Extended collimator model for pencil-beam dose calculation in proton radiotherapy

Area of Science:

• Medical Physics
• Radiation Oncology

Background:

• Accurate dose calculation is crucial for effective proton radiotherapy.
• Pencil-beam dose calculations require precise modeling of beam-limiting devices like collimators.
• Existing 2D models may not fully capture the complex particle interactions within collimators.

Purpose of the Study:

• To develop and validate a simple, three-dimensional (3D) collimator model.
• To improve the accuracy of penumbra behavior in pencil-beam dose calculations for proton therapy.
• To enhance the precision of dose distributions in proton radiotherapy treatments.

Main Methods:

• Developed a novel 3D collimator model accounting for particle transmission through an extended opening.
• Incorporated phase-space distribution of particles in the collimator transmission calculation.
• Compared dose distributions from the 3D model against experimental measurements of lateral dose profiles.

Main Results:

• The 3D collimator model demonstrated superior accuracy in predicting penumbra behavior.
• Calculated dose distributions using the new model closely matched experimental lateral dose profiles.
• The 3D model significantly outperformed the conventional 2D model in accuracy.

Conclusions:

• The developed 3D collimator model provides a more accurate representation of particle transport.
• This improved modeling enhances the precision of dose calculations in proton radiotherapy.
• The findings support the clinical adoption of advanced 3D collimator models for better treatment planning.