To provide a practical guide on the selection of Monte Carlo (MC) dose calculation parameters for scanned beam proton therapy in RayStation, we generated treatment plans with various combinations of two MC dose calculation parameters in the optimization and compared the elapsed time and dosimetric properties of those plans. We selected 23 clinical cases treated with scanned beam proton therapy. For each clinically approved treatment plan, we generated 26 exploring plans (1 plan with clinical pencil beam dose algorithm and 25 plans with MC dose algorithm with varying dose calculation parameters). We recorded the elapsed time for individual plans in the dose calculation using an automated RayStation script. To evaluate the dosimetric quality of the exploring plans, the conformity and homogeneity indices of each plan were calculated and dose–volume histograms for the target volume and organs-at-risk were assessed. We found the combination of 12,000 ions/spot in the optimization and 0.5% uncertainty in the final dose calculation would provide a dosimetrically competent plan with a reasonable amount of dose calculation time. We would suggest using 8000 ions/spot in the optimization and 1.0% uncertainty in the final dose calculation as a starting point in the treatment planning of scanned beam proton therapy. The practical recommendations resulting from this study, related to MC dose calculations, have the potential to enhance treatment planning strategies for scanned beam proton therapy and to make the iterative process of treatment planning more efficient.

为了为 RayStation 中扫描束质子治疗的蒙特卡罗 (MC) 剂量计算参数的选择提供实用指南，我们在优化中使用两个 MC 剂量计算参数的各种组合生成了治疗计划，并比较了经过的时间和剂量学特性。那些计划。我们选取了23例接受扫描束质子治疗的临床病例。对于每个临床批准的治疗计划，我们生成了 26 个探索计划（1 个计划采用临床笔形束剂量算法，25 个计划采用 MC 剂量算法，并具有不同的剂量计算参数）。我们使用自动化 RayStation 脚本记录了剂量计算中各个计划所用的时间。为了评估探索计划的剂量测定质量，计算每个计划的一致性和均匀性指数，并评估目标体积和风险器官的剂量体积直方图。我们发现优化中 12,000 个离子/点的组合和最终剂量计算中 0.5% 的不确定性将提供具有合理剂量计算时间的剂量测定计划。我们建议在优化中使用 8000 个离子/点，并在最终剂量计算中使用 1.0% 的不确定性，作为扫描束质子治疗治疗计划的起点。这项研究得出的与 MC 剂量计算相关的实用建议有可能增强扫描束质子治疗的治疗计划策略，并使治疗计划的迭代过程更加高效。