Development Of A Preclinical Pet System Based On Pixelated Lyso Crystals And Sipm Arrays

PET imaging is playing an important role in the field of molecular imaging regarding its high sensitivity in detection of radiotracers. Hence, development of dedicated preclinical PET scanners with better performance parameters utilizing state-of-the-art technology has an ongoing trend. We recently developed a prototype preclinical PET scanner based on pixelated lutetium - yttrium oxyorthosilicate (LYSO) crystals and Silicon Photomultiplier (SiPM) arrays. In this paper, we report on the system design properties together with calibration/correction algorithms, image reconstruction, and preliminary evaluation of performance parameters and animal imaging. The detection subsystem consists of 10 blocks forming a full-ring bore. Each block is composed of attachment of a 24 x 24 LYSO crystal array to a 12x12 SiPM array. After pre-processing and time-stamping in each block, a mainboard is responsible for acquiring the data from all the blocks, coincidence detection, position extraction, and transferring them to a computer where other processing steps are performed. The initial assessments showed that the spatial resolution of the system at the center of field-of-view is about 1.8 mm while the sensitivity is around 1.4%. Also, reconstructed images of a rat scan after administration of 7.4 MBq 18F-sodium fluoride (NaF) revealed acceptable performance of the scanner in imaging of animal models. Time resolution and average energy resolution of the system after corresponding corrections were measured as 1.85 ns and 12.5%, respectively.