Radionuclide examination refers to the introduction of radioactive drugs into the human body and the use of radioactive detection instruments to measure the changes of radioactive drugs in the organs over time on the surface of the body, and the computer analysis of the radioactivity profile over this period of time to obtain certain parameters that can assess the function of the organs and diagnose diseases. Generally speaking, after the introduction of radioactive drugs into the human body, the difference in the uptake of radioactive drugs inside and outside the organ or between normal and diseased tissues is used as a basis to obtain images of organs or lesions using imaging instruments to diagnose diseases. In clinical practice, it is often used for lung perfusion scans, lung ventilation scans, or tumor examinations.