Performance evaluation of a compact PET/SPECT/CT tri-modality system for small animal imaging applications

PET, SPEcT and CT imaging techniques are widely used in preclinical small animal imaging applications. In this paper, we present a compact small animal PET/SPECT/CT tri-modality system. A dual-functional, shared detector design is implemented which enables PET and SPECT imaging with a same LYSO ring detector. A multi-pinhole collimator is mounted on the system and inserted into the detector ring in SPECT imaging mode. A cone beam CT consisting of a micro focus X-ray tube and a CMOS detector is implemented. The detailed design and the performance evaluations are reported in this paper. In PET imaging mode, the measured NEMA based spatial resolution is 2.12 mm (FWHM), and the sensitivity at the central field of view (CFOV)is 3.2%. The FOV size is 50 mm (circle divide) x 100 mm (L). The SPECT has a spatial resolution of 1.32 mm (FWHM) and an average sensitivity of 0.031% at the center axial, and a 30 mm (circle divide) x 90 mm (L) FOV. The CT spatial resolution is 8.32 lp/rnm @10%WTF, and the contrast discrimination function value is 2.06% with 1.5 mm size cubic box object. In conclusion, a compact, Lri-modaliLy PET/SPECT/CT system was successfully built with low cost and high performance. (C) 2015 Elsevier B.V. All rights reserved.