Development of Whole-Body TOF-DOI PET Detector Using Dual-Ended Readout Method

Positron emission tomography (PET) is the most sensitive <i>in vivo</i> molecular instrumentation. The image quality of PET can be significantly enhanced by incorporating time-of-flight (TOF) and depth-of-interaction (DOI) information. In this study, whole-body TOF-DOI PET detectors based on the dual-ended readout method were developed to simultaneously provide good TOF and DOI information. Each detector consisted of two 8 × 8 Hamamatsu S14161-3050-08 silicon photomultiplier (SiPM) arrays coupled to both ends of an 8 × 8 lutetium-yttrium oxyorthosilicate (LYSO) array with a thickness of 20 mm. Both the LYSO and SiPM arrays had a pitch of 3.2 mm, allowing each LYSO element to be coupled to two SiPM elements, one at each end of the crystal, to achieve the optimal timing resolution. Experimental results demonstrated that the detectors achieved a coincidence timing resolution of 234 ± 7 ps, an energy resolution of 13.7 ± 2.0%, and a DOI resolution of 2.6 ± 0.2 mm. These results suggest that the developed detectors are suitable for constructing whole-body TOF-DOI PET scanners with uniform spatial resolution across the entire field-of-view.