Performance Figures and Images from the Therascan 3128 Positron Emission Tomograph

The THERASCAN 3128 system has been designed to study cerebral function using positron emission tomography (PET) methods. Two rings of bismuth germanate (BGO) detectors define three image planes per scan. For the low resolution mode image resolution is 19 mm × 19 mm × 20 mm (axial) and the direct slice sensitivity for true coincidences is 88 kcps/(¿Ci. cm-3). In the high resolution mode image resolution is 12 mm × 12 mm × 12 mm with a sensitivity of 33 kcps/(¿Ci. cm-3). Deconvolution methods used to remove scattered events have been verified by repeated imaging of a phantom designed to provide a wide variation in contrast with time. Clinical images from 18F-2-fluorodeoxyglucose (FDG) and 15O studies are presented as practical examples of system performance and to illustrate the useful information obtained from coronal/sagittal sectioning of closely spaced transverse images.