Most of us think that we understand the heat that we feel, the light that we see, and even chemicals, if we can smell them. But, for most people, imperceptible ionizing electromagnetic radiation, x-rays and gamma rays, and fast charged particles are a mystery. Most people know that these entities, loosely described as "radiation," can cause great havoc to tissue, but do not seem to know that they have always been with us in some measure, and that a careful, selective use of them is highly beneficial. Only a limited number of people have the experience and capability to understand how much is good and how much excessive. Nevertheless, many more want to participate in decisions involving radiation.
The fact that an atom is radioactive and emits ionizing radiation is not necessarily bad. These atoms can be dangerous in large quanitity, yet safe and useful in small quantity.