Irradiation is the process by which an object is exposed to radiation. An irradiator is a device used to expose an object to radiation, notably gamma radiation, for a variety of purposes.[1] Irradiators may be used for sterilizing medical and pharmaceutical supplies, preserving foodstuffs, alteration of gemstone colors, studying radiation effects, eradicating insects through sterile male release programs, or calibrating thermoluminescent dosimeters (TLDs).[2]
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 infrared, visible light, microwaves from cellular phones or electromagnetic waves emitted by radio and television receivers and power supplies.
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.[6][7]
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.[8]
Pure diamonds, before and after irradiation treatment A Initial (2×2 mm size) B Irradiated by different doses of 2 MeV electrons C Irradiated by different doses and then annealed at 800 °C (1,470 °F)
The irradiation process is widely practiced in jewelry industry[11] and enabled the creation of gemstone colors that do not exist or are extremely rare in nature.[12] However, particularly when done in a nuclear reactor, the processes can make gemstones radioactive. Health risks related to the residual radioactivity of the treated gemstones have led to government regulations in many countries.[12][13]
Irradiation is used to cross-linkplastics. 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.
Gheorghe Gheorghiu-Dej, who died of lung cancer in Bucharest on March 19, 1965, may have been intentionally irradiated during a visit to Moscow, due to his political stance.[18]
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.[19][20]
Alexander Litvinenko, a secret serviceman who was tackling organized crime in Russia, was intentionally poisoned with polonium-210; the very large internal doses of radiation he received caused his death.
During the 2001 anthrax attacks, the US Postal Serviceirradiated 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."[citation needed]
^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.
^F. Pene, E. Courtine, A. Cariou, J.P. Mira. Toward theranostics. Crit Care Med, 37 (2009), pp. S50–S58
