SU-F-BRD-06: Robust Dose Calculation in Intensity Modulated Proton Therapy

2015 ◽  
Vol 42 (6Part25) ◽  
pp. 3526-3527
Author(s):  
R Brosch ◽  
W Liu
Keyword(s):  
Proton Therapy ◽  
Dose Calculation ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated

scholarly journals Is an analytical dose engine sufficient for intensity modulated proton therapy in lung cancer?

2020 ◽  
Vol 93 (1107) ◽  
pp. 20190583 ◽  
Author(s):  
Suliana Teoh ◽  
Francesca Fiorini ◽  
Ben George ◽  
Katherine A Vallis ◽  
Frank Van den Heuvel
Keyword(s):  
Lung Cancer ◽  
Proton Therapy ◽  
Dose Calculation ◽  
Target Volume ◽  
Pass Rates ◽  
Final Dose ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Mediastinal Disease ◽  
Mediastinal Involvement

Objective: To identify a subgroup of lung cancer plans where the analytical dose calculation (ADC) algorithm may be clinically acceptable compared to Monte Carlo (MC) dose calculation in intensity modulated proton therapy (IMPT). Methods: Robust-optimised IMPT plans were generated for 20 patients to a dose of 70 Gy (relative biological effectiveness) in 35 fractions in Raystation. For each case, four plans were generated: three with ADC optimisation using the pencil beam (PB) algorithm followed by a final dose calculation with the following algorithms: PB (PB-PB), MC (PB-MC) and MC normalised to prescription dose (PB-MC scaled). A fourth plan was generated where MC optimisation and final dose calculation was performed (MC-MC). Dose comparison and γ analysis (PB-PB vs PB-MC) at two dose thresholds were performed: 20% (D20) and 99% (D99) with PB-PB plans as reference. Results: Overestimation of the dose to 99% and mean dose of the clinical target volume was observed in all PB-MC compared to PB-PB plans (median: 3.7 Gy(RBE) (5%) (range: 2.3 to 6.9 Gy(RBE)) and 1.8 Gy(RBE) (3%) (0.5 to 4.6 Gy(RBE))). PB-MC scaled plans resulted in significantly higher CTVD2 compared to PB-PB (median difference: −4 Gy(RBE) (−6%) (-5.3 to −2.4 Gy(RBE)), p ≤ .001). The overall median γ pass rates (3%–3 mm) at D20 and D99 were 93.2% (range:62.2–97.5%) and 71.3 (15.4–92.0%). On multivariate analysis, presence of mediastinal disease and absence of range shifters were significantly associated with high γ pass rates. Median D20 and D99 pass rates with these predictors were 96.0% (95.3–97.5%) and 85.4% (75.1–92.0%). MC-MC achieved similar target coverage and doses to OAR compared to PB-PB plans. Conclusion: In the presence of mediastinal involvement and absence of range shifters Raystation ADC may be clinically acceptable in lung IMPT. Otherwise, MC algorithm would be recommended to ensure accuracy of treatment plans. Advances in knowledge: Although MC algorithm is more accurate compared to ADC in lung IMPT, ADC may be clinically acceptable where there is mediastinal involvement and absence of range shifters.

scholarly journals Transitioning from measurement-based to combined patient-specific quality assurance for intensity-modulated proton therapy

2020 ◽  
Vol 93 (1107) ◽  
pp. 20190669 ◽  
Author(s):  
Mei Chen ◽  
Pablo Yepes ◽  
Yoshifumi Hojo ◽  
Falk Poenisch ◽  
Yupeng Li ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Proton Therapy ◽  
Dose Calculation ◽  
Patient Specific ◽  
Calculation Algorithm ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Passing Rate ◽  
Clinical Scenarios ◽  
Beam Modeling

Objective: This study is part of ongoing efforts aiming to transit from measurement-based to combined patient-specific quality assurance (PSQA) in intensity-modulated proton therapy (IMPT). A Monte Carlo (MC) dose-calculation algorithm is used to improve the independent dose calculation and to reveal the beam modeling deficiency of the analytical pencil beam (PB) algorithm. Methods: A set of representative clinical IMPT plans with suboptimal PSQA results were reviewed. Verification plans were recalculated using an MC algorithm developed in-house. Agreements of PB and MC calculations with measurements that quantified by the γ passing rate were compared. Results: The percentage of dose planes that met the clinical criteria for PSQA (>90% γ passing rate using 3%/3 mm criteria) increased from 71.40% in the original PB calculation to 95.14% in the MC recalculation. For fields without beam modifiers, nearly 100% of the dose planes exceeded the 95% γ passing rate threshold using the MC algorithm. The model deficiencies of the PB algorithm were found in the proximal and distal regions of the SOBP, where MC recalculation improved the γ passing rate by 11.27% (p < 0.001) and 16.80% (p < 0.001), respectively. Conclusions: The MC algorithm substantially improved the γ passing rate for IMPT PSQA. Improved modeling of beam modifiers would enable the use of the MC algorithm for independent dose calculation, completely replacing additional depth measurements in IMPT PSQA program. For current users of the PB algorithm, further improving the long-tail modeling or using MC simulation to generate the dose correction factor is necessary. Advances in knowledge: We justified a change in clinical practice to achieve efficient combined PSQA in IMPT by using the MC algorithm that was experimentally validated in almost all the clinical scenarios in our center. Deficiencies in beam modeling of the current PB algorithm were identified and solutions to improve its dose-calculation accuracy were provided.

