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| {{Infobox isotope
| | My name is Seymour (43 years old) and my hobbies are Gardening and Association football.<br><br>Stop by my homepage :: [http://Www.Panthers.Gildenseite.de/index.php?mod=users&action=view&id=14627 Fifa coin Generator] |
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| | alternate_names =Radioiodine
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| | symbol =I
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| | mass_number =131
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| | mass =130.9061246(12)
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| | num_neutrons =78
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| | num_protons =53
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| | abundance =
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| | halflife =8.0197 days
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| | error_halflife =
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| | background =#c9F
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| | excess_energy = 971
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| '''Iodine-131''' ('''<sup>131</sup>I'''), also called '''radioiodine''', is an important [[radioisotope]] of [[iodine]]. It has a radioactive decay half-life of about eight days. It is associated with nuclear energy, medical diagnostic and treatment procedures, and natural gas production. It also plays a major role as a radioactive isotope present in [[nuclear fission]] products, and was a significant contributor to the health hazards from open-air atomic bomb testing in the 1950s, and from the [[Chernobyl disaster]], as well as being a large fraction of the contamination hazard in the first weeks in the [[Fukushima I nuclear accidents|Fukushima nuclear crisis]]. This is because I-131 is a major [[uranium]], [[plutonium]] [[fission product]], comprising nearly 3% of the total products of fission (by weight). See [[fission product yield]] for a comparison with other radioactive fission products. I-131 is also a major fission product of uranium-233, produced from [[thorium]].
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| Due to its mode of [[beta decay]], iodine-131 is notable for causing [[mutation]] and death in cells that it penetrates, and other cells up to several millimeters away. For this reason, high doses of the isotope are sometimes less dangerous than low doses, since they tend to kill [[thyroid]] tissues that would otherwise become cancerous as a result of the radiation. For example, children treated with moderate dose of I-131 for thyroid adenomas had a detectable increase in thyroid cancer, but children treated with a much higher dose did not. Likewise, most studies of very-high-dose I-131 for treatment of [[Graves disease]] have failed to find any increase in thyroid cancer, even though there is linear increase in thyroid cancer risk with I-131 absorption at moderate doses.<ref name="Rivkees">{{cite journal |doi=10.1210/jc.83.11.3767 |title=The Management of Graves' Disease in Children, with Special Emphasis on Radioiodine Treatment |year=1998 |last1=Rivkees |first1=Scott A. |first2=Charles |last2=Sklar |first3=Michael |last3=Freemark |journal=Journal of Clinical Endocrinology & Metabolism |volume=83 |issue=11 |pmid=9814445 |pages=3767–76}}</ref> Thus, iodine-131 is increasingly less employed in small doses in medical use (especially in children), but increasingly is used only in large and maximal treatment doses, as a way of killing targeted tissues. This is known as "therapeutic use."
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| Iodine-131 can be "seen" by [[nuclear medicine]] imaging techniques (i.e., [[gamma camera]]s) whenever it is given for therapeutic use, since about 10% of its energy and radiation dose is via gamma radiation. However, since the other 90% of radiation (beta radiation) causes tissue damage without contributing to any ability to see or "image" the isotope, other less-damaging radioisotopes of iodine are preferred in situations when ''only'' nuclear imaging is required. The isotope I-131 is still occasionally used for purely diagnostic (i.e., imaging) work, due to its low expense compared to other iodine radioisotopes. Very small medical imaging doses of I-131 have not shown any increase in thyroid cancer. The low-cost availability of I-131, in turn, is due to the relative ease of creating I-131 by neutron bombardment of natural [[tellurium]] in a nuclear reactor, then separating I-131 out by various simple methods (i.e., heating to drive off the volatile iodine). By contrast, other iodine radioisotopes are usually created by far more expensive techniques, starting with reactor radiation of expensive capsules of pressurized [[xenon]] gas.
