Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan.
Phys Med Biol. 2010 Jun 21;55(12):3545-56. doi: 10.1088/0031-9155/55/12/018. Epub 2010 May 28.
Treatment planning for proton tumor therapy requires a fast and accurate dose-calculation method. We have implemented a simplified Monte Carlo (SMC) method in the treatment planning system of the National Cancer Center Hospital East for the double-scattering beam delivery scheme. The SMC method takes into account the scattering effect in materials more accurately than the pencil beam algorithm by tracking individual proton paths. We confirmed that the SMC method reproduced measured dose distributions in a heterogeneous slab phantom better than the pencil beam method. When applied to a complex anthropomorphic phantom, the SMC method reproduced the measured dose distribution well, satisfying an accuracy tolerance of 3 mm and 3% in the gamma index analysis. The SMC method required approximately 30 min to complete the calculation over a target volume of 500 cc, much less than the time required for the full Monte Carlo calculation. The SMC method is a candidate for a practical calculation technique with sufficient accuracy for clinical application.
质子肿瘤治疗的计划需要一种快速而准确的剂量计算方法。我们在国立癌症中心医院东的治疗计划系统中为双散射束输送方案实现了简化的蒙特卡罗（SMC）方法。SMC 方法通过跟踪单个质子路径，比铅笔束算法更能准确地考虑材料中的散射效应。我们确认 SMC 方法比铅笔束算法更好地再现了不均匀平板体模中的测量剂量分布。当应用于复杂的拟人体体模时，SMC 方法很好地再现了测量的剂量分布，满足伽马指数分析中 3 毫米和 3%的精度容限。SMC 方法完成 500cc 目标体积的计算大约需要 30 分钟，远小于全蒙特卡罗计算所需的时间。SMC 方法是一种具有足够临床应用精度的实用计算技术的候选方法。
