, Nina; Kerndl, Simone; Molls, Michael; Zimmermann, Frank B. [Dept. of Radiotherapy and Radiooncology, Technische Univ. Muenchen (Germany); Keller, Monika [Psychooncology Section, Dept. of Psychosomatic and General Clinical Medicine, Univ. Hospital, Heidelberg (Germany); Busch, Raymonde [Inst. of Medical Statistics and Epidemiology, Technische Univ. Muenchen (Germany)

    2010-01-15

    Purpose: To prospectively assess quality of life (QoL) in patients receiving conformal radiation therapy (CRT) for prostate cancer. Patients and Methods: 78 men with definitive CRT for prostate cancer were entered into the study. Patients were assessed before CRT, at 40 and 60 Gy, and 2, 12 and 24 months after the end of treatment. QoL was assessed using the EORTC Quality of Life Questionnaire C30 and the prostate module PR25. Changes in mean QoL scores with time of {>=} 10 points were considered clinically relevant. Results: Global QoL did not change statistically significant during CRT and was slightly above baseline levels during follow-up. CRT had a statistically significant negative short-term impact on role functioning, fatigue, and PR25 urinary symptoms. The scores recovered within 2 months to 1 year after CRT. Emotional functioning and social functioning scores slightly increased during and after CRT. Role functioning decreased by > 10 points at 60 Gy and urinary symptoms decreased by > 10 points at 40 and 60 Gy. All other differences were < 10 points. A high number of concomitant diseases and having no children were negative pretreatment predictors for long-term global QoL. Conclusion: Definitive CRT for prostate cancer does not compromise global QoL during therapy and up to 2 years after treatment. It has a limited negative effect on role functioning, urinary symptoms and, to a lesser extent, on fatigue with restitution within 2 months to 1 year after treatment. (orig.)

  1. Three-dimensional conformal radiation combined with transarterial chemoembolization for unresectable primary liver cancer

    Objective: To evaluate the therapeutic efficacy of three dimensional conformal radiotherapy (3DCRT) plus transarterial chemoembolization(TACE) for unresectable primary liver cancer. Methods: Eighty-two patients with unresectable primary liver cancer were randomly divided into two groups: 41 were treated with 3DCRT plus TACE and the rest were treated with TACE alone. For TACE, 1000-1250 mg 5-fluorouracil and 20-30 mg hydroxycamptothecin were perfused into the hepatic arteries then 60-80 mg cisplatin and 14-20 mg mitomycin C (or 50-60 mg epirubicin) and iodized oil 10-30 ml were given to embolized the hepatic arteries which was then followed by 1-2 mm gelfoam particles. TACE were treated with 1-3 sessions in either group. For 3DCRT, radiation was given by 6 MV X-ray. Patients whose planned target volume (PTV) was smaller than 216 cm3 received a total dose of 40-56 Gy, 5-8 Gy per session every other day. Patients whose PTV was larger than 216 cm3 received a total dose of 36-44 Gy, 4 Gy per session every other day. Results: The response rate (CR + PR) of 3DCRT plus TACE group and TACE alone group were 87.8% and 58.5%, with the difference statistically significant (χ2=8.94, P 2=5.52, P 2 = 5.49, P < 0. 05). The main factors affecting the prognosis in the 3DCRT plus TACE group were liver function and the size of tumor. Conclusion: Combined 3DCRT and TACE is more effective than TACE alone. It can effect a longer interval of control and higher survival in patients with unresectable primary hepatobiliary cancer

  2. Accelerated partial breast irradiation using 3D conformal radiation therapy (3D-CRT)

    Purpose: We present a novel three-dimensional conformal radiation therapy (3D-CRT) technique to treat the lumpectomy cavity, plus a 1.5-cm margin, in patients with early-stage breast cancer and study its clinical feasibility. Methods and Materials: A 3D-CRT technique for partial-breast irradiation was developed using archived CT scans from 7 patients who underwent an active breathing control study. The clinical feasibility of this technique was then assessed in 9 patients who were prospectively enrolled on an Investigational Review Board-approved protocol of partial-breast irradiation. The prescribed dose was 34 Gy in 5 patients and 38.5 Gy in 4 patients, delivered in 10 fractions twice daily over 5 consecutive days. The impact of both breathing motion and patient setup uncertainty on clinical target volume (CTV) coverage was studied, and an appropriate CTV-to-PTV (planning target volume) margin was calculated. Results: By adding a CTV-to-PTV 'breathing-only' margin of 5 mm, 98%-100% of the CTV remained covered by the 95% isodose surface at the extremes of normal inhalation and normal exhalation. The 'total' CTV-to-PTV margin employed to accommodate organ motion and setup error (10 mm) was found to be sufficient to accommodate the observed uncertainty in the delivery precision. Patient tolerance was excellent, and acute toxicity was minimal. No skin changes were noted during treatment, and at the initial 4-8-week follow-up visit, only mild localized hyperpigmentation and/or erythema was observed. No instances of symptomatic radiation pneumonitis have occurred. Conclusions: Accelerated partial-breast irradiation using 3D-CRT is technically feasible, and acute toxicity to date has been minimal. A CTV-to-PTV margin of 10 mm seems to provide coverage for most patients. However, more patients and additional studies will be needed to validate the accuracy of this margin, and longer follow-up will be needed to assess acute and chronic toxicity, tumor control, and cosmetic

  3. Properties of 3-dimensional line location models

    Brimberg, Jack; Juel, Henrik; Schöbel, Anita

    2002-01-01

    We consider the problem of locating a line with respect to some existing facilities in 3-dimensional space, such that the sum of weighted distances between the line and the facilities is minimized. Measuring distance using the l\\_p norm is discussed, along with the special cases of Euclidean and...

  4. Homological aperiodic tilings of 3-dimensional geometries

    Nowak, Piotr W

    2012-01-01

    We construct the first aperiodic tiles for two amenable 3-dimensional Lie groups: Sol and the Heisenberg group. Our construction relies on the use of higher-dimensional uniformly finite homology. In particular, we settle completely the existence of aperiodic tiles for all of the non-compact geometries of 3-manifolds appearing in the geometrization conjecture.

  5. Doses to Carotid Arteries After Modern Radiation Therapy for Hodgkin Lymphoma

    Maraldo, M.V.; Brodin, Nils Patrik; Aznar, Marianne Camille;

    2013-01-01

    Hodgkin lymphoma (HL) survivors are at an increased risk of stroke because of carotid artery irradiation. However, for early-stage HL involved node radiation therapy (INRT) reduces the volume of normal tissue exposed to high doses. Here, we evaluate 3-dimensional conformal radiation therapy (3D-C...

  6. Optimisation of conformal radiation therapy by intensity modulation Cancer of the larynx and salivary gland function

    Purpose: Prevention of damage to critical normal tissues is of paramount importance for the quality of life of patients irradiated for cancers in the head and neck. The purpose of this paper was to evaluate the parotid gland sparing 3D conformal radiation therapy technique (3DCRT) in a prospective study in node negative cancer of the larynx. Materials and methods: Twenty-six patients with node negative squamous cell cancer of the larynx were irradiated by a 3DCRT technique (class solution) to both sides of the neck (elective dose 46 Gy to levels II, III and IV) and primary tumour (70 Gy). Dose distributions of the major salivary glands were correlated with objective (stimulated whole saliva flow, WS) and subjective (questionnaire; visual analogue scale, VAS) salivary gland function. Apart from the clinically used 3DCRT technique, in order to optimise 3DCRT dose distributions, intensity modulated (IMRT) treatment plans were generated for the same patient population. Dose-volume histograms of 3DCRT and IMRT treatment plans were analysed and compared. Results: For the 26 patients irradiated with the 3DCRT class solution technique: VAS scores and questionnaires reached their nadir 3 months post-radiotherapy; WS reached its nadir 6 months post-radiotherapy. WS flow rates improved significantly, but never normalised; 2 years post-treatment WS measurements were 48% of the pre-treatment values. VAS scores deteriorated during ERT from 0 pre-treatment to 6.1 immediately post-treatment. Compared to pre-treatment, questionnaires were answered affirmative by increasing numbers of patients. For all patients, IMRT treatment plans resulted in a significant reduction of the dose delivered to the parotid glands compared to the 3DCRT-treatment technique. Conclusions: The class solution for the 3DCRT salivary gland sparing technique is inadequate for fully preserving salivary gland function, given the dose distributions (DVHs) as well as the subjective- and objective salivary gland

  7. MRI definition of target volumes using fuzzy logic method for three-dimensional conformal radiation therapy

    Purpose: Three-dimensional (3D) volume determination is one of the most important problems in conformal radiation therapy. Techniques of volume determination from tomographic medical imaging are usually based on two-dimensional (2D) contour definition with the result dependent on the segmentation method used, as well as on the user's manual procedure. The goal of this work is to describe and evaluate a new method that reduces the inaccuracies generally observed in the 2D contour definition and 3D volume reconstruction process. Methods and Materials: This new method has been developed by integrating the fuzziness in the 3D volume definition. It first defines semiautomatically a minimal 2D contour on each slice that definitely contains the volume and a maximal 2D contour that definitely does not contain the volume. The fuzziness region in between is processed using possibility functions in possibility theory. A volume of voxels, including the membership degree to the target volume, is then created on each slice axis, taking into account the slice position and slice profile. A resulting fuzzy volume is obtained after data fusion between multiorientation slices. Different studies have been designed to evaluate and compare this new method of target volume reconstruction and a classical reconstruction method. First, target definition accuracy and robustness were studied on phantom targets. Second, intra- and interobserver variations were studied on radiosurgery clinical cases. Results: The absolute volume errors are less than or equal to 1.5% for phantom volumes calculated by the fuzzy logic method, whereas the values obtained with the classical method are much larger than the actual volumes (absolute volume errors up to 72%). With increasing MRI slice thickness (1 mm to 8 mm), the phantom volumes calculated by the classical method are increasing exponentially with a maximum absolute error up to 300%. In contrast, the absolute volume errors are less than 12% for phantom

  8. A novel conformity index for intensity modulated radiation therapy plan evaluation

    Purpose: Intensity modulated radiation therapy (IMRT) has gained popularity in the treatment of cancers. Manual evaluation of IMRT plans for head-and-neck cancers has been especially challenging necessitating efficient and objective assessment tools. In this work, the authors address this issue by developing a personalized conformity index (CI) for comparison of IMRT plans for head-and-neck cancers and evaluating its plan quality discerning power in comparison with other widely used CIs. Methods: A two-dimensional CI with dose and distance incorporated (CIDD) was developed using the MATLAB program language, to quantify the planning target volume (PTV) coverage. Valuable information contained in the digital imaging and communication in medicine (DICOM) RT objects were harvested for computation of each of the CIDD components. Apart from the dose penalty factor, a distance-based exponential function was employed by varying the penalty weight associated with the location of cold spots within the PTV. With the goal of deriving a customized penalty factor, the distances between individual pixel and its nearest PTV boundary was found. Using the exponential function, the impact of distance penalty was substantially larger for cold spots closer to the PTV centroid but petered out quickly wherever they were situated in the vicinity of PTV border. In order to evaluate the CIDD scoring system, three CT image data sets of nasopharyngeal carcinoma (NPC) patients were collected. Ten IMRT plans with degrading qualities were generated from each dataset and were ranked based on CIDD and other existing indices. The coefficient of variance was calculated for each dataset to compare the degree of variation. Results: The CIDD scoring system that considered spatial importance of each voxel within the PTV was successfully developed. The results demonstrated that the CIDD including four discrete factors could provide accurate rankings of plan quality by examining the relative importance of

  9. 3-dimensional shaped aluminium foam sandwiches

    Baumeister, J. [Fraunhofer-Institut fuer Fertigungstechnik und Angewandte Materialforschung, Bremen (Germany); Baumgaertner, F. [Schunk Sintermetalltechnik, Giessen (Germany); Gers, H. [Honsel AG, Meschede (Germany); Seeliger, W. [Wilhelm Karmann GmbH, Osnabrueck (Germany)

    2000-07-01

    3-dimensional shaped sandwich panels with a very high stiffness can be produced in an elegant way by combining aluminium face sheets with an aluminium foam core. For this, a mixture of aluminium powder and a foaming agent is compressed to a semi-finished product of nearly vanishing porosity by extrusion, powder rolling or hot isostatic pressing. The resulting foamable semi-finished aluminium material is roll clad with sheets of conventional sheet or aluminium. As a result a precursor material is obtained consisting of two face sheets which are metallurgically bonded to the foamable core layer. This sandwich precursor material can be shaped into a 3-dimensional part by conventional techniques, e.g. by stamping or deep drawing. In a final step the foamable precursor material is heated up to the melting point of the core layer thus initiating its expansion into the desired 3-dimensional shaped sandwich structure. The porosity of the foamed core layer is in the range from 80-90% so that the integral density of the sandwich structure can be as low as 0,7 g/cm{sup 3}. The sandwich materials combine the low weight and high bending stiffness with the advantages of the face sheets, i.e. the high strength and weldability. The manufacturing process will be described in detail and the material properties will be shown. Current and future possible applications will be outlined as well as concrete parts produced up to date. (orig.)

  10. Optimizing Collimator Margins for Isotoxically Dose-Escalated Conformal Radiation Therapy of Non-Small Cell Lung Cancer

    Purpose: Isotoxic dose escalation schedules such as IDEAL-CRT [isotoxic dose escalation and acceleration in lung cancer chemoradiation therapy] (ISRCTN12155469) individualize doses prescribed to lung tumors, generating a fixed modeled risk of radiation pneumonitis. Because the beam penumbra is broadened in lung, the choice of collimator margin is an important element of the optimization of isotoxic conformal radiation therapy for lung cancer. Methods and Materials: Twelve patients with stage I-III non-small cell lung cancer (NSCLC) were replanned retrospectively using a range of collimator margins. For each plan, the prescribed dose was calculated according to the IDEAL-CRT isotoxic prescription method, and the absolute dose (D99) delivered to 99% of the planning target volume (PTV) was determined. Results: Reducing the multileaf collimator margin from the widely used 7 mm to a value of 2 mm produced gains of 2.1 to 15.6 Gy in absolute PTV D99, with a mean gain ± 1 standard error of the mean of 6.2 ± 1.1 Gy (2-sided P<.001). Conclusions: For NSCLC patients treated with conformal radiation therapy and an isotoxic dose prescription, absolute doses in the PTV may be increased by using smaller collimator margins, reductions in relative coverage being offset by increases in prescribed dose

  11. Evaluation of organ-specific peripheral doses after 2-dimensional, 3-dimensional and hybrid intensity modulated radiation therapy for breast cancer based on Monte Carlo and convolution/superposition algorithms: Implications for secondary cancer risk assessment

    Background and purpose: To make a comprehensive evaluation of organ-specific out-of-field doses using Monte Carlo (MC) simulations for different breast cancer irradiation techniques and to compare results with a commercial treatment planning system (TPS). Materials and methods: Three breast radiotherapy techniques using 6MV tangential photon beams were compared: (a) 2DRT (open rectangular fields), (b) 3DCRT (conformal wedged fields), and (c) hybrid IMRT (open conformal + modulated fields). Over 35 organs were contoured in a whole-body CT scan and organ-specific dose distributions were determined with MC and the TPS. Results: Large differences in out-of-field doses were observed between MC and TPS calculations, even for organs close to the target volume such as the heart, the lungs and the contralateral breast (up to 70% difference). MC simulations showed that a large fraction of the out-of-field dose comes from the out-of-field head scatter fluence (>40%) which is not adequately modeled by the TPS. Based on MC simulations, the 3DCRT technique using external wedges yielded significantly higher doses (up to a factor 4–5 in the pelvis) than the 2DRT and the hybrid IMRT techniques which yielded similar out-of-field doses. Conclusions: In sharp contrast to popular belief, the IMRT technique investigated here does not increase the out-of-field dose compared to conventional techniques and may offer the most optimal plan. The 3DCRT technique with external wedges yields the largest out-of-field doses. For accurate out-of-field dose assessment, a commercial TPS should not be used, even for organs near the target volume (contralateral breast, lungs, heart)

  12. A novel conformity index for intensity modulated radiation therapy plan evaluation

    Cheung, Fion W. K.; Law, Maria Y. Y. [Department of Clinical Oncology, Queen Elizabeth Hospital, 999077 Hong Kong (Hong Kong) and Department of Health Technology and Informatics, Hong Kong Polytechnic University, 999077 Hong Kong (Hong Kong); Medical Physics and Research Department, Hong Kong Sanatorium and Hospital, 999077 Hong Kong (Hong Kong) and Department of Health Technology and Informatics, Hong Kong Polytechnic University, 999077 Hong Kong (Hong Kong)

    2012-09-15

    Purpose: Intensity modulated radiation therapy (IMRT) has gained popularity in the treatment of cancers. Manual evaluation of IMRT plans for head-and-neck cancers has been especially challenging necessitating efficient and objective assessment tools. In this work, the authors address this issue by developing a personalized conformity index (CI) for comparison of IMRT plans for head-and-neck cancers and evaluating its plan quality discerning power in comparison with other widely used CIs. Methods: A two-dimensional CI with dose and distance incorporated (CI{sub DD}) was developed using the MATLAB program language, to quantify the planning target volume (PTV) coverage. Valuable information contained in the digital imaging and communication in medicine (DICOM) RT objects were harvested for computation of each of the CI{sub DD} components. Apart from the dose penalty factor, a distance-based exponential function was employed by varying the penalty weight associated with the location of cold spots within the PTV. With the goal of deriving a customized penalty factor, the distances between individual pixel and its nearest PTV boundary was found. Using the exponential function, the impact of distance penalty was substantially larger for cold spots closer to the PTV centroid but petered out quickly wherever they were situated in the vicinity of PTV border. In order to evaluate the CI{sub DD} scoring system, three CT image data sets of nasopharyngeal carcinoma (NPC) patients were collected. Ten IMRT plans with degrading qualities were generated from each dataset and were ranked based on CI{sub DD} and other existing indices. The coefficient of variance was calculated for each dataset to compare the degree of variation. Results: The CI{sub DD} scoring system that considered spatial importance of each voxel within the PTV was successfully developed. The results demonstrated that the CI{sub DD} including four discrete factors could provide accurate rankings of plan quality by

  13. A New Approach to 3-Dimensional Fields

    agashe, sadanand

    2016-01-01

    A new approach, using the operator "x d/dx + y d/dy + z d/dz", is introduced for studying 3-dimensional scalar and vector fields. The approach uses a property of the operator which is similar to that of the Laplacian operator, but the operator does not seem to have been used before. Also, the operator requires only once-differentiability of the fields. Using it, a number of new formulas are derived and new proofs given for many classical results such as the Helmholtz theorem, the Poisson form...

  14. 3-dimensional defect TQFTs and their tricategories

    Carqueville, Nils; Schaumann, Gregor

    2016-01-01

    We initiate a systematic study of 3-dimensional `defect' topological quantum field theories, that we introduce as symmetric monoidal functors on stratified and decorated bordisms. For every such functor we construct a tricategory with duals, which is the natural categorification of a pivotal bicategory. This captures the algebraic essence of defect TQFTs, and it gives precise meaning to the fusion of line and surface defects as well as their duality operations. As examples, we discuss how Reshetikhin-Turaev and Turaev-Viro theories embed into our framework, and how they can be extended to defect TQFTs.

  15. NIR Laser Radiation Induced Conformational Changes and Tunneling Lifetimes of High-Energy Conformers of Amino Acids in Low-Temperature Matrices

    Bazso, Gabor; Najbauer, Eszter E.; Magyarfalvi, Gabor; Tarczay, Gyorgy

    2013-06-01

    We review our recent results on combined matrix isolation FT-IR and NIR laser irradiation studies on glycine alanine, and cysteine. The OH and the NH stretching overtones of the low-energy conformers of these amino acids deposited in Ar, Kr, Xe, and N_{2} matrices were irradiated. At the expense of the irradiated conformer, other conformers were enriched and new, high-energy, formerly unobserved conformers were formed in the matrices. This enabled the separation and unambiguous assignment of the vibrational transitions of the different conformers. The main conversion paths and their efficiencies are described qualitatively showing that there are significant differences in different matrices. It was shown that the high-energy conformer decays in the matrix by H-atom tunneling. The lifetimes of the high-energy conformers in different matrices were measured. Based on our results we conclude that some theoretically predicted low-energy conformers of amino acids are likely even absent in low-energy matrices due to fast H-atom tunneling. G. Bazso, G. Magyarfalvi, G. Tarczay J. Mol. Struct. 1025 (Light-Induced Processes in Cryogenic Matrices Special Issue) 33-42 (2012). G. Bazso, G. Magyarfalvi, G. Tarczay J. Phys. Chem. A 116 (43) 10539-10547 (2012). G. Bazso, E. E. Najbauer, G. Magyarfalvi, G. Tarczay J. Phys. Chem. A in press, DOI: 10.1021/jp400196b. E. E. Najbauer, G. Bazso, G. Magyarfalvi, G. Tarczay in preparation.

  16. A 5-Year Investigation of Children's Adaptive Functioning Following Conformal Radiation Therapy for Localized Ependymoma

    Netson, Kelli L.; Conklin, Heather M. [Department of Psychology, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Wu Shengjie; Xiong Xiaoping [Department of Biostatistics, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Merchant, Thomas E., E-mail: thomas.merchant@stjude.org [Division of Radiation Oncology, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2012-09-01

    Purpose: Conformal and intensity modulated radiation therapies have the potential to preserve cognitive outcomes in children with ependymoma; however, functional behavior remains uninvestigated. This longitudinal investigation prospectively examined intelligence quotient (IQ) and adaptive functioning during the first 5 years after irradiation in children diagnosed with ependymoma. Methods and Materials: The study cohort consisted of 123 children with intracranial ependymoma. Mean age at irradiation was 4.60 years (95% confidence interval [CI], 3.85-5.35). Serial neurocognitive evaluations, including an age-appropriate IQ measure and the Vineland Adaptive Behavior Scales (VABS), were completed before irradiation, 6 months after treatment, and annually for 5 years. A total of 579 neurocognitive evaluations were included in these analyses. Results: Baseline IQ and VABS were below normative means (P<.05), although within the average range. Linear mixed models revealed stable IQ and VABS across the follow-up period, except for the VABS Communication Index, which declined significantly (P=.015). Annual change in IQ (-.04 points) did not correlate with annual change in VABS (-.90 to +.44 points). Clinical factors associated with poorer baseline performance (P<.05) included preirradiation chemotherapy, cerebrospinal fluid shunt placement, number and extent of surgical resections, and younger age at treatment. No clinical factors significantly affected the rate of change in scores. Conclusions: Conformal and intensity modulated radiation therapies provided relative sparing of functional outcomes including IQ and adaptive behaviors, even in very young children. Communication skills remained vulnerable and should be the target of preventive and rehabilitative interventions.

  17. Conformational changes in the chromatin structure of human peripheral blood mononuclear cells exposed to low dose radiation

    Ionizing radiations are known to challenge the integrity of the genome by inducing several lesions like double strand breaks, single strand breaks and oxidative base damage in the DNA. Human cells have evolved efficient DNA repair processes in response to DNA damage by which the integrity of genome is maintained. Emerging evidence indicates that various modulations to chromatin structure are centrally important to many aspects of the DNA damage response (DDR). DNA is compacted and packed in the form of chromatin in eukaryotic cells, the basic unit of chromatin is the nucleosome core particle, which consists of ∼ 146 base pairs of DNA wrapped in two left-handed superhelical turns around an octamer of histone proteins. Higher order chromatin packaging acts as a barrier to the detection and repair of DNA damage. Hence, chromatin reorganization is thought to play a crucial role in cellular responses to DNA damage by making damaged sites more accessible to repair as well as transcriptional machinery of the cell. Dynamic light scattering (DLS) is a sensitive and non invasive tool to study the dynamics of biomolecules in solution. Changes in the conformation of chromatin on exposure to gamma radiation were measured in the form of average hydrodynamic diameter of chromatin fragments in irradiated and control cells. In the present study we have used Dynamic Light Scattering (PLS) as a tool to analyze radiation induced conformational changes in the structure of native chromatin in peripheral blood mononuclear cells (PBMCs) at resting stage (G0). Dose response experiments carried out on 10 individuals have shown a significant difference in the average hydrodynamic diameter of chromatin fibers in different dose groups. Our results have also shown significant changes in the chromatin size at low dose groups (25 cGy and 50 cGy) as compared to higher doses. Inter-individual variations in the chromatin dynamics were clearly demonstrated

  18. 3-dimensional bioprinting for tissue engineering applications.

    Gu, Bon Kang; Choi, Dong Jin; Park, Sang Jun; Kim, Min Sup; Kang, Chang Mo; Kim, Chun-Ho

    2016-01-01

    The 3-dimensional (3D) printing technologies, referred to as additive manufacturing (AM) or rapid prototyping (RP), have acquired reputation over the past few years for art, architectural modeling, lightweight machines, and tissue engineering applications. Among these applications, tissue engineering field using 3D printing has attracted the attention from many researchers. 3D bioprinting has an advantage in the manufacture of a scaffold for tissue engineering applications, because of rapid-fabrication, high-precision, and customized-production, etc. In this review, we will introduce the principles and the current state of the 3D bioprinting methods. Focusing on some of studies that are being current application for biomedical and tissue engineering fields using printed 3D scaffolds. PMID:27114828

  19. A dilogarithmic 3-dimensional Ising tetrahedron

    Broadhurst, D J

    1999-01-01

    In 3 dimensions, the Ising model is in the same universality class as unknown analytical nature. In contrast, all single-scale 4-dimensional tetrahedra were reduced, in hep-th/9803091, to special values of exponentially convergent polylogarithms. Combining dispersion relations with the integer-relation finder PSLQ, we find that $C^{Tet}/2^{5/2} = Cl_2(4\\alpha) - Cl_2(2\\alpha)$, with $Cl_2(\\theta):=\\sum_{n>0}\\sin(n\\theta)/n^2$ and 1,000-digit precision and readily yields 50,000 digits of $C^{Tet}$, after transformation to an exponentially convergent sum, akin to those studied in math.CA/9803067. It appears that this 3-dimensional result entails a polylogarithmic ladder beginning with the classical formula for $\\pi/\\sqrt2$, in the manner that 4-dimensional results build on that for $\\pi/\\sqrt3$.

  20. Molecular Signatures in the Prevention of Radiation Damage by the Synergistic Effect of N-Acetyl Cysteine and Qingre Liyan Decoction, a Traditional Chinese Medicine, Using a 3-Dimensional Cell Culture Model of Oral Mucositis

    Maria P. Lambros

    2015-01-01

    Full Text Available Qingre Liyan decoction (QYD, a Traditional Chinese medicine, and N-acetyl cysteine (NAC have been used to prevent radiation induced mucositis. This work evaluates the protective mechanisms of QYD, NAC, and their combination (NAC-QYD at the cellular and transcriptional level. A validated organotypic model of oral mucosal consisting of a three-dimensional (3D cell tissue-culture of primary human keratinocytes exposed to X-ray irradiation was used. Six hours after the irradiation, the tissues were evaluated by hematoxylin and eosin (H and E and a TUNEL assay to assess histopathology and apoptosis, respectively. Total RNA was extracted and used for microarray gene expression profiling. The tissue-cultures treated with NAC-QYD preserved their integrity and showed no apoptosis. Microarray results revealed that the NAC-QYD caused the upregulation of genes encoding metallothioneins, HMOX1, and other components of the Nrf2 pathway, which protects against oxidative stress. DNA repair genes (XCP, GADD45G, RAD9, and XRCC1, protective genes (EGFR and PPARD, and genes of the NFκB pathway were upregulated. Finally, tissue-cultures treated prophylactically with NAC-QYD showed significant downregulation of apoptosis, cytokines and chemokines genes, and constrained damage-associated molecular patterns (DAMPs. NAC-QYD treatment involves the protective effect of Nrf2, NFκB, and DNA repair factors.

  1. A precision cranial immobilization system for conformal stereotactic fractionated radiation therapy

    Purpose: Conformal radiotherapy has been shown to benefit from precision alignment of patient target to therapy beam (1, 6, 13). This work describes an optimized immobilization system for the fractionated treatment of intracranial targets. A study of patient motion demonstrates the high degree of immobilization which is available. Methods and Materials: A system using dental fixation and a thermoplastic mask that relocates on a rigid frame is described. The design permits scanning studies using computed tomography (CT) and magnetic resonance imaging (MR), conventional photon radiotherapy, and high precision stereotactic proton radiotherapy to be performed with minimal repositioning variation. Studies of both intratreatment motion and daily setup reliability are performed on patients under treatment for paranasal sinus carcinoma. Multiple radiographs taken during single treatments provide the basis for a three-dimensional (3D) motion analysis. Additionally, studies of orthogonal radiographs used to setup for proton treatments and verification port films from photon treatments are used to establish day to day patient position variation in routine use. Results: Net 3D patient motion during any treatment is measured to be 0.9 ± 0.4 mm [mean ± standard deviation (SD)] and rotation about any body axis is 0.14 ± 0.67 degrees (mean ± SD). Day-to-day setup accuracy to laser marks is limited to 2.3 mm (mean) systematic error and 1.6 mm (mean) random error. Conclusion: We conclude that the most stringent immobilization requirements of 3D conformal radiotherapy adjacent to critical normal structures can be met with a high precision system such as the one described here. Without the use of pretreatment verification, additional developments in machine and couch design are needed to assure that patient repositioning accuracy is comparable to the best level of patient immobility achievable

  2. Radiation therapy for localized prostate cancer. For high-dose rate conformal brachytherapy

    Kinugawa, Keigo; Jo, Yoshimasa; Morioka, Masaaki; Tanaka, Hiroyoshi; Hiratsuka, Junichi; Imajo, Yoshinari [Kawasaki Medical School, Kurashiki, Okayama (Japan)

    1999-05-01

    Sixteen patients with localized prostate cancer were referred to our clinic for radiation therapy in combination with HDR brachytherapy using Ir-192 pellets between October 1997 and August 1998. The patients were given external beam radiation of 45 Gy to the whole pelvis in combination with an interstitial HDR brachytherapy implant of 3 fractions each delivering 5.5 Gy during two days. Using an implanting device especially designed for HDR, 10-18 applicator needles (17 gauge) were implanted into the prostate using transrectal ultrasound (TRUS) with perineal template guidance under spinal anesthesia. Pathological evaluation was performed at 6 months after treatment. This technique of external beam radiation combined with HDR brachytherapy was well tolerated. Serum prostatic antigen (PSA) levels became normalized in 87.5% of the patients (14 out of 16) within 1-14 months (median 2 months) after the irradiation. No significant intraoperative or perioperative complications occurred, however one patient (6.25%) experienced Grade 3 hematuria. Most of the early complications were otherwise Grade 1 or 2. From prospectively planned prostatic rebiopsies performed at 6 months, we can observe the radiation effects in the pathological findings such as fibrosis, basal cell hyperplasia, bizarre cells and intraductal calcifications. (K.H.)

  3. Three technique for non coplanar conformal field radiation treatment of breast cancer

    The radiation treatment of the breast is a challenge for radio therapists and physicists, because of the proximity of organs at risk such as lung and heart. For many years tangential irradiation technique has been the technique of choice in these cases. A novel technique described by the group Cancer Institute's work of Italian Switzerland, has been employed by us, good results. (Author)

  4. Performance Analysis of 3-Dimensional Turbo Codes

    Rosnes, Eirik

    2011-01-01

    In this work, we consider the minimum distance properties and convergence thresholds of 3-dimensional turbo codes (3D-TCs), recently introduced by Berrou et al.. Here, we consider binary 3D-TCs while the original work of Berrou et al. considered double-binary codes. In the first part of the paper, the minimum distance properties are analyzed from an ensemble perspective, both in the finite-length regime and in the asymptotic case of large block lengths. In particular, we analyze the asymptotic weight distribution of 3D-TCs and show numerically that their typical minimum distance dmin may, depending on the specific parameters, asymptotically grow linearly with the block length, i.e., the 3D-TC ensemble is asymptotically good for some parameters. In the second part of the paper, we derive some useful upper bounds on the dmin when using quadratic permutation polynomial (QPP) interleavers with a quadratic inverse. Furthermore, we give examples of interleaver lengths where an upper bound appears to be tight. The b...

  5. Dosimetric comparison of three dimensional conformal radiation therapy versus intensity modulated radiation therapy in accelerated partial breast irradiation

    Moorthy, S; H S Elhateer; SKD Majumdar; Mohammed, S; Patnaik, R; Narayanamurty

    2016-01-01

    Aim of Study: Breast conserving surgery (BCS) is the standard treatment for stage I and II breast cancer. Multiple studies have shown that recurrences after lumpectomy occur mainly in or near the tumor bed. Use of accelerated partial breast irradiation (APBI) allows for significant reduction in the overall treatment time that results in increasing patient compliance and decreasing healthcare costs. We conducted a treatment planning study to evaluate the role of intensity modulated radiation t...

  6. Radiation resistance measurement method in conforming to ISO and its effects on proof of sterilization

    Sekiguchi, Masayuki [Tokyo Metropolitan Isotope Research Center (Japan)

    1997-09-01

    The radiation resistance of spore forming bacteria (78 strains) renatured by reculture of bioburden (BB) in the injection needle was measured by the same method as the standard resistance distribution of radiation sterilization standardized by ISO (International Organization for Standarization). {gamma}-ray irradiation unit corrected by NPL alanine dosimeter was used. When D value of vegetative cell bacteria and spore forming bacteria were estimated to 1 KGy, the resistance distribution was restructured and the effect on sterile dose was discussed. Average D value of spore forming bacteria (78 strains) was 2.51 KGy. Its value is near average D value (2.48 KGy) of the standard resistance distribution of five BB. The fact indicates that good safety likelihood could be obtained by estimating sterile dose by log method using D value of spore forming bacteria obtained in culture media. (S.Y.)

  7. Radiation resistance measurement method in conforming to ISO and its effects on proof of sterilization

    The radiation resistance of spore forming bacteria (78 strains) renatured by reculture of bioburden (BB) in the injection needle was measured by the same method as the standard resistance distribution of radiation sterilization standardized by ISO (International Organization for Standarization). γ-ray irradiation unit corrected by NPL alanine dosimeter was used. When D value of vegetative cell bacteria and spore forming bacteria were estimated to 1 KGy, the resistance distribution was restructured and the effect on sterile dose was discussed. Average D value of spore forming bacteria (78 strains) was 2.51 KGy. Its value is near average D value (2.48 KGy) of the standard resistance distribution of five BB. The fact indicates that good safety likelihood could be obtained by estimating sterile dose by log method using D value of spore forming bacteria obtained in culture media. (S.Y.)

  8. Involved-Site Image-Guided Intensity Modulated Versus 3D Conformal Radiation Therapy in Early Stage Supradiaphragmatic Hodgkin Lymphoma

    Purpose: Image-guided intensity modulated radiation therapy (IG-IMRT) allows for margin reduction and highly conformal dose distribution, with consistent advantages in sparing of normal tissues. The purpose of this retrospective study was to compare involved-site IG-IMRT with involved-site 3D conformal RT (3D-CRT) in the treatment of early stage Hodgkin lymphoma (HL) involving the mediastinum, with efficacy and toxicity as primary clinical endpoints. Methods and Materials: We analyzed 90 stage IIA HL patients treated with either involved-site 3D-CRT or IG-IMRT between 2005 and 2012 in 2 different institutions. Inclusion criteria were favorable or unfavorable disease (according to European Organization for Research and Treatment of Cancer criteria), complete response after 3 to 4 cycles of an adriamycin- bleomycin-vinblastine-dacarbazine (ABVD) regimen plus 30 Gy as total radiation dose. Exclusion criteria were chemotherapy other than ABVD, partial response after ABVD, total radiation dose other than 30 Gy. Clinical endpoints were relapse-free survival (RFS) and acute toxicity. Results: Forty-nine patients were treated with 3D-CRT (54.4%) and 41 with IG-IMRT (45.6%). Median follow-up time was 54.2 months for 3D-CRT and 24.1 months for IG-IMRT. No differences in RFS were observed between the 2 groups, with 1 relapse each. Three-year RFS was 98.7% for 3D-CRT and 100% for IG-IMRT. Grade 2 toxicity events, mainly mucositis, were recorded in 32.7% of 3D-CRT patients (16 of 49) and in 9.8% of IG-IMRT patients (4 of 41). IG-IMRT was significantly associated with a lower incidence of grade 2 acute toxicity (P=.043). Conclusions: RFS rates at 3 years were extremely high in both groups, albeit the median follow-up time is different. Acute tolerance profiles were better for IG-IMRT than for 3D-CRT. Our preliminary results support the clinical safety and efficacy of advanced RT planning and delivery techniques in patients affected with early stage HL, achieving complete

  9. Involved-Site Image-Guided Intensity Modulated Versus 3D Conformal Radiation Therapy in Early Stage Supradiaphragmatic Hodgkin Lymphoma

    Filippi, Andrea Riccardo, E-mail: andreariccardo.filippi@unito.it [Department of Oncology, University of Torino, Torino (Italy); Ciammella, Patrizia [Radiation Therapy Unit, Department of Oncology and Advanced Technology, ASMN Hospital IRCCS, Reggio Emilia (Italy); Piva, Cristina; Ragona, Riccardo [Department of Oncology, University of Torino, Torino (Italy); Botto, Barbara [Hematology, Città della Salute e della Scienza, Torino (Italy); Gavarotti, Paolo [Hematology, University of Torino and Città della Salute e della Scienza, Torino (Italy); Merli, Francesco [Hematology Unit, ASMN Hospital IRCCS, Reggio Emilia (Italy); Vitolo, Umberto [Hematology, Città della Salute e della Scienza, Torino (Italy); Iotti, Cinzia [Radiation Therapy Unit, Department of Oncology and Advanced Technology, ASMN Hospital IRCCS, Reggio Emilia (Italy); Ricardi, Umberto [Department of Oncology, University of Torino, Torino (Italy)

    2014-06-01

    Purpose: Image-guided intensity modulated radiation therapy (IG-IMRT) allows for margin reduction and highly conformal dose distribution, with consistent advantages in sparing of normal tissues. The purpose of this retrospective study was to compare involved-site IG-IMRT with involved-site 3D conformal RT (3D-CRT) in the treatment of early stage Hodgkin lymphoma (HL) involving the mediastinum, with efficacy and toxicity as primary clinical endpoints. Methods and Materials: We analyzed 90 stage IIA HL patients treated with either involved-site 3D-CRT or IG-IMRT between 2005 and 2012 in 2 different institutions. Inclusion criteria were favorable or unfavorable disease (according to European Organization for Research and Treatment of Cancer criteria), complete response after 3 to 4 cycles of an adriamycin- bleomycin-vinblastine-dacarbazine (ABVD) regimen plus 30 Gy as total radiation dose. Exclusion criteria were chemotherapy other than ABVD, partial response after ABVD, total radiation dose other than 30 Gy. Clinical endpoints were relapse-free survival (RFS) and acute toxicity. Results: Forty-nine patients were treated with 3D-CRT (54.4%) and 41 with IG-IMRT (45.6%). Median follow-up time was 54.2 months for 3D-CRT and 24.1 months for IG-IMRT. No differences in RFS were observed between the 2 groups, with 1 relapse each. Three-year RFS was 98.7% for 3D-CRT and 100% for IG-IMRT. Grade 2 toxicity events, mainly mucositis, were recorded in 32.7% of 3D-CRT patients (16 of 49) and in 9.8% of IG-IMRT patients (4 of 41). IG-IMRT was significantly associated with a lower incidence of grade 2 acute toxicity (P=.043). Conclusions: RFS rates at 3 years were extremely high in both groups, albeit the median follow-up time is different. Acute tolerance profiles were better for IG-IMRT than for 3D-CRT. Our preliminary results support the clinical safety and efficacy of advanced RT planning and delivery techniques in patients affected with early stage HL, achieving complete

  10. Cardiothoracic Applications of 3-dimensional Printing.

    Giannopoulos, Andreas A; Steigner, Michael L; George, Elizabeth; Barile, Maria; Hunsaker, Andetta R; Rybicki, Frank J; Mitsouras, Dimitris

    2016-09-01

    Medical 3-dimensional (3D) printing is emerging as a clinically relevant imaging tool in directing preoperative and intraoperative planning in many surgical specialties and will therefore likely lead to interdisciplinary collaboration between engineers, radiologists, and surgeons. Data from standard imaging modalities such as computed tomography, magnetic resonance imaging, echocardiography, and rotational angiography can be used to fabricate life-sized models of human anatomy and pathology, as well as patient-specific implants and surgical guides. Cardiovascular 3D-printed models can improve diagnosis and allow for advanced preoperative planning. The majority of applications reported involve congenital heart diseases and valvular and great vessels pathologies. Printed models are suitable for planning both surgical and minimally invasive procedures. Added value has been reported toward improving outcomes, minimizing perioperative risk, and developing new procedures such as transcatheter mitral valve replacements. Similarly, thoracic surgeons are using 3D printing to assess invasion of vital structures by tumors and to assist in diagnosis and treatment of upper and lower airway diseases. Anatomic models enable surgeons to assimilate information more quickly than image review, choose the optimal surgical approach, and achieve surgery in a shorter time. Patient-specific 3D-printed implants are beginning to appear and may have significant impact on cosmetic and life-saving procedures in the future. In summary, cardiothoracic 3D printing is rapidly evolving and may be a potential game-changer for surgeons. The imager who is equipped with the tools to apply this new imaging science to cardiothoracic care is thus ideally positioned to innovate in this new emerging imaging modality. PMID:27149367

  11. Estimation of foetal dose and segregation of contributing scatter components during three-dimensional conformal radiation therapy (3DCRT) of a brain tumour during pregnancy

    The aim of this work is to measure the dose to foetus, both in vivo and in vitro, during three-dimensional conformal radiation therapy (3DCRT) in a pregnant patient with a pituitary adenoma. The study was then extended to assess the components contributing to the foetal dose, such as collimator scatter, internal scatter, head leakage, wedge scatter and MLC effect

  12. A practical technique for conformal simulation in radiation therapy of pelvic tumors

    Purpose: A radiological procedure, based on straightforward conventional methods, was used for a demonstration of pelvic anatomy during simulation to precisely delineate the target volume and increase the probabilities of pelvic tumor control. Methods and Materials: Between 1990 and 1993, 450 patients with primary pelvic malignancies underwent external radiotherapy by means of photons, 6-10 MeV, with multiple-field techniques. The simulation was carried out immediately following a pelvic organs opacification (POO) by standard methods. This procedure used a minimal quantity of contrast media (barium sulphate, iodine contrast) and metallic markers to locate directly and simultaneously: (a) small intestine, (b) bladder, (c) rectum, (d) anal canal, (e) bulbous male urethra, and (f) vagina. When all these structures were clearly visualized, the procedure was scored as successfully performed. Results: the sensitivity of procedure was defined as the percentage of successful pelvic organs opacification (POO) carried out in the patients. It was 98% in both women and men. Indirectly, the procedure helped us to locate the prostate, the perineum, and the uterus cervix in the same percentage of patients. Pelvic organs opacification allowed us to document not only the normal position of the pelvic organs tested, but also any variations (ranging from 5% to 40% of cases, after pelvic surgery). Furthermore, POO revealed previously not-reported abnormalities in patients undergoing surgery, mostly rectal stenosis, urinary or anal incontinence, and bladder luxation. The cost of the materials used was $10-15 for each POO, and the time required 5-7 min. The side effects were 7% and not significant. Conclusion: In the simulation phase for multiple-field irradiation techniques, the simultaneous visualization of pelvic organs obtained by POO procedure allows an exact positioning of the isocenter, an accurate shielding of structures, and finally, a reliable conformal therapy. Due to the low

  13. Relationship between radiation induced adaptive response in human fibroblasts and changes in chromatin conformation

    Ya. Belyaev, Igor [Department of Radiation Physics, Biophysics and Ecology, Moscow Engineering Physics Institute, Moscow (Russia); Spivak, Irina M.; Kolman, Ada; Harms-Ringdahl, Mats [Department of Radiobiology, Stockholm University, Stockholm (Sweden)

    1996-11-04

    Chromatin conformation changes in the normal human fibroblasts VH-10 were studied by the method of anomalous viscosity time dependence (AVTD). Gamma-irradiation of cells in a dose range of 0.1-3 Gy caused an increase in maximal viscosity of cell lysates. Conversely, irradiation of cells with low doses of 0.5 or 2 cGy resulted in a decrease in the AVTD peaks with a maximum effect approximately 40 min after irradiation. The same exposure conditions were used to study a possible adaptive effect of low doses, measured by changes in cell survival. A primary dose of 2 cGy caused significant modification of cell response to a challenge dose. Approximately 20% protection to challenge doses of 0.5 Gy (p<0.003), 2 Gy (p<0.02) and 2.5 Gy (p<0.002) was observed. However, the direction of this effect (adaptation or synergism) was found to be dependent on a challenge dose. The combined effect of 2 cGy and 1 Gy was significantly synergistic, while no modification was observed for 1.5 Gy and 3 Gy. A partial correlation was found between the AVTD changes and cell survival when the combined effect of a primary dose of 2 cGy and challenge dose was examined. The dose of 2 cGy alone increased survival by 16% (p<0.0003). These results suggest that the low-dose induced effects on survival may be related to chromatin reorganization.

  14. Comparison of conformal and intensity modulated radiation therapy techniques for treatment of pelvic tumors. Analysis of acute toxicity

    This retrospective analysis reports on the comparative outcome of acute gastrointestinal (GI) and genitourinary (GU) toxicities between conformal radiation therapy (CRT) and intensity modulated radiation therapy (IMRT) techniques in the treatment of patients with pelvic tumors. From January 2002 to December 2008, 69 patients with pelvic tumors underwent whole pelvic CRT and 65 underwent whole pelvic IMRT to treat pelvic lymph nodes and primary tumor regions. Total dose to the whole pelvis ranged from 50 to 50.4 Gy in 25 to 28 daily fractions. Chemotherapy (CT) regimen, when employed, was based upon primary tumor. Acute GI and GU toxicities were graded by RTOG/EORTC acute radiation morbidity criteria. Absence of GI symptoms during radiotherapy (grade 0) was more frequently observed in the IMRT group (43.1% versus 8.7; p < 0.001) and medication for diarrhea (Grade 2) was more frequently used in the CRT group (65.2% versus 38.5%; p = 0.002). Acute GI grade 1 and 3 side effects incidence was similar in both groups (18.5% versus 18.8%; p = 0.95 and 0% versus 7.2%; p = 0.058, respectively). Incidence of GU toxicity was similar in both groups (grade 0: 61.5% versus 66.6%, p = 0.54; grade 1: 20% versus 8.7%, p = 0.06; grade 2: 18.5% versus 23.5%, p = 0.50 and grade 3: 0% versus 1.5%, p > 0.99). This comparative case series shows less grade 2 acute GI toxicity in patients treated with whole pelvic IMRT in comparison with those treated with CRT. Incidence of acute GU toxicity was similar in both groups

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

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

    2012-11-15

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

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

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

  17. An investigation on the radiation sensitivity of DNA conformations to 60Co gamma rays by using Geant4 toolkit

    To investigate the impact of conformational properties of genetic material of living cells on radiation-induced DNA damage, single strand breaks (SSB), double strand breaks (DSB) and some microdosimetric quantities of A, B and Z-DNA conformations caused by 60Co gamma rays, have been calculated. Based on a previous B-DNA geometrical model, models of A and Z forms have been developed. Simple 34 base pairs segments of each model repeated in high number and secondary electron spectrum of 60Co gamma rays have been simulated in a volume of a typical animal cell nucleus. All simulations in this study have been performed by using the Geant4 (GEometry ANd Tracking 4)-DNA extension of the Geant4 toolkit. The results showed that, B-DNA has the lowest yield of simple strand breaks with 2.23 × 10−10 Gy−1 Da−1 and 1.0 × 10−11 Gy−1 Da−1 for the SSB and DSB damage yield, respectively. The A-DNA has the highest SSB yield with 3.59 × 10−10 Gy−1 Da−1 and the Z-DNA has the highest DSB yields with 1.8 × 10−11 Gy−1 Da−1. It has been concluded that there is a direct correlation between the hit probability, mean specific imparted energy and SSB yield in each model of DNA. Moreover, there is a direct correlation between the DSB yield and both the mean lineal energy and topological characteristics of each model

  18. An investigation on the radiation sensitivity of DNA conformations to {sup 60}Co gamma rays by using Geant4 toolkit

    Semsarha, F. [Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box 13145-1384, Tehran (Iran, Islamic Republic of); Goliaei, B., E-mail: goliaei@ibb.ut.ac.ir [Institute of Biochemistry and Biophysics (IBB), University of Tehran, P.O. Box 13145-1384, Tehran (Iran, Islamic Republic of); Raisali, G.; Khalafi, H. [Radiation Applications Research School, Nuclear Science and Technology Research Institute, P.O. Box 11365-3486, Tehran (Iran, Islamic Republic of); Mirzakhanian, L. [Medical Physics Unit, McGill University, 1650 Cedar Avenue, Montreal, Quebec (Canada)

    2014-03-15

    To investigate the impact of conformational properties of genetic material of living cells on radiation-induced DNA damage, single strand breaks (SSB), double strand breaks (DSB) and some microdosimetric quantities of A, B and Z-DNA conformations caused by {sup 60}Co gamma rays, have been calculated. Based on a previous B-DNA geometrical model, models of A and Z forms have been developed. Simple 34 base pairs segments of each model repeated in high number and secondary electron spectrum of {sup 60}Co gamma rays have been simulated in a volume of a typical animal cell nucleus. All simulations in this study have been performed by using the Geant4 (GEometry ANd Tracking 4)-DNA extension of the Geant4 toolkit. The results showed that, B-DNA has the lowest yield of simple strand breaks with 2.23 × 10{sup −10} Gy{sup −1} Da{sup −1} and 1.0 × 10{sup −11} Gy{sup −1} Da{sup −1} for the SSB and DSB damage yield, respectively. The A-DNA has the highest SSB yield with 3.59 × 10{sup −10} Gy{sup −1} Da{sup −1} and the Z-DNA has the highest DSB yields with 1.8 × 10{sup −11} Gy{sup −1} Da{sup −1}. It has been concluded that there is a direct correlation between the hit probability, mean specific imparted energy and SSB yield in each model of DNA. Moreover, there is a direct correlation between the DSB yield and both the mean lineal energy and topological characteristics of each model.

  19. Three dimensional conformal radiation therapy planning in the evaluation of post-operative prophylactic irradiation fields for esophageal carcinoma

    Objective: Evaluation of the dose distribution in esophageal bed region was carried out with prophylactic irradiation fields after esophagectomy by three dimensional conformal radiation therapy planning . Methods: From 2001 to 2003, 38 esophageal cancer patients who had received radical esophagectomy were given chest CT scanning and reconstruction of organs and contours by the three-dimensional conformal treatment planning system. Design of the anterior, posterior vertical and double horizontal lateral fields was made. For each patient, double pattern irradiation was adopted as three (Anterior, Left, Right) or four (A, P, L, R) fields. The field sizes were 7 cm x 22 cm and 6 cm x 22 cm or 7 cm x 18 cm and 6 cm x 18 cm. According to dose weight of each field in the irradiated field of the same length, these patients were again divided into eight groups to compare the mean value of maximum dose, minimum dose and mean dose in the esophageal bed target and also to compare the maximum dose, mean dose and the mean value of dose volume on the spinal cord and, simultaneously, the V20, V15 of bilateral lungs in the different groups. Results: When the length of the field increased, the uniformity of dose distribution in the esophageal bed target became poor, with the mean value of maximum dose in the spinal cord also increased. The dose distribution of four irradiation fields was better than of three fields, with inconspicuous increase in the mean value of maximum dose of spinal cord. However there was insignificant difference in V20, V15 no matter four or three fields were used. Conclusion: The authors recommend that four irradiation fields be used rather than three fields for esophageal carcinoma postoperative prophylactic irradiation. For prescription dose of 50 Gy , the dose weight in each field should be 18, 16 Gy or 18,18 Gy for anterior and posterior fields; 8, 8 Gy or 7, 7 Gy for double horizontal lateral fields

  20. 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

    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

  1. Dose computation in conformal radiation therapy including geometric uncertainties: Methods and clinical implications

    Rosu, Mihaela

    The aim of any radiotherapy is to tailor the tumoricidal radiation dose to the target volume and to deliver as little radiation dose as possible to all other normal tissues. However, the motion and deformation induced in human tissue by ventilatory motion is a major issue, as standard practice usually uses only one computed tomography (CT) scan (and hence one instance of the patient's anatomy) for treatment planning. The interfraction movement that occurs due to physiological processes over time scales shorter than the delivery of one treatment fraction leads to differences between the planned and delivered dose distributions. Due to the influence of these differences on tumors and normal tissues, the tumor control probabilities and normal tissue complication probabilities are likely to be impacted upon in the face of organ motion. In this thesis we apply several methods to compute dose distributions that include the effects of the treatment geometric uncertainties by using the time-varying anatomical information as an alternative to the conventional Planning Target Volume (PTV) approach. The proposed methods depend on the model used to describe the patient's anatomy. The dose and fluence convolution approaches for rigid organ motion are discussed first, with application to liver tumors and the rigid component of the lung tumor movements. For non-rigid behavior a dose reconstruction method that allows the accumulation of the dose to the deforming anatomy is introduced, and applied for lung tumor treatments. Furthermore, we apply the cumulative dose approach to investigate how much information regarding the deforming patient anatomy is needed at the time of treatment planning for tumors located in thorax. The results are evaluated from a clinical perspective. All dose calculations are performed using a Monte Carlo based algorithm to ensure more realistic and more accurate handling of tissue heterogeneities---of particular importance in lung cancer treatment planning.

