Patient-specific quality assurance and plan dose errors on breast intensity-modulated proton therapy

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.

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First Clinical Experience of Quality Assurance CT Scan Adapted Intensity Modulated Proton Therapy for Utero-cervical Cancers

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2020.07.1537 ◽

2020 ◽

Vol 108 (3) ◽

pp. e483

Author(s):

P. Mohindra ◽

A.E. Pollock ◽

A.N. Patel ◽

D.M. Roque ◽

G. Rao ◽

...

Keyword(s):

Quality Assurance ◽

Ct Scan ◽

Clinical Experience ◽

Proton Therapy ◽

Cervical Cancers ◽

Intensity Modulated Proton Therapy ◽

Intensity Modulated

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Patient-specific bolus for range shifter air gap reduction in intensity-modulated proton therapy of head-and-neck cancer studied with Monte Carlo based plan optimization

Radiotherapy and Oncology ◽

10.1016/j.radonc.2017.09.006 ◽

2018 ◽

Vol 128 (1) ◽

pp. 161-166 ◽

Cited By ~ 9

Author(s):

Steven Michiels ◽

Ana Maria Barragán ◽

Kevin Souris ◽

Kenneth Poels ◽

Wouter Crijns ◽

...

Keyword(s):

Monte Carlo ◽

Head And Neck Cancer ◽

Head And Neck ◽

Neck Cancer ◽

Proton Therapy ◽

Air Gap ◽

Patient Specific ◽

Intensity Modulated Proton Therapy ◽

Intensity Modulated ◽

Plan Optimization

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Hounsfield Unit Correction for Dental Implant Materials in Intensity Modulated Proton Therapy of Head and Neck Cancer: A Quality Assurance Benchmark Study

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2014.05.2620 ◽

2014 ◽

Vol 90 (1) ◽

pp. S925-S926

Author(s):

B. Ager ◽

A. Mohamed ◽

M.B. Palmer ◽

C.A. Wages ◽

X. Zhu ◽

...

Keyword(s):

Quality Assurance ◽

Head And Neck Cancer ◽

Head And Neck ◽

Dental Implant ◽

Neck Cancer ◽

Proton Therapy ◽

Hounsfield Unit ◽

Intensity Modulated Proton Therapy ◽

Benchmark Study ◽

Intensity Modulated

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An Anthropomorphic Head and Neck Quality Assurance Phantom for Credentialing of Intensity-Modulated Proton Therapy

International Journal of Particle Therapy ◽

10.14338/ijpt-17-00005.1 ◽

2017 ◽

Vol 4 (3) ◽

pp. 40-47 ◽

Cited By ~ 2

Author(s):

Daniela Branco ◽

Paige Taylor ◽

Xiaodong Zhang ◽

Heng Li ◽

Michele Guindani ◽

...

Keyword(s):

Quality Assurance ◽

Head And Neck ◽

Proton Therapy ◽

Intensity Modulated Proton Therapy ◽

Intensity Modulated

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Evaluation of dosimetric advantages of using patient‐specific aperture system with intensity‐modulated proton therapy for the shallow depth tumor

Journal of Applied Clinical Medical Physics ◽

10.1002/acm2.12231 ◽

2017 ◽

Vol 19 (1) ◽

pp. 132-137 ◽

Cited By ~ 9

Author(s):

Keisuke Yasui ◽

Toshiyuki Toshito ◽

Chihiro Omachi ◽

Kensuke Hayashi ◽

Kenichiro Tanaka ◽

...

Keyword(s):

Proton Therapy ◽

Shallow Depth ◽

Patient Specific ◽

Intensity Modulated Proton Therapy ◽

Intensity Modulated

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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 ◽

10.3390/cancers13071549 ◽

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.

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