Improved efficiency in Monte Carlo simulation for passive-scattering proton therapy.

Area of Science:

• Medical Physics
• Computational Science
• Radiation Oncology

Background:

• Monte Carlo simulations are vital for accurate dose calculations in proton therapy.
• Improving computational efficiency is essential for faster treatment planning and delivery.
• Current simulation methods can be computationally intensive, limiting real-time applications.

Purpose of the Study:

• To enhance the computational efficiency of Monte Carlo simulations for proton tracking in proton therapy treatment heads.
• To identify optimal parameters for improving simulation speed while preserving dose calculation accuracy.
• To evaluate these improvements at two distinct proton therapy facilities.

Main Methods:

• Optimized particle splitting and Russian roulette techniques were applied.
• Cylindrical symmetry of the proton beam was exploited for efficient particle distribution.
• Simulations were performed for phase space files at the treatment head exit, for water phantom, and patient geometries.

Main Results:

• Efficiency gains ranged from 19.9 to 57.3 for water phantom simulations and 78.6 for patient geometry simulations.
• Lateral-dose curves in water met clinical tolerance (2%) with low statistical uncertainty (0.5%).
• In patient geometry, 98.4% of voxels met the 2% and 2mm gamma index criteria, with systematic deviations below 0.88%.

Conclusions:

• The implemented optimization strategies significantly improve Monte Carlo simulation efficiency for proton therapy.
• The methods maintain high accuracy, ensuring reliable dose calculations for clinical applications.
• These advancements can lead to faster and more precise proton therapy treatment planning.