A robust intensity modulated proton therapy optimizer based on Monte Carlo dose calculation

2018 ◽  
Vol 45 (9) ◽  
pp. 4045-4054 ◽  
Author(s):  
Jiasen Ma ◽  
Hok Seum Wan Chan Tseung ◽  
Michael G. Herman ◽  
Chris Beltran
Keyword(s):  
Monte Carlo ◽  
Proton Therapy ◽  
Dose Calculation ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Monte Carlo Dose Calculation

scholarly journals Early Clinical Outcomes of Intensity Modulated Radiation Therapy/Intensity Modulated Proton Therapy Combination in Comparison with Intensity Modulated Radiation Therapy Alone in Oropharynx Cancer Patients

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1549
Author(s):  
Han Gyul Yoon ◽  
Yong Chan Ahn ◽  
Dongryul Oh ◽  
Jae Myoung Noh ◽  
Seung Gyu Park ◽  
...  
Keyword(s):  
Radiation Therapy ◽  
Proton Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Combination Group ◽  
Intensity Modulated Proton Therapy ◽  
Oropharynx Cancer ◽  
Intensity Modulated ◽  
Before And After ◽  
Grade 3 ◽  
Early Clinical Outcomes

Purpose: To report the early clinical outcomes of combining intensity-modulated radiation therapy (IMRT) and intensity-modulated proton therapy (IMPT) in comparison with IMRT alone in treating oropharynx cancer (OPC) patients. Materials and Methods: The medical records of 148 OPC patients who underwent definitive radiotherapy (RT) with concurrent systemic therapy, from January 2016 till December 2019 at Samsung Medical Center, were retrospectively reviewed. During the 5.5 weeks’ RT course, the initial 16 (or 18) fractions were delivered by IMRT in all patients, and the subsequent 12 (or 10) fractions were either by IMRT in 81 patients (IMRT only) or by IMPT in 67 (IMRT/IMPT combination), respectively, based on comparison of adaptive re-plan profiles and availability of equipment. Propensity-score matching (PSM) was done on 76 patients (38 from each group) for comparative analyses. Results: With the median follow-up of 24.7 months, there was no significant difference in overall survival and progression free survival between groups, both before and after PSM. Before PSM, the IMRT/IMPT combination group experienced grade ≥ 3 acute toxicities less frequently: mucositis in 37.0% and 13.4% (p < 0.001); and analgesic quantification algorithm (AQA) in 37.0% and 19.4% (p = 0.019), respectively. The same trends were observed after PSM: mucositis in 39.5% and 15.8% (p = 0.021); and AQA in 47.4% and 21.1% (p = 0.016), respectively. In multivariate logistic regression, grade ≥ 3 mucositis was significantly less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.027 and 0.024, respectively). AQA score ≥ 3 was also less frequent in the IMRT/IMPT combination group, both before and after PSM (p = 0.085 and 0.018, respectively). Conclusions: In treating the OPC patients, with comparable early oncologic outcomes, more favorable acute toxicity profiles were achieved following IMRT/IMPT combination than IMRT alone.

scholarly journals Multiple Computed Tomography Robust Optimization to Account for Random Anatomic Density Variations During Intensity Modulated Proton Therapy

2020 ◽  
Vol 5 (5) ◽  
pp. 1022-1031 ◽  
Author(s):  
Mingyao Zhu ◽  
Adeel Kaiser ◽  
Mark V. Mishra ◽  
Young Kwok ◽  
Jill Remick ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Robust Optimization ◽  
Proton Therapy ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated

PO-0930 ROBUSTNESS OF IMPT (INTENSITY MODULATED PROTON THERAPY) COMPARED WITH IMRT FOR HEAD AND NECK CANCERS

2012 ◽  
Vol 103 ◽  
pp. S366-S367
Author(s):  
R. Harding ◽  
J. Lilley ◽  
V.P. Cosgrove ◽  
S.J. Weston ◽  
C.M. Thompson ◽  
...  
Keyword(s):  
Head And Neck ◽  
Proton Therapy ◽  
Head And Neck Cancers ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated

scholarly journals Bone marrow sparing in intensity modulated proton therapy for cervical cancer: Efficacy and robustness under range and setup uncertainties

2015 ◽  
Vol 115 (3) ◽  
pp. 373-378 ◽  
Author(s):  
Eric Dinges ◽  
Nicole Felderman ◽  
Sarah McGuire ◽  
Brandie Gross ◽  
Sudershan Bhatia ◽  
...  
Keyword(s):  
Cervical Cancer ◽  
Bone Marrow ◽  
Proton Therapy ◽  
Intensity Modulated Proton Therapy ◽  
Intensity Modulated ◽  
Bone Marrow Sparing
Sign in / Sign up

Export Citation Format

Share Document