Flight-time equivalent dose

Last updated

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 sieverts into units of time. FED is only meant as an educational exercise and is not a formally adopted dose measurement.

Contents

Visual comparison of radiological exposure from daily life activities. Radiological exposure from daily life.png
Visual comparison of radiological exposure from daily life activities.
Visual comparison of radiological exposure from medical sources. Radiological exposure from medical sources.png
Visual comparison of radiological exposure from medical sources.

History

The flight-time equivalent dose concept is the creation of Ulf Stahmer, a Canadian professional engineer 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, Hyogo, 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.

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.

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, [4] 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 [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 radiologial exposures from various sources
ActivityEvent TypeDoseFED
Airport x-ray full body scan singular0.00001 mSv [6] 9 flight-seconds
One hour of sun exposure singular0.00004 mSv [5] 36 flight-seconds
Household smoke detector annual0.00008 mSv [7] 1.2 flight-minutes
Living near a nuclear generating station annual0.00009 mSv [7] 1.3 flight-minutes
Eating one bananasingular0.0001 mSv [8] 1.5 flight-minutes
Living near a coal generating station annual0.0003 mSv [7] 4.5 flight-minutes
Crowns or false teeth annual0.0007 mSv [7] 10.5 flight-minutes
Bone scan or extremity (arm) x-raysingular0.001 mSv [9] 15 flight-minutes
One hour of air travelsingular0.004 mSv [4] [10] [11] [12] 1 flight-hour
Dental (intraoral) or knee x-raysingular0.005 mSv [9] 1.2 flight-hours
Dental (panoramic) or shoulder x-raysingular0.01 mSv [9] 2.5 flight-hours
Sleeping next to someoneannual0.02 mSv [13] 5 flight-hours
Bone scan with CT singular0.04 mSv [9] 10 flight-hours
Living in a stone or brick buildingannual0.07 mSv [7] 17.5 flight-hours
Chest or skull x-raysingular0.1 mSv [9] 25 flight-hours
Smoking cigarettes (1/2 pack per day)annual0.18 mSv [14] 45 flight-hours
Cervical spine x-raysingular0.2 mSv [9] 50 flight-hours
Mammogram singular0.4 mSv [9] 100 flight-hours
Pelvic x-raysingular0.6 mSv [9] 150 flight-hours
Abdomen or hip x-raysingular0.7 mSv [9] 175 flight-hours
Public dose limitlimit1 mSv [15] 250 flight-hours
Lumbar spine x-raysingular1.5 mSv [9] 375 flight-hours
Background radiation in Toronto, CAannual1.6 mSv [5] 400 flight-hours
Brain CT scansingular2 mSv [9] 500 flight-hours
Background radiation - worldwide averageannual2.4 mSv [5] 600 flight-hours
Flight crewannual3 mSv [4] [10] [11] [12] [16] 750 flight-hours
Neck CT or calcium scoring CTsingular3 mSv [9] 750 flight-hours
Background radiation in Winnipeg, CAannual4 mSv [5] 1000 flight-hours
Thoracic angiography of heartsingular5 mSv [9] 1250 flight-hours
Pelvic or chest CT scansingular6 mSv [9] 1500 flight-hours
Barium enema singular8 mSv [9] 2000 flight-hours
Average Fukishima recovery workersingular12 mSv [17] 3000 flight-hours
Abdominal angiography or aortography singular12 mSv [9] 3000 flight-hours
Coronary angioplasty or stent placementsingular15 mSv [9] 3750 flight-hours
Coronary angiographysingular16 mSv [9] 4000 flight-hours
Radiation worker dose limitlimit50 mSv [15] 12,500 flight-hours
Pelvic vein embolization singular60 mSv [9] 15,000 flight-hours
Transjugular intrahepatic portosystemic shunt placementsingular70 mSv [9] 17,500 flight-hours
Astronaut on 6 month ISS missionsingular72 mSv [18] 18,000 flight-hours
Lowest acute dose known to cause cancer singular100 mSv [19] [20] 25,000 flight-hours

See also

Related Research Articles

Background radiation is a measure of the level of ionizing radiation present in the environment at a particular location which is not due to deliberate introduction of radiation sources.

