2-D and 3-D Imaging of Small Animals a High Resolution Detector for PET Radial and the Human Artery with

The performance of a pair of multicrystal, high res- olution, bismuth germanate (BGO) block detectors for positron emission tomography (PET) has been investigated. Utilizing the detectors at a separation of 100 mm, the spatial resolutions and count rate response of the block have been measured. These measurements indicate maximum spatial resolutions of 3.6 and 4.5 mm (FWHM) in the two axes of the block and a maximum coincidence rate of 3400 cps. The system has been used to observe the regional kinetics of positron-emitting radionuclides in the rat brain and the human radial artery. Designs for a small diameter, no-septa tomograph incorporating these detectors have been considered. Simulations performed demonstrate the possibilities of following tracer uptake within the rat brain and radial artery. 3-D tomographic data-sets of a 20 mm uniform cylinder, obtained from rotating the two blocks, indicate good uniformity in the field of view (FOV) of 25 mm.