New algorithm to estimate proton beam range for multi-slit prompt-gamma camera

Abstract

The prompt gamma imaging (PGI) technique is considered as one of the most promising approaches to estimate the range of proton beam in the patient and unlock the full potential of proton therapy. In the PGI technique, a dedicated algorithm is required to estimate the range of the proton beam from the prompt gamma (PG) distribution acquired by a PGI system. In the present study, a new range estimation algorithm was developed for a multi-slit prompt-gamma camera, one of PGI systems, to estimate the range of proton beam with high accuracy. The performance of the developed algorithm was evaluated by Monte Carlo simulations for various beam/phantom combinations. Our results generally show that the developed algorithm is very robust, showing very high accuracy and precision for all the cases considered in the present study. The range estimation accuracy of the developed algorithm was 0.5–1.7 mm, which is approximately 1% of beam range, for 1 × 109 protons. Even for the typical number of protons for a spot (1 × 108), the range estimation accuracy of the developed algorithm was 2.1–4.6 mm and smaller than the range uncertainties and typical safety margin, while that of the existing algorithm was 2.5–9.6 mm.