Monte Carlo method to study the proton fluence for treatment planning

Area of Science:

• Medical Physics
• Radiation Oncology
• Particle Therapy

Background:

• Proton therapy is emerging for eye melanoma treatment at the Hahn Meitner Institute (HMI).
• Accurate characterization of proton beams is crucial for effective radiation delivery.
• Existing methods like beam penumbra offer indirect information about beam properties.

Purpose of the Study:

• To investigate the primary fluence distribution of proton beams used in therapy.
• To introduce an alternative parameterization of proton beams for improved treatment planning.
• To assess the impact of beamline components on therapeutic proton beams.

Main Methods:

• Utilized Monte Carlo simulations to model proton beam interactions.
• Analyzed the influence of scattering foils, range shifters, modulator wheels, and collimators.
• Developed a new parameterization based on the phase space distribution (energy, position, angle).

Main Results:

• Quantified the modification of proton beams by various beamline components.
• Introduced a novel parameterization of the proton beam exiting the accelerator and before the patient.
• Demonstrated that phase space distribution parameters offer a more comprehensive beam characterization.

Conclusions:

• The proposed parameterization provides a more direct and informative input for pencil-beam treatment planning algorithms.
• This method allows for the investigation of beam delivery system modifications' effects on therapeutic beams.
• Enhanced characterization of proton beams will improve the precision and efficacy of eye melanoma proton therapy.