An economical dual-modality small animal imaging system with application to studies of diabetes

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.