Analysis Of Radiation Dose Distribution Inhomogenity Effects In Gamma Knife Radiosurgery Using Geant4

TL;DR

This study uses Geant4 Monte Carlo simulations to analyze how tissue inhomogeneity affects dose distribution in Gamma Knife radiosurgery, highlighting the importance of considering inhomogeneity in treatment planning.

Contribution

It applies Geant4 Monte Carlo simulations to compare dose distributions in homogeneous and heterogeneous phantoms, emphasizing the significance of inhomogeneity effects in Gamma Knife planning.

Findings

Dose differences ranged from 2% to 17% between water and brain phantoms.

Maximum dose point was at 47mm in water and 44mm in brain phantom for 4mm collimator.

Inhomogeneity effects significantly influence dose calculations in Gamma Knife radiosurgery.

Abstract

The Monte Carlo method is widely used in the Gamma Knife dose distribution calculations. In this study, Monte-Carlo simulation with Geant4 was applied to determine Leksell Gamma Knife dose distribution for homogeneous solid water and heterogeneous brain phantoms, and primarily focused on the differences arising from the effects of inhomogeneity. The relative dose graphs were displayed for different collimator diameters. The dose values from the maximal interval regions were determined and compared. It seen that when the collimator size was 4mm, the mean maximum relative dose point was at 47mm for water phantom and at 44mm for the brain. The difference found was about 6.38%. The differences among the results determined for water and brain were ranged from 2 to 17%. As a result, the inhomogeneity effect should be considered in dose calculation in Gamma Knife planning system. Keywords: Radiosurgery, Gamma Knife, {\gamma}-Rays, Inhomogeneity, Brain