Positron Emission Tomography (PET) is a non-MRI imaging modality that utilizes specific radiotracers (e.g. [18F]FDG, [11C]Glucose) to investigate brain glucose metabolism, neurotransmitter receptor availability, or neurotransmitter levels measured indirectly via competitive receptor binding-displacement (e.g. D2/D3 receptor ligand [11C]raclopride, μ-opioid receptor ligand [11C]carfentanil). The latter ligands more specifically show the difference in binding of the tracer to its target structure with and without intervention and can be used to estimate relative changes in extracellular levels of a specific neurotransmitter.