  2. Comparison of 3D conformal radiotherapy vs. intensity modulated radiation therapy (IMRT) of a stomach cancer treatment;Comparacion dosimetrica de radioterapia conformal 3D versus radioterapia de intensidad modulada (IMRT) de un tratamiento de cancer de estomago

    Bernui de V, Maria Giselle; Cardenas, Augusto; Vargas, Carlos [Hospital Nacional Carlos Alberto Seguin Escobedo (ESSALUD), Arequipa (Peru). Servicio de Radioterapia

    2009-07-01

    The purpose of this work was to compare the dosimetry in 3D Conformal Radiotherapy with Intensity Modulated Radiation Therapy (IMRT) in a treatment of stomach cancer. For this comparison we selected a patient who underwent subtotal gastrectomy and D2 dissection for a T3N3 adenocarcinoma Mx ECIIIB receiving treatment under the scheme Quimio INT 0116 - in adjuvant radiotherapy. In the treatment plan was contouring the Clinical Target Volume (CTV) and the Planning Target Volume (PTV) was generated from the expansion of 1cm of the CTV, the risky organs contouring were: the liver, kidneys and spinal cord, according to the consensus definition of volumes in gastric cancer. The 3D Conformal Radiotherapy planning is carried out using 6 half beams following the Leong Trevol technique; for the IMRT plan was used 8 fields, the delivery technique is step-and-shoot. In both cases the fields were coplanar, isocentric and the energy used was 18 MV. Intensity Modulated Radiation Therapy (IMRT), in this case has proved to be a good treatment alternative to the technique of 3D Conformal Radiotherapy; the dose distributions with IMRT have better coverage of PTV and positions of the hot spots, as well as the kidneys volume that received higher doses to 2000 cGy is lower, but the decrease in dose to the kidneys is at the expense of increased dose in other organs like the liver. (author)

  3. Lithographically defined 3-dimensional graphene scaffolds

    Burckel, D. Bruce; Xiao, Xiaoyin; Polsky, Ronen

    2015-09-01

    Interferometrically defined 3D photoresist scaffolds are formed through a series of three successive two-beam interference exposures, a post exposure bake and development. Heating the resist scaffold in a reducing atmosphere to > 1000 °C, results in the conversion of the resist structure into a carbon scaffold through pyrolysis, resulting in a 3D sp3- bonded glassy carbon scaffold which maintains the same in-plane morphology as the resist despite significant shrinkage. The carbon scaffolds are readily modified using a variety of deposition methods such as electrochemical, sputtering and CVD/ALD. Remarkably, sputtering metal into scaffolds with ~ 5 unit cells tall results in conformal coating of the scaffold with the metal. When the metal is a transition metal such as nickel, the scaffold can be re-annealed, during which time the carbon diffuses through the nickel, emerging on the exterior of the nickel as sp2-bonded carbon, termed 3D graphene. This paper details the fabrication, characterization and some potential applications for these structures.

  4. A study on quantitative analysis of field size and dose by using gating system in 4D conformal radiation treatment

    Ji, Youn-Sang; Dong, Kyung-Rae; Kim, Chang-Bok; Chung, Woon-Kwan; Cho, Jae-Hwan; Lee, Hae-Kag

    2012-10-01

    This study evaluated the gating-based 4-D conformal radiation therapy (4D-CT) treatment planning by a comparison with the common 3-D conformal radiation therapy (3D-CT) treatment planning and examined the change in treatment field size and dose to the tumors and adjacent normal tissues because an unnecessary dose is also included in the 3-D treatment planning for the radiation treatment of tumors in the chest and abdomen. The 3D-CT and gating-based 4D-CT images were obtained from patients who had undergone radiation treatment for chest and abdomen tumors in the oncology department. After establishing a treatment plan, the CT treatment and planning system were used to measure the change in field size for analysis. A dose volume histogram (DVH) was used to calculate the appropriate dose to planning target volume (PTV) tumors and adjacent normal tissue. The difference in the treatment volume of the chest was 0.6 and 0.83 cm on the X- and Y-axis, respectively, for the gross tumor volume (GTV). Accordingly, the values in the 4D-CT treatment planning were smaller and the dose was more concentrated by 2.7% and 0.9% on the GTV and clinical target volume (CTV), respectively. The normal tissues in the surrounding normal tissues were reduced by 3.0%, 7.2%, 0.4%, 1.7%, 2.6% and 0.2% in the bronchus, chest wall, esophagus, heart, lung and spinal cord, respectively. The difference in the treatment volume of the abdomen was 0.72 cm on the X-axis and 0.51 cm on the Y-axis for the GTV; and 1.06 cm on the X-axis and 1.85 cm on the Y-axis for the PTV. Therefore, the values in the 4D-CT treatment planning were smaller. The dose was concentrated by 6.8% and 4.3% on the GTV and PTV, respectively, whereas the adjacent normal tissues in the cord, Lt. kidney, Rt. kidney, small bowels and whole liver were reduced by 3.2%, 4.2%, 1.5%, 6.2% and 12.7%, respectively. The treatment field size was smaller in volume in the case of the 4D-CT treatment planning. In the DVH, the 4D-CT treatment

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

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

  6. Lyman NTCP model analysis of radiation-induced liver disease in hypofractionated conformal radiotherapy for primary liver carcinoma

    Objective: To identify the factors associated with radiation-induced liver disease (RILD) and to describe the probability of RILD using the Lyman normal tissue complication(NTCP) model for primary liver carcinoma(PLC) treated with hypofractionated conformal therapy (CRT). Methods: A total of 109 PLC patients treated with hypofractionated CRT were prospectively followed according to the Child-Pugh classification for liver cirrhosis, 93 patients in class A and 16 in class B. The mean dose of radiation to the isocenter was (53.5±5.5) Gy, fractions of (4.8±0.5) Gy, with interfraction interval of 48 hours and irradiation 3 times per week. Maximal likelihood analysis yielded the best estimates of parameters of the Lyman NTCP model for all patients; Child-Pugh A and Child-Pugh B patients, respectively. Results: Of all the patients, 17 developed RILD (17/109), 8 in Child-Pugh A (8/93) and 9 in Child-Pugh B (9/16). By multivariate analysis, only the Child-Pugh Grade of liver cirrhosis was the independent factor (P=0.000) associated with the developing of BILD. The best estimates of the NTCP parameters for all 109 patients were n=1.1, m=0.35 and TD50 (1)=38.5 Gy. The n, m, TD50 (1) estimated from patients with Child-Pugh A was 1.1, 0.28, 40.5 Gy, respectively, compared with 0.7, 0.43, 23 Gy respectively, for patients with Child-Pugh B. Conclusions: Primary liver cancer patients who possess Child-Pugh B cirrhosis would present a significantly greater susceptibility to RILD after hypofractionated CRT than patients with Child-Pugh A cirrhosis. The predominant risk factor for developing RILD is the severity of hepatic cirrhosis in the liver of PLC patients. (authors)

  7. 3-dimensional analysis of FELIX brick with hole

    Electromagnetic induction on FELIX brick with a hole has been analyzed with 3-Dimensional EDDYNET computer code. Incorporating loop currents on hexahedral meshes, the 3-Dimensional EDDYNET program solves eddy current problems by a network approach, and provides good accuracy even for coarse meshes. (author)

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

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

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

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

    2011-11-15

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

  10. Changes in beta-lactoglobulin conformation at the oil/water interface of emulsions studied by synchrotron radiation circular dichroism spectroscopy.

    Zhai, Jiali; Miles, Andrew J; Pattenden, Leonard Keith; Lee, Tzong-Hsien; Augustin, Mary Ann; Wallace, B A; Aguilar, Marie-Isabel; Wooster, Tim J

    2010-08-01

    The structure of proteins at interfaces is a key factor determining the stability as well as organoleptic properties of food emulsions. While it is widely believed that proteins undergo conformational changes at interfaces, the measurement of these structural changes remains a significant challenge. In this study, the conformational changes of beta-lactoglobulin (beta-Lg) upon adsorption to the interface of hexadecane oil-in-water emulsions were investigated using synchrotron radiation circular dichroism (SRCD) spectroscopy. Far-UV SRCD spectra showed that adsorption of beta-Lg to the O/W interface caused a significant increase in non-native alpha-helix structure, accompanied by a concomitant loss of beta-sheet structure. Near-UV SRCD spectra revealed that a considerable disruption of beta-Lg tertiary structure occurred upon adsorption. Moreover, heat-induced changes to the non-native beta-Lg conformation at the oil/water interface were very small compared to the dramatic loss of beta-Lg secondary structure that occurred during heating in solution, suggesting that the interface has a stabilizing effect on the structure of non-native beta-Lg. Overall, our findings provide insight into the conformational behavior of proteins at oil/water interfaces and demonstrate the applicability of SRCD spectroscopy for measuring the conformation of adsorbed proteins in optically turbid emulsions. PMID:20690721

  11. Single-arm phase II study of conformal radiation therapy and temozolomide plus fractionated stereotactic conformal boost in high-grade gliomas. Final report

    Balducci, Mario; Manfrida, Stefania; Mangiola, Annunziato; Fiorentino, Alba; D' Agostino, Giuseppe Roberto; Frascino, Vincenzo; Dinapoli, Nicola; Mantini, Giovanna; Albanese, Alessio; De Bonis, Pasquale; Chiesa, Silvia; Valentini, Vincenzo; Anile, Carmelo; Cellini, Numa [Dept. of Radiotherapy, Catholic Univ. of the Sacred Heart, Rome (Italy); Apicella, Giuseppina [Dept. of Radiotherapy, Catholic Univ. of the Sacred Heart, Rome (Italy); Dept. of Radiotherapy, Univ. Hospital Maggiore della Carita, Novara (Italy); Azario, Luigi [Dept. of Physics, Catholic Univ. of the Sacred Heart, Rome (Italy)

    2010-10-15

    Purpose: To assess survival, local control and toxicity using fractionated stereotactic conformal radiotherapy (FSCRT) boost and temozolomide in high-grade gliomas (HGGs). Patients and Methods: Patients affected by HGG, with a CTV{sub 1} (clinical target volume, representing tumor bed {+-} residual tumor + a margin of 5 mm) {<=} 8 cm were enrolled into this phase II study. Radiotherapy (RT, total dose 6,940 cGy) was administered using a combination of two different techniques: three-dimensional conformal radiotherapy (3D-CRT, to achieve a dose of 5,040 or 5,940 cGy) and FSCRT boost (19 or 10 Gy) tailored by CTV{sub 1} diameter ({<=} 6 cm and > 6 cm, respectively). Temozolomide (75 mg/m{sup 2}) was administered during the first 2 or 4 weeks of RT, After the end of RT, temozolomide (150-200 mg/m{sup 2}) was administered for at least six cycles. The sample size of 41 patients was assessed by the single proportion-powered analysis. Results: 41 patients (36 with glioblastoma multiforme [GBM] and five with anaplastic astrocytoma [AA]) were enrolled; RTOG neurological toxicities G1-2 and G3 were 12% and 3%, respectively. Two cases of radionecrosis were observed. At a median follow-up of 44 months (range 6-56 months), global and GBM median overall survival (05) were 30 and 28 months. The 2-year survival rate was significantly better compared to the standard treatment (63% vs. 26.5%; p < 0.00001). Median progression-free survival (PFS) was 11 months, in GBM patients 10 months. Conclusion: FSCRT boost plus temozolomide is well tolerated and seems to increase survival compared to the standard treatment in patients with HGG. (orig.)

  12. Analysis of dose-volume parameters predicting radiation pneumonitis in patients with esophageal cancer treated with 3D-conformal radiation therapy or IMRT

    Multimodality therapy for esophageal cancer can cause various kinds of treatment-related sequelae, especially pulmonary toxicities. This prospective study aims to investigate the clinical and dosimetric parameters predicting lung injury in patients undergoing radiation therapy for esophageal cancer. Forty-five esophageal cancer patients were prospectively analyzed. The pulmonary toxicities (or sequelae) were evaluated by comparing chest X-ray films, pulmonary function tests and symptoms caused by pulmonary damage before and after treatment. All patients were treated with either three-dimensional radiotherapy (3DCRT) or with intensity-modulated radiotherapy (IMRT). The planning dose volume histogram was used to compute the lung volumes receiving more than 5, 10, 20 and 30 Gy (V5, V10, V20, V30) and mean lung dose. V20 was larger in the IMRT group than in the 3DCRT group (p=0.002). V20 (>15%) and V30 (>20%) resulted in a statistically significant increase in the occurrence of chronic pneumonitis (p=0.03) and acute pneumonitis (p=0.007), respectively. The study signifies that a larger volume of lung receives lower doses because of multiple beam arrangement and a smaller volume of lung receives higher doses because of better dose conformity in IMRT plans. Acute pneumonitis correlates more with V30 values, whereas chronic pneumonitis was predominantly seen in patients with higher V20 values. (author)

  13. Whole breast and excision cavity radiotherapy plan comparison: Conformal radiotherapy with sequential boost versus intensity-modulated radiation therapy with a simultaneously integrated boost

    Small, Katherine; Kelly, Chris; Beldham-Collins, Rachael; Gebski, Val

    2013-01-01

    Introduction A comparative study was conducted comparing the difference between (1) conformal radiotherapy (CRT) to the whole breast with sequential boost excision cavity plans and (2) intensity-modulated radiation therapy (IMRT) to the whole breast with simultaneously integrated boost to the excision cavity. The computed tomography (CT) data sets of 25 breast cancer patients were used and the results analysed to determine if either planning method produced superior plans. Methods CT data set...

  14. Does hormonal therapy influence sexual function in men receiving 3D conformal radiation therapy for prostate cancer?

    Purpose: We evaluated the effect of three-dimensional conformal radiation therapy (3D-CRT) with or without hormonal therapy (HT) on sexual function (SF) in prostate cancer patients whose SF was known before all treatment. Methods and Materials: Between March 1996 and March 1999, 144 patients received 3D-CRT (median dose = 70.2 Gy, range 66.6-79.2 Gy) for prostate cancer and had pre- and post-therapy SF data. All SF data were obtained with the O'Leary Brief SF Inventory, a self-administered, multidimensional, validated instrument. We defined total sexual potency as erections firm enough for penetration during intercourse. Mean follow-up time was 21 months (SD ± 11 months). The Wilcoxon signed-rank test was used to test for significance of the change from baseline. Results: Before 3D-CRT, 87 (60%) of 144 men were totally potent as compared to only 47 (47%) of 101 at 1-year follow-up. Of the 60 men totally potent at baseline and followed for at least 1 year, 35 (58%) remained totally potent. These changes corresponded to a significant reduction in SF (p<0.05). Patients who had 3D-CRT alone were more likely to be totally potent at 1 year than those receiving 3D-CRT with HT (56% vs. 31%, p=0.012); however, they were also more likely to be potent at baseline (71% vs. 44%, p=0.001). Although these two groups had a significant reduction in SF from baseline, their change was not significantly different from each other. Conclusion: These data indicate that 3D-CRT causes a significant reduction in total sexual potency as compared to pretreatment baseline. The addition of HT does not appear to increase the risk of sexual dysfunction

  15. Quality assurance of 3-D conformal radiation therapy for a cooperative group trial - RTOG 3D QA center initial experience

    PURPOSE: 3-D conformal radiation therapy (3DCRT) holds promise in allowing safe escalation of radiation dose to increase the local control of prostate cancer. Prospective evaluation of this new modality requires strict quality assurance (QA). We report the results of QA review on patients receiving 3DCRT for prostate cancer on a cooperative group trial. MATERIALS and METHODS: In 1993 the NCI awarded the ACR/RTOG and nine institutions an RFA grant to study the use of 3DCRT in the treatment of prostate cancer. A phase I/II trial was developed to: a) test the feasibility of conducting 3DCRT radiation dose escalation in a cooperative group setting; b) establish the maximum tolerated radiation dose that can be delivered to the prostate; and c) quantify the normal tissue toxicity rate when using 3DCRT. In order to assure protocol compliance each participating institution was required to implement data exchange capabilities with the RTOG 3D QA center. The QA center reviews at a minimum the first five case from each participating center and spot checks subsequent submissions. For each case review the following parameters are evaluated: 1) target volume delineation, 2) normal structure delineation, 3) CT data quality, 4) field placement, 5) field shaping, and 6) dose distribution. RESULTS: Since the first patient was registered on August 23, 1994, an additional 170 patients have been accrued. Each of the nine original approved institutions has participated and three other centers have recently passed quality assurance bench marks for study participation. Eighty patients have been treated at the first dose level (68.4 Gy minimum PTV dose) and accrual is currently ongoing at the second dose level (73.8 Gy minimum PTV dose). Of the 124 cases that have undergone complete or partial QA review, 30 cases (24%) have had some problems with data exchange. Five of 67 CT scans were not acquired by protocol standards. Target volume delineation required the submitting institution

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

    Öğretici, Akın; Akbaş, Uğur; Köksal, Canan; Bilge, Hatice

    2016-01-01

    The aim of this research was to investigate the fetal doses of pregnant patients undergoing conformal radiotherapy or intensity-modulated radiation therapy (IMRT) for breast cancers. An Alderson Rando phantom was chosen to simulate a pregnant patient with breast cancer who is receiving radiation therapy. This phantom was irradiated using the Varian Clinac DBX 600 system (Varian Medical System, Palo Alto, CA) linear accelerator, according to the standard treatment plans of both three-dimensional conformal radiation therapy (3-D CRT) and IMRT techniques. Thermoluminescent dosimeters were used to measure the irradiated phantom׳s virtually designated uterus area. Thermoluminescent dosimeter measurements (in the phantom) revealed that the mean cumulative fetal dose for 3-D CRT is 1.39cGy and for IMRT it is 8.48cGy, for a pregnant breast cancer woman who received radiation treatment of 50Gy. The fetal dose was confirmed to increase by 70% for 3-D CRT and 40% for IMRT, if it is closer to the irradiated field by 5cm. The mean fetal dose from 3-D CRT is 1.39cGy and IMRT is 8.48cGy, consistent with theoretic calculations. The IMRT technique causes the fetal dose to be 5 times more than that of 3-D CRT. Theoretic knowledge concerning the increase in the peripheral doses as the measurements approached the beam was also practically proven. PMID:26831923

  17. An evaluation of three dimensional conformal radiation therapy versus intensity modulated radiation therapy in radical chemoradiation of esophageal cancer: A dosimetric study

    Soumik Ghosh

    2012-01-01

    Full Text Available Aims: To evaluate the feasibility whether intensity-modulated radiotherapy (IMRT can be used to reduce doses to normal thoracic structures than three-dimensional conformal radiotherapy (3DCRT in treating esophageal cancer and to compare normal tissue complication probability (NTCP for lung between two treatment plans. Materials and Methods: A prospective study was carried out from 2009 to 2011, in which 15 inoperable patients of esophageal cancer who were suitable for radical chemoradiation were enrolled. All patients were treated with 3DCRT. In first phase, patients were treated with external beam radiation therapy (EBRT dose of 36Gy in 20 fractions in 4 weeks, along with concurrent weekly chemotherapy with cisplatinum and 5-fluorouracil (5 FU. In second phase, boost dose of 18Gy in 10 fractions in 2 weeks was given. An IMRT plan was generated for each patient. Plan sum of both the 3D CRT and IMRT plans were compared. Doses to critical structures and NTCP for lung were compared between 3DCRT and IMRT plans. Results: The mean lung dose and volumes of lung receiving 20 Gy, 10 Gy, and 5 Gy (V20, V10, and V5 were significantly lower with 3DCRT plans as compared to IMRT plans. The mean dose to heart and spinal cord was higher in 3DCRT arm. There was no difference in dose distribution to the liver between the 3D CRT and IMRT techniques. The NTCP for lung was lower with 3D CRT than IMRT. Conclusion: IMRT technique needs further dosimetric study as well as further clinical trials before implication of this technique replacing 3D CRT technique with escalated dose for the treatment of esophageal cancer in our setup. IMRT using seven fields provided no improvement over 3DCRT.

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

    Background and purpose: We fit phenomenological tumor control probability (TCP) models to biopsy outcome after three-dimensional conformal radiation therapy (3D-CRT) of prostate cancer patients to quantify the local dose-response of prostate cancer. Materials and methods: We analyzed the outcome after photon beam 3D-CRT of 103 patients with stage T1c-T3 prostate cancer treated at Memorial Sloan-Kettering Cancer Center (MSKCC) (prescribed target doses between 64.8 and 81 Gy) who had a prostate biopsy performed ≥2.5 years after end of treatment. A univariate logistic regression model based on Dmean (mean dose in the planning target volume of each patient) was fit to the whole data set and separately to subgroups characterized by low and high values of tumor-related prognostic factors T-stage (6), and pre-treatment prostate-specific antigen (PSA) (≤10 ng/ml vs. >10 ng/ml). In addition, we evaluated five different classifications of the patients into three risk groups, based on all possible combinations of two or three prognostic factors, and fit bivariate logistic regression models with Dmean and the risk group category to all patients. Dose-response curves were characterized by TCD50, the dose to control 50% of the tumors, and γ50, the normalized slope of the dose-response curve at TCD50. Results: Dmean correlates significantly with biopsy outcome in all patient subgroups and larger values of TCD50 are observed for patients with unfavorable compared to favorable prognostic factors. For example, TCD50 for high T-stage patients is 7 Gy higher than for low T-stage patients. For all evaluated risk group definitions, Dmean and the risk group category are independent predictors of biopsy outcome in bivariate analysis. The fit values of TCD50 show a clear separation of 9-10.6 Gy between low and high risk patients. The corresponding dose-response curves are steeper (γ50=3.4-5.2) than those obtained when all patients are analyzed together (γ50=2.9). Conclusions: Dose

  19. Quality of life following 3D conformal radiation therapy or permanent interstitial brachytherapy for localized prostate cancer

    Purpose: Both 3D Conformal Radiation Therapy (3DCRT) and Transperineal Interstitial Permanent Brachytherapy (TIPPB) are offered as suitable non-surgical alternatives to radical prostatectomy. Despite equivalent cancer control, very little data has been published that compares Quality of Life (QOL) in contemporary cohorts of patients choosing these treatments. Materials and Methods: Since 1998, patients selecting either 3DCRT alone or TIPPB (monotherapy or boost after external beam) for primary management of localized prostate cancer were asked to participate in a prospective assessment of QOL measures. In this preliminary report, 41 3DCRT and 40 TIPPB (34 monotherapy, 6 boost) patients completed validated QOL instruments at each followup visit. QOL instruments included the International Prostate Symptom Score (IPSS), FACT-P, and Sexual Adjustment Questionnaire (SAQ). Results: The average age of men in each group was 69 years. Choice of treatment was left to the patient unless there were significant medical or technical contraindications to either modality. 3DCRT total doses ranged from 61-78 Gy (mean 73.5Gy) and TIPPB doses were 145Gy (TG43) in 34 I-125 implants and 115 Gy in 1 Pd-103 (monotherapy) or 90 Gy in 5 Pd-103 (boost) implants. Patients undergoing TIPPB reported significantly worse urinary and sexual function than their counterparts receiving 3DCRT. The mean cumulative IPSS was 12.5 with TIPPB compared to 8.3 with 3DCRT (p=0.036). Differences were most pronounced in the first 12 months after treatment, particularly with respect to the strength of stream and the need to strain. TIPPB patients were more likely to report a need to urinate frequently (p=0.02), require a pad (p=0.001), be bothered (p=0.02), or have activity limited by urinary side effects (p=0.01). TIPPB patients were less likely to resume sexual activity within 6 months after treatment (p=0.0003) and engaged in sexual activity less often (p= 0.016) than 3DCRT patients. They were also more

  20. 3 dimensional volume MR imaging of intratemporal facial nerve

    Seo, Jeong Jin; Kang, Heoung Keun; Kim, Hyun Ju; Kim, Jae Kyu; Jung, Hyun Ung; Moon, Woong Jae [Chonnam University Medical School, Kwangju (Korea, Republic of)

    1994-10-15

    To evaluate the usefulness of 3 dimensional volume MR imaging technique for demonstrating the facial nerves and to describe MR findings in facial palsy patients and evaluate the significance of facial nerve enhancement. We reviewed the MR images of facial nerves obtained with 3 dimensional volume imaging technique before and after intravenous administration of Gadopentetate dimeglumine in 13 cases who had facial paralysis and 33 cases who had no facial palsy. And we analyzed the detectability of ananatomical segments of intratemporal facial nerves and facial nerve enhancement. When the 3 dimensional volume MR images of 46 nerves were analyzed subjectively, the nerve courses of 43(93%) of 46 nerves were effectively demonstrated on 3 dimensional volume MR images. Internal acoustic canal portions and geniculate ganglion of facial nerve were well visualized on axial images and tympanic and mastoid segments were well depicted on oblique sagittal images. 10 of 13 patients(77%) were visibly enhanced along at least one segment of the facial nerve with swelling or thickening, and nerves of 8 of normal 33 cases(24%) were enhanced without thickening or swelling. MR findings of facial nerve parelysis is asymmetrical thickening of facial nerve with contrast enhancement. The 3 dimensional volume MR imaging technique should be a useful study for the evaluation of intratemporal facial nerve disease.

  1. Conformal house

    Ryttov, Thomas Aaby; Sannino, Francesco

    2010-01-01

    fixed point. As a consistency check we recover the previously investigated bounds of the conformal windows when restricting to a single matter representation. The earlier conformal windows can be imagined to be part now of the new conformal house. We predict the nonperturbative anomalous dimensions at...... the infrared fixed points. We further investigate the effects of adding mass terms to the condensates on the conformal house chiral dynamics and construct the simplest instanton induced effective Lagrangian terms...

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

    Objective: To explore the pulmonary function, DVH and radiation pneumonitis after three-dimensional conformal radiation treatment of III phase non-small-cell lung cancer. Methods: 71 patients (male 52, female 19, median age 63, KPS≥80) were evaluated by pulmonary function tests before radiotherapy and in M1 and M3 after radiotherapy respectively. After 3 months of follow-up time, it reviewed the appearance and grade of radiation pneumonitis. Then V20, V30 and MLD were worked out from dose volume histogram. Results: All patients completed radiotherapy, and total dose was 66-70 Gy. FVC (L), FEV1 (L) and CLCO were (2.58±0.65) L, (1.85±0.58) L and (15.15±4.65)ml/(min) before radio- therapy, with(2.96±0.76) L, (2.13±0.65) L and (14.71±3.92) ml/(min) in M1 after radiotherapy, with (2.65±0.61) L, (1.92±0.52) L and (13.15±3.71)ml/(min)in M3 after radiotherapy. The accidence of radiation pneumonitis was 30%, moderate and severe radiation pneumonitis was 7%. With V20, V30 and MLD increasing, the grade of radiation pneumonitis was increasing. V20, V30 and MLD were related to the change in CLCO value among before, M1 and M3 after radiotherapy, and the correlation coefficient was more than 0.2. Conclusions: There is a relationship in the pulmonary fiction, DVH and radiation pneumonitis surely. The change in CLCO value between before radiotherapy and M1 after radiotherapy could predict the radiation pneumonitis. V20, V30 and MLD are not only correlated to radiation pneumonitis evidently but the change in FEV1 and CLCO after radiotherapy. (authors)

  3. The role of Cobalt-60 source in Intensity Modulated Radiation Therapy: From modeling finite sources to treatment planning and conformal dose delivery

    Dhanesar, Sandeep Kaur

    Cobalt-60 (Co-60) units played an integral role in radiation therapy from the mid-1950s to the 1970s. Although they continue to be used to treat cancer in some parts of the world, their role has been significantly reduced due to the invention of medical linear accelerators. A number of groups have indicated a strong potential for Co-60 units in modern radiation therapy. The Medical Physics group at the Cancer Center of the Southeastern Ontario and Queen's University has shown the feasibility of Intensity Modulated Radiation Therapy (IMRT) via simple conformal treatment planning and dose delivery using a Co-60 unit. In this thesis, initial Co-60 tomotherapy planning investigations on simple uniform phantoms are extended to actual clinical cases based on patient CT data. The planning is based on radiation dose data from a clinical Co-60 unit fitted with a multileaf collimator (MLC) and modeled in the EGSnrc Monte Carlo system. An in house treatment planning program is used to calculate IMRT dose distributions. Conformal delivery in a single slice on a uniform phantom based on sequentially delivered pencil beams is verified by Gafchromic film. Volumetric dose distributions for Co-60 serial tomotherapy are then generated for typical clinical sites that had been treated at our clinic by conventional 6MV IMRT using Varian Eclipse treatment plans. The Co-60 treatment plans are compared with the clinical IMRT plans using conventional matrices such as dose volume histograms (DVH). Dose delivery based on simultaneously opened MLC leaves is also explored and a novel MLC segmentation method is proposed. In order to increase efficiency of dose calculations, a novel convolution based fluence model for treatment planning is also proposed. The ion chamber measurements showed that the Monte Carlo modeling of the beam data under the MIMiC MLC is accurate. The film measurements from the uniform phantom irradiations confirm that IMRT plans from our in-house treatment planning system

  4. Factors related to late GI and GU complications in conformal and conventional radiation treatment of cancer of the prostate

    Purpose: To assess the factors that predict for late GI and GU morbidity in radiation treatment of the prostate. Materials and Methods: Six hundred sixteen consecutive prostate cancer patients treated between 1985 and 1994 with conformal or conventional techniques were included in the analysis. All patients had at least 3 months followup (median 26 months) and received at least 65 Gy. Late GI morbidity was rectal bleeding (requiring more than 2 procedures) or proctitis. Late GU morbidity was cystitis or stricture. Univariate analysis compared the differences in the incidence of RTOG-EORTC grade 3 and 4 late morbidity by age (<60 versus ≥ 60 years), peracute side effects ≥ grade 1 (during treatment), subacute side effects ≥ grade 1 (0 to 90 days after treatment), irradiated volume parameters, and dose. Multivariate proportional hazards analysis includes these same variables in a model of time to complication. Multivariate logistic regression was used to analyze incidence of peracute and subacute GI and GU side effects by GI and GU comorbidities, performance status, pretreatment procedures (biopsy, TURP, etc.), age, treatment volume parameters, and peracute responses. Results: Peracute GI and GU side effects were noted in 441 and 442 patients, respectively. Subacute GI and GU side effects were noted in 34 and 54 patients, respectively. Subacute GI side effects were highly correlated with subacute GU side effects (p<0.00001). Late morbidities were not correlated with peracute side effects but were correlated with subacute side effects (both GI and GU). Thirteen of the 616 patients expressed grade 3 or 4 GI injuries 3 to 32 months after the end of treatment, with a mean of 13 months. The 6 GU morbidities occurred significantly later (9 - 52 months) with a mean of 33 months. Central axis dose and age less than 60 years were the only independent variables significantly related to the incidence of late GI morbidity on multivariate analysis. Subacute and peracute

  5. Differential Cross Section Kinematics for 3-dimensional Transport Codes

    Norbury, John W.; Dick, Frank

    2008-01-01

    In support of the development of 3-dimensional transport codes, this paper derives the relevant relativistic particle kinematic theory. Formulas are given for invariant, spectral and angular distributions in both the lab (spacecraft) and center of momentum frames, for collisions involving 2, 3 and n - body final states.

  6. Controlled teleportation of a 3-dimensional bipartite quantum state

    Cao, Hai-Jing; Chen, Zhong-Hua; Song, He-Shan

    2008-07-01

    A controlled teleportation scheme of an unknown 3-dimensional (3D) two-particle quantum state is proposed, where a 3D Bell state and 3D GHZ state function as the quantum channel. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional bipartite quantum state.

  7. Controlled teleportation of a 3-dimensional bipartite quantum state

    Cao Haijing; Chen Zhonghua [Physics Department, Shanghai University of Electric Power, Shanghai 201300 (China); Song Heshan [Physics Department, Dalian University of Technology, Dalian 116024 (China)], E-mail: 2007000084@shiep.edu.cn

    2008-07-15

    A controlled teleportation scheme of an unknown 3-dimensional (3D) two-particle quantum state is proposed, where a 3D Bell state and 3D GHZ state function as the quantum channel. This teleportation scheme can be directly generalized to teleport an unknown d-dimensional bipartite quantum state.

  8. 2 and 3-dimensional Hamiltonians with Shape Invariance Symmetry

    Jafarizadeh, M. A.; Panahi-Talemi, H.; Faizi, E.

    2000-01-01

    Via a special dimensional reduction, that is, Fourier transforming over one of the coordinates of Casimir operator of su(2) Lie algebra and 4-oscillator Hamiltonian, we have obtained 2 and 3 dimensional Hamiltonian with shape invariance symmetry. Using this symmetry we have obtained their eigenspectrum. In the mean time we show equivalence of shape invariance symmetry and Lie algebraic symmetry of these Hamiltonians.

  9. Whole breast and excision cavity radiotherapy plan comparison: Conformal radiotherapy with sequential boost versus intensity-modulated radiation therapy with a simultaneously integrated boost

    A comparative study was conducted comparing the difference between (1) conformal radiotherapy (CRT) to the whole breast with sequential boost excision cavity plans and (2) intensity-modulated radiation therapy (IMRT) to the whole breast with simultaneously integrated boost to the excision cavity. The computed tomography (CT) data sets of 25 breast cancer patients were used and the results analysed to determine if either planning method produced superior plans. CT data sets from 25 past breast cancer patients were planned using (1) CRT prescribed to 50 Gy in 25 fractions (Fx) to the whole-breast planning target volume (PTV) and 10 Gy in 5Fx to the excision cavity and (2) IMRT prescribed to 60 Gy in 25Fx, with 60 Gy delivered to the excision cavity PTV and 50 Gy delivered to the whole-breast PTV, treated simultaneously. In total, 50 plans were created, with each plan evaluated by PTV coverage using conformity indices, plan maximum dose, lung dose, and heart maximum dose for patients with left-side lesions. CRT plans delivered the lowest plan maximum doses in 56% of cases (average CRT = 6314.34 cGy, IMRT = 6371.52 cGy). They also delivered the lowest mean lung dose in 68% of cases (average CRT = 1206.64 cGy, IMRT = 1288.37 cGy) and V20 in 88% of cases (average CRT = 20.03%, IMRT = 21.73%) and V30 doses in 92% of cases (average CRT = 16.82%, IMRT = 17.97%). IMRT created more conformal plans, using both conformity index and conformation number, in every instance, and lower heart maximum doses in 78.6% of cases (average CRT = 5295.26 cGy, IMRT = 5209.87 cGy). IMRT plans produced superior dose conformity and shorter treatment duration, but a slightly higher planning maximum and increased lung doses. IMRT plans are also faster to treat on a daily basis, with shorter fractionation

  10. Initial experience with intensity-modulated conformal radiation therapy for treatment of the head and neck region

    Purpose: The efficacy of a conventional, noninvasive fixation technique in combination with a commercially available system for conformal radiotherapy by intensity modulation of the treatment beam has been studied. Methods and Materials: A slice-by-slice arc-rotation approach was used to deliver a conformal dose to the target and patient fixation was performed by means of thermoplastic casts. Eleven patients have been treated, of which 9 were for tumors of the head and neck region and 2 were for intracranial lesions. A procedure for target localization and verification of patient positioning suitable for this particular treatment technique has been developed based on the superposition of digitized portals with plots generated from the treatment-planning system. A dosimetric verification of the treatment procedure was performed with an anthropomorphic phantom: both absolute dose measurements (alanine and thermoluminescent detectors) and relative dose distribution measurements (film dosimetry) have been applied. The dose delivered outside the target has also been investigated. Results: The dose verification with the anthropomorphic phantom yielded a ratio between measured and predicted dose values of 1.0 for different treatment schedules and the calculated dose distribution agreed with the measured dose distribution. Day-to-day variations in patient setup of 0.3 cm (translations) and 2.0 deg. (rotations) were considered acceptable for this particular patient population, whereas the verification protocol allowed detection of 0.1 cm translational errors and 1.0 rotational errors. Conclusions: The noninvasive fixation technique in combination with an adapted verification protocol proved to be acceptable for conformal treatment of the head and neck region. Dose measurements, in turn, confirmed the predicted dose values to the target and organs at risk within uncertainty. Daily monitoring becomes mandatory if an accuracy superior to 0.1 cm and 1.0 deg. is required for

  11. 3-Dimensional reconstruction of fluorescent structures in tardigrades

    Franz BRÜMMER

    2007-09-01

    Full Text Available Tardigrades are microscopic animals, thus brightfield microscopy is a well established method for tardigrade observation. Modern techniques in functional genetics like fluorescence in situ hybridisation or fluorescently labelled expression markers demand high resolution fluorescence microscopy. Nevertheless tardigrades are still considered to be difficult objects for fluorescence techniques as they are covered by an opaque and diffracting cuticle. We show a modern technique of structured light illumination that enables us to acquire thin optical sections and consequently to reconstruct 3-dimensional structures in tardigrades with a high spatial resolution in all 3 dimensions. This technique is evaluated on taxonomically valuable internal as well as external structures of eutardigrades: the bucco-pharyngeal apparatus and the claws. The 3-dimensional reconstructions allow the measurement of distances in all 3 dimensions.

  12. Acute toxicity in comprehensive head and neck radiation for nasopharynx and paranasal sinus cancers: cohort comparison of 3D conformal proton therapy and intensity modulated radiation therapy

    To evaluate acute toxicity endpoints in a cohort of patients receiving head and neck radiation with proton therapy or intensity modulated radiation therapy (IMRT). Forty patients received comprehensive head and neck radiation including bilateral cervical nodal radiation, given with or without chemotherapy, for tumors of the nasopharynx, nasal cavity or paranasal sinuses, any T stage, N0-2. Fourteen received comprehensive treatment with proton therapy, and 26 were treated with IMRT, either comprehensively or matched to proton therapy delivered to the primary tumor site. Toxicity endpoints assessed included g-tube dependence at the completion of radiation and at 3 months after radiation, opioid pain medication requirement compared to pretreatment normalized as equivalent morphine dose (EMD) at completion of treatment, and at 1 and 3 months after radiation. In a multivariable model including confounding variables of concurrent chemotherapy and involved nodal disease, comprehensive head and neck radiation therapy using proton therapy was associated with a lower opioid pain requirement at the completion of radiation and a lower rate of gastrostomy tube dependence by the completion of radiation therapy and at 3 months after radiation compared to IMRT. Proton therapy was associated with statistically significant lower mean doses to the oral cavity, esophagus, larynx, and parotid glands. In subgroup analysis of 32 patients receiving concurrent chemotherapy, there was a statistically significant correlation with a greater opioid pain medication requirement at the completion of radiation and both increasing mean dose to the oral cavity and to the esophagus. Proton therapy was associated with significantly reduced radiation dose to assessed non-target normal tissues and a reduced rate of gastrostomy tube dependence and opioid pain medication requirements. This warrants further evaluation in larger studies, ideally with patient-reported toxicity outcomes and quality of life

  13. Catalytic carbon deposition on 3-dimensional carbon fibre supports

    Thornton, Matthew James

    2005-01-01

    Catalytic carbon deposition reactions, using methane, ethane or synthetic natural gas (1.8 vol. % propane, 6.7 vol. % ethane and balance methane) as the carbon-containing gas feedstock with or without the addition of hydrogen, have been investigated over nickel, cobalt and iron catalysts supported on 3-dimensional carbon fibre supports, using both a horizontal tube furnace and an isothermal, isobaric induction furnace. The transition metal catalysts were prepared by impregnating 3-dimens...

  14. Anti-de Sitter 3-dimensional Gravity with Torsion

    Blagojevic, M; Vasilic, M.

    2004-01-01

    Using the canonical formalism, we study the asymptotic symmetries of the topological 3-dimensional gravity with torsion. In the anti-de Sitter sector, the symmetries are realized by two independent Virasoro algebras with classical central charges. In the simple case of the teleparallel vacuum geometry, the central charges are equal to each other and have the same value as in general relativity, while in the general Riemann-Cartan geometry, they become different.

  15. The 3-Dimensional Core Model DYN3D

    Mittag, Siegfried; Rohde, Ulrich; Grundmann, Ulrich

    2010-01-01

    Analyzing the safety margins in transients and accidents of nuclear reactors 3-dimensional models of the core were used to avoid conservative assumptions needed for point kinetics or 1-dimensional models. Therefore the 3D code DYN3D has been developed for the analysis of reactivity initiated accidents (RIA) in thermal nuclear reactors. The power distributions are calculated with the help of nodal expansion methods (NEM) for hexagonal and Cartesian geometry. The fuel rod model and the thermohy...

  16. GLOBAL STABILITY IN TIME-DELAYED 3-DIMENSIONAL RICHARDS MODEL

    2010-01-01

    We obtain the global attractivity and global asymptotical stability of positive equilibria to a 3-dimensional Richards model with delays. Our results do not depend on the size-asymmetry parameter which measures the degree of the curvature of size-growth among individuals over the entire growth curve, and the shape parameter which affects the shape of model curve. Lastly, we gave a numerical simulation to verify the feasibility of our main results.

  17. Circuit-Switched Gossiping in the 3-Dimensional Torus Networks

    Delmas, Olivier; Pérennes, Stéphane

    1996-01-01

    In this paper we describe, in the case of short messages, an efficient gossiping algorithm for 3-dimensional torus networks (wrap-around or toroidal meshes) that uses synchronous circuit-switched routing. The algorithm is based on a recursive decomposition of a torus. The algorithm requires an optimal number of rounds and a quasi-optimal number of intermediate switch settings to gossip in an $7^i \\times 7^i \\times 7^i$ torus.

  18. Decay vertex reconstruction and 3-dimensional lifetime determination at BESⅢ

    XU Min; HE Kang-Lin; ZHANG Zi-Ping; WANG Yi-Fang; BIAN Jian-Ming; CAO Guo-Fu; CAO Xue-Xiang; CHEN Shen-Jian; DENG Zi-Yan; FU Cheng-Dong; GAO Yuan-Ning; HAN Lei; NAN Shao-Qing; HE Miao; HU Ji-Feng; HU Xiao-Wei; HUANG Bin; HUANG Xing-Tao; JIA Lu-Kui; JI Xiao-Sin; LI Hai-Bo; LI Wei-Dong; LIANG Yu-Wie; LIU Chun-Xiu; LIU Huai-Min; LIU Ying; LIU Yong; LUO Tao; L(U) Qi-Wen; MA Qiu-Mei; MA Xiang; MAO Ya-Jun; MAO Ze-Pu; MO Xiao-Hu; NING Fei-Peng; PING Rong-Gang; QIU Jin-Fa; SONG Wen-Bo; SUN Sheng-Sen; SUN Xiao-Dong; SUN Yong-Zhao; TIAN Hao-Lai; WANG Ji-Ke; WANG Liang-Liang; WEN Shuo-Pin; WU Ling-Hui; WU Zhi; XIE Yu-Guang; YAN Jie; YAN Liang; YAO Jian; YUAN Chang-Zheng; YUAN Ye; ZHANG Chang-Chun; ZHANG Jian-Yong; ZHANG Lei; ZHANG Xue-Yao; ZHANG Yao; ZHENG Yang-Heng; ZHU Yong-Sheng; ZOU Jia-Heng

    2009-01-01

    This paper focuses mainly on the vertex reconstruction of resonance particles with a relatively long lifetime such as KSO, A, as well as on lifetime measurements using a 3-dimensional fit. The kinematic constraints between the production and decay vertices and the decay vertex fitting algorithm based on the least squares method are both presented. Reconstruction efficiencies including experimental resolutions are discussed. The results and systematic errors are calculated based on a Monte Carlo simulation.

  19. Invasive 3-Dimensional Organotypic Neoplasia from Multiple Normal Human Epithelia

    Ridky, Todd W.; Chow, Jennifer M.; Wong, David J.; Khavari, Paul A

    2010-01-01

    Refined cancer models are required to assess the burgeoning number of potential targets for cancer therapeutics within a rapid and clinically relevant context. Here we utilize tumor-associated genetic pathways to transform primary human epithelial cells from epidermis, oropharynx, esophagus, and cervix into genetically defined tumors within a human 3-dimensional (3-D) tissue environment incorporating cell-populated stroma and intact basement membrane. These engineered organotypic tissues reca...

  20. Temporal, 3-dimensional, cellular anatomy of corneal wound tissue.

    Jester, J V; Petroll, W M; Barry, P. A.; Cavanagh, H D

    1995-01-01

    We have evaluated temporally the 3-dimensional cellular anatomy of corneal wound tissue in the rabbit eye using in vivo tandem scanning confocal microscopy. In vivo microscopic studies showed that corneal fibroblast migrated into the wound as an interconnected cellular meshwork with long, thin, randomly oriented cell processes. Interconnection of fibroblasts was further confirmed by localisation of monoclonal antibodies to connexin 43 which demonstrated prominent staining of putative gap junc...

  1. LWR core safety analysis with Areva's 3-dimensional methods

    The quality of the safety analysis strongly affects the confidence in the operational safety of a reactor. To ensure the highest quality, it is essential that the methodology consists of appropriate analysis tools and an extensive validation base. Sophisticated 3-dimensional core models ensure that all physical effects relevant for safety are treated and the results are reliable and conservative. The validation base includes measurement campaigns in test facilities and comparisons of the predictions of steady state and transient measured data gathered from plants during many years of operation. Thus, the core models achieve reliable and comprehensive results for a wide range of applications. As an example an overview of the application experience as well as the validation base of AREVA's 3-dimensional codes is given. The importance and necessity of the comprehensive 3-dimensional methodology is illustrated with examples of a BWR and PWR safety analysis. For BWR transient application the analysis of regional power oscillations is considered and regarding the PWR safety analysis an example referring to fast enthalpy rise and the maximum fuel temperature caused by a rod ejection accident is shown. (orig.)

  2. An evaluation of three dimensional conformal radiation therapy versus intensity modulated radiation therapy in radical chemoradiation of esophageal cancer: A dosimetric study

    Soumik Ghosh; Rakesh Kapoor; Rajesh Gupta; Divya Khosla; Rakesh Kochhar; Oinam, Arun S.; Reena Sharma; Sharma, Suresh C.

    2012-01-01

    Aims: To evaluate the feasibility whether intensity-modulated radiotherapy (IMRT) can be used to reduce doses to normal thoracic structures than three-dimensional conformal radiotherapy (3DCRT) in treating esophageal cancer and to compare normal tissue complication probability (NTCP) for lung between two treatment plans. Materials and Methods: A prospective study was carried out from 2009 to 2011, in which 15 inoperable patients of esophageal cancer who were suitable for radical chemoradiatio...

  3. Workers’ Conformism

    Nikolay Ivantchev

    2013-10-01

    Full Text Available Conformism was studied among 46 workers with different kinds of occupations by means of two modified scales measuring conformity by Santor, Messervey, and Kusumakar (2000 – scale for perceived peer pressure and scale for conformism in antisocial situations. The hypothesis of the study that workers’ conformism is expressed in a medium degree was confirmed partly. More than a half of the workers conform in a medium degree for taking risk, and for the use of alcohol and drugs, and for sexual relationships. More than a half of the respondents conform in a small degree for anti-social activities (like a theft. The workers were more inclined to conform for risk taking (10.9%, then – for the use of alcohol, drugs and for sexual relationships (8.7%, and in the lowest degree – for anti-social activities (6.5%. The workers who were inclined for the use of alcohol and drugs tended also to conform for anti-social activities.

  4. Influence of bellyboard on the volume and dose of small bowel in three-dimensional conformal radiation therapy of post-operative Stage II + III rectum cancer

    Objective: To prospectively assess the effect of bellyboard on volume and dose of small bowel in post-operative stage II + III rectum cancer patient treated with three-dimensional conformal radio- therapy. Methods: Nine patients with rectum cancer after radical operation were examined by sim-CT scan. Two sets of images were taken for the whole pelvis with or without bellyboard. A three-beam treatment plan of three-dimensional conformal radiation therapy was made by the XioCMS treatment planning system. The max dose, the mean dose and the dose on V5, V10, V15, V20, V25, V30, V35, V40, V45, V50, V55 were evaluated in the plan of two positions. Results: Of the two sets of plans, the mean dose of the plan with bellyboard was lower than without bellyboard (1749.4 cGy vs 2124.8 cGy, P=0.023). And the high-dose volume of the plan with bellyboard was smaller than without bellyboard (V50: 51.4 cm3 vs 57.7 cm3, P 0.319). However, the low dose volume was signicantly larger than that in the plan with bellyboard(V5: 376.3 cm3 vs 230.1 cm3, P =0.001). And the mean dose(3557.0 cGy vs 4036.1 cGy, P=0.001)and V15-V50 of the bladder were significantly reduced by the bellyboard. Conclusion: The use of bellyboard signicantly reducess the mean dose in small bowel and bladder, and increases the low-dose volume of small bowel for post-operative stage II + III rectum cancer patient when treated with three-dimensional conformal radiotherapy. (authors)

  5. A phase II trial of accelerated hypofractionated three-dimensional conformal radiation therapy in locally advanced non-small cell lung cancer

    Purpose: The aim of this study is to evaluate the safety and efficacy of accelerated hypofractionated radiotherapy (HypoRT) combined with sequential chemotherapy in locally advanced non-small cell lung cancer (NSCLC). Materials and methods: A total of 34 patients with stage III NSCLC were enrolled. All patients received accelerated HypoRT (initially 50 Gy/20 fractions, then a fraction dose of 3 Gy) using three-dimensional conformal radiation therapy (3D-CRT), omitting elective nodal irradiation (ENI), to a total dose of 65-68 Gy. All patients received two cycles of induction chemotherapy; 1-2 cycles of consolidation chemotherapy were given to 31 patients. The primary outcome measure was a profile of radiation toxicity. The secondary endpoints included overall survival (OS), progression-free survival (PFS), locoregional PFS (LR-PFS) and the pattern of initial failure. Results: Radiation toxicity was minimal. The median and 3-year OS, PFS were 19.0 months, 32.1%; 10.0 months, 29.8%, respectively. The 1-, 2-, and 3-year LR-PFS were 69.6%, 60.9% and 60.9%, respectively. No patient experienced isolated elective nodal failure as the first site of failure. Conclusion: This study suggests that accelerated HypoRT using 3D-CRT omitting ENI can be used in combination with sequential chemotherapy in locally advanced NSCLC.

