A compact SPECT/CT for small animal imaging

A dual-modality compact SPELT/CT system for small animal imaging has been developed. The SPELT system consisted of a pinhole collimator and plate type NaI(TI) scintillation crystal coupled to a PSPMT. The X-ray system consisted of a microfocus X-ray tube and a CMOS flat-panel detector. The SPELT system was mounted perpendicular to the X-ray system. Individual projections of SPELT and CT were acquired by rotating the animal about a vertical axis in front of the detectors. The SPELT and CT image were reconstructed using OSEM and Feldkamp's cone-beam algorithms, respectively. Mouse and rat SPELT demonstrated detailed activity distributions at the expected structures. A CT image obtained with 40 kVp and 0.5 mA presented high-resolution anatomic details. Fused SPELT/CT images demonstrated good agreement between the CT images and the corresponding uptake of the radiotracer. The SPELT/CT system developed in this study provides high-quality dual-modality images and could be useful to obtain functional images with high-resolution morphology information.