This medical test may cause cancer due to ‘unfathomable’ mistake — and it’s performed 93M times a year in the US

As the federal government investigates America’s chronic disease epidemic, some experts are warning that a popular diagnostic tool may be a contributing factor.

CT scans, a go-to for diagnosing everything from tumors to infections to bone fractures, are facing increased scrutiny. Experts say the radiation doses they deliver can vary dramatically — and often exceed what’s necessary.

“Many patients still routinely receive radiation doses two or three times what they should,” said Dr. Rebecca Smith-Bindman, a professor at the University of California-San Francisco medical school. “That will lead to cancer in a small percentage of patients, approximately 36,000 cancers every year.” 

What are CT scans? 

Computerized tomography is a medical imaging procedure that uses X-rays to create detailed, three-dimensional images of the body.

Every year, an estimated 93 million CT scans are performed in the US, up from just 3 million in 1980. ​​The surge isn’t accidental — these machines have revolutionized diagnostics, reducing the need for invasive procedures like exploratory surgeries, per Harvard Health. 

Despite their rise in use, experts warn that radiation doses from CT scans vary widely among clinics, with little oversight. One machine can expose a patient to 10 or 15 times as much radiation as another, according to NBC News.

“It’s unfathomable,” Smith-Bindman told NBC. “We keep doing more and more CTs, and the doses keep going up.”

Researchers have also noted that US doctors order far more imaging than physicians in other parts of the world, arguing that some of it is unnecessary and potentially dangerous.

What are the risks of CT scans? 

CT scans use ionizing radiation, which can damage DNA. While most of the damage is repaired by cells, some errors can cause DNA mutations, potentially leading to cancer down the road.

The lifetime cancer risk from CT scans is generally considered low, but research suggests the risk increases for patients who undergo multiple scans throughout their lives.

One study found that the lifetime cancer risk from CT scans in a group of over 31,000 patients over 22 years was just 0.7% higher than the general population’s 45%. But for those who underwent multiple scans, the risk shot up, ranging from 2.7% to 12%.

Children are particularly vulnerable to the effects of ionizing radiation. A large international study found that people who had at least one CT scan before the age of 22 are at a significantly increased risk for developing blood cancers, specifically including lymphoid and myeloid cancers, as well as acute leukemia. 

Repeated CT scans of the head during childhood have also been linked to a slight increase in the risk of developing a brain tumor later in life due to radiation exposure.

In a landmark 2009 study, researchers estimated that CT scans were responsible for about 2% of all US cancer cases diagnosed annually. However, NBC notes that the true number is likely greater as the number of scans have increased, though radiologists say dosages of radiation have declined per scan.

New radiation regulations underway

New Medicare regulations are aiming to make CT scans safer — without scaring patients away from potentially life-saving imaging tests.

In January, the Centers for Medicare and Medicaid Services (CMS) implemented new rules requiring providers to report more detailed information on radiation levels emitted by their machines. The guidelines, finalized in the last stretch of the Biden administration, also mandate stricter assessments of CT scan doses, quality and necessity.

The requirements will be phased in over the next three years for hospitals, outpatient centers and doctors nationwide. By 2027, non-compliant providers could face financial penalties.

When the Biden administration announced the changes, a CMS spokesperson told NBC News that excessive radiation exposure is a health risk that can be tackled through better measurement and feedback to healthcare providers.

“No one intentionally harms their patients; they just haven’t been paying attention to radiation dose,” said Smith-Bindman, who worked with CMS to develop research solutions aimed at better measuring and assessing the effects of CT scans.

“The measure defines a clear standard for every type of scan with respect to dose and quality, and CMS provides incentives to reach those goals,” she added. “Clinicians can exceed those targets if they deem it necessary; the measure just provides them a way to gauge their performance.”