ABSTRACT
Positron emission tomography (PET) is a noninvasive nuclear imaging technique that produces images of the metabolic activity of living organisms on the biochemical level. These physiological images are detected by introducing a short-lived positron-emitting radioactive tracer, or radiopharmaceutical, by either intravenous injection or inhalation. Images are created using a process called radioactive labeling in which one atom in a molecule is replaced by a radioactive radionucleotide.
