Monitoring the Bragg peak location of 73 MeV/u carbon ions by means of prompt $\gamma$-ray measurements

TL;DR

This study demonstrates a time-of-flight method to measure prompt gamma rays emitted by 73 MeV/u carbon ions in order to monitor the Bragg peak location during ion therapy, enabling real-time 3D dose verification.

Contribution

It introduces a novel prompt gamma measurement technique that correlates gamma emission with ion path for real-time dose monitoring in ion therapy.

Findings

Successful correlation between prompt gamma emission and ion path.

Potential for real-time 3D control of irradiation.

Minimized shielding improves measurement accuracy.

Abstract

By means of a time-of-flight technique, we measured the longitudinal profile of prompt $\gamma$-rays emitted by 73 MeV/u $^{13}$C ions irradiating a PMMA target. This technique allowed us to minimize the shielding against neutrons and scattered $\gamma$-rays, and to correlate prompt gamma emission to the ion path. This correlation, together with a high counting rate, paves the way toward real-time monitoring of the longitudinal dose profile during ion therapy treatments. Moreover, the time correlation between the prompt gamma detection and the transverse position of the incident ions measured by a beam monitor can provide real-time 3D control of the irradiation.