Radiation hormesis 1106101 224203883 2008-07-07T20:06:39Z Pdbailey 98556 /* Ongoing Debate */ remove POV tag {{merge|Radiation homeostasis|date=March 2008}} '''Radiation hormesis''' is the [[hypothesis]] that chronic low doses of [[ionizing radiation]] stimulates repair mechanisms that protect against [[disease]].<ref name="Calabrese">{{Cite journal | doi = 10.1038/421691a | issn = 0028-0836 | volume = 421 | issue = 6924 | pages = 691–692 | last = Calabrese | first = Edward J | coauthors = Linda A Baldwin | title = Toxicology rethinks its central belief | journal = Nature | accessdate = 2008-04-01 | date = 2003-02-13 | url = http://www.nature.com/nature/journal/v421/n6924/full/421691a.html }}</ref><ref>{{Cite journal | volume = 78 | pages = 3–7 | last = Feinendegen | first = L.E. | title = Evidence for beneficial low level radiation effects and radiation hormesis | journal = British Journal of Radiology | doi = 10.1259/bjr/63353075 | date = 2005 | pmid = 15673519 }} </ref><ref name ="Kaiser"> {{Cite journal | doi = 10.1126/science.302.5644.376 | volume = 302 | issue = 5644 | pages = 376–379 | last = Kaiser | first = Jocelyn | title = HORMESIS: Sipping From a Poisoned Chalice | journal = Science | accessdate = 2008-03-31 | date = 2003-10-17 | url = http://www.sciencemag.org/cgi/content/summary/302/5644/376 | pmid = 14563981 }} </ref><ref> {{Cite journal | volume = 106 | issue = 1 | pages = 277–283 | last = Wolff | first = S. | title = The adaptive response in radiobiology: evolving insights and implications | journal = Environmental Health Perspectives | url = http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=9539019 | date = 1998-02 | doi = 10.2307/3433927 | pmid = 9539019 }} </ref> The Académie des Sciences - Académie nationale de Médecine ([[French Academy of Sciences]] - [[French Academy of Medicine|National Academy of Medicine]]) in their 2005 report concerning the effects of low level radiation, acknowledged that 40% of laboratory studies have observed radiation hormesis.<ref name = "Calabrese2">{{Cite journal | doi = 10.1016/j.taap.2004.02.007 | volume = 197 | issue = 2 | pages = 125–136 | last = Calabrese | first = Edward J. | title = Hormesis: from marginalization to mainstream: A case for hormesis as the default dose-response model in risk assessment | journal = Toxicology and Applied Pharmacology | accessdate = 2008-04-01 | date = 2004-06-01 | url = http://www.sciencedirect.com/science?_ob=MImg&_imagekey=B6WXH-4C1T2FR-3-3&_cdi=7159&_user=10&_orig=search&_coverDate=06%2F01%2F2004&_sk=998029997&view=c&wchp=dGLbVzW-zSkWb&md5=ae4625e58b2c144985bb1f4204f22ca9&ie=/sdarticle.pdf }}</ref><ref name = "Duport">{{Cite journal | doi = 10.1504/IJLR.2003.003488 | volume = 1 | issue = 11 | pages = 120–131 | last = Duport | first = P. | title = A database of cancer induction by low-dose radiation in mammals: overview and initial observations | series = International Journal of Low Radiation | accessdate = 2008-04-01 | date = 2003-09-11 | url = http://www.ie.uottawa.ca/Shared/ADatabaseofCancerInduction.pdf | journal = International Journal of Low Radiation }}</ref> However, they cautioned that it is not yet known if radiation hormesis occurs outside the laboratory, in humans.<ref name="Aurengo">{{Cite paper | author = Aurengo ''et al.'' | title = ''Dose-effect relationships and estimation of the carcinogenic effects of low doses of ionizing radiation.'' | publisher = Académie des Sciences & Académie nationale de Médecine | date = 2005-30-03 | url =http://www.radscihealth.org/rsh/Papers/FrenchAcadsFinal07_04_05.pdf | accessdate = 2008-03-27 }}</ref> Additionally, the other major consensus reports by the [[United States National Research Council]] and the [[National Council on Radiation Protection and Measurements]] and the [[United Nations Scientific Committee on the Effects of Atomic Radiation]] (UNSCEAR) have all upheld the [[Linear_no-threshold_model|Linear no-threshold model]] (LNT) (that radiation is dangerous no mater how low the exposure) and discounted the existence of radiation hormesis in humans. ==Non Acceptance of Radiation Hormesis== Radiation hormesis has been rejected by both the [[United States National Research Council]] (part of the [[United States National Academy of Sciences|National Academy of Sciences]])<ref>http://books.nap.edu/catalog/11340.html Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2</ref> and the [[National Council on Radiation Protection and Measurements]] (a body commissioned by the [[United States Congress]]).