Performance of a depth encoding PET detector module using light sharing and single-ended readout with SiPMs.

Detectors with depth encoding capability, good energy resolution and good timing resolution are required to develop high performance whole body and total body PET scanners. In this work, an 8  ×  8 LYSO array with crystal size of 3  ×  3  ×  20 mm was fabricated by using coupling materials that included 5 mm optical glue, 9 mm triangle ESR reflector and 6 mm rectangle ESR reflector from the top to the bottom in between adjacent crystals in one direction. The LYSO array was single-ended read out by an 8  ×  8 SiPM array with one-to-one coupling. Row and column summing circuit was used to read out the SiPM signals. The depth of interaction (DOI) of the detector was measured with the depth dependent light sharing between adjacent crystals while maintaining acceptable energy resolution and timing resolution. The performance of the detector module was evaluated. All crystals can be clearly resolved from the measured flood histogram. An average DOI resolution of 4.62 mm and an average timing resolution of 518 ps are obtained for events with E  >  400 keV. The average energy resolution of the detector is 13.5%. This work provides a cost-effective depth encoding detector module that can be used to build high performance whole body and total body PET scanners in the future.