Editing X-ray (section)

==Adverse effects==
{{Globalize|section|US|date=September 2024}}
[[File:BabyXray.png|thumb|upright|left|[[Kidneys, ureters, and bladder x-ray|Abdominal radiograph]] of a pregnant woman]]

X-rays are a form of [[ionizing radiation]], and are classified as a [[carcinogen]] by both the World Health Organization's [[International Agency for Research on Cancer]] and the U.S. government.<ref name="Roobottom CA, Mitchell G, Morgan-Hughes G 2010 859–67" /><ref>{{Cite web |url=https://ntp.niehs.nih.gov/go/roc |archive-url=https://web.archive.org/web/20101209082016/https://ntp.niehs.nih.gov/ntp/roc/toc11.html|archive-date=2010-12-09|title=11th Report on Carcinogens |website=Ntp.niehs.nih.gov |access-date=2010-11-08}}</ref>  Diagnostic X-rays (primarily from CT scans due to the large dose used) increase the risk of developmental problems and cancer in those exposed.<ref>{{cite journal | vauthors = Hall EJ, Brenner DJ | title = Cancer risks from diagnostic radiology | journal = The British Journal of Radiology | volume = 81 | issue = 965 | pages = 362–378 | date = May 2008 | pmid = 18440940 | doi = 10.1259/bjr/01948454 }}</ref><ref>{{cite journal | vauthors = Brenner DJ | title = Should we be concerned about the rapid increase in CT usage? | journal = Reviews on Environmental Health | volume = 25 | issue = 1 | pages = 63–68 |date= 2010 | pmid = 20429161 | doi = 10.1515/REVEH.2010.25.1.63 | bibcode = 2010RvEH...25.1.63B }}</ref><ref>{{cite journal | vauthors = De Santis M, Cesari E, Nobili E, Straface G, Cavaliere AF, Caruso A | title = Radiation effects on development | journal = Birth Defects Research. Part C, Embryo Today | volume = 81 | issue = 3 | pages = 177–182 | date = September 2007 | pmid = 17963274 | doi = 10.1002/bdrc.20099 }}</ref>  It is estimated that 0.4% of current cancers in the United States are due to [[computed tomography]] (CT scans) performed in the past and that this may increase to as high as 1.5–2% with 2007 rates of CT usage.<ref name="Brenner 2007" />

Experimental and epidemiological data currently do not support the proposition that there is a [[linear no-threshold model|threshold dose of radiation]] below which there is no increased risk of cancer.<ref>{{cite journal | vauthors = Upton AC | title = The state of the art in the 1990's: NCRP Report No. 136 on the scientific bases for linearity in the dose-response relationship for ionizing radiation | journal = Health Physics | volume = 85 | issue = 1 | pages = 15–22 | date = July 2003 | pmid = 12852466 | doi = 10.1097/00004032-200307000-00005 | bibcode = 2003HeaPh..85...15U }}</ref> However, this is under increasing doubt.<ref>{{cite journal | vauthors = Calabrese EJ, Baldwin LA | title = Toxicology rethinks its central belief | journal = Nature | volume = 421 | issue = 6924 | pages = 691–692 | date = February 2003 | pmid = 12610596 | doi = 10.1038/421691a | bibcode = 2003Natur.421..691C }}</ref> Cancer risk can start at the exposure of 1100 mGy.<ref>{{cite journal | vauthors = Oakley PA, Ehsani NN, Harrison DE | title = The Scoliosis Quandary: Are Radiation Exposures From Repeated X-Rays Harmful? | journal = Dose-Response | volume = 17 | issue = 2 | pages = 1559325819852810 | date = 1 April 2019 | pmid = 31217755 | pmc = 6560808 | doi = 10.1177/1559325819852810 }}</ref> It is estimated that the additional radiation from diagnostic X-rays will increase the average person's cumulative risk of getting cancer by age 75 by 0.6–3.0%.<ref>{{cite journal | vauthors = Berrington de González A, Darby S | title = Risk of cancer from diagnostic X-rays: estimates for the UK and 14 other countries | journal = Lancet | volume = 363 | issue = 9406 | pages = 345–351 | date = January 2004 | pmid = 15070562 | doi = 10.1016/S0140-6736(04)15433-0 }}</ref> The amount of absorbed radiation depends upon the type of X-ray test and the body part involved.<ref name="Brenner 2007">{{cite journal | vauthors = Brenner DJ, Hall EJ | title = Computed tomography—an increasing source of radiation exposure | journal = The New England Journal of Medicine | volume = 357 | issue = 22 | pages = 2277–2284 | date = November 2007 | pmid = 18046031 | doi = 10.1056/NEJMra072149 }}</ref> CT and fluoroscopy entail higher doses of radiation than do plain X-rays.

