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Ionizing radiation includes electromagnetic radiation with enough energy to break chemical bonds through nonthermal process (X and gamma photons or “rays”); and high-speed subatomic particles.
Ionizing radiation can be produced by electrical devices such as X-ray machines. Ionizing radiation also can arise from nuclear processes such as radioactivity (alpha, beta, and gamma emissions commonly are associated with radioactivity), nuclear fission and fusion and
from outer space.
Nonionizing radiation is electromagnetic radiation with insufficient energy to break chemical bonds through nonthermal processes. Examples of nonionizing radiation include radio and TV transmissions; microwaves and radar; and infared, visible and ultraviolet lihjt (including
that produced by lasers).
Nonionizing radiation is also known as electromagnetic field. The ancients knew of lodestones, static electricity and lightning. They knew that lightning, the thunderbolt of the gods, could kill or injure. But it was not until the 19 century that scientists began to understand electric and magnetic fields and their extend
in space.
X-rays were discovered in 1895 by Rontgen, radioactivity and its associated radiations in 1896 by Becquerel. Soon afterward the harmful effects of ionizing radiation became known and controversies
about its risk benefits began.
Radioactive atoms undergo spontaneous nucleartransformations and release excess energy in the form of ionizing radiation. The body attempts to repair the damage, but sometimes the damage is too severe or widespread, or mistakes are made in the natural
repair process.
The most common forms of ionizing radiation are alpha and beta particles, or gamma and X-rays.
What kinds of health effects occur from exposure to radionuclides? In general, the amount and duration of radiation exposure affects the severity or type of health effect.
Stochastic Health Effects
Stochastic effects are associated with long-term, low-level (chronic) exposure to radiation. ("Stochastic" refers to the likelihood that something will happen.)
Increased levels of exposure make these health effects more likely to occur, but do not influence the type or severity of the effect.
Radiation can cause changes in DNA, the "blueprints" that ensure cell repair and replacement produces a perfect copy of the original cell. Changes in DNA are called mutations.
Calcium, strontium-90, and radium-226 have similar
chemical properties.
What is the cancer risk from radiation? How does it compare to the risk of cancer from other sources?
What are the risks of other long-term health effects? Other than cancer, the most prominent long-term health effects are teratogenic and genetic mutations.