<ref>[http://www.ncrppublications.org/index.cfm?fm=Product.AddToCart&pid=6714063164 NCRP Store - Add Product to Cart<!-- Bot generated title -->]</ref> In addition, the [[United Nations Scientific Committee on the Effects of Atomic Radiation]] (UNSCEAR) wrote in its most recent report:<ref> UNSCEAR 2000 REPORT Vol. II: Sources and Effects of Ionizing Radiation: Annex G: Biological effects at low radiation doses. page 160, paragraph 541. Available online at [http://www.unscear.org/docs/reports/annexg.pdf]. </ref> <blockquote> Until the [...] uncertainties on low-dose response are resolved, the Committee believes that an increase in the risk of tumour induction proportionate to the radiation dose is consistent with developing knowledge and that it remains, accordingly, the most scientifically defensible approximation of low-dose response. However, a strictly linear dose response should not be expected in all circumstances.</blockquote> This is a reference to the fact that very low doses of radiation have only marginal impacts on individual health outcomes. It is therefore difficult to detect the 'signal' of decreased or increased morbidity and mortality due to low-level radiation exposure in the 'noise' of other effects. The notion of radiation hormesis has been rejected by the National Research Council's (part of the National Academy of Sciences) 16 year long study on the Biological Effects of Ionizing Radiation. "The scientific research base shows that there is no threshold of exposure below which low levels of ionizing radiation can be demonstrated to be harmless or beneficial. The health risks – particularly the development of solid cancers in organs – rise proportionally with exposure" says Richard R. Monson, associate dean for professional education and professor of epidemiology, Harvard School of Public Health, Boston [http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=11340]. See the National Academies Press book [http://books.nap.edu/catalog/11340.html Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2]. :''The possibility that low doses of radiation may have beneficial effects (a phenomenon often referred to as “hormesis”) has been the subject of considerable debate. Evidence for hormetic effects was reviewed, with emphasis on material published since the 1990 BEIR V study on the health effects of exposure to low levels of ionizing radiation. Although examples of apparent stimulatory or protective effects can be found in cellular and animal biology, the preponderance of available experimental information does not support the contention that low levels of ionizing radiation have a beneficial effect. The mechanism of any such possible effect remains obscure. At this time, the assumption that any stimulatory hormetic effects from low doses of ionizing radiation will have a significant health benefit to humans that exceeds potential detrimental effects from radiation exposure at the same dose is unwarranted'' [http://books.nap.edu/openbook/030909156X/html/315.html]. :''In chronic low-dose experiments with dogs (75 mGy/d for the duration of life), vital hematopoietic progenitors showed increased radioresistance along with renewed proliferative capacity (Seed and Kaspar 1992). Under the same conditions, a subset of animals showed an increased repair capacity as judged by the unscheduled DNA synthesis assay (Seed and Meyers 1993). Although one might interpret these observations as an adaptive effect at the cellular level, the exposed animal population experienced a high incidence of myeloid leukemia and related myeloproliferative disorders. The authors concluded that “the acquisition of radioresistance and associated repair functions under the strong selective and mutagenic pressure of chronic radiation is tied temporally and causally to leukemogenic transformation by the radiation exposure” (Seed and Kaspar 1992)'' [http://books.nap.edu/openbook/030909156X/html/333.html]. See also [[Hormesis]] under "Non-acceptance". ==Ongoing