Preliminary evaluation of the microPET P4: a PET system dedicated to small animal imaging

Summary form only received as follows: The microPET Primate 4 ring system (P4) is a small animal PET tomograph with an 8 cm axial extent, an 18 cm transaxial field of view (FOV) and an animal port of 22 cm diameter. The system is comprised of 168 detectors, each with an 8×8 array of 2.2×2.2×10 mm LSO crystals, for 32 crystal rings with a detector diameter of 26 cm. The crystals of each detector are coupled to a Hamamatsu H5900-C8 position sensitive photomultiplier tube (PMT) via a 10 cm long fiber bundle. The reconstructed image resolution was measured with an F-18 line source positioned at different radial offsets [0-5 cm] across the FOV. The reconstructed radial and tangential components of the spatial resolution range from 2.3 mm at the center to 3.0 mm at 5 cm radial offset. The tomograph has peak system sensitivity of 1.7% at the center FOV with an energy window of 250-700 keV. The energy resolution of the individual crystal elements ranges from 22 to 34%, with a mean of 26%. A miniature Derenzo and a monkey brain phantom were scanned and reconstructed with filtered backprojection to illustrate the capabilities of the tomograph. Randoms subtraction was performed on all acquisitions