The radiation of CT will disappear when the CT machine ends the examination, because the radiation produced by the CT machine only radiates to the human body during the examination, and it ends instantly after the examination, and it will not exist in the human body all the time. Radiation damage to the human body mainly refers to its ionizing radiation to the human body, will produce some damage to the human body’s cells, but this kind of damage will generally be gradually repaired, if it is not the amount of radiation is particularly large, irradiation time is particularly long, the problem is not big. So if a patient has a CT 2-3 times a year, even if there is radiation on the human body is not very harmful. People live in an environment where there is a lot of radiation, such as computers, cell phones, etc., so patients do not have to talk about radiation, to correctly understand the role of CT on the human body examination, and to weigh the pros and cons.