Debate== Radiation Hormesis is the controversial [[hypothesis]] that low level [[ionizing radiation|radiation]] has negative risk; that [[ionizing radiation]] at levels that occur in the natural environment may increase health by stimulating natural defense mechanisms. Radiation hormesis accepts that radiation above [[background radiation|natural background]] levels has positive risk; that intense artificial radiation, for example, is toxic. The subject of radiation hormesis has captured the attention of scientists and public alike in recent years, perhaps because of its counter-intuitive properties. Opinion pieces on chemical and radiobiological hormesis appeared in the journals [[Nature_%28journal%29|Nature]]<ref name="Calabrese"/> and [[Science_%28journal%29|Science]]<ref name ="Kaiser"/> in 2003. While most major studies have upheld the [[Linear_no-threshold_model|Linear no-threshold model]] (LNT) and rejected the existence of radiation hormesis in humans, according to the 2005 [[French Academy of Science]]-[[French Academy of Medicine|National Academy of Medicine's]] report concerning the effects of low level [[Ionizing_radiation|radiation]] (only they rejected [[Linear_no-threshold_model|LNT]]), 40% of laboratory studies on cell cultures and animals have observed radiobiological hormesis - "''its existence in the laboratory is beyond question and its mechanism of action appears well understood.''"<ref name="Aurengo"/> However, they cautioned that it is not yet known based on laboratory studies if radiation hormesis occurs in humans.<ref name="Aurengo"/> In their 2005 report, the [[French Academy of Sciences]]-[[French Academy of Medicine|National Academy of Medicine]] acknowledged the growing body of research that illustrates that the human body is not a passive accumulator of [[Ionizing_radiation|radiation]] damage but it actively repairs the damage caused via number of different processes, including:<ref name="Aurengo"/> * Mechanisms that mitigate [[Reactive_oxygen_species|reactive oxygen]] species generated by ionising radiation and oxidative stress. * [[Apoptosis]] of [[Ionizing_radiation|radiation]] damaged cells that may undergo [[tumorigenesis]] is initiated at only few mSv. * Cell death during [[meiosis]] of [[Ionizing_radiation|radiation]] damaged cells that were unsuccessfully repaired. * The activation of [[Enzyme|enzymatic]] [[DNA repair]] mechanisms ''c.'' 10 mSv. * The existence of a [[cellular signaling]] system that alerts neighboring cells of cellular damage. * Modern [[DNA microarray]] studies which show that numerous [[genes]] are activated at [[Ionizing_radiation|radiation]] doses well below the level that [[mutagenesis]] is detected. * [[Ionizing_radiation|Radiation]] induced [[tumorigenesis]] may have a threshold related to damage density, as revealed by experiments that employ blocking grids to thinly distribute [[Ionizing_radiation|radiation]]. * A large increase in tumours in [[immunosuppressed]] individuals illustrates that the immune system efficiently destroys aberrant cells and nascent tumours. Examples of studies that observed radioadaptive and hormetic effects include experiments on cells<ref>{{Cite journal | last = Azzam | first = E.I. | coauthors = G.P. Raaphorst, R.E.J. Mitchel | year = 1994 | title = Radiation-Induced Adaptive Response for Protection against Micronucleus Formation and Neoplastic Transformation in C3H 10T1/2 Mouse Embryo Cells | journal = Radiation Research | volume = 138 | issue = 1 | pages = S28–S31 | url = http://links.jstor.org/sici?sici=0033-7587(199404)138%3A1%3CS28%3ARARFPA%3E2.0.CO%3B2-9 | doi = 10.2307/3578755}}</ref><ref>{{Cite journal | last = Azzam | first = E.I. | coauthors = S.M. de Toledo, G.P. Raaphorst, R.E.J. Mitchel | year = 1996. | title = Low-Dose Ionizing Radiation Decreases the Frequency of Neoplastic Transformation to a Level below the Spontaneous Rate in C3H 10T1/2 Cells | journal = Radiation Research | volume = 146 | issue = 4 | pages = 369–373 | doi = 10.2307/3579298 | url = http://links.jstor.org/sici?sici=0033-7587(199610)146%3A4%3C369%3ALIRDTF%3E2.0.CO%3B2-M#abstract }}</ref><ref>{{Cite journal | issn = 00337587 | volume = 162 | issue = 6 | pages = 646–54 | last = Ko | first = S J | coauthors = X-Y Liao, S Molloi, E