Positron emission tomography (PET) in the study of dopamine receptors in the primate brain: evaluation of a kinetic model using11C-N-methyl-spiperone

Abstract

— The regional kinetics of ¹¹C‐N‐methyl‐spiperone (¹¹C‐NMSP) are described in the monkey brain under tracer conditions and after displacement and protection experiments. The primary aim of the study was to investigate different methodological problems associated with use of ¹¹C‐NMSP in the quantitation of receptor properties before applying the method in clinical research. Special emphasis was placed on the evaluation of different mathematical approximations of a general compartment model. Different mathematical procedures are described and the results indicate that the approximations performed are reasonable. The simplest method for obtaining a reliable measurement of the rate constant k₃ (which is ∼ proportional to the number of receptors) and k₄ (the receptor dissociation rate constant) uses the radioactivity in the cerebellum as a measure of the tissue concentration of ligand equilibrating with the receptor compartment.