Under normal circumstances the human body is relatively safe to do 2-3 times a year CT scan, because the radiation dose of a CT scan is about 10mSv, and the safe value of the amount of radiation a person receives in a year is 50mSv, so 2-3 times CT scan is not a problem. In the case of enhanced CT it is generally recommended not to exceed two times, which is a relatively safe situation, because the radiation dose of enhanced CT is more than that of plain CT. However, there are patients who belong to special cases, such as tumor patients who need 2-3 months or even more frequent CT examinations, at which time it is necessary to weigh the pros and cons. Even if CT is done more often, it is not a big problem, so patients do not need to be too nervous. If possible, doctors will also choose other ways to examine patients with less radiation.