ionizing radiation injury

ionizing radiation injury
also called  radiation sickness  

       tissue destruction or changes caused by deeply penetrating electromagnetic waves of high frequency or subatomic particles (subatomic particle) that form positively and negatively charged particles in the tissues, including individual cells (cell) that receive the radiation. Sources for radiation may be natural, such as the elements radium, thorium, and actinium, or radiation may be liberated from such energy-producing devices or substances as X-ray machines, particle accelerators (particle accelerator), nuclear reactors (nuclear reactor), atomic bombs (atomic bomb), and human-made isotopes (isotope). Ionizing radiation injury can affect the whole body system or be localized in one small area. Although the lasting effects of nuclear weapons (nuclear weapon) used in war have been responsible for tens of thousands of deaths due to radiation injury, today nearly all radiation cases result from medical or industrial accidents and overexposures. Acute radiation sickness occurs after high-dose exposures of large areas of the body, whereas chronic effects may persist over a number of years. Damage done to tissue by radiation is not unique—the same types of injuries may be caused by electrical currents and by some drugs (drug) and toxins (toxin)—but the effects of radiation are usually far more devastating and longer lasting.

      The main structures affected by radiation are cells. Radiation energy is not spread diffusely throughout the tissue; rather, the energy rays penetrate into localized areas of tissue, affecting only the cells contacted by the rays. Whether a cell dies immediately or develops molecular changes depends upon the dose of radiation and the length of exposure. Molecular changes in a cell are reflected in its ability to grow and divide to form a normal generation of daughter cells. When the radiation dose is high, cell death is rapid and extensive; there is usually no reserve tissue left to replace that destroyed. If the cell changes are more subtle, the cell may be unable to reproduce altogether or the new cells produced may be abnormal and not viable. The tissues most affected by radiation are those that undergo rapid replacement, such as bone marrow, the lining of the gastrointestinal tract, and skin. Slower-growing tissues, such as those of the brain and liver, require either high doses of radiation or prolonged exposure before they show symptoms of degeneration. The overall direct complications of radiation are cell depletion, inability to reproduce new tissue, lessened body resistance to infections, decreased numbers of blood cells, hemorrhages from disrupted blood vessels (blood vessel), body poisons from tissue breakdown, and a slower blood-clotting time. Indirect effects can be tumour growths, leukemia, a shortened life span, recurrent bacterial infections, anemia, and body ulcers (ulcer).

      Local tissue injuries from radiation may manifest a number of months after the initial exposure or several years after a sequence of exposures. The skin may ulcerate, scale, swell, and slowly deteriorate. Systemic symptoms appear only after the whole body or numerous parts of it have been exposed. Radiation sickness with systemic symptoms can exhibit four stages in milder cases or cause immediate convulsions (convulsion), high blood pressure (hypertension), shock, fever, skin reddening, and death. The first phase in the slower form develops within a few minutes or hours after exposure; symptoms are nausea, vomiting, weakness, and diarrhea. A day or two after exposure, the symptoms depart, and there is a second phase of apparent recovery that may last a week or longer. Third-stage symptoms are fever, infection, vomiting, bloody diarrhea, hemorrhages, dehydration, weight loss, hair loss, and ulcers. Death usually occurs in this phase if the damage has been sufficiently severe. If the patient survives the third phase, the fourth phase (slow recovery) begins about six weeks after the exposure. The recovery may take several months, and there may be permanent disability, such as sterilization, extensive scar tissue, cataracts (cataract), bone disintegration, cancer, and blindness.

* * *

Universalium. 2010.

Игры ⚽ Поможем сделать НИР

Look at other dictionaries:

  • radiation injury — Tissue damage caused by exposure to ionizing radiation. Structures with rapid cell turnover (e.g., skin, stomach or intestinal lining, and bone marrow) are most susceptible. High dose irradiation of the last two causes radiation sickness. Nausea… …   Universalium

  • Non-ionizing radiation — Different types of electromagnetic radiation Non ionizing (or non ionising) radiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum to ionize atoms or molecules that is, to completely remove an… …   Wikipedia

  • radiation — radiational, adj. /ray dee ay sheuhn/, n. 1. Physics. a. the process in which energy is emitted as particles or waves. b. the complete process in which energy is emitted by one body, transmitted through an intervening medium or space, and… …   Universalium

  • radiation therapy — radiotherapy. * * * or radiotherapy or therapeutic radiology Use of radiation sources to treat or relieve diseases, usually cancer (including leukemia). The ionizing radiation primarily used to destroy diseased cells works best on fast growing… …   Universalium

  • Radiation burn — Classification and external resources ICD 9 990 …   Wikipedia

  • Radiation therapy — Radiation (medicine) redirects here. It is not to be confused with Radiation (pain) or Radiology. Radiation therapy Intervention ICD 10 PCS D ICD 9 CM …   Wikipedia

  • Radiation poisoning — Radiation poisoning, also called radiation sickness or a creeping dose , is a form of damage to organ tissue due to excessive exposure to ionizing radiation. The term is generally used to refer to acute problems caused by a large dosage of… …   Wikipedia

  • Radiation induced cognitive decline — Radiation Induced Cognitive DeclineRadiation therapy is used mainly in the treatment of cancer. Usually it is recommended to apply radiation to cancerous tumors in areas that are difficult for chemotherapy to reach. Thus radiation therapy has… …   Wikipedia

  • Radiation dose reconstruction — refers to the process of estimating radiation doses that were received by individuals or populations in the past as a result of particular exposure situations of concern.[1] The basic principle of radiation dose reconstruction is to characterize… …   Wikipedia

  • Acute radiation syndrome — Classification and external resources A Japanese girl recovering from the effects of radiation sickness ICD 10 T …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”