Proton loss model for therapeutic beam dose calculations

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Physics

Background:

• Proton therapy utilizes proton beams for cancer treatment, requiring precise dose distribution prediction.
• Accurate modeling of proton transport is crucial for optimizing treatment plans and minimizing off-target radiation exposure.

Purpose of the Study:

• To develop a computationally efficient and accurate transport algorithm, the proton loss (PL) model, for predicting 3D dose distributions of therapeutic proton pencil beams.
• To incorporate key physical processes like inelastic nuclear reactions, pathlength straggling, and energy-loss straggling into the model.

Main Methods:

• Generalized the Fermi-Eyges equation to create the proton loss (PL) transport equation, incorporating inelastic nuclear reactions and pathlength straggling.
• Accounted for energy straggling by employing a weighted superposition of elementary pencil beams with varying initial energies.
• Derived the model from Fermi-Eyges diffusional multiple scattering theory and Gaussian energy straggling theory.

Main Results:

• The PL model accurately predicts the 3D dose distribution from proton pencil beams.
• Numerical comparisons with measurements and PTRAN Monte Carlo simulations validate the model's accuracy.
• The PL model demonstrates significant computational speed advantages.

Conclusions:

• The developed proton loss (PL) model offers a fast and accurate method for predicting proton beam dose distributions in radiotherapy.
• This algorithm can improve the precision and efficiency of treatment planning in proton therapy.