A Review on the Positron Emission Tomography Radiotracers

Review Article

Abstract

Positron Emission Tomography (PET) is a non-invasive, quantitative molecular imaging modality that provides functional insights into in vivo biological and biochemical processes. The technology relies on the administration of radiotracers, which are biologically active molecules labeled with a short-lived positron-emitting radionuclide. Following systemic distribution, the tracer accumulates in target tissues based on specific physiological or pathological pathways. The radionuclide's decay produces a positron, which annihilates with a local electron, releasing two collinear 511 keV gamma photons. These photons are detected by the PET scanner, allowing for the three-dimensional reconstruction of the tracer's concentration. This technique has profoundly impacted clinical practice and research. In oncology, [¹⁸F]Fluorodeoxyglucose ([¹⁸F]FDG) remains the cornerstone for staging, restaging, and monitoring therapeutic response by mapping glucose metabolism. In neurology, specific radioligands permit the quantification of neurotransmitter receptor densities, protein aggregates, and metabolic dysfunction in disorders like schizophrenia and Alzheimer's disease. For cardiology, PET assesses myocardial perfusion and, critically, metabolic viability. Moreover, PET is an indispensable tool in pharmaceutical sciences, enabling in vivo characterization of drug pharmacokinetics, target engagement, and pharmacodynamic effects in early-phase clinical trials. The continued development of novel tracers targeting specific molecular events propels its utility in precision medicine