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| Iodine-131 is also one of the most commonly used gamma-emitting [[radioactive tracer#Applications|radioactive industrial tracer]]. Radioactive tracer isotopes are injected with [[hydraulic fracturing]] fluid to determine the injection profile and location of fractures created by hydraulic fracturing.<ref name="Reis_iodine" />
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| Much smaller incidental doses of iodine-131 than those used in medical therapeutic procedures, are thought to be the major cause of [[radiation-induced cancer|increased thyroid cancer]]s after accidental nuclear contamination.<ref name="Simon">{{cite journal|last1=Simon|first1=Steven L.|first2=André |last2=Bouville |first3=Charles E. |last3=Land|title=Fallout from Nuclear Weapons Tests and Cancer Risks|journal=American Scientist|date=January–February 2006|volume=94|pages=48–57| doi=10.1511/2006.1.48 |quote=In 1997, NCI conducted a detailed evaluation of dose to the thyroid glands of U.S. residents from I-131 in fallout from tests in Nevada. (...) we evaluated the risks of thyroid cancer from that exposure and estimated that about 49,000 fallout-related cases might occur in the United States, almost all of them among persons who were under age 20 at some time during the period 1951–57, with 95-percent uncertainty limits of 11,300 and 212,000.}}</ref><ref>{{cite web|url=https://ntsi131.nci.nih.gov/ |title=National Cancer Institute calculator for thyroid cancer risk as a result of I-131 intake after nuclear testing before 1971 in Nevada |publisher=Ntsi131.nci.nih.gov |date= |accessdate=2012-06-17}}</ref><ref>{{cite journal|last1=Guiraud-Vitaux|first1=F.|last2=Elbast|first2= M.|last3= Colas-Linhart|first3= N.|last4= Hindie|first4= E.|title=Thyroid cancer after Chernobyl: is iodine 131 the only culprit ? Impact on clinical practice|journal=Bulletin du cancer|date=February 2008|volume=95|issue=2|pages=191–5|pmid=18304904|doi=10.1684/bdc.2008.0574}}</ref><ref>{{cite book|title=The Hanford Thyroid Disease Study|year=2002|url=http://www.cdc.gov/nceh/radiation/hanford/htdsweb/pdf/htdsreport.pdf|author=[[Centre for Disease Control]]|accessdate=17 June 2012|quote=no associations between
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| Hanford’s iodine-131 releases and thyroid disease were observed. [The findings] show that if there is an increased risk of thyroid disease from exposure to Hanford’s iodine-131, it is probably too small to observe using the best epidemiologic methods available}} [http://www.cdc.gov/nceh/radiation/hanford/htdsweb/pdf/htds_aag.pdf Executive summary]</ref> These cancers happen from residual tissue radiation damage caused by the I-131, and usually appear years after exposure, long after the I-131 has decayed.<ref name="Simon"/>
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| ==Production==
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| Most I-131 production is from nuclear reactor neutron-[[irradiation]] of a natural [[tellurium]] target. Irradiation of natural tellurium produces almost entirely I-131 as the only radionuclide with a half-life longer than hours, since most lighter [[isotopes of tellurium]] become heavier stable isotopes, or else stable iodine or xenon. However, the heaviest naturally-occurring tellurium nuclide, Te-130 (34% of natural Te) absorbs a neutron to become tellurium-131, which beta-decays with a half-life of 25 minutes, to I-131.
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| A tellurium compound can be irradiated while bound as an oxide to an ion exchange column, and evolved I-131 then [[eluted]] into an alkaline solution.<ref>{{cite journal |doi=10.1016/j.apradiso.2010.04.033 |title=Recovery of 131I from alkaline solution of n-irradiated tellurium target using a tiny Dowex-1 column |year=2010 |last1=Chattopadhyay |first1=Sankha |last2=Saha Das |first2=Sujata |journal=Applied Radiation and Isotopes |volume=68 |issue=10 |pages=1967–9 |pmid=20471848}}</ref> More commonly, powdered elemental tellurium is irradiated and then I-131 separated from it by dry distillation of the iodine, which has a far higher vapor pressure. The element is then dissolved in a mildly alkaline solution in the standard manner, to produce I-131 as iodide and hypoiodate (which is soon reduced to iodide).<ref>{{cite web |date=August 2011 |url=http://www.mds.nordion.com/documents/products/I-131_Solu_Can.pdf |title=I-131 Fact Sheet |publisher=Nordion |accessdate=2010-10-26}}</ref>
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| <sup>131</sup>I is a [[fission product]] with a [[fission product yield|yield]] of 2.878% from [[uranium-235]],<ref>{{cite web |url=http://www-nds.iaea.org/sgnucdat/c3.htm |title=Nuclear Data for Safeguards, Table C-3, Cumulative Fission Yields |author= |date= |work= |publisher=International Atomic Energy Agency |accessdate=14 March 2011}} (thermal neutron fission)</ref> and can be released in [[nuclear weapons tests]] and [[nuclear accident]]s. However, the short half-life means it is not present in significant quantities in cooled [[spent nuclear fuel]], unlike [[iodine-129]] whose half-life is nearly a billion times that of I-131.
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| ==Radioactive decay==
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| [[File:Iodine-131-decay-scheme-simplified.svg|thumb|left|300px|Iodine-131 decay scheme (simplified)]]
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| I-131 decays with a [[half-life]] of 8.02 days with [[beta emission|beta minus]] and [[gamma ray|gamma]] emissions. This [[nuclide]] of iodine has 78 [[neutron]]s in its nucleus, while the only stable nuclide, <sup>127</sup>I, has 74. On decaying, <sup>131</sup>I most often (89% of the time) expends its 971 keV of decay energy by transforming into the stable <sup>[[Xenon-131|131]]</sup>[[Xenon-131|Xe]] (Xenon) in two steps, with gamma decay following rapidly after beta decay:
