Analysis of 70 - 300 MeV Proton Energy on Homogeneous and Inhomogeneous Phantoms using PHITS Monte Carlo Package

Proton therapy is a radiotherapy technique using proton particles for reach the target in a straight line and minimize damage to the surrounding tissue. Proton particles that penetrate the body will be deposited at a certain depth and produce a Bragg peak. This study aims to determine the percentage depth dose (PDD) produced by proton radiation in homogeneous and inhomogeneous phantoms. Homogeneous phantom contains water, bone, or lungs material, while inhomogeneous phantom consists of several materials, namely water, bone, and lungs. The interaction of phantom and proton radiation was simulated using the Monte Carlo-based PHITS software. The result indicate that the material density and the proton energy were influencing the dept of Bragg peak. For energy 70 MeV, the Bragg peak position for the water phantom, bone phantom, and lung phantom were 3.80 cm, 2.60 cm, and 15.8 cm. The increase of proton energy causes a deeper Bragg peak position.