浅层X射线治疗机过滤器对放疗剂量学影响的蒙特卡罗模拟研究  

Monte Carlo simulation study of the effect of filter on radiotherapy dosimetry in superficial X-ray therapy apparatus

作　　者：陶莉 张慧 吴翊凯[1] 刘君怡 齐妙 高宁 常艳奎 裴曦 陈志 徐榭[1] Tao Li;Zhang Hui;Wu Yikai;Liu Junyi;Qi Miao;Gao Ning;Chang Yankui;Pei Xi;Chen Zhi;Xu Xie(School of Nuclear Science and Technology,University of Science and Technology of China,Hefei 230025,China;Department of Radiotherapy,First Affiliated Hospital of USTC,Hefei 230031,China;Anhui Wisdom Technology Co.Ltd,Hefei 230088,China)

机构地区：[1]中国科学技术大学核科学技术学院,合肥230025 [2]中国科学技术大学附属第一医院放疗科,合肥230031 [3]安徽慧软科技有限公司,合肥230088

出　　处：《中华放射医学与防护杂志》2025年第3期194-201,共8页Chinese Journal of Radiological Medicine and Protection

基　　金：安徽省重点研究与开发计划(2023s07020020);国家自然科学基金项目(12275372);中国科学技术大学双一流医学物理与生物医学工程交叉学科平台(YD2140000601);2020年中科大新医学创新团队项目(YD2140002002)。

摘　　要：目的探索针对使用X射线管的浅层放射治疗机基于过滤器厚度和形状选择的剂量学优化策略。方法使用蒙特卡罗代码TOPAS对X射线管配套设备建模,在水模体中模拟6种X射线能量(50~150 kV)以及5种不同厚度的常规铝过滤器(0.5~3.0 mm)的剂量分布,分析了沿中心轴的百分比深度剂量(PDD)曲线、不同深度的中心轴剖面二维剂量以及横向剂量曲线。同时,对比了3种不同设计的铝制过滤器(常规圆柱形、圆锥形和斜柱形过滤器)的剂量分布,以评估不同过滤器形状的剂量学优化的效果。结果在同一能量下,增加过滤器厚度可以优化浅表皮肤剂量,70 kV能量下深度剂量均匀性优化效果在5.5 mm深处最大能提高26%。应用常规圆柱形、锥形和斜柱形的铝过滤器,能够分别实现凸起、平坦和倾斜的剂量分布模式。结论通过合理选择X射线能量和过滤器厚度,可以获得与靶区深度相匹配的理想剂量分布;引入个性化过滤器对于多样性靶区目标也具有重要意义。Objective To explore the dosimetry optimization strategy based on filter thickness and shape selection for the bulb superficial X-ray radiotherapy unit.Methods Monte Carlo code TOPAS was used to model tubular equipment,and the dose distribution from six X-ray energies(50-150 kV)and five conventional aluminum filters(0.5-3.0 mm)with different thickness were simulated in the water model.The percentage depth dose(PDD)curve along the central axis,the center-axis profile dose at different depths,and the lateral dose distribution were analyzed.The dose distribution of three different designs of aluminum filters(conventional cylindrical,conical and oblique cylindrical filters)was compared to evaluate the effect of dosimetric optimization of different filter shapes.Results Under the same energy,increasing the thickness of the filter can optimize the superficial skin dose,and the optimization effect of depth dose uniformity can be increased by 26%at a depth of 5.5 mm at 70 kV energy.The raised,flat and inclined dose distribution modes can be achieved by using conventional cylindrical,conical and inclined aluminum filters.Conclusions By selecting the appropriate X-ray energy and filter thickness,an ideal dose distribution matching the tumor depth can be achieved.The application of personalized filters is also of great significance for diverse target areas.

关 键 词：浅层X射线放疗 过滤器 蒙特卡罗模拟 剂量优化 

分 类 号：R73[医药卫生—肿瘤]