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| <math>{^{131}_{53}\mathrm{I}} \rightarrow \beta + \bar{\nu_e} + {^{131}_{54}\mathrm{Xe}^*} </math> '''+ 606 keV'''
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| :
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| :
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| <math>{^{131}_{54}\mathrm{Xe}^*} \rightarrow {^{131}_{54}\mathrm{Xe}} + \gamma </math> '''+ 364 keV'''
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| The primary emissions of <sup>131</sup>I decay are thus electrons with a maximal energy of 606 keV (89% abundance, others 248–807 keV) and 364 keV gamma rays (81% abundance, others 723 keV).<ref>{{cite web | url = http://hpschapters.org/northcarolina/NSDS/131IPDF.pdf | title = Nuclide Safety Data Sheet| accessdate=2010-10-26}}</ref> Beta decay also produces an [[antineutrino]], which carries off variable amounts of the beta decay energy. The electrons, due to their high mean energy (190 keV, with typical beta-decay spectra present) have a tissue penetration of 0.6 to 2 mm.<ref>{{cite book |isbn=978-1-59624-021-6 |page=82|title=Thyroid Disorders |series=A Cleveland Clinic Guide |first=Mario |last=Skugor |publisher=Cleveland Clinic Press |year=2006}}</ref>
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| ==Effects of exposure==
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| [[File:US fallout exposure.png|right|thumb|Per capita [[thyroid]] doses in the continental United States resulting from all exposure routes from all atmospheric [[nuclear testing|nuclear tests]] conducted at the [[Nevada Test Site]] from 1951-1962. A [[Centers for Disease Control and Prevention]]/ [[National Cancer Institute]] study claims that nuclear fallout might have led to approximately 11,000 excess deaths, most caused by [[thyroid cancer]] linked to exposure to [[iodine-131]].<ref>[http://books.nap.edu/catalog.php?record_id=10621 Exposure of the American Population to Radioactive Fallout from Nuclear Weapons Tests]</ref>]]
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| Iodine in food is absorbed by the body and preferentially concentrated in the [[thyroid]] where it is needed for the functioning of that gland. When <sup>131</sup>I is present in high levels in the environment from radioactive [[fallout]], it can be absorbed through contaminated food, and will also accumulate in the thyroid. As it decays, it may cause damage to the thyroid. The primary risk from exposure to high levels of <sup>131</sup>I is the chance occurrence of [[radiogenic]] [[thyroid cancer]] in later life. Other risks include the possibility of non-cancerous growths and [[thyroiditis]].<ref name="Rivkees"/>
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| The risk of thyroid cancer in later life appears to diminish with increasing age at time of exposure. Most risk estimates are based on studies in which radiation exposures occurred in [[children]] or teenagers. When adults are exposed, it has been difficult for epidemiologists to detect a statistically significant difference in the rates of thyroid disease above that of a similar but otherwise-unexposed group.<ref name="Rivkees"/>
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| The risk can be mitigated by taking iodine supplements, raising the total amount of iodine in the body and, therefore, reducing uptake and retention in the face and chest and lowering the relative proportion of radioactive iodine. However, such supplements were not distributed to the population living nearest to the [[Chernobyl disaster|Chernobyl]] nuclear power plant after the disaster,<ref>{{cite web|url=http://www.ecolo.org/documents/documents_in_english/Causes.ChernobyJF.doc |title=THE CAUSES OF THE CHERNOBYL EVENT |publisher=Ecolo.org |date= |accessdate=2012-06-17 |first=Jacques |last=Frot}}</ref> though they were widely distributed to children in Poland.
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| Within the USA, the highest <sup>131</sup>I fallout doses occurred during the 1950s and early 1960s to children having consumed fresh sources of milk contaminated as the result of above-ground testing of nuclear weapons.<ref name="Simon"/> The [[National Cancer Institute]] provides additional information on the health effects from exposure to <sup>131</sup>I in fallout,<ref>{{cite web |title=Radioactive I-131 from Fallout |url=http://www.cancer.gov/i131 |publisher=National Cancer Institute |accessdate=2007-11-14}}</ref> as well as individualized estimates, for those born before 1971, for each of the 3070 counties in the USA. The calculations are taken from data collected regarding fallout from the nuclear weapons tests conducted at the [[Nevada Test Site]].<ref>{{cite web |title=Individual Dose and Risk Calculator for Nevada Test Site fallout |url=http://ntsi131.nci.nih.gov/ |date=10/01/07 |publisher=National Cancer Institute |accessdate=2007-11-14}}</ref>
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| On 27 March 2011, the Massachusetts Department of Public Health reported that <sup>131</sup>I was detected in very low concentrations in rainwater from samples collected in Massachusetts, USA, and that this likely originated from the Fukushima power plant.<ref>{{cite web|url=http://www.thebostonchannel.com/r-video/27338488/detail.html |title=Low Concentrations Of Radiation Found In Mass. | WCVB Home - WCVB Home |publisher=Thebostonchannel.com |date=2011-03-27 |accessdate=2012-06-17}}</ref> Farmers near the plant dumped raw milk, while testing in the United States found 0.8 pico-curies per liter of iodine-131 in a milk sample, but the radiation levels were 5,000 times lower than the FDA's "defined intervention level."
