ABSTRACT
Objective:A two-dimensional (2D) in-house-built scintillator detection system (SDS) was utilized for quality assurance of the active spot scanning proton and heavy ion accelerator, aiming to establish a rapid detection method and provide reference for the quality of proton and heavy ion beam (spot position, spot size, virtual source-to-axis distance, profile depth dose distribution and beam range).Methods:The SDS consisted of a ceramic gadolinium-sulfoxylate phosphor-scintillating screen, a mirror and a commercial digital camera. The dose distribution image was obtained based on scintillator, mirror reflector and optical signal acquisition device to transform the proton and heavy ion beam into visible light through sulfur gadolinium oxide scintillator and collect visible light information to meet the clinical requirements for the quality of proton and heavy ion beam.Results:The deviation of spot position measured by multifilament proportional chamber and the SDS was less than 1mm. The differences of beam spot size measured by multifilament proportional chamber and the SDS were (1.40±0.59)mm for protons, and (0.5±0.08)mm for carbon ions. For 429.25MeV/u carbon, the virtual source-to-axis distance (V SAD) at the x-and y-axes was 751.8cm and 805.6cm. And difference between physical distance and virtual source-to-axis distance was less than 1%. The range of 287.5MeV/u carbon measured by SDS was 160mm. Conclusions:The in-house-built scintillator detector can measure beam spot position and size, virtual source, depth distribution curve and range, which can be used as an effective tool for quality assurance control of proton and heavy ion therapy.