CT scans have become a cornerstone of modern medicine—fast, detailed, and widely available. They help doctors spot internal injuries, diagnose diseases, and make treatment decisions that can save lives. But a new study suggests we may be paying a hidden price for this convenience. According to research published in JAMA Internal Medicine, CT scans performed in the U.S. in just one year—2023—could eventually lead to over 100,000 cases of cancer, with nearly 10,000 in children alone.
The issue isn’t the scans themselves. It’s how often and how indiscriminately they’re used. Despite growing awareness of the risks tied to ionizing radiation, the number of CT scans continues to rise, driven by everything from defensive medicine to direct-to-consumer marketing. And while each individual scan may carry only a small risk, those risks add up across a population—especially when scans are done without clear medical necessity.
CT Scans and Cancer Risk—What the Latest Research Actually Says
A new study published in JAMA Internal Medicine has raised concerns about the widespread use of CT (computed tomography) scans in the United States. According to researchers from institutions including the Institute of Cancer Research (London), Kaiser Permanente Washington, and UCSF, the overuse of CT scans could be linked to over 100,000 future cases of cancer in the U.S.—nearly 10,000 of which could occur in children. This represents around 5% of all cancers in the country, comparable to the proportion linked to alcohol consumption.
CT scans are undeniably valuable in diagnosing serious health issues such as internal injuries, cancers, and vascular diseases. But they rely on ionizing radiation, which is known to increase cancer risk. While the risk for any one person is relatively small, the collective impact becomes significant when millions of people undergo these scans—particularly when some of them might not be necessary.
The number of CT scans in the U.S. has increased by 30% since 2009, reaching 93 million scans in 2023 alone. Of these, approximately 2.5 million were performed on children. Using established risk models that factor in dose and age sensitivity, researchers estimate that these scans will lead to about 9,700 future cancers in children. For adults, most radiation-linked cancers are expected to stem from chest and abdominal CTs, while in children, brain CTs are the primary concern due to higher radiation sensitivity in developing tissues.
Experts stress that the individual benefit of a CT scan—when used appropriately—still outweighs the risk. But this assumes that the scan is medically justified and that radiation doses are optimized for the patient’s age and body part. As Professor Amy Berrington of the Institute of Cancer Research notes, “small risks do add up” across a population, especially when scans are performed routinely or unnecessarily.
Why CT Scan Use Has Skyrocketed—and Why That’s a Problem
The sheer volume of CT scans in the U.S.—93 million in 2023—is not a coincidence. Several factors have driven this surge, including greater access to advanced imaging, increasing patient demand for quick answers, and a defensive medicine mindset among healthcare providers. Doctors may order scans to rule out worst-case scenarios or avoid potential legal liability, even in cases where clinical guidelines don’t warrant it. Add to this the influence of direct-to-consumer marketing for “preventive” full-body scans, and the result is a system that increasingly relies on high-dose imaging as a routine measure, not a carefully weighed decision.
This growth in CT use matters because the radiation involved is not trivial. A single CT scan can deliver 100 to 500 times more radiation than a standard X-ray. When scans are repeated, or when high doses are used without proper dose adjustments for age and body part, cumulative exposure becomes a serious issue. Children, in particular, are more vulnerable because their cells are dividing more rapidly and they have more years ahead for radiation-induced cancers to develop. Yet the study found that even adults are at significant risk, especially from frequent chest and abdominal scans.
There’s also wide variability in radiation doses across hospitals, even within the same healthcare system. According to Dr. Rebecca Smith-Bindman, a radiologist and epidemiologist at UCSF, this inconsistency represents a missed opportunity. “The doses for CT remain highly variable… and there are opportunities to reduce those doses without reducing the accuracy of the tests,” she said. This means that many patients may be getting more radiation than is necessary for a diagnostic-quality image.
Compounding the problem is a lack of standardized oversight, especially in the U.S., where regulation is less centralized than in countries like the UK. In Britain, radiologists are required to review and approve CT requests to ensure they are clinically justified. The UK also has lower population-level scanning rates—less than 100 CT scans per 1,000 people compared to over 250 per 1,000 in the U.S.—and this oversight has helped keep unnecessary exposure in check.
Unchecked CT scan use is a systemic issue, not just a clinical one. It reflects how healthcare systems balance access, regulation, and profit. Without stronger protocols for when and how CT scans are used, the risks tied to ionizing radiation will continue to rise alongside the scan rates.
