Proton therapy offers highly conformal dose delivery through the Bragg peak phenomenon, making it a powerful tool for treating deep-seated tumors while minimizing damage to surrounding healthy tissues. Accurate dose modeling and biological optimization in this context demand robust simulation tools. This thesis investigates advanced Monte Carlo (MC) scoring strategies for proton therapy treatment planning by comparing two state-of-the-art platforms: GATE, a Geant4-based CPU simulation toolkit known for its high-fidelity physics modeling, and FRED, a GPU-accelerated engine optimized for clinical speed and efficiency. After detailing the physical principles underpinning proton therapy, the thesis introduces the simulation setup replicating PSI’s Gantry 2 beamline.