A study published in the New England Journal of Medicine analyzed data from a retrospective cohort of 3,724,623 children born between 1996 and 2016 in six US health systems and in Ontario, Canada.[1][4] The risk of hematological cancers is monitored in connection with the cumulative dose of ionizing radiation from medical imaging such as CT, X-ray, fluoroscopy or nuclear medicine.[1][2] Cumulative dose of radiation to the bone marrow was associated with an increased risk of all hematological cancers, with an excess relative risk of 2.54 per 100 mGy (95% CI: 1.70–3.51, p < 0.001).[1][4] For 30 mGy versus 0 mGy, the relative risk was 1.76 (95% CI: 1.51–2.05).[1] The excess cumulative incidence of hematological cancers by age 21 in children exposed to at least 30 mGy (mean 57 mGy) was 25.6 per 10,000 population.[1][2][4] It was estimated that 10.1% (95% CI: 5.8–14.2%) of hematological cancers in the cohort could be attributed to radiation from medical imaging, with a higher risk at higher doses than with CT.[1][4][5] A study suggests an association between radiation exposure from medical imaging and a small but significantly increased risk of hematological cancers in children and adolescents.[1][4]