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  

Clinical commissioning of Monte Carlo algorithm for synchrotron-based spot scanning proton therapy system

作　　者：陈媚 闫渊林 周晖 蒋徐铭 张毅斌[1,2] 贺晓东 曹璐 陈志凌[2,3] 张满洲 许赪 陈佳艺 Chen Mei;Yan Yuanlin;Zhou Hui;Jiang Xuming;Zhang Yibin;He Xiaodong;Cao Lu;Chen Zhiling;Zhang Manzhou;Xu Cheng;Chen Jiayi(Department of Radiation Oncology,Ruijin Hospital Shanghai Jiao Tong University School of Medicine,Shanghai 200025,China;Shanghai Key Laboratory of Proton Therapy,Shanghai 201801,China;Shanghai Apactron Particle Equipment Co.Ltd,Shanghai 201801,China)

机构地区：[1]上海交通大学医学院附属瑞金医院放射治疗科,上海200025 [2]上海市质子治疗转化研究重点实验室,上海201801 [3]上海艾普强粒子设备有限公司,上海201801

出　　处：《中华放射肿瘤学杂志》2025年第3期275-281,共7页Chinese Journal of Radiation Oncology

基　　金：上海市“科技创新行动计划”医学创新研究专项项目(23Y41900100);市级医院诊疗技术推广及优化管理项目(SHDC12023108);国家自然科学基金(82373514,82373202)。

摘　　要：目的介绍RayStation治疗计划系统用于国产自主研发的同步加速器质子点扫描治疗系统SAPT-PS-01的蒙特卡罗剂量计算算法的临床建模和调试结果。方法构建RayStation的质子笔形线束模型需要输入三项束流参数,分别为积分深度剂量曲线、束斑剖面曲线和绝对剂量刻度,不需要单独采集带射程移位器的束流参数。用半径为8 cm的平行板电离室在水模体里测得单个质子束斑的积分深度剂量曲线;运用闪烁体平板探测器采集了包括等中心平面在内的空气中5个深度处束斑剖面曲线;绝对剂量刻度方案为采用半径为0.25 cm的平行板电离室测量单能10 cm×10 cm方野的等中心点剂量。建模完成后,分别从射程计算、空气中和水中单个束斑剖面曲线、展宽布拉格峰中心轴点剂量、临床病例二维剂量分布、仿真模体端对端测试5个方面对治疗计划系统蒙特卡罗剂量计算结果进行验证。结果针对SAPT-PS-01质子治疗系统的94个能量的射程建模,最大偏差为0.03 cm,空气中的束斑大小计算值与实测值的最大偏差为0.015 cm,有无射程移位器的情境下水中束斑大小偏差均<15%。与测量值相比,水中展宽布拉格峰138个测量点的计算剂量偏差<3%,285个临床病例二维剂量分布的3%/3 mm标准下的γ通过率均>90%,近95%的平面通过率>95%。端对端测试的4个临床场景,8个射野的点剂量计算偏差<5%。结论束流模型验证结果均在可接受的容差范围内,证明了RayStation中基于同步加速器的SAPT-PS-01质子点扫描治疗系统束流模型及蒙特卡罗剂量计算算法的准确性,可用于患者治疗计划设计。ObjectiveTo 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).MethodsThe 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.ResultsFor 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%.ConclusionsThe 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

关 键 词：同步加速器 质子点扫描治疗系统 蒙特卡罗算法 临床调试 

分 类 号：TP3[自动化与计算机技术—计算机科学与技术]