Improved sub-milimeter range-verification method for proton therapy using a composite hadron tumour marker (HTM)

Area of Science:

• Medical Physics
• Radiation Oncology
• Nuclear Instrumentation

Background:

• Proton therapy (PT) offers precise radiation delivery but is limited by range uncertainties.
• Reducing these uncertainties is crucial for optimizing treatment plans and minimizing dose to healthy tissues.
• Current range verification methods have limitations in precision and independence from beam delivery uncertainties.

Purpose of the Study:

• To investigate and validate a novel method for sub-millimetre range verification (RV) in proton therapy.
• To assess the performance of a composite hadron tumour marker (HTM) for accurate beam range determination.
• To demonstrate the potential of HTM-based RV to improve the safety and efficacy of proton therapy.

Main Methods:

• Development and testing of a composite hadron tumour marker (HTM) using three candidate materials.
• Utilizing high-purity germanium detectors for precise measurement of gamma-ray signals emitted from activated HTM.
• Employing a PMMA phantom to simulate and account for background gamma-ray signals from tissue activation.

Main Results:

• The composite HTM effectively utilized the strongest nuclear reactions for signal generation.
• Improved detector resolution and phantom simulation led to more accurate gamma-ray measurements.
• Range verification using HTM achieved an average deviation of 0.13(22)mm from the expected proton beam range.

Conclusions:

• The developed HTM-based RV method provides highly accurate, sub-millimetre range verification in proton therapy.
• This technique is independent of beam delivery uncertainties, offering a robust solution for range determination.
• Clinical implementation of HTM RV could enable smaller safety margins, expanding the therapeutic potential of proton therapy.