{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T06:11:06Z","timestamp":1791353466444,"version":"4.3.1"},"reference-count":19,"publisher":"Wiley","issue":"2","license":[{"start":{"date-parts":[[2017,1,30]],"date-time":"2017-01-30T00:00:00Z","timestamp":1485734400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"funder":[{"DOI":"10.13039\/501100000046","name":"National Research Council Canada","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000046","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Medical Physics"],"published-print":{"date-parts":[[2017,2]]},"abstract":"<jats:sec><jats:title>Purpose<\/jats:title><jats:p>International dosimetry protocols require measurements made with a vented ionization chamber to be corrected for the influence of air density by using the standard temperature\u2010pressure correction factor. The effect of humidity, on the other hand, is generally ignored with the provision that the relative humidity (<jats:styled-content style=\"fixed-case\">RH<\/jats:styled-content>) is within certain limits (typically 20% to 80%). However, there is little experimental data in the published literature as to the true effect of humidity on modern reference\u2010class ionization chambers. This investigation used two different radiation beams \u2013 a Co\u201060 irradiator and an Sr\u201090 check source \u2013 to examine the effect of humidity on several Farmer\u2010type ionization chambers.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods<\/jats:title><jats:p>An environmental cabinet controlled the humidity. For the Co\u201060 beam, the irradiation was external, whereas for the Sr\u201090 measurements, the source itself was placed within the cabinet. Extensive measurements were carried out to ensure that the experimental setup provided reproducible readings. Four chamber types were investigated: <jats:styled-content style=\"fixed-case\">IBA FC<\/jats:styled-content>65\u2010G, <jats:styled-content style=\"fixed-case\">IBA FC<\/jats:styled-content>65\u2010P, <jats:styled-content style=\"fixed-case\">PTW<\/jats:styled-content> 30013 and Exradin A19. The different wall materials provided potentially different mechanical responses (i.e., in terms of expansion\/contraction) to the water content in the air. The relative humidity was varied between 8% and 98% and measurements were made with both increasing and decreasing humidity to investigate any possible hysteresis effects.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>Measurements in Co\u201060 were consistent with the published data obtained with primary standard cavity chambers in <jats:styled-content style=\"fixed-case\">ICRU<\/jats:styled-content> Report 31 (i.e., a very small variation &lt;0.1% for <jats:styled-content style=\"fixed-case\">RH<\/jats:styled-content> &gt;10%). The measurements in the Sr\u201090 field showed no dependence with the relative humidity, within the measurement uncertainties (0.05%, k = 1). Very good repeatability of the ionization current was obtained over successive wet\/dry cycles, no hysteresis was observed, and there was no dependence on chamber type.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>These results indicate that humidity has no significant effect on these particular types of ionization chambers, consistent with recommendations in current megavoltage dosimetry protocols.<\/jats:p><\/jats:sec>","DOI":"10.1002\/mp.12057","type":"journal-article","created":{"date-parts":[[2016,12,10]],"date-time":"2016-12-10T20:02:58Z","timestamp":1481400178000},"page":"694-702","source":"Crossref","is-referenced-by-count":14,"title":["Examining the influence of humidity on reference ionization chamber performance"],"prefix":"10.1002","volume":"44","author":[{"given":"Malcolm R.","family":"McEwen","sequence":"first","affiliation":[{"name":"Ionizing Radiation Standards National Research Council Canada Ottawa Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jaswinder","family":"Taank","sequence":"additional","affiliation":[{"name":"Department of Medical Physics and Applied Radiation Sciences McMaster University Hamilton Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2017,1,30]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.596292"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.598691"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.4866223"},{"key":"e_1_2_9_5_1","unstructured":"IAEA (International Atomic Energy Agency).Absorbed dose determination in external beam radiotherapy(IAEA Technical Reports Series No. 398) (Vienna:IAEA)2000"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1088\/0031-9155\/48\/18\/301"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1088\/0031-9155\/51\/19\/017"},{"key":"e_1_2_9_8_1","first-page":"1650","article-title":"Etude experimentale de l'influence de la vapeur d'eau sur l'ionisation produite dans l'air","volume":"268","author":"Niatel MT","year":"1969","journal-title":"C R Acad Sci Paris"},{"key":"e_1_2_9_9_1","first-page":"361","article-title":"Influence de la vapeur d'eau sur l'ionisation de l'air dans le cas d'une chambre a cavite","volume":"281","author":"Niatel MT","year":"1975","journal-title":"C R Acad Sci Paris"},{"key":"e_1_2_9_10_1","unstructured":"HofmeesterG H SommerwilA.Report CCEMRI(I) 77\u201022 bureau international des poids et mesure: s\u00e8vres1977."},{"key":"e_1_2_9_11_1","volume-title":"Average energy required to produce an ion pair, ICRU Report No. 31","author":"ICRU (International Commission on Radiation Units)","year":"1979"},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.1088\/0031-9155\/49\/10\/013"},{"key":"e_1_2_9_13_1","volume-title":"Effect of humidity on measurements with a well type chamber","author":"IAEA Dosimetry and Medical Radiation Physics Section","year":"2001"},{"key":"e_1_2_9_14_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.596292"},{"key":"e_1_2_9_15_1","doi-asserted-by":"publisher","DOI":"10.1088\/0031-9155\/37\/1\/022"},{"key":"e_1_2_9_16_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.1644520"},{"key":"e_1_2_9_17_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.598226"},{"key":"e_1_2_9_18_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.4924518"},{"key":"e_1_2_9_19_1","doi-asserted-by":"publisher","DOI":"10.1118\/1.595683"},{"key":"e_1_2_9_20_1","unstructured":"Joint Committee for Guides in Metrology (JCGM) Report 100: Evaluation of measurement data \u2013 Guide to the expression of uncertainty in measurement (ISO\/IEC Guide 98\u20103) http:\/\/www.iso.org\/sites\/JCGM\/JCGM-introduction.htm2008."}],"container-title":["Medical Physics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fmp.12057","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/aapm.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/mp.12057","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,9,15]],"date-time":"2023-09-15T10:35:19Z","timestamp":1694774119000},"score":1,"resource":{"primary":{"URL":"https:\/\/aapm.onlinelibrary.wiley.com\/doi\/10.1002\/mp.12057"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,1,30]]},"references-count":19,"journal-issue":{"issue":"2","published-print":{"date-parts":[[2017,2]]}},"alternative-id":["10.1002\/mp.12057"],"URL":"https:\/\/doi.org\/10.1002\/mp.12057","archive":["Portico"],"relation":{},"ISSN":["0094-2405","2473-4209"],"issn-type":[{"value":"0094-2405","type":"print"},{"value":"2473-4209","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,1,30]]}}}