螺旋断层放疗的快速蒙特卡罗剂量验证模块开发  

Development of a fast Monte Carlo dose verification module for helical tomotherapy

作　　者：李仕军 高宁 程博 皮一飞 王海洋 常艳奎[1] 裴曦 徐榭 LI Shijun;GAO Ning;CHENG Bo;PI Yifei;WANG Haiyang;CHANG Yankui;PEI Xi;Xie George XU(School of Nuclear Science and Technology,University of Science and Technology of China,Hefei 230026,China;Department of Radiotherapy,the First Affiliated Hospital of Zhengzhou University,Zhengzhou 450052,China;Anhui Wisdom Technology Co..Ltd.,Hefei 238000,China;Department of Radiotherapy,the First Affiliated Hospital of University of Science and Technology of China,Hefei 230001,China)

机构地区：[1]中国科学技术大学核科学技术学院,安徽合肥230026 [2]郑州大学第一附属医院放射治疗部,河南郑州450052 [3]安徽慧软科技有限公司,安徽合肥238000 [4]中国科学技术大学附属第一医院放疗科,安徽合肥230001

出　　处：《中国医学物理学杂志》2024年第11期1321-1326,共6页Chinese Journal of Medical Physics

基　　金：国家自然科学基金(12275372);安徽省重点研究与开发计划(2023s07020020);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年中国科学技术大学新医学创新团队项目(YD2140002002)。

摘　　要：目的:开发用于螺旋断层放疗(TOMO)的基于GPU加速蒙特卡罗独立剂量验证模块,并将其集成到商业软件Archer QA,应用于临床。方法:首先,采用TOPAS构建TOMO治疗头模型,并获得相空间文件;然后,使用一种快速的透射粒子权重调制算法来模拟粒子在多叶准直器中的输运,以提高计算效率;最后,调用Archer QA里基于GPU加速的蒙特卡罗算法来模拟粒子在患者体内的输运。为验证模型的准确性,比较水箱中不同开野条件下Archer QA计算剂量与测量剂量的差异。此外,选取15例临床病例,其中头颈部、胸腹部、全身各5例,对比Archer QA计算剂量、治疗计划系统(TPS)计算剂量和Arc CHECK测量剂量两两之间的差异。结果:在开野为40 cm×5.0 cm、40 cm×2.5 cm、40 cm×1.0 cm的水箱测试中,Archer QA计算的百分深度剂量、横向剂量分布、纵向剂量分布与对应测量值的平均全局相对误差分别为0.72%、0.66%、0.54%,98%以上体素全局相对误差小于1%。对于15例临床病例,在2%/2 mm的标准下,Archer QA与TPS的平均Gamma通过率为98.1%。相同标准下,Archer QA与Arc CHECK测量值的平均Gamma通过率为99.4%,TPS与Arc CHECK测量值的平均Gamma通过率为99.1%。所有病例模拟的统计误差均小于1%,基于患者CT计算的平均时间为87 s,基于Arc CHECK模体计算的平均时间为64 s。结论:Archer QA能提供快速且准确的剂量计算,可用于TOMO计划的独立剂量验证。Objective To develop a GPU-based Monte Carlo dose calculation module for helical tomotherapy (TOMO),and integrate it into the commercial software Archer QA to achieve fast and accurate dose verification in clinic.Methods The TOMO treatment head was modeled using TOPAS to obtain phase space files,and a fast weight tuning algorithm was used to simulate particle transport in multi-leaf collimator for improving computational efficiency,and finally,GPU-based Monte Carlo algorithms in Archer QA were used to simulate particle transport in patients.To verify the model accuracy,the Archer QA calculated results in water tank were compared with measured data for different open fields.In addition,multiple comparisons among Archer QA results,TPS results and Arc CHECK results were conducted on 15 clinical cases (5 cases in the head and neck,5 cases in the chest and abdomen,and 5 cases in the whole body).Results In the water tank tests for 40 cm×5.0 cm,40 cm×2.5 cm and 40 cm×1.0 cm radiation fields,the average global relative errors of the percentage depth dose,transverse dose distribution,and longitudinal dose distribution calculated by Archer QA with the corresponding measured values were0.72%,0.66%,and 0.54%,respectively.Over 98%of the voxels had a global relative error of less than 1%.As for 15 clinical cases,in 2%/2 mm criteria,the mean Gamma passing rate was 98.1%between Archer QA and TPS,99.1%between TPS and Arc CHECK,and 99.4%between Archer QA and Arc CHECK.The uncertainty of the simulation maintained less than 1%,and the average time taken for calculation based on patient CT vs Arc CHECK phantom was 87 s vs 64 s.Conclusion Archer QA can be used for independent dose validation for TOMO plans for it can provide fast and accurate dose calculations.

关 键 词：螺旋断层放疗 蒙特卡罗 剂量验证 ArcherQA 

分 类 号：R318[医药卫生—生物医学工程] R811.1[医药卫生—基础医学]