Flight-time equivalent dose

{{Short description|Dose measurement of radiation}} {{For other uses|Flight Time (disambiguation){{!}}Flight Time}}

'''Flight-time equivalent dose''' (FED) is an informal unit of measurement of [[ionizing radiation]] exposure. Expressed in units of flight-time (i.e., flight-seconds, flight-minutes, flight-hours), one unit of flight-time is approximately equivalent to the radiological dose received during the same unit of time spent in an [[airliner]] at [[cruising altitude]]. FED is intended as a general educational unit to enable a better understanding of radiological dose by converting dose typically presented in [[sievert]]s into units of time. FED is only meant as an educational exercise and is not a formally adopted dose measurement.

[[File:Radiological exposure from daily life.png|thumb|Visual comparison of radiological exposure from daily life activities.]] [[File:Radiological exposure from medical sources.png|thumb|Visual comparison of radiological exposure from medical sources.]]

==History== The flight-time equivalent dose concept is the creation of Ulf Stahmer, a [[Canadians|Canadian]] [[Professional Engineers Ontario|professional engineer]] working in the field of radioactive materials transport. It was first presented in the poster session<ref>Stahmer, U. 11 – 16 September 2016. [https://www.researchgate.net/publication/308628378_Flight-Time_Equivalent_Dose_-_A_Concept_to_Contextualize_Radiological_Dose Flight-Time Equivalent Dose - A Concept to Contextualize Radiological Dose]. 18th International Symposium of the Packaging and Transport of Radioactive Materials (PATRAM). Kobe, Hyogo, Japan.</ref> at the 18th International Symposium of the Packaging and Transport of Radioactive Materials (PATRAM) held in [[Kobe]], [[Hyōgo Prefecture|Hyogo]], [[Japan]] where the poster received an Aoki Award for distinguished poster presentation.<ref>Nuclear Waste Management Organization (2016). [https://www.nwmo.ca/en/More-information/News-and-Activities/2016/11/17/11/05/NWMO-Engineer-Wins-Award-for-Best-Poster Engineer Wins Award for Best Poster]. Retrieved 10 December 2021.</ref> In 2018, an article on FED<ref>{{cite journal |title=Using Flight-Time to Contextualize Radiological Dose |journal=The Physics Teacher |date=2018-10-24 |last=Stahmer |first=U. |volume=56 |issue=8 |pages=508–511 |doi=10.1119/1.5064556 |s2cid=125730267 |doi-access=free }}</ref> appeared in the peer-reviewed journal [[The Physics Teacher]].

==Usage== Flight-time equivalent dose is an informal measurement, so any equivalences are necessarily approximate. It has been found useful to provide context between radiological doses received from various every-day activities and medical procedures.

==Dose calculation== FED corresponds to the time spent in an airliner flying at altitude required to receive a corresponding radiological dose. FED is calculated by taking a known dose (typically in millisieverts) and dividing it by the average [[dose rate]] (typically in millisieverts per hour) at an altitude of 10,000 m, a typical cruising altitude for a commercial airliner.<br> :<math>FED= \frac{{mSv}_{dose}}{{0.004 \frac{mSv}{h}}_{cruising altitude}}</math> While radiological dose at cruising altitudes varies with [[latitude]], for FED calculations, the radiological [[dose rate]] at an altitude of 10,000 m has been standardized to be 0.004 mSv/h,<ref name = "Friedberg">Friedberg, W; Copeland K (2011). [https://rosap.ntl.bts.gov/view/dot/20607 "Ionizing Radiation in Earth's Atmosphere and in Space Near Earth"] Civil Aerospace Medical Institute, Federal Aviation Administration, DOT/FAA/AM- 11/9.</ref> about 15 times greater than the average dose rate at the [[Earth]]'s surface. Using this technique, the FED received from a 0.01 mSv panoramic dental [[x-ray]] is approximately equivalent to 2.5 flight-hours; the FED received from eating one [[banana]] is approximately equal to 1.5 flight-minutes; and the FED received each year from naturally occurring [[background radiation]] (2.4 mSv/year<ref name = "Grasty">{{cite journal |title=The annual effective dose from natural sources of ionising radiation in Canada |journal=Radiation Protection Dosimetry |date=2004-02-01 |last1=Grasty |first1=R.L. |last2=LaMarre |first2=J.R. |volume=108 |issue=3 |pages=215–226 |doi=10.1093/rpd/nch022 |pmid=15031443 |url=https://academic.oup.com/rpd/article-abstract/108/3/215/1593937?redirectedFrom=fulltext |accessdate=2022-04-28 |url-access=subscription }}</ref>) is approximately equivalent to 600 flight-hours.

