The interval between CT examinations depends on the patient’s condition, and the number of CT examinations should be minimized as long as the condition allows. CT examinations can cause some radioactive damage to the human body, and the degree of damage depends on the dose of radiation exposure during the examination. The damage caused by normal physical examinations and CT examinations for diseases is very slight, far below the threshold of radiation damage to the human body, and can be neglected. Patients can do the necessary CT examinations during annual physical examinations, and further enhanced CT and CTA examinations are also needed when suspicious lesions are found to obtain a clearer diagnosis and help in the treatment of diseases. For example, if a suspicious lung nodule is found in a chest CT examination, an enhanced CT examination can be done to further clarify the nature of the nodule. You should be fully prepared before CT examination, keep the same position during the examination, fully cooperate with the doctor, and try to avoid unnecessary repeated examinations.