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.

The authors have developed a multimodality system for imaging the biodistribution of biologically interesting ligands tagged with /sup 125/I. By incorporating a small fluoroscope as an additional modality, they have enhanced their small animal nuclear imaging system to include both X-rays and images from two Hamamatsu R3292 5" diameter position sensitive photomultiplier tubes (PSPMT) viewing pixel...

The detector group at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) and the Biology, Physics and Applied Sciences Departments at the College of William and Mary are collaborating on the development of a miniature dual modality SPECT-CT system for mouse imaging. The detector heads of the SPECT subsystem are capable of imaging the gamma- and X-ray emissions (28-35 keV) of the radioactive isotope iodine-125 (Ie 125). Two different sets of I-125 imaging detectors are configured on a gantry that has an open-barrel type design. One set of detector heads is based on the 1 inch square Hamamatsu R5900-M64 position sensitive photomultiplier tube coupled to crystal scintillator arrays. The other detector heads configured on the gantry are two 5-inch diameter Hamamatsu R3292-based compact gamma cameras. The X-ray radiographic projections will be obtained using a LIXI Inc. model LF-85-503-OS X-ray imaging system that has an active area of 5.5 cm in diameter. The open-barrel shaped gantry facilitates the positioning of various mini gamma-ray imaging detectors and the X-ray system. The data acquisition and gantry control is interfaced through a Macintosh G3 workstation. SPECT reconstruction results using the R5900 based detector are presented

We have developed an economical dual-modality nuclear imaging system comprised of two Hamamatsu 125 mm diameter position sensitive photomultiplier tubes (PSPMT) viewing pixelated scintillators and a small fluoroscopic X-ray system (Lixi, Inc.). Collimators placed between the animal and the scintillators can be readily interchanged and include CuBe parallel-hole collimators with a range of resolution/sensitivity combinations as well as brass pinhole collimators with various pinhole diameters. The small X-ray fluoroscope provides 5 cm diameter images, several of which can readily be combined to provide structural information from the animal under study. The system has been used to follow the metabolism of compounds tagged with /sup 125/I. Biological information has been obtained on the uptake of tagged insulin and tumor necrosis factor-alpha (TNF/spl alpha/) thus demonstrating the applicability of this system for in vivo analysis of diseases such as diabetes.