At high doses, ionizing radiation can cause immediate damage to a person’s body, including, at very high doses, radiation sickness and death. At lower doses, ionizing radiation can cause health effects such as cardiovascular disease and cataracts, as well as cancer. It causes cancer primarily because it damages DNA, which can lead to cancer-causing gene mutations.
Children and adolescents can be more sensitive to the cancer-causing effects of ionizing radiation than adults because their bodies are still growing and developing. Also, children and adolescents usually have more years of life following radiation exposure during which cancer may develop.
More information about the health effects of ionizing radiation exposure is available from the Centers for Disease Control and Prevention (CDC) and the Environmental Protection Agency.