The Software System of a Dedicated Brain PET Scanner Using Dual-Ended Readout Detectors With High-DOI Resolution

A dedicated brain PET scanner can achieve higher spatial resolution, sensitivity, and cost-effectiveness than whole-body PET scanners. In this study, we present the software system for a dedicated brain PET scanner, encompassing data acquisition, detector calibration, sinogram generation, imaging reconstruction, and data correction. The dedicated brain PET scanner features 224 depth-encoding detectors, each with a Depth of Interaction (DOI) resolution of approximately 2 mm. The electronics and data acquisition system of the scanner can be configured in different modes for detector calibration or image acquisition. Procedures for obtaining detector calibration parameters, including crystal look-up tables (LUTs), crystal depth-of-interaction LUTs, crystal energy, and timing calibration parameters, were developed. A novel virtual crystal-based sinogram generation method was developed to reduce sinogram size while preserving positioning accuracy. We also introduced a GPU-accelerated ordered subset expectation maximization imaging reconstruction method. The spatial resolution of the scanner was assessed using a point source at both the center and 1/4 axial field of view with varying radial offsets. We measured singles and prompt count rates at different activities using a monkey-sized phantom. Furthermore, we conducted scans on a 3D Hoffman brain phantom and a rabbit, demonstrated the imaging capabilities of the PET scanner.