  6. Adjuvant treatment in patients at high risk of recurrence of thymoma: efficacy and safety of a three-dimensional conformal radiation therapy regimen

    Perri, Francesco; Pisconti, Salvatore; Conson, Manuel; Pacelli, Roberto; Della Vittoria Scarpati, Giuseppina; Gnoni, Antonio; D’Aniello, Carmine; Cavaliere, Carla; Licchetta, Antonella; Cella, Laura; Giuliano, Mario; Schiavone, Concetta; Falivene, Sara; Di Lorenzo, Giuseppe; Buonerba, Carlo; Ravo, Vincenzo; Muto, Paolo

    2015-01-01

    Background The clinical benefits of postoperative radiation therapy (PORT) for patients with thymoma are still controversial. In the absence of defined guidelines, prognostic factors such as stage, status of surgical margins, and histology are often considered to guide the choice of adjuvant treatment (radiotherapy and/or chemotherapy). In this study, we describe our single-institution experience of three-dimensional conformal PORT administered as adjuvant treatment to patients with thymoma. Methods Twenty-two consecutive thymoma patients (eleven male and eleven female) with a median age of 52 years and treated at our institution by PORT were analyzed. The patients were considered at high risk of recurrence, having at least one of the following features: stage IIB or III, involved resection margins, or thymic carcinoma histology. Three-dimensional conformal PORT with a median total dose on clinical target volume of 50 (range 44–60) Gy was delivered to the tumor bed by 6–20 MV X-ray of the linear accelerator. Follow-up after radiotherapy was done by computed tomography scan every 6 months for 2 years and yearly thereafter. Results Two of the 22 patients developed local recurrence and four developed distant metastases. Median overall survival was 100 months, and the 3-year and 5-year survival rates were 83% and 74%, respectively. Median disease-free survival was 90 months, and the 5-year recurrence rate was 32%. On univariate analysis, pathologic stage III and presence of positive surgical margins had a significant impact on patient prognosis. Radiation toxicity was mild in most patients and no severe toxicity was registered. Conclusion Adjuvant radiotherapy achieved good local control and showed an acceptable toxicity profile in patients with high-risk thymoma. PMID:26089683

  7. Variation in the Definition of Clinical Target Volumes for Pelvic Nodal Conformal Radiation Therapy for Prostate Cancer

    Purpose: We conducted a comparative study of clinical target volume (CTV) definition of pelvic lymph nodes by multiple genitourinary (GU) radiation oncologists looking at the levels of discrepancies amongst this group. Methods and Materials: Pelvic computed tomography (CT) scans from 2 men were distributed to 14 Radiation Therapy Oncology Group GU radiation oncologists with instructions to define CTVs for the iliac and presacral lymph nodes. The CT data with contours were then returned for analysis. In addition, a questionnaire was completed that described the physicians' method for target volume definition. Results: Significant variation in the definition of the iliac and presacral CTVs was seen among the physicians. The minimum, maximum, mean (SD) iliac volumes (mL) were 81.8, 876.6, 337.6 ± 203 for case 1 and 60.3, 627.7, 251.8 ± 159.3 for case 2. The volume of 100% agreement was 30.6 and 17.4 for case 1 and 2 and the volume of the union of all contours was 1,012.0 and 807.4 for case 1 and 2, respectively. The overall agreement was judged to be moderate in both cases (kappa = 0.53 (p < 0.0001) and kappa = 0.48 (p < 0.0001). There was no volume of 100% agreement for either of the two presacral volumes. These variations were confirmed in the responses to the associated questionnaire. Conclusions: Significant disagreement exists in the definition of the CTV for pelvic nodal radiation therapy among GU radiation oncology specialists. A consensus needs to be developed so as to accurately assess the merit and safety of such treatment.

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

    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 V18 Gy), stomach (mean and V20 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 V18 Gy), liver (mean dose), total bowel (V20 Gy and mean dose), and small bowel (V15 Gy absolute volume ratio) compared with all the photon plans and PS PT. The dosimetric advantage of PT points to the possibility of treating tumor bed and comprehensive nodal areas while providing a more tolerable treatment course that could be used for dose escalation and combining with radiosensitizing chemotherapy

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

    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

  10. SU-E-J-86: Functional Conformal Planning for Stereotactic Body Radiation Therapy with CT-Pulmonary Ventilation Imaging

    Purpose: To evaluate the functional planning using CT-pulmonary ventilation imaging for conformal SBRT. Methods: The CT-pulmonary ventilation image was generated using the Jacobian metric in the in-house program with the NiftyReg software package. Using the ventilation image, the normal lung was split into three lung regions for functionality (high, moderate and low). The anatomical plan (AP) and functional plan (FP) were made for ten lung SBRT patients. For the AP, the beam angles were optimized with the dose-volume constraints for the normal lung sparing and the PTV coverage. For the FP, the gantry angles were also optimized with the additional constraint for high functional lung. The MLC aperture shapes were adjusted to the PTV with the additional 5 mm margin. The dosimetric parameters for PTV, the functional volumes, spinal cord and so on were compared in both plans. Results: Compared to the AP, the FP showed better dose sparing for high- and moderate-functional lungs with similar PTV coverage while not taking care of the low functional lung (High:−12.9±9.26% Moderate: −2.0±7.09%, Low: +4.1±12.2%). For the other normal organs, the FP and AP showed similar dose sparing in the eight patients. However, the FP showed that the maximum doses for spinal cord were increased with the significant increment of 16.4Gy and 21.0Gy in other two patients, respectively. Because the beam direction optimizer chose the unexpected directions passing through the spinal cord. Conclusion: Even the functional conformal SBRT can selectively reduce high- and moderatefunctional lung while keeping the PTV coverage. However, it would be careful that the optimizer would choose unexpected beam angles and the dose sparing for the other normal organs can be worse. Therefore, the planner needs to control the dose-volume constraints and also limit the beam angles in order to achieve the expected dose sparing and coverage

  11. SU-E-J-86: Functional Conformal Planning for Stereotactic Body Radiation Therapy with CT-Pulmonary Ventilation Imaging

    Kurosawa, T; Moriya, S; Sato, M [Komazawa University, Setagaya, Tokyo (Japan); Tachibana, H [National Cancer Center Hospital East, Kashiwa, Chiba (Japan)

    2015-06-15

    Purpose: To evaluate the functional planning using CT-pulmonary ventilation imaging for conformal SBRT. Methods: The CT-pulmonary ventilation image was generated using the Jacobian metric in the in-house program with the NiftyReg software package. Using the ventilation image, the normal lung was split into three lung regions for functionality (high, moderate and low). The anatomical plan (AP) and functional plan (FP) were made for ten lung SBRT patients. For the AP, the beam angles were optimized with the dose-volume constraints for the normal lung sparing and the PTV coverage. For the FP, the gantry angles were also optimized with the additional constraint for high functional lung. The MLC aperture shapes were adjusted to the PTV with the additional 5 mm margin. The dosimetric parameters for PTV, the functional volumes, spinal cord and so on were compared in both plans. Results: Compared to the AP, the FP showed better dose sparing for high- and moderate-functional lungs with similar PTV coverage while not taking care of the low functional lung (High:−12.9±9.26% Moderate: −2.0±7.09%, Low: +4.1±12.2%). For the other normal organs, the FP and AP showed similar dose sparing in the eight patients. However, the FP showed that the maximum doses for spinal cord were increased with the significant increment of 16.4Gy and 21.0Gy in other two patients, respectively. Because the beam direction optimizer chose the unexpected directions passing through the spinal cord. Conclusion: Even the functional conformal SBRT can selectively reduce high- and moderatefunctional lung while keeping the PTV coverage. However, it would be careful that the optimizer would choose unexpected beam angles and the dose sparing for the other normal organs can be worse. Therefore, the planner needs to control the dose-volume constraints and also limit the beam angles in order to achieve the expected dose sparing and coverage.

  12. Proton Arc Reduces Range Uncertainty Effects and Improves Conformality Compared With Photon Volumetric Modulated Arc Therapy in Stereotactic Body Radiation Therapy for Non-Small Cell Lung Cancer

    Seco, Joao, E-mail: jseco@partners.org [Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States); Gu, Guan; Marcelos, Tiago; Kooy, Hanne; Willers, Henning [Francis H. Burr Proton Therapy Center, Department of Radiation Oncology, Massachusetts General Hospital, Boston, Massachusetts (United States)

    2013-09-01

    Purpose: To describe, in a setting of non-small cell lung cancer (NSCLC), the theoretical dosimetric advantages of proton arc stereotactic body radiation therapy (SBRT) in which the beam penumbra of a rotating beam is used to reduce the impact of range uncertainties. Methods and Materials: Thirteen patients with early-stage NSCLC treated with proton SBRT underwent repeat planning with photon volumetric modulated arc therapy (Photon-VMAT) and an in-house-developed arc planning approach for both proton passive scattering (Passive-Arc) and intensity modulated proton therapy (IMPT-Arc). An arc was mimicked with a series of beams placed at 10° increments. Tumor and organ at risk doses were compared in the context of high- and low-dose regions, represented by volumes receiving >50% and <50% of the prescription dose, respectively. Results: In the high-dose region, conformality index values are 2.56, 1.91, 1.31, and 1.74, and homogeneity index values are 1.29, 1.22, 1.52, and 1.18, respectively, for 3 proton passive scattered beams, Passive-Arc, IMPT-Arc, and Photon-VMAT. Therefore, proton arc leads to a 30% reduction in the 95% isodose line volume to 3-beam proton plan, sparing surrounding organs, such as lung and chest wall. For chest wall, V30 is reduced from 21 cm{sup 3} (3 proton beams) to 11.5 cm{sup 3}, 12.9 cm{sup 3}, and 8.63 cm{sup 3} (P=.005) for Passive-Arc, IMPT-Arc, and Photon-VMAT, respectively. In the low-dose region, the mean lung dose and V20 of the ipsilateral lung are 5.01 Gy(relative biological effectiveness [RBE]), 4.38 Gy(RBE), 4.91 Gy(RBE), and 5.99 Gy(RBE) and 9.5%, 7.5%, 9.0%, and 10.0%, respectively, for 3-beam, Passive-Arc, IMPT-Arc, and Photon-VMAT, respectively. Conclusions: Stereotactic body radiation therapy with proton arc and Photon-VMAT generate significantly more conformal high-dose volumes than standard proton SBRT, without loss of coverage of the tumor and with significant sparing of nearby organs, such as chest wall. In addition

  13. Radiation-induced esophageal injury in three-dimensional conformal radiotherapy for non small cell lung cancer

    Objective: To evaluate the clinical factors and treatment parameters related to the acute and late esophageal toxicities in non-small cell lung cancer (NSCLC) treated with three-dimensional conformal radio- therapy(3DCRT). Methods: From August 2000 to December 2002, 87 such patients were reviewed retrospectively with clinical factors and treatment parameters in relation to the acute and late esophageal toxicities. Logistic regression method was used to test their relativities. Results: According to the RTOG criteria, acute esophageal toxicity was observed in 38 patients (43.6%), with 24 in grade I, 8 grade II, 5 grade III and 1 grade IV, while late toxicity was observed in 9 patients (10.3%), with 1 in grade II, 2 grade III and 3 grade IV. The average minimal, maximal and mean esophagus absorbed doses were 405 cGy, 6792 cGy and 3557 cGy, respectively. Chemotherapy, percentage of esophageal volume absorbing dose >50 Gy (V50), V60 and tumor location were significantly correlated with acute esophageal toxicity, as the maximal dose to the esophagus and esophageal normal tissue complication probability were with late esophageal toxicity. Multilogistic regression analysis showed that chemotherapy (OR=3.532), V50 (OR=1.809), V60 (OR=0.940) were the independent factors for acute esophageal toxicity. Acute and late esophageal toxicities had no significant impact on survival. Conclusions: Chemotherapy, V50 and V60 are significantly associated with the acute esophageal toxicity in NSCLC patients treated with 3DCRT. These factors should be given special consideration when planning the treatment for centrally located tumor. (authors)

  14. Analysis of Intensity-Modulated Radiation Therapy (IMRT, Proton and 3D Conformal Radiotherapy (3D-CRT for Reducing Perioperative Cardiopulmonary Complications in Esophageal Cancer Patients

    Ted C. Ling

    2014-12-01

    Full Text Available Background. While neoadjuvant concurrent chemoradiotherapy has improved outcomes for esophageal cancer patients, surgical complication rates remain high. The most frequent perioperative complications after trimodality therapy were cardiopulmonary in nature. The radiation modality utilized can be a strong mitigating factor of perioperative complications given the location of the esophagus and its proximity to the heart and lungs. The purpose of this study is to make a dosimetric comparison of Intensity-Modulated Radiation Therapy (IMRT, proton and 3D conformal radiotherapy (3D-CRT with regard to reducing perioperative cardiopulmonary complications in esophageal cancer patients. Materials. Ten patients with esophageal cancer treated between 2010 and 2013 were evaluated in this study. All patients were simulated with contrast-enhanced CT imaging. Separate treatment plans using proton radiotherapy, IMRT, and 3D-CRT modalities were created for each patient. Dose-volume histograms were calculated and analyzed to compare plans between the three modalities. The organs at risk (OAR being evaluated in this study are the heart, lungs, and spinal cord. To determine statistical significance, ANOVA and two-tailed paired t-tests were performed for all data parameters. Results. The proton plans showed decreased dose to various volumes of the heart and lungs in comparison to both the IMRT and 3D-CRT plans. There was no difference between the IMRT and 3D-CRT plans in dose delivered to the lung or heart. This finding was seen consistently across the parameters analyzed in this study. Conclusions. In patients receiving radiation therapy for esophageal cancer, proton plans are technically feasible while achieving adequate coverage with lower doses delivered to the lungs and cardiac structures. This may result in decreased cardiopulmonary toxicity and less morbidity to esophageal cancer patients.

  15. Analysis of Intensity-Modulated Radiation Therapy (IMRT), Proton and 3D Conformal Radiotherapy (3D-CRT) for Reducing Perioperative Cardiopulmonary Complications in Esophageal Cancer Patients

    Ling, Ted C.; Slater, Jerry M.; Nookala, Prashanth; Mifflin, Rachel; Grove, Roger; Ly, Anh M.; Patyal, Baldev; Slater, Jerry D.; Yang, Gary Y., E-mail: gyang@llu.edu [Department of Radiation Medicine, Loma Linda University Medical Center, 11234 Anderson Street, A875, Loma Linda, CA 92354 (United States)

    2014-12-05

    Background. While neoadjuvant concurrent chemoradiotherapy has improved outcomes for esophageal cancer patients, surgical complication rates remain high. The most frequent perioperative complications after trimodality therapy were cardiopulmonary in nature. The radiation modality utilized can be a strong mitigating factor of perioperative complications given the location of the esophagus and its proximity to the heart and lungs. The purpose of this study is to make a dosimetric comparison of Intensity-Modulated Radiation Therapy (IMRT), proton and 3D conformal radiotherapy (3D-CRT) with regard to reducing perioperative cardiopulmonary complications in esophageal cancer patients. Materials. Ten patients with esophageal cancer treated between 2010 and 2013 were evaluated in this study. All patients were simulated with contrast-enhanced CT imaging. Separate treatment plans using proton radiotherapy, IMRT, and 3D-CRT modalities were created for each patient. Dose-volume histograms were calculated and analyzed to compare plans between the three modalities. The organs at risk (OAR) being evaluated in this study are the heart, lungs, and spinal cord. To determine statistical significance, ANOVA and two-tailed paired t-tests were performed for all data parameters. Results. The proton plans showed decreased dose to various volumes of the heart and lungs in comparison to both the IMRT and 3D-CRT plans. There was no difference between the IMRT and 3D-CRT plans in dose delivered to the lung or heart. This finding was seen consistently across the parameters analyzed in this study. Conclusions. In patients receiving radiation therapy for esophageal cancer, proton plans are technically feasible while achieving adequate coverage with lower doses delivered to the lungs and cardiac structures. This may result in decreased cardiopulmonary toxicity and less morbidity to esophageal cancer patients.

  16. The impact of contrast CT scan on contouring of gross tumor volume of lung cancer in three-dimensional conformal radiation therapy

    Objective: To study the impact of contrast CT scan on contouring of gross tumor volume (GTV) of lung cancer in three-dimensional conformal radiation therapy (3-DCRT). Methods: Seven patients with pathological proven lung lesions close to mediastinum or with invasion of hilum had contrast(C+ ) and non-contrast (C-) CT scans at the radiotherapeutic position. Three radiation oncologists with similar-seniority contoured the GTV independently on both C+ (3copies) and C-(3copies) images, and then together on another copy of C+ image (standard, GTVco). The treatment planning based on GTVco was carried out and optimized with AcQSim plan. The reference dose point was normalized to the isocenter in PTV and prescription dose was 60 Gy. After the GTVs contoured by the three radiation oncologists on C+ and C-images were fused with GTVco, the ratios of these GTVs on C+, C- images (totally 6 copies) for each patient, the longest three dimensions of GTVs, the relative PTV volume covered by 90% isodose curve (V90) and the minimum doses within PTV (Dmin) to the GTVco were calculated, and so were the coefficients of variation (CV)of these ratios. T-test was used for detecting the difference of all parameters. Results: The mean ratio of GTV on the C+ and C- images to standard GTVco were 1.04 ± 0.16, 1.25 ± 0.52, respectively. The CV of GTV, V90, Dmin on the C+ image was significantly smaller than those on C- images (P<0.01, P<0.05, P<0.05). Conclusion: It is more accurate and consistent in contouring the GTV on contrast CT for lesion situated close to mediastinum or with invasion of hilum. (authors)

  17. Long-term androgen deprivation increases Grade 2 and higher late morbidity in prostate cancer patients treated with three-dimensional conformal radiation therapy

    Purpose: To determine whether the use of androgen deprivation (AD) increases late morbidity when combined with high-dose three-dimensional conformal radiation therapy (3D-CRT). Methods and materials: Between May 1989 and November 1998, 1,204 patients were treated for prostate cancer with 3D-CRT to a median dose of 74 Gy. Patients were evaluated every 3-6 months. No AD was given to 945 patients, whereas 140 and 119 patients, respectively, received short-term AD (STAD; ≤6 months) and long-term AD (LTAD; > 6 months). Radiation morbidity was graded according to the Fox Chase modification of the Late Effects Normal Tissue Task Force late morbidity scale. Covariates in the multivariate analysis (MVA) included age, history of diabetes mellitus, prostate-specific antigen (PSA) level, Gleason score, T category, RT field size, total RT dose, use of rectal shielding, and AD status (no AD vs. STAD vs. LTAD). Results: The only independent predictor for Grade 2 or higher genitourinary (GU) morbidity in the MVA was the use of AD (p = 0.0065). The 5-year risk of Grade 2 or higher GU morbidity was 8% for no AD, 8% for STAD, and 14% for LTAD (p = 0.02). Independent predictors of Grade 2 or higher gastrointestinal (GI) morbidity in the MVA were the use of AD (p = 0.0079), higher total radiation dose (p < 0.0001), the lack of a rectal shield (p = 0.0003), and older age (p = 0.0009). The 5-year actuarial risk of Grade 2 or higher GI morbidity was 17% for no AD vs. 18% for STAD and 26% for LTAD (p = 0.017). Conclusions: The use of LTAD seems to significantly increase the risk of both GU and GI morbidity for patients treated with 3D-CRT

  18. The rush to judgment: does the evidence support the enthusiasm over three-dimensional conformal radiation therapy and dose escalation in the treatment of prostate cancer?

    Purpose: To discuss the assumptions behind and current clinical evidence on three-dimensional conformal radiation therapy (3D-CRT) and dose escalation in the treatment of prostate cancer. Methods: We first define 3D-CRT in comparison to standard radiation therapy and discuss the assumptions on which the technology of 3D-CRT and dose escalation are based. We then examine the evidence on the benefits and limitations from the current most commonly cited studies on dose-escalation trials to treat prostate cancer. Results: The assumption that 3D-CRT can provide a tighter margin around the tumor area to allow for dose escalation is not yet proven by studies that show continual difficulty in defining the planning treatment volume because of extrinsic and intrinsic difficulties, such as imaging variabilities and patient and organ movement. Current short-term dose-escalation studies on the use of 3D-CRT to treat prostate cancer are limited in their ability to prove that increasing dose improves survival and does not incur potential long-term complications to normal tissue. Conclusion: Although 3D-CRT is a promising technology that many radiation oncologists and clinics are quickly adopting to treat such tumors as prostate cancer, the long-term evidence on the benefits and limitations of this technology is still lacking. Until we have solid long-term evidence on the true clinical potential of this new technology, let us not rush to judgment, but exercise caution, diligence, and thoughtfulness in using this new technology to treat our patients

  19. Methods to achieve conformal therapy and therapeutic perspectives

    The dramatic improvements in diagnostic radiology, Linac technology and computer sciences permit us to perform fully 3-dimensional conformal treatments. Beam's-eye-view (BEV) visualizations offer the possibilities of tailoring the shape of the radiation beams to the shape of the target with wide possibilities of escalating the target dose without increasing the danger of side effects on normal tissues. Dose-volume histograms and radiobiological evaluations are becoming more and more vital for evaluating the performances of conformal treatments. On the other hand, the verification of the treatment both from the geometrical and the dosimetrical point of view becomes very important. To date, non-uniform beams have been shown to be useful for conformal therapy in some situations; techniques for non-uniform dose delivery are under investigation such as dynamic multi-leaves, scanned beams and 'multi-vane' modulation for tomotherapy. We have recently suggested a new technique for 1D non-uniform dose delivery, using a single computer-controlled absorber. This technique (which could be employed also for 2D modulations by using fan beams), permits to obtain a wide range of modulated beams in a relatively simple way, also on Linac which does not have complex options for computer-controlled therapy. Moreover, it could find important 'traditional' applications such as dynamic wedging and tissue-deficit compensation. A review of our experience in the field of 3D conformal therapy and in the use of radiobiogical models will be presented together with experimental results concerning the production of non-uniform beams by our single absorber modulator

  20. Incorporating interactive 3-dimensional graphics in astronomy research papers

    Barnes, David G

    2007-01-01

    Most research data collections created or used by astronomers are intrinsically multi-dimensional. In contrast, all visual representations of data presented within research papers are exclusively 2-dimensional. We present a resolution of this dichotomy that uses a novel technique for embedding 3-dimensional (3-d) visualisations of astronomy data sets in electronic-format research papers. Our technique uses the latest Adobe Portable Document Format extensions together with a new version of the S2PLOT programming library. The 3-d models can be easily rotated and explored by the reader and, in some cases, modified. We demonstrate example applications of this technique including: 3-d figures exhibiting subtle structure in redshift catalogues, colour-magnitude diagrams and halo merger trees; 3-d isosurface and volume renderings of cosmological simulations; and 3-d models of instructional diagrams and instrument designs.

  1. Scientific visualization of 3-dimensional optimized stellarator configurations

    The design techniques and physics analysis of modern stellarator configurations for magnetic fusion research rely heavily on high performance computing and simulation. Stellarators, which are fundamentally 3-dimensional in nature, offer significantly more design flexibility than more symmetric devices such as the tokamak. By varying the outer boundary shape of the plasma, a variety of physics features, such as transport, stability, and heating efficiency can be optimized. Scientific visualization techniques are an important adjunct to this effort as they provide a necessary ergonomic link between the numerical results and the intuition of the human researcher. The authors have developed a variety of visualization techniques for stellarators which both facilitate the design optimization process and allow the physics simulations to be more readily understood

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

    Purpose: To describe the probability of RILD by application of the Lyman-Kutcher-Burman normal-tissue complication (NTCP) model for primary liver carcinoma (PLC) treated with hypofractionated three-dimensional conformal radiotherapy (3D-CRT). Methods and Materials: A total of 109 PLC patients treated by 3D-CRT were followed for RILD. Of these patients, 93 were in liver cirrhosis of Child-Pugh Grade A, and 16 were in Child-Pugh Grade B. The Michigan NTCP model was used to predict the probability of RILD, and then the modified Lyman NTCP model was generated for Child-Pugh A and Child-Pugh B patients by maximum-likelihood analysis. Results: Of all patients, 17 developed RILD in which 8 were of Child-Pugh Grade A, and 9 were of Child-Pugh Grade B. The prediction of RILD by the Michigan model was underestimated for PLC patients. The modified n, m, TD5 (1) were 1.1, 0.28, and 40.5 Gy and 0.7, 0.43, and 23 Gy for patients with Child-Pugh A and B, respectively, which yielded better estimations of RILD probability. The hepatic tolerable doses (TD5) would be MDTNL of 21 Gy and 6 Gy, respectively, for Child-Pugh A and B patients. Conclusions: The Michigan model was probably not fit to predict RILD in PLC patients. A modified Lyman NTCP model for RILD was recommended

  3. Protalign: a 3-dimensional protein alignment assessment tool.

    Meads, D; Hansen, M D; Pang, A

    1999-01-01

    Protein fold recognition (sometimes called threading) is the prediction of a protein's 3-dimensional shape based on its similarity to a protein of known structure. Fold predictions are low resolution; that is, no effort is made to rotate the protein's component amino acid side chains into their correct spatial orientations. The goal is simply to recognize the protein family member that most closely resembles the target sequence of unknown structure and to create a sensible alignment of the target to the known structure (i.e., a structure-sequence alignment). To facilitate this type of structure prediction, we have designed a low resolution molecular graphics tool. ProtAlign introduces the ability to interact with and edit alignments directly in the 3-dimensional structure as well as in the usual 2-dimensional layout. It also contains several functions and features to help the user assess areas within the alignment. ProtAlign implements an open pipe architecture to allow other programs to access its molecular graphics capabilities. In addition, it is capable of "driving" other programs. Because amino acid side chain orientation is not relevant in fold recognition, we represent amino acid residues as abstract shapes or glyphs much like Lego (tm) blocks and we borrow techniques from comparative flow visualization using streamlines to provide clean depictions of the entire protein model. By creating a low resolution representation of protein structure, we are able to at least double the amount of information on the screen. At the same time, we create a view that is not as busy as the corresponding representations using traditional high resolution visualization methods which show detailed atomic structure. This eliminates distracting and possibly misleading visual clutter resulting from the mapping of protein alignment information onto a high resolution display of the known structure. This molecular graphics program is implemented in Open GL to facilitate porting to

  4. Conformal radiotherapy: a glossary

    Most of the concepts and terms related to conformal radiotherapy were produced by English-speaking authors and eventually validated by international groups of experts, whose working language was also English. Therefore, a significant part of this literature is poorly accessible to the French-speaking radiation oncology community. The present paper gathers the 'official' definitions already published in French, along with propositions for the remaining terms which should be submitted to a more formal and representative validation process. (author)

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

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

  6. A prospective dosimetric and clinical comparison of acute hematological toxicities in three-dimensional conformal radiation therapy and intensity modulated radiation therapy with concurrent chemotherapy in carcinoma cervix

    H U Avinash

    2015-01-01

    Full Text Available Background and Objectives: Acute hematological toxicities are an important cause of morbidity in patients receiving concurrent chemoradiation to pelvis in carcinoma cervix. The objective of this study was to evaluate the role of intensity-modulated radiotherapy (IMRT in reducing the dose to the bone marrow as compared with three-dimensional conformal radiotherapy (3DCRT and hence its impact on reducing the acute hematological toxicities. Materials and Methods: Eleven consecutive patients treated with IMRT and 12 patients treated with 3DCRT to the whole pelvis along with concurrent chemotherapy were selected. Bone marrow was delineated. V10 Gy, V20 Gy, V95%, and Dmean of bone marrow were recorded. Weekly blood counts were recorded and graded as per Common Terminology Criteria version 4.0 for all the patients. Results: The dose to the bone marrow V20 Gy was 206.78 ± 57.10 cc (75% and 251.70 ± 40.45 cc (91% for IMRT and 3DCRT, respectively (P = 0.04 and V95% was 23.30 ± 8.34% and 46.76 ± 6.71% for IMRT and 3DCRT, respectively (P = 0.001. The grade of toxicities during each week did not show the difference in either arm. However, the total count and Neutrophil counts during the 2nd week showed statistical significance between IMRT and 3DCRT. Conclusion: IMRT significantly reduces the dose to the bone marrow as compared to 3DCRT. The reduction of the dose did not translate into a decrease in acute hematological toxicities. Concurrent platinum-based chemotherapy is the probable cause for the hematological toxicities.

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

    Purpose/objective: In this study, we evaluated in a serial manner whether radiation dose to the bulb of the penis is predictive of erectile dysfunction, ejaculatory difficulty (EJ), and overall satisfaction with sex life (quality of life) by using serial validated self-administered questionnaires. Methods and materials: Twenty-nine potent men with AJCC Stage II prostate cancer treated with three-dimensional conformal radiation therapy alone to a median dose 72.0 Gy (range: 66.6-79.2 Gy) were evaluated by determining the doses received by the penile bulb. The penile bulb was delineated volumetrically, and the dose-volume histogram was obtained on each patient. Results: The median follow-up time was 35 months (range, 16-43 months). We found that for D30, D45, D60, and D75 (doses to a percent volume of PB: 30%, 45%, 60%, and 75%), higher than the corresponding median dose (defined as high-dose group) correlated with an increased risk of impotence (erectile dysfunction firmness score = 0) (odds ratio [OR] = 7.5, p = 0.02; OR = 7.5, p = 0.02; OR = 8.6, p = 0.008; and OR = 6.9, p = 0.015, respectively). Similarly, for EJD D30, D45, D60, and D75, doses higher than the corresponding median ones correlated with worsening ejaculatory function score (EJ = 0 or 1) (OR = 8, p = 0.013; OR = 8, p 0.013; OR = 9.2, p = 0.015; and OR = 8, p = 0.026, respectively). For quality of life, low (≤median dose) dose groups of patients improve over time, whereas high-dose groups of patients worsen. Conclusions: This study supports the existence of a penile bulb dose-volume relationship underlying the development of radiation-induced erectile dysfunction. Our data may guide the use of inverse treatment planning to maximize the probability of maintaining sexual potency after radiation therapy

  8. Clinical Outcome of Patients Treated With 3D Conformal Radiation Therapy (3D-CRT) for Prostate Cancer on RTOG 9406

    Purpose: Report of clinical cancer control outcomes on Radiation Therapy Oncology Group (RTOG) 9406, a three-dimensional conformal radiation therapy (3D-CRT) dose escalation trial for localized adenocarcinoma of the prostate. Methods and Materials: RTOG 9406 is a Phase I/II multi-institutional dose escalation study of 3D-CRT for men with localized prostate cancer. Patients were registered on five sequential dose levels: 68.4 Gy, 73.8 Gy, 79.2 Gy, 74 Gy, and 78 Gy with 1.8 Gy/day (levels I–III) or 2.0 Gy/day (levels IV and V). Neoadjuvant hormone therapy (NHT) from 2 to 6 months was allowed. Protocol-specific, American Society for Therapeutic Radiation Oncology (ASTRO), and Phoenix biochemical failure definitions are reported. Results: Thirty-four institutions enrolled 1,084 patients and 1,051 patients are analyzable. Median follow-up for levels I, II, III, IV, and V was 11.7, 10.4, 11.8, 10.4, and 9.2 years, respectively. Thirty-six percent of patients received NHT. The 5-year overall survival was 90%, 87%, 88%, 89%, and 88% for dose levels I–V, respectively. The 5-year clinical disease-free survival (excluding protocol prostate-specific antigen definition) for levels I–V is 84%, 78%, 81%, 82%, and 82%, respectively. By ASTRO definition, the 5-year disease-free survivals were 57%, 59%, 52%, 64% and 75% (low risk); 46%, 52%, 54%, 56%, and 63% (intermediate risk); and 50%, 34%, 46%, 34%, and 61% (high risk) for levels I–V, respectively. By the Phoenix definition, the 5-year disease-free survivals were 68%, 73%, 67%, 84%, and 80% (low risk); 70%, 62%, 70%, 74%, and 69% (intermediate risk); and 42%, 62%, 68%, 54%, and 67% (high risk) for levels I–V, respectively. Conclusion: Dose-escalated 3D-CRT yields favorable outcomes for localized prostate cancer. This multi-institutional experience allows comparison to other experiences with modern radiation therapy.

  9. Three-Year Outcomes of a Canadian Multicenter Study of Accelerated Partial Breast Irradiation Using Conformal Radiation Therapy

    Berrang, Tanya S., E-mail: tberrang@bccancer.bc.ca [British Columbia Cancer Agency-Vancouver Island, BC (Canada); University of British Columbia, BC (Canada); Olivotto, Ivo [British Columbia Cancer Agency-Vancouver Island, BC (Canada); University of British Columbia, BC (Canada); Kim, Do-Hoon [Juravinski Cancer Centre, Ontario (Canada); McMaster University, Ontario (Canada); Nichol, Alan [British Columbia Cancer Agency-Vancouver Centre, BC (Canada); University of British Columbia, BC (Canada); Cho, B.C. John [Princess Margaret Hospital, Ontario (Canada); University of Toronto, Ontario (Canada); Mohamed, Islam G. [British Columbia Cancer Agency-Southern Interior, BC (Canada); University of British Columbia, BC (Canada); Parhar, Tarnjit [British Columbia Cancer Agency-Vancouver Centre, BC (Canada); University of British Columbia, BC (Canada); Wright, J.R. [Juravinski Cancer Centre, Ontario (Canada); McMaster University, Ontario (Canada); Truong, Pauline [British Columbia Cancer Agency-Vancouver Island, BC (Canada); University of British Columbia, BC (Canada); Tyldesley, Scott [British Columbia Cancer Agency-Vancouver Centre, BC (Canada); University of British Columbia, BC (Canada); Sussman, Jonathan [Juravinski Cancer Centre, Ontario (Canada); McMaster University, Ontario (Canada); Wai, Elaine [British Columbia Cancer Agency-Vancouver Island, BC (Canada); University of British Columbia, BC (Canada); Whelan, Tim [Juravinski Cancer Centre, Ontario (Canada); McMaster University, Ontario (Canada)

    2011-12-01

    Purpose: To report 3-year toxicity, cosmesis, and efficacy of a multicenter study of external beam, accelerated partial breast irradiation (APBI) for early-stage breast cancer. Methods and Materials: Between March 2005 and August 2006, 127 women aged {>=}40 years with ductal carcinoma in situ or node-negative invasive breast cancer {<=}3 cm in diameter, treated with breast-conserving surgery achieving negative margins, were accrued to a prospective study involving five Canadian cancer centers. Women meeting predefined dose constraints were treated with APBI using 3 to 5 photon beams, delivering 35 to 38.5 Gy in 10 fractions, twice a day, over 1 week. Patients were assessed for treatment-related toxicities, cosmesis, and efficacy before APBI and at specified time points for as long as 3 years after APBI. Results: 104 women had planning computed tomography scans showing visible seromas, met dosimetric constraints, and were treated with APBI to doses of 35 Gy (n = 9), 36 Gy (n = 33), or 38.5 Gy (n = 62). Eighty-seven patients were evaluated with minimum 3-year follow-up after APBI. Radiation dermatitis, breast edema, breast induration, and fatigue decreased from baseline levels or stabilized by the 3-year follow-up. Hypopigmentation, hyperpigmentation, breast pain, and telangiectasia slightly increased from baseline levels. Most toxicities at 3 years were Grade 1. Only 1 patient had a Grade 3 toxicity with telangiectasia in a skin fold inside the 95% isodose. Cosmesis was good to excellent in 86% (89/104) of women at baseline and 82% (70/85) at 3 years. The 3-year disease-free survival was 97%, with only one local recurrence that occurred in a different quadrant away from the treated site and two distant recurrences. Conclusions: At 3 years, toxicity and cosmesis were acceptable, and local control and disease-free survival were excellent, supporting continued accrual to randomized APBI trials.

  10. Adjuvant treatment in patients at high risk of recurrence of thymoma: efficacy and safety of a three-dimensional conformal radiation therapy regimen

    Perri F

    2015-06-01

    Full Text Available Francesco Perri,1 Salvatore Pisconti,1 Manuel Conson,2,3 Roberto Pacelli,2,3 Giuseppina Della Vittoria Scarpati,2 Antonio Gnoni,1 Carmine D’Aniello,1 Carla Cavaliere,1 Antonella Licchetta,1 Laura Cella,2,3 Mario Giuliano,4,5 Concetta Schiavone,7 Sara Falivene,7 Giuseppe Di Lorenzo,4 Carlo Buonerba,6 Vincenzo Ravo,7 Paolo Muto7 1Medical Oncology Unit, POC S Annunziata, Taranto, 2Department of Advanced Biomedical Sciences, University of Naples Federico II, Naples, 3Institute of Biostructures and Bioimaging, National Council of Research, Naples, 4Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy; 5Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, USA; 6Division of Oncology, Centro di riferimento Oncologico di Basilicata, IRCCS Rionero in Vulture, Potenza, 7Department of Radiotherapy, Istituto Nazionale per la Cura dei Tumori-Fondazione G. Pascale. IRCCS di Napoli, Naples, Italy Background: The clinical benefits of postoperative radiation therapy (PORT for patients with thymoma are still controversial. In the absence of defined guidelines, prognostic factors such as stage, status of surgical margins, and histology are often considered to guide the choice of adjuvant treatment (radiotherapy and/or chemotherapy. In this study, we describe our single-institution experience of three-dimensional conformal PORT administered as adjuvant treatment to patients with thymoma. Methods: Twenty-two consecutive thymoma patients (eleven male and eleven female with a median age of 52 years and treated at our institution by PORT were analyzed. The patients were considered at high risk of recurrence, having at least one of the following features: stage IIB or III, involved resection margins, or thymic carcinoma histology. Three-dimensional conformal PORT with a median total dose on clinical target volume of 50 (range 44–60 Gy was delivered to the tumor bed by 6–20 MV X-ray of the linear

  11. Effect of Radiation Therapy Techniques on Outcome in N3-positive IIIB Non-small Cell Lung Cancer Treated with Concurrent Chemoradiotherapy

    Noh, Jae Myoung; KIM, JIN MAN; Ahn, Yong Chan; Pyo, Hongryull; Kim, BoKyong; Oh, Dongryul; Ju, Sang Gyu; Kim, Jin Sung; Shin, Jung Suk; Hong, Chae-Seon; Park, Hyojung; Lee, Eonju

    2015-01-01

    Purpose This study was conducted to evaluate clinical outcomes following definitive concurrent chemoradiotherapy (CCRT) for patients with N3-positive stage IIIB (N3-IIIB) non-small cell lung cancer (NSCLC), with a focus on radiation therapy (RT) techniques. Materials and Methods From May 2010 to November 2012, 77 patients with N3-IIIB NSCLC received definitive CCRT (median, 66 Gy). RT techniques were selected individually based on estimated lung toxicity, with 3-dimensional conformal RT (3D-C...

  12. Combined proton and photon conformal radiation therapy for locally advanced carcinoma of the prostate: preliminary results of a phase I/II study

    Purpose: A study was developed to evaluate the use of combined photons and protons for the treatment of locally advanced carcinoma of the prostate. This report is a preliminary assessment of treatment-related morbidity and tumor response. Methods and Materials: One hundred and six patients in stages T2b (B2), T2c (B2), and T3 (C) were treated with 45 Gy photon-beam irradiation to the pelvis and an additional 30 Cobalt Gray Equivalent (CGE) to the prostate with 250-MeV protons, yielding a total prostate dose of 75 CGE in 40 fractions. Median follow-up time was 20.2 months (range: 10-30 months). Toxicity was scored according to the Radiation Therapy Oncology Group (RTOG) grading system; local control was evaluated by serial digital rectal examination (DRE) and prostate specific antigen (PSA) measurements. Results: Morbidity evaluation was available on 104 patients. The actuarial 2-year rate of Grade 1 or 2 late morbidity was 12% (8% rectal, 4% urinary). No patients demonstrated Grade 3 or 4 late mobidity. Treatment response was evaluated on 100 patients with elevated pretreatment serum PSA levels. The actuarial 2-year rate of PSA normalization was 96%, 97%, and 63% for pretreatment PSAS of > 4-10, > 10-20, and > 20, respectively. The 13 patients with rising PSA demonstrated local recurrence (3 patients), distant metastasis (8 patients), or no evidence of disease except increasing PSA (2 patients). Conclusion: The low incidence of side effects, despite the tumor dose of 75 CGE, demonstrates that conformal protons can deliver higher doses of radiation to target tissues without increasing complications to surrounding normal tissues. The initial tumor response, as assessed by the high actuarial rate of normalization with pretreatment PSA ≤ 20, and the low rate of recurrences within the treatment field (2.8%), are encouraging

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

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

    2013-08-15

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

  14. Three-dimensional conformal radiotherapy (3D-CRT) versus intensity modulated radiation therapy (IMRT) in squamous cell carcinoma of the head and neck: A randomized controlled trial

    Purpose: To compare three-dimensional conformal radiotherapy (3D-CRT) with intensity modulated radiation therapy (IMRT) in curative-intent irradiation of head-neck squamous cell carcinoma (HNSCC). Methods: Previously untreated patients with biopsy-proven squamous carcinoma of oropharynx, larynx, or hypopharynx (T1-3, N0-2b) were randomly assigned using computer-generated permuted-block design to either 3D-CRT or IMRT, with incidence of physician-rated Radiation Therapy Oncology Group (RTOG) grade 2 or worse acute salivary gland toxicity as primary end-point. Results: Between 2005 and 2008, 60 patients randomly allocated to either 3D-CRT (n = 28 patients) or IMRT (n = 32) were included and analyzed on an intention-to-treat basis. The proportion [95% confidence intervals (CI)] of patients with RTOG grade 2 or worse acute salivary gland toxicity was significantly lesser in the IMRT arm [19 of 32 patients (59%, 95% CI: 42–75%)] as compared to 3D-CRT [25 of 28 patients (89%, 95% CI: 72–97%; p = 0.009)]. Late xerostomia and subcutaneous fibrosis were also significantly lesser with IMRT. There was significant recovery of salivary function over time in patients treated with IMRT (p-value for trend = 0.0036). At 3-years, there were no significant differences in loco-regional control or survival between the two arms. Conclusion: IMRT significantly reduces the incidence and severity of xerostomia compared to 3D-CRT in curative-intent irradiation of HNSCC.

  15. Fixed Point Structure for 3 dimensional rigid string

    Zhao, Weidong

    1993-01-01

    We show that the usual fixed point for 3-d rigid string with topological term appears to be a trivial one, consisting of two decoupled conformal field theories. We further argue that by involving an additional term allowed by symmetries and thus generated by RG, the theory appears to exhibit a new fixed point with expected symmetriy. The new fixed point is studied in the weak- and string coupling limit.

  16. PWR core safety analysis with 3-dimensional methods

    Highlights: • An overview of AREVA’s safety analysis codes their coupling is provided. • The validation base and licensing applications of these codes are summarized. • Coupled codes and methods provide improved margins and non-conservative results. • Examples for REA and inadvertent opening of the pressurizer safety valve are given. - Abstract: The main focus of safety analysis is to demonstrate the required safety level of the reactor core. Because of the demanding requirements, the quality of the safety analysis strongly affects the confidence in the operational safety of a reactor. To ensure the highest quality, it is essential that the methodology consists of appropriate analysis tools, an extensive validation base, and last but not least highly educated engineers applying the methodology. The sophisticated 3-dimensional core models applied by AREVA ensure that all physical effects relevant for safety are treated and the results are reliable and conservative. Presently AREVA employs SCIENCE, CASMO/NEMO and CASCADE-3D for pressurized water reactors. These codes are currently being consolidated into the next generation 3D code system ARCADIA®. AREVA continuously extends the validation base, including measurement campaigns in test facilities and comparisons of the predictions of steady state and transient measured data gathered from plants during many years of operation. Thus, the core models provide reliable and comprehensive results for a wide range of applications. For the application of these powerful tools, AREVA is taking benefit of its interdisciplinary know-how and international teamwork. Experienced engineers of different technical backgrounds are working together to ensure an appropriate interpretation of the calculation results, uncertainty analysis, along with continuously maintaining and enhancing the quality of the analysis methodologies. In this paper, an overview of AREVA’s broad application experience as well as the broad validation

  17. SU-E-T-62: Cardiac Toxicity in Dynamic Conformal Arc Therapy, Intensity-Modulated Radiation Therapy and Volumetric Modulated Arc Therapy of Lung Cancers

    Ming, X; Zhang, Y [Tianjin University, Tianjin (China); Yale University, New Haven, CT, US (United States); Feng, Y [Tianjin University, Tianjin (China); Zhou, L [West China Hospital, Sichuan (China); Yale University, New Haven, CT, US (United States); Deng, J [Yale University, New Haven, CT, US (United States)

    2014-06-01

    Purpose: The cardiac toxicity for lung cancer patients, each treated with dynamic conformal arc therapy (DAT), intensity-modulated radiation therapy (IMRT), or volumetric modulated arc therapy (VMAT) is investigated. Methods: 120 lung patients were selected for this study: 25 treated with DAT, 50 with IMRT and 45 with VMAT. For comparison, all plans were generated in the same treatment planning system, normalized such that the 100% isodose lines encompassed 95% of planning target volume. The plan quality was evaluated in terms of homogeneity index (HI) and 95% conformity index (%95 CI) for target dose coverage and mean dose, maximum dose, V{sub 30} Gy as well as V{sub 5} Gy for cardiac toxicity analysis. Results: When all the plans were analyzed, the VMAT plans offered the best target coverage with 95% CI = 0.992 and HI = 1.23. The DAT plans provided the best heart sparing with mean heart dose = 2.3Gy and maximum dose = 11.6Gy, as compared to 5.7 Gy and 31.1 Gy by IMRT as well as 4.6 Gy and 30.9 Gy by VMAT. The mean V30Gy and V5Gy of the heart in the DAT plans were up to 11.7% lower in comparison to the IMRT and VMAT plans. When the tumor volume was considered, the VMAT plans spared up to 70.9% more doses to the heart when the equivalent diameter of the tumor was larger than 4cm. Yet the maximum dose to the heart was reduced the most in the DAT plans with up to 139.8% less than that of the other two plans. Conclusion: Overall, the VMAT plans achieved the best target coverage among the three treatment modalities, and would spare the heart the most for the larger tumors. The DAT plans appeared advantageous in delivering the least maximum dose to the heart as compared to the IMRT and VMAT plans.

  18. Mapping metabolic changes associated with early Radiation Induced Lung Injury post conformal radiotherapy using hyperpolarized 13C-pyruvate Magnetic Resonance Spectroscopic Imaging

    Purpose: Radiation Pneumonitis (RP) limits radiotherapy. Detection of early metabolic changes in the lungs associated with RP may provide an opportunity to adjust treatment before substantial toxicities occur. In this work, regional lactate-to-pyruvate signal ratio (lac/pyr) was quantified in rat lungs and heart following administration of hyperpolarized 13C-pyruvate magnetic resonance imaging (MRI) at day 5, 10, 15 and 25-post conformal radiotherapy. These results were also compared to histology and blood analyses. Methods: The lower right lungs of 12 Sprague Dawley rats were irradiated in 2 fractions with a total dose of 18.5 Gy using a modified micro-CT system. Regional lactate and pyruvate data were acquired from three irradiated and three age-matched healthy rats at each time point on days 5, 10, 15 and 25-post radiotherapy. Arterial blood was collected from each animal prior to the 13C-pyruvate injection and was analyzed for blood lactate concentration and arterial oxygen concentration (paO2). Macrophage count was computed from the histology of all rat lungs. Results: A significant increase in lac/pyr was observed in both right and left lungs of the irradiated cohort compared to the healthy cohort for all time points. No increase in lac/pyr was observed in the hearts of the irradiated cohort compared to the hearts of the healthy cohorts. Blood lactate concentration and paO2 did not show a significant change between the irradiated and the healthy cohorts. Macrophage count in both right and left lungs was elevated for the irradiated cohort compared to the healthy cohort. Conclusions: Metabolic changes associated with RP may be mapped as early as five days post conformal radiotherapy. Over the small sample size in each cohort, elevated macrophage count, consistent with early phase of inflammation was highly correlated to increases in lac/pyr in both the irradiated and unirradiated lungs. Further experiments with larger sample size may improve the confidence of

  19. Patterns of Recurrence Analysis in Newly Diagnosed Glioblastoma Multiforme After Three-Dimensional Conformal Radiation Therapy With Respect to Pre-Radiation Therapy Magnetic Resonance Spectroscopic Findings

    Purpose: To determine whether the combined magnetic resonance imaging (MRI) and magnetic resonance spectroscopy imaging (MRSI) before radiation therapy (RT) is valuable for RT target definition, and to evaluate the feasibility of replacing the current definition of uniform margins by custom-shaped margins based on the information from MRI and MRSI. Methods and Materials: A total of 23 glioblastoma multiforme (GBM) patients underwent MRI and MRSI within 4 weeks after surgery but before the initiation of RT and at 2-month follow-up intervals thereafter. The MRSI data were quantified on the basis of a Choline-to-NAA Index (CNI) as a measure of spectroscopic abnormality. A combined anatomic and metabolic region of interest (MRI/S) consisting of T2-weighted hyperintensity, contrast enhancement (CE), resection cavity, and CNI2 (CNI ≥ 2) based on the pre-RT imaging was compared to the extent of CNI2 and the RT dose distribution. The spatial relationship of the pre-RT MRI/S and the RT dose volume was compared with the extent of CE at each follow-up. Results: Nine patients showed new or increased CE during follow-up, and 14 patients were either stable or had decreased CE. New or increased areas of CE occurred within CNI2 that was covered by 60 Gy in 6 patients and within the CNI2 that was not entirely covered by 60 Gy in 3 patients. New or increased CE resided within the pre-RT MRI/S lesion in 89% (8/9) of the patients with new or increased CE. Conclusion: These data indicate that the definition of RT target volumes according to the combined morphologic and metabolic abnormality may be sufficient for RT targeting

  20. The 3-dimensional construction of the Rae craton, central Canada

    Snyder, David B.; Craven, James A.; Pilkington, Mark; Hillier, Michael J.

    2015-10-01

    Reconstruction of the 3-dimensional tectonic assembly of early continents, first as Archean cratons and then Proterozoic shields, remains poorly understood. In this paper, all readily available geophysical and geochemical data are assembled in a 3-D model with the most accurate bedrock geology in order to understand better the geometry of major structures within the Rae craton of central Canada. Analysis of geophysical observations of gravity and seismic wave speed variations revealed several lithospheric-scale discontinuities in physical properties. Where these discontinuities project upward to correlate with mapped upper crustal geological structures, the discontinuities can be interpreted as shear zones. Radiometric dating of xenoliths provides estimates of rock types and ages at depth beneath sparse kimberlite occurrences. These ages can also be correlated to surface rocks. The 3.6-2.6 Ga Rae craton comprises at least three smaller continental terranes, which "cratonized" during a granitic bloom. Cratonization probably represents final differentiation of early crust into a relatively homogeneous, uniformly thin (35-42 km), tonalite-trondhjemite-granodiorite crust with pyroxenite layers near the Moho. The peak thermotectonic event at 1.86-1.7 Ga was associated with the Hudsonian orogeny that assembled several cratons and lesser continental blocks into the Canadian Shield using a number of southeast-dipping megathrusts. This orogeny metasomatized, mineralized, and recrystallized mantle and lower crustal rocks, apparently making them more conductive by introducing or concentrating sulfides or graphite. Little evidence exists of thin slabs similar to modern oceanic lithosphere in this Precambrian construction history whereas underthrusting and wedging of continental lithosphere is inferred from multiple dipping discontinuities.

