In order to evaluate the influence of physical and instrumental limitations of the PET technique on metabolic data, various parameters have been tested. The measurements were done with a whole body PET scanner PC4096-15WB. The dependence on the transaxial resolution of reconstruction filter cut off frequency alpha c was investigated. The high resolution (4.8 mm at r = 0 in the field of view) and the low scatter fraction (less than 5%) of this system yields a higher grey/white matter ratio (3.8:1) than that found with older scanners (2:1). The use of a rotating pin source allows transmission scans to be performed after tracer administration with an error of less than 5%.