Comparison of Electron-Beam Dose Distributions in a Heterogeneous Phantom Obtained Using Radiochromic Film Dosimetry and Monte Carlo Simulation

Nowadays new radiochromic films have an essential role in radiotherapy dosimetry. Properties such as high sensitivity, good reproducibility, high spatial resolution, easy readout and portability have made them attractive for dosimetry, especially in high-dose-gradient regions. In this study, electron-beam dose distributions in homogenous and heterogeneous phantoms were calculated using the MCNPX Monte Carlo code and compared with experimental measurements obtained by GAFCHROMIC® EBT film and p-type silicon diode dosimetry. Irradiation was carried out using an Elekta linear accelerator at two different electron energies (8 and 15 MeV), with a 10×10 cm2 applicator and at 100 cm source-to-surface distance. The results show good agreement (within 2%) between radiochromic film measurements and MCNP results. The results show that the new radiochromic films can be used in electron dosimetry and that they are also reliable in presence of heterogeneous media.