<span class="mw-page-title-main">Acute radiation syndrome</span> Health problems caused by exposure to high levels of ionizing radiation

Acute radiation syndrome (ARS), also known as radiation sickness or radiation poisoning, is a collection of health effects that are caused by being exposed to high amounts of ionizing radiation in a short period of time. Symptoms can start within an hour of exposure, and can last for several months. Early symptoms are usually nausea, vomiting and loss of appetite. In the following hours or weeks, initial symptoms may appear to improve, before the development of additional symptoms, after which either recovery or death follow.

<span class="mw-page-title-main">Sievert</span> SI unit of equivalent dose of ionizing radiation

The sievert is a unit in the International System of Units (SI) intended to represent the stochastic health risk of ionizing radiation, which is defined as the probability of causing radiation-induced cancer and genetic damage. The sievert is important in dosimetry and radiation protection. It is named after Rolf Maximilian Sievert, a Swedish medical physicist renowned for work on radiation dose measurement and research into the biological effects of radiation.

Ionizing radiation, including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel up to 99% of the speed of light, and the electromagnetic waves are on the high-energy portion of the electromagnetic spectrum.

The gray is the unit of ionizing radiation dose in the International System of Units (SI), defined as the absorption of one joule of radiation energy per kilogram of matter.

Radiation dosimetry in the fields of health physics and radiation protection is the measurement, calculation and assessment of the ionizing radiation dose absorbed by an object, usually the human body. This applies both internally, due to ingested or inhaled radioactive substances, or externally due to irradiation by sources of radiation.

Equivalent dose is a dose quantity H representing the stochastic health effects of low levels of ionizing radiation on the human body which represents the probability of radiation-induced cancer and genetic damage. It is derived from the physical quantity absorbed dose, but also takes into account the biological effectiveness of the radiation, which is dependent on the radiation type and energy. In the SI system of units, the unit of measure is the sievert (Sv).

<span class="mw-page-title-main">Health physics</span>

Health physics, also referred to as the science of radiation protection, is the profession devoted to protecting people and their environment from potential radiation hazards, while making it possible to enjoy the beneficial uses of radiation. Health physicists normally require a four-year bachelor’s degree and qualifying experience that demonstrates a professional knowledge of the theory and application of radiation protection principles and closely related sciences. Health physicists principally work at facilities where radionuclides or other sources of ionizing radiation are used or produced; these include research, industry, education, medical facilities, nuclear power, military, environmental protection, enforcement of government regulations, and decontamination and decommissioning—the combination of education and experience for health physicists depends on the specific field in which the health physicist is engaged.

The roentgen equivalent man (rem) is a CGS unit of equivalent dose, effective dose, and committed dose, which are dose measures used to estimate potential health effects of low levels of ionizing radiation on the human body.

Absorbed dose is a dose quantity which is the measure of the energy deposited in matter by ionizing radiation per unit mass. Absorbed dose is used in the calculation of dose uptake in living tissue in both radiation protection, and radiology. It is also used to directly compare the effect of radiation on inanimate matter such as in radiation hardening.

In radiation physics, kerma is an acronym for "kinetic energy released per unit mass", defined as the sum of the initial kinetic energies of all the charged particles liberated by uncharged ionizing radiation in a sample of matter, divided by the mass of the sample. It is defined by the quotient .

<span class="mw-page-title-main">Rolf Maximilian Sievert</span> Swedish medical physicist, professor

Rolf Maximilian Sievert was a Swedish medical physicist whose major contribution was in the study of the biological effects of ionizing radiation.

The rad is a unit of absorbed radiation dose, defined as 1 rad = 0.01 Gy = 0.01 J/kg. It was originally defined in CGS units in 1953 as the dose causing 100 ergs of energy to be absorbed by one gram of matter. The material absorbing the radiation can be human tissue or silicon microchips or any other medium.

