BETHESDA, Md., June 7 (UPI) -- Children and teens scanned multiple times by computed tomography have a somewhat increased risk of leukemia and brain tumors, U.S. and British researchers say.
Senior investigator Amy Berrington de Gonzalez of the Division of Cancer Epidemiology and Genetics at the National Cancer Institute and colleagues at Newcastle University in England obtained CT exams from radiology departments in hospitals across Britain and linked them to data on cancer diagnoses and deaths.
The study looked at 175,000 children and young adults who underwent CT scans at British hospitals from birth to 22 years of age from 1985 to 2002.
The study, published online in The Lancet, found a clear relationship between the increase in cancer risk and increasing cumulative dose of radiation. A three-fold increase in the risk of brain tumors appeared following a cumulative absorbed dose to the head of 50 to 60 milligray -- a unit of estimated absorbed dose of ionizing radiation.
"Ours is the first population-based study to capture data on every CT scan to an individual during childhood or young adulthood and then measure the subsequent cancer risk," the researchers said in a statement.
The researchers emphasize that when a child suffers a major head injury or develops a life-threatening illness, the benefits of clinically appropriate CT scans should outweigh future cancer risks.
The investigators estimated that for every 10,000 head CT scans performed on children age 10 years or younger, one case of leukemia and one brain tumor would occur in the decade following the first CT, beyond what would have been expected had no CT scans been performed.