To place the increased risk in perspective, a plain chest X-ray will expose a person to the same amount from [[background radiation]] that people are exposed to (depending upon location) every day over 10 days, while exposure from a dental X-ray is approximately equivalent to 1 day of environmental background radiation.<ref name="ACR">{{Cite web|publisher=Radiological Society of North America (RSNA) and American College of Radiology (ACR)|title=Radiation Dose in X-Ray and CT Exams|url=https://www.radiologyinfo.org/en/info/safety-xray|access-date=2022-01-24|website=RadiologyInfo.org }}</ref> Each such X-ray would add less than 1 per 1,000,000 to the lifetime cancer risk. An abdominal or chest CT would be the equivalent to 2–3 years of background radiation to the whole body, or 4–5 years to the abdomen or chest, increasing the lifetime cancer risk between 1 per 1,000 to 1 per 10,000.<ref name="ACR" /> This is compared to the roughly 40% chance of a US citizen developing cancer during their lifetime.<ref>{{Cite web |url=http://seer.cancer.gov/csr/1975_2006/browse_csr.php?section=2&page=sect_02_table.11.html#table1 |title=National Cancer Institute: Surveillance Epidemiology and End Results (SEER) data |publisher=Seer.cancer.gov |date=30 June 2010 |access-date=2011-11-08}}</ref> For instance, the effective dose to the torso from a CT scan of the chest is about 5&nbsp;mSv, and the absorbed dose is about 14&nbsp;mGy.<ref>{{Cite journal | vauthors = Caon M, Bibbo G, Pattison J |date=2000 |title= Monte Carlo calculated effective dose to teenage girls from computed tomography examinations |journal=Radiation Protection Dosimetry |volume=90 |issue=4 |pages=445–448 |doi=10.1093/oxfordjournals.rpd.a033172}}</ref> A head CT scan (1.5&nbsp;mSv, 64&nbsp;mGy)<ref name="nrpb2005">Shrimpton, P.C; Miller, H.C; Lewis, M.A; Dunn, M. [http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1194947420292 Doses from Computed Tomography (CT) examinations in the UK – 2003 Review] {{webarchive |url=https://web.archive.org/web/20110922122151/http://www.hpa.org.uk/web/HPAwebFile/HPAweb_C/1194947420292 |date=22 September 2011 }}</ref> that is performed once with and once without contrast agent, would be equivalent to 40 years of background radiation to the head. Accurate estimation of effective doses due to CT is difficult with the estimation uncertainty range of about ±19% to ±32% for adult head scans depending upon the method used.<ref>{{cite journal | vauthors = Gregory KJ, Bibbo G, Pattison JE | title = On the Uncertainties in Effective Dose Estimates of Adult CT Head Scans | journal = Medical Physics | volume = 35 | issue = 8 | pages = 3501–3510 | date = August 2008 | pmid = 18777910 | doi = 10.1118/1.2952359 | bibcode = 2008MedPh..35.3501G }}</ref>