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| The levels were expected to drop relatively quickly<ref>[http://www.latimes.com/news/nationworld/nation/la-fgw-japan-radiation-milk-20110331,0,4354119.story?track=rss "Traces of radioactive iodine found in Washington state milk" Los Angeles Times]{{dead link|date=June 2012}}</ref>
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| ===Treatment and prevention===
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| {{See also|Potassium iodide}}
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| A common treatment method for preventing iodine-131 exposure is by saturating the thyroid with regular, non-radioactive iodine-127, as an iodide or [[iodate]] salt. Free elemental iodine should not be used for saturating the thyroid because it is a corrosive oxidant and therefore is toxic to ingest in the necessary quantities{{Citation needed|date=March 2011}}. The thyroid will absorb very little of the radioactive iodine-131 after it is saturated with non-radioactive iodide, thereby avoiding the [[Radiation poisoning|damage caused by radiation]] from radioiodine. The most common method of treatment is to give potassium iodide to those at risk. The dosage for adults is 130 mg potassium iodide per day, given in one dose, or divided into portions of 65 mg twice a day. This is equivalent to 100 mg of iodide, and is about 7000 times bigger than the nutritional dose of iodide, which is 0.015 mg per day (150 [[microgram]]s per day). See [[potassium iodide]] for more information on prevention of radioiodine absorption by the thyroid during nuclear accident, or for [[nuclear medicine|nuclear medical]] reasons. The FDA-approved dosing of potassium iodide for this purpose are as follows: infants less than 1 month old, 16 mg; children 1 month to 3 years, 32 mg; children 3 years to 18 years, 65 mg; adults 130 mg.<ref>Kowalsky RJ, Falen, SW. Radiopharmaceuticals in Nuclear Pharmacy and Nuclear Medicine. 2nd ed. Washington DC: American Pharmacists Association; 2004.</ref> However, some sources recommend alternative dosing regimens.<ref name="eanm">https://www.eanm.org/scientific_info/guidelines/gl_paed_mibg.pdf?PHPSESSID=46d05b62d235c36a12166bf939b656c7</ref>
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| {| class="wikitable"
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| |+ The [[World Health Organization]]s daily recommended Dosage for Radiological Emergencies involving radioactive iodine<ref>{{Citation
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| | publication-date = 1999
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| | title = Guidelines for Iodine Prophylaxis following Nuclear Accidents
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| | publication-place =
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| | place = Geneva
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| | publisher = [[World Health Organization]]
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| | url = http://www.who.int/ionizing_radiation/pub_meet/Iodine_Prophylaxis_guide.pdf
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| }}</ref>
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| ! Age
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| ! [[potassium iodide|KI]] in mg
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| ! [[potassium iodate|KIO<sub>3</sub>]] in mg
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| |-
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| | Over 12 years old
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| | 130
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| | 170
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| |-
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| | 3 – 12 years old
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| | 65
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| | 85
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| |-
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| | 1 – 36 months old
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| | 32
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| | 42
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| |-
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| | < 1 month old
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| | 16
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| | 21
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| |}
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| The ingestion of prophylaxis iodide & [[iodate]] is not without its dangers, There is reason for caution about taking potassium iodide or iodine supplements, as their unnecessary use can cause conditions such as the [[Jod-Basedow phenomena]], and the [[Wolff-Chaikoff effect]], trigger and/or worsen [[hyperthyroidism]] and [[hypothyroidism]] respectively, and ultimately cause temporary or even permanent thyroid conditions. It can also cause [[sialadenitis]] (an inflammation of the salivary gland), gastrointestinal disturbances, allergic reactions and rashes. Potassium iodide is also not recommended for those who have had an allergic reaction to iodine, and people with dermatitis herpetiformis and hypocomplementemic vasculitis, conditions that are linked to a risk of iodine sensitivity.<ref>{{cite web|url=http://www.thyroid-info.com/potassium-iodide.htm |title=Information on Radiation, Health and the Thyroid, Including Iodine Testing, Potassium Iodide, and Thyroid Testing |publisher=Thyroid-info.com |date= |accessdate=2012-06-17}}</ref>
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| The use of a particular 'Iodine tablet' used in [[portable water purification]] has also been determined as somewhat effective at reducing radioiodine uptake. In a small study on human subjects, who for each of their 90 day trial, ingested four 20 milligram tetraglycine hydroperiodide(TGHP) water tablets, with each tablet releasing 8 milligrams (ppm) of free titratable iodine;<ref>http://www.pharmacalway.com/FAQ.html</ref> it was found that the biological uptake of radioactive iodine in these human subjects dropped to, and remained at, a value of less than 2% the radioiodine uptake rate of that observed in control subjects who went fully exposed to radioiodine without treatment.<ref>{{cite web|last=LeMar et al|first=HJ|title=''Thyroid adaptation to chronic tetraglycine hydroperiodide water purification tablet use.'' Department of Medicine, Madigan Army Medical Center, Tacoma, Washington 98431.|url=http://jcem.endojournals.org/content/80/1/220.short|work=Journal of Clinical Endocrinology & Metabolism, Vol 80, 220-223, doi: 10.1210/jc.80.1.220 Copyright © 1995|publisher=Endocrine Society|accessdate=20 Mar 2010}}</ref>
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| The administration of known [[goitrogen]] substances can also be used as a [[prophylaxis]] in reducing the bio-uptake of iodine, (whether it be the nutritional non-radioactive [[iodine-127]] or radioactive iodine, radioiodine - most commonly iodine-131, as the body cannot discern between different iodine [[isotopes]]).
