PET-CT is not very harmful to the human body because the nuclide used is an ultra-short half-life isotope that decays automatically in a very short period of time and is injected at a very low dose. PET-CT in Chinese is called: Positron Emission Computed Tomography. It is the perfect integration of the functions of the most high-grade PET scanner and advanced spiral CT equipment, and is clinically used for the early detection and diagnosis of major diseases in the fields of tumor, brain and heart. The radiation source of PET-CT is mainly the imaging agent 18F-FDG (full name Fluorodeoxyglucose), the nuclide it uses is an ultra-short half-life isotope, which will automatically decay in a very short period of time, and the injected dose is very low, within the safe acceptance range of the human body, and can be quickly discharged from the body by drinking more water. Therefore, the positive aspects of PET-CT examinations far outweigh the effects of radiation, not to mention that the radiation dose is well below the upper safety limit. Whether you need to undergo PET-CT examination, consult your medical professional, do not follow the trend blindly.