PET radiotracer is a type of

radioligand A radioligand is a radioactive biochemical substance (in particular, a ligand (biochemistry), ligand that is radioactive tracer, radiolabeled) that is used for diagnosis or for research-oriented study of the receptor (biochemistry), receptor system ...

that is used for the diagnostic purposes via positron emission tomography imaging technique.

Mechanism

PET is a

functional imaging Functional imaging (or physiological imaging) is a medical imaging technique of detecting or measuring changes in metabolism, blood flow, regional chemical composition, and absorption. As opposed to structural imaging, functional imaging center ...

technique that produces a three-dimensional image of functional processes in the body. The system detects pairs of

gamma ray A gamma ray, also known as gamma radiation (symbol γ or \gamma), is a penetrating form of electromagnetic radiation arising from the radioactive decay of atomic nuclei. It consists of the shortest wavelength electromagnetic waves, typically ...

s emitted indirectly by a positron-emitting radionuclide ( tracer), which is introduced into the body on a biologically active molecule.

Pharmacology

In ''in vivo'' systems it is often used to quantify the binding of a test molecule to the binding site of radioligand. The higher the affinity of the molecule the more radioligand is displaced from the binding site and the increasing radioactive decay can be measured by

scintillography Scintigraphy (from Latin ''scintilla'', "spark"), also known as a gamma scan, is a diagnostic test in nuclear medicine, where radioisotopes attached to drugs that travel to a specific organ or tissue (radiopharmaceuticals) are taken internally and ...

. This assay is commonly used to calculate

binding constant The binding constant, or affinity constant/association constant, is a special case of the equilibrium constant ''K'', and is the inverse of the dissociation constant. It is associated with the binding and unbinding reaction of receptor (R) and li ...

of molecules to receptors. Due to the probable injuries of PET-radiotracers, they could not be administrated in the normal doses of the medications. Therefore, the binding affinity (P_KD) of the PET-tracers must be high. In addition, since via the PET imaging technique is desired to investigate a function accurately, the selectivity of bindings to the specific targets is very important.

References

{{Diagnostic radiopharmaceuticals Positron emission tomography Neuroimaging Nuclear medicine Radiopharmaceuticals Medicinal radiochemistry Chemicals in medicine

Mechanism

Pharmacology

See also

References