Positron emission tomography (PET) is an unsurpassed method for imaging human biochemical
and physiological processes in vivo.
PET is growingly used in clinical medicine in patients with cancer, cardiovascular, neurological or inflammatory diseases.
Unlimited number of natural substrates, substrate analogs and drugs can be labeled for use with PET.
This labeling does not change their chemical or biological properties.
Minute amounts of biologically active compounds are labeled with positron emitting radionuclides
(11C, 15O, 13N, 68Ga, 64Cu or 18F) and then administered to the subjects. The temporal and spatial distribution of these tracers within the body is measured with PET.
PET combined with tracer kinetic models measures blood flow, membrane transport, metabolism
and ligand receptor interactions noninvasively and quantitatively in human.
PET has been used extensively to study cellular metabolism and molecular interactions in the brain, heart and malignant tumors.