The Study of Incident Electron Beam Parameters of XHA600D Medical Linear Accelerator Based on Monte Carlo Method

This study investigated the influence of incident electron beam parameters on dose distribution generated by the XHA600D accelerator based on Monte Carlo method, and then determined the optimal incident electron beam parameters. According to the geometric and material parameters of XHA600D accelerator treatment head provided by the manufacturer, the dose distributions in the water phantom generated by different incident electron beam parameters were simulated and recorded using Monte Carlo code EGSnrc, and the simulated dose distributions were compared with the measured results. The simulated incident electron beam parameters include mean energy, radial intensity distribution, angular divergency and energy spread. The experimental measurements include percentage depth doses and off-axis doses for 4 cm×4 cm, 10 cm×10 cm, 30 cm×30 cm fields. The results show that the simulated data are in excellent agreement with the measurements when the mean energy is monoenergetic 6 MeV, the FWHM(Full Width at Half Maximum) radial intensity is 0.25 cm and the angular divergency is 0.15°. These parameters can be used as the basic parameters to establish the dose calculation model of TPS(Treatment Planning System) for XHA600D accelerator.