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

Abstract

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\u2009\u2009×\u2009\u20098 LYSO array with crystal size of 3\u2009\u2009×\u2009\u20093\u2009\u2009×\u2009\u200920\u2009mm3 was fabricated by using coupling materials that included 5\u2009mm optical glue, 9\u2009mm triangle ESR reflector and 6\u2009mm 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\u2009\u2009×\u2009\u20098 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\u2009mm and an average timing resolution of 518\u2009ps are obtained for events with E\u2009\u2009>\u2009\u2009400\u2009keV. 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.