With the development of new tracers, various neurotransmitter receptors can be imaged in humans including extrastriatal dopamine receptors, serotonin receptors and transporters. In most studies, tracer is intravenously administered as a bolus and the measurement is performed under non-equilibrium conditions in which activities in both plasma and brain change dynamically over time. Under these circumstances with complicated changes, enough caution must be paid for the accuracy of the measurement and the interpretation of the results. For example, the crude measurement at one fixed time point is influenced by between-subject differences in clearance and cerebral blood flow. The influence of neurotransmitter levels on the binding of tracer is different between non-equilibrium and equilibrium conditions. This note warns those who are relatively new to this field about the possibilities of misinterpreting imaging results by showing illustrative examples.
ASJC Scopus subject areas
- Psychiatry and Mental health