Nuclear medicine is a specialized field of medicine that diagnoses physiological and pathological conditions of the body using radioactive isotopes and treats various diseases. Department of Nuclear Medicine of Gachon University Gil Medical Center can do early diagnosis of coronary heart disease and increase prevention of stroke and epilepsy seizure. For the accurate diagnosis and treatment of various diseases such as confirming the location of patients as well as early diagnosis and observation of various cancers, we operate a cardiac nuclear medicine, brain neuronuclear medicine and tumor nuclear medicine imaging room, blood test room, radioactive iodine treatment room, and isotope treatment room. In addition, as the radiation safety management officer of the entire hospital, we play a role of safety management in the use of radiation.