Multi-layer spiral CT can examine the whole body tissues and organs, such as head, neck, chest, abdomen, pelvis, spine, extremities, heart and large blood vessels, etc. Multi-layer spiral CT can be used for examination. The more layers, the faster the speed and the higher the image quality, the better the diagnosis and the important basis for the patient. Among all multi-layer spiral CTs, the mid- and high-end CTs with 64 layers or more can not only do whole-body examinations of various parts of the body, but also have the advantage of being able to perform CT angiography on the heart and large blood vessels; they can also perform a large-scope scan for patients with chest pain triad. For emergency patients, such as those with trauma, it is clinically important to be able to show the patient’s lesions from a single wide-scale scan of the chest and abdomen.