The first choice for lung screening is still CT. spiral CT of the chest can detect many diseases, commonly tuberculosis, inflammation, tumors, etc. For early lung cancer screening, chest spiral CT is currently used for scanning, and the condition is a low-dose scanning method to check early lung cancer lesions. Chest CT can also check mediastinal occupancy, such as soft tissue mass shadow in the anterior mediastinum, and chest enhancement CT can be done to distinguish its relationship with surrounding tissues and see what this lesion tends to be, commonly thymoma. In addition, CT of the chest can also be applied to the examination of bronchial foreign bodies in pediatric patients, which can clarify whether there is any obvious foreign body in the trachea.