First experimental test of a coded-mask gamma camera for proton therapy monitoring

TL;DR

This study demonstrates the feasibility of a coded-mask gamma camera for real-time proton therapy monitoring, showing promising accuracy and rate capability in clinical-like conditions, potentially improving treatment safety.

Contribution

First experimental validation of a coded-mask gamma camera for proton therapy range verification in clinical conditions.

Findings

Achieved 1.7 mm precision in distal falloff detection with 10^8 protons

Performance aligned with Monte Carlo simulations despite hardware limitations

System demonstrated sufficient rate capability for clinical proton beam intensities

Abstract

Objective. The objective of the presented study was to evaluate the feasibility of a coded-mask (CM) gamma camera for real-time range verification in proton therapy, addressing the need for a precise and efficient method of treatment monitoring. Approach. A CM gamma camera prototype was tested in clinical conditions. The setup incorporated a scintillator-based detection system and a structured tungsten collimator. The experiment consisted of the irradiation of PMMA phantom with proton beams of energies ranging from 70.51 to 108.15 MeV. Experimental data were benchmarked against Monte Carlo simulations. The distal falloff position was determined for both experimental data and simulations. Main results. The tested CM camera achieved a statistical precision of distal falloff position determination of 1.7 mm for $10^8$ protons, which is consistent with simulation predictions, despite hardware limitations such as non-functional detector pixels. Simulations indicated that a fully operational setup would further improve the performance of the detector. The system demonstrated rate capability sufficient for clinical proton beam intensities and maintained performance without significant dead time. Significance. This study validates the potential of the CM gamma camera for real-time proton therapy monitoring. The technology promises to enhance treatment accuracy and patient safety, offering a competitive alternative to existing approaches such as single-slit and multi-slit systems.