Irradiation

This article is about the physics of irradiation. For the visual illusion, see irradiation illusion.

Irradiation is the process by which an object is exposed to radiation. The exposure can originate from various sources, including natural sources. Most frequently the term refers to ionizing radiation, and to a level of radiation that will serve a specific purpose, rather than radiation exposure to normal levels of background radiation. The term irradiation usually excludes the exposure to non-ionizing radiation, such as infra-red, visible light, microwaves from cellular phones or electromagnetic waves emitted by radio and TV receivers and power supplies.

Applications

Sterilization

If administered at appropriate levels, all forms of ionizing radiation can be used to sterilize objects after use, produce medical instruments and disposables such as syringes, and disinfect and sterilize food. Small doses of ionizing radiation (electron beam processing, X-rays and gamma rays)[1] may be used to kill bacteria in food or other organic material, including blood. Food irradiation, while effective, is seldom used due to problems with public acceptance.[2]

Medicine

Irradiation is used in diagnostic imaging, cancer therapy and blood transfusion.[3]

In 2011 researchers found that irradiation was successful in the novel theranostic technique involving co-treatment with heptamethine dyes to elucidate tumor cells and attenuate their growth with minimal side effects.[4][5]

Ion implantation

Main article: Ion implantation

Ion irradiation is routinely used to implant impurities atoms into materials, especially semiconductors, to modify their properties. This process, usually known as ion implantation, is an important step in the manufacture of silicon integrated circuits.

Ion irradiation

Ion irradiation means in general using particle accelerators to shoot energetic ions on a material. Ion implantation is a variety of ion irradiation, as is swift heavy ions irradiation from particle accelerators induces ion tracks that can be used for nanotechnology.

Industrial chemistry

Irradiation can be used to cross-link plastics or to improve material qualities of semi-precious stones. Due to its efficiency, electron beam processing is often used in the irradiation treatment of polymer-based products to improve their mechanical, thermal, and chemical properties, and often to add unique properties. Cross-linked polyethylene pipe (PEX), high-temperature products such as tubing and gaskets, wire and cable jacket curing, curing of composite materials, and crosslinking of tires are a few examples.

Security

During the 2001 anthrax attacks, the US Postal Service irradiated mail to protect members of the US government and other possible targets. This was of some concern to people who send digital media through the mail, including artists. According to the ART in Embassies program, "incoming mail is irradiated, and the process destroys slides, transparencies and disks."

Agriculture

Main article: Mutation breeding

After its discovery by Lewis Stadler at the University of Missouri, irradiation of seed and plant germplasm has resulted in creating many of the most widely grown strains of food crops worldwide. The process, which consists of striking plant seeds or germplasm with radiation in the form of X-rays, UV waves, heavy-ion beams, or gamma rays, essentially "mixes" the genes already existing in the genome. The UN has been an active participant through the International Atomic Energy Agency. Irradiation is also employed to prevent the sprouting of certain cereals, onions, potatoes and garlic.[6] Appropriate irradiation doses are also used to produce insects for use in the sterile insect technique of pest control.[7]

Main article: Food irradiation

The U.S. Department of Agriculture's (USDA) Food Safety and Inspection Service (FSIS) recognizes irradiation as an important technology to protect consumers. Fresh meat and poultry including whole or cut up birds, skinless poultry, pork chops, roasts, stew meat, liver, hamburgers, ground meat, and ground poultry are approved for irradiation.[8]

Assassination

Some claim that Gheorghe Gheorghiu-Dej, who died of lung cancer in Bucharest on March 19, 1965, was intentionally irradiated during a visit to Moscow, due to his political stance.[9]

In 1999, an article in Der Spiegel alleged that the East German MfS intentionally irradiated political prisoners with high-dose radiation, possibly to provoke cancer.[10][11]

Alexander Litvinenko, a secret serviceman who was tackling organized crime in Russia, was intentionally poisoned with Po-210; the very large internal doses of radiation he received was the cause of his death.

References

  1. ↑ "Food Standards Agency - Irradiated food". Retrieved 2008-01-26.
  2. ↑ "Spinach and Peanuts, With a Dash of Radiation" article by Andrew Marin in The New York Times February 1, 2009
  3. ↑ "Information for patients needing irradiated blood" by National Blood Service
  4. ↑ Tan X, Luo S, Wang D, et al. A NIR heptamethine Dye with intrinsic cancer targeting, imaging and photosynthesizing properties. Journal of Biomaterials China. 33-7 (2011), pp. 2230-2239.
  5. ↑ F. Pene, E. Courtine, A. Cariou, J.P. Mira. Toward theranostics. Crit Care Med, 37 (2009), pp. S50–S58
  6. ↑ Bly, J.H. "Electron Beam Processing", Yardley, PA: International Information Associates, 1988.
  7. ↑ International Database on Insect Disinfestation and Sterilization, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture website, Food and Agriculture Organization of the United Nations, plus the International Atomic Energy Agency.
  8. ↑ Irradiation and Food Safety, U.S. Drug and Food Administration. Retrieved Jan. 5, 2010.
  9. ↑ "TFP > Alexander Litvinenko Assassination". Retrieved 2009-10-18.
  10. ↑ STASI: In Kopfhöhe ausgerichtet. Article by Peter Wensierski in Der Spiegel 20/1999, May 17, 1999
  11. ↑ Tödliche Strahlung. Die Staatssicherheit der DDR steht im Verdacht, Regimegegner radioaktiv verseucht zu haben. Article by Paul Leonhard in Junge Freiheit April 14, 2000

External links

See also

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