Positron emission tomography tracer (PET tracer)

A **positron emission tomography tracer** (PET tracer) refers collectively to a wide variety of radioactive molecules (radiotracers or radiopharmaceuticals) that are labeled with positron-emitting isotopes (such as fluorine-18, carbon-11, oxygen-15, nitrogen-13) for the purpose of producing PET images of metabolic, biochemical, and physiological activity in vivo[1][3][4][5][7][9]. These compounds are *not* molecular targets themselves but are used as diagnostic agents to bind or interact with specific biological processes of interest (e.g., glucose metabolism, perfusion, neurotransmitter activity), depending on the chemical structure of the tracer and its intended imaging application[1][5][9]. PET tracers are designed to target specific molecular pathways or tissue characteristics for visualization, with the most common example being 18F-fluorodeoxyglucose (FDG) for imaging glucose metabolism, particularly in oncology[5][1]. Other tracers, such as [18F]NaF (bone imaging), [13N]NH3 (cardiac imaging), or disease protein-specific probes (e.g., [18F]-flortaucipir for tau aggregates in Alzheimer’s disease), represent distinct molecules, each with its own molecular target and specificity[2][6][8]. **In summary:** "Positron emission tomography tracer" is a generic descriptor for a class of compounds, *not* a molecular target, receptor, enzyme, or protein, and is therefore not appropriate as a structured "target" entry[1][5][9].

Other names

PET tracerradiotracer (PET)positron-emitting radiopharmaceuticalPET probePET imaging agent