A methodology for optimizing treatment head angle arrangement for multi-angle FLASH intensity modulated radiation...

Area of Science:

• Radiation Oncology
• Medical Physics
• Computational Biology

Background:

• Flash radiotherapy technology enables rapid, high-dose radiation delivery.
• Current FLASH radiotherapy platforms utilize multiple treatment heads, but optimal angular configurations are undetermined.
• Determining optimal treatment head angles is crucial for maximizing clinical efficacy and feasibility.

Purpose of the Study:

• To develop and evaluate a methodology for optimizing treatment head angles in multi-angle FLASH radiotherapy.
• To minimize angular discrepancies between virtual FLASH radiotherapy plans and clinically used intensity-modulated radiation therapy (IMRT) plans.
• To assess the impact of imaging system constraints on optimal treatment head configurations.

Main Methods:

• Adaptive Simulated Annealing (ASA) was employed to optimize treatment head angles, treating each angle as an independent variable.
• The objective function was defined as the total angular discrepancy between beam directions.
• A dataset of 69,928 beams from 8,866 IMRT plans for various cancers was used for evaluation.

Main Results:

• Optimized five-treatment-head configurations significantly reduced angular discrepancies compared to equally spaced angles (37.8°-38.9° vs. 78.4°).
• The optimized configuration with an imaging system constraint resulted in an average discrepancy of 38.9°.
• The optimized configuration without an imaging system constraint yielded an average discrepancy of 37.8°.

Conclusions:

• A novel methodology for optimizing treatment head angles in multi-angle FLASH radiotherapy has been proposed.
• The optimized configurations offer a practical and effective solution for clinical FLASH radiotherapy applications.
• This approach balances treatment performance with the feasibility of implementation in clinical settings.