Nuclear myocardial imaging is also called radionuclide examination, using 201 thallium or technetium 99, two radioactive substances, after intravenous injection of normal myocardium due to absorption of radioactive substances, ischemic myocardium is poorly visualized, serious damage to the myocardium may not be visualized at all, and then determine the myocardial ischemia, damage and necrosis. This is a kind of tracer technique, using a small dose of radioactive material, which is not harmful to human body and has some value in the diagnosis of coronary heart disease and myocarditis. Myocardial ischemia is caused by atherosclerosis of coronary arteries, and some people have no symptoms at the early stage of plaque formation, while some people only have slight chest tightness or panic after activity or emotional excitement. At this time, doing radionuclide examination can make preliminary assessment of the ischemic myocardium, which can achieve the effect of early diagnosis, early prevention and early treatment. Once myocardial ischemia or damage is determined, drug treatment is initiated.