{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,28]],"date-time":"2026-10-28T07:36:20Z","timestamp":1793172980524,"version":"4.5.0"},"reference-count":21,"publisher":"IOP Publishing","issue":"20","license":[{"start":{"date-parts":[[2026,10,28]],"date-time":"2026-10-28T00:00:00Z","timestamp":1793145600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,10,28]],"date-time":"2026-10-28T00:00:00Z","timestamp":1793145600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/iopscience.iop.org\/info\/page\/text-and-data-mining"}],"content-domain":{"domain":["iopscience.iop.org"],"crossmark-restriction":false},"short-container-title":["Phys. Med. Biol."],"published-print":{"date-parts":[[2026,10,28]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    <jats:italic>Objective.<\/jats:italic>\n                    No harmonized methodology exists that enables traceable reference dosimetry with EBT4 film. The influence of humidity on EBT4 films is often overlooked and currently under-documented. This study quantified humidity effects for postal audit reference dosimetry and explored the feasibility of empirical correction methods.\n                    <jats:italic>Approach.<\/jats:italic>\n                    EBT4 films mounted in slide-frames were stored in humidity-controlled environments between 0 %RH and 100 %RH and scanned using a slide-scanner. Optical density (\n                    <jats:italic>OD<\/jats:italic>\n                    ) was evaluated as a function of dose and humidity. Humidity darkening, changes in dose response and post irradiation growth were quantified. A humidity response factor,\n                    <jats:italic>\n                      H\n                      <jats:sub>OD<\/jats:sub>\n                    <\/jats:italic>\n                    , was introduced to describe the humidity dependent changes in dose-response. Two film intrinsic proxies were evaluated as possible proxies for the film humidity state.\n                    <jats:italic>Main results.<\/jats:italic>\n                    Humidity was shown to affect\n                    <jats:italic>OD<\/jats:italic>\n                    and the humidity response factor,\n                    <jats:italic>\n                      H\n                      <jats:sub>OD<\/jats:sub>\n                    <\/jats:italic>\n                    . If not accounted for, this can lead to significant dosimetric errors. Between 12 %RH and 68 %RH,\n                    <jats:italic>\n                      H\n                      <jats:sub>OD<\/jats:sub>\n                    <\/jats:italic>\n                    exhibited linear behaviour as did the two film intrinsic proxies. Both humidity darkening and\n                    <jats:italic>\n                      H\n                      <jats:sub>OD<\/jats:sub>\n                    <\/jats:italic>\n                    showed to be reversible within the experimental uncertainty after re-acclimatization at 56 %RH. Exposure to 0 %RH and 100 %RH resulted in response behaviour outside the practical operating range. The use of 0-Gy control films substantially reduced humidity-dependent offsets. The film-intrinsic humidity proxies showed relationships with\n                    <jats:italic>\n                      H\n                      <jats:sub>OD<\/jats:sub>\n                    <\/jats:italic>\n                    within the present single-sheet experiment, but their practical use requires further validation across film-lots and scanners.\n                    <jats:italic>Significance.<\/jats:italic>\n                    This study demonstrates that humidity is a relevant influence quantity for EBT4-based reference dosimetry and should be controlled during film transport and storage. For the VSL postal audit service, humidity is regulated using BOVEDA-49 packages and monitored during transport as a practical mitigation strategy. The proposed correction formalism provides a method to investigate humidity-response behaviour for a specific film-sheet and scanner combination but does not yet constitute a generally validated correction method.\n                  <\/jats:p>","DOI":"10.1088\/1361-6560\/aeafa7","type":"journal-article","created":{"date-parts":[[2026,10,2]],"date-time":"2026-10-02T22:53:24Z","timestamp":1790981604000},"page":"205037","update-policy":"https:\/\/doi.org\/10.1088\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Humidity effects in Gafchromic\n                    <sup>TM<\/sup>\n                    EBT4 films for postal audits: characterization, reversibility and exploration of correction methods"],"prefix":"10.1088","volume":"71","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7470-4356","authenticated-orcid":true,"given":"Leon","family":"de Prez","sequence":"first","affiliation":[{"name":"VSL\u2014National Metrology Institute"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"266","published-online":{"date-parts":[[2026,10,28]]},"reference":[{"key":"pmbaeafa7bib1","doi-asserted-by":"publisher","first-page":"3687","DOI":"10.1118\/1.3455713","type":"journal-article","article-title":"Evaluation of EBT-2 model GAFCHROMICTM film performance in water","volume":"37","author":"Aldelaijan","year":"2010","journal-title":"Med. 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