==Radiological exposures and limits==

For comparison, a list of activities (including common medical procedures) and their estimated radiological exposures are tabulated below. Regulatory occupational dose limits for the public and radiation workers are also included. Items on this list are represented pictorially in the accompanying illustrations.

{| class="wikitable sortable" |+ List of radiological exposures from various sources |- ! Activity !! Event Type !! Dose !! FED |- | Airport backscatter x-ray [[Full body scanner|full body scan]] || singular || 0.00001 mSv<ref>{{Cite web |url= https://www.aapm.org/pubs/reports/RPT_217.pdf |title=AAPM Report No. 217 Radiation Dose from Airport Scanners|date=June 2013 |website=American Association of Physicists in Medicine |access-date=26 April 2022 }}</ref> || 9 flight-seconds |- | One hour of [[Health effects of sunlight exposure|sun exposure]] || singular || 0.00004 mSv<ref name = "Grasty" /> || 36 flight-seconds |- | Household [[smoke detector]] || annual || 0.00008 mSv<ref name="epa">{{cite web |url=https://www.epa.gov/radiation/calculate-your-radiation-dose |title=Calculate your radiation dose |date=3 October 2014 |publisher=United States Environmental Protection Agency |accessdate=2022-04-26 }}</ref> || 1.2 flight-minutes |- | Living near a [[Nuclear power plant|nuclear generating station]] || annual || 0.00009 mSv<ref name="epa" /> || 1.3 flight-minutes |- | Eating one banana || singular || 0.0001 mSv<ref>{{cite web |url=http://health.phys.iit.edu/extended_archive/9503/msg00074.html |title=Banana Equivalent Dose |last=Mansfield |first=G. |publisher=RadSafe -- The International Radiation Protection (Health Physics) Mailing List |date=1995-03-08 |accessdate=2022-04-28 }}</ref> || 1.5 flight-minutes |- | Living near a [[Fossil fuel power station|coal generating station]] || annual || 0.0003 mSv<ref name="epa" /> || 4.5 flight-minutes |- | Crowns or [[Dentures|false teeth]] || annual || 0.0007 mSv<ref name="epa" /> || 10.5 flight-minutes |- | [[Bone scan]] or extremity (arm) x-ray || singular || 0.001 mSv<ref name="Mettler">{{cite journal |title=Effective Doses in Radiology and Diagnostic Nuclear Medicine: A Catalog |journal=Radiology |year=2008 |last1=Mettler |first1=F.A. |last2=Huda |first2=W. |last3=Yoshizumi |first3=T.T. |last4=Mahesh |first4=M. |volume=248 |issue=1 |pages=254–63 |doi=10.1148/radiol.2481071451 |pmid=18566177 }}</ref> || 15 flight-minutes |- | '''One hour of air travel''' || singular || 0.004 mSv<ref name="Friedberg" /><ref name="Reitz">{{cite journal |title=Radiation Environment in the Stratosphere |journal=Radiation Protection Dosimetry |date=1993-05-01 |last=Reitz |first=G. |volume=48 |issue=1 |pages=5–29 |doi=10.1093/oxfordjournals.rpd.a081837 |url=https://academic.oup.com/rpd/article-abstract/48/1/5/1611190 |accessdate=2022-04-28 |url-access=subscription }}</ref><ref name="Shea">{{cite conference |last1=Shea |first1=M.A. |last2=Smart |first2=D.F. |title=Comment on Galactic Radiation Dose to Air Crews |url=https://ui.adsabs.harvard.edu/abs/2001ICRC...10.4071S/abstract |conference=27th International Cosmic Ray Conference |date=August 2001 |bibcode=2001ICRC...10.4071S }}</ref><ref name="Bennett">{{cite journal |title=A Survey of the Cosmic Radiation Exposure of Air Canada Pilots during Maximum Galactic Radiation Conditions in 2009 |journal=Radiation Measurements |year=2013 |last1=Bennett |first1=L.G.I. |last2=Lewis |first2=B.J. |last3=Bennett |first3=M.J. |last4=McCall |first4=M.J. |last5=Bean |first5=M |volume=49 |issue=1 |pages=103–108 |doi=10.1016/j.radmeas.2012.12.004 |url=https://www.sciencedirect.com/science/article/abs/pii/S1350448712003538 |accessdate=2022-04-28 |url-access=subscription }}</ref> || 1 flight-hour |- | Dental (intraoral) or knee x-ray || singular || 0.005 mSv<ref name="Mettler"/> || 1.2 flight-hours |- | Dental (panoramic) or shoulder x-ray || singular || 0.01 mSv<ref name="Mettler"/> || 2.5 flight-hours |- | Sleeping next to someone || annual || 0.02 mSv<ref>{{cite web |url=http://www.slideshare.net/leishmanassociates/human-health-and-the-biological-effects-of-tritium-in-drinking-water-boreham |title=Human health and the biological effects of tritium in drinking water |last=Borham |first=D. |work=Slide 16 |date=27 October 2010 |accessdate=2022-04-26 }}</ref> || 5 flight-hours |- | Bone scan with [[CT scan|CT]] || singular || 0.04 mSv<ref name="Mettler"/> || 10 flight-hours |- | Living in a stone or brick building || annual || 0.07 mSv<ref name="epa" /> || 17.5 flight-hours |- | Chest or skull x-ray || singular || 0.1 mSv<ref name="Mettler"/> || 25 flight-hours |- | Smoking [[cigarette]]s (1 cigarette per day) || annual || 0.018 mSv<ref>{{Cite web|url= https://ncrponline.org/shop/reports/report-no-160-ionizing-radiation-exposure-of-the-population-of-the-united-states|title=Report No. 160 – Ionizing Radiation Exposure of the Population of the United States|date=3 March 2009|website=National Council on Radiation Protection and Measurements|access-date=26 April 2022 }}</ref> || 4.5 flight-hours |- | Cervical spine x-ray || singular || 0.2 mSv<ref name="Mettler"/> || 50 flight-hours |- | [[Mammography|Mammogram]] || singular || 0.4 mSv<ref name="Mettler"/> || 100 flight-hours |- | Pelvic x-ray || singular || 0.6 mSv<ref name="Mettler"/> || 150 flight-hours |- | Abdomen or hip x-ray || singular || 0.7 mSv<ref name="Mettler"/> || 175 flight-hours |- | Public dose limit || limit || 1 mSv<ref name="RPR">{{cite web|title=Dose limits|first1= International Commission on Radiological Protection|last1= ICRP|url=https://icrpaedia.org/Dose_limits|website=ICRPedia|publisher=ICRP|access-date=26 April 2022}}</ref> || 250 flight-hours |- | Lumbar spine x-ray || singular || 1.5 mSv<ref name="Mettler"/> || 375 flight-hours |- | Background radiation in [[Toronto]], CA || annual || 1.6 mSv<ref name = "Grasty" /> || 400 flight-hours |- | Brain CT scan || singular || 2 mSv<ref name="Mettler"/> || 500 flight-hours |- | Background radiation - worldwide average || annual || 2.4 mSv<ref name = "Grasty" /> || 600 flight-hours |- | '''Flight crew''' || annual || 3 mSv<ref name = "Friedberg" /><ref name="Reitz" /><ref name="Shea" /><ref name="Bennett" /><ref>{{cite journal |title=Air crew radiation exposure – An overview |journal=Nuclear News |year=2000 |last=Bailey |first=S. |volume=43 |issue=1 |pages=32–40 |url=http://www3.ans.org/pubs/magazines/nn/pdfs/2000-1-3.pdf |accessdate=2022-04-26 }}</ref> || 750 flight-hours |- | Neck CT or calcium scoring CT || singular || 3 mSv<ref name="Mettler"/> || 750 flight-hours |- | Background radiation in [[Winnipeg]], CA || annual || 4 mSv<ref name = "Grasty" /> || 1000 flight-hours |- | Thoracic [[angiography]] of heart || singular || 5 mSv<ref