YAP-(S)PET small animal scanner: Quantitative results

The University of Ferrara YAP-(S)PET scanner is currently being employed in small animal SPECT studies, with /sup 99m/Tc labeled radiotracers, with the goal of obtaining quantitative activity measurements from region of interest (ROI) analysis of reconstructed images of rats. The measurements will be compared directly with traditional ex vivo measurement of activity with gamma counters. To achieve this goal, the scanner was calibrated relative to a standard Isodose dose calibrator which was calibrated with various certified activity sources. The calibration factor K was defined as the ratio of the activity measured with the Isodose (MBq) and the image count rate (cps). We find K = 0.1346 /spl plusmn/ 0.0008 MBq/cps, with good linearity over a wide range of activities (9-88 MBq). With the calibrated scanner we compared results of activity measurements from images of whole-rat heart acquisitions versus excised hearts. We found good agreement between the two measurements.