Computed Tomography (CT) scans have become a cornerstone in modern diagnostics, offering detailed images that aid in the detection and management of various medical conditions.However, recent studies suggest that the radiation exposure from these scans may contribute to a significant number of cancer cases annually in the United States.In 2023, approximately 93 million CT scans were performed in the U.S., involving around 62 million patients. A study published in JAMA Internal Medicine estimates that these scans could lead to about 103,000 future cancer diagnoses, accounting for nearly 5% of all new cancer cases in the country. “CT is frequently lifesaving, yet its potential harms are often overlooked, and even very small cancer risks will lead to a significant number of future cancers given the tremendous volume of CT use in the United States,” the researchers have said. The study found that lung cancer was projected to be the most common radiation-induced cancer, with 22,400 cases.Colon cancer was the next most common, with 8700 cases.The risk is particularly pronounced in children and infants due to their developing tissues and longer life expectancy, which increases the window for potential radiation-induced malignancies to develop. Common projected cancers include lung, colon, leukemia, and bladder in adults, and thyroid, lung, and breast cancers in children.
Radiation exposure: How much is too much?
There’s no magic number when it comes to CT scans—but here’s the deal: each scan exposes your body to a dose of ionizing radiation, and over time, those doses add up. While a single CT scan isn’t likely to harm you, repeated scans—especially within a short time—can increase your long-term cancer risk. Radiation dose from CT scans is measured in millisieverts (mSv). For context, the average person in the U.S. receives about 3 mSv per year from natural background radiation.Repeated exposure can accumulate, increasing the risk of radiation-induced cancer.Studies suggest that up to 30% of scans might not even be medically essential. And that’s not great news considering just one chest CT can give you the same radiation as about 100 chest X-rays. So, if you’re getting several scans a year, it’s worth asking your doctor if a lower-radiation alternative could work.
What should you do instead?
If your doctor recommends a CT or nuclear scan, don’t panic—these tests often do more good than harm. But it’s still worth asking how the scan will change your treatment plan. Will it prevent a more invasive test? If not, maybe there’s a better option.Also, try to keep a rough log of your past x-rays or scans. It doesn’t have to be perfect, but it helps you and your doctor gauge how much radiation you’ve been exposed to over time.Always ask if there’s a safer alternative. MRIs and ultrasounds don’t use radiation at all and could work just as well in some cases.Getting regular scans? See if you can space them out more. Fewer scans may still give your doctor the info they need, especially if your condition is stable.Lastly, avoid scans just for peace of mind. CTs rarely find issues in people who don’t have symptoms—and they can sometimes reveal things that lead to more unnecessary radiation.Bottom line? CT scans are lifesaving tools—but use them wisely, ask questions, and make sure each one actually serves a purpose in your care.