横向均匀磁场对高能电子束剂量分布影响的蒙特卡罗研究

Study of the Influence of Uniform Transverse Magnetic Field on the Dose Distribution of High Energy Electron Beam Using Monte Carlo Method

本文采用蒙特卡罗方法研究了横向均匀磁场下,高能电子束在均匀水模中的剂量分布特点。结果显示磁场对电子束剂量分布产生了明显影响。这些影响包括电子束的射程明显降低且在射程末端形成很高的剂量峰值,并随后产生迅速的剂量跌落。此外,峰值与表面剂量比值也大幅增加。模拟结果表明,适当的磁场和电子线能量可以产生类似于重离子的深度剂量分布特性,这意味着磁场条件下的电子线放疗具有相当大的应用前景,但同时为相应的剂量算法研究带来了新的挑战。

In the present work, Monte Carlo simulations were employed to study the characteristics of the dose distri- bution of high energy electron beam in the presence of uniform transverse magnetic field. The simulations carried out the transport processes of the 30 MeV electron beam in the homogeneous water phantom with different magnetic field. It was found that the dose distribution of the 30 MeV electron beam had changed significantly because of the magnetic field. The result showed that the range of the electron beam was decreased obviously and it formed a very high dose peak at the end of the range, and the ratio of maximum dose to the dose of the surface was greatly in- creased. The results of this study demonstrated that we could change the depth dose distribution of electron beam which is analogous to the heavy ion by modulating the energy of the electron and magnetic field. It means that using magnetic fields in conjunction with electron radiation therapy has great application prospect, but it also has brought new challenges for the research of dose algorithm.