  1. Development and Validation of a 3-Dimensional CFB Furnace Model

    Vepsäläinen, Arl; Myöhänen, Karl; Hyppäneni, Timo; Leino, Timo; Tourunen, Antti

    At Foster Wheeler, a three-dimensional CFB furnace model is essential part of knowledge development of CFB furnace process regarding solid mixing, combustion, emission formation and heat transfer. Results of laboratory and pilot scale phenomenon research are utilized in development of sub-models. Analyses of field-test results in industrial-scale CFB boilers including furnace profile measurements are simultaneously carried out with development of 3-dimensional process modeling, which provides a chain of knowledge that is utilized as feedback for phenomenon research. Knowledge gathered by model validation studies and up-to-date parameter databases are utilized in performance prediction and design development of CFB boiler furnaces. This paper reports recent development steps related to modeling of combustion and formation of char and volatiles of various fuel types in CFB conditions. Also a new model for predicting the formation of nitrogen oxides is presented. Validation of mixing and combustion parameters for solids and gases are based on test balances at several large-scale CFB boilers combusting coal, peat and bio-fuels. Field-tests including lateral and vertical furnace profile measurements and characterization of solid materials provides a window for characterization of fuel specific mixing and combustion behavior in CFB furnace at different loads and operation conditions. Measured horizontal gas profiles are projection of balance between fuel mixing and reactions at lower part of furnace and are used together with both lateral temperature profiles at bed and upper parts of furnace for determination of solid mixing and combustion model parameters. Modeling of char and volatile based formation of NO profiles is followed by analysis of oxidizing and reducing regions formed due lower furnace design and mixing characteristics of fuel and combustion airs effecting to formation ofNO furnace profile by reduction and volatile-nitrogen reactions. This paper presents

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

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

  3. Acute gastrointestinal, genitourinary, and dermatological toxicity during dose-escalated 3D-conformal radiation therapy (3DCRT) using an intrarectal balloon for prostate gland localization and immobilization

    Purpose: We determined the acute gastrointestinal (GI), genitourinary (GU), and dermatologic (D) toxicity during dose-escalated three-dimensional conformal radiation therapy (3DCRT). A modified intrarectal balloon (Medrad) was used for prostate gland localization and immobilization. Methods: Forty-six men with clinical category T1c to T3a, and at least one high-risk feature (PSA >10, Gleason ≥7, or MRI evidence of extracapsular extension or seminal vesical invasion) comprised the study cohort. Treatment consisted of hormonal therapy and 4-field 3DCRT using an intrarectal balloon for the initial 15 of 40 treatments. Planning treatment volume dose was 72 Gy (95% normalization). A Mantel-Haenzel Chi-square test compared the distribution of GU, GI, and D symptoms at baseline and at end of treatment (EOT). Results: There was no significant difference between the 2 time points in the proportion of patients with bowel symptoms (p = 0.73), tenesmus (p = 0.27), nocturia (p = 1.00), or GU urgency (p = 0.40). However, there was a significant decrease in GU frequency (70% vs. 50%, p = 0.46) as a result of medical interventions and a significant increase in hemorrhoidal irritation (4% vs. 20%, p = 0.02) and anal cutaneous skin reaction (0% vs. 70%, p < 0.001). By 3 months after EOT compared to baseline, there was no significant difference in the proportion of patients experiencing hemorrhoidal bleeding (4% vs. 8%, p = 0.52), requiring intervention for hemorrhoidal symptoms (7% vs. 5%, p = 0.8), or experiencing persistent anal cutaneous skin reaction (0% vs. 3%, p = 0.31). Conclusion: Dose-escalated 3DCRT using an intrarectal balloon for prostate localization and immobilization was well tolerated. Acute GU, GI, and D symptoms resolved with standard dietary or medical interventions by the EOT or shortly thereafter

  4. Patient outcomes of monotherapy with hypofractionated three-dimensional conformal radiation therapy for stage T2 or T3 non-small cell lung cancer: a retrospective study

    Hypofractionated three-dimensional conformal radiation therapy (3D-CRT) is a treatment option for patients with early-stage non-small cell lung cancer (NSCLC) who are medically unable to tolerate surgery and who are not amenable to treatment with stereotactic body radiotherapy. This study assessed the efficacy and safety of 3D-CRT as a monotherapy in patients with localized stage T2 or T3 NSCLC. This retrospective study consisted of 29 patients (20 males) aged 56–89 years (median, 76 years) with histologically confirmed NSCLC who underwent 3D-CRT between 2005 and 2014. The median duration of patient observation was 17.0 months (range, 1.0–64.0 months). Complete and partial responses occurred in 13.8 and 44.8 % of patients, respectively, and the overall response rate was 58.2 %. Meanwhile, the 1- and 3-year survival rates were 65.8 and 33.8 %, respectively. In T2 NSCLC, the median survival time (MST) was 12 months, and the 1- and 3-year survival rates were 62.4 and 21.4 %, respectively. In T3 NSCLC, the MST was 17 months, and the 1- and 3-year survival rates were 72.9 and 48.6 %, respectively. Severe toxicities (Common Terminology Criteria Grade 3) were not observed. The mean biologically effective dose required to improve local control exceeded 80 Gy (range, 67.2–96.0 Gy). These findings support a role for 3D-CRT as a treatment option for patients who refuse or could not tolerate surgical therapy with early-stage NSCLC. Although this was a small, retrospective study, it may form the basis for future, larger controlled studies on 3D-CRT as a monotherapy for NSCLC

  5. Clinical and dosimetric risk factors of acute radiation esophagitis in non-small cell lung cancer patients treated with three-dimensional conformal radiotherapy

    Objective: To analyze the clinical and dosimetric risk factors for acute radiation esophagitis (ARE) in non-small cell lung cancer (NSCLC) patients treated with three-dimensional conformal radiotherapy (3D-CRT), and to find significant risk factors for clinical therapy. Methods: A total of 102 NSCLC patients treated with 3D-CRT were retrospectively analyzed.ARE was scored according to the Radiation Therapy Oncology Group (RTOG) criteria with grade 2 or worse. Patients were divided into non-concurrent chemoradiotherapy group and concurrent chemoradiotherapy group. The clinical and dosimetric factors associated with grade 2 or worse ARE were analyzed using univariate logistic regression, multivariate logistic analysis and receiver operating characteristic (ROC) curve. Results: There were no grade 4 or 5 ARE observed in the 102 patients. Nineteen developed grade 2, 15 developed grade 3. In non-concurrent chemoradiotherapy group,multivariate analysis showed that V55 was the only risk factor of grade 2/3 ARE. For ROC curve analysis, the cut-off point of V55 was 16.0 while the area under ROC curve was 0.870 (95% CI: 0.782-0.957, P<0.05). In concurrent chemoradiotherapy group, multivariate analysis showed that V35 and chemotherapy regimens during radiotherapy were risk factors of grade 2/3 ARE. The cut-off point of V35 was 23.75 while the area under ROC curve was 0.782 (95% CI: 0.636-0.927, P<0.05). Vinorelbine and cisplatin regimen showed low incidence of ARE contrast with gemcitabine/docetaxel and cisplatin regimens (33.3% and 66.7%). Conclusions: V55 is the only statistically significant risk factor associated with grade 2 or worse ARE for patients who don't accepted concurrent chemotherapy. V35 and chemotherapy regimens during radiotherapy are statistically significant risk factors associated with grade 2 or worse ARE for patients who accept concurrent chemotherapy. Vinorelbine and cisplatin regimen during radiotherapy shows low incidence of ARE. (authors)

  6. Late radiation side effects, cosmetic outcomes and pain in breast cancer patients after breast-conserving surgery and three-dimensional conformal radiotherapy. Risk-modifying factors

    The purpose of this work was to identify parameters influencing the risk of late radiation side effects, fair or poor cosmetic outcomes (COs) and pain in breast cancer patients after breast-conserving therapy (BCT) and three-dimensional conformal radiotherapy (3D-CRT). Between 2006 and 2013, 159 patients were treated at the Hannover Medical School. Physician-rated toxicity according to the LENT-SOMA criteria, CO and pain were assessed by multivariate analysis. LENT-SOMA grade 1-4 toxicity was observed as follows: fibrosis 10.7 %, telangiectasia 1.2 %, arm oedema 8.8 % and breast oedema 5.0 %. In addition, 15.1 % of patients reported moderate or severe breast pain, and 21.4 % complained about moderate or severe pain in the arm or shoulder. In multivariate analysis, axillary clearing (AC) was significantly associated with lymphoedema of the arm [odds ratio (OR) 4.37, p = 0.011, 95 % confidence interval (CI) 1.4-13.58]. Breast oedema was also highly associated with AC (OR 10.59, p = 0.004, 95 % CI 2.1-53.36), a ptosis grade 2/3 or pseudoptosis and a bra size ≥ cup C (OR 5.34, p = 0.029, 95 % CI 1.2-24.12). A ptosis grade 2/3 or pseudoptosis and a bra size ≥ cup C were the parameters significantly associated with an unfavourable CO (OR 3.19, p = 0.019, 95 % CI 1.2-8.4). Concerning chronic breast pain, we found a trend related to the prescribed radiation dose including boost (OR 1.077, p = 0.060, 95 % CI 0.997-1.164). Chronic shoulder or arm pain was statistically significantly associated with lymphoedema of the arm (OR 3.9, p = 0.027, 95 % CI 1.17-13.5). Chronic arm and breast oedema were significantly influenced by the extent of surgery (AC). Ptotic and large breasts were significantly associated with unfavourable COs and chronic breast oedema. Late toxicities exclusive breast pain were not associated with radiotherapy parameters. (orig.)

  7. Prediction of PET/CT to alleviate radiation pneumonitis in patients with non-small cell lung cancer for 3-dimentional conformal radiotherapy

    Objective: To investigate the impact of PET/CT on clinical staging of non-small cell lung cancer (NSCLC), delineation of target volume, and prediction to alleviate radiation pneumonitis (RP) from 3-dimentional conformal radiotherapy (3D-CRT) planning. Methods: From October 2002 to June 2004, 34 patients diagnosed cytologically or pathologically with NSCLC, who were candidates for radical radiotherapy or surgery, received PET/CT scanning. Both images were transmitted into treatment planning system (TPS) workstations respectively and were fused and reconstructed. All patients were staged according to the 1997 World Health Organization (WHO) staging system. The impact of PET/CT on the clinical staging of all the patients was determined. The gross tumor volume (GTV) was delineated on the CT imaging and PET/CTfused imaging respectively. Based on the two images, 3D- CRT planning was made respectively at the TPS workstation with Topslane software, the planning target volumes (PTV) being defined with a 15 mm margin around GTV of primary lumps (PTV1) and 7 mm for involved lymph nodes (PTV2). Evaluating indexes including VPTV (volume of PTV, VPTV = VPTV1 + VPTV2), V20 (percentage of the total lung volume receiving more than 20 Gy), MLD (mean lung dose) , TCP (tumor control probability) , NTCP (normal tissue complication probability) , and Ds (dose to spinal cord) were selected to be paralleled to compare the quality of the two plans and the impact of PET/CT on RP was further analyzed. Results: In 13 of 34 (38.2%) cases, PET/CT information changed the clinical staging, 8 of which were upstaged and 5 downstaged. For 10 of 34 (29.4%) cases, PET/CT results modified their management decisions. Among 16 patients performed by surgery, 14 had consistent PET/CT staging with pathologic staging. The sensitivity of PET/CT was 93.3% and accuracy 87.5%. Difference of indexes including VPTV, V20 and MLD between the two radiation planning was statistically significant, but Ds, TCP and NTCP

  8. 通过适形调强优化的全脑全脊髓照射技术%Optimization of the Craniospinal Radiation Technique by conformal and intensity modulated radiation therapy

    陈剑; 王洪林; 董海泉; 陶莉; 李永春; 朱虹; 李云海; 夏怡

    2013-01-01

      目的探讨一种简便易行、准确性高的全脑全脊髓照射技术。方法12例颅内生殖细胞瘤患者,给予CT模拟定位,采用半野衔接技术和适形调强放射治疗技术结合,制定临床可行的放射治疗计划,并与常规技术对照。结果经适形调强优化后的全脑全脊髓照射技术剂量分布优于常规定位技术,定位时间明显缩短。患者的近期有效率为100%,无一例发生严重急性反应。结论半野技术结合适形调强放射治疗技术治疗颅内生殖细胞瘤,操作方便,定位时间明显缩短,优化了放射治疗剂量分布。临床疗效好,副作用小,值得进一步推广。%Objective To find a easy, accurated craniospinal radiation technique through conformal and intensity modulated radiation therapy. Methods 12 patients with intracranial geminoma were treated by half-beam radiation technique and confromal and intensity modulated radiation therapy after CT scanning for simulated position. The dose distribution was compared with traditional craniospinal radiation technique. Results The dosimetry index of opitmized technique was superior than traditional way, and the positioning time was significantly shorter. The results after treatment showed that completely response(CR):11 cases, partly response(PR):1 case, and the recent clinical benefit rate(CBR):100%. No severe complications was observed. Conclusion This new way is better than the traditional one in several aspects including ease of positioning, reproducibility and dose distribution. The clinical outcome is satisfied with little complications. We recommended its application in more area.

  9. Maintenance of Sorafenib following combined therapy of three-dimensional conformal radiation therapy/intensity-modulated radiation therapy and transcatheter arterial chemoembolization in patients with locally advanced hepatocellular carcinoma: a phase I/II study

    Three-dimensional conformal radiation therapy (3DCRT)/intensity-modulated radiation therapy (IMRT) combined with or without transcatheter arterial chemoembolization (TACE) for locally advanced hepatocellular carcinoma (HCC) has shown favorable outcomes in local control and survival of locally advanced HCC. However, intra-hepatic spreading and metastasis are still the predominant treatment failure patterns. Sorafenib is a multikinase inhibitor with effects against tumor proliferation and angiogenesis. Maintenance Sorafenib would probably prevent or delay the intrahepatic and extrahepatic spread of HCC after radiotherapy, which provides the rationale for the combination of these treatment modalities. Patients with solitary lesion (bigger than 5 cm in diameter) histologically or cytologically confirmed HCC receive TACE (1-3 cycles) plus 3DCRT/IMRT 4-6 weeks later. Maintenance Sorafenib will be administered only for the patients with non-progression disease 4 to 6 weeks after the completion of radiotherapy. The dose will be 400 mg, p.o., twice a day. Sorafenib will be continuously given for 12 months unless intolerable toxicities and/or tumor progression. If no more than 3 patients discontinue Sorafenib treatment who experience dose-limiting toxicity after necessary dose modification and delay and/or radiation-induced liver disease in the first 15 enrolled patients, the study will recruit second fifteen patients for further evaluating safety and efficacy of treatment. Hypothesis of the current study is that Sorafenib as a maintenance therapy after combined therapy of 3DCRT/IMRT and TACE is safe and superior to radiotherapy combined with TACE alone in terms of time to progression (TTP), progression-free survival (PFS) and overall survival (OS) in comparison to historical data. A recent meta-analysis showed TACE in combination with radiotherapy, improved the survival and the tumor response of patients, and was thus more therapeutically beneficial. In this study, local

  10. Maintenance of Sorafenib following combined therapy of three-dimensional conformal radiation therapy/intensity-modulated radiation therapy and transcatheter arterial chemoembolization in patients with locally advanced hepatocellular carcinoma: a phase I/II study

    Chen Zhen

    2010-02-01

    Full Text Available Abstract Background Three-dimensional conformal radiation therapy (3DCRT/intensity-modulated radiation therapy (IMRT combined with or without transcatheter arterial chemoembolization (TACE for locally advanced hepatocellular carcinoma (HCC has shown favorable outcomes in local control and survival of locally advanced HCC. However, intra-hepatic spreading and metastasis are still the predominant treatment failure patterns. Sorafenib is a multikinase inhibitor with effects against tumor proliferation and angiogenesis. Maintenance Sorafenib would probably prevent or delay the intrahepatic and extrahepatic spread of HCC after radiotherapy, which provides the rationale for the combination of these treatment modalities. Methods and design Patients with solitary lesion (bigger than 5 cm in diameter histologically or cytologically confirmed HCC receive TACE (1-3 cycles plus 3DCRT/IMRT 4-6 weeks later. Maintenance Sorafenib will be administered only for the patients with non-progression disease 4 to 6 weeks after the completion of radiotherapy. The dose will be 400 mg, p.o., twice a day. Sorafenib will be continuously given for 12 months unless intolerable toxicities and/or tumor progression. If no more than 3 patients discontinue Sorafenib treatment who experience dose-limiting toxicity after necessary dose modification and delay and/or radiation-induced liver disease in the first 15 enrolled patients, the study will recruit second fifteen patients for further evaluating safety and efficacy of treatment. Hypothesis of the current study is that Sorafenib as a maintenance therapy after combined therapy of 3DCRT/IMRT and TACE is safe and superior to radiotherapy combined with TACE alone in terms of time to progression (TTP, progression-free survival (PFS and overall survival (OS in comparison to historical data. Discussion A recent meta-analysis showed TACE in combination with radiotherapy, improved the survival and the tumor response of patients, and was

  11. SBNCT plan: A 3-dimensional treatment planning system for boron neutron capture therapy

    The need for accurate and comprehensive 3-dimensional treatment planning for boron neutron capture therapy (BNCT) has been debated for the past several years. Although many argue against the need for elaborate and expensive treatment planning programs which mimic conventional radiotherapy planning systems, it is clear that in order to realize significant gains over conventional fractionated radiation therapy, patients must be treated to the edge of normal tissue tolerance. Just how close to this edge is dictated by the uncertainties in dosimetry. Hence the focus of BNCT planning is the determination of dose distribution throughout normal tissue volumes. Although precise geometric manipulation of the epithermal neutron beam is not achievable, the following variables play an important role in BNCT optimization: patient orientation, dose fractionation, number of fields, megawatt-minutes per fraction, use of surface bolus, and use of collimation. Other variables which are not as easily adjustable and would not, therefore, be part of treatment planning optimization, include external patient contour, internal patient heterogeneities, boron compound distributions, and RBE's. The boron neutron capture therapy planning system developed at SUNY Stony Brook (SBNCT-Plan) was designed as an interactive graphic tool to assist the radiation oncologist in generating the optimum plan for a neutron capture treatment

  12. Target localization and treatment verification for intensity modulated conformal radiation therapy of the head and neck region. The AZ-VUB experience

    Purpose: Based on a previous evaluation of a conventional, non-invasive fixation technique in combination with a commercially available system for conformal radiation therapy by means of intensity modulation of the treatment beam some modifications have been proposed with respect to target localization and treatment verification. This paper reports on an on-going study of which some preliminary results are presented and discussed with respect to reproducibility of the treatment set-up and verification of the dose. Methods and Materials: A slice-by-slice arc-rotation approach was used to deliver a conformal dose to the target and patient fixation was performed by means of a thermoplastic cast. In a previous study a procedure for target localization and verification of patient positioning suitable for this particular treatment technique had been developed and verified dosimetrically with an anthropomorphic phantom: Both absolute dose measurements (alanine and thermoluminescent detectors) and relative dose distribution measurements (film dosimetry) have been applied. Two issues needed special attention, be0ng: (a) Increased accuracy in patient set-up and (b) deviations between measured and predicted dose values to organs at risk (OAR) in extreme situations. In a 2nd phase, fiducial markers fixed to customized earmoulds and a bite block have been introduced for target localization and verification of patient set-up on a day-to-day basis. A dosimetric verification by means of TLD and an anthropomorphic phantom has been performed to investigate the possible influence of leakage dose. Results: The dose verification with the anthropomorphic phantom yielded a ratio between measured and predicted dose values of 1.0 for typical cases. However, large deviations (i.e. measured/calculated=2.9) have been observed in cases with extreme dose constraints to the OAR due to a leakage dose of approximately 0.5%. Dosimetric verification showed good agreement with the dose calculation

  13. Conformal Invariance of Black Hole Temperature

    Jacobson, Ted; Kang, Gungwon

    1993-01-01

    It is shown that the surface gravity and temperature of a stationary black hole are invariant under conformal transformations of the metric that are the identity at infinity. More precisely, we find a conformal invariant definition of the surface gravity of a conformal Killing horizon that agrees with the usual definition(s) for a true Killing horizon and is proportional to the temperature as defined by Hawking radiation. This result is reconciled with the intimate relation between the trace ...

  14. Concurrent three dimension conformal radiation therapy and chemotherapy followed by consolidation chemotherapy for locally advanced non-small cell lung cancer

    Objective: To investigate the comprehensive treatment of inoperable locally advanced non-small cell lung cancer (NSCLC), and to compare the efficacy and toxicity of concurrent chemoradiotherapy (CRT group) with those of concurrent chemoradiotherapy followed by consolidation chemotherapy (CCT group). Methods: Ninety patients with inoperable locally advanced NSCLC were randomized into CRT group or CCT group. CRT group was treated with weekly docetaxel and cisplatin based concurrent chemoradiotherapy. CCT group was treated with the same chemoradiotherapy followed by docetaxel and cisplatin based consolidation chemotherapy. For concurrent chemoradiotherapy, the total irradiation dose was 56-66 Gy given in 5-7 weeks, docetaxel 30 mg/m2 and cisplatin 20 mg/m2 were administrated on day 1, 8, 22 and 29 (≤2 hours before radiation fraction 1, 6, 16, and 21 ). For consolidation chemotherapy, docetaxel 75 mg/m2 and cisplatin 100 mg/m2 were given every three weeks to a total of two cycles. Results: For CRT group and CCT group, the response rates were 69% and 76% (P=0.480), respectively. The median progression-free survival time was 12.0 (95% CI 10.1-13.9) months and 14.5 (95% CI 11.8-17.2) months, respectively. The median survival time was 16.0 (95% CI 11.7-20.3)months and 16.0 (95% CI 13.5- 18.5 ) months, respectively. The 1-, 2- and 3-year progression-free survival rates were 56% and 62%, 12% and 24%, and 3% and 11% (P=0.044), respectively. The 1-, 2- and 3-year overall survival rates were 73% and 78%, 31% and 32%, and 20% and 21% (P=0.308), respectively. The difference of toxicity was not significant between the two group (P>0.05). Conclusions: For patients with locally advanced non-small cell lung cancer, concurrent conformal radiotherapy and chemotherapy followed by consolidation chemotherapy can improve the progression-free survival, but have few effects on overall survival and toxicity. Multicenter clinical trial with more patients should be carried out to confirm the

  15. Improvement of Survival Rate for Patients with Hepatocellular Carcinoma Using Transarterial Chemoembolization in Combination with Three-Dimensional Conformal Radiation Therapy: A Meta-Analysis.

    Bai, Houqiao; Gao, Peng; Gao, Hao; Sun, Guangxi; Dong, Chonghai; Han, Jian; Jiang, Guosheng

    2016-01-01

    BACKGROUND Transarterial chemoembolization (TACE) has been used alone or in combination with three-dimensional conformal radiation therapy (3DCRT) for treating hepatocellular carcinoma (HCC). The overall survival rate of HCC patients undergoing both treatments, however, has not been systematically studied. The aim of this meta-analysis-based study was to evaluate the overall efficacy of the combined therapy or monotherapy, thereby providing information for clinical treatment. MATERIAL AND METHODS We searched Google Scholar, PubMed, and Chinese National Knowledge Infrastructure (CNKI) for eligible studies, and a total of 17 case-control studies (including HCC patients treated by TACE plus 3DCRT or TACE alone) were included to perform the meta-analysis. Based on the available data, we assessed the improvements of 1-year, 2-year, and 3-year survival rate for the combination therapy of TACE and 3DCRT or TACE alone. Furthermore, the analysis was also stratified by the tumor response: complete response (CR), partial response (PR), no response (NR) and progressive disease (PD). Statistical analysis was performed using STATA 12 (Stata Statistical Software: Release 12). RESULTS The results show that HCC patients receiving combination therapy have significantly increased overall survival rate when compared to those receiving TACE alone (1-year survival rate: OR=1.95, 95% CI 1.54-2.47, p=7.3×10^-8; 2-year survival rate: OR=1.87, 95% CI 1.49-2.34, p=1.6×10^-7; 3-year survival rate: OR=2.00, 95% CI 1.52-2.64, p=1.8×10^-6). CONCLUSIONS Assessment of tumor response demonstrates that the combination therapy can efficiently increase the tumor response rate (CR+PR: OR=2.29, 95% CI 1.70-3.08, p=1.1×10^-7), with a lower rate of subsequent tumor development (PD: OR=0.25, 95% CI 0.15-0.40, p=5.5×10^-8). PMID:27228411

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

    Purpose: To investigate tumor control following three-dimensional conformal radiation therapy (3D-CRT) of prostate cancer and to identify dose-distribution variables that correlate with local control assessed through posttreatment prostate biopsies. Methods and Material: Data from 132 patients, treated at Memorial Sloan-Kettering Cancer Center (MSKCC), who had a prostate biopsy 2.5 years or more after 3D-CRT for T1c-T3 prostate cancer with prescription doses of 64.8-81 Gy were analyzed. Variables derived from the dose distribution in the PTV included: minimum dose (Dmin), maximum dose (Dmax), mean dose (Dmean), dose to n% of the PTV (Dn), where n = 1%, ..., 99%. The concept of the equivalent uniform dose (EUD) was evaluated for different values of the surviving fraction at 2 Gy (SF2). Four tumor control probability (TCP) models (one phenomenologic model using a logistic function and three Poisson cell kill models) were investigated using two sets of input parameters, one for low and one for high T-stage tumors. Application of both sets to all patients was also investigated. In addition, several tumor-related prognostic variables were examined (including T-stage, Gleason score). Univariate and multivariate logistic regression analyses were performed. The ability of the logistic regression models (univariate and multivariate) to predict the biopsy result correctly was tested by performing cross-validation analyses and evaluating the results in terms of receiver operating characteristic (ROC) curves. Results: In univariate analysis, prescription dose (Dprescr), Dmax, Dmean, dose to n% of the PTV with n of 70% or less correlate with outcome (p 2: EUD correlates significantly with outcome for SF2 of 0.4 or more, but not for lower SF2 values. Using either of the two input parameters sets, all TCP models correlate with outcome (p 2, is limited because the low dose region may not coincide with the tumor location. Instead, for MSKCC prostate cancer patients with their

  17. Acute and Late Toxicity After Dose Escalation to 82 GyE Using Conformal Proton Radiation for Localized Prostate Cancer: Initial Report of American College of Radiology Phase II Study 03-12

    Purpose: Several randomized trials have shown a benefit of dose escalation to 78 to 79 Gy for men treated with external radiation for localized prostate cancer. Single-institution data suggest a benefit with even higher doses. American College of Radiology 03-12 is a Phase II trial testing the safety and efficacy of 82 GyE (Gray equivalent) delivered with conformal proton radiation. Methods and Materials: From 2003–2006, 85 men with localized prostate cancer were accrued to American College of Radiology 03-12. Eighty-four were eligible for analysis. They were treated with conformal proton radiation alone to a total dose of 82 GyE. The study was designed to test whether the rate of 18-month Grade 3+ late toxicity was greater than 10%. Results: The median follow-up was 31.6 months. Regarding treatment-related acute toxicity, there were 39 Grade 1 cases (46%), 19 Grade 2 cases (23%) and 2 Grade 3 cases (2%). Regarding genitourinary/gastrointestinal toxicity, there were 42 Grade 1 cases (50%), 12 Grade 2 cases (14%) and 1 Grade 3 case (1%). Regarding late toxicity, there were 28 Grade 1 cases (33%), 22 Grade 2 cases (26%), 6 Grade 3 cases (7%), and 1 Grade 4 case (1%). The late genitourinary/gastrointestinal rates were the same. The estimated rate of Grade 3+ late toxicity at 18 months was 6.08%. Conclusions: Although not free of late toxicity, 82 GyE at 2 GyE per fraction delivered with conformal proton radiation did not exceed the late morbidity target tested in this trial. There was sufficient morbidity, however, that this may be the maximal dose that can be delivered safely with this technique and fractionation.

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

    Selek, Uğur; Bölükbaşı, Yasemin; Welsh, James W.; Topkan, Erkan

    2014-01-01

    Chemoradiotherapy is the current standard of care in patients with advanced inoperable stage IIIA or IIIB non-small cell lung cancer (NSCLC). Three-dimensional radiotherapy (3DCRT) has been a trusted method for a long time and has well-known drawbacks, most of which could be improved by Intensity Modulated Radiotherapy (IMRT). IMRT is not currently the standard treatment of locally advanced NSCLC, but almost all patients could benefit to a degree in organ at risk sparing, dose coverage confor...

  19. Development of a 3-dimensional CT using an image intensifier

    A prototype of three-dimensional CT (Fluoroscopic CT) has been developed using an image intensifier as a two-dimensional X-ray detector. A patient on a rotating table is projected onto an image intensifier by a cone beam of X-ray from the X-ray tube. A total of 390 projection images covering 180 degrees are acquired in a single scan (13 sec) and stored on a digital frame recorder (512 x 256 x 8-bit x 480). The transverse axial images are reconstructed by using the usual CT reconstruction algorithm, while longitudinal section images such as sagittal, coronal, oblique, and panoramic images are obtained by directly back-projecting the filtered projection image onto the sections. The radiation exposure was measured with an ionization chamber, and the exposure of the present fluoroscopic CT is about 10 to 20 times less than that of conventional X-ray CT. A similar monochromatic X-ray CT system has also been developed using synchrotron radiation. Large area parallel X-rays are obtained from a wiggler beam using a silicon crystal with [311] asymmetric reflection. By taking two images above and below iodine K-absorption edge (33.17 keV), iodine image is obtained. (author)

  20. A 60GHz-Band 3-Dimensional System-in-Package Transmitter Module with Integrated Antenna

    Suematsu, Noriharu; Yoshida, Satoshi; Tanifuji, Shoichi; Kameda, Suguru; Takagi, Tadashi; Tsubouchi, Kazuo

    A low cost, ultra small Radio Frequency (RF) transceiver module with integrated antenna is one of the key technologies for short range millimeter-wave wireless communication. This paper describes a 60GHz-band transmitter module with integrated dipole antenna. The module consists of three pieces of low-cost organic resin substrate. These substrates are vertically stacked by employing Cu ball bonding 3-dimensional (3-D) system-in-package (SiP) technology and the MMIC's are mounted on each organic substrates by using Au-stud bump bonding (SBB) technique. The planer dipole antenna is fabricated on the top of the stacked organic substrate to avoid the influence of the grounding metal on the base substrate. At 63GHz, maximum actual gain of 6.0dBi is obtained for fabricated planar dipole antenna. The measured radiation patterns are agreed with the electro-magnetic (EM) simulated result, therefore the other RF portion of the 3-D front-end module, such as flip chip mounted IC's on the top surface of the module, does not affect the antenna characteristics. The results show the feasibility of millimeter-wave low cost, ultra small antenna integrated module using stacked organic substrates.

  1. Attitudinal Conformity and Anonymity

    Tyson, Herbert; Kaplowitz, Stan

    1977-01-01

    Tested college students for conformity when conditions contributing to conformity were absent. Found that social pressures (responding in public, being surveyed by fellow group members) are necessary to produce conformity. (RL)

  2. Radiation

    The chapter one presents the composition of matter and atomic theory; matter structure; transitions; origin of radiation; radioactivity; nuclear radiation; interactions in decay processes; radiation produced by the interaction of radiation with matter

  3. Various approaches to the modelling of large scale 3-dimensional circulation in the Ocean

    Shaji, C.; Bahulayan, N.; Rao, A.D; Dube, S.K.

    In this paper, the three different approaches to the modelling of large scale 3-dimensional flow in the ocean such as the diagnostic, semi-diagnostic (adaptation) and the prognostic are discussed in detail. Three-dimensional solutions are obtained...

  4. Late radiation side effects, cosmetic outcomes and pain in breast cancer patients after breast-conserving surgery and three-dimensional conformal radiotherapy. Risk-modifying factors

    Hille-Betz, Ursula; Soergel, Philipp; Kundu, Sudip; Klapdor, Ruediger; Hillemanns, Peter [Hannover Medical School, Department of Obstetrics and Gynaecology, Hannover (Germany); Vaske, Bernhard [Hannover Medical School, Institute of Medical Biometry and Informatics, Hannover (Germany); Bremer, Michael; Henkenberens, Christoph [Hannover Medical School, Department of Radiation Oncology and Special Oncology, Hannover (Germany)

    2016-01-15

    The purpose of this work was to identify parameters influencing the risk of late radiation side effects, fair or poor cosmetic outcomes (COs) and pain in breast cancer patients after breast-conserving therapy (BCT) and three-dimensional conformal radiotherapy (3D-CRT). Between 2006 and 2013, 159 patients were treated at the Hannover Medical School. Physician-rated toxicity according to the LENT-SOMA criteria, CO and pain were assessed by multivariate analysis. LENT-SOMA grade 1-4 toxicity was observed as follows: fibrosis 10.7 %, telangiectasia 1.2 %, arm oedema 8.8 % and breast oedema 5.0 %. In addition, 15.1 % of patients reported moderate or severe breast pain, and 21.4 % complained about moderate or severe pain in the arm or shoulder. In multivariate analysis, axillary clearing (AC) was significantly associated with lymphoedema of the arm [odds ratio (OR) 4.37, p = 0.011, 95 % confidence interval (CI) 1.4-13.58]. Breast oedema was also highly associated with AC (OR 10.59, p = 0.004, 95 % CI 2.1-53.36), a ptosis grade 2/3 or pseudoptosis and a bra size ≥ cup C (OR 5.34, p = 0.029, 95 % CI 1.2-24.12). A ptosis grade 2/3 or pseudoptosis and a bra size ≥ cup C were the parameters significantly associated with an unfavourable CO (OR 3.19, p = 0.019, 95 % CI 1.2-8.4). Concerning chronic breast pain, we found a trend related to the prescribed radiation dose including boost (OR 1.077, p = 0.060, 95 % CI 0.997-1.164). Chronic shoulder or arm pain was statistically significantly associated with lymphoedema of the arm (OR 3.9, p = 0.027, 95 % CI 1.17-13.5). Chronic arm and breast oedema were significantly influenced by the extent of surgery (AC). Ptotic and large breasts were significantly associated with unfavourable COs and chronic breast oedema. Late toxicities exclusive breast pain were not associated with radiotherapy parameters. (orig.) [German] Ziel dieser Arbeit war es, Parameter zu identifizieren, die Spaetschaeden nach Radiotherapie, ein unguenstiges

  5. Initial magnetic field configurations for 3-dimensional simulations of astrophysical jets

    Jorgensen, M.; R. Ouyed; Christensen, M.

    2001-01-01

    We solve, and provide analytical expressions, for current-free magnetic configurations in the context of initial setups of 3-dimensional simulations of astrophysical jets involving an accretion disk corona in hydrostatic balance around a central object. These configurations which thread through the accretion disk and its corona preserve the initial hydrostatic state. This work sets stage for future 3-dimensional jet simulations (including disk rotation and mass-load) where launching, accelera...

  6. Observation of a New Magnetic Response in 3-Dimensional Split Ring Resonators under Normal Incidence

    Chiam, S. Y.; Bettiol, A. A.; Bahou, M.; Han, J; Moser, H. O.; Watt, F

    2008-01-01

    So far, research in the field of metamaterials has been carried out largely with arrays of flat, 2-dimensional structures. Here, we report a newly identified magnetic resonance in Split Cylinder Resonators (SCRs), a 3-dimensional version of the Split Ring Resonator (SRR), which were fabricated with the Proton Beam Writing technique. Experimental and numerical results indicate a hitherto unobserved 3-dimensional resonance mode under normal incidence at about 26 THz, when the SCR depth is appro...

  7. Conformal transformations and conformal invariance in gravitation

    Dabrowski, Mariusz P.; Garecki, Janusz; Blaschke, David B.

    2008-01-01

    Conformal transformations are frequently used tools in order to study relations between various theories of gravity and the Einstein relativity. In this paper we discuss the rules of these transformations for geometric quantities as well as for the matter energy-momentum tensor. We show the subtlety of the matter energy-momentum conservation law which refers to the fact that the conformal transformation "creates" an extra matter term composed of the conformal factor which enters the conservat...

  8. Novel Radiobiological Gamma Index for Evaluation of 3-Dimensional Predicted Dose Distribution

    Sumida, Iori, E-mail: sumida@radonc.med.osaka-u.ac.jp [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Yamaguchi, Hajime; Kizaki, Hisao; Aboshi, Keiko; Tsujii, Mari; Yoshikawa, Nobuhiko; Yamada, Yuji [Department of Radiation Oncology, NTT West Osaka Hospital, Osaka (Japan); Suzuki, Osamu; Seo, Yuji [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Isohashi, Fumiaki [Department of Radiation Oncology, NTT West Osaka Hospital, Osaka (Japan); Yoshioka, Yasuo [Department of Radiation Oncology, Osaka University Graduate School of Medicine, Osaka (Japan); Ogawa, Kazuhiko [Department of Radiation Oncology, NTT West Osaka Hospital, Osaka (Japan)

    2015-07-15

    Purpose: To propose a gamma index-based dose evaluation index that integrates the radiobiological parameters of tumor control (TCP) and normal tissue complication probabilities (NTCP). Methods and Materials: Fifteen prostate and head and neck (H&N) cancer patients received intensity modulated radiation therapy. Before treatment, patient-specific quality assurance was conducted via beam-by-beam analysis, and beam-specific dose error distributions were generated. The predicted 3-dimensional (3D) dose distribution was calculated by back-projection of relative dose error distribution per beam. A 3D gamma analysis of different organs (prostate: clinical [CTV] and planned target volumes [PTV], rectum, bladder, femoral heads; H&N: gross tumor volume [GTV], CTV, spinal cord, brain stem, both parotids) was performed using predicted and planned dose distributions under 2%/2 mm tolerance and physical gamma passing rate was calculated. TCP and NTCP values were calculated for voxels with physical gamma indices (PGI) >1. We propose a new radiobiological gamma index (RGI) to quantify the radiobiological effects of TCP and NTCP and calculate radiobiological gamma passing rates. Results: The mean RGI gamma passing rates for prostate cases were significantly different compared with those of PGI (P<.03–.001). The mean RGI gamma passing rates for H&N cases (except for GTV) were significantly different compared with those of PGI (P<.001). Differences in gamma passing rates between PGI and RGI were due to dose differences between the planned and predicted dose distributions. Radiobiological gamma distribution was visualized to identify areas where the dose was radiobiologically important. Conclusions: RGI was proposed to integrate radiobiological effects into PGI. This index would assist physicians and medical physicists not only in physical evaluations of treatment delivery accuracy, but also in clinical evaluations of predicted dose distribution.

  9. Logarithmic Conformal Field Theory Solutions of Two Dimensional Magnetohydrodynamics

    Skoulakis, Spyros; Thomas, Steven

    1998-01-01

    We consider the application of logarithmic conformal field theory in finding solutions to the turbulent phases of 2-dimensional models of magnetohydrodynamics. These arise upon dimensional reduction of standard (infinite conductivity) 3-dimensional magnetohydrodynamics, after taking various simplifying limits. We show that solutions of the corresponding Hopf equations and higher order integrals of motion can be found within the solutions of ordinary turbulence proposed by Flohr, based on the ...

  10. Exposure Risks Among Children Undergoing Radiation Therapy: Considerations in the Era of Image Guided Radiation Therapy.

    Hess, Clayton B; Thompson, Holly M; Benedict, Stanley H; Seibert, J Anthony; Wong, Kenneth; Vaughan, Andrew T; Chen, Allen M

    2016-04-01

    Recent improvements in toxicity profiles of pediatric oncology patients are attributable, in part, to advances in the field of radiation oncology such as intensity modulated radiation (IMRT) and proton therapy (IMPT). While IMRT and IMPT deliver highly conformal dose to targeted volumes, they commonly demand the addition of 2- or 3-dimensional imaging for precise positioning--a technique known as image guided radiation therapy (IGRT). In this manuscript we address strategies to further minimize exposure risk in children by reducing effective IGRT dose. Portal X rays and cone beam computed tomography (CBCT) are commonly used to verify patient position during IGRT and, because their relative radiation exposure is far less than the radiation absorbed from therapeutic treatment beams, their sometimes significant contribution to cumulative risk can be easily overlooked. Optimizing the conformality of IMRT/IMPT while simultaneously ignoring IGRT dose may result in organs at risk being exposed to a greater proportion of radiation from IGRT than from therapeutic beams. Over a treatment course, cumulative central-axis CBCT effective dose can approach or supersede the amount of radiation absorbed from a single treatment fraction, a theoretical increase of 3% to 5% in mutagenic risk. In select scenarios, this may result in the underprediction of acute and late toxicity risk (such as azoospermia, ovarian dysfunction, or increased lifetime mutagenic risk) in radiation-sensitive organs and patients. Although dependent on variables such as patient age, gender, weight, body habitus, anatomic location, and dose-toxicity thresholds, modifying IGRT use and acquisition parameters such as frequency, imaging modality, beam energy, current, voltage, rotational degree, collimation, field size, reconstruction algorithm, and documentation can reduce exposure, avoid unnecessary toxicity, and achieve doses as low as reasonably achievable, promoting a culture and practice of "gentle IGRT

  11. The 3-Dimensional q-Deformed Harmonic Oscillator and Magic Numbers of Alkali Metal Clusters

    Bonatsos, Dennis; Raychev, P P; Roussev, R P; Terziev, P A; Bonatsos, Dennis

    1999-01-01

    Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator with Uq(3) > SOq(3) symmetry are compared to experimental data for alkali metal clusters, as well as to theoretical predictions of jellium models, Woods--Saxon and wine bottle potentials, and to the classification scheme using the 3n+l pseudo quantum number. The 3-dimensional q-deformed harmonic oscillator correctly predicts all experimentally observed magic numbers up to 1500 (which is the expected limit of validity for theories based on the filling of electronic shells), thus indicating that Uq(3), which is a nonlinear extension of the U(3) symmetry of the spherical (3-dimensional isotropic) harmonic oscillator, is a good candidate for being the symmetry of systems of alkali metal clusters.

  12. Alternative conformal quantum mechanics

    Ho, Shih-Hao

    2011-01-01

    We investigate a one dimensional quantum mechanical model, which is invariant under translations and dilations but does not respect the conventional conformal invariance. We describe the possibility of modifying the conventional conformal transformation such that a scale invariant theory is also invariant under this new conformal transformation.

  13. Superspace conformal field theory

    Quella, Thomas [Koeln Univ. (Germany). Inst. fuer Theoretische Physik; Schomerus, Volker [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-07-15

    Conformal sigma models and WZW models on coset superspaces provide important examples of logarithmic conformal field theories. They possess many applications to problems in string and condensed matter theory. We review recent results and developments, including the general construction of WZW models on type I supergroups, the classification of conformal sigma models and their embedding into string theory.

  14. Superspace conformal field theory

    Conformal sigma models and WZW models on coset superspaces provide important examples of logarithmic conformal field theories. They possess many applications to problems in string and condensed matter theory. We review recent results and developments, including the general construction of WZW models on type I supergroups, the classification of conformal sigma models and their embedding into string theory.

  15. A Script for Automated 3-Dimentional Structure Generation and Conformer Search from 2- Dimentional Chemical Drawing

    Ishikawa, Yoshinobu

    2013-01-01

    Building 3-dimensional (3D) molecules is the starting point in molecular modeling. Conformer search and identification of a global energy minimum structure are often performed computationally during spectral analysis of data from NMR, IR, and VCD or during rational drug design through ligand-based, structure-based, and QSAR approaches. I herein report a convenient script that allows for automated building of 3D structures and conformer searching from 2-dimensional (2D) drawing of chemical str...

  16. Conformal and non Conformal Dilaton Gravity

    Alvarez, Enrique; Mart'\\in, C P

    2014-01-01

    The quantum dynamics of the gravitational field non-minimally coupled to an (also dynamical) scalar field is studied in the broken phase. For a particular value of the coupling the system is classically conformal, and can actually be understood as the group averaging of Einstein-Hilbert's action under conformal transformations. Contradicting cherished beliefs, a conformal anomaly is found in the trace of the equations of motion. To one loop order, this anomaly vanishes on shell. Arguments are given supporting the fact that this does not happen to two loop order, where the anomaly is argued to be a real physical effect.

  17. A Fortran program (RELAX3D) to solve the 3 dimensional Poisson (Laplace) equation

    RELAX3D is an efficient, user friendly, interactive FORTRAN program which solves the Poisson (Laplace) equation Λ2=p for a general 3 dimensional geometry consisting of Dirichlet and Neumann boundaries approximated to lie on a regular 3 dimensional mesh. The finite difference equations at these nodes are solved using a successive point-iterative over-relaxation method. A menu of commands, supplemented by HELP facility, controls the dynamic loading of the subroutine describing the problem case, the iterations to converge to a solution, and the contour plotting of any desired slices, etc

  18. Contribution of three-dimensional conformal intensity-modulated radiation therapy for women affected by bulky stage II supradiaphragmatic Hodgkin disease

    Antoni, Delphine; Natarajan-Ame, Shanti; Meyer, Philippe; Niederst, Claudine; Bourahla, Khalil; Noel, Georges

    2013-01-01

    Purpose To analyze the outcome and dose distribution of intensity-modulated radiation therapy (IMRT) by helical tomotherapy in women treated for large supradiaphragmatic Hodgkin’s disease. Material and methods A total of 13 patients received adjuvant radiation at a dose of 30 Gy to the initially involved sites with a boost of 6 Gy to those areas suspected of harboring residual disease on the simulation CT scan. Results With a median follow-up of 23 months, the two-year progression-free surviv...

  19. Dosimetric effect of Elekta Beam Modulator micromultileaf in three-dimensional conformal radiotherapy and intensity-modulated radiotherapy for prostate cancer

    Carosi, Alessandra, E-mail: alessandra.carosi@katamail.com; Ingrosso, Gianluca; Ponti, Elisabetta; Tolu, Barbara; Murgia, Alessandra; Cristino, Daniela di; Santoni, Riccardo

    2014-07-01

    The purpose of this study is to analyze the dosimetric effect of Elekta Beam Modulator in 3-dimensional conformal radiation therapy (3DCRT) and in intensity-modulated radiation therapy (IMRT) for localized prostate cancer. We compared treatment plans developed with 2 different Elekta multileaf collimators (MLC): Beam Modulator micro-MLC (mMLC) (4-mm leaf width at the isocenter) and standard MLC (10-mm leaf width at the isocenter). The comparison was performed for 15 patients with localized prostate cancer in 3DCRT and IMRT delivery; a total of 60 treatment plans were processed. The dose-volume histograms were used to provide the quantitative comparison between plans. In particular, we analyzed differences between rectum and bladder sparing in terms of a set of appropriate Vx (percentage of organ at risk [OAR] volume receiving the x dose) and differences between target conformity and coverage in terms of coverage factor and conformation number. Our analysis demonstrates that in 3DCRT there is an advantage in the use of Elekta Beam Modulator mMLC in terms of organ sparing; in particular, a significant decrease in rectal V{sub 60} and V{sub 50} (p = 0.001) and in bladder V{sub 70} and V{sub 65} (p = 0.007 and 0.002, respectively) was found. Moreover, a better target dose conformity was obtained (p = 0.002). IMRT plans comparison demonstrated no significant differences between the use of the 4 or 10-mm MLCs. Our analysis shows that in 3DCRT the use of the Elekta Beam Modulator mMLC gives a gain in target conformity and in OARs dose sparing whereas in IMRT plans there is no advantage.

  20. Dynamics of large scale 3-dimensional circulation of the Indian Ocean

    Swapna, P.

    One of the main objective of this thesis is to adapt and configure a fully non-linear, primitive equation type, sigma co-ordinate 3-dimensional circulation model for the entire Indian Ocean area which can be run on diagnostic, semi...

  1. Full 3-dimensional digital workflow for multicomponent dental appliances : A proof of concept

    van der Meer, W. Joerd; Vissink, Arjan; Ren, Yijin

    2016-01-01

    BACKGROUND: The authors used a 3-dimensional (3D) printer and a bending robot to produce a multicomponent dental appliance to assess whether 3D digital models of the dentition are applicable for a full digital workflow. METHODS: The authors scanned a volunteer's dentition with an intraoral scanner (

  2. Fast convergence to an invariant measure for non-intersecting 3-dimensional Brownian paths

    Lawler, Gregory F

    2010-01-01

    We consider pairs of 3-dimensional Brownian paths, started at the origin and conditioned to have no intersections after time zero. We show that there exists a unique measure on pairs of paths that is invariant under this conditioning, while improving the previously known rate of convergence to stationarity.

  3. 3-Dimensional Cahn-Hilliard Equation with Concentration Dependent Mobility and Gradient Dependent Potential

    Rui HUANG; Yang CAO

    2011-01-01

    In this paper we investigate the initial boundary value problem of Cahn-Hilliard equation with concentration dependent mobility and gradient dependent potential. By the energy method and the theory of Campanato spaces, we prove the existence and the uniqueness of classical solutions in 3-dimensional space.

  4. Is nonangiogenesis a novel pathway for cancer progression? A study using 3-dimensional tumour reconstructions

    Adighibe, O; Micklem, K; Campo, L; Ferguson, M.; Harris, A; Pozos, R; Gatter, K; Pezzella, F.

    2006-01-01

    The nonangiogenic lung tumour is characterized by neoplastic cells co-opting the pre-existent vasculature and filling the alveoli space. 3-Dimensional reconstruction of the tumour reveals that this particular tumour progresses without neovascularization and there is no major destruction of the lung's architectural integrity.

  5. 3-dimensional orthodontics visualization system with dental study models and orthopantomograms

    Zhang, Hua; Ong, S. H.; Foong, K. W. C.; Dhar, T.

    2005-04-01

    The aim of this study is to develop a system that provides 3-dimensional visualization of orthodontic treatments. Dental plaster models and corresponding orthopantomogram (dental panoramic tomogram) are first digitized and fed into the system. A semi-auto segmentation technique is applied to the plaster models to detect the dental arches, tooth interstices and gum margins, which are used to extract individual crown models. 3-dimensional representation of roots, generated by deforming generic tooth models with orthopantomogram using radial basis functions, is attached to corresponding crowns to enable visualization of complete teeth. An optional algorithm to close the gaps between deformed roots and actual crowns by using multi-quadratic radial basis functions is also presented, which is capable of generating smooth mesh representation of complete 3-dimensional teeth. User interface is carefully designed to achieve a flexible system with as much user friendliness as possible. Manual calibration and correction is possible throughout the data processing steps to compensate occasional misbehaviors of automatic procedures. By allowing the users to move and re-arrange individual teeth (with their roots) on a full dentition, this orthodontic visualization system provides an easy and accurate way of simulation and planning of orthodontic treatment. Its capability of presenting 3-dimensional root information with only study models and orthopantomogram is especially useful for patients who do not undergo CT scanning, which is not a routine procedure in most orthodontic cases.

  6. 3-Dimensional and Interactive Istanbul University Virtual Laboratory Based on Active Learning Methods

    Ince, Elif; Kirbaslar, Fatma Gulay; Yolcu, Ergun; Aslan, Ayse Esra; Kayacan, Zeynep Cigdem; Alkan Olsson, Johanna; Akbasli, Ayse Ceylan; Aytekin, Mesut; Bauer, Thomas; Charalambis, Dimitris; Gunes, Zeliha Ozsoy; Kandemir, Ceyhan; Sari, Umit; Turkoglu, Suleyman; Yaman, Yavuz; Yolcu, Ozgu

    2014-01-01

    The purpose of this study is to develop a 3-dimensional interactive multi-user and multi-admin IUVIRLAB featuring active learning methods and techniques for university students and to introduce the Virtual Laboratory of Istanbul University and to show effects of IUVIRLAB on students' attitudes on communication skills and IUVIRLAB. Although…

  7. Study of new chaotic flows on a family of 3-dimensional systems with quadratic nonlinearities

    Based on a wider systematic search on a family of 3-dimensional systems with quadratic nonlinearities, three new simple chaotic systems were found. One of them has the unusual feature of having a stable equilibrium point, and it is the simplest one of other chaotic flows with this property. The others have some interesting special properties

  8. On Maximal Surfaces in Certain Non-Flat 3-Dimensional Robertson-Walker Spacetimes

    Romero, Alfonso, E-mail: aromero@ugr.es [Universidad de Granada, Departamento de Geometria y Topologia (Spain); Rubio, Rafael M., E-mail: rmrubio@uco.es [Universidad de Cordoba, Departamento de Matematicas, Campus de Rabanales (Spain)

    2012-09-15

    An upper bound for the integral, on a geodesic disc, of the squared length of the gradient of a distinguished function on any maximal surface in certain non-flat 3-dimensional Robertson-Walker spacetimes is obtained. As an application, a new proof of a known Calabi-Bernstein's theorem is given.

  9. Analysis of Intensity-Modulated Radiation Therapy (IMRT), Proton and 3D Conformal Radiotherapy (3D-CRT) for Reducing Perioperative Cardiopulmonary Complications in Esophageal Cancer Patients

    Ling, Ted C.; Jerry M. Slater; Prashanth Nookala; Rachel Mifflin; Roger Grove; Ly, Anh M.; Baldev Patyal; Jerry D. Slater; Yang, Gary Y.

    2014-01-01

    Background. While neoadjuvant concurrent chemoradiotherapy has improved outcomes for esophageal cancer patients, surgical complication rates remain high. The most frequent perioperative complications after trimodality therapy were cardiopulmonary in nature. The radiation modality utilized can be a strong mitigating factor of perioperative complications given the location of the esophagus and its proximity to the heart and lungs. The purpose of this study is to make a dosimetric comparison of ...

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

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

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

    De Wagter, C. [ed.

