Every year, millions of Americans lie down on a narrow table, slide through a donut-shaped machine, and hold their breath for a few seconds. The CT scan is quick, painless, and often lifesaving. But a bombshell 2025 study is raising a question no one in medicine wants to answer: are we doing too many of them?
What Is a CT Scan — And Why Are Doctors Ordering More Than Ever?
A CT scan — short for computed tomography — uses a rotating series of X-rays and a computer algorithm to build detailed, cross-sectional images of the body’s interior. It can detect diseases and injuries, producing detailed pictures of bones, soft tissues, blood vessels, and organs Cleveland Clinic that a standard X-ray simply cannot capture. It is fast, widely available, and extraordinarily versatile.
CT scans are routinely used to find cancer, bone fractures, internal bleeding, blood clots, and injuries to the spine and brain. WebMD In emergencies, they’re the difference between life and death. For a patient arriving at the ER after a car accident or showing signs of a stroke, a CT scan delivers answers in minutes.
But there’s a catch. And it’s a big one.
A Surge No One Planned For
The number of CT examinations performed each year in the U.S. has increased by more than 30 percent since 2007, and researchers suggest that unwarranted tests are exposing the population to unnecessary radiation. Science Alert
About 93 million CT scans are performed every year in the United States, with more than half for people 60 and older. KFF Health News That’s nearly one scan for every three Americans — annually.
And ER departments are driving a significant portion of that surge. Use of head CT scans in U.S. emergency departments has more than doubled over the past 15 years. Nearly 16 million head CT scans were ordered by ERs in 2022, up from under 8 million in 2007. Powers Health
Here’s What We Know
The science is clear on the fundamentals: CT scans use ionizing radiation, and ionizing radiation carries risk. The widespread use of CT and other procedures that use ionizing radiation to create images of the body has raised concerns that even small increases in cancer risk could lead to large numbers of future cancers. National Cancer Institute
For any one patient, the individual risk is small. But multiply that small risk across 93 million scans per year, and the numbers start to look alarming.
A new study estimates that 103,000 cancer diagnoses — or 5% of all cancers — could result from the 93 million scans performed in the U.S. in 2023 alone. NPR
Almost 10,000 of those projected cancer cases involve children. ecancer
“It’s Unfathomable”
The radiation problem isn’t just about volume — it’s about consistency. Or rather, the startling lack of it.
One CT scan can expose a patient to 10 or 15 times as much radiation as another for the same clinical problem. The variation isn’t 10% different — it’s tenfold. KFF Health News And there are currently no federal standards regulating radiation dosages.
Lead researcher Dr. Rebecca Smith-Bindman of UC San Francisco has been pushing for change for years. “There’s nothing you can do about radiation that you’ve been exposed to already. But you want to limit future exposure to cases when you really need it,” she said. Some scans, she notes, add no diagnostic value at all. NPR
So far, one-third of scans exceed the targets in their quality testing. NPR
Why Doctors Keep Ordering Them Anyway
Doctors in the United Kingdom prescribe about 7 times fewer CT scans than those in the United States. French doctors prescribe 3 times fewer. In Germany, about half as many. PubMed Central Why does America stand apart? Researchers point to economic incentives and what experts call “defensive medicine” — ordering tests to cover legal liability rather than clinical necessity.
Educational research shows that the roots of overuse begin in training. A study simulating medical students’ first day of residency found that nearly 70% of cases involved unnecessary abdominal CT scans or chest X-rays. U.S. News & World Report Overordering isn’t a habit developed in practice. It’s baked in from day one.
“Head CT scans are a critical tool for diagnosing neurological emergencies, but their growing use raises concerns about cost, radiation exposure, and delays in the emergency department,” said Dr. Layne Dylla of Yale School of Medicine. Powers Health
The Scans That Save Lives — and the Ones That Don’t
None of this means CT scans are bad. Far from it. CT scans can diagnose possibly life-threatening conditions such as hemorrhage, blood clots, or cancer — an early diagnosis of these conditions could potentially be lifesaving. National Institute of Biomedical Imaging and Bioengineering The technology is also advancing rapidly. Photon-counting CT scanners, now entering widespread clinical use, offer improved resolution while delivering lower radiation doses and requiring less contrast agent Cassling — a meaningful step forward.
The real issue is the gap between the scans that are genuinely necessary and the millions that aren’t.
“We need patients to ask their doctors, ‘Can you use low dose when you scan me?'” Smith-Bindman said. NPR
What You Can Do Right Now
The FDA and leading medical organizations agree: if your doctor recommends a CT scan, discuss it. Ask whether it’s clinically necessary. Ask whether a radiation-free alternative — like an MRI or ultrasound — could provide the same answers.
The FDA does not see a benefit to whole-body scanning of individuals without symptoms FDA — a category of elective “wellness” scanning that has been quietly growing.
The CT scan remains one of medicine’s most powerful tools. The question the medical community is now being forced to confront is this: powerful in whose hands, and when?
A machine designed to find cancer, used carelessly, may be quietly creating it.