In general, CT scan does not require fasting, except for abdominal scan, where fasting is recommended. It is not easy to observe the gallbladder lesion because the gallbladder will contract after eating, as the abdominal scan depends on the gallbladder. CT scan requires the patient to wear clothes and accessories, such as clothes with no metal objects on them, which will produce artifacts. The patient is required not to move, mainly for fear of artifacts from motion, so the patient should be absolutely braked. If scanning the chest and abdomen, the patient is required to cooperate with the breathing movement to scan, so that a better image can be obtained, which is conducive to the examination and judgment of the disease.