Table 1: PET applications for molecular brain imaging and examples of various PET radiotracers.
Brain activity: [15O] water for cerebral blood flow (Zhang et al., 2014) and [18F] fluorodeoxyglucose (FDG) for neurometabolic glucose use (Villien et al., 2014). Neurotransmitter receptors: Dopamine D2/D3 antagonists [11C]raclopride (Volkow et al., 1994) and [18F]fallypride (Slifstein et al., 2010). Serotonin 5- HT2A agonist [11C]Cimbi-36 (Ettrup et al., 2014). Neuroinflammation: Translocator protein (TSPO) tracer [18F]GE-180 (Vomacka et al., 2017). Neurodegeneration: Neurofibrillary tau protein tracer [18F]MK-6240 (Hostetler et al., 2016). Neuro-oncology: [18F]fluoroethyltyrosine (FET) and [18F]FDG for assessing brain tumors (Pauleit et al., 2009). Drug target engagement: Radiolabeled [11C]psilocin (Amatamey et al., 1998). Psilocybin displacement of [11C] Cimbi-36 at 5-HT2A receptors (Madsen et al., 2019). Tracking transgene expression: Enzyme-based HSV1-tk reporter [124I]2′-fluoro-2′-deoxy-1-β-D-arabinofuranosyl-5-iodouracil (FIAU) (Tjuvajev et al., 2002). Receptor based dopamine D2 reporter [18F]fluoroethylspiperone (FESP) (Liang et al., 2001).
| Applications | Description | Radiotracer examples |
|---|---|---|
| Brain activity | Measure cerebral blood flow or glucose metabolism as a proxy for brain activity | [15O] water (cerebral blood flow), [18F]FDG (glucose metabolism) |
| Neurotransmitter receptors and transporters | Evaluate neurotransmitter receptor availability and release using radioligands selective for endogenous receptors and transporters | Dopamine: [11C]raclopride and [18F]fallypride Serotonin (5-HT): [11C]Cimbi-36 |
| Neuroinflammation and Neurodegeneration | Assess neuroinflammation and neurodegeneration using selective radioligands to probe relevant biomarker proteins | Translocator protein (TSPO) tracers: [18F]GE-180 Neurofibrillary tau protein: [18F]MK-6240 |
| Neuro-oncology | Diagnose and monitor cancer in peripheral and central nervous system using relevant biomarkers | [18F] FET for tumors, [18F] FDG for abnormal glucose metabolism |
| Drug target engagement | Evaluate binding of radiolabeled drugs or blockade/displacement of receptor selective radioligands | Radiolabeled [11C]psilocin or displacement of [11C]Cimbi-36 at 5-HT2A receptors |
| Tracking transgene expression | Track transgene delivery and expression by co-packaging with PET-compatible reporter genes | Enzyme based: HSV1-tk reporter with [124I]FIAU. Receptor based: Dopamine D2 receptor reporter with [18F]FESP |