Risk of hematological malignancies from CT radiation exposure in children, adolescents, and young adults

Over one million European children undergo computed tomography (CT) scans annually. Although moderate- to high-dose ionizing radiation exposure is an established risk factor for hematologic malignancies, risks at CT examination dose levels remain uncertain. The multinational EPI-CT trial included 948,174 individuals who underwent CT examinations before age 22 years in nine European countries. Follow-up of these patients showed an association between cumulative dose and risk of all hematological malignancies, with an excess relative risk of 1.96 (95% CI 1.11-3.12) per 100 mGy to the bone marrow. Similar estimates were obtained for lymphoid and myeloid malignancies. Results suggest that for every 10,000 children examined today (mean dose 8 mGy), 1 to 2 persons are expected to develop a hematological malignancy attributable to radiation exposure in the subsequent 12 years. The authors conclude that these results highlight the need for continued justification of pediatric CT examinations and optimization of doses.