Background radiation equivalent time (BRET) or background equivalent radiation time (BERT) is a unit of measurement of ionizing radiation dosage amounting to one day worth of average human exposure to background radiation.

The collective effective dose, dose quantity S, is calculated as the sum of all individual effective doses over the time period or during the operation being considered due to ionizing radiation. It can be used to estimate the total health effects of a process or accidental release involving ionizing radiation to an exposed population. The total collective dose is the dose to the exposed human population between the time of release until its elimination from the environment, perhaps integrating to time equals infinity. However, doses are generally reported for specific populations and a stated time interval. The International Commission on Radiological Protection (ICRP) states:"To avoid aggregation of low individual doses over extended time periods and wide geographical regions the range in effective dose and the time period should be limited and specified.

<span class="mw-page-title-main">Roentgen (unit)</span> Measurement of radiation exposure

The roentgen or röntgen is a legacy unit of measurement for the exposure of X-rays and gamma rays, and is defined as the electric charge freed by such radiation in a specified volume of air divided by the mass of that air . In 1928, it was adopted as the first international measurement quantity for ionizing radiation to be defined for radiation protection, as it was then the most easily replicated method of measuring air ionization by using ion chambers. It is named after the German physicist Wilhelm Röntgen, who discovered X-rays and was awarded the first Nobel Prize in Physics for the discovery.

<span class="mw-page-title-main">Banana equivalent dose</span> Informal measurement of ionizing radiation exposure; approximately 0.1 microsievert

Banana equivalent dose (BED) is an informal unit of measurement of ionizing radiation exposure, intended as a general educational example to compare a dose of radioactivity to the dose one is exposed to by eating one average-sized banana. Bananas contain naturally occurring radioactive isotopes, particularly potassium-40 (40K), one of several naturally occurring isotopes of potassium. One BED is often correlated to 10−7 sievert ; however, in practice, this dose is not cumulative, as the potassium in foods is excreted in urine to maintain homeostasis. The BED is only meant as an educational exercise and is not a formally adopted dose measurement.

<span class="mw-page-title-main">Orders of magnitude (radiation)</span>

Recognized effects of higher acute radiation doses are described in more detail in the article on radiation poisoning. Although the International System of Units (SI) defines the sievert (Sv) as the unit of radiation dose equivalent, chronic radiation levels and standards are still often given in units of millirems (mrem), where 1 mrem equals 1/1,000 of a rem and 1 rem equals 0.01 Sv. Light radiation sickness begins at about 50–100 rad.

The committed dose in radiological protection is a measure of the stochastic health risk due to an intake of radioactive material into the human body. Stochastic in this context is defined as the probability of cancer induction and genetic damage, due to low levels of radiation. The SI unit of measure is the sievert.

<span class="mw-page-title-main">Radiation exposure</span> Measure of ionization of air by ionizing radiation

Radiation exposure is a measure of the ionization of air due to ionizing radiation from photons. It is defined as the electric charge freed by such radiation in a specified volume of air divided by the mass of that air. As of 2007, "medical radiation exposure" was defined by the International Commission on Radiological Protection as exposure incurred by people as part of their own medical or dental diagnosis or treatment; by persons, other than those occupationally exposed, knowingly, while voluntarily helping in the support and comfort of patients; and by volunteers in a programme of biomedical research involving their exposure. Common medical tests and treatments involving radiation include X-rays, CT scans, mammography, lung ventilation and perfusion scans, bone scans, cardiac perfusion scan, angiography, radiation therapy, and more. Each type of test carries its own amount of radiation exposure. There are two general categories of adverse health effects caused by radiation exposure: deterministic effects and stochastic effects. Deterministic effects are due to the killing/malfunction of cells following high doses; and stochastic effects involve either cancer development in exposed individuals caused by mutation of somatic cells, or heritable disease in their offspring from mutation of reproductive (germ) cells.

