A Monte Carlo study of the particle angular distributions from the electron applicators of a medical linear accelerator

Abstract

Accurate calculation of the absorbed dose distribution in patients irradiated by clinical electron beams is very important in radiotherapy treatment. Currently, the most accurate method of radiation therapy dose calculation is provided by the Monte Carlo (MC) simulation of the radiation transport. The aim of this study was to investigate and determine the particles angular distributions from the diaphragm applicators of a medical linear accelerator (Neptun 10PC) using MC method. The linac electron beams (6, 8, an 10 MeV) were modeled using the BEAMnrc MC system based on the EGSnrc code. The geometry of the linac treatment head was modeled. The MC phase space recorded files were analyzed with the BEAMDP program in order to determine the particles angular distributions. The results indicated that the direction of the particles emerged from the linac trimmer applicators are mostly in forward direction for all the linac electron beams. © 2009 Springer-Verlag.