CT examination is currently more commonly used and more advanced means of clinical imaging examination, the diagnosis of disease has significant value, the patient in the CT examination before, during and after the examination have some precautions need to understand, such as is to inform the medical staff of the history of allergies, not to bring metal jewelry and so on. 1. Before CT examination (1) Be prepared psychologically and don’t be overly nervous. (2) Take the initiative to inform the medical staff of your own history of drug allergy and allergic diseases, such as asthma, urticaria, etc.. (3) Women in the preparation for pregnancy, pregnancy, breastfeeding, or patients with severe thyroid disease and severe heart, liver and kidney failure should inform the doctor. (4) If you do enhanced CT, you should fast for 4 hours before the examination according to the doctor’s advice, and if you do the examination of bladder, ureter and other parts of the body, you should hold your urine according to the doctor’s advice. 2. During CT examination (1) Remove high-density or metal objects, such as hairpins, earrings, necklaces, keys, cell phones, belts, etc., from the examination area. (2) According to the physician’s request to cooperate with the position and breath holding, try to avoid unnecessary body movements. (3) Explain to the physician if you are not comfortable during the examination. 3. After CT examination (1) Wait for the doctor’s notice, and leave only after the doctor confirms that the image is correct. (2) Remain in the room for 30 minutes after the enhancement scan is completed, and inform the medical staff promptly if you feel unwell. (3) Drink plenty of water, which will help to expel the contrast medium. (4) Keep the CT examination results in a safe place for comparison at the time of review. It is important to be fully aware of these precautions before undergoing a CT examination and to consult your physician if you are not sure.