Monte Carlo simulation of the lateral spread for proton beams in voxelized water phantom using GEANT4 platform

An evaluation of the lateral spread that the proton beams undergo during their interactions with a water phantom has been performed. We calculated and evaluated the dose distribution spatially deposed of protons acceleration up to energies between 70 and 215 MeV using a voxelized water phantom as a 3D detector. A 0.1 mm 3 size precision voxel was used to detect and calculate the deposed energy and dose in any area of the water phantom using the GEANT4 platform based on the Monte Carlo method simulation. We find that, regardless of the initial proton energy, the lateral spread follows a parabolic pattern as a function of depth, and the ratio of the radius at the Bragg peak to the depth of the Bragg peak is around 2.8%. A good agreement has been found compared to other analytical models, simulation methods, and especially to experimental data.