An uncertainty-incorporated method for fast beam angle selection in intensity-modulated proton therapy

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Planning

Background:

• Intensity Modulated Proton Therapy (IMPT) requires precise beam angle selection for optimal treatment.
• Current methods may not fully balance plan optimality and robustness against uncertainties.

Purpose of the Study:

• To introduce and validate a novel metric, the ψ-score, for ranking IMPT beams.
• To assess the effectiveness of ψ-score guided beam angle selection in diverse clinical scenarios.

Main Methods:

• The ψ-score was developed to rank beam optimality and robustness for IMPT.
• Four plan types were generated for Lung, Pancreas, Prostate+Node, and Prostate cases: Conventional Angle (CA) and Suitable Angle (SA) plans, with and without Robust Optimization (RO).
• Beam angles in SA and SA-RO plans were determined using the ψ-score.

Main Results:

• ψ-score guided beam angle selection significantly improved plan quality (dose distribution, DVH) compared to conventional methods.
• Plan robustness was maintained without substantial compromise.
• Beam angle optimization using ψ-score with RO took 20-30 minutes, while without RO it took 10-15 minutes.

Conclusions:

• The proposed ψ-score is effective in determining optimal beam angles for IMPT.
• This method enhances treatment plan quality across various anatomical sites.
• The ψ-score provides a valuable tool for improving IMPT planning.