Performance characteristics of an eight-ring whole body PET scanner.

The technical characteristics of the multislice whole-body positron emission tomographic scanner (model PC4096-15WB Scanditronix) and its performance parameters are described. Spatial resolution at the center of the field of view was found to be 4.9 mm in-plane and 4.6 mm (cross slices) and 6.0 mm (direct slices) in the axial direction. The sensitivity for true and scattered coincidences is approximately 5,000 cps for direct slices and 7,100 cps for cross slices. At an activity concentration of 37 kBq/ml the system deadtime was approximately 5%. By measuring a uniform phantom with a cold cylindrical insert (5.0 cm diameter), the scatter fraction was found to be approximately 5%. The mean global uniformity over all 15 slices was 6.5%, whereas the local uniformity was found to be 4.3%. No systematic nonuniformities were observed. Finally, various methods for attenuation correction (transmission scan, contour finding, ellipse) were utilized to test their effects on the resulting reconstructed images.