Lit Matters 1: Lifetime cancer risk from CT

CT imaging is a major source of medical ionizing radiation, and current U.S. use may account for about 5% of future annual cancer diagnoses if present patterns persist. Risk is highest per exam in younger patients, but adults drive most projected cancers because CT volume is so high.

Lifetime cancer risk from CT

• Population radiation burden: Modeled 2023 U.S. CT use totaled 93 million exams in 61.5 million patients, with roughly 103,000 projected radiation-induced cancers if current imaging patterns and doses continue.
• Adult volume dominates harm: Children carry higher per-exam risk, but adults account for 91% of projected cancers because nearly 90 million scans were performed in adults.
• Highest-risk scan groups: Abdomen-pelvis CT generated the largest share of projected adult cancers at 40%, while head CT drove 53% of projected cancers in children.
• Age-related risk gradient: Radiation-related cancer risk falls with increasing age at exposure; in girls younger than 1 year, the modeled risk approached 20 cancers per 1000 CT exams.
• Most common projected cancers: Lung cancer led the adult projections, followed by colon cancer and leukemia; thyroid cancer was the leading projected malignancy in children, a pattern we put in clinical context in the episode.
• Practice implication: CT remains diagnostically invaluable, but this paper argues for stricter indication discipline and dose stewardship because delayed radiation harm is real and rarely attributable at the bedside.