Radiation is an inescapable part of everyday life. Everyone receives an annual radiation dose from sources that include the sun and naturally occurring radioactive material in the earth and in certain foods. The dose you receive annually from these background sources varies with soil and rock content, elevation of your city, and your diet. In addition to these naturally occurring sources of radiation, exposure can come from x-rays and cat-scans, cigarettes, televisions, mobile phones, radiation-based medical tests and treatments, and manufacturing and industrial uses of radiation.