Most people consider talking on a cell phone, using a microwave or even going through airport scanners safe things to do. But these activities can expose us to a hidden danger to our bodies … radiation … which in some cases could raise the risk of cancer.

Now experts warn we are being overexposed to radiation. And ironically, most of the harmful radiation exposure comes from medical tests that are used to keep you healthy.

More than sixty million people each year have CT scans, or “super X-rays.” A CT scan provides physicians with cross-sectional images or slices of the body, like the slices in a loaf of bread. These slices help doctors diagnose or rule out a disease or condition.

The detailed images can be life-saving but also expose people to higher levels of radiation compared with other traditional medical tests such as ultrasound and magnetic resonance imaging.

CT scans deliver at least one hundred times more radiation than a normal chest X-ray and up to ten times more radiation than we are exposed to in the natural environment every year. Experts say CT tests, when taken individually, are safe. But over time, the radiation exposure can add up to unsafe levels, leading to a higher risk of cancer.

Consumers should play an important role in reducing their radiation risk. Experts suggest asking your doctor about other procedures that still allow a good assessment of your medical situation. Depending on the situation, you might have other options.

But most importantly, they suggest keeping a detailed list of your imaging history. Knowing this information may help limit your exposure to this hidden danger unless it’s absolutely necessary, leading to a lifetime of good health.