Mapping of central D-2 dopamine receptors in man using [C-11]raclopride: PET with anatomic standardization technique

D-2 dopamine receptors are of interest in the pathophysiology of schizophre nia. For group comparisons of neuroreceptor distribution measured by PET on a pixel-by-pixel basis, an anatomic standardization technique is required. The aim of the present study is to build a database of normal Dg dopamine receptor distribution using [C-11]raclopride and an anatomic standardizatio n technique. In each subject, two PET measurements were performed with rapi d bolus injection and with continuous infusion of [C-11]raclopride. The rad ioactivity of the PET images were integrated in the time interval. Integrat ed images were normalized by the radioactivity of the cerebellum, providing a measure of the binding potential (BP) in each pixel. Each PET image was transformed into a standard brain anatomy using a Computerized Brain Atlas system. From the standardized PET images, the sample mean and the SD of the BP were calculated in each pixel. On the anatomically standardized average images for the both rapid bolus injection and continuous infusion, high BP was observed in the putamen and the caudate nucleus, whereas low BP was ob served in the cerebral cortices. The BP for the thalamus and the substantia nigra were slightly higher than those for the cerebral cortices. This regi onal distribution is in good agreement with the distribution of D-2 dopamin e receptors known from in vitro studies. The anatomic standardization techn ique permits to build a database of the normal D-2 dopamine receptor distri bution in the living human brain. This technique can be applied for group c omparisons on a pixel-by-pixel basis. (C) 1999 Academic Press.