Clinical commissioning of Monte Carlo algorithm for synchrotron-based spot scanning proton therapy system
10.3760/cma.j.cn113030-20240407-00129
- VernacularTitle:同步加速器质子点扫描治疗系统的蒙特卡罗算法临床调试
- Author:
Mei CHEN
1
;
Yuanlin YAN
;
Hui ZHOU
;
Xuming JIANG
;
Yibin ZHANG
;
Xiaodong HE
;
Lu CAO
;
Zhiling CHEN
;
Manzhou ZHANG
;
Cheng XU
;
Jiayi CHEN
Author Information
1. 上海交通大学医学院附属瑞金医院放射治疗科，上海 200025
- Publication Type:Journal Article
- Keywords:
Synchrotron;
Spot scanning proton therapy;
Monte Carlo algorithm;
Clinical commissioning
- From:
Chinese Journal of Radiation Oncology
2025;34(3):275-281
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To illustrate the clinical modeling and commissioning results of Monte Carlo dose calculation algorithm in RayStation treatment planning system (TPS) for a domestically developed synchrotron-based spot scanning proton therapy system (SAPT-PS-01).Methods:The proton pencil beam model in RayStation required integral depth dose curves, spot profiles and absolute dose as the input beam data. It was not necessary to collect beam parameters with range shifter. The integral depth dose curves of a single spot were measured by an 8 cm parallel ion chamber. A 2-dimensional scintillation detector was used to measure the in-air spot profile at 5 different depths including the isocenter plane. The absolute dose was calibrated by a 0.25 cm parallel ion chamber under the single energy layer irradiation with a field size of 10 cm × 10 cm. After modeling, the results of the beam model and the Monte Carlo dose calculation algorithm were validated from the range, spot profile, point-dose in a spread-out Bragg peak, planar dose in a clinical plan, point dose in an end-to-end test.Results:For the 94 energy layers, the maximum deviation between the calculated and measured range was 0.03 cm. The maximum difference between the calculated and measured in-air spot sigma was 0.015 cm, and the deviation of in-water spot sigma was measured within ±15%. Compared with the measured values, the calculated dose deviation of 138 measured points in the spread-out Bragg peak was within 3%. For the planar dose verification of clinical plans, the TPS-calculated dose distribution of 285 planes agreed well with the measurement with a minimum gamma-passing rate of 90%, and the gamma passing rate of almost 95% of planes were greater than 95%. The point dose measurements for 8 beams in the end-to-end tests under 4 clinical scenarios were within 5%.Conclusions:The acceptable beam model validation results and successful end-to-end test confirm that the Monte Carlo dose calculation algorithm modeling for the synchrotron-based spot scanning proton therapy system is accurate, which is applicable for the design of patient treatment plan.