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| [[Perchlorate]] ions, a common water contaminant in the USA due to the [[aerospace industry]], has been shown to reduce iodine uptake and thus is classified as a [[goitrogen]]. Perchlorate ions are a competitive inhibitor of the process by which iodide, is actively deposited into thyroid follicular cells. Studies involving healthy adult volunteers determined that at levels above 0.007 milligrams per kilogram per day (mg/(kg·d)), perchlorate begins to temporarily inhibit the thyroid gland’s ability to absorb iodine from the bloodstream ("iodide uptake inhibition", thus perchlorate is a known goitrogen).<ref name=pmid12204829>{{cite journal |doi=10.1289/ehp.02110927 |title=Health Effects Assessment for Environmental Perchlorate Contamination: The Dose Response for Inhibition of Thyroidal Radioiodine Uptake in Humans |year=2002 |last1=Greer |first1=Monte A. |last2=Goodman |first2=Gay |last3=Pleus |first3=Richard C. |last4=Greer |first4=Susan E. |journal=Environmental Health Perspectives |volume=110 |issue=9 |pages=927–37 |pmid=12204829 |pmc=1240994}}</ref>
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| The reduction of the iodide pool by perchlorate has dual effects—reduction of excess hormone synthesis and hyperthyroidism, on the one hand, and reduction of thyroid inhibitor synthesis and hypothyroidism on the other. Perchlorate remains very useful as a single dose application in tests measuring the discharge of radioiodide accumulated in the thyroid as a result of many different disruptions in the further metabolism of iodide in the thyroid gland.<ref name=pmid9549759>{{cite journal |pmid=9549759 |year=1998 |last1=Wolff |first1=J |title=Perchlorate and the thyroid gland |volume=50 |issue=1 |pages=89–105 |journal=Pharmacological reviews}}</ref>
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| Treatment of thyrotoxicosis (including Graves' disease) with 600-2,000 mg potassium perchlorate (430-1,400 mg perchlorate) daily for periods of several months or longer was once common practice, particularly in Europe,<ref name=pmid12204829/><ref>{{cite journal |pmid=4290684 |year=1966 |last1=Barzilai |first1=D |last2=Sheinfeld |first2=M |title=Fatal complications following use of potassium perchlorate in thyrotoxicosis. Report of two cases and a review of the literature |volume=2 |issue=4 |pages=453–6 |journal=Israel journal of medical sciences}}</ref> and perchlorate use at lower doses to treat thryoid problems continues to this day.<ref>{{cite journal |doi=10.1007/s00108-005-1508-4 |title=Therapie und Prävention der Hyperthyreose |trans_title=Therapy and prevention of hyperthyroidism |language=German |year=2005 |last1=Woenckhaus |first1=U. |last2=Girlich |first2=C. |journal=Der Internist |volume=46 |issue=12 |pages=1318–23 |pmid=16231171}}</ref> Although 400 mg of potassium perchlorate divided into four or five daily doses was used initially and found effective, higher doses were introduced when 400 mg/day was discovered not to control thyrotoxicosis in all subjects.<ref name=pmid12204829/><ref name=pmid9549759/>
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| Current regimens for treatment of [[thyrotoxicosis]] (including Graves' disease), when a patient is exposed to additional sources of iodine, commonly include 500 mg potassium perchlorate twice per day for 18–40 days.<ref name=pmid12204829/><ref name=pmid8768854>{{cite journal |doi=10.1210/jc.81.8.2930 |title=Treatment of amiodarone-induced thyrotoxicosis, a difficult challenge: Results of a prospective study |year=1996 |last1=Bartalena |first1=L. |journal=Journal of Clinical Endocrinology & Metabolism |volume=81 |issue=8 |pmid=8768854 |pages=2930–3 |last2=Brogioni |first2=S |last3=Grasso |first3=L |last4=Bogazzi |first4=F |last5=Burelli |first5=A |last6=Martino |first6=E}}</ref>
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| Prophylaxis with perchlorate containing water at concentrations of 17 [[Parts per million|ppm]], which corresponds to 0.5 mg/kg-day personal intake, if one is 70 kg and consumes two litres of water per day, was found to reduce baseline radioiodine uptake by 67%<ref name=pmid12204829/> This is equivalent to ingesting a total of just 35 mg of perchlorate ions per day. In another related study were subjects drank just 1 litre of perchlorate containing water per day at a concentration of 10 ppm, i.e. daily 10 mg of perchlorate ions were ingested, an average 38% reduction in the uptake of iodine was observed.<ref>{{cite journal |doi=10.1089/10507250050137734 |title=The Effect of Short-Term Low-Dose Perchlorate on Various Aspects of Thyroid Function |year=2000 |last1=Lawrence |first1=J. E. |last2=Lamm |first2=S. H. |last3=Pino |first3=S. |last4=Richman |first4=K. |last5=Braverman |first5=L. E. |journal=Thyroid |volume=10 |issue=8 |pages=659–63 |pmid=11014310}}</ref>
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| However when the average perchlorate absorption in perchlorate plant workers subjected to the highest exposure has been estimated as approximately 0.5 mg/kg-day, as in the above paragraph, a 67% reduction of iodine uptake would be expected. Studies of chronically exposed workers though have thus far failed to detect any abnormalities of thyroid function, including the uptake of iodine.<ref>{{cite journal |doi=10.1097/00043764-199904000-00006 |title=Thyroid Health Status of Ammonium Perchlorate Workers: A Cross-Sectional Occupational Health Study |year=1999 |last1=Lamm |first1=Steven H. |last2=Braverman |first2=Lewis E. |last3=Li |first3=Feng Xiao |last4=Richman |first4=Kent |last5=Pino |first5=Sam |last6=Howearth |first6=Gregory |journal=Journal of Occupational & Environmental Medicine |volume=41 |issue=4 |pmid=10224590 |pages=248–60}}</ref> this may well be attributable to sufficient daily exposure or intake of healthy iodine-127 among the workers and the short 8 hr [[biological half life]] of perchlorate in the body.<ref name=pmid12204829/>
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| To completely block the uptake of iodine-131 by the purposeful addition of perchlorate ions to a populaces water supply, aiming at dosages of 0.5 mg/kg-day, or a water concentration of 17 ppm, would therefore be grossly inadequate at truly reducing radioiodine uptake. Perchlorate ion concentrations in a regions water supply, would therefore need to be much higher, with at least a total dosage of 7.15 mg/kg of body weight per day needing to be aimed for, with this being achievable for most adults by consuming 2 liters of water per day with a water concentration of 250 mg/kg of water or 250 ppm of perchlorate ions per liter, only at this level would perchlorate consumption offer adequate protection, and be truly beneficial to the population at preventing [[bioaccumulation]] when exposed to a radioiodine environment.<ref name=pmid12204829/><ref name=pmid8768854/> This being entirely independent of the availability of [[iodate]] or [[iodide]] drugs.
