Abstract
The combined effort of several laboratories at our institution resulted in the building of the first high resolution PET/CT prototype dedicated to imaging the body extremities. Ongoing clinical trials for breast cancer diagnosis and assessment of response to treatment underlined the need for a second generation prototype with improved electronics and spatial resolution. A preliminary version has been assembled and fully characterized. In this work we present further improvements in the detector performance as well as the readout electronics for the PET component. The detector consists of a 16×16 array of 1.27×1.27×20mm(3) LYSO crystals, the smallest crystal size for completed breast PET prototypes to date, directly coupled to a position-sensitive photomultiplier tube (PSPMT). The scintillator crystals are polished on all 6 faces and separated by ~70 μm ESR reflector. The readout electronics were redesigned to reduce their footprint and improve timing resolution. We report a detector energy and timing resolution of 12% and 1.0 ns, respectively, and an average intrinsic spatial resolution of 1.29 mm (central row in one detector array). The new PET/CT has been fully assembled and initial system characterization is being perfomed. We report a system energy resolution of 15.7%, a timing resolution of 1.5 ns and an FBP image spatial resolution in the center of the FOV of 1.6 mm.