[Implementation of a measurement protocol to evaluate system parameters in positron emission tomography]

To evaluate system parameters in PET measurements, several different activity ratios of the investigated phantom must be analyzed. The aim of this study was to develop a measurement protocol which requires just one filling of the phantom to measure adequate image contrasts and count ranges. We used 11C for the hollow spheres and 18F for the background of the whole-body PET phantom. Because of the different half-lives of the radionuclides, the dynamic acquisition of the frames (duration compensated for 18F decay) realizes various activity ratios between the spheres and the constant background. By summing up different frames, the counts in the background can also be varied. The presented method reduces the radiation exposure of the staff and economizes the use of the tomograph.