According to a 2025 study published in JAMA Internal Medicine and reported by VeryWell Health, researchers from UCSF analyzed data from 93 million CT scans performed in the U.S. in 2023 and projected that these could lead to over 100,000 future cancer cases, accounting for roughly 5% of all new cancer diagnoses annually.

The risk comes from ionizing radiation, which CT scans use to produce detailed internal images. While a single scan poses minimal risk, the cumulative exposure, especially from multiphase scans or repeated imaging, can significantly increase cancer risk over time. That said, experts emphasize that CT scans remain life-saving diagnostic tools, and the goal isn’t to eliminate them but to optimize their use. According to the American College of Radiology, newer CT technologies use 30–50% less radiation than older models