# Flight-time equivalent dose

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Dose measurement of radiation

For other uses, see [Flight Time](/source/Flight_Time_(disambiguation)).

**Flight-time equivalent dose** (FED) is an informal unit of measurement of [ionizing radiation](/source/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](/source/Airliner) at [cruising altitude](/source/Cruising_altitude). FED is intended as a general educational unit to enable a better understanding of radiological dose by converting dose typically presented in [sieverts](/source/Sievert) into units of time. FED is only meant as an educational exercise and is not a formally adopted dose measurement.

Visual comparison of radiological exposure from daily life activities.

Visual comparison of radiological exposure from medical sources.

## History

The flight-time equivalent dose concept is the creation of Ulf Stahmer, a [Canadian](/source/Canadians) [professional engineer](/source/Professional_Engineers_Ontario) working in the field of radioactive materials transport. It was first presented in the poster session[1] at the 18th International Symposium of the Packaging and Transport of Radioactive Materials (PATRAM) held in [Kobe](/source/Kobe), [Hyogo](/source/Hy%C5%8Dgo_Prefecture), [Japan](/source/Japan) where the poster received an Aoki Award for distinguished poster presentation.[2] In 2018, an article on FED[3] appeared in the peer-reviewed journal [The Physics Teacher](/source/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](/source/Dose_rate) (typically in millisieverts per hour) at an altitude of 10,000 m, a typical cruising altitude for a commercial airliner.

- F E D = m S v d o s e 0.004 m S v h c r u i s i n g a l t i t u d e {\displaystyle FED={\frac {{mSv}_{dose}}{{0.004{\frac {mSv}{h}}}_{cruisingaltitude}}}}

While radiological dose at cruising altitudes varies with [latitude](/source/Latitude), for FED calculations, the radiological [dose rate](/source/Dose_rate) at an altitude of 10,000 m has been standardized to be 0.004 mSv/h,[4] about 15 times greater than the average dose rate at the [Earth](/source/Earth)'s surface. Using this technique, the FED received from a 0.01 mSv panoramic dental [x-ray](/source/X-ray) is approximately equivalent to 2.5 flight-hours; the FED received from eating one [banana](/source/Banana) is approximately equal to 1.5 flight-minutes; and the FED received each year from naturally occurring [background radiation](/source/Background_radiation) (2.4 mSv/year[5]) 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.

List of radiological exposures from various sources Activity Event Type Dose FED Airport backscatter x-ray full body scan singular 0.00001 mSv[6] 9 flight-seconds One hour of sun exposure singular 0.00004 mSv[5] 36 flight-seconds Household smoke detector annual 0.00008 mSv[7] 1.2 flight-minutes Living near a nuclear generating station annual 0.00009 mSv[7] 1.3 flight-minutes Eating one banana singular 0.0001 mSv[8] 1.5 flight-minutes Living near a coal generating station annual 0.0003 mSv[7] 4.5 flight-minutes Crowns or false teeth annual 0.0007 mSv[7] 10.5 flight-minutes Bone scan or extremity (arm) x-ray singular 0.001 mSv[9] 15 flight-minutes One hour of air travel singular 0.004 mSv[4][10][11][12] 1 flight-hour Dental (intraoral) or knee x-ray singular 0.005 mSv[9] 1.2 flight-hours Dental (panoramic) or shoulder x-ray singular 0.01 mSv[9] 2.5 flight-hours Sleeping next to someone annual 0.02 mSv[13] 5 flight-hours Bone scan with CT singular 0.04 mSv[9] 10 flight-hours Living in a stone or brick building annual 0.07 mSv[7] 17.5 flight-hours Chest or skull x-ray singular 0.1 mSv[9] 25 flight-hours Smoking cigarettes (1 cigarette per day) annual 0.018 mSv[14] 4.5 flight-hours Cervical spine x-ray singular 0.2 mSv[9] 50 flight-hours Mammogram singular 0.4 mSv[9] 100 flight-hours Pelvic x-ray singular 0.6 mSv[9] 150 flight-hours Abdomen or hip x-ray singular 0.7 mSv[9] 175 flight-hours Public dose limit limit 1 mSv[15] 250 flight-hours Lumbar spine x-ray singular 1.5 mSv[9] 375 flight-hours Background radiation in Toronto, CA annual 1.6 mSv[5] 400 flight-hours Brain CT scan singular 2 mSv[9] 500 flight-hours Background radiation - worldwide average annual 2.4 mSv[5] 600 flight-hours Flight crew annual 3 mSv[4][10][11][12][16] 750 flight-hours Neck CT or calcium scoring CT singular 3 mSv[9] 750 flight-hours Background radiation in Winnipeg, CA annual 4 mSv[5] 1000 flight-hours Thoracic angiography of heart singular 5 mSv[9] 1250 flight-hours Pelvic or chest CT scan singular 6 mSv[9] 1500 flight-hours Barium enema singular 8 mSv[9] 2000 flight-hours Average Fukishima recovery worker singular 12 mSv[17] 3000 flight-hours Abdominal angiography or aortography singular 12 mSv[9] 3000 flight-hours Coronary angioplasty or stent placement singular 15 mSv[9] 3750 flight-hours Coronary angiography singular 16 mSv[9] 4000 flight-hours Average annual radiation worker dose limit limit 20 mSv[18] 5000 flight-hours Maximum annual radiation worker dose limit limit 50 mSv[15] 12,500 flight-hours Pelvic vein embolization singular 60 mSv[9] 15,000 flight-hours Transjugular intrahepatic portosystemic shunt placement singular 70 mSv[9] 17,500 flight-hours Astronaut on 6 month ISS mission singular 72 mSv[19] 18,000 flight-hours Lowest acute dose known to cause cancer singular 100 mSv[20][21] 25,000 flight-hours

