Ionizing radiation, which includes radon, x-rays, gamma rays, and other forms of high-energy radiation, has the potential to damage DNA and cause cancer. Epidemiological studies have been conducted to quantify cancer risks based on dose and to establish radiation protection standards. Research has shown that leukemia and most solid cancers can be linked to radiation exposure. Most solid cancer data is described by linear dose response functions, although there may be a decrease in risks with very high doses.
People exposed to radiation early in life have an especially high relative risk for many types of cancer, and the risk of solid, radiation-related cancer seems to persist throughout life. Additionally, some cancer treatments, such as chemotherapy and radiation therapy, can increase a person's risk of developing a different type of cancer later in life. Dr. Nakamura has explained that radiation-induced cancers can occur in both pediatric and adult cancer survivors.
These cancers can arise at a wide range of intervals after cancer treatment, from several years to decades. While these cancers most commonly occur in a wide variety of solid tissues, blood cancers can also arise after radiation therapy. Exposure to ionizing radiation is the best-established and oldest environmental cause of human breast cancer in both men and women. Most scientists agree that no safe dose of radiation has been identified.
Ionizing radiation is any form of radiation with enough energy to separate electrons from atoms (i.e., ionize atoms).