A compact detector, sized particularly for imaging a mouse, is described. The active area of the detector is approximately 46 mm x 96 mm. Two flat-panel Hamamatsu H8500 position-sensitive photomultiplier tubes (PSPMTs) are coupled to a pixellated NaI(TI) scintillator which views the animal through a copper-beryllium (CuBe) parallel-hole collimator specially designed for I-125. Although the PSPMTs have insensitive areas at their edges and there is a physical gap, corrections for scintillation light collection at the junction between the two tubes results in a uniform response across the entire rectangular area of the detector. The system described has been developed to optimize both sensitivity and resolution for in-vivo imaging of small animals injected with iodinated compounds. We demonstrate an in-vivo application of this detector, particularly to SPECT, by imaging mice injected with approximately 10-15 mu Ci of I-125.

A compact detector, sized particularly for imaging a mouse, is described. The active area of the detector is approximately 48 mmtimes96 mm. Two flat-panel Hamamatsu H8500 position sensitive photomultiplier tubes (PSPMT) are coupled to a pixellated NaI(Tl) scintillator which views the animal through a copper-beryllium (CuBe) parallel-hole collimator. Because the PSPMTs have insensitive areas at their edges, particular care has been given to bridging the gap where the two tubes join so as to maintain uniform response across the entire rectangular area of the detector. The system described has been developed to optimize both sensitivity and resolution for in vivo imaging of small animals injected with iodinated compounds. We demonstrate an in vivo application of this detector by imaging a mouse injected with 10 muCi of 125I

A rotating cylindrical gantry apparatus holding a pair of Hamamatsu R3292 position sensitive photomultiplier tubes (PSPMTs), each of which can include either a parallel-hole collimator or a pinhole collimator, has been used to gather planar images and single photon emission computer tomography (SPECT) data of an entire mouse. In addition, in a number of experiments a magnified view of a specific organ was obtained with pinhole collimation. The scintillators used were pixelated NaI(Tl) or CsI(Tl) with pixels 1/spl times/1/spl times/3 mm and were air coupled to the PSPMTs. The active area of each detector was a circle about 110 mm in diameter. The parallel hole detector had an intrinsic resolution in planar images of 2 mm and the pinhole collimator was used in a magnification which yielded 1 mm spatial resolution. A rigid, lightweight Lexan tube is used to contain a heated mouse bed formed in a semicylindrical shape. Warmed, humidified air as well as gas anesthetic can be introduced and exhausted via the tube. The arrangement facilitates accurate centering and positioning of the SPECT cameras to the animal. The simultaneous acquisition of whole body data and a magnified image of the gut and pancreas within the animal has been applied in a study of /sup 125/I tagged insulin in hyperglycemic and normal mice. In a study of the effectiveness of KI blocking on uptake of iodine in a mouse thyroid, images a phantom of the thyroid and submaxillary glands were of considerable interest.