Double-end readout of Lu-based scintillation pixels in Positron Emission Tomography

Depth of interaction (DOI) information allows to increase the field of view (FOV) of Positron Emission Tomograph (PET) without degrading the spatial resolution in the peripheral parts of FOV. Light division between two ends of scintillation pixel using two photodetectors and appropriate algorithm for signal processing as a method of DOI information extraction is studied in the present work with 2×2×20 mm3 LSO, 2×2×20 mm3 and 4×4×25 mm3 LuYAP pixels under annihilation gamma-quanta excitation and two PMT readout. Influence of optical absorption in scintillation crystal and surface quality on spatial resolution is studied. Spatial resolution about 3 mm were achieved for optimal crystal surface finishing. Such a result allows to apply the proposed method to determine not only DOI but also the main coordinates in tomography: axial or radial. Relatively simple mathematics for real-time signal processing is proposed for coordinate of interaction determination.