radiation exposure

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radiation exposure

a measure of the ionization produced in air by x-rays or gamma rays. It is the sum of the electric charges on all ions of one sign that are produced when all electrons liberated by the radiation in a volume of air are completely stopped, divided by the mass of air in that volume. The unit of exposure is the roentgen. Acute radiation exposure is exposure of short duration to intense ionizing radiation, usually occurring as the result of an accidental spill of radioactive material. Exposure of the whole body to approximately 10,000 rad (100 gray) causes neurological and cardiovascular breakdown and is fatal within 24 hours. A dose between 500 and 1200 rad (5 and 12 gray) destroys GI mucosa, produces bloody diarrhea, and may cause death in several days. A dose of 200 to 500 rad (2 to 5 gray) destroys the blood-forming organs and may cause death in a few weeks.

radiation exposure, emergency procedures

first-aid treatment of a person who has received external body radiation through exposure to radioactive material or internal radiation contamination by inhaling or ingesting radioactive material. External radiation exposure is treated initially by cleansing and surgical isolation to protect others. One who has inhaled or ingested radioactive material should be given emergency treatment similar to a person who has been exposed to chemical poisons. Body wastes should be collected and checked for radiation levels. If the victim has also suffered a wound, care must be taken to avoid cross-contamination of exposed surfaces. In general, except for taking special precautions to control the spread of radiation effects, the patient should be given any lifesaving emergency treatment needed, and personnel handling the patient should wear surgical gowns, caps, and gloves. Also called emergency handling of radiation accidents.


1. divergence from a common center.
2. a structure made up of diverging elements, especially a tract of the central nervous system made up of diverging fibers.
3. energy carried by waves or a stream of particles. One type is electromagnetic radiation, which consists of wave motion of electric and magnetic fields. The quantum theory is based on the fact that electromagnetic waves consist of discrete particles, called photons, that have an energy inversely proportional to the wavelength of the wave. In order of increasing photon energy and decreasing wavelength, the electromagnetic spectrum is divided into radio waves, infrared light, visible light, ultraviolet light and x-rays.
Another type is the radiation emitted by radioactive materials. Alpha particles are high-energy helium-4 nuclei consisting of two protons and two neutrons, which are emitted by radioisotopes of heavy elements, such as uranium. Beta particles are high-energy electrons, which are emitted by radioisotopes of lighter elements. Gamma rays are high-energy photons, which are emitted along with alpha and beta particles and are also emitted alone by metastable radionuclides, such as technetium-99m. Gamma rays have energies in the x-ray region of the spectrum and differ from x-rays only in that they are produced by radioactive decay rather than by x-ray machines.
Radiation with enough energy to knock electrons out of atoms and produce ions is called ionizing radiation. This includes alpha and beta particles and x-rays and gamma rays.

radiation biology
study of the effects of ionizing radiation on living tissues.
corpuscular radiation
particles emitted in nuclear disintegration, including alpha and beta particles, protons, neutrons, positrons and deuterons.
radiation detection
special equipment, including Geiger-Müller tubes and a scintillation crystal, is available to detect radiation which may be accidental, or detect small amounts where this is expected but it needs to be measured in terms of accumulated dose.
electromagnetic radiation
energy, unassociated with matter, that is transmitted through space by means of waves (electromagnetic waves) traveling in all instances at 3 × 1010 cm or 186,284 miles per second, but ranging in length from 1011 cm (electrical waves) to 10−12 cm (cosmic rays) and including radio waves, infrared, visible light and ultraviolet, x-rays and gamma rays.
radiation exposure
means more than the patient being exposed intentionally to an x-ray beam. Technical persons in the vicinity will also be exposed to a much less dangerous but perniciously cumulative load of radiation.
infrared radiation
the portion of the spectrum of electromagnetic radiation of wavelengths ranging between 0.75 and 1000 μm. See also infrared.
radiation injury
is caused by exposure to radioactive material. High doses cause intense diarrhea and dehydration and extensive skin necrosis. Median doses cause initial anorexia, lethargy and vomiting then normality for several weeks followed by vomiting, nasal discharge, dysentery, recumbency, septicemia and a profound pancytopenia. Death is the most common outcome. Chronic doses cause cataract in a few. Congenital defects occur rarely.
interstitial radiation
energy emitted by radium or radon inserted directly into the tissue.
ionizing radiation
corpuscular or electromagnetic radiation that is capable of producing ions, directly or indirectly, in its passage through matter. Used in treatment of radiosensitive cancer, in sterilization of animal products and food for experimental use.
radiation necrosis
see radionecrosis.
radiation physicist
the person responsible for the administration of radiation therapy including estimating the dose required for a treatment, arranging for the dose to be delivered and making arrangements for safety of the patient and staff, and disposing of any residual radioactive material. Technical aspects of the work include computer estimations, preparation of isodose curves, preparation of wedge and compensating filters, and calibration of teletherapy equipment.
primary radiation
radiation emanating from the x-ray tube which is absorbed by the subject or passes on through the subject without any change in photon energy.
radiation protection
includes proper control of emissions from the x-ray machines, proper protective clothing for staff, keeping unnecessary people out of the way while the tube is actually generating its beam, the wearing and regular examination of a dosimeter and the proper storage of radioactive materials or residues.
pyramidal radiation
fibers extending from the pyramidal tract to the cortex.
radiation sensitivity
tissues vary in their sensitivity to the damaging effects of irradiation. The rapidly growing tissues are most susceptible, e.g. the embryo, rapidly growing cancer, gonads, alimentary tract, skin and blood-forming organs.
radiation sickness
see radiation injury (above).
solar radiation
see solar.
radiation striothalamica
a fiber system joining the thalamus and the hypothalamic region.
tegmental radiation
fibers radiating laterally from the nucleus ruber.
thalamic radiation
fibers streaming out through the lateral surface of the thalamus, through the internal capsule to the cerebral cortex.
radiation therapist
a person skilled in radiotherapy. See also radiation therapy (below).
radiation therapy
ultraviolet radiation
the portion of the spectrum of electromagnetic radiation of wavelengths ranging between 0.39 and 0.18 μm. See also ultraviolet rays.
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Emergency procedures will be enforced by the BDF, Public Security and the National Guard, in addition to other forces if needed.
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An airport spokesman said: "As a precautionary measure, emergency procedures were enacted after a plane from Southampton, carrying only four crew reported technical difficulties.

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