    1995-12-01

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

  12. Clinical advantage and limitation of the 3-dimensional magnetic resonance imaging of the brain

    The authors discuss practical techniques of 3-dimensional magnetic resonance images. Raw data for 3-dimensional MRI were acquired using a 3D turbo-FLASH sequence. The data were processed in the following three ways; 1) volume rendering of all the raw data, 2) segmentation of the brain from other tissue using other software and the volume rendering of all the raw data, and 3) reconstruction of 2-dimensional image of the arbitrary orientation (oblique-oblique and curvature) using multi-planar reconstruction (MPR). In addition to these basic techniques, a surgical window technique, maximum intensity projection (MIP), and skin marking using fatty acid gel in capsules can provide the following unique images; 1) surface images of the skin, skull and brain, 2) images of the arteries and the main cortical vein superimposed on the brain-surface images, and 3) surgical images simulating craniotomy. The drawbacks of 3-dimensional MRI at present are twofold; 1)it requires mini-computers, which is not always available at every clinical site, and 2) the time necessary for data processing and image reconstruction depends on the performance of the computer, but in any case the segmentation of the brain from other soft tissue is a time-consuming job, one which generally takes several hours. However, it is expected that these present limitations of 3-dimentional MRI are only temporary because fast and high cost-performance computers for this specific purpose (image processing) have recently become available. The authors stress that the most important factor which drives the development of a high cost-performance system for 3-dimensional MRI is the demand from clinicians, who realize the advantages of 3-dimensional MRI. (author)

  13. Analyzing predictors of radiation-induced esophageal toxicity in patients with stage III unresectable non-small cell lung cancer treated with three-dimensional conformal radiotherapy

    Objective: To evaluate clinical and dosimetric predictors of acute and late esophageal toxicity in patients with stage III non-small-cell lung cancer (NSCLC) treated with three-dimensional conformal radio-therapy(3D-CRT). Methods: The authors retrospectively reviewed 56 patients with NSCLC who were treated with 3D-CRT between August 2000 and December 2002. The clinic factors and treatment parameters were collected and coded. Acute and late esophageal toxicities were graded. All factors correlating with acute and late esophageal toxicity were analyzed. Results: 24 patients (42.8%) developed acute esophageal toxicity, 7 patients (12.5%) developed late esophageal toxicity, according to RTOG scores, the acute esophageal toxicities were graded: I-14,II-2, III-25; late esophageal toxicity were graded: I-2, II-1, III-4. Spearman rank correlation coefficients showed that chemotherapy, percentages of esophagus volume receiving >50 Gy(V50 ), the average dose to the esophagus, correlated with acute esophageal toxicity, and the gross tumor volume (GTV), the fraction of radiotherapy were significantly correlated with late esophageal toxicity. Binary Logistic regression analysis showed chemotherapy, esophageal V50, were the independent risk factors of acute esophageal toxicity. Esophageal NTCP and GTV were the independent risk factors of late esophageal toxicity. There were no relation between the survival ratio and acute, late esophageal toxicity. Conclusions: In stage III NSCLC patients treated with 3D-CRT, chemotherapy and esophageal V50 were significantly associated with a risk of acute esophageal toxicity; esophageal NTCP and GTV were the independent risk factors of late esophageal toxicity. (authors)

  14. Proton Beam Therapy Versus Conformal Photon Radiation Therapy for Childhood Craniopharyngioma: Multi-institutional Analysis of Outcomes, Cyst Dynamics, and Toxicity

    Bishop, Andrew J. [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Greenfield, Brad [Department of Radiation Oncology, Baylor College of Medicine, Houston, Texas (United States); Mahajan, Anita [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Paulino, Arnold C. [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Baylor College of Medicine, Houston, Texas (United States); Okcu, M. Fatih [Department of Pediatrics, Texas Children' s Cancer and Hematology Center, Baylor College of Medicine, Houston, Texas (United States); Allen, Pamela K. [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Chintagumpala, Murali [Department of Pediatrics, Texas Children' s Cancer and Hematology Center, Baylor College of Medicine, Houston, Texas (United States); Kahalley, Lisa S. [Section of Psychology, Texas Children' s Cancer and Hematology Center, Baylor College of Medicine, Houston, Texas (United States); McAleer, Mary F.; McGovern, Susan L. [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States); Whitehead, William E. [Department of Neurosurgery, Texas Children' s Cancer and Hematology Center, Baylor College of Medicine, Houston, Texas (United States); Grosshans, David R., E-mail: dgrossha@mdanderson.org [Department of Radiation Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas (United States)

    2014-10-01

    Purpose: We compared proton beam therapy (PBT) with intensity modulated radiation therapy (IMRT) for pediatric craniopharyngioma in terms of disease control, cyst dynamics, and toxicity. Methods and Materials: We reviewed records from 52 children treated with PBT (n=21) or IMRT (n=31) at 2 institutions from 1996-2012. Endpoints were overall survival (OS), disease control, cyst dynamics, and toxicity. Results: At 59.6 months' median follow-up (PBT 33 mo vs IMRT 106 mo; P<.001), the 3-year outcomes were 96% for OS, 95% for nodular failure-free survival and 76% for cystic failure-free survival. Neither OS nor disease control differed between treatment groups (OS P=.742; nodular failure-free survival P=.546; cystic failure-free survival P=.994). During therapy, 40% of patients had cyst growth (20% requiring intervention); immediately after therapy, 17 patients (33%) had cyst growth (transient in 14), more commonly in the IMRT group (42% vs 19% PBT; P=.082); and 27% experienced late cyst growth (32% IMRT, 19% PBT; P=.353), with intervention required in 40%. Toxicity did not differ between groups. On multivariate analysis, cyst growth was related to visual and hypothalamic toxicity (P=.009 and .04, respectively). Patients given radiation as salvage therapy (for recurrence) rather than adjuvant therapy had higher rates of visual and endocrine (P=.017 and .024, respectively) dysfunction. Conclusions: Survival and disease-control outcomes were equivalent for PBT and IMRT. Cyst growth is common, unpredictable, and should be followed during and after therapy, because it contributes to late toxicity. Delaying radiation therapy until recurrence may result in worse visual and endocrine function.

  15. Proton Beam Therapy Versus Conformal Photon Radiation Therapy for Childhood Craniopharyngioma: Multi-institutional Analysis of Outcomes, Cyst Dynamics, and Toxicity

    Purpose: We compared proton beam therapy (PBT) with intensity modulated radiation therapy (IMRT) for pediatric craniopharyngioma in terms of disease control, cyst dynamics, and toxicity. Methods and Materials: We reviewed records from 52 children treated with PBT (n=21) or IMRT (n=31) at 2 institutions from 1996-2012. Endpoints were overall survival (OS), disease control, cyst dynamics, and toxicity. Results: At 59.6 months' median follow-up (PBT 33 mo vs IMRT 106 mo; P<.001), the 3-year outcomes were 96% for OS, 95% for nodular failure-free survival and 76% for cystic failure-free survival. Neither OS nor disease control differed between treatment groups (OS P=.742; nodular failure-free survival P=.546; cystic failure-free survival P=.994). During therapy, 40% of patients had cyst growth (20% requiring intervention); immediately after therapy, 17 patients (33%) had cyst growth (transient in 14), more commonly in the IMRT group (42% vs 19% PBT; P=.082); and 27% experienced late cyst growth (32% IMRT, 19% PBT; P=.353), with intervention required in 40%. Toxicity did not differ between groups. On multivariate analysis, cyst growth was related to visual and hypothalamic toxicity (P=.009 and .04, respectively). Patients given radiation as salvage therapy (for recurrence) rather than adjuvant therapy had higher rates of visual and endocrine (P=.017 and .024, respectively) dysfunction. Conclusions: Survival and disease-control outcomes were equivalent for PBT and IMRT. Cyst growth is common, unpredictable, and should be followed during and after therapy, because it contributes to late toxicity. Delaying radiation therapy until recurrence may result in worse visual and endocrine function

  16. Conformal symmetries of spacetimes

    In this paper, we give a unified and global new approach to the study of the conformal structure of the three classical Riemannian spaces as well as of the six relativistic and non-relativistic spacetimes (Minkowskian, de Sitter, anti-de Sitter, and both Newton-Hooke and Galilean). We obtain general expressions within a Cayley-Klein framework, holding simultaneously for all these nine spaces, whose cycles (including geodesics and circles) are explicitly characterized in a new way. The corresponding cycle-preserving symmetries, which give rise to (Moebius-like) conformal Lie algebras, together with their differential realizations are then deduced without having to resort to solving the conformal Killing equations. We show that each set of three spaces with the same signature type and any curvature have isomorphic conformal algebras; these are related through an apparently new conformal duality. Laplace and wave-type differential equations with conformal algebra symmetry are finally constructed. (author)

  17. Conformal Anomalies in Hydrodynamics

    Eling, Christopher; Theisen, Stefan; Yankielowicz, Shimon

    2013-01-01

    We study the effect of conformal anomalies on the hydrodynamic description of conformal field theories in four spacetime dimensions. We consider equilibrium curved backgrounds characterized by a time-like Killing vector and construct a local low energy effective action that captures the conformal anomalies. Using as a special background the Rindler spacetime we derive a formula for the effect of the anomaly on the hydrodynamic pressure.

  18. Galilean Conformal Electrodynamics

    Bagchi, Arjun; Basu, Rudranil; Mehra, Aditya

    2014-01-01

    Maxwell’s Electrodynamics admits two distinct Galilean limits called the Electric and Magnetic limits. We show that the equations of motion in both these limits are invariant under the Galilean Conformal Algebra in D = 4, thereby exhibiting non-relativistic conformal symmetries. Remarkably, the symmetries are infinite dimensional and thus Galilean Electrodynamics give us the first example of an infinitely extended Galilean Conformal Field Theory in D > 2. We examine details of the theory by l...

  19. Juvenile Delinquency and Conformism

    Patacchini, Eleonora; Zenou, Yves

    2010-01-01

    This paper studies whether conformism behavior affects individual outcomes in crime. We present a social network model of peer effects with ex-ante heterogeneous agents and show how conformism and deterrence affect criminal activities. We then bring the model to the data by using a very detailed dataset of adolescent friendship networks. A novel social network-based empirical strategy allows us to identify peer effects for different types of crimes. We find that conformity plays an important ...

  20. Predictors of High-grade Esophagitis After Definitive Three-dimensional Conformal Therapy, Intensity-modulated Radiation Therapy, or Proton Beam Therapy for Non-small cell Lung Cancer

    Gomez, Daniel R., E-mail: dgomez@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Tucker, Susan L. [Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Martel, Mary K.; Mohan, Radhe; Balter, Peter A. [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lopez Guerra, Jose Luis [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Radiation Oncology, Hospitales Universitarios Virgen del Rocio, Seville (Spain); Liu Hongmei; Komaki, Ritsuko; Cox, James D.; Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-11-15

    Introduction: We analyzed the ability of various patient- and treatment-related factors to predict radiation-induced esophagitis (RE) in patients with non-small cell lung cancer (NSCLC) treated with three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or proton beam therapy (PBT). Methods and Materials: Patients were treated for NSCLC with 3D-CRT, IMRT, or PBT at MD Anderson from 2000 to 2008 and had full dose-volume histogram (DVH) data available. The endpoint was severe (grade {>=}3) RE. The Lyman-Kutcher-Burman (LKB) model was used to analyze RE as a function of the fractional esophageal DVH, with clinical variables included as dose-modifying factors. Results: Overall, 652 patients were included: 405 patients were treated with 3D-CRT, 139 with IMRT, and 108 with PBT; corresponding rates of grade {>=}3 RE were 8%, 28%, and 6%, respectively, with a median time to onset of 42 days (range, 11-93 days). A fit of the fractional DVH LKB model demonstrated that the fractional effective dose was significantly different (P=.046) than 1 (fractional mean dose) indicating that high doses to small volumes are more predictive than mean esophageal dose. The model fit was better for 3D-CRT and PBT than for IMRT. Including receipt of concurrent chemotherapy as a dose-modifying factor significantly improved the LKB model (P=.005), and the model was further improved by including a variable representing treatment with >30 fractions. Examining individual types of chemotherapy agents revealed a trend toward receipt of concurrent taxanes and increased risk of RE (P=.105). Conclusions: Fractional dose (dose rate) and number of fractions (total dose) distinctly affect the risk of severe RE, estimated using the LKB model, and concurrent chemotherapy improves the model fit. This risk of severe RE is underestimated by this model in patients receiving IMRT.

  1. Predictors of High-grade Esophagitis After Definitive Three-dimensional Conformal Therapy, Intensity-modulated Radiation Therapy, or Proton Beam Therapy for Non-small cell Lung Cancer

    Introduction: We analyzed the ability of various patient- and treatment-related factors to predict radiation-induced esophagitis (RE) in patients with non-small cell lung cancer (NSCLC) treated with three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), or proton beam therapy (PBT). Methods and Materials: Patients were treated for NSCLC with 3D-CRT, IMRT, or PBT at MD Anderson from 2000 to 2008 and had full dose-volume histogram (DVH) data available. The endpoint was severe (grade ≥3) RE. The Lyman-Kutcher-Burman (LKB) model was used to analyze RE as a function of the fractional esophageal DVH, with clinical variables included as dose-modifying factors. Results: Overall, 652 patients were included: 405 patients were treated with 3D-CRT, 139 with IMRT, and 108 with PBT; corresponding rates of grade ≥3 RE were 8%, 28%, and 6%, respectively, with a median time to onset of 42 days (range, 11-93 days). A fit of the fractional DVH LKB model demonstrated that the fractional effective dose was significantly different (P=.046) than 1 (fractional mean dose) indicating that high doses to small volumes are more predictive than mean esophageal dose. The model fit was better for 3D-CRT and PBT than for IMRT. Including receipt of concurrent chemotherapy as a dose-modifying factor significantly improved the LKB model (P=.005), and the model was further improved by including a variable representing treatment with >30 fractions. Examining individual types of chemotherapy agents revealed a trend toward receipt of concurrent taxanes and increased risk of RE (P=.105). Conclusions: Fractional dose (dose rate) and number of fractions (total dose) distinctly affect the risk of severe RE, estimated using the LKB model, and concurrent chemotherapy improves the model fit. This risk of severe RE is underestimated by this model in patients receiving IMRT.

  2. Galilean Conformal Electrodynamics

    Bagchi, Arjun; Mehra, Aditya

    2014-01-01

    Maxwell's Electrodynamics admits two distinct Galilean limits called the Electric and Magnetic limits. We show that the equations of motion in both these limits are invariant under the Galilean Conformal Algebra in D=4, thereby exhibiting non-relativistic conformal symmetries. Remarkably, the symmetries are infinite dimensional and thus Galilean Electrodynamics give us the first example of an infinitely extended Galilean Conformal Field Theory in D>2. We examine details of the theory by looking at purely non-relativistic conformal methods and also use input from the limit of the relativistic theory.

  3. Galilean conformal electrodynamics

    Bagchi, Arjun; Basu, Rudranil; Mehra, Aditya

    2014-11-01

    Maxwell's Electrodynamics admits two distinct Galilean limits called the Electric and Magnetic limits. We show that the equations of motion in both these limits are invariant under the Galilean Conformal Algebra in D = 4, thereby exhibiting non-relativistic conformal symmetries. Remarkably, the symmetries are infinite dimensional and thus Galilean Electrodynamics give us the first example of an infinitely extended Galilean Conformal Field Theory in D > 2. We examine details of the theory by looking at purely non-relativistic conformal methods and also use input from the limit of the relativistic theory.

  4. In-vitro investigation of out-of-field cell survival following the delivery of conformal, intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) plans

    The aim of this work is to determine the out-of-field survival of cells irradiated with either the primary field or scattered radiation in the presence and absence of intercellular communication following delivery of conformal, IMRT and VMAT treatment plans. Single beam, conformal, IMRT and VMAT plans were created to deliver 3 Gy to half the area of a T80 flask containing either DU-145 or AGO-1522 cells allowing intercellular communication between the in- and out-of-field cell populations. The same plans were delivered to a similar custom made phantom used to hold two T25 culture flasks, one flask in-field and one out-of-field to allow comparison of cell survival responses when intercellular communication is physically inhibited. Plans were created for the delivery of 8 Gy to the more radio-resistant DU-145 cells only in the presence and absence of intercellular communication. Cell survival was determined by clonogenic assay. In both cell lines, the out-of-field survival was not statistically different between delivery techniques for either cell line or dose. There was however, a statistically significant difference between survival out-of-field when intercellular communication was intact (single T80 culture flask) or inhibited (multiple T25 culture flasks) to in-field for all plans. No statistically significant difference was observed in-field with or without cellular communication to out-of-field for all plans. These data demonstrate out-of-field effects as important determinants of cell survival following exposure to modulated irradiation fields when cellular communication between differentially irradiated cell populations is present. This data is further evidence that refinement of existing radiobiological models to include indirect cell killing effects is required. (paper)

  5. Three-dimensional conformal radiotherapy for portal vein tumor thrombosis alone in advanced hepatocellular carcinoma

    Lee, Ju Hye Kim Dong Hyun; Ki, Yong Kan; Kim, Dong Won; Kim, Won Taek; Heo, Jeong; Woo, Hyun Young [Pusan National University Hospital, Pusan National University School of Medicine, Busan (Korea, Republic of); Nam, Ji Ho [Dept.of Radiation Oncology, Pusan National University Yangsan Hospital, Yangsan (Korea, Republic of)

    2014-09-15

    We sought to evaluate the clinical outcomes of 3-dimensional conformal radiation therapy (3D-CRT) for portal vein tumor thrombosis (PVTT) alone in patients with advanced hepatocellular carcinoma. We retrospectively analyzed data on 46 patients who received 3D-CRT for PVTT alone between June 2002 and December 2011. Response was evaluated following the Response Evaluation Criteria in Solid Tumors. Prognostic factors and 1-year survival rates were compared between responders and non-responders. Thirty-seven patients (80.4%) had category B Child-Pugh scores. The Eastern Cooperative Oncology Group performance status score was 2 in 20 patients. Thirty patients (65.2%) had main or bilateral PVTT. The median irradiation dose was 50 Gy (range, 35 to 60 Gy) and the daily median dose was 2 Gy (range, 2.0 to 2.5 Gy). PVTT response was classified as complete response in 3 patients (6.5%), partial response in 12 (26.1%), stable disease in 19 (41.3%), and progressive disease in 12 (26.1%). There were 2 cases of grade 3 toxicities during or 3 months after radiotherapy. Twelve patients in the responder group (15 patients) received at least 50 Gy irradiation, but about 84% of patients in the non-responder group received less than 50 Gy. The 1-year survival rate was 66.8% in responders and 27.4% in non-responders constituting a statistically significant difference (p = 0.008). Conformal radiotherapy for PVTT alone could be chosen as a palliative treatment modality in patients with unfavorable conditions (liver, patient, or tumor factors). However, more than 50 Gy of radiation may be required.

  6. Development of RTOG Consensus Guidelines for the Definition of the Clinical Target Volume for Postoperative Conformal Radiation Therapy for Prostate Cancer

    Purpose: To define a prostate fossa clinical target volume (PF-CTV) for Radiation Therapy Oncology Group (RTOG) trials using postoperative radiotherapy for prostate cancer. Methods and Materials: An RTOG-sponsored meeting was held to define an appropriate PF-CTV after radical prostatectomy. Data were presented describing radiographic failure patterns after surgery. Target volumes used in previous trials were reviewed. Using contours independently submitted by 13 radiation oncologists, a statistical imputation method derived a preliminary 'consensus' PF-CTV. Results: Starting from the model-derived CTV, consensus was reached for a CT image-based PF-CTV. The PF-CTV should extend superiorly from the level of the caudal vas deferens remnant to >8-12 mm inferior to vesicourethral anastomosis (VUA). Below the superior border of the pubic symphysis, the anterior border extends to the posterior aspect of the pubis and posteriorly to the rectum, where it may be concave at the level of the VUA. At this level, the lateral border extends to the levator ani. Above the pubic symphysis, the anterior border should encompass the posterior 1-2 cm of the bladder wall; posteriorly, it is bounded by the mesorectal fascia. At this level, the lateral border is the sacrorectogenitopubic fascia. Seminal vesicle remnants, if present, should be included in the CTV if there is pathologic evidence of their involvement. Conclusions: Consensus on postoperative PF-CTV for RT after prostatectomy was reached and is available as a CT image atlas on the RTOG website. This will allow uniformity in defining PF-CTV for clinical trials that include postprostatectomy RT.

  7. Spherically symmetric Riemannian manifolds of constant scalar curvature and their conformally flat representations

    Mach, Patryk

    2014-01-01

    All spherically symmetric Riemannian metrics of constant scalar curvature in any dimension can be written down in a simple form using areal coordinates. All spherical metrics are conformally flat, so we search for the conformally flat representations of these geometries. We find all solutions for the conformal factor in 3, 4 and 6 dimensions. We write them in closed form, either in terms of elliptic or elementary functions. We are particularly interested in 3-dimensional spaces because of the link to General Relativity. In particular, all 3-dimensional constant negative scalar curvature spherical manifolds can be embedded as constant mean curvature surfaces in appropriate Schwarzschild solutions. Our approach, although not the simplest one, is linked to the Lichnerowicz-York method of finding initial data for Einstein equations.

  8. The intercomparison of the dose distributions between conformation techniques with pions and photons

    To compare conformation radiation treatment with pions vs photons, dose volume histograms (DVH) to the critical organs, including the spinal cord, kidney, and intestine, were examined in a patient with retroperitoneal soft tissue sarcoma. For photon conformation treatment, the following techniques were used: 360 degree rotation conformation technique (photon conformation), 4 fixed field technique (photon 4-field), and 2-axis conformation technique (photon 2-axial conformation). According to the DVH reduction method, complication probability was estimated. The concave portion of the target was conformed by pion conformation treatment, but not by photon conformation treatment. Pion conformation for the intestine showed the best DVH, whereas photon 4-field technique showed the worst DVH. For the kidney, pion conformation showed better DVH as compared with any other photon conformation treatment technique. In the spinal cord, photon 2-axial conformation was far superior, followed by pion conformation and then photon conformation and 4-field technique. A 2-axial technique showed a bigger inhomogeneity inside the target volume which is critical in curative treatment. TD 50 was 72 Gy for pion conformation, 53 Gy for photon conformation, 51 Gy for photon 4-field, and 68 Gy for photon 2-axial conformation. Complication probabilities for these conformation techniques at 60 Gy were 3%, 85%, 97%, and 9%. In view of tumor control probabilities, pion seems to have the biggest therapeutic ratio among these techniques. (N.K.)

  9. Conformal Bootstrap in Embedding Space

    Fortin, Jean-François

    2016-01-01

    It is shown how to obtain conformal blocks from embedding space with the help of the operator product expansion. The minimal conformal block originates from scalar exchange in a four-point correlation functions of four scalars. All remaining conformal blocks are simple derivatives of the minimal conformal block. With the help of the orthogonality properties of the conformal blocks, the analytic conformal bootstrap can be implemented directly in embedding space, leading to a Jacobi-like definition of conformal field theories.

  10. Conformal bootstrap in embedding space

    Fortin, Jean-François; Skiba, Witold

    2016-05-01

    It is shown how to obtain conformal blocks from embedding space with the help of the operator product expansion. The minimal conformal block originates from scalar exchange in a four-point correlation function of four scalars. All remaining conformal blocks are simple derivatives of the minimal conformal block. With the help of the orthogonality properties of the conformal blocks, the analytic conformal bootstrap can be implemented directly in embedding space, leading to a Jacobi-like definition of conformal field theories.

  11. Use of 3-dimensional body scans for body-image research.

    Domina, Tanya; Heuberger, Roschelle; MacGillivray, Maureen

    2008-04-01

    This preliminary study explored the use of highly realistic 3-dimensional body-scan images as a potential tool, taking advantage of a much more specific and expanded representation of the entire body. Traditionally, body-image research makes use of various contour drawing scales whose 2-dimensional figures increase proportionately and do not match the shape of many women. The study tested whether body-scanned images (N = 85) could be consistently "matched" to individual figures on a contour drawing scale. Internal consistency and interrater reliability were calculated and high coefficients were observed (alpha = .97, kappa = .80). The potential of utilizing 3-dimensional images either as more realistic somatotypes in contour-rating scales or as a measurement of body-image satisfaction using computer manipulation of a digital image is discussed. PMID:18556919

  12. The application of 3-dimensional CAT scan reconstruction for maxillofacial deformities

    It has been found very useful to recognize craniofacial deformities 3-dimensionally, and to observe 3-D Cat scan reconstructions that have been performed by others. Thus, starting in 1985, we have developed a 3-D CT system that combines conventional X-ray CAT scan hardware to a 3-Dimensional display software. In this paper we report on our 3-CT system, its basic algorithm, and its basic processes, i.e., the threshold process, the perspective process, the shading process and the display. The mixture shading which we have developed makes 3-D displays clearer and more natural. Also, we have applied our 3-D display to 39 cases of maxillofacial diformities. (author)

  13. Conditioned Media From Adipose-Derived Stromal Cells Accelerates Healing in 3-Dimensional Skin Cultures.

    Collawn, Sherry S; Mobley, James A; Banerjee, N Sanjib; Chow, Louise T

    2016-04-01

    Wound healing involves a number of factors that results in the production of a "closed" wound. Studies have shown, in animal models, acceleration of wound healing with the addition of adipose-derived stromal cells (ADSC). The cause for the positive effect which these cells have on wound healing has not been elucidated. We have previously shown that addition of ADSC to the dermal equivalent in 3-dimensional skin cultures accelerates reepithelialization. We now demonstrate that conditioned media (CM) from cultured ADSC produced a similar rate of healing. This result suggests that a feedback from the 3-dimensional epithelial cultures to ADSC was not necessary to effect the accelerated reepithelialization. Mass spectrometry of CM from ADSC and primary human fibroblasts revealed differences in secretomes, some of which might have roles in the accelerating wound healing. Thus, the use of CM has provided some preliminary information on a possible mode of action. PMID:26954733

  14. DYNAMICAL CONSISTENCE IN 3-DIMENSIONAL TYPE-K COMPETITIVE LOTKA-VOLTERRA SYSTEM

    2012-01-01

    A 3-dimensional type-K competitive Lotka-Volterra system is considered in this paper. Two discretization schemes are applied to the system with an positive interior fixed point, and two corresponding discrete systems are obtained. By analyzing the local dynamics of the corresponding discrete system near the interior fixed point, it is showed that this system is not dynamically consistent with the continuous counterpart system.

  15. Energy Sources of the Dominant Frequency Dependent 3-dimensional Atmospheric Modes

    Schubert, S.

    1985-01-01

    The energy sources and sinks associated with the zonally asymmetric winter mean flow are investigated as part of an on-going study of atmospheric variability. Distinctly different horizontal structures for the long, intermediate and short time scale atmospheric variations were noted. In previous observations, the 3-dimensional structure of the fluctuations is investigated and the relative roles of barotropic and baroclinic terms are assessed.

  16. BPS operators from the Wilson loop in the 3-dimensional supersymmetric Chern-Simons theory

    Fujita, Mitsutoshi

    2009-01-01

    We consider the small deformation of the pointlike Wilson loop in the 3-dimensional N=6 superconformal Chern-Simons theory. By Taylor expansion of the pointlike Wilson loop in powers of the loop variables, we obtain the BPS operators that correspond to the excited string states of the dual IIA string theory on the pp wave background. The BPS conditions of the Wilson loop constrain both the loop variables and the forms of the operators obtained in the Taylor expansion.

  17. 3-dimensional eddy current analysis of a conducting shell of a superconducting generator by using IBIEM

    To ensure reliable operation of superconducting field windings of a superconducting generator it is necessary to screen the field windings from time-varying magnetic fields. An electrothermal shield is used for this screening in order to protect the superconducting material from quench phenomenon. This screening effect is due to the eddy currents in the electrothermal shield. In this paper, these eddy currents in the conducting shell are analyzed numerically by using 3-dimensional indirect boundary integral equation method (IBIEM)

  18. Manufacture of Near Net Shaped 3- Dimensional Components for Industrial Applications

    Kennedy, David; Brosnan, Donal

    2005-01-01

    The development of near net shape 3-Dimensional products for industrial applications has been one main goal for Manufacturing Industries over the last few decades. Processes such as polymer blow moulding and its various stages of development, glass forming, extrusion, forging, centrifugal and sand casting, bulge forming and vacuum forming are typical processes that have contributed to this development. Current practices centre on Surface coatings, Rapid Prototyping, laser forming and nanotech...

  19. The Effect of Flattening Filter Free on Three-dimensional Conformal Radiation Therapy (3D-CRT), Intensity-Modulated Radiation Therapy (IMRT), and Volumetric Modulated Arc Therapy (VMAT) Plans for Metastatic Brain Tumors from Non-small Cell Lung Cancer.

    Shi, Li-Wan; Lai, You-Qun; Lin, Qin; Ha, Hui-Ming; Fu, Li-Rong

    2015-07-01

    Flattening filter free (FFF) may affect outcome measures of radiotherapy. The objective of this study is to compare the dosimetric parameters in three types of radiotherapy plans, three-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and volumetric modulated arc therapy (VMAT), with or without the flattening filter (FF), developed for the treatment of metastatic brain tumors from non-small cell lung cancer (NSCLC). From July 2013 to October 2013, 3D-CRT, IMRT, and VMAT treatment plans were designed using 6 MV and 10 MV, with and without FF, for 10 patients with brain metastasis from NSCLC. The evaluation of the treatment plans included homogeneity index (HI), conformity index (CI), monitor units (MU), mean dose (Dmean), treatment time, and the influence of FFF on volumes. There was no difference in CI or HI between FFF and FF models with 3D-CRT, IMRT, and VMAT plans. At 6 MV, a lower Dmean was seen in the FFF model of 3D-CRT and in the VMAT plan at 10 MV. In the IMRT 6 MV, IMRT 10 MV, and VMAT 10 MV plans, higher MUs were seen in the FFF models. FFF treatments are similar in quality to FF plans, generally lead to more monitor units, and are associated with shorter treatment times. FFF plans ranked by the order of superiority in terms of a time advantage are VMAT, 3D-CRT, and IMRT. PMID:26011493

  20. Is the alpha-beta ratio of prostate cancer really low? A prospective, non-randomized trial comparing standard and hyperfractionated conformal radiation therapy

    Background and purpose: The objectives of the current study were to compare genito-urinary (GU) and gastro-intestinal (GI) toxicities as well as biochemical control (bRFS) in prostate cancer, utilizing conventional (2.0 Gy daily) (STD) or hyperfractionated (HFX) conformal irradiation (CRT). HFX (1.2 Gy BID) was chosen as a radiobiological method to try to reduce long term sequelae without compromising local control. Patients and methods: Three-hundred-and-seventy consecutive patients (pts) entered this prospective, non-randomized trial in the period January 1993-January 2003; 209 were treated with STD and 161 with HFX CRT. All were evaluable for acute toxicity analysis, 179 (STD) and 151 pts (HFX) being evaluable for late sequelae and bRFS analyses. Pt characteristics were not statistically different in the two groups. CRT consisted of a 4-field technique for prostate and/or pelvic nodes and a 5-field boost with rectal shielding. Median doses were 74 and 79.2 Gy for STD and HFX patients respectively, the latter dose being isoeffective for tumour control assuming α/β=10 (EQD2=73.9 Gy). Median follow-up was 29.4 months (25.2 mos for STD; 37.7 mos for HFX; P<0.01). The two regimens were compared in terms of acute and late GU and GI toxicities and 5-year bRFS by univariate and multivariate analyses. Results: Acute grade≥2 GU toxicity was higher in the STD group (48.6% versus 37.3% in HFX, P=0.03), while no significant difference was found for acute GI toxicity. Late grade≥2 GU and GI toxicities were lower in the HFX group (5-year actuarial rate: GU: 10.1% versus 20.3%, P=0.05; GI: 6.0% versus 10.6%, P=0.18). Five-year bRFS were 70% (±13.8%, 95% CI) and 82.6% (±7.2%) for STD and HFX, respectively (P=0.44); a trend favouring HFX was found in the subgroup of pts who did not receive hormonal therapy (5-year bRFS: 85.9%±12.4% versus 63.9%±23.8%, P=0.15). Multivariate analysis revealed only risk groups and age statistically related to bRFS but not fractionation

  1. Application of 3-dimensional digital subtraction technique in the diagnosing and treating malignant esophageal stenosis

    Objective: To evaluate 3-dimensional digital subtraction technique in diagnosing and treating the malignant esophageal stenosis. Methods: After oral administration of contrast media, both two-dimensional and three-dimensional digital subtraction radiography of narrowed segment of esophagus were performed in forty patients with malignant esophageal stenosis caused by advanced esophageal carcinoma. The images obtained from 3-dimensional digital subtraction technique were compared with the images of the same patient's conventional esophageal air-barium double contrast pictures and 2-dimensional digital subtraction pictures. The results were analyzed. Results: Three-dimensional digital subtraction images could well display the position of the malignant esophageal stenosis. On the images the lesion's length could be precisely measured, the lesion's ulcer and perforation shape could be clearly demonstrated, and subtler esophageal fistula could be detected, which was very helpful for accurately localizing the lesion and selecting suitable endo-esophageal stent. Conclusion: The 3-dimensional digital subtraction technique is very useful in diagnosing malignant esophageal stenosis. With the help of the 3D images the lesion can be precisely localized and the suitable esophageal stent can be effectively selected and placed. (authors)

  2. Conformal invariance in supergravity

    In this thesis the author explains the role of conformal invariance in supergravity. He presents the complete structure of extended conformal supergravity for N <= 4. The outline of this work is as follows. In chapter 2 he briefly summarizes the essential properties of supersymmetry and supergravity and indicates the use of conformal invariance in supergravity. The idea that the introduction of additional symmetry transformations can make clear the structure of a field theory is not reserved to supergravity only. By means of some simple examples it is shown in chapter 3 how one can always introduce additional gauge transformations in a theory of massive vector fields. Moreover it is shown how the gauge invariant formulation sometimes explains the quantum mechanical properties of the theory. In chapter 4 the author defines the conformal transformations and summarizes their main properties. He explains how these conformal transformations can be used to analyse the structure of gravity. The supersymmetric extension of these results is discussed in chapter 5. Here he describes as an example how N=1 supergravity can be reformulated in a conformally-invariant way. He also shows that beyond N=1 the gauge fields of the superconformal symmetries do not constitute an off-shell field representation of extended conformal supergravity. Therefore, in chapter 6, a systematic method to construct the off-shell formulation of all extended conformal supergravity theories with N <= 4 is developed. As an example he uses this method to construct N=1 conformal supergravity. Finally, in chapter 7 N=4 conformal supergravity is discussed. (Auth.)

  3. An Improved Approach to External Beam Radiation Therapy for Intra-Abdominal Cavity Lesions for Rural Cancer Centers

    Radiation therapy of abdominal lesions is problematic at best. The proximity of highly critical structures, tumor locations, and necessary margins combine to make prescription dose delivery with conventional 3-dimensional (3D) conformal techniques difficult. Others have tried to overcome these hurdles with newer modalities including intra-operative radiation therapy (IORT), intensity modulated radiation therapy (IMRT), and heavy particle irradiation. These techniques have had moderate success but are not readily available and are therefore limited in application. These factors have lead to the development of a modified, noncoplanar 4-field box technique that demonstrates significant improvement in critical structure sparing, i.e., kidney(s), bowel, and liver doses reduced while simultaneously improving isodose coverage to the target

  4. Conformal three dimensional radiotherapy treatment planning in Lund

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

    1995-12-01

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

  5. Conformal three dimensional radiotherapy treatment planning in Lund

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

  6. Radiation

    The basic facts about radiation are explained, along with some simple and natural ways of combating its ill-effects, based on ancient healing wisdom as well as the latest biochemical and technological research. Details are also given of the diet that saved thousands of lives in Nagasaki after the Atomic bomb attack. Special comment is made on the use of radiation for food processing. (U.K.)

  7. Dosimetric Comparison of Volumetric Modulated Arc Therapy, Static Field Intensity Modulated Radiation Therapy, and 3D Conformal Planning for the Treatment of a Right-Sided Reconstructed Chest Wall and Regional Nodal Case

    Vishruta A. Dumane

    2014-01-01

    Full Text Available We compared 3D conformal planning, static field intensity modulated radiation therapy (IMRT, and volumetric modulated arc therapy (VMAT to investigate the suitable treatment plan and delivery method for a right-sided reconstructed chest wall and nodal case. The dose prescribed for the reconstructed chest wall and regional nodes was 50.4 Gy. Plans were compared for target coverage and doses of the lungs, heart, contralateral breast, and healthy tissue. All plans achieved acceptable coverage of the target and IMNs. The best right lung sparing achieved with 3D was a V20 Gy of 31.09%. Compared to it, VMAT reduced the same by 10.85% and improved the CI and HI over 3D by 18.75% and 2%, respectively. The ipsilateral lung V5 Gy to V20 Gy decreased with VMAT over IMRT by as high as 17.1%. The contralateral lung V5 Gy was also lowered with VMAT compared to IMRT by 16.22%. The MU and treatment beams were lowered with VMAT over IMRT by 30% and 10, respectively, decreasing the treatment time by >50%. VMAT was the treatment plan and delivery method of choice for this case due to a combination of improved lung sparing and reduced treatment time without compromising target coverage.

  8. Standard fractionation intensity modulated radiation therapy (IMRT) of primary and recurrent glioblastoma multiforme

    Intensity-modulated radiation therapy (IMRT) affords unparalleled capacity to deliver conformal radiation doses to tumors in the central nervous system. However, to date, there are few reported outcomes from using IMRT, either alone or as a boost technique, for standard fractionation radiotherapy for glioblastoma multiforme (GBM). Forty-two patients were treated with IMRT alone (72%) or as a boost (28%) after 3-dimensional conformal radiation therapy (3D-CRT). Thirty-three patients with primary disease and 9 patients with recurrent tumors were included. Thirty-four patients (81%) had surgery, with gross tumor resection in 13 patients (36%); 22 patients (53%) received chemo-radiotherapy. The median total radiation dose for all patients was 60 Gy with a range from 30.6 to 74 Gy. Standard fractions of 1.8 Gy/day to 2.0 Gy/day were utilized. Median survival was 8.7 months, with 37 patients (88%) deceased at last contact. Nonparametric analysis showed no survival difference in IMRT-boost vs. IMRT-only groups. While technically feasible, preliminary results suggest delivering standard radiation doses by IMRT did not improve survival outcomes in this series compared to historical controls. In light of this lack of a survival benefit and the costs associated with use of IMRT, future prospective trials are needed to evaluate non-survival endpoints such as quality of life and functional preservation. Short of such evidence, the use of IMRT for treatment of GBM needs to be carefully rationalized

  9. Radiation

    Exposure to solar and ionizing radiation increases the risk for cancer in humans. Some 5% of solar radiation is within the ultraviolet spectrum and may cause both malignant melanoma and non-melanocytic skin cancer; the latter is regarded as a benign disease and is accordingly not included in our estimation of avoidable cancers. Under the assumption that the rate of occurrence of malignant melanoma of the buttocks of both men and women and of the scalp of women would apply to all parts of the body in people completely unexposed to solar radiation, it was estimated that approximately 95% of all malignant melanomas arising in the Nordic populations around the year 2000 will be due to exposure to natural ultraviolet radiation, equivalent to an annual number of about 4700 cases, with 2100 in men and 2600 in women, or some 4% of all cancers notified. Exposure to ionizing radiation in the Nordic countries occurs at an average effective dose per capita per year of about 3 mSv (Iceland, 1.1 mSv) from natural sources, and about 1 mSv from man-made sources. While the natural sources are primarily radon in indoor air, natural radionuclides in food, cosmic radiation and gamma radiation from soil and building materials, the man-made sources are dominated by the diagnostic and therapeutic use of ionizing radiation. On the basis of measured levels of radon in Nordic dwellings and associated risk estimates for lung cancer derived from well-conducted epidemiological studies, we estimated that about 180 cases of lung cancer (1% of all lung cancer cases) per year could be avoided in the Nordic countries around the year 2000 if indoor exposure to radon were eliminated, and that an additional 720 cases (6%) could be avoided annually if either radon or tobacco smoking were eliminated. Similarly, it was estimated that the exposure of the Nordic populations to natural sources of ionizing radiation other than radon and to medical sources will each give rise to an annual total of 2120

  10. Conformal Symmetry and Unification

    Pawlowski, M

    1998-01-01

    The Weyl-Weinberg-Salam model is presented. It is based on the local conformal gauge symmetry. The model identifies the Higgs scalar field in SM with the Penrose-Chernikov-Tagirov scalar field of the conformal theory of gravity. Higgs mechanism for generation of particle masses is replaced by the originated in Weyl's ideas conformal gauge scale fixing. Scalar field is no longer a dynamical field of the model and does not lead to quantum particle-like excitations that could be observed in HE experiments. Cosmological constant is naturally generated by the scalar quadric term. The model admits Weyl vector bosons that can mix with photon and weak bosons.

  11. Three-dimensional topology optimized electrically-small conformal antenna

    Erentok, Aycan; Sigmund, Ole

    A three-dimensional (3D) conductor-based conformal electrically small antenna is obtained using a topology optimization method. The optimization method distributes a certain amount of conductive material to a designated design domain such that the material layout defines an electrically small rad...... radiator fed by a coaxial cable over a ground plane. Preliminary investigations show that topology optimization method produced a conformal ESA design that has a radiation efficiency of approximately 80% at 300 MHz....

  12. 胸部肿瘤三维适形放疗致放射性肺炎的相关因素分析%Analysis of the Related Factors of Three Dimensional Conformal Radiotherapy for Radiation Pneumonia in Chest Tumor

    吴晓圆

    2016-01-01

    目的:研究分析三维适形放疗(3DCRT)导致的放射性肺炎相关因素,为临床治疗提供参考。方法根据2010年1月~2013年4月我院的1200例胸部肿瘤患者来进行研究分析,记录接受三维适形放疗的患者放疗结束后0.5~1.5年内的RP发生情况,对患者的相关因素对其发生率的影响进行分析。结果放射性肺炎患者共180例,有1级患者119例,占总数的66%,2级患者43例,占总数的24%,3级患者14例,占总数的8%,4级患者4例,占总数的2%。结论胸部肿瘤患者的糖尿病、阻塞性肺炎、COPD等疾病为高危因素,会对患者的MLD、V20、V30等产生影响,患者的年龄、性别、吸烟史、分期等和放射性肺炎发生率无显著关联性。%Objective To study and analyze the related factors caused by three-dimensional conformal radiotherapy (3DCRT), and to provide reference for clinical treatment.Methods From January 2010 to April 2013, 1 200 patients with chest tumor patients to study and analyze, record the three months to a year and a half after the completion of three-dimensional conformal radiotherapy in patients with RP, the impact of the relevant factors on the incidence of patients.Results A total of 180 patients with radiation pneumonia, 119 cases, accounting for 66% of the total, 2 cases, 43 cases, accounting for 14 of the total, 3 cases, accounting for 8% of the total, 4 cases, 4 cases, accounting for 2%.Conclusion The risk factors of diabetes, obstructive pneumonia, COPD and other diseases in patients with breast cancer, the patients with V20, V30, MLD and other factors, the patient's age, gender, smoking history, staging, etc.

  13. Conformal Invariant Teleparallel Cosmology

    Momeni, Davood

    2014-01-01

    Teleparallel gravities revisited under conformal transformations. We find several kinds of the Lagrangians, all invariant under conformal transformation. Motivated by observational data,we investigate FRW cosmological solutions in the vacuum. To include the matter fields,we mention that we have few possibilities for our matter Lagrangian to respect the conformal symmetry. FRW equations,have been derived in terms of the effective energy and pressure components. In vacuum we find an exact solution for Hubble parameter which is compatible with the observational data but it is valid only in the range of $z\\ge 0.07$. Scalar torsion models in which we have the extra scalar field is examined under FRW spacetime. We introduce the potential term $\\frac{1}{4!}\\mu\\phi^4$ as the minimal self interaction with conformal symmetry.

  14. [Conformers of carnosine].

    Kliuev, S A

    2006-01-01

    The geometric and energetic parameters of most stable conformations of carnosine were calculated by the semiempirical guantum-chemical method PM3. The carnosine-water-zinc (II) clusters were simulated. PMID:16909845

  15. Development of a 3-dimensional seismic isolation floor for computer systems

    In this paper, we investigated the applicability of a seismic isolation floor as a method for protecting computer systems from strong earthquakes, such as computer systems in nuclear power plants. Assuming that the computer system is guaranteed for 250 cm/s2 of input acceleration in the horizontal and vertical directions as the seismic performance, the basic design specification of the seismic isolation floor is considered as follows. Against S1 level earthquakes, the maximum acceleration response of the seismic isolation floor in the horizontal and vertical directions is kept less than 250 cm/s2 to maintain continuous computer operation. Against S2 level earthquakes, the isolation floor allows large horizontal movement and large displacement of the isolation devices to reduce the acceleration response, although it is not guaranteed to be less than 250 cm/s2. By reducing the acceleration response, however, serious damage to the computer systems is reduced, so that they can be restarted after an earthquake. Usually, seismic isolation floor systems permit 2-dimensional (horizontal) isolation. However, in the case of just-under-seated earthquakes, which have large vertical components, the vertical acceleration response of this system is amplified by the lateral vibration of the frame of the isolation floor. Therefore, in this study a 3-dimensional seismic isolation floor, including vertical isolation, was developed. This paper describes 1) the experimental results of the response characteristics of the 3-dimensional seismic isolation floor built as a trial using a 3-dimensional shaking table, and 2) comparison of a 2-dimensional analytical model, for motion in one horizontal direction and the vertical direction, to experimental results. (J.P.N.)

  16. 3-Dimensional quantitative detection of nanoparticle content in biological tissue samples after local cancer treatment

    Rahn, Helene, E-mail: helene.rahn@gmail.com [Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, Technische Universitaet Dresden, Dresden 01069 (Germany); Alexiou, Christoph [ENT-Department, Section for Experimental Oncology and Nanomedicine (Else Kröner-Fresenius-Stiftungsprofessur), University Hospital Erlangen, Waldstraße 1, Erlangen 91054 (Germany); Trahms, Lutz [Physikalisch-Technische Bundesanstalt, Abbestraße 2-12, Berlin 10587 (Germany); Odenbach, Stefan [Institute of Fluid Mechanics, Chair of Magnetofluiddynamics, Technische Universitaet Dresden, Dresden 01069 (Germany)

    2014-06-01

    X-ray computed tomography is nowadays used for a wide range of applications in medicine, science and technology. X-ray microcomputed tomography (XµCT) follows the same principles used for conventional medical CT scanners, but improves the spatial resolution to a few micrometers. We present an example of an application of X-ray microtomography, a study of 3-dimensional biodistribution, as along with the quantification of nanoparticle content in tumoral tissue after minimally invasive cancer therapy. One of these minimal invasive cancer treatments is magnetic drug targeting, where the magnetic nanoparticles are used as controllable drug carriers. The quantification is based on a calibration of the XµCT-equipment. The developed calibration procedure of the X-ray-µCT-equipment is based on a phantom system which allows the discrimination between the various gray values of the data set. These phantoms consist of a biological tissue substitute and magnetic nanoparticles. The phantoms have been studied with XµCT and have been examined magnetically. The obtained gray values and nanoparticle concentration lead to a calibration curve. This curve can be applied to tomographic data sets. Accordingly, this calibration enables a voxel-wise assignment of gray values in the digital tomographic data set to nanoparticle content. Thus, the calibration procedure enables a 3-dimensional study of nanoparticle distribution as well as concentration. - Highlights: • Local cancer treatments are promising in reducing negative side effects occurring during conventional chemotherapy. • The nanoparticles play an important role in delivering drugs to the designated area during local cancer treatments as magnetic drug targeting. • We study the nanoparticles distribution in tumor tissue after magnetic drug targeting with X-ray computed tomography. • We achieved a 3-dimensional quantification of the nanoparticles content in tumor tissue out of digital tomographic data.

  17. Formation and microstructural analysis of 3-dimensional titanium oxide structures via large surface electron beam irradiation

    Recently, in photo electronic devices industry, titanium oxide which was known to have good optical and electrical characteristic's been studied in the microstructural aspect to increase the conversion efficiency, such as making variable architecture, coating the titanium oxide nano-tube with the quantum dots which have higher band gap materials than this, etc. However, the process of making 3-dimensional titanium oxide structure with general deposition system such as hydrothermal growth, CVO, PVD and ALD had more variables and longer time consumption to make nano structures than electron beam irradiation case. Herein, we proceed with making new titanium oxide nano-screen-testing electron beam irradiation. The metal alkoxide composed of the 1 mol of titanium iso-propoxide and the 1 mol of acetylation reacted with water in propylene glycol methyl ether acetate and isopropyl alcohol solvent. After this process which made the bonding among Ti, O and other organics, the polymer solution was deposited on various types of substrate, such as anodized aluminum oxide mail. Kist. ac., Ag nano dots on SiO2 thin film, Au nano dots on SiO2 thin film, etc. The electron beam irradiation was progressed with the vertical accelerator facility of EB tech which was the company in Dijon, Korea The shape, microstructure and chemical composition of the irradiated polymers were characterized using TEM, XRD, Sem and EDS. The three types of Ti-Ox 3-dimensional structure were made; nano dot cluster, spike-like structure and dendrite structure. Each type of these structures was composed of different mircrostructures. Especially, the formation the 3-dimensional structures via electron beam irradiation was not only effected by the electron beam irradiation conditions but also effected by solution concentrate, conductivity and surface energy of substrate

  18. Quantum conformal mechanics

    Andrzejewski, K

    2015-01-01

    The quantum mechanics of one degree of freedom exhibiting the exact conformal SL(2,R) symmetry is presented. The starting point is the classification of the unitary irreducible representations of the SL(2,R) group (or, to some extent, its universal covering). The coordinate representation is defined as the basis diagonalizing the special conformal generator K. It is indicated how the resulting theory emerges from the canonical/geometric quantization of the Hamiltonian dynamics on the relevant coadjoint orbits.

  19. Quantum massive conformal gravity

    Faria, F. F.

    2016-01-01

    We first find the linear approximation of the second plus fourth order derivative massive conformal gravity action. Then we reduce the linearized action to separated second order derivative terms, which allows us to quantize the theory by using the standard first order canonical quantization method. It is shown that quantum massive conformal gravity is renormalizable but has ghost states. A possible decoupling of these ghost states at high energies is discussed.

  20. Quantum massive conformal gravity

    Faria, F. F.

    2016-04-01

    We first find the linear approximation of the second plus fourth order derivative massive conformal gravity action. Then we reduce the linearized action to separated second order derivative terms, which allows us to quantize the theory by using the standard first order canonical quantization method. It is shown that quantum massive conformal gravity is renormalizable but has ghost states. A possible decoupling of these ghost states at high energies is discussed.

  1. Quantum massive conformal gravity

    We first find the linear approximation of the second plus fourth order derivative massive conformal gravity action. Then we reduce the linearized action to separated second order derivative terms, which allows us to quantize the theory by using the standard first order canonical quantization method. It is shown that quantum massive conformal gravity is renormalizable but has ghost states. A possible decoupling of these ghost states at high energies is discussed. (orig.)

  2. Delineating the conformal window

    Frandsen, Mads Toudal; Pickup, Thomas; Teper, Michael

    We identify and characterise the conformal window in gauge theories relevant for beyond the standard model building, e.g. Technicolour, using the criteria of metric confinement and causal analytic couplings, which are known to be consistent with the phase diagram of supersymmetric QCD from Seiberg...... duality. Using these criteria we find perturbation theory to be consistent throughout the predicted conformal window for several of these gauge theories and we discuss recent lattice results in the light of our findings....

  3. BPS operators from the Wilson loop in the 3-dimensional supersymmetric Chern-Simons theory

    Fujita, Mitsutoshi

    2009-01-01

    We consider the small deformation of the point-like Wilson loop in the 3-dimensional $\\mathcal{N}=6$ superconformal Chern-Simons theory. By Taylor expansion of the point-like Wilson loop in powers of the loop variables, we obtain the BPS operators that correspond to the excited string states of the dual IIA string theory on the pp wave background. The BPS conditions of the Wilson loop constrain both the loop variables and the forms of the operators obtained in the Taylor expansion.

  4. Development of water packing mitigation scheme for MARS 3- dimensional thermal-hydraulic module

    Water packing mitigation scheme was developed to enhance the numerical stability and calculational efficiency of MARS 3-dimensional thermal-hydraulic module. The water packing phenomena is unphysical pressure spike which occurs in a two-phase system thermal-hydraulic code using Eulerian finite difference method. Great velocities developed from large pressure spike slow down the calculation efficiency due to the stability limit. Also, large pressure spike and subsequent low pressure can make errors in thermodynamic state table search. The developed water packing mitigation scheme was implemented in MARS3D module. It is shown from the results of some benchmark problema that numerical stability and calculational efficiency were improved

  5. Screening for proximal coronary artery anomalies with 3-dimensional MR coronary angiography

    Prakken, Niek H.; Cramer, Maarten J; Olimulder, Marlon A; Agostoni, Pierfrancesco; Mali, Willem P; Velthuis, Birgitta K

    2010-01-01

    Under 35 years of age, 14% of sudden cardiac death in athletes is caused by a coronary artery anomaly (CAA). Free-breathing 3-dimensional magnetic resonance coronary angiography (3D-MRCA) has the potential to screen for CAA in athletes and non-athletes as an addition to a clinical cardiac MRI protocol. A 360 healthy men and women (207 athletes and 153 non-athletes) aged 18–60 years (mean age 31 ± 11 years, 37% women) underwent standard cardiac MRI with an additional 3D-MRCA within a maximum o...

  6. Fractal dimensions from a 3-dimensional intermittency analysis in e+e- annihilation

    The intermittency structure of multihadronic e+e- annihilation is analyzed by evaluating the factorial moments F2-F5 in 3-dimensional Lorentz invariant phase space as a function of the resolution scale. We interpret our data in the language of fractal objects. It turns out that the fractal dimension depends on the resolution scale in a way that can be attributed to geometrical resolution effects and dynamical effects, such as the π0 Dalitz decay. The LUND 7.2 hadronization model provides an excellent description of the data. There is no indication of unexplained multiplicity fluctuations in small phase space regions. (orig.)

