Imaging opiate receptors in the human brain with positron emission tomography. Potential applications for drug addiction research.

Positron emission tomography (PET) has been used mostly for the study of brain blood flow and metabolism in normal controls and in a variety of neurological and psychiatric conditions. With the appropriate radiotracers, PET also allows non-invasive imaging and quantification of a growing list of neuroreceptors. 11C-carfentanil and 11C-diprenorphine, 2 potent opiate ligands, have been used to label opiate receptors in vivo in man. Some advantages and limitations of this technique are discussed. PET is a unique tool that could help us understand, at the receptor level, some biochemical aspects of addiction to opiate drugs. Specific questions can be answered, but carefully designed protocols are required.