Proton energy optimization and reduction for intensity-modulated proton therapy.

Area of Science:

• Medical Physics
• Radiation Oncology

Background:

• Intensity-modulated proton therapy (IMPT) uses spot-scanning delivery.
• Proton energy variation is crucial for depth penetration.
• Energy switching significantly impacts total treatment time.

Purpose of the Study:

• To investigate the feasibility of optimizing and reducing proton energies in IMPT planning.
• To develop a method for selecting a subset of energies while maintaining dosimetric quality.

Main Methods:

• Proposed an iterative mixed-integer programming optimization method.
• Applied the method to six patient datasets (prostate, lung, mesothelioma).
• Evaluated dosimetric criteria and energy reduction percentages.

Main Results:

• Successfully reduced the number of proton energies in all tested IMPT plans.
• Energy reductions ranged from 11.0% to 26.5% across different cancer types.
• Dosimetric performance was maintained despite energy reduction.

Conclusions:

• Proton energy optimization is feasible in IMPT planning.
• Reduced energy usage can enhance IMPT delivery efficiency and patient throughput.
• This approach is particularly beneficial for proton centers with slow energy switching systems.