Characterization of LYSO and CeBr3 Detectors with Lateral Sides Readout for a Multilayer Compton-PET

Two of the limitation factors of current PET scanners are their low sensitivity and lack of high image contrast. In order to improve these parameters, Compton interactions, which are usually discarded or unavoidably averaged, must be distinguished and included in the image reconstruction process. To achieve this, one of our proposals is a multi-layer detector approach employing thin scintillation layers with photodetectors coupled to all four lateral sides of the crystal. In the work presented here, a characterization of detectors based on LYSO and CeBr
3
crystals with lateral sides readout has been performed. Both crystals have an active volume of 51×51×3 mm
³
, resulting in a very high aspect ratio of 17. The CeBr
3
crystal also includes a 5 mm thick quartz glass frame due to encapsulation constraints. The obtained results show an energy resolution of 12.1% and 9.1% FWHM for the LYSO and CeBr
3
detectors, respectively. Pilot spatial resolutions ranging from 2.7 mm up to 4.3 mm for the LYSO crystal and from 4.1 mm up to 11.2 mm for the CeBr
3
crystal were observed. These results suggest that the quartz glass frame surrounding the CeBr
3
crystal significantly affects the light distribution of the optical photons reaching the photodetectors, worsening the performance of this kind of encapsulated detector.