Radioligands for Imaging of the CNS Acetylcholinergic System

There is an extensive and growing literature on PET imaging of the CNS cholinergic system. PET radiotracers have been developed for diverse molecular targets in the cholinergic system, and many have progressed to human imaging. To date, these have been used mainly in a research, rather than clinical context. But the implication that the cholinergic system plays a role in many neuropsychiatric and neurodegenerative conditions has driven a continued search for new tracers with desirable pharmacokinetic and target specificity properties. Here, we present a brief introduction to the organization of the CNS cholinergic system, some of the evidence that its dysregulation may contribute to pathological conditions of the brain, a brief overview of quantitative outcome measures for cholinergic brain imaging, and a description of tracers and targets for the cholinergic system with reviews of some of the clinical research utilizing these cholinergic tracers.