MC法模拟质子治疗中靶区定位

Target Location in Proton Therapy:A Monte Carlo study

本文利用MCNPX程序模拟了质子束入射靶区的输运过程。通过^(16)O(p,α^(13)N、^(13)N的β^+衰变、e^++e^-→2γ,得到湮灭光子分布,确定靶区位置与Bragg峰深度的关系。模拟结果显示,能量为60MeV^150 MeV的质子入射肌肉组织模体时,湮灭光子通量下降梯度最大的位置为Bragg峰位置,位置偏差<2%;当90 MeV质子入射含GTV(肿瘤靶区)的肌肉组织模体时,Bragg峰位置发生移动,此时湮灭光子通量下降梯度最大的位置与Bragg峰位置相同,位置偏差<1%。利用MC法确定靶区位置,更接近理想位置。

The Monte Carlo MCNPX program is used to simulate the transport process of proton beam incident the target region. The annihilation photon distribution is obtained by the reaction of^16 O （ p, α） ^13N, ^13N β ＋ decay and e^＋ ＋ e^-→ 2γ to determine the relationship between the target position and the depth of Bragg peak. The simulation results show that when the energy of 60 MeV - 150 MeV proton enters the muscle phantom,the position of the highest photon flux declining is Bragg peak position, the error is less than 2% ; when the 90 MeV proton enters the muscle containing GTV,The position of Bragg peak shifted . At the same time, the position of the highest photon flux declining is Bragg peak position, the error is less than 1% ; The target location which uses the method of Monte Carlo to determine is closer the ideal value.