Nuclear medicine is the specialized field of medicine that diagnoses and evaluates the anatomical and physiological condition of the body using the unique properties of radionuclides and applies this to treatment. Diagnostic areas include positron CT (PET/CT) with the injection of a trace of an isotope into the human body, the area of imaging acquisition using gamma cameras, and ecosomatics using radioimmunoassay. In addition, radioisotope therapy treats various diseases by using radioisotope drugs that emit alpha rays or beta rays.