A compact CT/SPECT system for small-object imaging

We report herein on a low-cost, high-performance dual imaging modality CT/SPECT system for small objects or animals. The system is realized from a commercial micro-focus X-ray tube, a Gd2O2S:Tb phosphor screen and a CCD camera. SPECT/planar imaging is obtained using a pinhole collimator with the same camera module as for X-ray/CT. Fusion of anatomic and functional images from the two modalities is easily accomplished by adjusting the magnification of the two modalities. Using an X-ray tube of 15 μm focal spot size, an image magnification of 1:1500, a field of view of 110 mm×110 mm, and adopting variable gamma detection geometry, the system may serve for numerous imaging applications and can be expanded into high-sensitivity (300 cpm/μCi), sub-millimeter (0.86 mm) SPECT resolution over a field of view of 20 mm in diameter.