Initial System Performance Evaluation of a Second-Generation RF-Penetrable Brain TOF-PET Insert for Simultaneous PET/MRI

Simultaneous positron emission tomography / magnetic resonance imaging (PET/MRI) has unique advantages in providing complementary, concurrent information about anatomic, functional, and molecular changes in diseases. We are developing an MR-compatible RF-penetrable brain time-of-flight (TOF)-PET insert with a smaller scintillation crystal size and smaller PET ring diameter compared to clinical whole-body PET scanners, which leads to higher spatial resolution and sensitivity. We reported PET performance and MR-compatibility of our MR-compatible detector modules before. This paper reports the initial PET system performance of our second-generation RF-penetrable PET insert with half of the system (8 out of 16 detector modules) assembled. The excellent global photopeak energy resolution and global CTR, 230.5 ± 0.2ps FWHM and 11.29 ± 0.01% FWHM, are preserved as we scale up the system. The coincidence count rate is 92.7 ± 0.1 kcps and the average temperature of all ASIC chips on 8 detector modules is 24.4 ± 0.2 oC over a one-hour point source experiment. The system performance during the one hour experiment is stable. For the resolution phantom study, we can resolve all 3.2mm rods and part of 2.8mm rods without applying normalization, TOF, scatter, attenuation, and random corrections. The image quality will be significantly improved after we assemble the remaining detector modules and implement all image corrections. We will report a resolution phantom study with the full 16 detector modules assembled and all image corrections implemented and MR compatibility evaluation at the conference.