Elmore, J L Redpath | title = Neoplastic transformation in vitro after exposure to low doses of mammographic-energy X rays: quantitative and mechanistic aspects | journal = Radiation research | url = http://apt.allenpress.com/perlserv/?request=get-abstract&doi=10.1667%2FRR3277&ct=1 | date = 2004-12 | doi = 10.1667/RR3277 }}</ref><ref>{{Cite journal | doi = 10.1093/mutage/gel061 | volume = 22 | issue = 2 | pages = 117–122 | last = Stoilov | first = LM | coauthors = LHF Mullenders, F Darroudi, AT Natarajan | title = Adaptive response to DNA and chromosomal damage induced by X-rays in human blood lymphocytes | journal = Mutagenesis | accessdate = 2008-03-29 | date = 2007-03-01 | url = http://mutage.oxfordjournals.org/cgi/content/abstract/22/2/117 | pmid = 17229819 }}</ref><ref> {{Cite journal | issn = 00275107 | volume = 250 | issue = 1-2 | pages = 299–306 | last = Wolff | first = S | coauthors = R Jostes, F T Cross, T E Hui, V Afzal, J K Wiencke | title = Adaptive response of human lymphocytes for the repair of radon-induced chromosomal damage | journal = Mutation research | url = http://links.jstor.org/sici?sici=0091-6765(199310)101%3C73%3AIORORC%3E2.0.CO%3B2-5 | date = 1991 | month = Oct | year = 1993 | doi = 10.1016/0027-5107(91)90185-Q }}</ref><ref> {{Cite journal | volume = 101 | issue = 3 | pages = 73–77 | last = Wolff | first = S. | coauthors = V. Afzal, R F Jostes, J K Wiencke | title = Indications of repair of radon-induced chromosome damage in human lymphocytes: an adaptive response induced by low doses of X-rays | journal = Environmental Health Perspectives | date = 1993-10 | url = http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1521171 | doi = 10.2307/3431703 | pmid = 8143650 }} </ref>, in animals<ref name = "Calabrese2"/><ref name = "Duport"/><ref>{{Cite journal | volume = 73 | issue = 867 | pages = 298–304 | last = Miyachi | first = Y | title = Acute mild hypothermia caused by a low dose of X-irradiation induces a protective effect against mid-lethal doses of X-rays, and a low level concentration of ozone may act as a radiomimetic | journal = British Journal of Radiology | accessdate = 2008-04-01 | date = 2000-03-01 | url = http://bjr.birjournals.org/cgi/content/abstract/73/867/298 | pmid = 10817047 }}</ref><ref>{{Cite journal | issn = 04493060 | volume = 48 | issue = 2 | pages = 113–20 | last = Pathak | first = Chander Mohan | coauthors = Pramod Kumar Avti, Surender Kumar, Krishan Lal Khanduja, Suresh Chander Sharma | title = Whole body exposure to low-dose gamma radiation promotes kidney antioxidant status in Balb/c mice | journal = Journal of radiation research | url = http://www.jstage.jst.go.jp/article/jrr/48/2/48_113/_article | date = 2007-03 | doi = 10.1269/jrr.06063 }}</ref> and tests on individual humans.<ref>{{Cite journal | doi = 10.1016/j.ics.2004.11.087 | volume = 1276 | pages = 13–16 | last = Ghiassi-Nejad | first = M. | coauthors = M.M. Beitollahi, N. Fallahian, M. Saghirzadeh | title = New findings in the very high natural radiation area of Ramsar, Iran | journal = International Congress Series | accessdate = 2008-04-01 | date = 2005-02 | url = http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B7581-4FJT8MK-8&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=b129ac4ca9010140bac508521ba62967 }}</ref><ref>{{Cite journal | issn = 1424859 | volume = 103 | issue = 1-2 | pages = 40–6 | last = Durante | first = M. | coauthors = G. Snigiryova, E. Akaeva, A. Bogomazova, S. Druzhinin, B. Fedorenko, O. Greco, N. Novitskaya, A. Rubanovich, V. Shevchenko, U. Von Recklinghausen, G. Obe | title = Chromosome aberration dosimetry in cosmonauts after single or multiple space flights | journal = Cytogenetic and Genome Research | date = 2003 | url = http://content.karger.com/ProdukteDB/produkte.asp?Doi=76288 | doi = 10.1159/000076288) | doi_brokendate = 2008-07-04 }}</ref> Another question is the effect of prolonged exposure to low level [[Ionizing_radiation|radiation]] on populations of people. Most epidemiological studies have upheld [[Linear_no-threshold_model|LNT]] and by default reject radiation hormesis, but [[epidemiological]] studies are very difficult do carry out due to compounding factors. For example, a town may have a lower [[cancer]] rate, not because of slightly elevated [[background radiation]] but because it has more new houses with young families who have a lower [[cancer]] rate. The few epidemiological studies that appear to refute [[Linear_no-threshold_model|LNT]] and suggest [[Ionizing_radiation|radiation]] hormesis include, most notably: * [[Bernard Cohen|Bernard Cohen's]] 1995 study of [[lung cancer]] rates vs. average [[radon]] concentration in homes for 1,601 U.S. counties, that questioned the validity [[Linear_no-threshold_model|LNT]].