Depth-of-interaction enhanced Compton camera using pixelated LYSO(Ce) scintillator arrays and dual-ended SiPMs

This study aims to enhance the position resolution of a scintillator-based Compton camera and improve spatial resolution in image reconstruction using depth-of-interaction (DOI) correction technology. A dual-end readout method was used to acquire depth information from the scintillator array. The prototype DOI-based Compton camera was developed using a Cerium-doped Lutetium-Yttrium Oxyorthosilicate (LYSO(Ce) scintillator array, and a calibration process was conducted to correlate depth positions with light intensity signals. A Synder model in Geant4 was utilized to simulate the detection of 0.478 MeV gamma photons in Boron Neutron Capture Therapy (BNCT). The impact of DOI information on spatial resolution and image accuracy was evaluated using the Simple Back Projection (SBP) and Maximum Likelihood Expectation Maximization (MLEM) algorithms. The dual-end readout method yielded a linear correlation between the depth positions and the ratio of dual-end signals. The average DOI resolution was found to be 2.494 mm. For 0.478 MeV photon images in BNCT environments, incorporating DOI information improved spatial resolution by 6.7 mm using the SBP algorithm compared to images without DOI information. Using the MLEM algorithm, the spatial resolution improved by 3.1 mm for the same photon energy. Incorporating DOI calibration information into the LYSO dual-layer scintillator Compton camera significantly improves the quality of 0.478 MeV prompt gamma photon image reconstruction in BNCT (Boron Neutron Capture Therapy) environments. This advancement enables more accurate measurements for real-time boron concentration and distribution monitoring, contributing to the continued development of BNCT.