Medical procedures make up 96 percent of the average person’s exposure to man-made radiation, people should limit the number and types of x-rays they receive.

A chest X-ray typically delivers a dose of about 0,1 mSV, while a full-body CT scan packs a 10 mSV punch. By comparison, a CT scan of the chest delivers 7 mSv, while a scan of the head gives 2 mSv. A dental x-ray gives 0,015 mSv, and an x-ray of a hand or foot delivers 0.005 mSv.

All plants and animals contain trace amounts of radioactive potassium-40 and radium-226. However, these amounts are very small.

But some fruits, berries, and mushrooms contain elevated levels of radioactive materials, for example brazil nut – the world’s most radioactive food due to high radium concentrations 1000-times that of average foods.

Radon, a naturally occurring radioactive gas, can become trapped inside walls and basements, elevating long-term cancer risks.