<ref>{{Cite journal | issn = 00179078 | volume = 68 | issue = 2 | pages = 157–74 | last = Cohen | first = B L | title = Test of the linear-no threshold theory of radiation carcinogenesis for inhaled radon decay products | journal = Health physics | date = 1995-02 | url = http://www.health-physics.com/pt/re/healthphys/abstract.00004032-199502000-00002.htm;jsessionid=HnqK0WJNsyMT1Shpv55kn8PNZ68gpXTLfTxwyhsw29PL55N8t79y!1675702673!181195628!8091!-1 }}</ref> * Thompson et al. (2008) 7 year long [[Case-control|case-controlled]] study of residential [[radon]] exposure in Worcester County, [[Massachusetts]], that found an apparent 60% ''reduction'' in [[lung cancer]] risk amongst people exposed to low levels (0-150 Bq/m<sup>3</sup>) of [[radon]] gas; levels typically encountered in 90% of American homes.<ref>{{Cite journal | issn = 00179078 | volume = 94 | issue = 3 | pages = 228–41 | last = Thompson | first = Richard E | coauthors = Donald F Nelson, Joel H Popkin, Zenaida Popkin | title = Case-control study of lung cancer risk from residential radon exposure in Worcester county, Massachusetts | journal = Health physics | url = http://www.health-physics.com/pt/re/healthphys/abstract.00004032-200803000-00002.htm | date = 2008-03 | doi = 10.1097/01.HP.0000288561.53790.5f | doi_brokendate = 2008-07-04 }}</ref> Significantly, both studies reportedly found a very similar exposure/risk relationship curve that appears to match the predictions of radiation hormesis.<ref>Raabe, Otto G. ''Radon hormesis suggested by a careful case-controlled study'' [http://lists.radlab.nl/pipermail/radsafe/2008-February/009450.html] Retrieved on 2008-03-30</ref> Donald Nelson, co-author of Thompson et al. (2008), indicated that the hormetic effect was detected because of the studies application of improved [[radon]] exposure [[dosimetry]].<ref name = "Physorg"> Physorg. Exposure to low levels of radon appears to reduce the risk of lung cancer, new study finds. [http://www.physorg.com/news125672761.html] Retrieved on 2008-03-30</ref> However, a single study cannot be regarded as definitive unless later studies using the same methods of Thompson et al. (2008) [[Reproducibility|reproduce]] the same results.<ref name = "Physorg"/> Additionally, all other studies into the effects of domestic [[radon]] exposure have failed to detect a hormetic effect; including for example the respected "Iowa Radon Lung Cancer Study" of Field et al. (2000), which also used sophisticated radon exposure [[dosimetry]].<ref> {{Cite journal | volume = 151 | issue = 11 | pages = 1091–1102 | last = Field | first = R. William | coauthors = Daniel J. Steck, Brian J. Smith, Christine P. Brus, Eileen L. Fisher, John S. Neuberger, Charles E. Platz, Robert A. Robinson, Robert F. Woolson, Charles F. Lynch | title = Residential Radon Gas Exposure and Lung Cancer: The Iowa Radon Lung Cancer Study | journal = Am. J. Epidemiol. | accessdate = 2008-04-03 | date = 2000-06-01 | url = http://aje.oxfordjournals.org/cgi/content/abstract/151/11/1091 | pmid = 10873134 }} studies </ref> Given the uncertain effects of low level radiation, there is a pressing need for quality research in this area.<ref>"Ultra-Low-Level Radiation Effects Summit." January 2006. ORION International Technologies, Inc. (ORION) and sponsored by the U.S. Department of Energy’s Waste Isolation Pilot Plant (WIPP) 03 Apr. 2008. [http://www.orionint.com/projects/ullre.cfm]</ref> An expert panel convened at the 2006 Ultra-Low-Level Radiation Effects Summit at Carlsbad, New Mexico, proposed the construction of an Ultra-Low-Level Radiation [[laboratory]].