基于临床质子加速器的DeepPlan笔形束模型构建

目的:基于佛罗里达大学质子放疗中心（University of Florida Health Proton Therapy Institute, UFHPTI）质子加速器在笔形束扫描模式下的临床实验数据，在DeepPlan中构建相应模型，验证模型构建的准确性并初步应用于临床前列腺癌的剂量计算。方法:在DeepPlan质子模块中建立UFHPTI质子加速器的笔形束计算模型，并将剂量计算结果与临床实验数据进行对比，包括30组积分深度剂量（Integrated Depth Dose, IDD）、30组空气中质子束斑发散大小、1组多能量多点照射下的纵向扩展布拉格峰（Spread Out Bragg Peak, SOBP）和横向剂量分布，以此验证模型构建的准确性。最后以UFHPTI的两个前列腺癌临床放疗计划为指导，将DeepPlan计算结果与商用放疗计划系统RayStation计算结果通过PTW公司的VeriSoft软件进行gamma分析。结果:DeepPlan质子模块计算产生的30组IDD与UFHPTI加速器的临床实验数据平均相对误差为0.01%，最大相对误差为0.23%；30组空气质子束斑发散大小与临床实验数据平均相对误差为0.15%，最大相对误差为1.14%。在多能量多点照射下，DeepPlan质子模块计算产生的SOBP与临床实验数据平均相对误差为1.07%，最大相对误差为3.91%；横向剂量分布和临床实验数据平均相对误差为1.92%，最大相对误差为4.09%。针对两个前列腺癌的放疗计划，DeepPlan质子模块与RayStation计算的三维剂量结果在以3 mm/3%的标准下每个子野的gamma通过率都达到95%以上，其中病例1两个子野（270°和90°方向）的gamma通过率分别为96.4%和97.5%，病例2两个子野（270°和90°方向）的gamma通过率分别为99.3%和98.9%。结论:在DeepPlan中构建了与UFHPTI质子加速器相匹配的笔形束模型，该模型可初步应用于临床前列腺癌的剂量计算。

Construction of pencil beam model in DeepPlan based on clinical proton accelerator

Objective Based on the clinical experimental data of University of Florida Health Proton Therapy Institute(UFHPTI)proton accelerator in the pencil beam scanning mode,a corresponding model is constructed in DeepPlan to verify the accuracy of model construction,and the model is preliminarily applied to the dose calculation of prostate cancer.Methods The pencil beam calculation model of UFHPTI proton accelerator was established in DeepPlan proton module.The results of dose calculation were compared with clinical experimental data,including 30 groups of integrated depth dose,30 groups of proton beam spot divergence in the air,and a set of longitudinal spread out Bragg peak and transverse dose distribution under multi-energy and multi-point irradiation,so as to verify the accuracy of model construction.Finally,guided by the clinical radiotherapy plans of 2 cases of prostatic cancer in UFHPTI,the calculation results of DeepPlan and those of commercial radiotherapy planning system RayStation were analyzed by VeriSoft software of PTW for gamma analysis.Results The average relative error of 30 groups of integrated depth dose between clinical experimental data of UFHPTI accelerator and those calculated by DeepPlan proton module was 0.01%,with the maximum relative error of 0.23%.The average relative error of 30 groups of proton beam spot divergence in the air between the calculated results of DeepPlan proton module and clinical experimental data was 0.15%,with the maximum relative error of 1.14%.Under multi-energy and multi-point irradiation,the average relative error of spread out Bragg peak calculated by DeepPlan proton module and clinical experimental data was 1.07%,with the maximum relative error of 3.91%;and the average relative error of transverse dose distribution calculated by DeepPlan proton module and clinical experimental data was 1.92%,with the maximum relative error of 4.09%.For the radiotherapy plans of 2 cases of prostate cancer,the three-dimensional doses calculated by DeepPlan proton module and RayStation reached a gamma passing rate of more than 95%for each subfield under the criterion of 3mm/3%.The gamma passing rates of two subfields(270°and 90°)in case 1 were 96.4%and 97.5%,and those of two subfields(270°and 90°)in case 2 were 99.3%and 98.9%.Conclusion A pencil beam model matching with UFHPTI proton accelerator is constructed in DeepPlan,and the constructed model can be preliminarily applied to the dose calculation of prostate cancer.