Nuclear Medicine is a branch of medicine that uses the nuclear properties of radiation or radionuclide in diagnosing anatomic or pathological condition of the body and treating it with unsealed source radiotherapy beam. Current clinical applications of nuclear medicine in regard of diagnosis are in vivo tests that use a radioisotope for imaging and tracing and in vitro tests that use radioimmunoassay for measuring the sample taken from the patient. Nuclear medicine also contributes to the treatment using radioisotope therapy thus plays an important role in advancement of basic medical science.