You can't avoid radiation that occurs naturally. But there are some things you can do to reduce your exposure to man-made sources.
If you are concerned about the risk of getting cancer from having a CT scan, talk to your doctor about the amount of radiation this test may give you. Confirm that the test is needed. Ask whether another test, such as an ultrasound or an MRI, can be done instead. In some cases, the benefits of having a CT scan outweigh the small risk of getting cancer.
If you have concerns about radiation exposure from a full-body airport scanner, ask if you can get a pat-down instead. (But the amount of radiation exposure from one of these scanners is very low.)
If you are exposed to radiation from a nuclear accident:
Wait for instructions from public health and emergency officials to tell you what to do. Depending on the kind of accident, authorities may advise you to shelter in place or simply to stay indoors. You don't need to leave your community unless local authorities tell you to.
Don't take potassium iodide (KI) tablets unless local authorities tell you to and your doctor says that it's okay. These tablets help protect your thyroid gland from the harmful effects of radioactive iodine, which can be released as a result of a nuclear accident. They don't protect against any other radioactive substances. KI tablets can be harmful if you don't take them properly, are allergic to iodine, or have certain skin or other health problems. Some common side effects include upset stomach, skin rash, swollen salivary glands, and a metallic taste in your mouth. In rare cases, a person may have a severe allergic reaction. The reaction may cause breathing problems, hives, or swelling around the lips, tongue, or face.