The risk of radiation is greater to a fetus, so in pregnant patients, the benefits of the investigation (X-ray) should be balanced with the potential hazards to the fetus.<ref>{{cite journal | vauthors = Giles D, Hewitt D, Stewart A, Webb J | title = Malignant disease in childhood and diagnostic irradiation in utero | journal = Lancet | volume = 271 | issue = 6940 | pages = 447 | date = September 1956 | pmid = 13358242 | doi = 10.1016/S0140-6736(56)91923-7 }}</ref><ref>{{Cite web |url=http://emedicinelive.com/index.php/Women-s-Health/pregnant-women-and-radiation-exposure.html |title=Pregnant Women and Radiation Exposure |date=28 December 2008 |website=eMedicine Live online medical consultation |publisher=[[Medscape]] |access-date=2009-01-16 |archive-url=https://web.archive.org/web/20090123034228/http://emedicinelive.com/index.php/Women-s-Health/pregnant-women-and-radiation-exposure.html |archive-date=23 January 2009}}{{rs|date=April 2025}}</ref> If there is 1 scan in 9 months, it can be harmful to the fetus.<ref name="Doctor, will that x-ray harm my un">{{cite journal | vauthors = Ratnapalan S, Bentur Y, Koren G | title = "Doctor, will that x-ray harm my unborn child?" | journal = CMAJ | volume = 179 | issue = 12 | pages = 1293–1296 | date = December 2008 | pmid = 19047611 | pmc = 2585137 | doi = 10.1503/cmaj.080247 }}</ref> Therefore, women who are pregnant get ultrasounds as their diagnostic imaging because this does not use radiation.<ref name="Doctor, will that x-ray harm my un" /> If there is too much radiation exposure there could be harmful effects on the fetus or the reproductive organs of the mother.<ref name="Doctor, will that x-ray harm my un" /> In the US, there are an estimated 62&nbsp;million CT scans performed annually, including more than 4&nbsp;million on children.<ref name="Brenner 2007" /> Avoiding unnecessary X-rays (especially CT scans) reduces radiation dose and any associated cancer risk.<ref>{{cite journal | vauthors = Donnelly LF | title = Reducing radiation dose associated with pediatric CT by decreasing unnecessary examinations | journal = AJR. American Journal of Roentgenology | volume = 184 | issue = 2 | pages = 655–657 | date = February 2005 | pmid = 15671393 | doi = 10.2214/ajr.184.2.01840655 }}</ref>

Medical X-rays are a significant source of human-made radiation exposure. In 1987, they accounted for 58% of exposure from human-made sources in the United States. Since human-made sources accounted for only 18% of the total radiation exposure, most of which came from natural sources (82%), medical X-rays only accounted for 10% of ''total'' American radiation exposure; medical procedures as a whole (including [[nuclear medicine]]) accounted for 14% of total radiation exposure. By 2006, however, medical procedures in the United States were contributing much more ionizing radiation than was the case in the early 1980s. In 2006, medical exposure constituted nearly half of the total radiation exposure of the U.S. population from all sources. The increase is traceable to the growth in the use of medical imaging procedures, in particular [[computed tomography]] (CT), and to the growth in the use of nuclear medicine.<ref name=Science09>{{cite press release |title=Medical Radiation Exposure Of The U.S. Population Greatly Increased Since The Early 1980s |url=https://www.sciencedaily.com/releases/2009/03/090303125809.htm |work=ScienceDaily |publisher=National Council on Radiation Protection & Measurements |date=5 March 2009 }}</ref><ref>{{Cite book |last= US National Research Council |title= Health Risks from Low Levels of Ionizing Radiation, BEIR 7 phase 2 |publisher= National Academies Press |date= 2006 |pages= 5, fig.PS–2 |url= https://books.google.com/books?id=Uqj4OzBKlHwC&pg=PA5 |isbn= 978-0-309-09156-5}}, data credited to NCRP (US National Committee on Radiation Protection) 1987</ref>

