Nuclear medicine exams can be considered very safe exams. There are three main unsafe factors that cause various imaging examinations. 1, is the imaging agent, contrast agent, contrast agent and other drugs of the chemical composition of the impact, mainly allergic reactions and toxic reactions; 2, is the radiation caused by radioactivity; 3, is to carry out the examination of the operation process caused by the damage and pain and even danger. Nuclide tracer technology is very sensitive, and the chemical composition of the radioactive drugs used is so small that it is almost negligible, so it will not cause any allergic and toxic reactions. Secondly, the nuclide used in nuclear diagnosis mainly emits gamma rays, which are characterized by strong penetrating ability and small damage to the body. For example, to do nuclear medicine vesicoureteral reflux imaging, the absorbed dose that the patient receives is only 1% of the X-ray cystography, and the X-ray examination is safe for the patient, not to mention the nuclear medicine imaging. Furthermore, the process of nuclear medicine examination is only intravenous or oral injection of radioactive drugs, often in very small volume, without intubation and other operations caused by the injury and pain and risk. Nonetheless, nuclear medicine has strict requirements and regulations to further minimize the occurrence of adverse reactions.