Performance evaluation of the fully engineered YAP-(S)PET scanner for small animal imaging

At the Department of Physics of the University of Pisa, a new and fully engineered version of the YAP-(S)PET small animal scanner has been recently installed. The new YAP-(S)PET is able to perform both PET and SPECT studies on small animals. The scanner is made up of four heads: each one is composed of a 4times4 cm² YAlO₃:Ce (or YAP:Ce) matrix of 20times20 elements, 2times2times25 mm³ each, coupled to a PS-PMT (Hamamatsu R2486). The four modules are positioned on a rotating gantry. The switching to the SPECT modality is easily made by mounting a high resolution parallel hole (0.6 mm Phi, 0.15 mm septum) lead collimator in front of each crystal. This paper reports the performance of the system in terms] of absolute sensitivity and spatial resolution for both PET and SPECT modalities. The scatter fraction and noise-equivalent count rate (NEC) for a mouse phantom for different energy windows have been measured. Images of phantoms and animals are also presented