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| The continual addition of perchlorate to the water supply would need to continue for no less than 80–90 days, beginning immediately after the initial release of radioiodine was detected, after 80–90 days had passed released radioactive iodine-131 would have decayed to less than 0.1% of its initial quantity and thus the danger from biouptake of iodine-131 is essentially over.<ref>{{cite web|url=http://www.dummies.com/how-to/content/nuclear-chemistry-halflives-and-radioactive-dating.html |title=Nuclear Chemistry: Half-Lives and Radioactive Dating - For Dummies |publisher=Dummies.com |date=2010-01-06 |accessdate=2012-06-17}}</ref>
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| In the event of a radioiodine release the ingestion of prophylaxis potassium iodide or iodate, if available, would rightly take precedence over perchlorate administration and would be the first line of defense in protecting the population from a radioiodine release. However in the event of a radioiodine release too massive and widespread to be controlled by the limited stock of iodide & iodate prophylaxis drugs, then the addition of perchlorate ions to the water supply, or distribution of perchlorate tablets would serve as a cheap, efficacious, second line of defense against [[carcinogenic]] radioiodine bioaccumulation.
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| The ingestion of goitrogen drugs is, much like [[potassium iodide]] is also not without its dangers, such as [[hypothyroidism]]. In all these cases however, despite the risks, the prophylaxis benefits of intervention with iodide, iodate or perchlorate outweigh the serious cancer risk from radioiodine [[bioaccumulation]] in regions were radioiodine has sufficiently contaminatated the environment.
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| ==Medical and pharmaceutical uses==
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| [[File:Pheochromocytoma Scan.jpg|thumb|upright|A [[pheochromocytoma]] tumor is seen as a dark sphere in the center of the body (it is in the left adrenal gland). The image is by [[MIBG]] [[scintigraphy]], showing the tumor by radiation from radioiodine in the MIBG. Two images are seen of the same patient from front and back. The image of the thyroid in the neck is due to unwanted uptake of radioiodine (as iodide) by the thyroid, after breakdown of the radioactive iodine-containing medication. Accumulation at the sides of the head is from salivary gland uptake of radioiodide. Radioactivity is also seen from uptake by the liver, and excretion by the kidneys with accumulation in the bladder.]]
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| It is used in [[nuclear medicine]] therapeutically and can also be seen with diagnostic scanners if it has been used therapeutically. Use of the <sup>131</sup>I as iodide salt exploits the mechanism of absorption of iodine by the normal cells of the [[thyroid]] gland. Examples of its use in [[radiation therapy]] are those where tissue destruction is desired after iodine uptake by the tissue.
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| Major uses of <sup>131</sup>I include the treatment of [[thyrotoxicosis]] (hyperthyroidism) and some types of [[thyroid cancer]] that absorb iodine. The <sup>131</sup>I is thus used as direct [[radioisotope therapy]] to treat [[hyperthyroidism]] due to [[Graves' disease]], and sometimes hyperactive thyroid nodules (abnormally active thyroid tissue that is not malignant). The therapeutic use of radioiodine to treat hyperthyroidism from Graves' disease was first reported by [[Saul Hertz]] in 1941.
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| The <sup>131</sup>I isotope is also used as a radioactive label for certain [[radiopharmaceutical]]s that can be used for therapy, e.g. <sup>131</sup>I-[[metaiodobenzylguanidine]] (<sup>131</sup>I-MIBG) for imaging and treating [[pheochromocytoma]] and [[neuroblastoma]]. In all of these therapeutic uses, <sup>131</sup>I destroys tissue by short-range [[beta decay|beta radiation]]. About 90% of its radiation damage to tissue is via beta radiation, and the rest occurs via its gamma radiation (at a longer distance from the radioisotope). It can be seen in diagnostic scans after its use as therapy, because <sup>131</sup>I is also a gamma-emitter.
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| Because of the carcinogenicity of its beta radiation in the thyroid in small doses, I-131 is rarely used primarily or solely for diagnosis (although in the past this was more common due to this isotope's relative ease of production and low expense). Instead the more purely gamma-emitting radioiodine [[iodine-123]] is used in diagnostic testing ([[nuclear medicine]] scan of the thyroid). The longer half-lived [[iodine-125]] is also occasionally used when a longer half-life radioiodine is needed for diagnosis, and, in [[brachytherapy]] treatment (isotope confined in small seed-like metal capsules), where the low-energy gamma radiation without a beta component, makes iodine-125 useful. The other radioisotopes of iodine are never used in brachytherapy.
