Eur. Phys. J. Plus (2015) 130: 150
https://doi.org/10.1140/epjp/i2015-15150-1

Regular Article

Varian 2100C/D Clinac 18 MV photon phase space file characterization and modeling by using MCNP Code

Faculty of Physics, University of Tabriz, Tabriz, Iran

^* e-mail: ah_ezzati63@yahoo.com

Received: 26 January 2015
Revised: 25 April 2015
Accepted: 2 July 2015
Published online: 28 July 2015

Abstract

Multiple points and a spatial mesh based surface source model (MPSMBSS) was generated for 18MV Varian 2100 C/D Clinac phase space file (PSF) and implemented in MCNP code. The generated source model (SM) was benchmarked against PSF and measurements. PDDs and profiles were calculated using the SM and original PSF for different field sizes from 5 × 5 to 20 × 20 cm². Agreement was within 2% of the maximum dose at 100cm SSD for beam profiles at the depths of 4cm and 15cm with respect to the original PSF. Differences between measured and calculated points were less than 2% of the maximum dose or 2mm distance to agreement (DTA) at 100 cm SSD. Thus it can be concluded that the modified MCNP code can be used for radiotherapy calculations including multiple source model (MSM) and using the source biasing capability of MPSMBSS can increase the simulation speed up to 3600 for field sizes smaller than 5 × 5 cm².