The Science Behind CT Radiation and Cancer Risk
Understanding the risk of cancer from CT scans starts with how these scans work. CT imaging uses ionizing radiation—specifically X-rays—to create detailed cross-sectional images of the body. Unlike ultrasound or MRI, which use sound waves or magnetic fields, CT exposes the body to radiation that can damage DNA. If the damage isn’t properly repaired by the body, it can lead to mutations that increase the likelihood of cancer over time.
The amount of radiation from a single CT scan is relatively high. For example, a chest CT can deliver a dose of around 7 millisieverts (mSv), compared to just 0.1 mSv for a chest X-ray. The cumulative risk rises with repeated scans, especially when conducted over short periods. The body doesn’t “reset” its radiation exposure—every dose adds to the total, and every added scan increases the statistical risk of developing cancer.
What the recent study made clear is that this isn’t just theoretical. By applying a validated public health risk model developed by Professor Amy Berrington at the Institute of Cancer Research, researchers were able to estimate the number and types of cancers likely to result from the CT scans performed in 2023. These aren’t speculative numbers—they’re based on existing epidemiological data and reflect real-world exposure levels.
Importantly, the model takes into account differences in organ sensitivity and age. Children’s brains, for example, are particularly sensitive to radiation, which is why brain CTs in pediatric populations carry a higher risk. In adults, the most common risks are tied to chest and abdominal imaging, where vital organs like the lungs, liver, and gastrointestinal tract are more susceptible to radiation effects.
The researchers aren’t suggesting that CT scans be avoided across the board. Instead, they emphasize the importance of using them only when medically necessary and adjusting radiation doses based on patient characteristics. Doing so not only reduces the individual’s risk but also lowers the public health burden over time. As Professor Berrington put it, “for the individual patient, this increased risk is small… but when millions of CT scans are being carried out across the population, these small risks do add up.”
This body of research doesn’t challenge the value of CT scans—it challenges the assumption that more imaging automatically leads to better care. It’s a call to rethink how and when this powerful diagnostic tool is used, especially given its long-term health consequences.
Tips for Minimizing CT Scan Risks
CT scans are essential for diagnosing serious health conditions, but they come with the risk of radiation exposure. To ensure you’re getting the benefits of CT scans without unnecessarily increasing your cancer risk, here are some practical tips to keep in mind.
- Confirm the necessity: Always ask your doctor if a CT scan is truly necessary for your condition. In some cases, other imaging methods, like MRIs or ultrasounds, might offer similar diagnostic value without the radiation risk.
- Understand the radiation risks: Be sure to discuss the long-term implications of multiple scans, especially for conditions that don’t require urgent diagnosis.
- Limit repeat scans: If you’ve already had a recent CT scan, check with your healthcare provider if another one is needed, or if your previous scans provide sufficient information. Repeated scans, especially in a short time, can significantly increase your exposure.
- Choose facilities with safety protocols: Some hospitals and imaging centers take extra steps to minimize radiation exposure by using lower doses or adjusting the technique based on the patient’s age and body size. Ask if your chosen facility follows these protocols to ensure safety, particularly for children.
- Ask about radiation dose adjustments: For certain scans, such as chest or abdominal CTs, radiation doses can be reduced without compromising image quality. Don’t hesitate to ask your doctor or radiologist if this is possible in your case.
- Advocate for a second opinion: If a CT scan is recommended for a non-emergency situation, consider seeking a second opinion to ensure that it’s truly necessary and that other options have been explored.
Being proactive and asking the right questions can help minimize unnecessary radiation exposure while ensuring that CT scans are used only when truly needed. This approach can help protect your long-term health while still benefiting from the diagnostic power of CT imaging.
Scan Smarter, Not More
CT scans save lives. They detect cancers early, uncover internal injuries, and guide treatment in critical ways. But like any medical tool, they come with trade-offs—and the latest data makes one thing clear: overuse has a cost. If the U.S. continues its current rate of scanning, CT-related cancers could make up 5% of all future cases. That’s not a small number, and it’s not inevitable.
The key takeaway isn’t fear—it’s responsibility. Every CT scan should be treated with the same level of scrutiny as prescribing a powerful medication. Just as we wouldn’t prescribe antibiotics for a viral cold, we shouldn’t rely on high-radiation imaging when safer, equally effective options are available—or when no imaging is needed at all.
The call to action is straightforward: scan smarter. Advocate for informed decisions, challenge routine habits, and push for safety standards that put patient health first—not just in the moment, but long term. That’s how we protect lives—both now and in the decades to come.
Source:
- Smith-Bindman R, Chu PW, Azman Firdaus H, et al. Projected Lifetime Cancer Risks From Current Computed Tomography Imaging. JAMA Intern Med. 2025;185(6):710–719. doi:10.1001/jamainternmed.2025.0505
