Problem statement: Ionizing radiation is all around us, and it has been this way since the creation of the Earth. As such, life on Earth has evolved in an environment exposed to ionizing radiation, and has adapted to be able to thrive in its presence. It comes from space (cosmic radiation), the ground (terrestrial radiation), from air, water, and even food. We are also exposed to human-made sources of ionizing radiation such as medical x-rays and CT (computed tomography) scans. When normal repair processes fail, and when cellular apoptosis does not occur, the DNA may be irreparably damaged. Cells with damaged DNA that survive and reproduce can lead to cancer, and failure to correct damage in cells that form gametes (reproductive cells) can result in mutations being passed on to off spring When cells are exposed to ionizing radiation, damage can occur either by direct action or indirect action.