Influence of radioactivity out of the field of view on 3D PET dynamic measurement with [11C]MP4A

This study assessed the influence of radioactivity out of the field of view (out-of-FOV) on the measurement of brain acetylcholinesterase (AChE) activity with tracer [¹¹C] N-methyl-4-piperidyl-acetate by positron emission tomography in the three-dimensional mode. From dynamic scans on a volunteer, it was found that the out-of-FOV radioactivity in the chest was much higher than that of the brain immediately after tracer injection. Representative phantom measurement was performed to quantitate systematic errors due to the out-of-FOV radioactivity using the implemented scatter and attenuation correction and reconstruction algorithms. Resultant errors in the AChE activity (k3 parameter) as calculated by compartment model analysis were found to be less than about one percent in all of the brain regions of interest