A recent study by the Institute of Cancer Research in London indicates that radiation from CT scans may contribute to approximately 103,000 new cancer cases annually in the U.S., including about 9,700 in children.

Roughly 93 million CT (computed tomography) scans are performed on 62 million people each year in the U.S. While these scans are valuable diagnostic tools, they also expose patients to radiation, which can increase the risk of cancer. A new study published in JAMA Internal Medicine estimates that CT scans conducted in 2023 alone could lead to about 103,000 radiation-related cancer cases over patients’ lifetimes.

“If current usage patterns continue, CT-related cancers could make up 5% of all new cancer diagnoses annually,” the study authors warned.

Children and adolescents face a higher relative risk due to their developing tissues, but adults—who undergo the majority of CT scans—make up the bulk of projected cases. The greatest number of cancers are expected to stem from abdominal and pelvic CTs in adults, followed by chest scans. The most frequently projected cancer types include lung, colon, leukemia, and bladder cancers. For women, breast cancer was the second most common.

An editorial accompanying the study emphasized how deeply embedded CT scanning is in modern medicine. Described as fast, accurate, and cost-effective, CT has become a mainstay in diagnosing everything from trauma to cancer. However, the editorial also stressed the need to weigh its benefits against potential long-term harms.

The authors called for action, likening the cancer risk from CT scans to other major health threats like alcohol use and obesity. They recommended using non-radiation alternatives when possible, reducing radiation doses, and training clinicians to avoid unnecessary scans.

Concerns about overuse aren’t new. A 2015 Consumer Reports investigation found that up to one-third of CT scans may be unnecessary, needlessly exposing patients to radiation.