Sensitivity evaluation of positron emission tomographs.

Applying the recommended guidelines of the Instrumentation Group of the EEC Concerted Action, the sensitivity of an ECAT 933/4-16 scanner was determined. Several filters were used to reconstruct the images. On the images regions of interest (ROIs) were defined, and the ROI-counts were compared to the specific activity in the phantom. Whereas the uncorrected sensitivity was not influenced by the reconstruction filters, the sensitivity corrected for the scatter fraction appeared to be dependent on the reconstruction filter. Images reconstructed with a non-smoothing filter (Ramp filter, Shepp filter) yielded a higher sensitivity due to the lower reconstructed scatter fraction.