SU-E-T-488: Dose Calculation Model Using the Simplified Monte Carlo Method with an Initial Beam Model Adapted to a...

Area of Science:

• Medical Physics
• Radiation Oncology
• Computational Science

Background:

• Proton therapy requires accurate dose calculation for effective cancer treatment.
• Beam-wobbling delivery systems introduce complexities in dose distribution.
• Existing models may not fully capture the nuances of wobbled beam dose patterns.

Purpose of the Study:

• To develop and validate an accurate dose calculation model for a beam-wobbling delivery system.
• To adapt a simplified Monte Carlo (SMC) method for precise dose calculation in proton therapy.
• To reproduce differing dose distributions in lateral x- and y-directions specific to the wobbler system.

Main Methods:

• Developed a simplified Monte Carlo (SMC) model tracking individual protons.
• Generated an initial phase space adapted to the beam-wobbling system using an analytical method.
• Validated the model by measuring dose distributions in a homogeneous phantom with a 2D array of ionization chambers.

Main Results:

• The SMC model accurately reproduced measured dose distributions, showing differences between x- and y-directions.
• The model successfully predicted dose increments in edge regions due to collimator scatter.
• The simplified Monte Carlo method demonstrated its advantage in calculating complex dose patterns.

Conclusions:

• A novel dose calculation model based on the simplified Monte Carlo method was successfully developed for beam-wobbling systems.
• Adapting the initial beam model to the wobbling system enabled accurate reproduction of lateral dose distribution differences.
• The validated SMC method enhances the precision of dose calculation in advanced proton therapy delivery.