A high-resolution SPECT system based on a microchannel-plate imager

The authors have developed a high-resolution single-photon emission computed tomography (SPECT) system for small-animal studies with /sup 125/I. The SPECT camera uses a Hamamatsu microchannel-plate imager PIAS (photon-counting image acquisition system), a 0.7-mm-thick NaI(Tl) plate, and a lead-glass parallel-hole collimator. The 15-mm-diameter field of view (FOV) of the PIAS tube was enlarged by an optical fiber faceplate taper to provide a 26-mm camera FOV. Camera absolute sensitivity (counts detected/gamma photons emitted) is 2*10/sup -5/ for /sup 125/I. The system provides an in-plane resolution of about 0.7 mm FWHM (full width at half maximum) in the reconstructed image for a 15-mm radius of rotation. SPECT images from phantom studies and from organs in the rat and mouse provide examples of the resolving capacity of the system.<
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