Cancer Risk Associated With Radiation Doses Used for CT Scans in Pediatric and General Hospitals.

Objective: Describe radiation doses used in common computed tomography (CT) scans by hospital type and estimate the impact of observed dose differences on associated lifetime cancer risk.

Patients and methods: Retrospective cohort study in patients aged <21 years undergoing 192 185 CT scans included in a large CT dose registry. Scans were assigned to CT category based on body region imaged, clinical indication, and radiation doses used (routine head, low-dose head, neck, routine chest, routine abdomen). Median radiation doses were compared among hospital types. Excess cancer risks were estimated using the National Cancer Institute Cancer Risk calculator.

Results: For routine head and abdomen and pelvis CT in children aged 12 to <21 years (45% of all scans), radiation doses were 20% to 30% lower in pediatric hospitals (P < .001). In children aged <12 years, routine head doses were 20% lower in pediatric hospitals; abdomen doses varied by age. Pediatric hospitals used radiation doses 30% to 100% higher in children <12 undergoing chest CT (P < .001). An estimated 5500 excess cancers are associated with radiation from CT performed annually in children. An estimated 1200 cancers are associated with differences in dosing.

Conclusions: Radiation doses used for pediatric CT are associated with the development of an estimated 5500 future cancers annually. Differences in radiation doses are associated with an excess estimated 1200 radiation-associated cancers. Further study is needed to determine why dose variation exists in children and adolescents and if optimal doses are being used for the clinical indication of the examination.