Development of dual-ended readout PET detectors achieving high 3D position resolution and high timing resolution...

Time-of-flight (TOF) measurement in positron emission tomography (PET) scanner can significantly improve the signal-to-noise ratio of images. Despite the significant improvements of the timing resolution of PET detectors in recent years, further development is urgently needed.

This work aims to develop a PET detector with high 3D position resolution and excellent timing resolution by using two high timing performance ASICs for whole-body and organ-specific TOF PET scanners.

PET detector consisting of an 8 × 8 LYSO crystal array with a crystal size of 1.45 $\times$ 1.45 $\times$ 20 mm³ dual-ended read out by 4 $\times$ 4 SiPM arrays with an active pixel area of 3 $\times$ 3 mm² are measured in this work. The signals of the SiPM arrays are read out and processed separately for the timing and energy, with the energy signals multiplexed by row or column summing circuits to generate only 2 position encoding energy signals for each SiPM array and the timing signals processed by the NINO and PICO2023 ASICs to obtain a high precision timing information.

The detector achieved a flood histogram with all crystals clearly resolved, an average energy resolution of 10.7% and depth of interaction (DOI) resolution of 2.4 mm. The coincidence timing resolutions (CTR) of the detector achieved with the NINO and PICO2023 ASICs were 149 $\pm$ 3 ps and 142 $\pm$ 3 ps, respectively, if both SiPM arrays were used to measure the timing and the depth dependence of timing correction was performed. The CTRs were improved to 134 $\pm$ 4 ps and 129 $\pm$ 4 ps if only the single crystal interaction events were selected.

Both NINO and PICO2023 ASICs can be utilized to achieve a high CTR in PET detectors. The detectors developed in this work have a crystal cross-section smaller and achieve a CTR better than those of the state of the art commercial PET scanners, and can be utilized in the development of high-performance PET scanners for both whole-body and organ-specific imaging.