蒙特卡罗模拟中物理模型对质子硼俘获治疗剂量学的影响

Effect of different physics lists in Monte Carlo simulation on proton boron capture therapy

  • 摘要: 比较了蒙特卡罗(MC)软件Geant4中不同物理过程对质子硼俘获治疗(PBCT)的剂量学影响。选取Geant4中FTFP、QBBC和QGSP三种物理过程,构建包含质子硼核反应的质子剂量沉积的模型,比较了80 MeV质子束选取三种物理过程在有无硼时的剂量分布,以及3 MeV质子束轰击纯硼时的核反应产物数据。三种物理过程在有无硼时水模体中的剂量分布无显著差异,一致性较好。FTFP物理过程获得的质子硼核反应产物与QBBC和QGSP物理过程相比差异较大。而QGSP物理过程得到的α粒子的产额、平均能量和能量范围与QBBC物理过程相比与实际情况吻合更好。综合评估三种物理过程中使用的非弹性散射模型以及模拟得到的核反应产物数据,Geant4中的QGSP物理过程更适用于PBCT的MC模拟研究。

     

    Abstract: This paper compares the effects of different physics lists on the dose of proton boron capture therapy (PBCT) in Monte Carlo Geant4 simulation. Geant4 was used to establish PBCT model with three different physics lists (FTFP, QBBC and QGSP). Comparison is made for dose distribution of three physics lists with and without boron using an 80 MeV proton beam, as well as the nuclear reaction product data of a 3 MeV proton beam bombarding pure boron. There is no significant difference in the dose distribution of the three physics lists in the water phantom with and without boron, and the consistency of different physics models’ percentage depth dose (PDD) curves is good. The PBCT nuclear reaction products obtained from FTFP physics list are significantly less than those obtained from QBBC and QGSP physics lists. The yields, mean energies and energy ranges of the alpha particles obtained from the QGSP physics list are more consistent with the actual situation than that of the QBBC physics list. The QGSP physics list in Geant4 is more suitable for MC simulation studies of PBCT, judging by a comprehensive evaluation of the inelastic scattering models used by the three physics lists and the simulated nuclear reaction data.

     

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