name="Mettler"/> || 1250 flight-hours |- | Pelvic or chest CT scan || singular || 6 mSv<ref name="Mettler"/> || 1500 flight-hours |- | Barium [[enema]] || singular || 8 mSv<ref name="Mettler"/> || 2000 flight-hours |- | Average [[Fukushima nuclear disaster|Fukishima]] recovery worker || singular || 12 mSv<ref>{{cite book |last=United Nations Environment Programme |url=https://www.un-ilibrary.org/content/books/9789210599597 |title=Radiation Effects and Sources |edition= |publisher=United Nations Environment Programme |year=2016 |doi=10.18356/b1749f17-en |isbn=9789210599597 }}</ref> || 3000 flight-hours |- | Abdominal angiography or [[aortography]] || singular || 12 mSv<ref name="Mettler"/> || 3000 flight-hours |- | Coronary angioplasty or [[stent]] placement || singular || 15 mSv<ref name="Mettler"/> || 3750 flight-hours |- | Coronary angiography || singular || 16 mSv<ref name="Mettler"/> || 4000 flight-hours |- | Average annual radiation worker dose limit || limit || 20 mSv<ref>{{cite web |title=Directive 2013/59/Euratom - protection against ionising radiation |url=https://osha.europa.eu/en/legislation/directives/directive-2013-59-euratom-protection-against-ionising-radiation |website=European Agency For Safety And Health At Work |access-date=26 April 2024}}</ref> || 5000 flight-hours |- | Maximum annual radiation worker dose limit || limit || 50 mSv<ref name="RPR" /> || 12,500 flight-hours |- | Pelvic vein [[embolization]] || singular || 60 mSv<ref name="Mettler"/> || 15,000 flight-hours |- | Transjugular intrahepatic portosystemic [[Shunt (medical)|shunt]] placement || singular || 70 mSv<ref name="Mettler"/> || 17,500 flight-hours |- | Astronaut on 6 month [[International Space Station|ISS]] mission || singular || 72 mSv<ref>{{Cite web |url= https://ntrs.nasa.gov/api/citations/20070010704/downloads/20070010704.pdf |title=Space Radiation Organ Doses for Astronauts on Past and Future Missions|last=Cucinotta |first=F.A.|date=January 1, 2007 |website=NASA Technical Reports Server |access-date=26 April 2022 }}</ref> || 18,000 flight-hours |- | Lowest acute dose known to cause [[cancer]] || singular || 100 mSv<ref>{{cite web |url=http://nuclearsafety.gc.ca/eng/resources/radiation/introduction-to-radiation/radiation-health-effects.cfm |title=Radiation Health Effects |date=3 February 2014 |publisher=Canadian Nuclear Safety Commission |accessdate=2022-04-26 |quote=However, studies to date have not been able to show any excess cancers or other diseases in people chronically exposed to radiation at doses lower than about 100 mSv. }}</ref><ref>{{cite web |url=https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/bio-effects-radiation.html |title=Backgrounder on Biological Effects of Radiation |work=Biological Effects of Radiation |publisher=United States Nuclear Regulatory Commission |date=2020-07-08 |accessdate=2022-04-28 |quote=The data show high doses of radiation may cause cancers. But there are no data to establish a firm link between cancer and doses below about 10,000 mrem (100 mSv – 100 times the NRC limit). }}</ref> || 25,000 flight-hours |}

==See also== * [[Background radiation]] * [[Background radiation equivalent time]] * [[Banana equivalent dose]] * [[List of unusual units of measurement]]

== References ==

{{reflist}}

[[Category:Radioactivity quantities]] [[Category:Background radiation]] [[Category:Equivalent units]]