Common Medical Scan ‘Routinely’ Delivers Excess Radiation, May Cause 36,000 Cases of Cancer a Year
Cara Lynn Shultz
Thu, March 13, 2025 at 11:29 AM EDT
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Stock image of a CT scanner.
CT scans ‘routinely’ deliver up to three times the radiation they should, which can lead to 36,000 cases of cancer a year.
“In the ninety million CT scans performed annually in the U.S., many patients still routinely receive radiation doses two or three times what they should,” Dr. Rebecca Smith-Bindman, a University of California San Francisco professor in residence of epidemiology, biostatistics, obstetrics, gynecology and reproductive medicine, said in a release from UCSF.
CT (short for computed tomography, and often pronounced as “cat”) scans use a mix of X-ray and computer technology to provide detailed images of the body, John Hopkins Medicine explains, adding that “the amount of radiation dose used in a CT scan is small.”
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Stock image of an older man going into a CT scanner.
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But as Smith-Bindman says, radiologists are defaulting to using higher radiation doses when a lower dose would suffice; while the higher doses generally mean more detailed scans, they’re not always required for the specific diagnosis.
When testing approximately 48,000 CT machines in 17 hospitals, Smith-Bindman’s research found that 30% of the scanners emitted too high a radiation dose — and image quality was never a concern.
As she says, this excess radiation, “will lead to cancer in a small percentage of patients, approximately 36,000 cancers every year. This means that CT causes two percent of annual cancer, and we can reduce that risk substantially without reducing the value of the scans.”
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She is working with the Centers for Medicare & Medicaid Services (CMS) to better regulate the radiation used by these machines. “Historically, it was thought that each radiologist could decide on their own what they felt was the appropriate radiation dose and image quality for each scan, as opposed to having standards that everyone follows. This led to unacceptable variation among providers,” Smith-Bindman said.
Her team has created software that will be provided, free of charge, to hospitals to help them ensure they are using the appropriate radiation dose without sacrificing image quality.
“No one intentionally harms their patients; they just haven’t been paying attention to radiation dose.” |