References

  1. ↑ Stahmer, U. 11 – 16 September 2016. 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.
  2. ↑ Nuclear Waste Management Organization (2016). Engineer Wins Award for Best Poster. Retrieved 10 December 2021.
  3. ↑ Stahmer, U. (2018-10-24). "Using Flight-Time to Contextualize Radiological Dose". The Physics Teacher. 56 (8): 508–511. doi:10.1119/1.5064556. S2CID   125730267 . Retrieved 2022-04-28.
  4. 1 2 3 Friedberg, W; Copeland K (2011). "Ionizing Radiation in Earth's Atmosphere and in Space Near Earth" Civil Aerospace Medical Institute, Federal Aviation Administration, DOT/FAA/AM- 11/9.
  5. 1 2 3 4 5 Grasty, R.L.; LaMarre, J.R. (2004-02-01). "The annual effective dose from natural sources of ionising radiation in Canada". Radiation Protection Dosimetry. 108 (3): 215–226. doi:10.1093/rpd/nch022. PMID   15031443 . Retrieved 2022-04-28.
  6. ↑ "AAPM Report No. 217 Radiation Dose from Airport Scanners" (PDF). American Association of Physicists in Medicine. June 2013. Retrieved 26 April 2022.
  7. 1 2 3 4 5 "Calculate your radiation dose". United States Environmental Protection Agency. 3 October 2014. Retrieved 2022-04-26.
  8. ↑ Mansfield, G. (1995-03-08). "Banana Equivalent Dose". RadSafe -- The International Radiation Protection (Health Physics) Mailing List. Retrieved 2022-04-28.
  9. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 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:10.1148/radiol.2481071451. PMID   18566177 . Retrieved 2022-04-26.
  10. 1 2 Reitz, G. (1993-05-01). "Radiation Environment in the Stratosphere". Radiation Protection Dosimetry. 48 (1): 5–29. doi:10.1093/oxfordjournals.rpd.a081837 . Retrieved 2022-04-28.
  11. 1 2 Shea, M.A.; Smart, D.F. (August 2001). Comment on Galactic Radiation Dose to Air Crews. 27th International Cosmic Ray Conference. Bibcode:2001ICRC...10.4071S.
  12. 1 2 Bennett, L.G.I.; Lewis, B.J.; Bennett, M.J.; McCall, M.J.; Bean, M (2013). "A Survey of the Cosmic Radiation Exposure of Air Canada Pilots during Maximum Galactic Radiation Conditions in 2009". Radiation Measurements. 49 (1): 103–108. doi:10.1016/j.radmeas.2012.12.004 . Retrieved 2022-04-28.
  13. ↑ Borham, D. (27 October 2010). "Human health and the biological effects of tritium in drinking water". Slide 16. Retrieved 2022-04-26.
  14. ↑ "Report No. 160 – Ionizing Radiation Exposure of the Population of the United States". National Council on Radiation Protection and Measurements. 3 March 2009. Retrieved 26 April 2022.
  15. 1 2 ICRP, International Commission on Radiological Protection. "Dose limits". ICRPedia. ICRP. Retrieved 26 April 2022.
  16. ↑ Bailey, S. (2000). "Air crew radiation exposure – An overview" (PDF). Nuclear News. 43 (1): 32–40. Retrieved 2022-04-26.
  17. ↑ United Nations Environment Programme (2016). Radiation Effects and Sources. United Nations Environment Programme. doi:10.18356/b1749f17-en. ISBN   9789210599597.
  18. ↑ Cucinotta, F.A. (January 1, 2007). "Space Radiation Organ Doses for Astronauts on Past and Future Missions" (PDF). NASA Technical Reports Server. Retrieved 26 April 2022.
  19. ↑ "Radiation Health Effects". 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.
  20. ↑ "Backgrounder on Biological Effects of Radiation". Biological Effects of Radiation. United States Nuclear Regulatory Commission. 2020-07-08. Retrieved 2022-04-28. 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).
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.