Radionuclide tracer technology is the essence of nuclear medicine, and both diagnosis and treatment are closely related to this technology. In fact, we are not unfamiliar with tracer technology. For example, in nature to observe the habits of wild animals – pandas – is the use of tracer technology. Scientists catch the wild panda, put a small radio transmitter on it, people in the room through the instrument can detect the panda’s whereabouts. In this observation, the radio transmitter is a tracer. As you can imagine, as a tracer, it must be very light, very small, and cannot be detected by the panda, nor can it affect and interfere with the panda’s behavior and function. The tracer used in nuclear medicine is not a radio transmitter, but a radionuclide. The radionuclide is attached to certain drugs to become a radiopharmaceutical, which is introduced into the body, and we can detect the distribution and whereabouts of that drug in the body through instruments outside the body. This is radionuclide tracer technology. Like the tracer technology to observe the pandas, the dose of radioactive drugs used for tracing is very small, the body can not be recognized, but also does not affect the behavior and function of the body. Using this technology, if we want to know about the heart, we connect the radionuclide and the drug like to the heart, and if we want to find the tumor, we can also connect the radionuclide to the pro-tumor drug. Using radionuclide tracer technology, the metabolism and function of each organ or tissue of the patient can be observed.