  7. Visualized fuelling process and 3 dimensional reactivity device and core monitor

    A new reactor fueling animated graphical display and a 3 dimensional view of the reactor core display are presented that are useful for the physics fuelling engineer, the Control Room Operators, the fuel handling operators and the fuel handling support engineers. Data is downloaded from the online fuelling computer to a data server that is network accessible. The fuelling display and 3Dview display can run on any network connected Computer. The animated graphical fuelling display offers a huge reduction in cognitive workload for all users. The authors recommend that animated graphical displays be developed and utilized wherever personnel have to visualize complex equipment operation. (author)

  8. Development of a 3-Dimensional Dosimetry System for Leksell Gamma Knife-Perfexion

    Yoon, KyoungJun; Kwak, Jungwon; Lee, DoHeui; Cho, Byungchul; Lee, Sangwook; Ahn, SeungDo

    2015-01-01

    The purpose of our study is to develop a new, 3-dimensional dosimetry system to verify the accuracy of dose deliveries in Leksell Gamma Knife-Perfexion TM (LGKP) (Elekta, Norcross, GA, USA). The instrument consists of a moving head phantom, an embedded thin active layer and a CCD camera system and was designed to be mounted to LGKP. As an active material concentrically located in the hemispheric head phantom, we choose Gafchromic EBT3 films and Gd2O2S;Tb phosphor sheets for dosimetric measure...

  9. Shaking test of 3-dimensional isolator by using air spring and rubber bearing

    A new 3-dimensional isolator is proposed, where a high-pressure air spring is mounted on a laminated rubber bearing. The vertical flexibility is induced by the air spring, while the horizontal one is primarily by the laminated rubber bearing. To examine the effectiveness of the above concept, shaking tests of experimental models were performed, where a concrete block weighing about 24 tons was mounted on the four isolators. For suppressing rocking motions, an inclined support method was also tested. The results were satisfactory and the effectiveness of new isolators was confirmed

  10. A novel solar cell fabricated with spiral photo-electrode for capturing sunlight 3-dimensionally

    LIU; Yong; SHEN; Hui

    2006-01-01

    A novel solar cell fabricated with spiral photo-electrode for capturing sunlight 3-dimensionally (3D-cell) is proposed in this paper. We studied its performance both in solar simulator and in nature sunlight. Spiral photo-electrode of 3D-cell can receive sunlight from all directions and therefore can track the sun passively. And it is much insensitive to solar azimuth angle and shade. In addition, it increases the area to obtain scattered sunlight and reflected light. Compared with the dye-sensitized solar cells using sandwich structure, it would be more advantageous in the sealing technique.

  11. Hamiltonian Analysis of 3-Dimensional Connection Dynamics in Bondi-like Coordinates

    Huang, Chao-Guang

    2016-01-01

    The Hamiltonian analysis for a 3-dimensional $SO(1,1)\\times T_+$-connection dynamics is conducted in a Bondi-like coordinate system.A null coframe with 5 independent variables and 9 connection coefficients are treated as basic configuration variables.All constraints and their consistency conditions, as well as the equations of motion,for the system are presented.There is no physical degree of freedom in the system as expected.The Ba\\~nados-Teitelboim-Zanelli spacetime as an example is used to check the analysis.

  12. Towards a mathematical definition of Coulomb branches of $3$-dimensional $\\mathcal N=4$ gauge theories, II

    Braverman, Alexander; Nakajima, Hiraku

    2016-01-01

    Consider the $3$-dimensional $\\mathcal N=4$ supersymmetric gauge theory associated with a compact Lie group $G_c$ and its quaternionic representation $\\mathbf M$. Physicists study its Coulomb branch, which is a noncompact hyper-K\\"ahler manifold with an $\\mathrm{SU}(2)$-action, possibly with singularities. We give a mathematical definition of the Coulomb branch as an affine algebraic variety with $\\mathbb C^\\times$-action when $\\mathbf M$ is of a form $\\mathbf N\\oplus\\mathbf N^*$, as the second step of the proposal given in arXiv:1503.03676.

  13. Spinorial Characterizations of Surfaces into 3-dimensional Pseudo-Riemannian Space Forms

    We give a spinorial characterization of isometrically immersed surfaces of arbitrary signature into 3-dimensional pseudo-Riemannian space forms. This generalizes a recent work of the first author for spacelike immersed Lorentzian surfaces in ℝ2,1 to other Lorentzian space forms. We also characterize immersions of Riemannian surfaces in these spaces. From this we can deduce analogous results for timelike immersions of Lorentzian surfaces in space forms of corresponding signature, as well as for spacelike and timelike immersions of surfaces of signature (0, 2), hence achieving a complete spinorial description for this class of pseudo-Riemannian immersions.

  14. The usefulness of 3-dimensional CT angiography for surgeries at the craniovertebral junction

    We preoperatively examined 77 patients for VA anomalies by 3-dimensional computed tomography angiography (3D-CTA) in order to avoid intraoperative vertebral artery (VA) injury during instrumentation surgery at the craniovertebral junction. An abnormal course of the VA in the extraosseous region was detected in 10 patients (13.0%), and a high-riding VA was identified in 21 patients (27.3%). The incidence of VA anomalies in the extraosseous and intraosseous regions was higher in patients with a congenital skeletal anomaly at the craniovertebral junction. Preoperative 3D-CTA allowed precise identification of anomalous VAs and reduction of the risk of intraoperative injury of the VA. (author)

  15. Physical and methodological aspects of the multimodality imaging and principles of the treatment planning for the conformal 3-D radiation therapy; Aspects physiques et methodologiques de l'imagerie multimodalites et principes de planification dosimetrique pour la radiotherapie conformationnelle tridimensionnelle

    Lefkopoulos, D.; Foulquier, J.N.; Petegnief, Y. [Hopital Tenon, Unite de Physique Medicale, 75 - Paris (France); Touboul, E. [Hopital Tenon, Service d' Oncologie-Radiotherapie, 75 - Paris (France); Petegnief, Y. [Hopital Tenon, Service de Medecine Nucleaire, 75 - Paris (France)

    2001-10-01

    The recent evolutions of the imaging modalities, the dose calculation models, the linear accelerators and the portal imaging permit to improve the quality of the conformal radiation therapy treatment planning. With DICOM protocols, the acquired imaging data coming from different modalities are treated by efficient image fusion algorithms and yield more precise target volumes and organs at risk. The transformation of the clinical target volumes (CTV) to planning target volumes (PTV) can be realised using advanced probabilistic techniques based on clinical experience. The treatment plans evaluation is based on the dose volume histograms. Their precision and clinical relevance are improved by the multimodality imaging and the advanced dose calculation models. The introduction of the inverse planning systems permitting to realize modulated intensity radiation therapy generates highly conformal dose distributions. All the previously cited complex techniques require the application of rigorous quality assurance programs. (author)

  16. 胸部肿瘤三维适形放疗急性放射性肺损伤相关因素的分析%Analysis of breast tumor dimensional conformal radiation therapy of acute radiation-induced lung injury related factors

    王友硕; 屈进文; 周美英; 熊菊方

    2015-01-01

    目的:对胸部肿瘤三维适形放疗急性放射性肺损伤相关因素开展分析。方法:随机选取我院2013年1月至2014年12月间收治的开展三维适形放疗治疗的胸部肿瘤患者200例,对患者的放疗开展时间、糖尿病史、心血管疾病史、年龄、性别、出现急性放射性肺损伤的时间等一般资料进行记录,并要对其放疗的总剂量,双肺的V5、V10、V20、V30及双肺所应用的平均剂量开展统计分析。结果:所选的200例应用三维适形放疗治疗的胸部肿瘤患者中,有30例患者发生了放射性肺损伤,其总的发生率为30%,其中有16例患者表现为急性放射性肺损伤,其所占比例为53.33%,导致患者发生急性放射性肺损伤的危险因素为:V30≥19%,V20≥27%,V10≥41%,V5≥56%;并且通过分析可以看出,当患者的总剂量大于等于56Gy时,患者发生急性放射性肺损伤的概率明显加大。结论:应用三维适形放疗开展治疗的胸部肿瘤患者发生急性放射性肺损伤的相关因素主要有:V30、V20、V10、V5及放疗总剂量。%Objective: Chest tumor dimensional conformal radiotherapy-related factors to carry out analysis of acute radiation-induced lung injury.Methods: Randomly selected in our hospital between January 2013 to December 2014 200 cases of breast cancer patients admitted to carry out three-dimensional conformal radiation therapy, the patient's radiation carried out time, history of diabetes, history of cardiovascular disease, age, sex, acute general information on radiation-induced lung injury in time to record, and you want to total dose of radiotherapy, lungs of V5, V10, V20, V30 and lungs average dose applied to carry out statistical analysis.Results: Breast cancer patients selected 200 cases of application of three-dimensional conformal radiation therapy, 30 patients developed radiation-induced lung injury, the total incidence of 30%, including 16 patients

  17. Automated, non-linear registration between 3-dimensional brain map and medical head image

    In this paper, we propose an automated, non-linear registration method between 3-dimensional medical head image and brain map in order to efficiently extract the regions of interest. In our method, input 3-dimensional image is registered into a reference image extracted from a brain map. The problems to be solved are automated, non-linear image matching procedure, and cost function which represents the similarity between two images. Non-linear matching is carried out by dividing the input image into connected partial regions, transforming the partial regions preserving connectivity among the adjacent images, evaluating the image similarity between the transformed regions of the input image and the correspondent regions of the reference image, and iteratively searching the optimal transformation of the partial regions. In order to measure the voxelwise similarity of multi-modal images, a cost function is introduced, which is based on the mutual information. Some experiments using MR images presented the effectiveness of the proposed method. (author)

  18. MR imaging of the knee joint with 3-dimensional gradient echo

    Authors considered and discussed whether various lesions of the knee joint can be diagnosed under the MR imaging condition with a pulse sequence of 3-dimensional fourier transformed gradient recalled acquisition in the steady state and what advantages the method has. The apparatus was 1.5T Signa (General Electric) equipped with surface coil for the knee. The consecutive 124 sagittal images of 0.8 mm thickness taken primarily for 3-dimensional reconstruction were processed to give any cross sections of coronary, horizontal, sagittal or further additional ones. Subjects were 243 knees (138 internal derangement and 105 osteoarthritis) whose lesions were confirmed by arthroscope or by arthrostomy after the MR imaging. Comparison of the MR imaging and surgical finding revealed that accuracy, specificity and sensitivity of the present MR imaging method were all >90% for diagnosis of internal derangement of anterior cruciate ligament and meniscus. For osteoarthritis, the method was thought useful for evaluation of the depth of cartilage deficit. (K.H.)

  19. Contactless 2-dimensional laser sensor for 3-dimensional wire position and tension measurements

    Prall, Matthias; Joehren, R; Ortjohann, H W; Reinhardt, M; Weinheimer, Ch

    2009-01-01

    We have developed a contact-free 2-dimensional laser sensor with which the position of wires can be measured in 3 dimensions with an accuracy of better than 10 micrometer and with which the tension of the wires can be determined with an accuracy of 0.04 N. These measurements can be made from a distance of 15 cm. The sensor consists of commercially available laser pointers, lenses, color filters and photodiodes. In our application we have used this laser sensor together with an automated 3 dimensional coordinate table. For a single position measurement, the laser sensor is moved by the 3-dimensional coordinate table in a plane and determines the coordinates at which the wires intersect with this plane. The position of the plane itself (the third coordinate) is given by the third axis of the measurement table which is perpendicular to this plane. The control and readout of the table and the readout of the laser sensor were realized with LabVIEW. The precision of the position measurement in the plane was determi...

  20. Crossover from 2-dimensional to 3-dimensional aggregations of clusters on square lattice substrates

    Cheng, Yi; Zhu, Yu-Hong; Pan, Qi-Fa; Yang, Bo; Tao, Xiang-Ming; Ye, Gao-Xiang

    2015-11-01

    A Monte Carlo study on the crossover from 2-dimensional to 3-dimensional aggregations of clusters is presented. Based on the traditional cluster-cluster aggregation (CCA) simulation, a modified growth model is proposed. The clusters (including single particles and their aggregates) diffuse with diffusion step length l (1 ≤ l ≤ 7) and aggregate on a square lattice substrate. If the number of particles contained in a cluster is larger than a critical size sc, the particles at the edge of the cluster have a possibility to jump onto the upper layer, which results in the crossover from 2-dimensional to 3-dimensional aggregations. Our simulation results are in good agreement with the experimental findings. Project supported by the National Natural Science Foundation of China (Grant Nos. 11374082 and 11074215), the Science Foundation of Zhejiang Province Department of Education, China (Grant No. Y201018280), the Fundamental Research Funds for Central Universities, China (Grant No. 2012QNA3010), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20100101110005).

  1. Morphological Control of Cells on 3-Dimensional Multi-Layer Nanotopographic Structures.

    Jeong, Heon-Ho; Noh, Young-Mu; Song, Hwan-Moon; Lee, Sang-Ho; Park, Jin-Sung; Lee, Chang-Soo

    2015-05-01

    The extracellular matrix (ECM) environment is known to play an important role in the process of various cell regulatory mechanisms. We have investigated the ability of 3-dimensional ECM geometries to induce morphological changes in cells. Bi-layer polymeric structures with submicron scale stripe patterns were fabricated using a two-step nano-imprinting technique, and the orientation angle (θ(α)) of the upper layer was controlled by changing its alignment with respect to the orientation of the bottom layer. When cells were grown on the mono-layer stripe structure with a single orientation, they elongated along the direction of the stripe pattern. On bi-layer polymer structures, the cell morphologies gradually changed and became rounded, with an increase of θα up to 90 degrees, but the polarities of these cells were still aligned along the orientation of the upper layer. As a result, we show that the polarity and the roundness of cells can be independently regulated by adjusting the orientation of 3-dimensional hierarchical ECM topography. PMID:26505024

  2. Unobservable Problem of Target Tracking with Bearing-only Measurements in 3-dimensional Space

    XU Zhi-gang; SHENG An-dong

    2008-01-01

    The bearings-only tracking (BOT) system is said to be observability if and only if the target motion parameters can be uniquely determined by noise-free bearing measurements. By utilizing the method of orthogonal vectors and characteristic of linear matrix equation, the problem of observability for BOT in noise-free bearings measurements from single observer is discussed based on the target and observer traveling in the 3-dimensional space. A proposition that BOT for target and observer traveling in the 3-dimensional space with constant acceleration remains unsolvable is presented and proved. By proving the proposition, it is also shown that some motion parameter ratios of target can be estimated under certain condition satisfied by measurements and time samples. The proposition is extended to arbitrary rank of manoeuvre for the observer and the target, which BOT remains unobservable property while the rank of target manoeuvre is higher than that of the observer manoeuvre. The theoretical analysis of this paper provides the guidelines for how the observer trajectory should be formulated to avoid unobservable state for BOT in practice application.

  3. 3-dimensional computer model to simulate fluid flow and contaminant transport through a rock fracture system

    A 3-dimensional fracture generating scheme is presented which can be used to simulate water flow and contaminant (solute) transport through fracture system of a rock. It is presently limited to water saturated conditions, zero permeability for the rock matrix, and steady state water flow, but allows for transient solute transport. The scheme creates finite planar plates of uniform thickness which represent fractures in 3-dimensional space. A given fracture (plate) has the following descriptors: center location, orientation, shape, areal extent and aperture. Each parameter can be described by an appropriate probability distribution. Individual fractures are generated to form an assemblage of a certain fracture density. All fracture intersections and boundary/fracture intersections are determined and deadend fractures are eliminated. Flow through the fracture assemblage is considered laminar and described by Poiseuille's law. The principle of mass conservation at each intersection is used to develop the global matrix equation, which is solved subject to specified boundary conditions to yield the head and flow distribution at each intersection. Solute transport is considered to be advective between intersections with complete mixing at each intersection. Solutes added to the flow system can be explicitly followed and concentration vs. time relationships can be determined anywhere in the system. Some examples are included

  4. Computer implementation of 3-dimensional stairs-appearance graph display of the neutron flux distribution in the reactor core

    A treatment method of displaying neutron flux distribution on the computer terminator with 3-dimensional stairs-appearance graph is described. Experiments show that this method and associated software written with BASIC are successful

  5. SECOND-ORDER OPTIMALITY CONDITIONS FOR OPTIMAL CONTROL PROBLEMS GOVERNED BY 3-DIMENSIONAL NEVIER-STOKES EQUATIONS

    2006-01-01

    This article is concerned with second-order necessary and sufficient optimality conditions for optimal control problems governed by 3-dimensional Navier-Stokes equations. The periodic state constraint is considered.

  6. Initial Efficacy Results of RTOG 0319: Three-Dimensional Conformal Radiation Therapy (3D-CRT) Confined to the Region of the Lumpectomy Cavity for Stage I/ II Breast Carcinoma

    Purpose: This prospective study (Radiation Therapy Oncology Group 0319) examines the use of three-dimensional conformal external beam radiotherapy (3D-CRT) to deliver accelerated partial breast irradiation (APBI). Initial data on efficacy and toxicity are presented. Methods and Materials: Patients with Stage I or II breast cancer with lesions ≤3 cm, negative margins and with ≤3 positive nodes were eligible. The 3D-CRT was 38.5 Gy in 3.85 Gy/fraction delivered 2x/day. Ipsilateral breast, ipsilateral nodal, contralateral breast, and distant failure (IBF, INF, CBF, DF) were estimated using the cumulative incidence method. Mastectomy-free, disease-free, and overall survival (MFS, DFS, OS) were recorded. The National Cancer Institute Common Terminology Criteria for Adverse Events, version 3, was used to grade acute and late toxicity. Results: Fifty-eight patients were entered and 52 patients are eligible and evaluable for efficacy. The median age of patients was 61 years with the following characteristics: 46% tumor size <1 cm; 87% invasive ductal histology; 94% American Joint Committee on Cancer Stage I; 65% postmenopausal; 83% no chemotherapy; and 71% with no hormone therapy. Median follow-up is 4.5 years (1.7-4.8). Four-year estimates (95% CI) of efficacy are: IBF 6% (0-12%) [4% within field (0-9%)]; INF 2% (0-6%); CBF 0%; DF 8% (0-15%); MFS 90% (78-96%); DFS 84% (71-92%); and OS 96% (85-99%). Only two (4%) Grade 3 toxicities were observed. Conclusions: Initial efficacy and toxicity using 3D-CRT to deliver APBI appears comparable to other experiences with similar follow-up. However, additional patients, further follow-up, and mature Phase III data are needed to evaluate the extent of application, limitations, and value of this particular form of APBI.

  7. Biomechanical 3-Dimensional Finite Element Analysis of Obturator Protheses Retained with Zygomatic and Dental Implants in Maxillary Defects

    Akay, Canan; Yaluğ, Suat

    2015-01-01

    Background The objective of this study was to investigate the stress distribution in the bone around zygomatic and dental implants for 3 different implant-retained obturator prostheses designs in a Aramany class IV maxillary defect using 3-dimensional finite element analysis (FEA). Material\\Methods A 3-dimensional finite element model of an Aramany class IV defect was created. Three different implant-retained obturator prostheses were modeled: model 1 with 1 zygomatic implant and 1 dental imp...

  8. Killing tensors and conformal Killing tensors from conformal Killing vectors

    Koutras has proposed some methods to construct reducible proper conformal Killing tensors and Killing tensors (which are, in general, irreducible) when a pair of orthogonal conformal Killing vectors exist in a given space. We give the completely general result demonstrating that this severe restriction of orthogonality is unnecessary. In addition, we correct and extend some results concerning Killing tensors constructed from a single conformal Killing vector. A number of examples demonstrate that it is possible to construct a much larger class of reducible proper conformal Killing tensors and Killing tensors than permitted by the Koutras algorithms. In particular, by showing that all conformal Killing tensors are reducible in conformally flat spaces, we have a method of constructing all conformal Killing tensors, and hence all the Killing tensors (which will in general be irreducible) of conformally flat spaces using their conformal Killing vectors

  9. Hypofractionated Radiation Therapy (66 Gy in 22 Fractions at 3 Gy per Fraction) for Favorable-Risk Prostate Cancer: Long-term Outcomes

    Purpose: To report long-term outcomes of low- and intermediate-risk prostate cancer patients treated with high-dose hypofractionated radiation therapy (HypoRT). Methods and Materials: Patients with low- and intermediate-risk prostate cancer were treated using 3-dimensional conformal radiation therapy to a dose of 66 Gy in 22 daily fractions of 3 Gy without hormonal therapy. A uniform 7-mm margin was created around the prostate for the planning target volume, and treatment was prescribed to the isocenter. Treatment was delivered using daily ultrasound image-guided radiation therapy. Common Terminology Criteria for Adverse Events, version 3.0, was used to prospectively score toxicity. Biochemical failure was defined as the nadir prostate-specific antigen level plus 2 ng/mL. Results: A total of 129 patients were treated between November 2002 and December 2005. With a median follow-up of 90 months, the 5- and 8-year actuarial biochemical control rates were 97% and 92%, respectively. The 5- and 8-year actuarial overall survival rates were 92% and 88%, respectively. Only 1 patient died from prostate cancer at 92 months after treatment, giving an 8-year actuarial cancer-specific survival of 98%. Radiation therapy was well tolerated, with 57% of patients not experiencing any acute gastrointestinal (GI) or genitourinary (GU) toxicity. For late toxicity, the worst grade ≥2 rate for GI and GU toxicity was 27% and 33%, respectively. There was no grade >3 toxicity. At last follow-up, the rate of grade ≥2 for both GI and GU toxicity was only 1.5%. Conclusions: Hypofractionation with 66 Gy in 22 fractions prescribed to the isocenter using 3-dimensional conformal radiation therapy produces excellent biochemical control rates, with moderate toxicity. However, this regimen cannot be extrapolated to the intensity modulated radiation therapy technique

  10. Hypofractionated Radiation Therapy (66 Gy in 22 Fractions at 3 Gy per Fraction) for Favorable-Risk Prostate Cancer: Long-term Outcomes

    Patel, Nita [Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Faria, Sergio, E-mail: sergio.faria@muhc.mcgill.ca [Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada); Cury, Fabio; David, Marc; Duclos, Marie; Shenouda, George; Ruo, Russell; Souhami, Luis [Department of Radiation Oncology, McGill University Health Centre, Montreal, Quebec (Canada)

    2013-07-01

    Purpose: To report long-term outcomes of low- and intermediate-risk prostate cancer patients treated with high-dose hypofractionated radiation therapy (HypoRT). Methods and Materials: Patients with low- and intermediate-risk prostate cancer were treated using 3-dimensional conformal radiation therapy to a dose of 66 Gy in 22 daily fractions of 3 Gy without hormonal therapy. A uniform 7-mm margin was created around the prostate for the planning target volume, and treatment was prescribed to the isocenter. Treatment was delivered using daily ultrasound image-guided radiation therapy. Common Terminology Criteria for Adverse Events, version 3.0, was used to prospectively score toxicity. Biochemical failure was defined as the nadir prostate-specific antigen level plus 2 ng/mL. Results: A total of 129 patients were treated between November 2002 and December 2005. With a median follow-up of 90 months, the 5- and 8-year actuarial biochemical control rates were 97% and 92%, respectively. The 5- and 8-year actuarial overall survival rates were 92% and 88%, respectively. Only 1 patient died from prostate cancer at 92 months after treatment, giving an 8-year actuarial cancer-specific survival of 98%. Radiation therapy was well tolerated, with 57% of patients not experiencing any acute gastrointestinal (GI) or genitourinary (GU) toxicity. For late toxicity, the worst grade ≥2 rate for GI and GU toxicity was 27% and 33%, respectively. There was no grade >3 toxicity. At last follow-up, the rate of grade ≥2 for both GI and GU toxicity was only 1.5%. Conclusions: Hypofractionation with 66 Gy in 22 fractions prescribed to the isocenter using 3-dimensional conformal radiation therapy produces excellent biochemical control rates, with moderate toxicity. However, this regimen cannot be extrapolated to the intensity modulated radiation therapy technique.

  11. Charged conformal Killing spinors

    We study the twistor equation on pseudo-Riemannian Spinc-manifolds whose solutions we call charged conformal Killing spinors (CCKSs). We derive several integrability conditions for the existence of CCKS and study their relations to spinor bilinears. A construction principle for Lorentzian manifolds admitting CCKS with nontrivial charge starting from CR-geometry is presented. We obtain a partial classification result in the Lorentzian case under the additional assumption that the associated Dirac current is normal conformal and complete the classification of manifolds admitting CCKS in all dimensions and signatures ≤5 which has recently been initiated in the study of supersymmetric field theories on curved space

  12. Simple computer program to model 3-dimensional underground heat flow with realistic boundary conditions

    Metz, P. D.

    A FORTRAN computer program called GROCS (GRound Coupled Systems) has been developed to study 3-dimensional underground heat flow. Features include the use of up to 30 finite elements or blocks of Earth which interact via finite difference heat flow equations and a subprogram which sets realistic time and depth dependent boundary conditions. No explicit consideration of mositure movement or freezing is given. GROCS has been used to model the thermal behavior of buried solar heat storage tanks (with and without insulation) and serpentine pipe fields for solar heat pump space conditioning systems. The program is available independently or in a form compatible with specially written TRNSYS component TYPE subroutines. The approach taken in the design of GROCS, the mathematics contained and the program architecture, are described. Then, the operation of the stand-alone version is explained. Finally, the validity of GROCS is discussed.

  13. Development of 3-dimensional lattice gas automata method and applicability to the triggering of vapor explosion

    It is pointed out that large-scale vapor explosion may occur during a severe accident of a nuclear power plant. It is important to predict the possibility of the vapor explosion for the accident management of the nuclear power plant during a severe accident. In the present study, 3-dimensional 15-velocity model was developed based on the 2-dimensional 9-velocity model. This proposed model is applied to the numerical simulation of triggering of vapor explosion, i.e. vapor film collapse behavior by external force and droplet atomization. The objective of the present research is to validate the applicability of this model to simulate the triggering of vapor explosion compared with experimental data. (author)

  14. Tracking Error analysis of Concentrator Photovoltaic Module Using Total 3-Dimensional Simulator

    Ota, Yasuyuki; Nishioka, Kensuke

    2011-12-01

    A 3-dimensional (3D) operating simulator for concentrator photovoltaic (CPV) module using triple-junction solar cell was developed. By connecting 3D equivalent circuit simulation for triple-junction solar cell and ray-trace simulation for optics model, the operating characteristics of CPV module were calculated. A typical flat Fresnel lens and homogenizer were adapted to the optics model. The influence of tracking error on the performance of CPV module was calculated. There was the correlation between the optical efficiency and Isc. However, Pm was not correlated with these values, and was strongly dependent on FF. We can use this total simulator for the evaluation and optimization from the light incidence to operating characteristic of CPV modules.

  15. Using 3-dimensional printing to create presurgical models for endodontic surgery.

    Bahcall, James K

    2014-09-01

    Advances in endodontic surgery--from both a technological and procedural perspective-have been significant over the last 18 years. Although these technologies and procedural enhancements have significantly improved endodontic surgical treatment outcomes, there is still an ongoing challenge of overcoming the limitations of interpreting preoperative 2-dimensional (2-D) radiographic representation of a 3-dimensional (3-D) in vivo surgical field. Cone-beam Computed Tomography (CBCT) has helped to address this issue by providing a 3-D enhancement of the 2-D radiograph. The next logical step to further improve a presurgical case 3-D assessment is to create a surgical model from the CBCT scan. The purpose of this article is to introduce 3-D printing of CBCT scans for creating presurgical models for endodontic surgery. PMID:25197746

  16. '3-Dimensional' TEM silicon-device analysis by combining plan-view and FIB sample preparation

    Cross-sectional transmission electron microscopy (TEM) analysis has become routinely used in semiconductor industry to support failure and yield analysis. Plan-view transmission electron microscopy analysis however is much less frequently performed. In this paper it is illustrated that plan-view transmission electron microscopy analysis can add valuable information in yield analysis studies, especially when crystal defects are involved. '3-Dimensional' information can be obtained by combining cross-sectional transmission electron microscopy analysis with plan-view analysis. If the available material is limited, it can become a difficult choice whether to go for a cross-sectional or a plan-view analysis. Therefore it was explored if a cross-sectional specimen could still be made out of a plan-view specimen, using the plan-view analysis to locate the failure site precisely. This has recently been successfully done using the in-situ lift-out technique in the focused ion beam machine

  17. Reference Trajectory Generation for 3-Dimensional Walking of a Humanoid Robot

    2007-01-01

    Humanoid walking planning is a complicated task because of the high number of degrees of freedom (DOFs) and the variable mechanical structure during walking. In this paper, a planning method for 3-dimensional (3-D) walking movements was developed based on a model of a typical humanoid robot with 12 DOFs on the lower body. The planning process includes trajectory generation for the hip, ankle, and knee joints in the Cartesian space. The balance of the robot was ensured by adjusting the hip motion. The angles for each DOF were obtained from 3-D kinematics calculation. The calculation gave reference trajectories of all the DOFs on the humanoid robot which were used to control the real robot. The simulation results show that the method is effective.

  18. Towards a mathematical definition of Coulomb branches of $3$-dimensional $\\mathcal N=4$ gauge theories, I

    Nakajima, Hiraku

    2015-01-01

    Consider the $3$-dimensional $\\mathcal N=4$ supersymmetric gauge theory associated with a compact Lie group $G$ and its quaternionic representation $\\mathbf M$. Physicists study its Coulomb branch, which is a noncompact hyper-K\\"ahler manifold, such as instanton moduli spaces on $\\mathbb R^4$, $SU(2)$-monopole moduli spaces on $\\mathbb R^3$, etc. In this paper and its sequel, we propose a mathematical definition of the coordinate ring of the Coulomb branch, using the vanishing cycle cohomology group of a certain moduli space for a gauged $\\sigma$-model on the $2$-sphere associated with $(G,\\mathbf M)$. In this first part, we check that the cohomology group has the correct graded dimensions expected from the monopole formula proposed by Cremonesi, Hanany and Zaffaroni arXiv:1309.2657. A ring structure (on the cohomology of a modified moduli space) will be introduced in the sequel of this paper.

  19. A 3-Dimensional Cockpit Display with Traffic and Terrain Information for the Small Aircraft Transportation System

    UijtdeHaag, Maarten; Thomas, Robert; Rankin, James R.

    2004-01-01

    The report discusses the architecture and the flight test results of a 3-Dimensional Cockpit Display of Traffic and terrain Information (3D-CDTI). The presented 3D-CDTI is a perspective display format that combines existing Synthetic Vision System (SVS) research and Automatic Dependent Surveillance-Broadcast (ADS-B) technology to improve the pilot's situational awareness. The goal of the 3D-CDTI is to contribute to the development of new display concepts for NASA's Small Aircraft Transportation System research program. Papers were presented at the PLANS 2002 meeting and the ION-GPS 2002 meeting. The contents of this report are derived from the results discussed in those papers.

  20. DIEP Flap Breast Reconstruction Using 3-dimensional Surface Imaging and a Printed Mold

    Koichi Tomita, MD, PhD

    2015-03-01

    Full Text Available Summary: Recent advances in 3-dimensional (3D surface imaging technologies allow for digital quantification of complex breast tissue. We performed 11 unilateral breast reconstructions with deep inferior epigastric artery perforator (DIEP flaps (5 immediate, 6 delayed using 3D surface imaging for easier surgery planning and 3D-printed molds for shaping the breast neoparenchyma. A single- or double-pedicle flap was preoperatively planned according to the estimated tissue volume required and estimated total flap volume. The DIEP flap was then intraoperatively shaped with a 3D-printed mold that was based on a horizontally inverted shape of the contralateral breast. Cosmetic outcomes were assessed as satisfactory, as confirmed by the postoperative 3D measurements of bilateral breasts. We believe that DIEP flap reconstruction assisted with 3D surface imaging and a 3D-printed mold is a simple and quick method for rebuilding a symmetric breast.

  1. DIEP Flap Breast Reconstruction Using 3-dimensional Surface Imaging and a Printed Mold.

    Tomita, Koichi; Yano, Kenji; Hata, Yuki; Nishibayashi, Akimitsu; Hosokawa, Ko

    2015-03-01

    Recent advances in 3-dimensional (3D) surface imaging technologies allow for digital quantification of complex breast tissue. We performed 11 unilateral breast reconstructions with deep inferior epigastric artery perforator (DIEP) flaps (5 immediate, 6 delayed) using 3D surface imaging for easier surgery planning and 3D-printed molds for shaping the breast neoparenchyma. A single- or double-pedicle flap was preoperatively planned according to the estimated tissue volume required and estimated total flap volume. The DIEP flap was then intraoperatively shaped with a 3D-printed mold that was based on a horizontally inverted shape of the contralateral breast. Cosmetic outcomes were assessed as satisfactory, as confirmed by the postoperative 3D measurements of bilateral breasts. We believe that DIEP flap reconstruction assisted with 3D surface imaging and a 3D-printed mold is a simple and quick method for rebuilding a symmetric breast. PMID:25878927

  2. Application and Program Composition of the Virtual Laminated 3 Dimensional Degenerated Element in the Bridge Structure

    YAN Xing-fei; He Shuan-hai; SUN limin

    2003-01-01

    The text include two aspects, one is the general finite element method (FEM), the other is bridge special FEM. And two viewpoints are used in it, one is the theory of FEM, the other is the practical program-making. The virtual laminated 3 dimensional degenerated element with vivid character is introduced in this paper and a large-scale computer program of FEM is manufactured. 1In addition, some current advantaged computer technology is used to make simple pre- and post processing program in order to exemplify and calculate easily in the process of researching. By using a factual example, the text also prove the method simply and resultful for analyze of bridge.

  3. Conformal Field Theory on R x S^3 from Quantized Gravity

    Hamada, Ken-ji

    2008-01-01

    Conformal algebra on R x S^3 derived from quantized gravitational fields is examined. The model we study is a renormalizable quantum theory of gravity in four dimensions described by a combined system of the Weyl action for the traceless tensor mode and the induced Wess-Zumino action managing non-perturbative dynamics of the conformal factor in the metric field. It is shown that the residual diffeomorphism invariance in the radiation^+ gauge is equal to the conformal symmetry, and the conform...

  4. Extende conformal field theories

    Taormina, A. (Chicago Univ., IL (USA). Enrico Fermi Inst.)

    1990-08-01

    Some extended conformal field theories are briefly reviewed. They illustrate how non minimal models of the Virasoro algebra (c{ge}1) can become minimal with respect to a larger algebra. The accent is put on N-extended superconformal algebras, which are relevant in superstring compactification. (orig.).

  5. Extended conformal field theories

    Taormina, Anne

    1990-08-01

    Some extended conformal field theories are briefly reviewed. They illustrate how non minimal models of the Virasoro algebra (c≥1) can become minimal with respect to a larger algebra. The accent is put on N-extended superconformal algebras, which are relevant in superstring compactification.

  6. Conformal special relativity

    It is shown that the information loss/recovery theorem based on the ADS/CFT correspondence is not consistent with the stability of the Schwarzschild or Reissner-Nordstrom black holes. Nonetheless, the conformal invariance of Yang-Mills theory points to new relativity principle compatible with quantum unitarity near those black holes

  7. Digital library conformance checklist

    Ross, Seamus; CASTELLI, Donatella; Ioannidis, Yannis; Vullo, Giuseppina; Innocenti, Perla; Candela, Leonardo; Nika, Ana; El Raheb, Katerina; Katifori, Akrivi

    2011-01-01

    This booklet is abstracted and abridged from "The Digital Library Reference Model"- D3.2 DL.org Project Deliverable. The check list is designed to verify whether or not a digital library conforms to the Digital Library Reference Model.

  8. Galilean Conformal and Superconformal Symmetries

    ,

    2011-01-01

    Firstly we discuss briefly three different algebras named as nonrelativistic (NR) conformal: Schroedinger, Galilean conformal and infinite algebra of local NR conformal isometries. Further we shall consider in some detail Galilean conformal algebra (GCA) obtained in the limit c equal to infinity from relativistic conformal algebra O(d+1,2) (d - number of space dimensions). Two different contraction limits providing GCA and some recently considered realizations will be briefly discussed. Finally by considering NR contraction of D=4 superconformal algebra the Galilei conformal superalgebra (GCSA) is obtained, in the formulation using complex Weyl supercharges.

  9. Conformal vector fields in symmetric and conformal symmetric spaces

    Ramesh Sharma

    1989-03-01

    Full Text Available Consequences of the existence of conformal vector fields in (locally symmetric and conformal symmetric spaces, have been obtained. An attempt has been made for a physical interpretation of the consequences in the framework of general relativity.

  10. To Bleed or Not to Bleed. A Prediction Based on Individual Gene Profiling Combined With Dose-Volume Histogram Shapes in Prostate Cancer Patients Undergoing Three-Dimensional Conformal Radiation Therapy

    Purpose: The main purpose of this work was to try to elucidate why, despite excellent rectal dose-volume histograms (DVHs), some patients treated for prostate cancer exhibit late rectal bleeding (LRB) and others with poor DVHs do not. Thirty-five genes involved in DNA repair/radiation response were analyzed in patients accrued in the AIROPROS 0101 trial, which investigated the correlation between LRB and dosimetric parameters. Methods and Materials: Thirty patients undergoing conformal radiotherapy with prescription doses higher than 70 Gy (minimum follow-up, 48 months) were selected: 10 patients in the low-risk group (rectal DVH with the percent volume of rectum receiving more than 70 Gy [V70Gy] 25% and V50Gy > 60%) with G2-G3 LRB, and 10 patients in the high-risk group with no toxicity. Quantitative reverse-transcriptase polymerase chain reaction was performed on RNA from lymphoblastoid cell lines obtained from Epstein-Barr virus-immortalized peripheral-blood mononucleated cells and on peripheral blood mononucleated cells. Interexpression levels were compared by using the Kruskal-Wallis test. Results: Intergroup comparison showed many constitutive differences: nine genes were significantly down-regulated in the low-risk bleeder group vs. the high-risk bleeder and high-risk nonbleeder groups: AKR1B1 (p = 0.019), BAZ1B (p = 0.042), LSM7 (p = 0.0016), MRPL23 (p = 0.015), NUDT1 (p = 0.0031), PSMB4 (p = 0.079), PSMD1 (p = 0.062), SEC22L1 (p = 0.040), and UBB (p = 0.018). Four genes were significantly upregulated in the high-risk nonbleeder group than in the other groups: DDX17 (p = 0.048), DRAP1 (p = 0.0025), RAD23 (p = 0.015), and SRF (p = 0.024). For most of these genes, it was possible to establish a cut-off value that correctly classified most patients. Conclusions: The predictive value of sensitivity and resistance to LRB of the genes identified by the study is promising and should be tested in a larger data set.

  11. Optimal set of grid size and angular increment for practical dose calculation using the dynamic conformal arc technique: a systematic evaluation of the dosimetric effects in lung stereotactic body radiation therapy

    To recommend the optimal plan parameter set of grid size and angular increment for dose calculations in treatment planning for lung stereotactic body radiation therapy (SBRT) using dynamic conformal arc therapy (DCAT) considering both accuracy and computational efficiency. Dose variations with varying grid sizes (2, 3, and 4 mm) and angular increments (2°, 4°, 6°, and 10°) were analyzed in a thorax phantom for 3 spherical target volumes and in 9 patient cases. A 2-mm grid size and 2° angular increment are assumed sufficient to serve as reference values. The dosimetric effect was evaluated using dose–volume histograms, monitor units (MUs), and dose to organs at risk (OARs) for a definite volume corresponding to the dose–volume constraint in lung SBRT. The times required for dose calculations using each parameter set were compared for clinical practicality. Larger grid sizes caused a dose increase to the structures and required higher MUs to achieve the target coverage. The discrete beam arrangements at each angular increment led to over- and under-estimated OARs doses due to the undulating dose distribution. When a 2° angular increment was used in both studies, a 4-mm grid size changed the dose variation by up to 3–4% (50 cGy) for the heart and the spinal cord, while a 3-mm grid size produced a dose difference of <1% (12 cGy) in all tested OARs. When a 3-mm grid size was employed, angular increments of 6° and 10° caused maximum dose variations of 3% (23 cGy) and 10% (61 cGy) in the spinal cord, respectively, while a 4° increment resulted in a dose difference of <1% (8 cGy) in all cases except for that of one patient. The 3-mm grid size and 4° angular increment enabled a 78% savings in computation time without making any critical sacrifices to dose accuracy. A parameter set with a 3-mm grid size and a 4° angular increment is found to be appropriate for predicting patient dose distributions with a dose difference below 1% while reducing the

  12. Transition from 2-D radiotherapy to 3-D conformal and intensity modulated radiotherapy

    Cancer is one of the leading causes of death globally and radiotherapy is currently an essential component in the management of cancer patients, either alone or in combination with surgery or chemotherapy, both for cure or palliation. It is now recognized that safe and effective radiotherapy service needs not only substantial capital investment in radiotherapy equipment and specially designed facilities but also continuous investment in maintenance and upgrading of the equipment to comply with the technical progress, but also in training the staff. The recent IAEA-TECDOC publication 'Setting up a Radiotherapy Programme: Clinical, Medical Physics, Radiation Protection and Safety Aspects' provides general guidelines for designing and implementing radiotherapy services in Member States. Advances in computer technology have enabled the possibility of transitioning from basic 2- dimensional treatment planning and delivery (2-D radiotherapy) to a more sophisticated approach with 3-dimensional conformal radiotherapy (3-D CRT). Whereas 2-D radiotherapy can be applied with simple equipment, infrastructure and training, transfer to 3-D conformal treatments requires more resources in technology, equipment, staff and training. A novel radiation treatment approach using Intensity Modulated Radiation Therapy (IMRT) that optimizes the delivery of radiation to irregularly shaped tumour volumes demands even more sophisticated equipment and seamless teamwork, and consequentially more resources, advanced training and more time for treatment planning and verification of dose delivery than 3-D CRT. Whereas 3-D CRT can be considered as a standard, IMRT is still evolving. Due to the increased interest of Member States to the modern application of radiotherapy the IAEA has received a number of requests for guidance coming from radiotherapy departments that wish to upgrade their facilities to 3-D CRT and IMRT through Technical Cooperation programme. These requests are expected to increase

  13. A Conformal Extension Theorem based on Null Conformal Geodesics

    Lübbe, Christian

    2008-01-01

    In this article we describe the formulation of null geodesics as null conformal geodesics and their description in the tractor formalism. A conformal extension theorem through an isotropic singularity is proven by requiring the boundedness of the tractor curvature and its derivatives to sufficient order along a congruence of null conformal geodesic. This article extends earlier work by Tod and Luebbe.

  14. Conformational isomerism of pyridoxal. Infrared matrix isolation and theoretical studies

    Kwiatek, Anna; Mielke, Zofia

    2015-01-01

    A combined matrix isolation FTIR and theoretical DFT/B3LYP/6-311++G(2p,2d) study of pyridoxal was performed. The calculations resulted in five stable PLHB conformers stabilized by intramolecular Osbnd H⋯O bonding between phenolic OH and carbonyl Cdbnd O groups and another thirteen conformers in which OH or/and aldehyde groups are rotated by 180° around CO or/and CC bonds leading, respectively, to formation of PLO, PLA and PLOA conformers. The analysis of the spectra of the as-deposited matrix indicated that two most stable PLHB1 and PLHB2 conformers with intramolecular hydrogen bond are present in the matrix. The exposure of the PL/Ar matrix to mercury lamp radiation (λ > 345 nm) induced conformational change of PLHB isomers to PLOA ones.

  15. Dosimetry study on conformal radiation therapy, intensity modulated radiation therapy and intensity modulated arc radiotherapy in middle thoracic esophageal cancer%胸中段食管癌三维适形放疗、调强放疗及旋转调强放疗的剂量学研究

    孙尧; 刘希军; 刘同海; 于甬华; 尹勇

    2013-01-01

    Objective To compare the dosimetry of three different radiation therapy plans [threedimensional conformal radiation therapy (3DCRT),intensity modulated radiation therapy (IMRT),intensity modulated arc radiotherapy (IMAT)].Methods Selected 15 cases with middle thoracic esophageal cancer,Varian Eclipse 8.6 planning systems were designed with 3DCRT,IMRT,IMAT,3DCRT using 5-8 coplanar radiation fields,IMRT using 7 coplanar radiation fields,IMAT using 2 radians.Three planned dose difference were compared.Results Compared with 3DCRT,IMRT and IMAT were better with heterogeneity index (HI),conformality index (CI),VPTV 95 %,V5,V20,V35 of total lung,and V30 of heart (t =2.531,P< 0.05).There was no statistically significant difference for the V10,V15,V25,V30 mean dose of total lung,the mean dose of heart,the maximum dose of spinal cord,and the minimum dose of PTV among the three plans (t =1.325,P >0.05).Conclusion IMAT and IMRT are similar in the middle thoracic esophageal cancer radiotherapy target volume dose coverage and organs at risk protection,they are better than 3DCRT.IMAT in the monitor units and delivery time are less than IMRT.%目的 研究胸中段食管癌三维适形放疗(3DCRT)、调强放疗(IMRT)、旋转调强放疗(IMAT)3种放疗计划的剂量差异.方法 选取胸中段食管癌患者15例,以Varian Eclipse 8.6计划系统分别设计3DCRT、IMRT、IMAT 3种放疗计划,其中3DCRT采用5~8个共面射野,IMRT采用7个共面射野,IMAT采用2个弧度.比较3种计划的剂量学差异.结果 IMRT、IMRT的靶区均匀指数(HI)、适形指数(CI)、95%计划靶体积(PTV)体积剂量均优于3DCRT,全肺V5、V20、V35、心脏V30受照剂量低于3DCRT(t=2.531,P< 0.05),而在全肺V10、V15、V25、V30、全肺平均、心脏平均、脊髓Dmax剂量之间三者的差异均无统计学意义(t=1.325,P>0.05).结论 IMAT与IMRT在胸中段食管癌放疗靶区体积剂量覆盖和危及器官保护方面相似,二者均优于3DCRT.IMAT

  16. Hot Conformal Gauge Theories

    Mojaza, Matin; Pica, Claudio; Sannino, Francesco

    2010-01-01

    We compute the nonzero temperature free energy up to the order g^6 \\ln(1/g) in the coupling constant for vector like SU(N) gauge theories featuring matter transforming according to different representations of the underlying gauge group. The number of matter fields, i.e. flavors, is arranged in...... such a way that the theory develops a perturbative stable infrared fixed point at zero temperature. Due to large distance conformality we trade the coupling constant with its fixed point value and define a reduced free energy which depends only on the number of flavors, colors and matter representation....... We show that the reduced free energy changes sign, at the second, fifth and sixth order in the coupling, when decreasing the number of flavors from the upper end of the conformal window. If the change in sign is interpreted as signal of an instability of the system then we infer a critical number of...

  17. Conformational flexibility of aspartame.

    Toniolo, Claudio; Temussi, Pierandrea

    2016-05-01

    L-Aspartyl-L-phenylalanine methyl ester, better known as aspartame, is not only one of the most used artificial sweeteners, but also a very interesting molecule with respect to the correlation between molecular structure and taste. The extreme conformational flexibility of this dipeptide posed a huge difficulty when researchers tried to use it as a lead compound to design new sweeteners. In particular, it was difficult to take advantage of its molecular model as a mold to infer the shape of the, then unknown, active site of the sweet taste receptor. Here, we follow the story of the 3D structural aspects of aspartame from early conformational studies to recent docking into homology models of the receptor. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 376-384, 2016. PMID:27038223

  18. Conformal scalar field wormholes

    Halliwell, Jonathan J.; Laflamme, Raymond

    1989-01-01

    The Euclidian Einstein equations with a cosmological constant and a conformally coupled scalar field are solved, taking the metric to be of the Robertson-Walker type. In the case Lambda = 0, solutions are found which represent a wormhole connecting two asymptotically flat Euclidian regions. In the case Lambda greater than 0, the solutions represent tunneling from a small Tolman-like universe to a large Robertson-Walker universe.

  19. Conformable light emitting modules

    Jablonski, Michal

    2014-01-01

    As we become increasingly aware that there is more to light than the image it forms on our retina, and as we become more environmentally aware, the value of non-image-forming light increases along with the need for various new light related appliances. In particular, some lighting related applications are emerging which demand conformability (flexibility and stretchability). Well-being, automotive or wearable electronic applications are just a few examples where these trends can be observed. ...

  20. The conformal bootstrap

    Poland, David; Simmons-Duffin, David

    2016-06-01

    The conformal bootstrap was proposed in the 1970s as a strategy for calculating the properties of second-order phase transitions. After spectacular success elucidating two-dimensional systems, little progress was made on systems in higher dimensions until a recent renaissance beginning in 2008. We report on some of the main results and ideas from this renaissance, focusing on new determinations of critical exponents and correlation functions in the three-dimensional Ising and O(N) models.

  1. Evaluation of conformal integrals

    Bzowski, Adam; Skenderis, Kostas

    2015-01-01

    We present a comprehensive method for the evaluation of a vast class of integrals representing 3-point functions of conformal field theories in momentum space. The method leads to analytic, closed-form expressions for all scalar and tensorial 3-point functions of operators with integer dimensions in any spacetime dimension. In particular, this encompasses all 3-point functions of the stress tensor, conserved currents and marginal scalar operators.

  2. Intensity-Modulated vs. Conformal Radiotherapy of Parotid Gland Tumors: Potential Impact on Hearing Loss

    In 3-dimensional (3D) conformal radiotherapy of parotid gland tumors, little effort is made to avoid the auditory system or the oral cavity. Damage may occur when the ear is located inside the treatment field. The purpose of this study was to design and evaluate an intensity-modulation radiotherapy (IMRT) class solution, and to compare this technique to a 3D conformal approach with respect to hearing loss. Twenty patients with parotid gland cancer were retrospectively planned with 2 different techniques using the original planning target volume (PTV). First, a conventional technique using a wedged beam pair was applied, yielding a dose distribution conformal to the shape of the PTV. Next, an IMRT technique using a fluence map optimization with predefined constraints was designed. A dose of 66 Gy in the PTV was given at the International Commission on Radiation Units and Measures (ICRU) dose prescription point. Dose-volume histograms of the PTV and organs at risk (OARs), such as auditory system, oral cavity, and spinal cord, were compared. The dose in the OARs was lower in the IMRT plans. The mean volume of the middle ear receiving a dose higher than 50 Gy decreased from 66.5% to 33.4%. The mean dose in the oral cavity decreased from 19.4 Gy to 16.6 Gy. The auditory system can be spared if the distance between the inner ear and the PTV is 0.6 cm or larger, and if the overlap between the middle ear and the PTV is smaller than 10%. The maximum dose in the spinal cord was below 40 Gy in all treatment plans. The mean volume of the PTV receiving less than 95% of the prescribed dose increased in the IMRT plan slightly from 3.3% to 4.3 % (p = 0.01). The mean volume receiving more than 107% increased from 0.9% to 2.5% (p = 0.02). It can be concluded that the auditory system, as well as the oral cavity, can be spared with IMRT, but at the cost of a slightly larger dose inhomogeneity in the PTV. The IMRT technique can therefore, in most cases, be recommended as the treatment

  3. Comparison of 3-dimensional proton-photon dose distribution and evaluation of side effects after radiotherapy

    Poljanc, K

    2000-01-01

    The use of high precision radiation with particles (protons and ions) allows the radiation of tumors near risk organs and immedicable tumors. The aim of this work is the comparison between normal tissue complication probability for craniocerebral tumors of children and youth during simulation of photontherapy and proton therapy. The multivariate analysis gives the possibility to determine the tolerance dose for certain organs.

  4. Random Conformal Weldings

    Astala, K; Kupiainen, A; Saksman, E

    2009-01-01

    We construct a conformally invariant random family of closed curves in the plane by welding of random homeomorphisms of the unit circle. The homeomorphism is constructed using the exponential of $\\beta X$ where $X$ is the restriction of the two dimensional free field on the circle and the parameter $\\beta$ is in the "high temperature" regime $\\beta<\\sqrt 2$. The welding problem is solved by studying a non-uniformly elliptic Beltrami equation with a random complex dilatation. For the existence a method of Lehto is used. This requires sharp probabilistic estimates to control conformal moduli of annuli and they are proven by decomposing the free field as a sum of independent fixed scale fields and controlling the correlations of the complex dilation restricted to dyadic cells of various scales. For uniqueness we invoke a result by Jones and Smirnov on conformal removability of H\\"older curves. We conjecture that our curves are locally related to SLE$(\\kappa)$ for $\\kappa<4$.

