A standardized commissioning framework of Monte Carlo dose calculation algorithms for proton pencil beam scanning treatment planning systems
A standardized commissioning framework of Monte Carlo dose calculation algorithms for proton pencil beam scanning treatment planning systems
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DOI：
10.1002/mp.14021
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发表时间：
2020-02-04
期刊：
影响因子：
3.8
通讯作者：
Lin, Liyong
中科院分区：
文献类型：
--
作者：
Chang, Chih-Wei;Huang, Sheng;Lin, Liyong
不同供应商的治疗计划系统（TPS）可能涉及笔形束扫描（PBS）质子治疗的蒙特卡罗剂量计算（MCDC）算法的不同实现。目前没有验证TPS中非水材料的指南。此外，在不同的治疗递送系统（TDS）之间，PBS特异性参数可以变化1 - 2个数量级。本文提出了一个标准化的框架使用的调试数据和步骤，以验证TDS特定的参数和TPS特定的异质性建模，以潜在地减少这些uncertaints.Methods开发了一个标准化的调试框架，以委托MCDC算法的RayStation 8A和Eclipse AcurosPT v13.7.20使用水和非水材料。测量包括Varian ProBeam的布拉格峰值深度剂量和横向光斑轮廓以及扫描场输出。相空间参数从空气中测量获得，每MU的质子数从2 cm深度的10 x 10 cm（2）平方场的输出测量获得。在其他深度的光斑轮廓和各种PBS场测量用于验证TPS。TPS中的人体组织，Gammex体模材料，和人工材料被用于TPS基准和validation.Results的相位参数，斑点sigma，和发散MCDC算法之间的最大差异是低于4.5 μ m和0.26 mrad的空气中，分别。将TPS与深度处的测量值进行比较，两种MC算法都预测了0.5 mm不确定性区间（测量设备的分辨率）内的点sigma。发现AcurosPT中的射束配置低估了每MU的质子数，约为2.5%，需要用户调整以匹配测量数据，而RayStation在使用Auto模型测量的1%范围内。一个固体水模被用来验证范围内的精度在1% AcurosPT.Conclusions的非水材料的标准化调试框架可以检测到潜在的问题，在PBS TPS MCDC调试过程中，并有可能缩短调试时间，提高剂量准确性。次级MCDC可用于识别初级MCDC和测量之间不一致的根源。
Purpose Treatment planning systems (TPSs) from different vendors can involve different implementations of Monte Carlo dose calculation (MCDC) algorithms for pencil beam scanning (PBS) proton therapy. There are currently no guidelines for validating non-water materials in TPSs. Furthermore, PBS-specific parameters can vary by 1-2 orders of magnitude among different treatment delivery systems (TDSs). This paper proposes a standardized framework on the use of commissioning data and steps to validate TDS-specific parameters and TPS-specific heterogeneity modeling to potentially reduce these uncertainties.Methods A standardized commissioning framework was developed to commission the MCDC algorithms of RayStation 8A and Eclipse AcurosPT v13.7.20 using water and non-water materials. Measurements included Bragg peak depth-dose and lateral spot profiles and scanning field outputs for Varian ProBeam. The phase-space parameters were obtained from in-air measurements and the number of protons per MU from output measurements of 10 x 10 cm(2) square fields at a 2 cm depth. Spot profiles and various PBS field measurements at additional depths were used to validate TPS. Human tissues in TPS, Gammex phantom materials, and artificial materials were used for the TPS benchmark and validation.Results The maximum differences of phase parameters, spot sigma, and divergence between MCDC algorithms are below 4.5 mu m and 0.26 mrad in air, respectively. Comparing TPS to measurements at depths, both MC algorithms predict the spot sigma within 0.5 mm uncertainty intervals, the resolution of the measurement device. Beam Configuration in AcurosPT is found to underestimate number of protons per MU by similar to 2.5% and requires user adjustment to match measured data, while RayStation is within 1% of measurements using Auto model. A solid water phantom was used to validate the range accuracy of non-water materials within 1% in AcurosPT.Conclusions The proposed standardized commissioning framework can detect potential issues during PBS TPS MCDC commissioning processes, and potentially can shorten commissioning time and improve dosimetric accuracies. Secondary MCDC can be used to identify the root sources of disagreement between primary MCDC and measurement.