## See also

- [Background radiation](/source/Background_radiation)

- [Background radiation equivalent time](/source/Background_radiation_equivalent_time)

- [Banana equivalent dose](/source/Banana_equivalent_dose)

- [List of unusual units of measurement](/source/List_of_unusual_units_of_measurement)

## References

1. **[^](#cite_ref-1)** Stahmer, U. 11 – 16 September 2016. [Flight-Time Equivalent Dose - A Concept to Contextualize Radiological Dose](https://www.researchgate.net/publication/308628378_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.

1. **[^](#cite_ref-2)** Nuclear Waste Management Organization (2016). [Engineer Wins Award for Best Poster](https://www.nwmo.ca/en/More-information/News-and-Activities/2016/11/17/11/05/NWMO-Engineer-Wins-Award-for-Best-Poster). Retrieved 10 December 2021.

1. **[^](#cite_ref-3)** Stahmer, U. (2018-10-24). ["Using Flight-Time to Contextualize Radiological Dose"](https://doi.org/10.1119%2F1.5064556). *The Physics Teacher*. **56** (8): 508–511. [doi](/source/Doi_(identifier)):[10.1119/1.5064556](https://doi.org/10.1119%2F1.5064556). [S2CID](/source/S2CID_(identifier)) [125730267](https://api.semanticscholar.org/CorpusID:125730267).

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1. ^ [***a***](#cite_ref-Mettler_9-0) [***b***](#cite_ref-Mettler_9-1) [***c***](#cite_ref-Mettler_9-2) [***d***](#cite_ref-Mettler_9-3) [***e***](#cite_ref-Mettler_9-4) [***f***](#cite_ref-Mettler_9-5) [***g***](#cite_ref-Mettler_9-6) [***h***](#cite_ref-Mettler_9-7) [***i***](#cite_ref-Mettler_9-8) [***j***](#cite_ref-Mettler_9-9) [***k***](#cite_ref-Mettler_9-10) [***l***](#cite_ref-Mettler_9-11) [***m***](#cite_ref-Mettler_9-12) [***n***](#cite_ref-Mettler_9-13) [***o***](#cite_ref-Mettler_9-14) [***p***](#cite_ref-Mettler_9-15) [***q***](#cite_ref-Mettler_9-16) [***r***](#cite_ref-Mettler_9-17) [***s***](#cite_ref-Mettler_9-18) [***t***](#cite_ref-Mettler_9-19) Mettler, F.A.; Huda, W.; Yoshizumi, T.T.; Mahesh, M. (2008). "Effective Doses in Radiology and Diagnostic Nuclear Medicine: A Catalog". *Radiology*. **248** (1): 254–63. [doi](/source/Doi_(identifier)):[10.1148/radiol.2481071451](https://doi.org/10.1148%2Fradiol.2481071451). [PMID](/source/PMID_(identifier)) [18566177](https://pubmed.ncbi.nlm.nih.gov/18566177).

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1. ^ [***a***](#cite_ref-RPR_15-0) [***b***](#cite_ref-RPR_15-1) ICRP, International Commission on Radiological Protection. ["Dose limits"](https://icrpaedia.org/Dose_limits). *ICRPedia*. ICRP. Retrieved 26 April 2022.

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1. **[^](#cite_ref-20)** ["Radiation Health Effects"](http://nuclearsafety.gc.ca/eng/resources/radiation/introduction-to-radiation/radiation-health-effects.cfm). Canadian Nuclear Safety Commission. 3 February 2014. Retrieved 2022-04-26. 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.

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Adapted from the Wikipedia article [Flight-time equivalent dose](https://en.wikipedia.org/wiki/Flight-time_equivalent_dose) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Flight-time_equivalent_dose?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.