  5. Phase-compensated metasurface for a conformal microwave antenna

    Germain, Dylan; Seetharamdoo, Divitha; Burokur, Shah Nawaz; De Lustrac, André

    2013-01-01

    The in-phase radiation from a conformal metamaterial surface is numerically and experimentally reported. The LC-resonant metasurface is composed of a simultaneously capacitive and an inductive grid constituted by copper strips printed on both sides of a dielectric board. The metasurface is designed to fit a curved surface by modifying its local phase. The latter phase-compensated metasurface is used as a reflector in a conformal Fabry-Pérot resonant cavity designed to operate at microwave fre...

  6. Bioactive glass-poly (ε-caprolactone) composite scaffolds with 3 dimensionally hierarchical pore networks

    Hierarchically mesoporous-macroporous-giant-porous bioactive glass/poly ε-caprolactone (PCL) composite scaffolds were prepared using a combination of the sol-gel method, evaporation-induced self-assembly process in the presence of nonionic triblock copolymer, EO100PO65EO100 (F127), as template, salt leaching method, and rapid prototyping techniques. F127 acts as a template, inducing the formation of mesopores, NaCl with sizes between 25 and 33 μm provides macro-pores after leaching, and rapid prototyping produces giant-pores. The structure and morphology of the scaffolds were characterized by the field emission scanning electron microscopy, transmission electron microscopy, and Hg porosimetry. The mechanical properties of the scaffolds were examined by the dynamic mechanical analysis. Their in vitro bioactivities were confirmed by immersing the scaffolds in simulated body fluid. Their biocompatibilities were also evaluated by culturing human bone marrow stromal cells on the scaffolds. The scaffolds show good molding capabilities, mechanical properties, 3 dimensionally well-interconnected pore structures, bioactivities, and biocompatibilities in vitro. Depending on the amount of NaCl, the scaffolds also show unique sponge-like properties, but still retain better mechanical properties than general salt leaching derived PCL scaffolds. All of the data provide good evidence that the obtained scaffolds possess excellent potential for applications in the fields of tissue engineering and drug storage.

  7. Research on the method of cavitations resistance in a piezoelectric pump with 3-dimensional mesh structure

    ZHANG Jian-hui; XIA Qi-xiao; Bai Heng-jun; NING Hong-gang; ONUKI Akiyoshi

    2006-01-01

    The volume valve piezoelectric pump has received increasing attention from many areas because of its different characteristics such as the absence of chemical pollution and electromagnetic pollution.However,when the pump is working,it produces cavitations and the air bubbles that originate from these will flow out of the pump.Cavitations occurring in the pump will bring out noise and shorten the life of the pump.Furthermore,air bubbles flowing out of the pump will hinder its application in areas such as medical treatment and health care where blood transfusion and infusion are concerned.As a solution to this disadvantage,the CR3DMS (cavitations resistance with 3-dimensional mesh structure) method is developed,which is tested and verified to be effective on not only reducing the occurrence of cavitations and eliminating cavitations' flowing out,but also restraining the emission of noise.In conclusion,the pump with CR3DMS,on the relationship between flow and driving frequency and the relationship between flow and the number of Resistant-Layers in both theory and test,are analyzed.

  8. A Novel Method of Orbital Floor Reconstruction Using Virtual Planning, 3-Dimensional Printing, and Autologous Bone.

    Vehmeijer, Maarten; van Eijnatten, Maureen; Liberton, Niels; Wolff, Jan

    2016-08-01

    Fractures of the orbital floor are often a result of traffic accidents or interpersonal violence. To date, numerous materials and methods have been used to reconstruct the orbital floor. However, simple and cost-effective 3-dimensional (3D) printing technologies for the treatment of orbital floor fractures are still sought. This study describes a simple, precise, cost-effective method of treating orbital fractures using 3D printing technologies in combination with autologous bone. Enophthalmos and diplopia developed in a 64-year-old female patient with an orbital floor fracture. A virtual 3D model of the fracture site was generated from computed tomography images of the patient. The fracture was virtually closed using spline interpolation. Furthermore, a virtual individualized mold of the defect site was created, which was manufactured using an inkjet printer. The tangible mold was subsequently used during surgery to sculpture an individualized autologous orbital floor implant. Virtual reconstruction of the orbital floor and the resulting mold enhanced the overall accuracy and efficiency of the surgical procedure. The sculptured autologous orbital floor implant showed an excellent fit in vivo. The combination of virtual planning and 3D printing offers an accurate and cost-effective treatment method for orbital floor fractures. PMID:27137437

  9. Optimal iodine dose for 3-dimensional multidetector-row CT angiography of the liver

    Purpose: To clarify the optimal iodine dose of contrast material for 3-dimensional multidetector-row CT angiography (3D-MDCTA) of the venous vasculature of the liver using volume rendering technique. Materials and methods: This study included 103 patients who were randomly assigned to 5 contrast-enhanced MDCT protocol groups with different body-weight-tailored doses of contrast material: 500, 600, 630, 650, and 700 mgI/kg body weight. The arterial, portal, and hepatic parenchymal phases were obtained to evaluate enhancement values of the aorta, portal vein, and hepatic vein. Visualization of the portal and hepatic veins on the volume-rendering images of 3D-MDCTA was evaluated using a 5-point grade. Dunnett's test was used to compare the mean enhancement value and mean grades of image quality (700 mgI/kg dose group was control). Results: The mean enhancement values of portal and hepatic vein in the group with 500 and 600 mgI/kg were significantly lower than those of the control group. During visual assessment, a significantly lower mean grades were observed in 500 mgI/kg groups for the portal vein, and 500 and 600 mgI/kg groups for hepatic vein. There were no significant intergroup differences in mean enhancement values and visual assessment among the groups using 630 mgI/kg or more. Conclusion: Iodine doses of 630 mgI/kg was recommended for 3D-MDCTA

  10. 3-DIMENSIONAL Numerical Modeling on the Combustion and Emission Characteristics of Biodiesel in Diesel Engines

    Yang, Wenming; An, Hui; Amin, Maghbouli; Li, Jing

    2014-11-01

    A 3-dimensional computational fluid dynamics modeling is conducted on a direct injection diesel engine fueled by biodiesel using multi-dimensional software KIVA4 coupled with CHEMKIN. To accurately predict the oxidation of saturated and unsaturated agents of the biodiesel fuel, a multicomponent advanced combustion model consisting of 69 species and 204 reactions combined with detailed oxidation pathways of methyl decenoate (C11H22O2), methyl-9-decenoate (C11H20O2) and n-heptane (C7H16) is employed in this work. In order to better represent the real fuel properties, the detailed chemical and thermo-physical properties of biodiesel such as vapor pressure, latent heat of vaporization, liquid viscosity and surface tension were calculated and compiled into the KIVA4 fuel library. The nitrogen monoxide (NO) and carbon monoxide (CO) formation mechanisms were also embedded. After validating the numerical simulation model by comparing the in-cylinder pressure and heat release rate curves with experimental results, further studies have been carried out to investigate the effect of combustion chamber design on flow field, subsequently on the combustion process and performance of diesel engine fueled by biodiesel. Research has also been done to investigate the impact of fuel injector location on the performance and emissions formation of diesel engine.

  11. Automated image analysis reveals the dynamic 3-dimensional organization of multi-ciliary arrays

    Domenico F. Galati

    2016-01-01

    Full Text Available Multi-ciliated cells (MCCs use polarized fields of undulating cilia (ciliary array to produce fluid flow that is essential for many biological processes. Cilia are positioned by microtubule scaffolds called basal bodies (BBs that are arranged within a spatially complex 3-dimensional geometry (3D. Here, we develop a robust and automated computational image analysis routine to quantify 3D BB organization in the ciliate, Tetrahymena thermophila. Using this routine, we generate the first morphologically constrained 3D reconstructions of Tetrahymena cells and elucidate rules that govern the kinetics of MCC organization. We demonstrate the interplay between BB duplication and cell size expansion through the cell cycle. In mutant cells, we identify a potential BB surveillance mechanism that balances large gaps in BB spacing by increasing the frequency of closely spaced BBs in other regions of the cell. Finally, by taking advantage of a mutant predisposed to BB disorganization, we locate the spatial domains that are most prone to disorganization by environmental stimuli. Collectively, our analyses reveal the importance of quantitative image analysis to understand the principles that guide the 3D organization of MCCs.

  12. Immediate 3-dimensional ridge augmentation after extraction of periodontally hopeless tooth using chinblock graft

    Desai, Ankit; Thomas, Raison; A. Baron, Tarunkumar; Shah, Rucha; Mehta, Dhoom-Singh

    2015-01-01

    Background The aim of the present study was to evaluate clinically and radiographically, the efficacy of immediate ridge augmentation to reconstruct the vertical and horizontal dimensions at extraction sites of periodontally hopeless tooth using an autogenous chin block graft. Material and Methods A total of 11 patients (7 male & 4 female) with localized advanced bone loss around single rooted teeth having hopeless prognosis and indicated for extraction were selected for the study. The teeth were atraumatically extracted and deficient sites were augmented using autogenous chin block graft. Parameters like clinically soft tissue height - width and also radiographic ridge height -width were measured before and 6 months after augmentation. Obtained results were tabulated and analysed statistically. Results After 6 months of immediate ridge augmentation, the mean gain in radiographic vertical height and horizontal width was 7.64 + 1.47 mm (P = 0.005) and 5.28 + 0.46 mm (P = 0.007) respectively which was found to be statistically significant (P extraction site. It can provide adequate hard and soft tissue foundation for perfect 3-Dimensional prosthetic positioning of implant in severely deficient ridges. Key words:Immediate ridge augmentation, periondontally hopeless tooth, autogenous chin graft, dental implant. PMID:26644832

  13. Casting of 3-dimensional footwear prints in snow with foam blocks.

    Petraco, Nicholas; Sherman, Hal; Dumitra, Aurora; Roberts, Marcel

    2016-06-01

    Commercially available foam blocks are presented as an alternative material for the casting and preservation of 3-dimensional footwear impressions located in snow. The method generates highly detailed foam casts of questioned footwear impressions. These casts can be compared to the known outsole standards made from the suspects' footwear. Modification of the commercially available foam casting blocks is simple and fast. The foam block is removed and a piece of cardboard is secured to one side of the block with painter's masking tape. The prepared foam block is then placed back into its original box, marked appropriately, closed and stored until needed. When required the foam block is carefully removed from its storage box and gently placed, foam side down, over the questioned footwear impression. Next, the crime scene technician's hands are placed on top of the cardboard and pressure is gently applied by firmly pressing down onto the impression. The foam cast is removed, dried and placed back into its original container and sealed. The resulting 3D impressions can be directly compared to the outsole of known suspected item(s) of footwear. PMID:27124876

  14. An experimental study for qualitatively diagnosing stapes lesions by helical 3-dimensional CT

    Kawaue, Akifumi; Kuki, Kiyonori; Yamanaka, Noboru [Wakayama Medical Univ., Wakayama (Japan); Nishimura, Michihiko

    2001-08-01

    To evaluate qualitative diagnosis of stapes lesions by 3-dimensional computed tomography (3D-CT) combined with superselective image processing (3D-SS) of stapes, we studied helical 3D-CT on a phantom model of the temporal bone. Two stapes models were used-1 made from the bone filler, Celatite, consistent in bone density but changing in cross sectional area, and the other made from an apacerum rod used in quantitative computed tomography (QCT), consistent in cross sectional area but changing in bone density. These stapes models were put into a skull phantom and analyzed by helical 3D-CT. The influence of the tympanic cavity conditions on CT images of stapes was evaluated by filling the phantom model with Vaseline following 3D selective reconstruction. In all stapes models, lowering the lower CT window width threshold resulted in an enlarged cross-sectional area of the model. The higher the bone density, the lower the increase in cross-sectional area in the image. The stapes model with lower density had greater influence on the imaging by tympanic cavity conditions and was likely to be misdiagnosed as showing higher bone density. Based on the experimental study, 3D-SS by helical 3D-CT appears to be a useful measure for qualitatively diagnosing stapes lesions. (author)

  15. Development of a 3-Dimensional Dosimetry System for Leksell Gamma Knife-Perfexion

    Yoon, KyoungJun; Lee, DoHeui; Cho, ByungChul; Lee, SangWook; Ahn, SeungDo

    2015-01-01

    The purpose of our study is to develop a new, 3-dimensional dosimetry system to verify the accuracy of dose deliveries in Leksell Gamma Knife-Perfexion TM (LGKP) (Elekta, Norcross, GA, USA). The instrument consists of a moving head phantom, an embedded thin active layer and a CCD camera system and was designed to be mounted to LGKP. As an active material concentrically located in the hemispheric head phantom, we choose Gafchromic EBT3 films and Gd2O2S;Tb phosphor sheets for dosimetric measurements. Also, to compensate the lack of backscatter, we located a 1 cm thick PMMA plate downstream of the active layer. The PMMA plate was transparent for scintillation lights to reach the CCD with 1200x1200 pixels by a 5.2 um pitch. Using this system, three hundred images by a 0.2 mm slice gap were acquired under each of three collimator setups, i.e. 4 mm, 8 mm, and 16 mm, respectively. The 2D projected images taken by CCD camera were compared with the dose distributions measured by EBT3 films in the same conditions. All ...

  16. Gravity-sensitive signaling drives 3-dimensional formation of multicellular thyroid cancer spheroids.

    Grosse, Jirka; Wehland, Markus; Pietsch, Jessica; Schulz, Herbert; Saar, Katrin; Hübner, Norbert; Eilles, Christoph; Bauer, Johann; Abou-El-Ardat, Khalil; Baatout, Sarah; Ma, Xiao; Infanger, Manfred; Hemmersbach, Ruth; Grimm, Daniela

    2012-12-01

    This study focused on the effects induced by a random positioning machine (RPM) on FTC-133 thyroid cancer cells and evaluated signaling elements involved in 3-dimensional multicellular tumor spheroid (MCTS) formation. The cells were cultured on the RPM, a device developed to simulate microgravity, and under static 1-g conditions. After 24 h on the RPM, MCTSs swimming in culture supernatants were found, in addition to growth of adherent (AD) cells. Cells grown on the RPM showed higher levels of NF-κB p65 protein and apoptosis than 1-g controls, a result also found earlier in endothelial cells. Employing microarray analysis, we found 487 significantly regulated transcripts belonging not only to the apoptosis pathway but also to other biological processes. Selected transcripts were analyzed with quantitative real-time PCR using the same samples. Compared with 1-g IL-6, IL-8, CD44, and OPN were significantly up-regulated in AD cells but not in MCTSs, while ERK1/2, CAV2, TLN1, and CTGF were significantly down-regulated in AD cells. Simultaneously, the expression of ERK2, IL-6, CAV2, TLN1, and CTGF was reduced in MCTSs. IL-6 protein expression and secretion mirrored its gene expression. Thus, we concluded that the signaling elements IL-6, IL-8, OPN, TLN1, and CTGF are involved with NF-κB p65 in RPM-dependent thyroid carcinoma cell spheroid formation. PMID:22964303

  17. Embedding and publishing interactive, 3-dimensional, scientific figures in Portable Document Format (PDF files.

    David G Barnes

    Full Text Available With the latest release of the S2PLOT graphics library, embedding interactive, 3-dimensional (3-d scientific figures in Adobe Portable Document Format (PDF files is simple, and can be accomplished without commercial software. In this paper, we motivate the need for embedding 3-d figures in scholarly articles. We explain how 3-d figures can be created using the S2PLOT graphics library, exported to Product Representation Compact (PRC format, and included as fully interactive, 3-d figures in PDF files using the movie15 LaTeX package. We present new examples of 3-d PDF figures, explain how they have been made, validate them, and comment on their advantages over traditional, static 2-dimensional (2-d figures. With the judicious use of 3-d rather than 2-d figures, scientists can now publish, share and archive more useful, flexible and faithful representations of their study outcomes. The article you are reading does not have embedded 3-d figures. The full paper, with embedded 3-d figures, is recommended and is available as a supplementary download from PLoS ONE (File S2.

  18. Conformal Janus on Euclidean Sphere

    Bak, Dongsu; Rey, Soo-Jong

    2016-01-01

    We interpret Janus as an interface in a conformal field theory and study its properties. The Janus is created by an exactly marginal operator and we study its effect on the interface conformal field theory on the Janus. We do this by utilizing the AdS/CFT correspondence. We compute the interface free energy both from leading correction to the Euclidean action in the dual gravity description and from conformal perturbation theory in the conformal field theory. We find that the two results agree each other and that the interface free energy scales precisely as expected from the conformal invariance of the Janus interface.

  19. Metric-torsional conformal gravity

    When in general geometric backgrounds the metric is accompanied by torsion, the metric conformal properties should correspondingly be followed by analogous torsional conformal properties; however a combined metric torsional conformal structure has never been found which provides a curvature that is both containing metric-torsional degree of freedom and conformally invariant: in this Letter we construct such a metric-torsional conformal curvature. We proceed by building the most general action, then deriving the most general system of field equations; we check their consistency by showing that both conservation laws and trace condition are verified. Final considerations and comments are outlined.

  20. Conformal superalgebras via tractor calculus

    Lischewski, Andree

    2015-01-01

    We use the manifestly conformally invariant description of a Lorentzian conformal structure in terms of a parabolic Cartan geometry in order to introduce a superalgebra structure on the space of twistor spinors and normal conformal vector fields formulated in purely algebraic terms on parallel sections in tractor bundles. Via a fixed metric in the conformal class, one reproduces a conformal superalgebra structure that has been considered in the literature before. The tractor approach, however, makes clear that the failure of this object to be a Lie superalgebra in certain cases is due to purely algebraic identities on the spinor module and to special properties of the conformal holonomy representation. Moreover, it naturally generalizes to higher signatures. This yields new formulas for constructing new twistor spinors and higher order normal conformal Killing forms out of existing ones, generalizing the well-known spinorial Lie derivative. Moreover, we derive restrictions on the possible dimension of the space of twistor spinors in any metric signature.

  1. Conformal superalgebras via tractor calculus

    We use the manifestly conformally invariant description of a Lorentzian conformal structure in terms of a parabolic Cartan geometry in order to introduce a superalgebra structure on the space of twistor spinors and normal conformal vector fields formulated in purely algebraic terms on parallel sections in tractor bundles. Via a fixed metric in the conformal class, one reproduces a conformal superalgebra structure that has been considered in the literature before. The tractor approach, however, makes clear that the failure of this object to be a Lie superalgebra in certain cases is due to purely algebraic identities on the spinor module and to special properties of the conformal holonomy representation. Moreover, it naturally generalizes to higher signatures. This yields new formulas for constructing new twistor spinors and higher order normal conformal Killing forms out of existing ones, generalizing the well-known spinorial Lie derivative. Moreover, we derive restrictions on the possible dimension of the space of twistor spinors in any metric signature. (paper)

  2. The evolution of rectal and urinary toxicity and immune response in prostate cancer patients treated with two three-dimensional conformal radiotherapy techniques

    Vránová, J.; Vinakurau, S.; Richter, J.; Starec, M.; Fišerová, Anna; Rosina, J.

    2011-01-01

    Roč. 2, č. 6 (2011), s. 1-13. ISSN 1748-717X R&D Projects: GA AV ČR IAA500200620 Institutional research plan: CEZ:AV0Z50200510 Keywords : 3-dimensional conformal radiotherapy (3DCRT) * gastrointestinal and genitourinary toxicity * prostate cancer Subject RIV: EC - Immunology Impact factor: 2.321, year: 2011

  3. Radiation Therapy Planning for Early-Stage Hodgkin Lymphoma: Experience of the International Lymphoma Radiation Oncology Group

    Maraldo, Maja V., E-mail: dra.maraldo@gmail.com [Departments of Clinical Oncology and Hematology, Rigshospitalet, University of Copenhagen (Denmark); Dabaja, Bouthaina S. [Department of Radiation Oncology, MD Anderson Cancer Center, Texas (United States); Filippi, Andrea R. [Department of Oncology, University of Torino School of Medicine, Torino (Italy); Illidge, Tim [Department of Oncology, Christie Hospital, Manchester (United Kingdom); Tsang, Richard [Department of Radiation Oncology, Princess Margaret Cancer Centre, Toronto, Ontario (Canada); Ricardi, Umberto [Department of Oncology, University of Torino School of Medicine, Torino (Italy); Petersen, Peter M.; Schut, Deborah A. [Departments of Clinical Oncology and Hematology, Rigshospitalet, University of Copenhagen (Denmark); Garcia, John [Department of Radiation Oncology, MD Anderson Cancer Center, Texas (United States); Headley, Jayne [Department of Oncology, Christie Hospital, Manchester (United Kingdom); Parent, Amy; Guibord, Benoit [Department of Radiation Oncology, Princess Margaret Cancer Centre, Toronto, Ontario (Canada); Ragona, Riccardo [Department of Oncology, University of Torino School of Medicine, Torino (Italy); Specht, Lena [Departments of Clinical Oncology and Hematology, Rigshospitalet, University of Copenhagen (Denmark)

    2015-05-01

    Purpose: Early-stage Hodgkin lymphoma (HL) is a rare disease, and the location of lymphoma varies considerably between patients. Here, we evaluate the variability of radiation therapy (RT) plans among 5 International Lymphoma Radiation Oncology Group (ILROG) centers with regard to beam arrangements, planning parameters, and estimated doses to the critical organs at risk (OARs). Methods: Ten patients with stage I-II classic HL with masses of different sizes and locations were selected. On the basis of the clinical information, 5 ILROG centers were asked to create RT plans to a prescribed dose of 30.6 Gy. A postchemotherapy computed tomography scan with precontoured clinical target volume (CTV) and OARs was provided for each patient. The treatment technique and planning methods were chosen according to each center's best practice in 2013. Results: Seven patients had mediastinal disease, 2 had axillary disease, and 1 had disease in the neck only. The median age at diagnosis was 34 years (range, 21-74 years), and 5 patients were male. Of the resulting 50 treatment plans, 15 were planned with volumetric modulated arc therapy (1-4 arcs), 16 with intensity modulated RT (3-9 fields), and 19 with 3-dimensional conformal RT (2-4 fields). The variations in CTV-to-planning target volume margins (5-15 mm), maximum tolerated dose (31.4-40 Gy), and plan conformity (conformity index 0-3.6) were significant. However, estimated doses to OARs were comparable between centers for each patient. Conclusions: RT planning for HL is challenging because of the heterogeneity in size and location of disease and, additionally, to the variation in choice of treatment techniques and field arrangements. Adopting ILROG guidelines and implementing universal dose objectives could further standardize treatment techniques and contribute to lowering the dose to the surrounding OARs.

  4. Radiation Therapy Planning for Early-Stage Hodgkin Lymphoma: Experience of the International Lymphoma Radiation Oncology Group

    Purpose: Early-stage Hodgkin lymphoma (HL) is a rare disease, and the location of lymphoma varies considerably between patients. Here, we evaluate the variability of radiation therapy (RT) plans among 5 International Lymphoma Radiation Oncology Group (ILROG) centers with regard to beam arrangements, planning parameters, and estimated doses to the critical organs at risk (OARs). Methods: Ten patients with stage I-II classic HL with masses of different sizes and locations were selected. On the basis of the clinical information, 5 ILROG centers were asked to create RT plans to a prescribed dose of 30.6 Gy. A postchemotherapy computed tomography scan with precontoured clinical target volume (CTV) and OARs was provided for each patient. The treatment technique and planning methods were chosen according to each center's best practice in 2013. Results: Seven patients had mediastinal disease, 2 had axillary disease, and 1 had disease in the neck only. The median age at diagnosis was 34 years (range, 21-74 years), and 5 patients were male. Of the resulting 50 treatment plans, 15 were planned with volumetric modulated arc therapy (1-4 arcs), 16 with intensity modulated RT (3-9 fields), and 19 with 3-dimensional conformal RT (2-4 fields). The variations in CTV-to-planning target volume margins (5-15 mm), maximum tolerated dose (31.4-40 Gy), and plan conformity (conformity index 0-3.6) were significant. However, estimated doses to OARs were comparable between centers for each patient. Conclusions: RT planning for HL is challenging because of the heterogeneity in size and location of disease and, additionally, to the variation in choice of treatment techniques and field arrangements. Adopting ILROG guidelines and implementing universal dose objectives could further standardize treatment techniques and contribute to lowering the dose to the surrounding OARs

  5. Metamaterials with conformational nonlinearity

    Lapine, Mikhail; Shadrivov, Ilya V.; Powell, David A.; Kivshar, Yuri S.

    2011-11-01

    Within a decade of fruitful development, metamaterials became a prominent area of research, bridging theoretical and applied electrodynamics, electrical engineering and material science. Being man-made structures, metamaterials offer a particularly useful playground to develop interdisciplinary concepts. Here we demonstrate a novel principle in metamaterial assembly which integrates electromagnetic, mechanical, and thermal responses within their elements. Through these mechanisms, the conformation of the meta-molecules changes, providing a dual mechanism for nonlinearity and offering nonlinear chirality. Our proposal opens a wide road towards further developments of nonlinear metamaterials and photonic structures, adding extra flexibility to their design and control.

  6. Quantified Facial Soft-tissue Strain in Animation Measured by Real-time Dynamic 3-Dimensional Imaging

    Vivian M. Hsu, MD

    2014-09-01

    Conclusions: This pilot study illustrates that the face can be objectively and quantitatively evaluated using dynamic major strain analysis. The technology of 3-dimensional optical imaging can be used to advance our understanding of facial soft-tissue dynamics and the effects of animation on facial strain over time.

  7. Characterization of the 3-dimensional microstructure of a graphite negative electrode from a Li-ion battery

    Shearing, P.R.; Howard, L.E.; Jørgensen, Peter Stanley; Brandon, N.P.; Harris, S.J.

    2010-01-01

    The 3-dimensional microstructure of a porous electrode from a lithium-ion battery has been characterized for the first time. We use X-ray tomography to reconstruct a 43 × 348 × 478 μm sample volume with voxel dimensions of 480 nm, subsequent division of the reconstructed volumes into sub-volumes of...

  8. The accuracy of reformatted images using a new virtual 3-dimensional dental implant system

    Choi, Jin Seok; Kim, Eun Kyung; Han, Won Jeong [Dankook University College of Medicine, Seoul (Korea, Republic of)

    2003-09-15

    To compare the measurements of the mandible and the detectability of the mandibular canal on reformatted images using a newly developed 3-dimensional implant simulation program with traditionally used CT multiplanar reconstruction program and true measurements. Ten dry dog mandibles were used in this study. Occlusal templates for CT examination were fabricated and marked with gutta percha at ten sites. Axial CT scans were taken and reconstructed using DentaScan (D group) and Vimplant program (V group), and each mandible was sectioned at the previously marked sites (R group). Maximum vertical height (H) and maximum width (W) of the mandible, the distances from buccal border of the mandibular canal to the most buccal aspect of the mandible (X), and the distance from the superior border of the mandibular canal to the alveolar crest (Y) were measured, and the mandibular measurements in each group were compared. Detectability of mandibular canal was evaluated using a 3-point scale in both V and D groups by three oral radiologists and compared. H in the V group was slightly greater than that in the D group, and W and X in the V group was slightly less than those in the D group. H in the V group was less than that in the R group, and W and X in the V group was larger than those in the R group. The detectability of the mandibular canal did not show statistically significant differences between V and D groups. The results of the experiment show that the newly developed, inexpensive Vimplant simulation program can be used as an alternative to the traditionally used, and more expensive CT multiplanar reconstruction program.

  9. A customized bolus produced using a 3-dimensional printer for radiotherapy.

    Shin-Wook Kim

    Full Text Available OBJECTIVE: Boluses are used in high-energy radiotherapy in order to overcome the skin sparing effect. In practice though, commonly used flat boluses fail to make a perfect contact with the irregular surface of the patient's skin, resulting in air gaps. Hence, we fabricated a customized bolus using a 3-dimensional (3D printer and evaluated its feasibility for radiotherapy. METHODS: We designed two kinds of bolus for production on a 3D printer, one of which was the 3D printed flat bolus for the Blue water phantom and the other was a 3D printed customized bolus for the RANDO phantom. The 3D printed flat bolus was fabricated to verify its physical quality. The resulting 3D printed flat bolus was evaluated by assessing dosimetric parameters such as D1.5 cm, D5 cm, and D10 cm. The 3D printed customized bolus was then fabricated, and its quality and clinical feasibility were evaluated by visual inspection and by assessing dosimetric parameters such as Dmax, Dmin, Dmean, D90%, and V90%. RESULTS: The dosimetric parameters of the resulting 3D printed flat bolus showed that it was a useful dose escalating material, equivalent to a commercially available flat bolus. Analysis of the dosimetric parameters of the 3D printed customized bolus demonstrated that it is provided good dose escalation and good contact with the irregular surface of the RANDO phantom. CONCLUSIONS: A customized bolus produced using a 3D printer could potentially replace commercially available flat boluses.

  10. Albedo and heat transport in 3-dimensional model simulations of the early Archean climate

    H. Kienert

    2013-01-01

    Full Text Available At the beginning of the Archean eon (ca. 3.8 billion yr ago, the Earth's climate state was significantly different from today due to the lower solar luminosity, smaller continental fraction, higher rotation rate and, presumably, significantly larger greenhouse gas concentrations. All these aspects play a role in solutions to the "faint young Sun problem" which must explain why the ocean surface was not fully frozen at that time. Here, we present 3-dimensional model simulations of climate states that are consistent with early Archean boundary conditions and have different CO2 concentrations, aiming at an understanding of the fundamental characteristics of the early Archean climate system. We focus on three states: one of them is ice-free, one has the same mean surface air temperature of 288 K as today's Earth and the third one is the coldest stable state in which there is still an area with liquid surface water (i.e. the critical state at the transition to a "snowball Earth". We find a reduction in meridional heat transport compared to today which leads to a steeper latitudinal temperature profile and has atmospheric as well as oceanic contributions. Ocean surface velocities are largely zonal, and the strength of the atmospheric meridional circulation is significantly reduced in all three states. These aspects contribute to the observed relation between global mean temperature and albedo, which we suggest as a parameterisation of the ice-albedo feedback for 1-dimensional model simulations of the early Archean and thus the faint young Sun problem.

  11. Development of a 3-dimensional dosimetry system for Leksell Gamma Knife Perfexion

    Yoon, KyoungJun; Kwak, JungWon; Lee, DoHeui; Cho, ByungChul; Lee, SangWook; Ahn, SeungDo

    2015-07-01

    The purpose of our study is to develop a new, 3-dimensional dosimetry system to verify the accuracy of dose deliveries in Leksell Gamma Knife Perfexion (LGKP) (Elekta, Norcross, GA, USA). The instrument consists of a moving head phantom, an embedded thin active layer and a CCD camera system and was designed to be mounted to LGKP. As an active material concentrically located in the hemispheric head phantom, we choose Gafchromic EBT3 films and Gd2O2S:Tb phosphor sheets for dosimetric measurements. Also, to compensate for the lack of backscatter, we located a 1-cm-thick poly methyl methacrylate (PMMA) plate downstream of the active layer. The PMMA plate was transparent to scintillation light to reach the CCD with 1200 × 1200 pixels and a 5.2 µm pitch. With this system, 300 images with a 0.2-mm slice gap were acquired under each of three collimator setups, i.e. 4-mm, 8-mm, and 16-mm, respectively. The 2D projected images taken by the CCD camera were compared with the dose distributions measured by the EBT3 films under the same conditions. All 2D distributions were normalized to the maximum values derived by fitting peaks for each collimator setup. The differences in the full widths at half maximum (FWHM) of 2D profiles between CCD images and film doses were measured to be less than 0.3-mm. The scanning task for all peak regions took less than three minutes with the new instrument. So it can be utilized as a QA tool for the Gamma knife radiosurgery system instead of film dosimetry, the use of which requires much more time and many more resources.

  12. SU-E-T-104: Development of 3 Dimensional Dosimetry System for Gamma Knife

    Yoon, K; Kwak, J; Cho, B; Lee, D; Ahn, S [Asan Medical Center, Seoul (Korea, Republic of)

    2014-06-01

    Purpose: The aim of this study was to develop a new 3 dimensional dosimetry system to verify the dosimetric accuracy of Leksell Gamma Knife-Perfexion™ (LGK) (Elekta, Norcross, GA). Methods: We designed and manufactured a lightweight dosimetry instrument to be equipped with the head frame to LGK. It consists of a head phantom, a scintillator, a CCD camera and a step motor. The 10×10 cm2 sheet of Gd2O3;Tb phosphor or Gafchromic EBT3 film was located at the center of the 16 cm diameter hemispherical PMMA, the head phantom. The additional backscatter compensating material of 1 cm thick PMMA plate was placed downstream of the phosphor sheet. The backscatter plate was transparent for scintillation lights to reach the CCD camera with 1200×1200 pixels by 5.2 um pitch. With This equipment, 300 images with 0.2 mm of slice gap were acquired under three collimator setups (4mm, 8mm and 16mm), respectively. The 2D projected doses from 3D distributions were compared with the exposured film dose. Results: As all doses normalized by the maximum dose value in 16 mm setup, the relative differences between the equipment dose and film dose were 0.2% for 4mm collimator and 0.5% for 8mm. The acquisition of 300 images by the equipment took less than 3 minutes. Conclusion: The new equipment was verified to be a good substitute to radiochromic film, with which required more time and resources. Especially, the new methods was considered to provide much convenient and faster solution in the 3D dose acquisition for LGK.

  13. The accuracy of reformatted images using a new virtual 3-dimensional dental implant system

    To compare the measurements of the mandible and the detectability of the mandibular canal on reformatted images using a newly developed 3-dimensional implant simulation program with traditionally used CT multiplanar reconstruction program and true measurements. Ten dry dog mandibles were used in this study. Occlusal templates for CT examination were fabricated and marked with gutta percha at ten sites. Axial CT scans were taken and reconstructed using DentaScan (D group) and Vimplant program (V group), and each mandible was sectioned at the previously marked sites (R group). Maximum vertical height (H) and maximum width (W) of the mandible, the distances from buccal border of the mandibular canal to the most buccal aspect of the mandible (X), and the distance from the superior border of the mandibular canal to the alveolar crest (Y) were measured, and the mandibular measurements in each group were compared. Detectability of mandibular canal was evaluated using a 3-point scale in both V and D groups by three oral radiologists and compared. H in the V group was slightly greater than that in the D group, and W and X in the V group was slightly less than those in the D group. H in the V group was less than that in the R group, and W and X in the V group was larger than those in the R group. The detectability of the mandibular canal did not show statistically significant differences between V and D groups. The results of the experiment show that the newly developed, inexpensive Vimplant simulation program can be used as an alternative to the traditionally used, and more expensive CT multiplanar reconstruction program.

  14. Oxidation behavior of ammonium in a 3-dimensional biofilm-electrode reactor.

    Tang, Jinjing; Guo, Jinsong; Fang, Fang; Chen, Youpeng; Lei, Lijing; Yang, Lin

    2013-12-01

    Excess nitrogenous compounds are detrimental to natural water systems and to human health. To completely realize autohydrogenotrophic nitrogen removal, a novel 3-dimensional biofilm-electrode reactor was designed. Titanium was electroplated with ruthenium and used as the anode. Activated carbon fiber felt was used as the cathode. The reactor was separated into two chambers by a permeable membrane. The cathode chamber was filled with granular graphite and glass beads. The cathode and cathode chamber were inhabited with domesticated biofilm. In the absence of organic substances, a nitrogen removal efficiency of up to 91% was achieved at DO levels of 3.42 +/- 0.37 mg/L when the applied current density was only 0.02 mA/cm2. The oxidation of ammonium in biofilm-electrode reactors was also investigated. It was found that ammonium could be oxidized not only on the anode but also on particle electrodes in the cathode chamber of the biofilm-electrode reactor. Oxidation rates of ammonium and nitrogen removal efficiency were found to be affected by the electric current loading on the biofilm-electrode reactor. The kinetic model of ammonium at different electric currents was analyzed by a first-order reaction kinetics equation. The regression analysis implied that when the current density was less than 0.02 mA/cm2, ammonium removal was positively correlated to the current density. However, when the current density was more than 0.02 mA/cm2, the electric current became a limiting factor for the oxidation rate of ammonium and nitrogen removal efficiency. PMID:24649670

  15. Interphase Chromosome Conformation and Chromatin-Chromatin Interactions in Human Epithelial Cells Cultured Under Different Gravity Conditions

    Zhang, Ye; Wong, Michael; Hada, Megumi; Wu, Honglu

    2015-01-01

    Microgravity has been shown to alter global gene expression patterns and protein levels both in cultured cells and animal models. It has been suggested that the packaging of chromatin fibers in the interphase nucleus is closely related to genome function, and the changes in transcriptional activity are tightly correlated with changes in chromatin folding. This study explores the changes of chromatin conformation and chromatin-chromatin interactions in the simulated microgravity environment, and investigates their correlation to the expression of genes located at different regions of the chromosome. To investigate the folding of chromatin in interphase under various culture conditions, human epithelial cells, fibroblasts, and lymphocytes were fixed in the G1 phase. Interphase chromosomes were hybridized with a multicolor banding in situ hybridization (mBAND) probe for chromosome 3 which distinguishes six regions of the chromosome as separate colors. After images were captured with a laser scanning confocal microscope, the 3-dimensional structure of interphase chromosome 3 was reconstructed at multi-mega base pair scale. In order to determine the effects of microgravity on chromosome conformation and orientation, measures such as distance between homologous pairs, relative orientation of chromosome arms about a shared midpoint, and orientation of arms within individual chromosomes were all considered as potentially impacted by simulated microgravity conditions. The studies revealed non-random folding of chromatin in interphase, and suggested an association of interphase chromatin folding with radiation-induced chromosome aberration hotspots. Interestingly, the distributions of genes with expression changes over chromosome 3 in cells cultured under microgravity environment are apparently clustered on specific loci and chromosomes. This data provides important insights into how mammalian cells respond to microgravity at molecular level.

  16. Dosimetric comparison of 3D conformal, IMRT, and V-MAT techniques for accelerated partial-breast irradiation (APBI)

    Qiu, Jian-Jian [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai (China); Chang, Zheng; Horton, Janet K.; Wu, Qing-Rong Jackie; Yoo, Sua [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States); Yin, Fang-Fang, E-mail: fangfang.yin@duke.edu [Department of Radiation Oncology, Duke University Medical Center, Durham, NC (United States)

    2014-07-01

    The purpose is to dosimetrically compare the following 3 delivery techniques: 3-dimensional conformal radiation therapy (3D-CRT), intensity-modulated arc therapy (IMRT), and volumetric-modulated arc therapy (V-MAT) in the treatment of accelerated partial-breast irradiation (APBI). Overall, 16 patients with T1/2N0 breast cancer were treated with 3D-CRT (multiple, noncoplanar photon fields) on the RTOG 0413 partial-breast trial. These cases were subsequently replanned using static gantry IMRT and V-MAT technology to understand dosimetric differences among these 3 techniques. Several dosimetric parameters were used in plan quality evaluation, including dose conformity index (CI) and dose-volume histogram analysis of normal tissue coverage. Quality assurance studies including gamma analysis were performed to compare the measured and calculated dose distributions. The IMRT and V-MAT plans gave more conformal target dose distributions than the 3D-CRT plans (p < 0.05 in CI). The volume of ipsilateral breast receiving 5 and 10 Gy was significantly less using the V-MAT technique than with either 3D-CRT or IMRT (p < 0.05). The maximum lung dose and the ipsilateral lung volume receiving 10 (V{sub 10}) or 20 Gy (V{sub 20}) were significantly less with both V-MAT and IMRT (p < 0.05). The IMRT technique was superior to 3D-CRT and V-MAT of low dose distributions in ipsilateral lung (p < 0.05 in V{sub 5} and D{sub 5}). The total mean monitor units (MUs) for V-MAT (621.0 ± 111.9) were 12.2% less than those for 3D-CRT (707.3 ± 130.9) and 46.5% less than those for IMRT (1161.4 ± 315.6) (p < 0.05). The average machine delivery time was 1.5 ± 0.2 minutes for the V-MAT plans, 7.0 ± 1.6 minutes for the 3D-CRT plans, and 11.5 ± 1.9 minutes for the IMRT plans, demonstrating much less delivery time for V-MAT. Based on this preliminary study, V-MAT and IMRT techniques offer improved dose conformity as compared with 3D-CRT techniques without increasing dose to the ipsilateral lung. In

  17. Dose comparisons for conformal, IMRT and VMAT prostate plans

    Volumetric-modulated arc therapy (VMAT) is a relatively new treatment technique in radiation therapy. A comparison study of conformal, intensity-modulated radiation therapy (IMRT) and single- and double-arc VMAT plans was undertaken to evaluate the dosimetric impact of this new technology in prostate cases. The research questions were as follows: how does VMAT dosimetry compare with IMRT and conformal plans?; does VMAT increase the volume of bowel receiving lower doses?; are one or two VMAT arcs required for standard prostate cases? Eight prostate cancer and post-prostatectomy patients were randomly selected for this study. Conformal, IMRT and single and double Arc VMAT plans were generated and dosimetric evaluations were performed. Each plan was prescribed a total of 75.6 Gy over a course of 42 fractions to the planning target volume (PTV). The Healthy Tissue Conformity Index and the conformation number results revealed the IMRT and two VMAT techniques to have superior dosimetry to the PTV compared with the conformal plans. The maximum dose delivered to the PTV was significantly higher with the single-arc VMAT technique compared with the conformal or double-arc VMAT plans. There were no significant differences between the planning techniques for the bladder and small bowel dosimetry. However, IMRT and VMAT plans delivered less radiation to the rectum and femoral heads, and a single-arc VMAT plan was optimal for the right femoral head and the two VMAT techniques were optimal to the IMRT plans for the left femoral head. Single- and double-arc VMAT consistently resulted in favourable or slightly superior dosimetry when compared with static gantry IMRT for prostate cases. Both the VMAT techniques and static gantry IMRT resulted in superior critical tissue sparing when compared with conformal plans.

  18. Conformally symmetric traversable wormholes

    Exact solutions of traversable wormholes are found under the assumption of spherical symmetry and the existence of a nonstatic conformal symmetry, which presents a more systematic approach in searching for exact wormhole solutions. In this work, a wide variety of solutions are deduced by considering choices for the form function, a specific linear equation of state relating the energy density and the pressure anisotropy, and various phantom wormhole geometries are explored. A large class of solutions impose that the spatial distribution of the exotic matter is restricted to the throat neighborhood, with a cutoff of the stress-energy tensor at a finite junction interface, although asymptotically flat exact solutions are also found. Using the 'volume integral quantifier', it is found that the conformally symmetric phantom wormhole geometries may, in principle, be constructed by infinitesimally small amounts of averaged null energy condition violating matter. Considering the tidal acceleration traversability conditions for the phantom wormhole geometry, specific wormhole dimensions and the traversal velocity are also deduced

  19. Titan global climate model: A new 3-dimensional version of the IPSL Titan GCM

    Lebonnois, Sébastien; Burgalat, Jérémie; Rannou, Pascal; Charnay, Benjamin

    2012-03-01

    We have developed a new 3-dimensional climate model for Titan’s atmosphere, using the physics of the IPSL Titan 2-dimensional climate model with the current version of the LMDZ General Circulation Model dynamical core. Microphysics and photochemistry are still computed as zonal averages. This GCM covers altitudes from surface to 500 km altitude, with barotropic waves now being resolved and the diurnal cycle included. The boundary layer scheme has been changed, yielding a strong improvement in the tropospheric zonal wind profile modeled at Huygens descent position and season. The potential temperature profile is fairly consistent with Huygens observations in the lowest 10 km. The latitudinal profile of the near-surface temperature is close to observed values. The minimum of zonal wind observed by the Huygens probe just above the tropopause is also present in these simulations, and its origin is discussed by comparing solar heating and dynamical transport of energy. The stratospheric temperature and wind fields are consistent with our previous works. Compared to observations, the zonal wind peak is too weak (around 120 m/s) and too low (around 200 km). The temperature structures appear to be compressed in altitude, and depart strongly from observations in the upper stratosphere. These discrepancies are correlated, and most probably related to the altitude of the haze production. The model produces a detached haze layer located more than 150 km lower than observed by the Cassini instruments. This low production altitude is due to the current position of the GCM upper boundary. However, the temporal behaviour of the detached haze layer in the model may explain the seasonal differences observed between Cassini and Voyager 1. The waves present in the GCM are analyzed, together with their respective roles in the angular momentum budget. Though the role of the mean meridional circulation in momentum transport is similar to previous work, and the transport by barotropic

  20. 3-Dimensional modelling of chick embryo eye development and growth using high resolution magnetic resonance imaging.

    Goodall, Nicola; Kisiswa, Lilian; Prashar, Ankush; Faulkner, Stuart; Tokarczuk, Paweł; Singh, Krish; Erichsen, Jonathan T; Guggenheim, Jez; Halfter, Willi; Wride, Michael A

    2009-10-01

    Magnetic resonance imaging (MRI) is a powerful tool for generating 3-dimensional structural and functional image data. MRI has already proven valuable in creating atlases of mouse and quail development. Here, we have exploited high resolution MRI to determine the parameters necessary to acquire images of the chick embryo eye. Using a 9.4 Tesla (400 MHz) high field ultra-shielded and refrigerated magnet (Bruker), MRI was carried out on paraformaldehyde-fixed chick embryos or heads at E4, E6, E8, and E10. Image data were processed using established and custom packages (MRICro, ImageJ, ParaVision, Bruker and mri3dX). Voxel dimensions ranged from 62.5 microm to 117.2 microm. We subsequently used the images obtained from the MRI data in order to make precise measurements of chick embryo eye surface area, volume and axial length from E4 to E10. MRI was validated for accurate sizing of ocular tissue features by direct comparison with previously published literature. Furthermore, we demonstrate the utility of high resolution MRI for making accurate measurements of morphological changes due to experimental manipulation of chick eye development, thereby facilitating a better understanding of the effects on chick embryo eye development and growth of such manipulations. Chondroitin sulphate or heparin were microinjected into the vitreous cavity of the right eyes of each of 3 embryos at E5. At E10, embryos were fixed and various eye parameters (volume, surface area, axial length and equatorial diameter) were determined using MRI and normalised with respect to the un-injected left eyes. Statistically significant alterations in eye volume (p < 0.05; increases with chondroitin sulphate and decreases with heparin) and changes in vitreous homogeneity were observed in embryos following microinjection of glycosaminoglycans. Furthermore, in the heparin-injected eyes, significant disturbances at the vitreo-retinal boundary were observed as well as retinal folding and detachment

  1. New Technique for Developing a Proton Range Compensator With Use of a 3-Dimensional Printer

    Ju, Sang Gyu, E-mail: sg.ju@samsung.com [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Min Kyu; Hong, Chae-Seon; Kim, Jin Sung; Han, Youngyih; Choi, Doo Ho [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Shin, Dongho; Lee, Se Byeong [Proton Therapy Center, National Cancer Center, Gyeonggi-do (Korea, Republic of)

    2014-02-01

    Purpose: A new system for manufacturing a proton range compensator (RC) was developed by using a 3-dimensional printer (3DP). The physical accuracy and dosimetric characteristics of the new RC manufactured by 3DP (RC{sub 3}DP) were compared with those of a conventional RC (RC{sub C}MM) manufactured by a computerized milling machine (CMM). Methods and Materials: An RC for brain tumor treatment with a scattered proton beam was calculated with a treatment planning system, and the resulting data were converted into a new format for 3DP using in-house software. The RC{sub 3}DP was printed with ultraviolet curable acrylic plastic, and an RC{sub C}MM was milled into polymethylmethacrylate using a CMM. The inner shape of both RCs was scanned by using a 3D scanner and compared with TPS data by applying composite analysis (CA; with 1-mm depth difference and 1 mm distance-to-agreement criteria) to verify their geometric accuracy. The position and distal penumbra of distal dose falloff at the central axis and field width of the dose profile at the midline depth of spread-out Bragg peak were measured for the 2 RCs to evaluate their dosimetric characteristics. Both RCs were imaged on a computed tomography scanner to evaluate uniformity of internal density. The manufacturing times for both RCs were compared to evaluate the production efficiency. Results: The pass rates for the CA test were 99.5% and 92.5% for RC{sub 3}DP and RC{sub C}MM, respectively. There was no significant difference in dosimetric characteristics and uniformity of internal density between the 2 RCs. The net fabrication times of RC{sub 3}DP and RC{sub C}MM were about 18 and 3 hours, respectively. Conclusions: The physical accuracy and dosimetric characteristics of RC{sub 3}DP were comparable with those of the conventional RC{sub C}MM, and significant system minimization was provided.

  2. Dimensional Reduction for Conformal Blocks

    Hogervorst, Matthijs

    2016-01-01

    We consider the dimensional reduction of a CFT, breaking multiplets of the d-dimensional conformal group SO(d+1,1) up into multiplets of SO(d,1). This leads to an expansion of d-dimensional conformal blocks in terms of blocks in d-1 dimensions. In particular, we obtain a formula for 3d conformal blocks as an infinite sum over 2F1 hypergeometric functions with closed-form coefficients.

  3. Fermion-Scalar Conformal Blocks

    Iliesiu, Luca; Poland, David; Pufu, Silviu S; Simmons-Duffin, David; Yacoby, Ran

    2015-01-01

    We compute the conformal blocks associated with scalar-scalar-fermion-fermion 4-point functions in 3D CFTs. Together with the known scalar conformal blocks, our result completes the task of determining the so-called `seed blocks' in three dimensions. Conformal blocks associated with 4-point functions of operators with arbitrary spins can now be determined from these seed blocks by using known differential operators.

  4. Einstein Gravity from Conformal Gravity

    Maldacena, Juan

    2011-01-01

    We show that that four dimensional conformal gravity plus a simple Neumann boundary condition can be used to get the semiclassical (or tree level) wavefunction of the universe of four dimensional asymptotically de-Sitter or Euclidean anti-de Sitter spacetimes. This simple Neumann boundary condition selects the Einstein solution out of the more numerous solutions of conformal gravity. It thus removes the ghosts of conformal gravity from this computation. In the case of a five dimensional pure ...

  5. Subtleties Concerning Conformal Tractor Bundles

    Graham, C Robin

    2012-01-01

    The realization of tractor bundles as associated bundles in conformal geometry is studied. It is shown that different natural choices of principal bundle with normal Cartan connection corresponding to a given conformal manifold can give rise to topologically distinct associated tractor bundles for the same inducing representation. Consequences for homogeneous models and conformal holonomy are described. A careful presentation is made of background material concerning standard tractor bundles and equivalence between parabolic geometries and underlying structures.

  6. Coends in conformal field theory

    Fuchs, Jürgen

    2016-01-01

    The idea of "summing over all intermediate states" that is central for implementing locality in quantum systems can be realized by coend constructions. In the concrete case of systems of conformal blocks for a certain class of conformal vertex algebras, one deals with coends in functor categories. Working with these coends involves quite a few subtleties which, even though they have in principle already been understood twenty years ago, have not been sufficiently appreciated by the conformal field theory community.

  7. Conformal Spectrum and Harmonic maps

    Nadirashvili, Nikolai

    2010-01-01

    This paper is devoted to the study of the conformal spectrum (and more precisely the first eigenvalue) of the Laplace-Beltrami operator on a smooth connected compact Riemannian surface without boundary, endowed with a conformal class. We give a constructive proof of a critical metric which is smooth except at some conical singularities and maximizes the first eigenvalue in the conformal class of the background metric. We also prove that the map associating a finite number of eigenvectors of the maximizing $\\lambda_1$ into the sphere is harmonic, establishing a link between conformal spectrum and harmonic maps.

  8. Reflections on Conformal Spectra

    CERN. Geneva

    2015-01-01

    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ0 of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ0 as well as for large Δ0. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function. (based on 1510.08772 with Kim & Ooguri). This seminar will be given via videolink

  9. Reflections on Conformal Spectra

    Kim, Hyungrok; Ooguri, Hirosi

    2015-01-01

    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions $\\Delta_0$ of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite $\\Delta_0$ as well as for large $\\Delta_0$. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function.

  10. Conformal Fermi Coordinates

    Dai, Liang; Schmidt, Fabian

    2015-01-01

    Fermi Normal Coordinates (FNC) are a useful frame for isolating the locally observable, physical effects of a long-wavelength spacetime perturbation. Their cosmological application, however, is hampered by the fact that they are only valid on scales much smaller than the horizon. We introduce a generalization that we call Conformal Fermi Coordinates (CFC). CFC preserve all the advantages of FNC, but in addition are valid outside the horizon. They allow us to calculate the coupling of long- and short-wavelength modes on all scales larger than the sound horizon of the cosmological fluid, starting from the epoch of inflation until today, by removing the complications of the second order Einstein equations to a large extent, and eliminating all gauge ambiguities. As an application, we present a calculation of the effect of long-wavelength tensor modes on small scale density fluctuations. We recover previous results, but clarify the physical content of the individual contributions in terms of locally measurable ef...

