Nuclear medicine is a discipline that uses drugs marked with radionuclides to diagnose and treat diseases. It is a science of nuclear technology applied in the field of medicine, an important element of modern medicine and an important symbol of hospital modernization. Nuclear medicine is applicable to the examination and diagnosis of many diseases of human body, and is also very effective in the treatment of some diseases. In developed countries, almost one out of every three patients who visit the hospital has to use the diagnosis and treatment methods of nuclear medicine. Radionuclide tracer technology is the essence of nuclear medicine, and both diagnosis and treatment are closely related to this technology. Radionuclide tracing is a method of attaching radionuclides to certain compounds, which become radiopharmaceuticals, and introducing them into the body so that the doctor can detect the distribution of that drug in the body through instruments outside the body. If you want to understand the heart, you connect the radionuclide to the drug that likes to go to the heart, and if you want to find the tumor you can also connect the radionuclide to the pro-tumor drug. Thus, using radionuclide tracer technology, it is possible to observe whether the metabolism and function of each organ or tissue of the patient is normal.