Development of PET systems using SiPM based digital PET detector modules

We report the development of a compact, highly modular SiPM-based PET detector that outputs digital data via a standard serial network interface and the use of such detectors in conjunction with a software platform to obtain a scalable system architecture for PET. The detector, approximately 2.5 cm wide and 10 cm long, is made of 4 LYSO/SiPM arrays arranged in a row. Each LYSO/SiPM array is consisted of a 13x13 LYSO array optically coupled to a 6x6 array of SensL MicroFC-30035 SiPMs. For the LYSO array, the crystal size is 1.89x1.89x13 mm3 and the pitch is 2.0 mm. For the SiPM array, the pixel size and pitch are 3.2 mm and 4.2 mm, respectively. The intrinsic resolution, energy resolution and coincidence time resolution of the detector are measured to be about 1.91 mm, 15% and 1.4 ns, respectively. Crystals in a detector exhibit rather uniform performance characteristics. Two demonstration systems are developed using the developed detectors and proposed architecture, including a single-ring system (~10.4 cm diameter, 10 cm length) using 12 detectors and a two-ring system (~19 cm diameter, 20 cm length) using 48 detectors. Imaging data are successfully obtained by using these systems and the results indicate that approximately 1 mm image resolution is achieved.