Experimental validation of daily adaptive proton therapy

Area of Science:

• Medical Physics
• Radiation Oncology
• Radiotherapy Technology

Background:

• Anatomical variations during proton therapy necessitate prompt treatment plan adjustments to maintain dose accuracy.
• Existing workflows can be time-consuming, posing challenges for adaptive radiotherapy.

Purpose of the Study:

• To develop and evaluate an efficient online adaptive proton therapy workflow for skull-base/cranium treatments.
• To assess the dosimetric and timing performance of the daily adaptive proton therapy (DAPT) workflow.

Main Methods:

• Developed an in-house DAPT software and anthropomorphic phantom for experimental validation.
• Implemented a workflow involving daily CT imaging, rigid propagation of template structures, and full re-optimization of the daily plan.
• Utilized clinically integrated software for efficient online adaptation and automated quality assurance (QA) checks.

Main Results:

• Film measurements demonstrated high agreement between calculated and delivered doses for multi-fraction DAPT treatments.
• Gamma pass rates of >92% (3%/3 mm) were achieved when comparing measured dose to the template plan.
• Gamma pass rates of >99% were obtained when comparing measurements to Monte Carlo doses of daily plans.

Conclusions:

• The developed DAPT workflow is accurate and efficient for skull-base treatments.
• The workflow can be implemented within a timeframe comparable to standard proton therapy delivery.
• This approach mitigates the dosimetric impact of anatomical changes during treatment.