PET radiotracer is a type of radioligand that is used for the diagnostic purposes via positron emission tomography imaging technique.

The system detects pairs of gamma rays emitted indirectly by a positron-emitting radionuclide (tracer), which is introduced into the body on a biologically active molecule.

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.

Due to the probable injuries of PET-radiotracers, they could not be administered in the normal doses of the medications.

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.