Radiation, or often called radioactive, exists in all matter, this is the objective facts existing in the millions, is a normal phenomenon. Radiation is the nucleus from a structure or a state of energy into another kind of structure or in a state of energy is released in the course of microscopic particles. Radiation can make the material cause ionization or excitation, so called ionizing radiation. Ionizing radiation, direct ionization radiation and indirect ionization radiation. Direct ionization radiation charged particles such as protons. Indirect ionization radiation such as photons, neutron not charged particles.