GEANT4 simulation of a range verification method using delayed γ spectroscopy of a ⁹²Mo marker

Area of Science:

• Medical Physics
• Nuclear Medicine
• Radiation Oncology

Background:

• Accurate proton therapy range verification is crucial for effective cancer treatment.
• Current in-vivo verification methods have limitations in precision and signal-to-noise ratio.

Purpose of the Study:

• To propose and evaluate a novel in-vivo proton therapy range verification technique.
• To assess the feasibility of using a molybdenum hadron tumour marker for real-time range monitoring.

Main Methods:

• Simulated proton therapy treatment scenarios using the GEANT4 Monte Carlo package and ROOT.
• Investigated fusion-evaporation reactions between proton beams and molybdenum nuclei.
• Analyzed delayed characteristic gamma-ray emissions for signal detection off-beam.

Main Results:

• The proposed molybdenum marker technique enables direct measurement of proton beam energy.
• Delayed gamma-ray intensity correlates precisely with proton beam range relative to the marker.
• Simulations indicate sub-millimetre uncertainty in range verification.

Conclusions:

• The molybdenum hadron tumour marker technique is a viable method for in-vivo proton therapy range verification.
• This approach offers improved signal-to-noise ratio through off-beam gamma-ray detection.
• The technique holds promise for enhancing the safety and precision of proton therapy treatments.