Monitoring the Bragg peak location of 73MeV∕u carbon ions by means of prompt γ-ray measurements

Abstract

By means of a time-of-flight technique, we measured the longitudinal profile of prompt $\gamma$ -rays emitted by $73\mathrm{MeV}∕\mathrm{u}$ ${}^{13}\mathrm{C}$ ions irradiating a polymethyl methacrylate 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 three dimensional control of the irradiation.