Performance measurements of a SSPM-LYSO-SSPM detector module for small animal positron emission tomography

We present the performance of a compact PET detector module with a depth-of-interaction (DOI) capability based on a LYSO scintillator array coupled at both ends to CMOS solid state photomultipliers (SSPM). In this paper we present flood imaging, energy resolution, coincidence timing and DOI resolution results for a prototype PET detector module consisting of a 4 × 4 block of LYSO scintillators, each crystal 3 measuring 1.43 × 1.43 × 20 mm³ coupled to 4 × 4 array of SSPMs, 2 each SSPM element is 1.5 × 1.5 mm². All 16 elements in the flood 22 image recorded with ²²Na gamma-ray source at all depths were clearly visible and well separated from each other. The measured FWHM energy resolution with 511 keV gamma rays for all crystals in the array ranged between 13% - 17% (FWHM). The timing resolution measured for the complete detector module in coincidence with LYSO-PMT detector was 2.3 ns (FWHM) and for the individual crystals ranged between 1.1 ns - 1.3 ns (FWHM). The DOI resolution measured for all crystals in the array was ranged between 2.3 mm - 2.9 mm.