Dowlatabadi H, Mowlavi A A, Ghorbani M, Mohammadi S, Akbari F
Physics Department, School of Sciences, Payame Noor University of Mashhad, Mashhad, Iran.
Physics Department, School of Sciences, Hakim Sabzevari University, Sabzevar, Iran.
J Biomed Phys Eng. 2018 Jun 1;8(2):157-166. eCollection 2018 Jun.
Radiation therapy using electron beams is a promising method due to its physical dose distribution. Monte Carlo (MC) code is the best and most accurate technique for forespeaking the distribution of dose in radiation treatment of patients.
We report an MC simulation of a linac head and depth dose on central axis, along with profile calculations. The purpose of the present research is to carefully analyze the application of MC methods for the calculation of dosimetric parameters for electron beams with energies of 8-14 MeV at a Siemens Primus linac. The principal components of the linac head were simulated using MCNPX code for different applicators.
The consequences of measurements and simulations revealed a good agreement. Gamma index values were below 1 for most points, for all energy values and all applicators in percent depth dose and dose profile computations. A number of states exhibited rather large gamma indices; these points were located at the tail of the percent depth dose graph; these points were less used in in radiotherapy. In the dose profile graph, gamma indices of most parts were below 1. The discrepancies between the simulation results and measurements in terms of Z, R, R and R were insignificant. The results of Monte Carlo simulations showed a good agreement with the measurements.
The software can be used for simulating electron modes of a Siemens Primus linac when direct experimental measurements are not feasible.
由于其物理剂量分布，使用电子束的放射治疗是一种很有前景的方法。蒙特卡罗（MC）代码是预测患者放射治疗中剂量分布的最佳且最准确的技术。
我们报告了直线加速器头部及中心轴深度剂量的蒙特卡罗模拟，以及剖面计算。本研究的目的是仔细分析蒙特卡罗方法在西门子Primus直线加速器上计算8 - 14 MeV能量电子束剂量学参数的应用。使用MCNPX代码针对不同的施源器对直线加速器头部的主要部件进行了模拟。
测量和模拟结果显示出良好的一致性。在百分深度剂量和剂量剖面计算中，对于所有能量值和所有施源器，大多数点的伽马指数值均低于1。有一些情况显示出相当大的伽马指数；这些点位于百分深度剂量图的尾部；这些点在放射治疗中较少使用。在剂量剖面图中，大多数部分的伽马指数低于1。模拟结果与测量结果在Z、R、R和R方面的差异不显著。蒙特卡罗模拟结果与测量结果显示出良好的一致性。
当直接实验测量不可行时，该软件可用于模拟西门子Primus直线加速器的电子模式。
