Chest CT plain scan refers to the method of examining chest lesions using CT, which is being used more and more widely and is mainly used clinically for patients’ routine physical examination, or general radiographs to find lung lesions requiring further definite diagnosis. It is used to determine whether the patient has pneumonia, tuberculosis, lung tumor, lung abscess, pneumothorax, pleural effusion, bronchiectasis, pleural hypertrophy, pleural occupancy, etc. It can also determine mediastinal diseases, such as checking whether there are tumors and enlarged lymph nodes in the mediastinum. Chest CT scan is simpler, more convenient to use and less expensive, and is increasingly used in emergency patients.