Design and development of 1 mm resolution PET detectors with position-sensitive PMTs

We report our investigation of a positron emission tomography (PET) detector with 1 m spatial resolution. The prototype detector consists of a 9×9 array of 1×1×10 mm3 lutetium oxyorthosilicate (LSO) scintillator crystals coupled to Hamamatsu R5900-M64 or R5900-C12 position sensitive PMT by either optical fibers or an optical fiber bundle. With a 511 eV gamma source, the intrinsic spatial resolution of this detector was measured to be 0.92 mm. All crystals were well resolved in the flood source histogram. The measured energy and coincidence timing resolutions were around 26% and 4 ns, respectively, demonstrating that sufficient light can be extracted from these small crystals for PET applications.