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| The use of <sup>131</sup>I as a medical isotope has been blamed for a routine shipment of [[biosolids]] being rejected from crossing the Canada—U.S. border.<ref>{{cite news |title=Medical isotopes the likely cause of radiation in Ottawa waste |url=http://www.cbc.ca/canada/story/2009/02/04/ot-090204-isotopes.html| date=04/02/09 |publisher=CBCnews|accessdate=2009-02-09}}</ref> Such material can enter the sewers directly from the medical facilities, or by being excreted by patients after a treatment.
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| ===Administration of therapeutic I-131===
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| Because the total radioactivity of a dose of I-131 is usually high, and because the local beta radiation of nearby stomach tissue from an undissolved capsule is high, I-131 is usually administered to human patients in a small drink containing a few ounces of fluid. This is often slowly and carefully sucked out of a shielded container to prevent spillage.<ref>[http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2934601/ Administration technique]</ref> For administration to animals (for example, cats with hyperthyroidism) for practical reasons the isotope must be administered by injection.
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| ===Post-treatment isolation===
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| Patients receiving I-131 radioiodine treatment are warned not to have sexual intercourse for one month (or shorter, depending on dose given), and women are told not to become pregnant for six months afterwards. "This is because a theoretical risk to a developing fetus exists, even though the amount of radioactivity retained may be small and there is no medical proof of an actual risk from radioiodine treatment. Such a precaution would essentially eliminate direct fetal exposure to radioactivity and markedly reduce the possibility of conception with sperm that might theoretically have been damaged by exposure to radioiodine."<ref>{{cite web | title = Radioiodine Therapy: Information for Patients | publisher = AACE | year = 2004 | url = http://www.kumc.edu/endocrine/Radioiodine_Therapy.pdf}}</ref> These guidelines vary from hospital to hospital and will depend also on the dose of radiation given. Some also advise not to hug or hold children when the radiation is still high, and a one or two metre distance to others may be recommended.<ref>{{cite web |title=Instructions for Receiving Radioactive Iodine Therapy after a Thyroid Cancer Survey |url=http://uwmedicine.washington.edu/PatientCare/MedicalSpecialties/SpecialtyCare/UWMEDICALCENTER/Radiology/instructionsthyroidcancersurvey.htm |publisher=University of Washington Medical Center |accessdate=2009-04-12}} {{Dead link|date=October 2010|bot=H3llBot}}</ref>
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| I-131 will be eliminated from the body over the next several weeks after it is given. The majority of I-131 will be eliminated from the human body in 3–5 days, through natural decay, and through excretion in sweat and urine. Smaller amounts will continue to be released over the next several weeks, as the body processes thyroid hormones created with the I-131. For this reason, it is advised to regularly clean toilets, sinks, bed sheets and clothing used by the person who received the treatment. Patients may also be advised to wear slippers or socks at all times, and themselves physically isolated from others. This minimizes accidental exposure by family members, especially children.<ref>{{cite web|title=Precautions after Out-patient Radioactive Iodine (I-131) Therapy|url=http://www.hamiltonhealthsciences.ca/documents/Patient%20Education/I131RadioactiveIodineTherapyHHS-trh.pdf|publisher=Department of Nuclear Medicine McMaster University Medical Centre}}</ref> Use of a decontaminant specially made for radioactive iodine removal may be advised. The use of chlorine bleach solutions, or cleaners that contain chlorine bleach for cleanup, are not advised, since radioactive elemental iodine gas may be released.<ref name="Biosafety Manual for Perdue University">{{cite book|title=Biosafety Manual for Perdue University|year=2002|location=Indianapolis|page=7|url=http://www.ehs.iupui.edu/biohaz_manual/biosafety_manual_v0502.pdf}}</ref> Airborne I-131 may cause a greater risk of second-hand exposure, spreading contamination over a wide area.
