Overview

• CT scans, especially head CTs, carried the greatest risk, with one or two head CTs linked to a 1.8-fold increase and higher cumulative scans up to 3.5-fold, and about a quarter of subsequent cases among head‑CT patients attributed to radiation.
• Researchers estimate roughly 10% of hematologic cancers in the cohort—about 3,000 cases—were attributable to radiation from diagnostic imaging.
• Across six U.S. health systems and Ontario, 2,961 hematologic malignancies were identified over approximately a decade of follow‑up.
• Children exposed to about 30 milligrays had a 76% higher risk of hematologic cancer compared with those with no documented exposure.
• Authors urge limiting nonessential imaging, using the lowest feasible radiation doses, and favoring ultrasound or MRI when appropriate, noting radiographs deliver far lower doses and were tied to only a small fraction of cases.