The rapidly expanding field of nuclear medicine involves the insertion of radioactive substances into the patient. These may be attached to various pharmaceuticals, and the location of the isotope is recorded using gamma detectors. PET scans utilise isotopes which undergo beta + decay. The antiparallel gamma photons resulting from the electron-positron annihilation is recorded by the detector.
Theses slides outline the use of radioisotopes in both conventional and PET nuclear imaging.