[[File:Raybloc X-Ray Protective Viewing Window - 2023-10-03 - Andy Mabbett.jpg|thumb|An X-ray protective window at [[Birmingham Dental Hospital]], England. The maker's sticker states that it is equivalent to 2.24mm of lead at 150Kv. ]]

Dosage due to dental X-rays varies significantly depending on the procedure and the technology (film or digital). Depending on the procedure and the technology, a single dental X-ray of a human results in an exposure of 5 to 40&nbsp;μSv. A full mouth series of X-rays may result in an exposure of up to 60 (digital) to 180 (film) μSv, for a yearly average of up to 400&nbsp;μSv.<ref>{{cite web|url=http://www.new.ans.org/pi/resources/dosechart/|title=ANS / Public Information / Resources / Radiation Dose Calculator|access-date=2012-05-16|archive-date=2012-05-16|archive-url=https://web.archive.org/web/20120516085010/http://www.new.ans.org/pi/resources/dosechart/}}</ref><ref>{{Cite web|title=HOW DANGEROUS IS RADIATION?|url=http://www.phyast.pitt.edu/~blc/book/chapter5.html|access-date=2022-01-24|website=PhyAst.Pitt.edu}}</ref><ref>Muller, Richard. '' Physics for Future Presidents'', Princeton University Press, 2010</ref><ref>[http://www.doctorspiller.com/Dental%20_X-Rays.htm X-Rays] {{webarchive|url=https://web.archive.org/web/20070315211141/http://www.doctorspiller.com/Dental%20_X-Rays.htm |date=15 March 2007 }}. Doctorspiller.com (9 May 2007). Retrieved on 2011-05-05.</ref><ref>[http://www.dentalgentlecare.com/x-ray_safety.htm X-Ray Safety] {{webarchive |url=https://web.archive.org/web/20070404222105/http://www.dentalgentlecare.com/x-ray_safety.htm |date=4 April 2007 }}. Dentalgentlecare.com (6 February 2008). Retrieved on 2011-05-05.</ref><ref>{{Cite web |url=http://www.physics.isu.edu/radinf/dental.htm |title=Dental X-Rays |publisher=Idaho State University |access-date=7 November 2012 |archive-date=7 November 2012 |archive-url=https://web.archive.org/web/20121107120350/http://www.physics.isu.edu/radinf/dental.htm |url-status=dead }}</ref><ref>[http://www.oakridge.doe.gov/external/PublicActivities/EmergencyPublicInformation/AboutRadiation/tabid/319/Default.aspx D.O.E. – About Radiation] {{webarchive |url=https://web.archive.org/web/20120427175013/http://www.oakridge.doe.gov/external/PublicActivities/EmergencyPublicInformation/AboutRadiation/tabid/319/Default.aspx |date=27 April 2012 }}</ref>

Financial incentives have been shown to have a significant impact on X-ray use with doctors who are paid a separate fee for each X-ray providing more X-rays.<ref>{{cite journal | vauthors = Chalkley M, Listl S | title = First do no harm – The impact of financial incentives on dental X-rays | journal = Journal of Health Economics | volume = 58 | issue = March 2018 | pages = 1–9 | date = March 2018 | pmid = 29408150 | doi = 10.1016/j.jhealeco.2017.12.005 | doi-access = free | hdl = 2066/190628 | hdl-access = free }}</ref>

Early photon tomography or EPT<ref>{{cite web |url=https://www.open.edu/openlearn/body-mind/using-lasers-instead-x-rays |title=Using lasers instead of x-rays |publisher=Open University |date=24 February 2011 |access-date=28 July 2021}}</ref> (as of 2015) along with other techniques<ref>{{cite web |url=https://www.engadget.com/2015/02/12/visible-light-super-vision/ |title=Scientists achieve X-ray vision with safe, visible light |work=Engadget | vauthors = Dent S |date=12 February 2015 |access-date=28 July 2021}}</ref> are being researched as potential alternatives to X-rays for imaging applications.