Study highlights cancer risk from millions of CT scans

Maine Public - CT scans diagnose afflictions from tumors to kidney stones to life-threatening diseases and injuries, such as aneurysms and blood clots leading to stroke.

But the radiation emitted by this essential diagnostic tool may cause more harm than previously known and could eventually be responsible for roughly 5% of all cancers diagnosed in the U.S. in a single year, a new study finds.

"Medical imaging has potential benefits," said radiologist Dr. Rebecca Smith-Bindman, an epidemiology professor at the University of California, San Francisco, and lead author of the study published Monday in JAMA Internal Medicine. "It has potential harms as well, and it's really important to balance them."

Scientists long ago established that ionizing radiation emitted by computed tomography, or CT, scans increases cancer risk. But, since 2007, use of the imaging technique has surged 35%, the study says, due in part to growth in what Smith-Bindman and her colleagues call "low-value, potentially unnecessary imaging."

Their new research, based on projections from hospitals in 20 U.S. states, estimates that 103,000 cancer diagnoses, or 5% of all cancers, could result from 93 million scans performed in the U.S. in 2023 alone.