Investigation of a compact DOI-PET system for small animal imaging

In this work, we experimentally investigate the resolution performance characteristics of a compact small-animal DOI-PET system. Conceptual design of this system employs sixteen 8×8 LSO/LYSO dual-layer DOI block detectors, with individual 2.1×2.1×10 mm³ crystals. These detectors are arranged to form a 5 cm-radius detector ring to yield an intended 4.8 cm-radius field-of-view (FOV). As expected, our measurements reveal significant resolution degradation outside the center of the FOV due to a significant level of parallax errors arising from the proposed compact geometry. This resolution degradation, however, can be substantially reduced by use of an analytical sinogram restoration technique to yield uniform spatial resolution inside the FOV. This technique is computationally efficient; it can be incorporated as an integral part of a PET imager to achieve high-performance in a cost-effective manner.