Title: Dosimetric Comparison of Passive Scattering and Active Scanning Proton Therapy Techniques Using GATE Simulation Show Chinese title

Title: 使用GATE模拟的被动散射和主动扫描质子治疗技术的剂量学比较

Abstract: In this study, two proton beam delivery designs, passive scattering proton therapy (PSPT) and pencil beam scanning (PBS), were quantitatively compared in terms of dosimetric indices. The GATE Monte Carlo code was used to simulate the proton beam system; and the developed simulation engines were benchmarked with respect to the experimental measurements. A water phantom was used to simulate system energy parameters using a set of depth-dose data in the energy range of 120-235 MeV. To compare the performance of PSPT against PBS, multiple dosimetric parameters including FWHM, peak position, range, peak-to-entrance dose ratio, and dose volume histogram have been analyzed under the same conditions. Furthermore, the clinical test cases introduced by AAPM TG-119 were simulated in both beam delivery modes to compare the relevant clinical values obtained from DVH analysis. The parametric comparison in the water phantom between the two techniques revealed that the value of peak-to-entrance dose ratio in PSPT is considerably higher than that from PBS by a factor of 8%. In addition, the FWHM of the lateral beam profile in PSPT was increased by a factor of 7% compared to the corresponding value obtained from PBS model. TG-119 phantom simulations showed that the difference of PTV mean dose between PBS and PSPT techniques are up to 2.9% while the difference of max dose to organ at risks (OARs) exceeds 33%. The results demonstrated that the PBS proton therapy systems was superior in adapting to the target volume, better dose painting, and lower out-of-field dose compared to PSPT design. Show Chinese abstract

Abstract: 在本研究中，两种质子束输送设计，被动散射质子治疗（PSPT）和笔形束扫描（PBS），在剂量学指标方面进行了定量比较。 使用GATE蒙特卡罗代码对质子束系统进行了模拟；开发的模拟引擎与实验测量结果进行了基准测试。 使用水模体通过一组能量范围为120-235 MeV的深度剂量数据来模拟系统能量参数。 为了将PSPT与PBS进行性能比较，在相同条件下分析了包括FWHM、峰值位置、范围、峰值至入口剂量比和剂量体积直方图在内的多个剂量学参数。 此外，同时在两种束输送模式中模拟了AAPM TG-119引入的临床测试案例，以比较从DVH分析中获得的相关临床值。 在水模体中两种技术之间的参数比较显示，PSPT中的峰值至入口剂量比值比PBS高8%。 此外，与PBS模型得到的相应值相比，PSPT横向束流剖面的FWHM增加了7%。 TG-119模体模拟显示，PBS和PSPT技术之间的PTV平均剂量差异高达2.9%，而对危及器官（OARs）的最大剂量差异超过33%。 结果表明，与PSPT设计相比，PBS质子治疗系统在适应靶区、更好的剂量绘画和更低的场外剂量方面表现更优。