<ref>"Ultra-Low-Level Radiation Effects Summit Report." January 2006. ORION International Technologies, Inc. (ORION) and sponsored by the U.S. Department of Energy’s Waste Isolation Pilot Plant (WIPP) 03 Apr. 2008. [http://www.orionint.com/ullre/report-2006.pdf]</ref> The laboratory, if built, will investigate the effects of almost ''no radiation'' on [[laboratory animals]] and [[Cell_culture|cell cultures]], and it will compare these groups to [[control group|control groups]] exposed to natural radiation levels.<ref>"Ultra-Low-Level Radiation Effects Summit - Report Summary." January 2006. ORION International Technologies, Inc. (ORION) and sponsored by the U.S. Department of Energy’s Waste Isolation Pilot Plant (WIPP) 03 Apr. 2008. [http://www.orionint.com/ullre/summary-2006.pdf]</ref> The expert panel believes that the Ultra-Low-Level Radiation laboratory is the only [[experiment]] that can explore with authority and confidence the effects of low level radiation; that it can confirm or discard the various radiobiological effects proposed at low radiation levels e.g. [[Linear_no-threshold_model|LNT]], threshold and radiation hormesis. [[Cadmium]] poisoning is cited as a similar model. It is known that many toxic metals can induce [[oxidative stress]] in tissue which may result in [[free radical]]-induced damage. Also it is known that prior exposure to a small dose of cadmium can mitigate the effects of a second larger dose, this suggests that the first lower dose of the poison stimulates the [[DNA repair]] processes in the exposed tissue. <ref>Wahba, Z. Z.; Hernandez, L.; Issaq, H. J.; Waalkes, M. P. (1990): ''Involvement of sulfhydryl metabolism in tolerance to cadmium in testicular cells''. Toxicology and Applied Pharmacology, 104:157-166.</ref><ref>Waalkes, M. P.; Perantoni, A. (1986): ''Isolation of a novel metal-binding protein from rat testes: characterization and distinction from metallothionein.'' Journal of Biological Chemistry, 261:13079-13103.</ref><ref>Waalkes, M. P.; Rehm, S.; Riggs, C.W.; ''et al.'' (1988): ''Cadmium carcinogenesis in male Wistar (Crl:(WI)BR) rats: dose-response analysis of tumor induction in the prostate and testes, and at the injection site.'' Cancer Research, 48:4656-4663.</ref><ref>Rugstad, H. E.; Norseth, T. (1975): ''Cadmium resistance and content of cadmium-binding protein in cultured human cells.'' Nature, 257:136-137.</ref> ==See also== * [[Hormesis]] * [[Dose fractionation]] * [[Electromagnetic therapy]] * [[Linear no-threshold model]] * [[Petkau effect]] * [[Radioresistance]] ==External links== * [http://library.lanl.gov/cgi-bin/getfile?23-03.pdf" Radiation and Risk: A Hard Look at the Data" by M.E. Schillaci of Los Alamos National Laboratory] - A non-academic magazine article that discusses the hazards of radiation and radiological protection schemes. *[http://books.nap.edu/catalog/11340.html?onpi_newsdoc062905 Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2] *[http://lowdose.tricity.wsu.edu/2001mtg/abstracts/bailey.htm Abstract of a study] showing that radiation increases the rate of natural antioxidant ([[glutathione]]) production. The study found that this does not act as a radiation protection, but seems to protect against other cellular insults such as oxidation. *[http://www.fortfreedom.org/s10.htm History of the idea] by a supporter of the concept. *[http://www.radpro.com/641luckey.pdf Radiation Hormesis Overview] by T. D. Luckey, who wrote a book on the subject (Luckey, T. D. (1991). ''Radiation Hormesis''. Boca Raton, FL: CRC Press. ISBN 0-8493-6159-1) *[http://www.scientificexploration.org/jse/articles/pdf/17.3_kauffman.pdf Radiation Hormesis: Demonstrated, Deconstructed, Denied, Dismissed, and Some Implications for Public Policy] by Joel M. Kauffman: "evidence is presented that chronic doses up to 100 times those of normal ambient (including medical) exposures are beneficial..." *[http://www.sciencedaily.com/releases/2008/03/080325122807.htm Exposure To Low Levels Of Radon Appears To Reduce The Risk Of Lung Cancer] From Sciencedaily.com * [http://www.wpi.edu/News/Releases/20078/radonstudy.html News release from the Worcester Polytechnic Institute] describing the study of Thompson et al. (2008) that found low levels of radon gas appears to reduce the risk of Lung Cancer. ==References== {{reflist|2}} [[Category:Radiobiology]] [[Category:Radiation health effects]] [[pl:Hormeza radiacyjna]] [[ru:Гормезис]]