Cyclotron-produced. The most clinically utilized PET radionuclide. The positron annihilates with an electron at close range, producing two 511 keV coincident photons at 180° — detected simultaneously by PET scanner rings (coincidence detection).
FDG (2-[F-18]-fluoro-2-deoxy-D-glucose):
- Glucose analogue phosphorylated by hexokinase → FDG-6-phosphate, which is trapped (not metabolized further in most tissues)
- Uptake proportional to glucose metabolism — high in malignant cells, brain, heart, activated macrophages
- Patient prep: fasting 4–6 hours, blood glucose <200 mg/dL; hyperglycemia → competitive inhibition by glucose → reduced tumor uptake
- Cardiac viability: FDG uptake in a region of reduced perfusion = hibernating/stunned myocardium (viable); absent FDG + reduced perfusion = scar
Amyloid PET: positive scan (cortical retention of tracer) = amyloid plaque burden consistent with Alzheimer’s; negative scan effectively excludes Alzheimer’s pathology. Used to guide anti-amyloid therapy eligibility (lecanemab, donanemab).
PSMA PET: prostate-specific membrane antigen overexpressed on prostate cancer cells. Superior to conventional imaging (bone scan + CT) for detecting biochemical recurrence at low PSA levels and for initial staging of high-risk disease.