There is no specific time interval for CT exams, and this needs to be considered depending on the patient’s condition. For example, if a small nodule is found on the lung and the nodule is not in good shape, it may be necessary to review the CT once in a short period of time, usually once every two months, to check for changes in the nodule. If the nodule has a brighter shape and there is no change after the review, the next review may take longer, or even 1-2 years, but in some patients, such as those with cerebral hemorrhage, the doctor will decide how often to review the CT depending on the patient’s condition. Therefore, there is no specific time interval for how often to do CT, and it is decided according to the condition.