Physical characteristics of a small diameter positron emission tomograph

The physical performance of a novel, 11.7-cm ring diameter positron emission tomograph developed to quantify in vivo tracer kinetic data from small animals and the human radial artery, has been characterized. The system incorporates 16 of the latest-generation CTI/Siemens high-resolution bismuth germanate (BGO) block detectors. Interring septa are not utilized, enabling acquisition and reconstruction of 3-D data sets. Using an energy threshold of 250 keV, the optimal mean transaxial spatial resolution is 2.8 mm FWHM at the center of the field-of-view, degrading to 4.8 and 6.0 mm at 2 and 4 cm from the center, respectively. The optimal axial resolution is 4.7 mm FWHM. The scanner has a maximal absolute sensitivity of 7.9%. The sensitivity measured with a 5.2-cm uniform cylinder is 450 Kcps/(μCi/ml). Scans of rat brain and the radial artery indicate the system´s ability to produce kinetic data with high spatial and temporal resolutions