A compact SPECT/CT system for small animal imaging

A dual-modality compact SPECT/CT system for small animal imaging was developed. The SPECT system consisted of a pinhole collimator and continuous NaI(Tl) scintillation crystal coupled to a PSPMT. The CT system consisted of a microfocus X-ray tube and a CMOS flat-panel detector. The SPECT system was mounted perpendicular to the X-ray system. Individual projections of the SPECT and the CT were acquired by rotating the animal on a vertical axis in front of the detectors. The SPECT and CT images were reconstructed using OSEM and Feldkamp's cone-beam algorithms, respectively. Mouse and rat SPECT images demonstrated detailed activity distribution at the expected structures. A CT image obtained with 40 kVp and 0.5 mA presented high-resolution anatomic details. Fused SPECT/CT images demonstrated good agreement between the CT images and the corresponding uptake of the radiotracer. The SPECT/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.