Studies for performance improvement of a small animal PET prototype based on continuous LYSO crystals and SiPM matrices

A prototype of a high resolution small animal PET scanner with continuous LYSO crystals coupled to SiPM matrices has been developed. Initial tomographic images of point-like sources have been obtained with a spatial resolution of 0.7±0.2 mm FWHM using crystals with 5 mm and 10 mm thickness. The next step in the prototype development is to improve the scanner performance. From the instrumentation point of view, a slight misalignment of the detector heads has been identified as well as a malfunctioning in the ADC that leads to a degraded time resolution. In addition, a GEANT4 simulation of one detector head has been implemented including generation and transportation of optical photons for a better understanding of its response and to predict its performance in different conditions. Squared and tapered crystals geometries have been simulated. Simulated data have been compared to experimental data, showing good agreement.