The findings were compared with the corresponding experimental results. MATERIALS AND MEK activity METHODS Software and hardware requirements for this study were as follows: Hardware Requirements The 6 MV photon beam used
in this study, was delivered by Elekta linear accelerator. Dosimetry was performed according to TG-51 protocol. To collect data, a water phantom as well as a diode detector (Wellhoffer – Scanditronix, Schwarzenbruck, Germany) was applied. In order to accelerate the simulation calculations, the parallel computing technique was used on 9 computers (Intel (R) core (TM) 2 Duo CPU with 2.93 GHz, 2GB RAM). Software Requirements On the way to perform the simulation, GEANT4 and GATE codes were used (versions 4.9.3 and 6.1, respectively).
In order to store/analyze the data during particle simulation, ROOT version 5.27.4, which is an object-oriented data analysis framework, was used. To view and verify the geometry implementation, graphical interfaces, which are available in GEANT4/GATE, were applied. These interfaces were as follows: WIRED 3, VRML viewer 4.0, and DAWN version 3_88. The operating systems used in the study were Fedorc core 13 and CentOs, version 6.0. For parallel computing and clustering, Condor (platform) version 7.2.4 was used. Geometrical Implementation of Compact Linear Accelerator System Physical characteristics (shape, geometric dimensions and the material of constituent elements) of the original compact linear accelerator treatment head was defined in the GATE Code, which included the target: Made of tungsten alloy, about 0.2 cm thickness,
the primary collimator: Made of tungsten, 10.2 cm height, located below the X-ray target used to collimate the X-ray in the direction of the treatment field, the flattening filter: Made of stainless steel and conical shape and its height is 17.5 mm and 2 mm in the middle and corner, respectively, the ionization chamber, a 60-degree universal wedge, and the secondary collimators: Are made of tungsten alloy about 10 cm thickness. Figure 1 is the view of the linear accelerator system simulation. Figure 1 The view of the linear accelerator system The Definition of Electron Source For defining the Brefeldin_A electron beam incident on the target of linear accelerator system, the general particle source module was used. This module provides an opportunity to define and implement parameters such as spatial and angular distributions and the energy spectrum of the electron beam. Trial and error method was used to determine these parameters. After setting these parameters, the dose distributions, calculated in the water phantom, were compared with the experimental data using the gamma index method with 3%/3 mm criteria. The Definition of Physical Interactions The exact implementation of a system like LINAC requires the simulation of all physical events, which occur in the real world.