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| Many airports now have radiation detectors to detect the smuggling of radioactive materials that may be used in nuclear weapons manufacture. Patients should be warned that if they travel by air, they may trigger radiation detectors at airports up to 95 days after their treatment with <sup>131</sup>I.<ref>{{cite news | last = Sutton | first =Jane | title = Radioactive patients | publisher = reuters | date = 2007-01-29 | url = http://www.reuters.com/article/health-SP-A/idUSN2633076820070209?pageNumber=2 | accessdate = 2009-05-15 }}</ref>
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| ==Industrial radioactive tracer uses==
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| Used for the first time in 1951 to localize leaks in a drinking water supply system of [[Munich]], Germany, iodine-131 became one of the most commonly used gamma-emitting industrial [[radioactive tracer]] with applications in [[isotope hydrology]] and leak detection.<ref>{{cite book|last1=Moser |last2=Rauert|first1=H.|first2=W. |title=Isotopes in the water cycle : past, present and future of a developing science|year=2007|publisher=Springer|location=Dordrecht|isbn=978-1-4020-6671-9 |editor1-last=Aggarwal|editor2-first=Joel R. |editor2-last=Gat|editor3-first= Klaus F. |editor3-last=Froehlich|accessdate=6 May 2012|page=11|chapter=Isotopic Tracers for Obtaining Hydrologic Parameters|url=http://books.google.be/books?id=XKk6V_IeJbIC&lpg=PA11&pg=PA11#v=onepage&q&f=false|editor-first=Pradeep K.}}</ref><ref>{{cite book|last=Rao|first=S. M.|title=Practical isotope hydrology|year=2006|publisher=New India Publishing Agency|location=New Delhi|isbn=978-81-89422-33-2|url=http://books.google.com/?id=E7TVDVVji0EC&lpg=PA11&dq=isotope%20hydrology%20iodine&pg=PA11#v=onepage&q&f=false|accessdate=6 May 2012|pages=12–13|chapter=Radioisotopes of hydrological interest}}</ref><ref>{{cite web|title=Investigating leaks in Dams & Reservoirs|url=http://www.iaea.org/technicalcooperation/documents/sheet20dr.pdf|work=IAEA.org|accessdate=6 May 2012}}</ref><ref>{{cite book|last=Araguás|first=Luis Araguás|title=Detection and prevention of leaks from dams|year=2002|publisher=Taylor & Francis|isbn=978-90-5809-355-4|url=http://books.google.com/?id=FXB-HMzfBnkC&lpg=PA179&pg=PA179#v=onepage&q&f=false|first2=Antonio |last2=Plata Bedmar|accessdate=6 May 2012|pages=179–181|chapter=Artificial radioactive tracers}}</ref>
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| Since late 1940s, radioactive tracers have been used by the oil industry. Tagged at the surface, water is then tracked downhole, using the appropriated gamma detector, to determine flows and detect underground leaks. I-131 has been the most widely used tagging isotope in an aqueous solution of sodium iodine.<ref name="Reis iodine">{{cite book |last1=Reis |first1=John C. |year=1976 |title=Environmental Control in Petroleum Engineering |publisher=Gulf Professional Publishers|isbn=978-0-88415-273-6|page=55|url=http://books.google.com/books?id=XAseQ35m2OYC&lpg=PA55&pg=PA54#v=onepage&q&f=false|chapter=Radioactive materials}}</ref><ref>{{cite book|last=McKinley|first=R. M.|title=Temperature, radioactive tracer, and noise logging for injection well integrity|year=1994|publisher=U.S. Environmental Protection Agency|location=Washington|url=http://www.epa.gov/ogwdw/uic/pdfs/Historical/techguide_uic_temp_tracer__noise_logging_1994.pdf|accessdate=6 May 2012|chapter=Radioactive tracer surveys}}</ref><ref>{{cite web|title=Radioactive-tracer log|url=http://www.glossary.oilfield.slb.com/Display.cfm?Term=radioactive-tracer%20log|work=Schlumberger.com|accessdate=6 May 2012|author=Schlumberger Ltd}}</ref> It is used to characterize the [[hydraulic fracturing]] fluid to help determine the injection profile and location of fractures created by [[hydraulic fracturing]].<ref name="No5635712">{{cite patent |country=US |number=5635712 |status=patent |title=Method for monitoring the hydraulic fracturing of a subterranean formation |pubdate=1997-06-03 |inventor=Scott, George L.}}</ref><ref name="US4415805">{{cite patent |country=US |number=4415805 |status=patent |title=Method and apparatus for evaluating multiple stage fracturing or earth formations surrounding a borehole |pubdate=1983-11-15 |inventor=Fertl, Walter H.}}</ref><ref name="US5441110">{{cite patent |country=US |number=5441110 |status=patent |title=System and method for monitoring fracture growth during hydraulic fracture treatment |pubdate=1995-08-15 |inventor=Scott, George L.}}</ref>
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| ==See also==
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| *[[Iodine]]
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| *[[Isotopes of iodine]]
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| *[[Iodine in biology]]
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| *[[Iodide]]
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| *[[Potassium iodide]]
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| ==References==
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| {{Reflist|30em}}
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| ==External links==
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| *[http://www.ead.anl.gov/pub/doc/iodine.pdf ANL factsheet]
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| *[http://www.radiologyinfo.org/en/info.cfm?pg=radioiodine RadiologyInfo - The radiology information resource for patients: Radioiodine (I -131) Therapy]
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| *[http://www.atsdr.cdc.gov/HEC/CSEM/iodine/index.html Case Studies in Environmental Medicine: Radiation Exposure from Iodine 131]
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| *[http://rsna2004.rsna.org/rsna2004/V2004/conference/event_display.cfm?em_id=4407767 Sensitivity of Personal Homeland Security Radiation Detectors to Medical Radionuclides and Implications for Counseling of Nuclear Medicine Patients]
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| *[http://toxnet.nlm.nih.gov/cgi-bin/sis/search/r?dbs+hsdb:@term+@na+@rel+iodine,+radioactive NLM Hazardous Substances Databank – Iodine, Radioactive]
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| {{Isotope|element=iodine
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| |lighter=<sup>130</sup>I
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| |heavier=<sup>132</sup>I
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| |before=[[Tellurium-131|<sup>131</sup>Te]] '''([[beta decay|β<sup>-</sup>]])
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| |after=[[Xenon-131|<sup>131</sup>Xe]] '''(β<sup>-</sup>)
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| }}
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| {{Use dmy dates|date=March 2011}}
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| {{Radiopharmaceuticals}}
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| {{Therapeutic radiopharmaceuticals}}
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| {{Radiation oncology}}
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| [[Category:Isotopes of iodine]]
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| [[Category:Antithyroid drugs]]
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| [[Category:Fission products]]
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| {{Link FA|de}}
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