It is generally harmless for children to have chest CT examination once in a while. Long-term and frequent chest CT examination may increase the chances of children’s tissue and organ atrophy, cancer and infertility. 1. Generally no harm: children have to do chest CT examination due to the demand of disease, it is an occasional chest CT examination, its radiation dose is relatively small, generally will not cause any harm to the body. 2. Harmful: Chest CT examination will release rays, which belong to ionizing radiation. Long-term and large amount of exposure to rays may lead to atrophy of tissues and organs, degeneration and necrosis of skin cells, and even cancer; in addition, long-term and large amount of rays may irradiate the genitals, which will increase the chances of infertility in adulthood. Children need to undergo chest CT under the guidance of a doctor, and parents are advised not to let their children undergo CT on their own.