Treatment verification by Prompt Gamma-Ray Timing on an anthropomorphic head phantom under pre-clinical conditions

Range verification is essential to develop the full potential of proton therapy. The prompt gamma-ray timing method [1]-[2] is a promising candidate for its clinical realization, since it is a light-weight system with small footprint, which can be easily integrated into existing treatment facilities.To verify the clinical applicability of this system, range deviations were introduced on a realistic head phantom using plastic plates of up to 7 mm thickness. The produced prompt gamma radiation was detected simultaneously by eight CeBr\textsubscript{3} detectors. Several improvements to the detector hardware and setup made it possible to reliably detect the introduced range deviations.Thus, this study demonstrates for the first time that the prompt gamma-ray timing system can resolve range deviations of a few millimeters at clinically realistic pencil beam spot intensities, making it a strong option for on-line treatment verification.