Geant4中不同物理列表对硼中子俘获治疗剂量分布的影响

Geant4是基于C++编写的开源蒙特卡洛模拟软件，提供多种包含中子与物质相互作用的物理列表。本研究采用Geant4提供的几种物理列表，对沿中子束方向的总吸收剂量、硼剂量和非硼剂量深度分布进行计算，并与FLUKA进行比较，模拟中子能量从0.025 3 eV到10 MeV。对于整个模拟中子能段，结果显示添加S（α, β）热模型的高精度中子物理列表（Geant4_HP_T）在总吸收剂量、硼剂量和非硼剂量深度分布上均与FLUKA符合很好，初步验证了Genat4能应用于硼中子俘获治疗（BNCT）相关研究。对于低能中子（<1 MeV），S（α, β）热模型对BNCT剂量深度分布的影响较大，QBBC和QGSP_BERT不适用于BNCT剂量分布计算。

Effects of different Geant4 physics lists on boron neutron capture therapy dose calculation

Abstract: Geant4 is an open source Monte Carlo simulation toolkit written in C++, and it provides a variety of physical lists including neutron interactions with matter. Herein several physical lists given by Geant4 are used to calculate the depth distributions of total absorption dose, boron dose and non-Boron dose along the direction of the neutron beam, and the obtained results were compared with FLUKA. The simulation neutron energy is from 0.025 3 eV to 10 MeV. In the studied energy range, the results show that the high-precision neutron physics list (Geant4_HP_T) with S(α,β) thermal model agrees well with FLUKA in the depth distributions of total absorbed dose, boron dose and non-boron dose, which preliminarily verifies that Geant4 can be used in the researches on boron neutron capture therapy (BNCT). For low energy neutrons (<1 MeV), the S(α,β) thermal model has remarkable effects on the depth distribution of BNCT dose, and both QBBC and QGSP_BERT aren’t suitable for the calculation of BNCT dose distributions.