Geant4 based Dosimetry Evaluation for Gamma Knife using Different Phantom Materials

This study analyses the dose difference for a variety of phantom materials that can be used for Leksell Gamma Knife. These materials have properties that are very similar to the human tissue not including the skull bone. Geant4 was employed in the analysis the dose distributions for collimator helmet sizes of 4mm and 8mm. The phantom had a radius of 80mm. Water, brain, PMMA (Poly-methyl methacrylate) and polystyrene were used as the material types. Results showed no considerable differences for radiation dosimetries depending on the material types. In addition, the polystyrene and PMMA (Poly-methyl methacrylate) phantom are also suitable for measuring the dose profiles of the Gamma Knife unit.