  11. Quality of coverage: conformity measures for stereotactic radiosurgery.

    Wu, Q-R Jackie; Wessels, B W; Einstein, D B; Maciunas, R J; Kim, E Y; Kinsella, T J

    2003-01-01

    In radiosurgery, conformity indices are often used to compare competing plans, evaluate treatment techniques, and assess clinical complications. Several different indices have been reported to measure the conformity of the prescription isodose to the target volume. The PITV recommended in the Radiation Therapy Oncology Group (RTOG) radiosurgery guidelines, defined as the ratio of the prescription isodose volume (PI) over the target volume (TV), is probably the most frequently quoted. However, these currently used conformity indices depend on target size and shape complexity. The objectives of this study are to systematically investigate the influence of target size and shape complexity on existing conformity indices, and to propose a different conformity index-the conformity distance index (CDI). The CDI is defined as the average distance between the target and the prescription isodose line. This study examines five case groups with volumes of 0.3, 1.0, 3.0, 10.0, and 30.0 cm(3). Each case group includes four simulated shapes: a sphere, a moderate ellipsoid, an extreme ellipsoid, and a concave "C" shape. Prescription dose coverages are generated for three simplified clinical scenarios, i.e., the PI completely covers the TV with 1 and 2 mm margins, and the PI over-covers one half of the TV with a 1 mm margin and under-covers the other half with a 1 mm margin. Existing conformity indices and the CDI are calculated for these five case groups as well as seven clinical cases. When these values are compared, the RTOG PITV conformity index and other similar conformity measures have much higher values than the CDI for smaller and more complex shapes. With the same quality of prescription dose coverage, the CDI yields a consistent conformity measure. For the seven clinical cases, we also find that the same PITV values can be associated with very different conformity qualities while the CDI predicts the conformity quality accurately. In summary, the proposed CDI provides

  12. Replacement between conformity and counter-conformity in consumption decisions.

    Chou, Ting-Jui; Chang, En-Chung; Dai, Qi; Wong, Veronica

    2013-02-01

    This study assessed, in a Chinese context, how self-esteem interacts with perceived similarity and uniqueness to yield cognitive dissonance, and whether the dissonance leads to self-reported conformity or counter-conformity behavior. Participants were 408 respondents from 4 major Chinese cities (M age = 33.0 yr., SD = 4.3; 48% men). Self-perceptions of uniqueness, similarity, cognitive dissonance, self-esteem and need to behave in conformity or counter-conformity were measured. A theoretical model was assessed in four situations, relating the ratings of self-esteem and perceived similarity/uniqueness to the way other people at a wedding were dressed, and the resultant cognitive dissonance and conformity/ counter-conformity behavior. Regardless of high or low self-esteem, all participants reported cognitive dissonance when they were told that they were dressed extremely similarly to or extremely differently from the other people attending the wedding. However, the conforming/counter-conforming strategies used by participants to resolve the cognitive dissonance differed. When encountering dissonance induced by the perceived extreme uniqueness of dress, participants with low self-esteem tended to say they would dress next time so as to conform with the way others were dressed, while those with high self-esteem indicated they would continue their counter-conformity in attire. When encountering dissonance induced by the perceived extreme similarity to others, both those with high and low self-esteem tended to say they would dress in an unorthodox manner to surprise other people in the future. PMID:23654033

  13. Editorial Commentary: Single-Image Slice Magnetic Resonance Imaging Assessments Do Not Predict 3-Dimensional Muscle Volume.

    Brand, Jefferson C

    2016-01-01

    No single-image magnetic resonance imaging (MRI) assessment-Goutallier classification, Fuchs classification, or cross-sectional area-is predictive of whole-muscle volume or fatty atrophy of the supraspinatus or infraspinatus. Rather, 3-dimensional MRI measurement of whole-muscle volume and fat-free muscle volume is required and is associated with shoulder strength, which is clinically relevant. Three-dimensional MRI may represent a new gold standard for assessment of the rotator cuff musculature using imaging and may help to predict the feasibility of repair of a rotator cuff tear as well as the postoperative outcome. Unfortunately, 3-dimensional MRI assessment of muscle volume is labor intensive and is not widely available for clinical use. PMID:26743416

  14. Modern Radiation Therapy for Hodgkin Lymphoma: Field and Dose Guidelines From the International Lymphoma Radiation Oncology Group (ILROG)

    Radiation therapy (RT) is the most effective single modality for local control of Hodgkin lymphoma (HL) and an important component of therapy for many patients. These guidelines have been developed to address the use of RT in HL in the modern era of combined modality treatment. The role of reduced volumes and doses is addressed, integrating modern imaging with 3-dimensional (3D) planning and advanced techniques of treatment delivery. The previously applied extended field (EF) and original involved field (IF) techniques, which treated larger volumes based on nodal stations, have now been replaced by the use of limited volumes, based solely on detectable nodal (and extranodal extension) involvement at presentation, using contrast-enhanced computed tomography, positron emission tomography/computed tomography, magnetic resonance imaging, or a combination of these techniques. The International Commission on Radiation Units and Measurements concepts of gross tumor volume, clinical target volume, internal target volume, and planning target volume are used for defining the targeted volumes. Newer treatment techniques, including intensity modulated radiation therapy, breath-hold, image guided radiation therapy, and 4-dimensional imaging, should be implemented when their use is expected to decrease significantly the risk for normal tissue damage while still achieving the primary goal of local tumor control. The highly conformal involved node radiation therapy (INRT), recently introduced for patients for whom optimal imaging is available, is explained. A new concept, involved site radiation therapy (ISRT), is introduced as the standard conformal therapy for the scenario, commonly encountered, wherein optimal imaging is not available. There is increasing evidence that RT doses used in the past are higher than necessary for disease control in this era of combined modality therapy. The use of INRT and of lower doses in early-stage HL is supported by available data. Although the

  15. Modern Radiation Therapy for Hodgkin Lymphoma: Field and Dose Guidelines From the International Lymphoma Radiation Oncology Group (ILROG)

    Specht, Lena, E-mail: lena.specht@regionh.dk [Department of Oncology and Hematology, Rigshospitalet, University of Copenhagen (Denmark); Yahalom, Joachim [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Illidge, Tim [Institute of Cancer Sciences, University of Manchester, Manchester Academic Health Sciences Centre, Christie Hospital NHS Trust, Manchester (United Kingdom); Berthelsen, Anne Kiil [Department of Radiation Oncology and PET Centre, Rigshospitalet, University of Copenhagen (Denmark); Constine, Louis S. [Department of Radiation Oncology and Pediatrics, James P. Wilmot Cancer Center, University of Rochester Medical Center, Rochester, New York (United States); Eich, Hans Theodor [Department of Radiation Oncology, University of Münster (Germany); Girinsky, Theodore [Department of Radiation Oncology, Institut Gustave-Roussy, Villejuif (France); Hoppe, Richard T. [Department of Radiation Oncology, Stanford University, Stanford, California (United States); Mauch, Peter [Department of Radiation Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Harvard University, Boston, Massachusetts (United States); Mikhaeel, N. George [Department of Clinical Oncology and Radiotherapy, Guy' s and St Thomas' NHS Foundation Trust, London (United Kingdom); Ng, Andrea [Department of Radiation Oncology, Brigham and Women' s Hospital and Dana-Farber Cancer Institute, Harvard University, Boston, Massachusetts (United States)

    2014-07-15

    Radiation therapy (RT) is the most effective single modality for local control of Hodgkin lymphoma (HL) and an important component of therapy for many patients. These guidelines have been developed to address the use of RT in HL in the modern era of combined modality treatment. The role of reduced volumes and doses is addressed, integrating modern imaging with 3-dimensional (3D) planning and advanced techniques of treatment delivery. The previously applied extended field (EF) and original involved field (IF) techniques, which treated larger volumes based on nodal stations, have now been replaced by the use of limited volumes, based solely on detectable nodal (and extranodal extension) involvement at presentation, using contrast-enhanced computed tomography, positron emission tomography/computed tomography, magnetic resonance imaging, or a combination of these techniques. The International Commission on Radiation Units and Measurements concepts of gross tumor volume, clinical target volume, internal target volume, and planning target volume are used for defining the targeted volumes. Newer treatment techniques, including intensity modulated radiation therapy, breath-hold, image guided radiation therapy, and 4-dimensional imaging, should be implemented when their use is expected to decrease significantly the risk for normal tissue damage while still achieving the primary goal of local tumor control. The highly conformal involved node radiation therapy (INRT), recently introduced for patients for whom optimal imaging is available, is explained. A new concept, involved site radiation therapy (ISRT), is introduced as the standard conformal therapy for the scenario, commonly encountered, wherein optimal imaging is not available. There is increasing evidence that RT doses used in the past are higher than necessary for disease control in this era of combined modality therapy. The use of INRT and of lower doses in early-stage HL is supported by available data. Although the

  16. Intelligent Layout Method of the Powerhouse for Tank & Armored Vehicles Based on 3-Dimensional Rectangular Packing Theory

    WANG Yan-long; MAO Ming; LU Yi-ping; BIE Jie-min

    2005-01-01

    Probes into a new and effective method in arranging the powerhouses of tank & armored vehicles. Theory and method of 3-dimensional rectangular packing are adapted to arrange effectively almost all the systems and components in the powerhouse of the vehicle, thus the study can be regarded as an attempt for the theory's engineering applications in the field of tank & armored vehicle design. It is proved that most parts of the solutions attained are reasonable, and some of the solutions are innovative.

  17. Accuracy of 3-Dimensional Transoesophageal Echocardiography in Assessment of Prosthetic Mitral Valve Dehiscence with Comparison to Anatomical Specimens

    Martin R. Brown

    2010-01-01

    Full Text Available The evolution of echocardiography from 2-Dimensional Transthoracic Echo through to real time 3-Dimensional Transoesophageal Echo has enabled more accurate visualisation and quantification of valvular disorders especially prosthetic mitral valve paravalvular regurgitation. However, validation of accuracy is rarely confirmed by surgical or post-mortem specimens. We present a case directly comparing different echocardiographic modality images to post mortem specimens in a patient with prosthetic mitral valve paravalvular regurgitation.

  18. Heating-Rate-Triggered Carbon-Nanotube-based 3-Dimensional Conducting Networks for a Highly Sensitive Noncontact Sensing Device

    Yanlong Tai; Gilles Lubineau

    2016-01-01

    Recently, flexible and transparent conductive films (TCFs) are drawing more attention for their central role in future applications of flexible electronics. Here, we report the controllable fabrication of TCFs for moisture-sensing applications based on heating-rate-triggered, 3-dimensional porous conducting networks through drop casting lithography of single-walled carbon nanotube (SWCNT)/poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) ink. How ink formula and baking condit...

  19. Classical Virasoro irregular conformal block

    Rim, Chaiho

    2015-01-01

    Virasoro irregular conformal block with arbitrary rank is obtained for the classical limit or equivalently Nekrasov-Shatashvili limit using the beta-deformed irregular matrix model (Penner-type matrix model for the irregular conformal block). The same result is derived using the generalized Mathieu equation which is equivalent to the loop equation of the irregular matrix model.

  20. Conformal invariance in harmonic superspace

    N=2 conformal supersymmetry is realized in harmonic superspace, its peculiarities are analyzed. The coordinate group and analytical prepotentials for N=2 conformal supergravity are found. A new version of the N=2 Einstein supergravity with infinite number of auxiliary fields is suggested. A hypermultiplet without central charges and constraints is used as a compensator

  1. Conformal gravity and time

    Hazboun, Jeffrey Shafiq

    2014-10-01

    Cartan geometry provides a rich formalism from which to look at various geometrically motivated extensions to general relativity. In this manuscript, we start by motivating reasons to extend the theory of general relativity. We then introduce the reader to our technique, called the quotient manifold method, for extending the geometry of spacetime. We will specifically look at the class of theories formed from the various quotients of the conformal group. Starting with the conformal symmetries of Euclidean space, we construct a manifold where time manifests as a part of the geometry. Though there is no matter present in the geome- try studied here, geometric terms analogous to dark energy and dark matter appear when we write down the Einstein tensor. Specifically, the quotient of the conformal group of Euclidean four-space by its Weyl subgroup results in a geometry possessing many of the properties of relativistic phase space, including both a natural symplectic form and nondegenerate Killing metric. We show the general solution possesses orthogonal Lagrangian submanifolds, with the induced metric and the spin connection on the submanifolds necessarily Lorentzian, despite the Euclidean starting point. By examining the structure equations of the biconformal space in an orthonormal frame adapted to its phase space properties, we also find two new tensor fields exist in this geometry, not present in Riemannian geometry. The first is a combination of the Weyl vector with the scale factor on the metric, and determines the time-like directions on the submanifolds. The second comes from the components of the spin connection, symmetric with respect to the new metric. Though this field comes from the spin connection, it transforms ho- mogeneously. Finally, we show in the absence of Cartan curvature or sources, the configuration space has geometric terms equivalent to a perfect fluid and a cosmological constant. We complete the analysis of this homogeneous space by

  2. Preparation of 1-3 Dimensional PZT-NFO Nanocomposite Films by Off-axis Magnetron Sputtering

    ZHANG Hui, MA Yong-Jun, WANG Yi-Cheng, WEN Dan-Dan, YE Fei, BAI Fei-Ming

    2014-04-01

    Full Text Available Self-assembled nanocomposite Pb(Zr0.52Ti0.48O3-NiFe2O4 films were prepared on the (001-oriented MgAl2O4 substrates by a 90° off-axis magnetron sputtering method. The influences of substrate temperature, argon over oxygen ratio and sputtering power on the structure and properties of PZT-NFO nanocomposite films were studied. The optimal growth conditions are substrate temperature of 800 °C, argon over oxygen ratio of 1:1 and sputtering power of 160 W. XRD studies reveal that the PZT-NFO film is epitaxial along both the in-plane and out-of-plane directions, and the vertical lattice mismatch between the PZT phase and the NFO phase is very small. AFM and SEM analysis show that the PZT-NFO films have clear 1-3 dimensional nanocomposite structure, and the diameter of NFO nanorods is 80-150 nm. Further decreasing argon over oxygen ratio is beneficial for the formation of NFO. However, increasing RF power causes a transition from an 1-3 dimensional nanocomposite to a 0-3 dimensional chaotic structure. Magnetic measurement shows that the saturation magnetization of NFO phase is 120-160 kA/m, lower than that of bulk NFO phase, possibly due to the interfacial diffusion between the NFO and the PZT phases.

  3. Unified description of magic numbers of metal clusters in terms of the 3-dimensional q-deformed harmonic oscillator

    Bonatsos, Dennis; Lenis, D; Raychev, P P; Roussev, R P; Terziev, P A

    2000-01-01

    Magic numbers predicted by a 3-dimensional q-deformed harmonic oscillator with Uq(3)>SOq(3) symmetry are compared to experimental data for atomic clusters of alkali metals (Li, Na, K, Rb, Cs), noble metals (Cu, Ag, Au), divalent metals (Zn, Cd), and trivalent metals (Al, In), as well as to theoretical predictions of jellium models, Woods-Saxon and wine bottle potentials, and to the classification scheme using the 3n+l pseudo quantum number. In alkali metal clusters and noble metal clusters the 3-dimensional q-deformed harmonic oscillator correctly predicts all experimentally observed magic numbers up to 1500 (which is the expected limit of validity for theories based on the filling of electronic shells), while in addition it gives satisfactory results for the magic numbers of clusters of divalent metals and trivalent metals, thus indicating that Uq(3), which is a nonlinear extension of the U(3) symmetry of the spherical (3-dimensional isotropic) harmonic oscillator, is a good candidate for being the symmetry ...

  4. Projectors, Shadows, and Conformal Blocks

    Simmons-Duffin, David

    2012-01-01

    We introduce a method for computing conformal blocks of operators in arbitrary Lorentz representations in any spacetime dimension, making it possible to apply bootstrap techniques to operators with spin. The key idea is to implement the "shadow formalism" of Ferrara, Gatto, Grillo, and Parisi in a setting where conformal invariance is manifest. Conformal blocks in d-dimensions can be expressed as integrals over the projective null-cone in the "embedding space" R^{d+1,1}. Taking care with their analytic structure, these integrals can be evaluated in great generality, reducing the computation of conformal blocks to a bookkeeping exercise. To facilitate calculations in four-dimensional CFTs, we introduce techniques for writing down conformally-invariant correlators using auxiliary twistor variables, and demonstrate their use in some simple examples.

  5. Recursion Relations for Conformal Blocks

    Penedones, João; Yamazaki, Masahito

    2015-01-01

    In the context of conformal field theories in general space-time dimension, we find all the possible singularities of the conformal blocks as functions of the scaling dimension $\\Delta$ of the exchanged operator. In particular, we argue, using representation theory of parabolic Verma modules, that in odd spacetime dimension the singularities are only simple poles. We discuss how to use this information to write recursion relations that determine the conformal blocks. We first recover the recursion relation introduced in 1307.6856 for conformal blocks of external scalar operators. We then generalize this recursion relation for the conformal blocks associated to the four point function of three scalar and one vector operator. Finally we specialize to the case in which the vector operator is a conserved current.

  6. Towards conformal loop quantum gravity

    Wang, C H T

    2006-01-01

    A discussion is given of recent developments in canonical gravity that assimilates the conformal analysis of gravitational degrees of freedom. The work is motivated by the problem of time in quantum gravity and is carried out at the metric and the triad levels. At the metric level, it is shown that by extending the Arnowitt-Deser-Misner (ADM) phase space of general relativity (GR), a conformal form of geometrodynamics can be constructed. In addition to the Hamiltonian and diffeomorphism constraints, an extra first class constraint is introduced to generate conformal transformations. This phase space consists of York's mean extrinsic curvature time, conformal three-metric and their momenta. At the triad level, the phase space of GR is further enlarged by incorporating spin-gauge as well as conformal symmetries. This leads to a canonical formulation of GR using a new set of real spin connection variables. The resulting gravitational constraints are first class, consisting of the Hamiltonian constraint and the c...

  7. Standard fractionation intensity modulated radiation therapy (IMRT of primary and recurrent glioblastoma multiforme

    Fuller Clifton D

    2007-07-01

    Full Text Available Abstract Background Intensity-modulated radiation therapy (IMRT affords unparalleled capacity to deliver conformal radiation doses to tumors in the central nervous system. However, to date, there are few reported outcomes from using IMRT, either alone or as a boost technique, for standard fractionation radiotherapy for glioblastoma multiforme (GBM. Methods Forty-two patients were treated with IMRT alone (72% or as a boost (28% after 3-dimensional conformal radiation therapy (3D-CRT. Thirty-three patients with primary disease and 9 patients with recurrent tumors were included. Thirty-four patients (81% had surgery, with gross tumor resection in 13 patients (36%; 22 patients (53% received chemo-radiotherapy. The median total radiation dose for all patients was 60 Gy with a range from 30.6 to 74 Gy. Standard fractions of 1.8 Gy/day to 2.0 Gy/day were utilized. Results Median survival was 8.7 months, with 37 patients (88% deceased at last contact. Nonparametric analysis showed no survival difference in IMRT-boost vs. IMRT-only groups. Conclusion While technically feasible, preliminary results suggest delivering standard radiation doses by IMRT did not improve survival outcomes in this series compared to historical controls. In light of this lack of a survival benefit and the costs associated with use of IMRT, future prospective trials are needed to evaluate non-survival endpoints such as quality of life and functional preservation. Short of such evidence, the use of IMRT for treatment of GBM needs to be carefully rationalized.

  8. The Conformal Standard Model

    Latosinski, Adam; Meissner, Krzysztof A; Nicolai, Hermann

    2015-01-01

    We present an extended version of the Conformal Standard Model (characterized by the absence of any new intermediate scales between the electroweak scale and the Planck scale) with an enlarged scalar sector coupling to right-chiral neutrinos in such a way that the scalar potential and the Yukawa couplings involving only right-chiral neutrinos are invariant under a new global symmetry SU(3)$_N$ which is broken explicitly only by the Yukawa interaction coupling right-chiral neutrinos and the electroweak lepton doublets. We point out four main advantages of such an enlargement, namely: (1) the economy of the (non-supersymmetric) Standard Model, and thus its observational success, is preserved; (2) thanks to the enlarged scalar sector the RG improved one-loop effective potential is everywhere positive with a stable global minimum, thereby avoiding the notorious instability of the Standard Model vacuum; (3) the pseudo-Goldstone bosons resulting from spontaneous breaking of the SU(3)$_N$ symmetry are natural Dark M...

  9. Conformational Dynamics of Insulin

    Qing-xin eHua

    2011-10-01

    Full Text Available We have exploited a prandial insulin analogue (insulin lispro, the active component of Humalog®; Eli Lilly and Co. to elucidate the underlying structure and dynamics of insulin as a monomer in solution. Whereas NMR-based modeling recapitulates structural relationships of insulin crystals (T-state protomers, dynamic anomalies are revealed by amide-proton exchange kinetics in D2O. Surprisingly, the majority of hydrogen bonds observed in crystal structures are only transiently maintained in solution, including key T-state-specific inter-chain contacts. Long-lived hydrogen bonds (as defined by global exchange kinetics exist only at a subset of four -helical sites (two per chain flanking an internal disulfide bridge (cystine A20-B19; these sites map within the proposed folding nucleus of proinsulin. The anomalous flexibility of insulin otherwise spans its active surface and may facilitate receptor binding. Because conformational fluctuations promote the degradation of pharmaceutical formulations, we envisage that dynamic re-engineering of insulin may enable design of ultra-stable formulations for humanitarian use in the developing world.

  10. Imaging of conformational changes

    Michl, Josef [Univ. of Colorado, Boulder, CO (United States)

    2016-03-13

    Control of intramolecular conformational change in a small number of molecules or even a single one by an application of an outside electric field defined by potentials on nearby metal or dielectric surfaces has potential applications in both 3-D and 2-D nanotechnology. Specifically, the synthesis, characterization, and understanding of designed solids with controlled built-in internal rotational motion of a dipole promises a new class of materials with intrinsic dielectric, ferroelectric, optical and optoelectronic properties not found in nature. Controlled rotational motion is of great interest due to its expected utility in phenomena as diverse as transport, current flow in molecular junctions, diffusion in microfluidic channels, and rotary motion in molecular machines. A direct time-resolved observation of the dynamics of motion on ps or ns time scale in a single molecule would be highly interesting but is also very difficult and has yet to be accomplished. Much can be learned from an easier but still challenging comparison of directly observed initial and final orientational states of a single molecule, which is the basis of this project. The project also impacts the understanding of surface-enhanced Raman spectroscopy (SERS) and single-molecule spectroscopic detection, as well as the synthesis of solid-state materials with tailored properties from designed precursors.

  11. Combined Treatment Effects of Radiation and Immunotherapy: Studies in an Autochthonous Prostate Cancer Model

    Wada, Satoshi [Department of Oncology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Harris, Timothy J.; Tryggestad, Erik [Department of Radiation Oncology and Molecular Radiation Sciences, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Yoshimura, Kiyoshi [Department of Oncology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Zeng, Jing [Department of Radiation Oncology and Molecular Radiation Sciences, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Yen, Hung-Rong; Getnet, Derese; Grosso, Joseph F.; Bruno, Tullia C. [Department of Oncology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); De Marzo, Angelo M. [Department of Pathology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); Department of Urology, James Buchanan Brady Urological Institute, Johns Hopkins Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland (United States); and others

    2013-11-15

    Purpose: To optimize the combination of ionizing radiation and cellular immunotherapy using a preclinical autochthonous model of prostate cancer. Methods and Materials: Transgenic mice expressing a model antigen under a prostate-specific promoter were treated using a platform that integrates cone-beam CT imaging with 3-dimensional conformal therapy. Using this technology we investigated the immunologic and therapeutic effects of combining ionizing radiation with granulocyte/macrophage colony-stimulating factor-secreting cellular immunotherapy for prostate cancer in mice bearing autochthonous prostate tumors. Results: The combination of ionizing radiation and immunotherapy resulted in a significant decrease in pathologic tumor grade and gross tumor bulk that was not evident with either single-modality therapy. Furthermore, combinatorial therapy resulted in improved overall survival in a preventive metastasis model and in the setting of established micrometastases. Mechanistically, combined therapy resulted in an increase of the ratio of effector-to-regulatory T cells for both CD4 and CD8 tumor-infiltrating lymphocytes. Conclusions: Our preclinical model establishes a potential role for the use of combined radiation-immunotherapy in locally advanced prostate cancer, which warrants further exploration in a clinical setting.

  12. First Order Electroweak Phase Transition from (Non)Conformal Extensions of the Standard Model

    Sannino, Francesco; Virkajärvi, Jussi

    2015-01-01

    We analyse and compare the finite-temperature electroweak phase transition properties of classically (non)conformal extensions of the Standard Model. In the classically conformal scenarios the breaking of the electroweak symmetry is generated radiatively. The models feature new scalars coupled...

  13. Towards conformal loop quantum gravity

    H-T Wang, Charles

    2006-03-01

    A discussion is given of recent developments in canonical gravity that assimilates the conformal analysis of gravitational degrees of freedom. The work is motivated by the problem of time in quantum gravity and is carried out at the metric and the triad levels. At the metric level, it is shown that by extending the Arnowitt-Deser-Misner (ADM) phase space of general relativity (GR), a conformal form of geometrodynamics can be constructed. In addition to the Hamiltonian and Diffeomorphism constraints, an extra first class constraint is introduced to generate conformal transformations. This phase space consists of York's mean extrinsic curvature time, conformal three-metric and their momenta. At the triad level, the phase space of GR is further enlarged by incorporating spin-gauge as well as conformal symmetries. This leads to a canonical formulation of GR using a new set of real spin connection variables. The resulting gravitational constraints are first class, consisting of the Hamiltonian constraint and the canonical generators for spin-gauge and conformorphism transformations. The formulation has a remarkable feature of being parameter-free. Indeed, it is shown that a conformal parameter of the Barbero-Immirzi type can be absorbed by the conformal symmetry of the extended phase space. This gives rise to an alternative approach to loop quantum gravity that addresses both the conceptual problem of time and the technical problem of functional calculus in quantum gravity.

  14. Late rectal toxicity after non conformational external radiotherapy for prostate cancer

    With a non conformational technique distributing a radiation dose of 68 Gy to the prostate, the rate of bad or medium anorectal function and the rectum hemorrhages rate needing a medical treatment does not exceed 4%. (N.C.)

  15. Simultaneous Bimaxillary Surgery and Mandibular Reconstruction With a 3-Dimensional Printed Titanium Implant Fabricated by Electron Beam Melting: A Preliminary Mechanical Testing of the Printed Mandible.

    Lee, Ui-Lyong; Kwon, Jae-Sung; Woo, Su-Heon; Choi, Young-Jun

    2016-07-01

    A woman presented with a long history of mandibular defects posterior to the left lower first premolar caused by inadequate reconstruction after removal of a tumor on the left side of the mandible. In the frontal view, extreme facial asymmetry was apparent. The dental midline of the mandible was deviated 10 mm to the left compared with the dental midline of the maxilla, and all maxillary teeth were inclined to the left owing to dental compensation. There was an 8-mm maxillary occlusal cant relative to the maxillary first molar. Bimaxillary surgery using computer-assisted designed and computer-assisted manufactured devices without an intermediate occlusal splint was performed to align the maxilla and mandible at the correct position, and reconstructive surgery for the mandible using a 3-dimensional printed titanium mandible was concurrently performed. In particular, during the virtual mandible design, 2 abutments that enabled the prosthetic restoration were included in the mandible using a computer-assisted design program. This report describes the successful functional and esthetic reconstruction of the mandible using electron beam melting technology, an alternative technique for reconstruction of mandibles that did not undergo radiation therapy. PMID:27060494

  16. Locally conformal symplectic manifolds

    Izu Vaisman

    1985-01-01

    Full Text Available A locally conformal symplectic (l. c. s. manifold is a pair (M2n,Ω where M2n(n>1 is a connected differentiable manifold, and Ω a nondegenerate 2-form on M such that M=⋃αUα (Uα- open subsets. Ω/Uα=eσαΩα, σα:Uα→ℝ, dΩα=0. Equivalently, dΩ=ω∧Ω for some closed 1-form ω. L. c. s. manifolds can be seen as generalized phase spaces of Hamiltonian dynamical systems since the form of the Hamilton equations is, in fact, preserved by homothetic canonical transformations. The paper discusses first Hamiltonian vector fields, and infinitesimal automorphisms (i. a. on l. c. s. manifolds. If (M,Ω has an i. a. X such that ω(X≠0, we say that M is of the first kind and Ω assumes the particular form Ω=dθ−ω∧θ. Such an M is a 2-contact manifold with the structure forms (ω,θ, and it has a vertical 2-dimensional foliation V. If V is regular, we can give a fibration theorem which shows that M is a T2-principal bundle over a symplectic manifold. Particularly, V is regular for some homogeneous l. c. s, manifolds, and this leads to a general construction of compact homogeneous l. c. s, manifolds. Various related geometric results, including reductivity theorems for Lie algebras of i. a. are also given. Most of the proofs are adaptations of corresponding proofs in symplectic and contact geometry. The paper ends with an Appendix which states an analogous fibration theorem in Riemannian geometry.

  17. Conformal Tensors via Lovelock Gravity

    Kastor, David

    2013-01-01

    Constructs from conformal geometry are important in low dimensional gravity models, while in higher dimensions the higher curvature interactions of Lovelock gravity are similarly prominent. Considering conformal invariance in the context of Lovelock gravity leads to natural, higher-curvature generalizations of the Weyl, Schouten, Cotton and Bach tensors, with properties that straightforwardly extend those of their familiar counterparts. As a first application, we introduce a new set of conformally invariant gravity theories in D=4k dimensions, based on the squares of the higher curvature Weyl tensors.

  18. Local conformity induced global oscillation

    Li, Dong; Li, Wei; Hu, Gang; Zheng, Zhigang

    2009-04-01

    The game ‘rock-paper-scissors’ model, with the consideration of the effect of the psychology of conformity, is investigated. The interaction between each two agents is global, but the strategy of the conformity is local for individuals. In the statistical opinion, the probability of the appearance of each strategy is uniform. The dynamical analysis of this model indicates that the equilibrium state may lose its stability at a threshold and is replaced by a globally oscillating state. The global oscillation is induced by the local conformity, which is originated from the synchronization of individual strategies.

  19. Conformal radiotherapy: revolution or evolution?

    The advantage the most clearly known of a conformal approach takes place in the protection of sane tissues. A randomized study comparing classical radiotherapy and conformal (defined with the use of masks) has noticed a significant reduction of the delayed rectal toxicity after conformal irradiation for patients suffering of prostate tumor. This benefit has been observed with a simple technique (three beams) and a dose not really high (66 Gy). It could bring a safety margin in the case of increasing of the tumor dose. (N.C.)

  20. Conformal extensions for stationary spacetimes

    Aceña, Andrés E

    2011-01-01

    The construction of the cylinder at spatial infinity for stationary spacetimes is considered. Using a specific conformal gauge and frame, it is shown that the tensorial fields associated to the conformal Einstein field equations admit expansions in a neighbourhood of the cylinder at spatial infinity which are analytic with respect to some suitable time, radial and angular coordinates. It is then shown that the essentials of the construction are independent of the choice of conformal gauge. As a consequence, one finds that the construction of the cylinder at spatial infinity and the regular finite initial value problem for stationary initial data sets are, in a precise sense, as regular as they could be.

  1. Antibody sensed protein surface conformation

    Scott R. Schricker

    2011-12-01

    Full Text Available An antibody-modified atomic force microscope (AFM tip was used to detect conformational changes of fibronectin deposited on a poly(methyl methacrylate/poly(acrylic acid block copolymer compared to PMMA and a random poly(methyl methacrylate/poly(acrylic acid copolymer with an identical chemical composition. Based on the antibody-protein adhesive force maps and phase imaging, it was found that the nanomorphology of the triblock copolymer induces the desired conformation of fibronectin. This finding demonstrates that block copolymer nanomorphology can be used to regulate protein conformation and potentially cellular response.

  2. Conformal Patterson-Walker metrics

    Hammerl, Matthias; Šilhan, Josef; Taghavi-Chabert, Arman; Žádník, Vojtěch

    2016-01-01

    The classical Patterson-Walker construction of a split-signature (pseudo-)Riemannian structure from a given torsion-free affine connection is generalized to a construction of a split-signature conformal structure from a given projective class of connections. A characterization of the induced structures is obtained. We achieve a complete description of Einstein metrics in the conformal class formed by the Patterson-Walker metric. Finally, we describe all symmetries of the conformal Patterson-Walker metric. In both cases we obtain descriptions in terms of geometric data on the original structure.

  3. Advances in image-guided radiation therapy-the role of PET-CT

    In the era of image-guided radiation therapy (IGRT), the greatest challenge remains target delineation, as the opportunity to maximize cures while simultaneously decreasing radiation dose to the surrounding normal tissues is to be realized. Over the last 2 decades, technological advances in radiographic imaging, biochemistry, and molecular biology have played an increasing role in radiation treatment planning, delivery, and evaluation of response. Previously, fluoroscopy formed the basis of radiation treatment planning. Beginning in the late 1980s, computed tomography (CT) has become the basis for modern radiation treatment planning and delivery, coincident with the rise of 3-dimensional conformal radiation therapy (3DCRT). Additionally, multi-modality anatomic imaging registration was the solution pursued to augment delineation of tumors and surrounding structures on CT-based treatment planning. Although these imaging modalities provide the customary anatomic details necessary for radiation treatment planning, they have limitations, including difficulty with identification of small tumor deposits, tumor extension, and distinction from scar tissues. To overcome these limitations, PET and, more recently, PET-CT have been innovative regarding the extent of disease appraisal, target delineation in the treatment planning, and assessment of therapy response. We review the role of functional imaging in IGRT as it reassures transformations on the field of radiation oncology. As we move toward the era of IGRT, the use of multi-modality imaging fusion, and the introduction of more sensitive and specific PET-CT tracers may further assist target definition. Furthermore, the potential to predict early outcome or even detect early recurrence of tumor, may allow for the tailoring of intervention in cancer patients. The convergence of a biological target volume, and perhaps multi-tracer tumor, molecular, and genetic profile tumors will probably be vital in cancer treatment

  4. Logarithmic conformal field theory

    Gainutdinov, Azat; Ridout, David; Runkel, Ingo

    2013-12-01

    Conformal field theory (CFT) has proven to be one of the richest and deepest subjects of modern theoretical and mathematical physics research, especially as regards statistical mechanics and string theory. It has also stimulated an enormous amount of activity in mathematics, shaping and building bridges between seemingly disparate fields through the study of vertex operator algebras, a (partial) axiomatisation of a chiral CFT. One can add to this that the successes of CFT, particularly when applied to statistical lattice models, have also served as an inspiration for mathematicians to develop entirely new fields: the Schramm-Loewner evolution and Smirnov's discrete complex analysis being notable examples. When the energy operator fails to be diagonalisable on the quantum state space, the CFT is said to be logarithmic. Consequently, a logarithmic CFT is one whose quantum space of states is constructed from a collection of representations which includes reducible but indecomposable ones. This qualifier arises because of the consequence that certain correlation functions will possess logarithmic singularities, something that contrasts with the familiar case of power law singularities. While such logarithmic singularities and reducible representations were noted by Rozansky and Saleur in their study of the U (1|1) Wess-Zumino-Witten model in 1992, the link between the non-diagonalisability of the energy operator and logarithmic singularities in correlators is usually ascribed to Gurarie's 1993 article (his paper also contains the first usage of the term 'logarithmic conformal field theory'). The class of CFTs that were under control at this time was quite small. In particular, an enormous amount of work from the statistical mechanics and string theory communities had produced a fairly detailed understanding of the (so-called) rational CFTs. However, physicists from both camps were well aware that applications from many diverse fields required significantly more

  5. Adjuvant Chemoradiation for Gastric Cancer Using Epirubicin, Cisplatin, and 5-Fluorouracil Before and After Three-Dimensional Conformal Radiotherapy With Concurrent Infusional 5-Fluorouracil: A Multicenter Study of the Trans-Tasman Radiation Oncology Group

    Purpose: The INT0116 study has established postoperative chemoradiotherapy as the standard of care for completely resected gastric adenocarcinoma. However, the optimal chemoradiation regimen remains to be defined. We conducted a prospective, multicenter study to evaluate an alternative chemoradiation regimen that combines more current systemic treatment with modern techniques of radiotherapy delivery. Methods and Materials: Patients with adenocarcinoma of the stomach who had undergone an R0 resection were eligible. Adjuvant therapy consisted of one cycle of epirubicin, cisplatin, and 5-FU (ECF), followed by radiotherapy with concurrent infusional 5-FU, and then two additional cycles of ECF. Radiotherapy was delivered using precisely defined, multiple-field, three-dimensional conformal techniques. Results: A total of 54 assessable patients were enrolled from 19 institutions. The proportion of patients commencing Cycles 1, 2, and 3 of ECF chemotherapy were 100%, 81%, and 67% respectively. In all, 94% of patients who received radiotherapy completed treatment as planned. Grade 3/4 neutropenia occurred in 66% of patients with 7.4% developing febrile neutropenia. Most neutropenic episodes (83%) occurred in the post-radiotherapy period during cycles 2 and 3 of ECF. Grade 3/4 gastrointestinal toxicity occurred in 28% of patients. In all, 35% of radiotherapy treatment plans contained protocol deviations that were satisfactorily amended before commencement of treatment. At median follow-up of 36 months, the 3-year overall survival rate was estimated at 61.6%. Conclusions: This adjuvant regimen using ECF before and after three-dimensional conformal chemoradiation is feasible and can be safely delivered in a cooperative group setting. A regimen similar to this is currently being compared with the INT0116 regimen in a National Cancer Institute-sponsored, randomized Phase III trial.

  6. Some Progress in Conformal Geometry

    Sun-Yung A. Chang

    2007-12-01

    Full Text Available This is a survey paper of our current research on the theory of partial differential equations in conformal geometry. Our intention is to describe some of our current works in a rather brief and expository fashion. We are not giving a comprehensive survey on the subject and references cited here are not intended to be complete. We introduce a bubble tree structure to study the degeneration of a class of Yamabe metrics on Bach flat manifolds satisfying some global conformal bounds on compact manifolds of dimension 4. As applications, we establish a gap theorem, a finiteness theorem for diffeomorphism type for this class, and diameter bound of the $sigma_2$-metrics in a class of conformal 4-manifolds. For conformally compact Einstein metrics we introduce an eigenfunction compactification. As a consequence we obtain some topological constraints in terms of renormalized volumes.

  7. "Induced" N=4 conformal supergravity

    Buchbinder, I L; Tseytlin, A A

    2012-01-01

    We consider an abelian N=4 super Yang-Mills theory coupled to background N=4 conformal supergravity fields. At the classical level, this coupling is invariant under global SU(1,1) transformation of the complex ("dilaton-axion") supergravity scalar combined with an on-shell vector-vector duality. We compute the divergent part of the corresponding quantum effective action found by integrating over the super Yang-Mills fields and demonstrate its SU(1,1) invariance. This divergent part related to the conformal anomaly is one-loop exact and should be given by the N=4 conformal supergravity action containing the Weyl tensor squared term. This allows us to determine the full non-linear form of the bosonic part of the N=4 conformal supergravity action which has manifest SU(1,1) invariance.

  8. National Automated Conformity Inspection Process

    Department of Transportation — The National Automated Conformity Inspection Process (NACIP) Application is intended to expedite the workflow process as it pertains to the FAA Form 81 0-10 Request...

  9. Conformation Distributions in Adsorbed Proteins.

    Meuse, Curtis W.; Hubbard, Joseph B.; Vrettos, John S.; Smith, Jackson R.; Cicerone, Marcus T.

    2007-03-01

    While the structural basis of protein function is well understood in the biopharmaceutical and biotechnology industries, few methods for the characterization and comparison of protein conformation distributions are available. New methods capable of measuring the stability of protein conformations and the integrity of protein-protein, protein-ligand and protein-surface interactions both in solution and on surfaces are needed to help the development of protein-based products. We are developing infrared spectroscopy methods for the characterization and comparison of molecular conformation distributions in monolayers and in solutions. We have extracted an order parameter describing the orientational and conformational variations of protein functional groups around the average molecular values from a single polarized spectrum. We will discuss the development of these methods and compare them to amide hydrogen/deuterium exchange methods for albumin in solution and on different polymer surfaces to show that our order parameter is related to protein stability.

  10. Scalar perturbations and conformal transformation

    The non-minimal coupling of gravity to a scalar field can be transformed into a minimal coupling through a conformal transformation. We show how to connect the results of a perturbation calculation, performed around a Friedman-Robertson-Walker background solution, before and after the conformal transformation. We work in the synchronous gauge, but we discuss the implications of employing other frames. (author). 16 refs

  11. Conformal Gravity on Noncommutative Spacetime

    Kober, Martin

    2011-01-01

    Conformal gravity on noncommutative spacetime is considered in this paper. The presupposed gravity action consists of the Brans-Dicke gravity action with a special prefactor of the term, where the Ricci scalar couples to the scalar field, to maintain local conformal invariance and the Weyl gravity action. The commutation relations between the coordinates defining the noncommutative geometry are assumed to be of canonical shape. Based on the moyal star product, products of fields depending on ...

  12. Factors influencing conformity index in radiotherapy for non-small cell lung cancer.

    Brennan, Sinead M; Thirion, Pierre; Buckney, Steve; Shea, Carmel O; Armstrong, John

    2010-01-01

    The radiotherapy conformity index (CI) is a useful tool to quantitatively assess the quality of radiotherapy treatment plans, and represents the relationship between isodose distributions and target volume. A conformity index of unity implies high planning target volume (PTV) coverage and minimal unnecessary irradiation of surrounding tissues. We performed this analysis to describe the CI for lung cancer 3-dimensional conformal radiotherapy (3DCRT) and to identify clinical and technical determinants of CI, as it is not known which factors are associated with good quality 3D conformal radiotherapy treatment planning. Radiotherapy treatment plans from a database of 52 patients with inoperable Stage 1 to 3b lung cancer, on a hypofractionated 3DCRT trial were evaluated. A CI was calculated for all plans using the definition of the ICRU 62:CI = (TV/PTV), which is the quotient of the treated volume (TV) and the PTV. Data on patient, tumor, and planning variables, which could influence CI, were recorded and analyzed. Mean CI was 2.01 (range = 1.06-3.8). On univariate analysis, PTV (p = 0.023), number of beams (p = 0.036), medial vs. lateral tumor location (p = 0.016), and increasing tumor stage (p = 0.041) were associated with improved conformity. On multiple regression analysis, factors found to be associated with CI included central vs. peripheral tumor location (p = 0.041) and PTV size (p = 0.058). The term 3DCRT is used routinely in the literature, without any indication of the degree of conformality. We recommend routine reporting of conformity indices. Conformity indices may be affected by both planning variables and tumor factors. PMID:19931013

  13. Factors Influencing Conformity Index in Radiotherapy for Non-Small Cell Lung Cancer

    The radiotherapy conformity index (CI) is a useful tool to quantitatively assess the quality of radiotherapy treatment plans, and represents the relationship between isodose distributions and target volume. A conformity index of unity implies high planning target volume (PTV) coverage and minimal unnecessary irradiation of surrounding tissues. We performed this analysis to describe the CI for lung cancer 3-dimensional conformal radiotherapy (3DCRT) and to identify clinical and technical determinants of CI, as it is not known which factors are associated with good quality 3D conformal radiotherapy treatment planning. Radiotherapy treatment plans from a database of 52 patients with inoperable Stage 1 to 3b lung cancer, on a hypofractionated 3DCRT trial were evaluated. A CI was calculated for all plans using the definition of the ICRU 62:CI = (TV/PTV), which is the quotient of the treated volume (TV) and the PTV. Data on patient, tumor, and planning variables, which could influence CI, were recorded and analyzed. Mean CI was 2.01 (range = 1.06-3.8). On univariate analysis, PTV (p = 0.023), number of beams (p = 0.036), medial vs. lateral tumor location (p = 0.016), and increasing tumor stage (p = 0.041) were associated with improved conformity. On multiple regression analysis, factors found to be associated with CI included central vs. peripheral tumor location (p = 0.041) and PTV size (p = 0.058). The term 3DCRT is used routinely in the literature, without any indication of the degree of conformality. We recommend routine reporting of conformity indices. Conformity indices may be affected by both planning variables and tumor factors.

  14. Factors influencing conformity index in radiotherapy for non-small cell lung cancer.

    Brennan, Sinead M

    2010-01-01

    The radiotherapy conformity index (CI) is a useful tool to quantitatively assess the quality of radiotherapy treatment plans, and represents the relationship between isodose distributions and target volume. A conformity index of unity implies high planning target volume (PTV) coverage and minimal unnecessary irradiation of surrounding tissues. We performed this analysis to describe the CI for lung cancer 3-dimensional conformal radiotherapy (3DCRT) and to identify clinical and technical determinants of CI, as it is not known which factors are associated with good quality 3D conformal radiotherapy treatment planning. Radiotherapy treatment plans from a database of 52 patients with inoperable Stage 1 to 3b lung cancer, on a hypofractionated 3DCRT trial were evaluated. A CI was calculated for all plans using the definition of the ICRU 62:CI = (TV\\/PTV), which is the quotient of the treated volume (TV) and the PTV. Data on patient, tumor, and planning variables, which could influence CI, were recorded and analyzed. Mean CI was 2.01 (range = 1.06-3.8). On univariate analysis, PTV (p = 0.023), number of beams (p = 0.036), medial vs. lateral tumor location (p = 0.016), and increasing tumor stage (p = 0.041) were associated with improved conformity. On multiple regression analysis, factors found to be associated with CI included central vs. peripheral tumor location (p = 0.041) and PTV size (p = 0.058). The term 3DCRT is used routinely in the literature, without any indication of the degree of conformality. We recommend routine reporting of conformity indices. Conformity indices may be affected by both planning variables and tumor factors.

  15. Development of 3-dimensional time-dependent density functional theory and its application to gas diffusion in nanoporous materials.

    Liu, Yu

    2016-05-11

    I developed a novel time-dependent density functional theory (TDDFT) and applied it to complicated 3-dimensional systems for the first time. Superior to conventional TDDFT, the diffusion coefficient is modeled as a function of density profile, which is self-determined by the entropy scaling rule instead using an input parameter. The theory was employed to mimic gas diffusion in a nanoporous material. The TDDFT prediction on the transport diffusivity was reasonable compared to simulations. Moreover, the time-dependent density profiles gave an insight into the microscopic mechanism of the diffusion process. PMID:27121986

  16. 3-dimensional local field polarization vector mapping of a focused radially polarized beam using gold nanoparticle functionalized tips.

    Ahn, J S; Kihm, H W; Kihm, J E; Kim, D S; Lee, K G

    2009-02-16

    We have measured local electric field polarization vectors in 3-dimensional space on the nanoscale. A radial polarized light is generated by using a radial polarization converter and focused by an objective lens. Gold nanoparticle functionalized tips are used to scatter the focused field into the far-field region. Two different methods, rotational analyzer ellipsometry and Stokes parameters, are used in determining the polarization state of the scattered light. Two methods give consistent results with each other. Three dimensional local polarization vectors could be reconstructed by applying back transformation of the fully characterized polarizability tensor of the tip. PMID:19219131

  17. Experimental Validation of Plastic Mandible Models Produced by a “Low-Cost” 3-Dimensional Fused Deposition Modeling Printer

    Maschio, Federico; Pandya, Mirali; Olszewski, Raphael

    2016-01-01

    Background The objective of this study was to investigate the accuracy of 3-dimensional (3D) plastic (ABS) models generated using a low-cost 3D fused deposition modelling printer. Material/Methods Two human dry mandibles were scanned with a cone beam computed tomography (CBCT) Accuitomo device. Preprocessing consisted of 3D reconstruction with Maxilim software and STL file repair with Netfabb software. Then, the data were used to print 2 plastic replicas with a low-cost 3D fused deposition mo...

  18. Falsification of Mannheim's conformal gravity

    Yoon, Youngsub

    2013-01-01

    We show that Mannheim's conformal gravity, whose potential has a term proportional to $1/r$ and another term proportional to $r$, doesn't reduce to Newtonian gravity at short distances. Therefore, despite the claim that it successfully explains galaxy rotation curves, it seems falsified by numerous Cavendish-type experiments performed at laboratories on Earth whose work haven't found any deviations from Newton's theory. Moreover, when Mannheim used his potential to fit the galaxy rotation curve, he used the Newtonian formula to calculate the effects of the term proportional to $1/r$, not the conformal gravity one. So, he lacked consistency. After all, he would not have been able to use the conformal gravity one either since it deviates so much from the Newtonian one, which the conformal gravity one should reduce to. We also give a couple of other similar reasons why Mannheim's conformal gravity is wrong. For example, the gravitational potential of conformal gravity doesn't reduce to the Newtonian one even in ...

  19. 18F-fluorodeoxyglucose Positron Emisson Tomography/Computed Tomography Guided Conformal Brachytherapy for Cervical Cancer

    Purpose: To evaluate the feasibility of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT)-guided conformal brachytherapy treatment planning in patients with cervical cancer. Methods and Materials: Pretreatment FDG-PET/CT was performed for 12 patients with cervical cancer. Brachytherapy simulation was performed after an external-beam radiation therapy median dose of 4140 cGy. Patients underwent FDG-PET/CT scans with placement of tandem and ovoid applicators. The gross tumor volume (GTV) was determined by adjusting the window and level to a reasonable value and outlining the edge of the enhancing area, which was done in consultation with a nuclear medicine physician. A standardized uptake value profile of the tumor margin was taken for each patient relative to the maximum uptake value of each tumor and analyzed. The plan was designed to deliver 400 cGy to point A (point A plan) or to cover the clinical target volume (CTV) (PET/CT plan). Results: The median dose that encompassed 95% of the target volume (D95) of the CTV was 323.0 cGy for the point A plan vs 399.0 cGy for the PET/CT plan (P=.001). The maximum standardized uptake values (SUVmax) of the tumors were reduced by a median of 57% (range, 13%-80%). All but 1 patient presented with discernable residual uptake within the tumors. The median value of the thresholds of the tumors contoured by simple visual analysis was 41% (range, 23%-71%). Conclusions: In this study, the PET/CT plan was better than the conventional point A plan in terms of target coverage without increasing the dose to the normal tissue, making optimized 3-dimensional brachytherapy treatment planning possible. In comparison with the previously reported study with PET or CT alone, we found that visual target localization was facilitated by PET fusion on indeterminate CT masses. Further studies are needed to characterize the metabolic activity detected during radiation therapy for more reliable targeting.

  20. 18F-fluorodeoxyglucose Positron Emisson Tomography/Computed Tomography Guided Conformal Brachytherapy for Cervical Cancer

    Nam, Heerim [Department of Radiation Oncology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Huh, Seung Jae, E-mail: sj5201.huh@samsung.com [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Ju, Sang Gyu; Park, Won; Lee, Jeong Eun [Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Choi, Joon Young; Kim, Byung-Tae [Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Chan Kyo; Park, Byung Kwan [Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2012-09-01

    Purpose: To evaluate the feasibility of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT)-guided conformal brachytherapy treatment planning in patients with cervical cancer. Methods and Materials: Pretreatment FDG-PET/CT was performed for 12 patients with cervical cancer. Brachytherapy simulation was performed after an external-beam radiation therapy median dose of 4140 cGy. Patients underwent FDG-PET/CT scans with placement of tandem and ovoid applicators. The gross tumor volume (GTV) was determined by adjusting the window and level to a reasonable value and outlining the edge of the enhancing area, which was done in consultation with a nuclear medicine physician. A standardized uptake value profile of the tumor margin was taken for each patient relative to the maximum uptake value of each tumor and analyzed. The plan was designed to deliver 400 cGy to point A (point A plan) or to cover the clinical target volume (CTV) (PET/CT plan). Results: The median dose that encompassed 95% of the target volume (D95) of the CTV was 323.0 cGy for the point A plan vs 399.0 cGy for the PET/CT plan (P=.001). The maximum standardized uptake values (SUV{sub max}) of the tumors were reduced by a median of 57% (range, 13%-80%). All but 1 patient presented with discernable residual uptake within the tumors. The median value of the thresholds of the tumors contoured by simple visual analysis was 41% (range, 23%-71%). Conclusions: In this study, the PET/CT plan was better than the conventional point A plan in terms of target coverage without increasing the dose to the normal tissue, making optimized 3-dimensional brachytherapy treatment planning possible. In comparison with the previously reported study with PET or CT alone, we found that visual target localization was facilitated by PET fusion on indeterminate CT masses. Further studies are needed to characterize the metabolic activity detected during radiation therapy for more reliable targeting.