Array ( [0] => {{short description|Sound waves with frequencies above the human hearing range}} [1] => {{cs1 config|name-list-style=vanc}} [2] => {{About||the application to medicine|Medical ultrasound|other uses|Ultrasound (disambiguation)|and|Ultrasonic (disambiguation)}} [3] => {{distinguish|Supersonic}} [4] => {{pp-semi-indef}} [5] => {{Use dmy dates|date=July 2022}} [6] => {{EngvarB|date=July 2022}} [7] => [8] => [[File:Aparelhodeultrassom.jpg|thumb|right|An ultrasonic examination]] [9] => [10] => '''Ultrasound''' is [[sound]] with [[frequency|frequencies]] greater than 20 [[Hertz|kilohertz]].{{cite book |editor-last1=Dance |editor-first1=D.R. |editor-last2=Christofides |editor-first2=S. |editor-last3=Maidment |editor-first3=A.D.A. |editor-last4=McLean |editor-first4=I.D. |editor-last5=Ng |editor-first5=K.H. |chapter=12: Physics of Ultrasound |title=Diagnostic Radiology Physics: A Handbook for Teachers and Students |url=https://www.iaea.org/publications/8841/diagnostic-radiology-physics |date=2014 |location=Vienna, Austria |publisher=[[International Atomic Energy Agency]] |page=291 |isbn=978-92-0-131010-1 }} This frequency is the approximate upper audible [[hearing range|limit of human hearing]] in healthy young adults. The physical principles of acoustic waves apply to any frequency range, including ultrasound. Ultrasonic devices operate with frequencies from 20 kHz up to several gigahertz. [11] => [12] => Ultrasound is used in many different fields. Ultrasonic devices are used to detect objects and measure distances. Ultrasound imaging or sonography is often used in medicine. In the [[nondestructive testing]] of products and structures, ultrasound is used to detect invisible flaws. Industrially, ultrasound is used for cleaning, mixing, and accelerating chemical processes. Animals such as [[bat]]s and [[porpoise]]s use ultrasound for locating prey and obstacles.{{cite book |last=Novelline |first=Robert |title=Squire's Fundamentals of Radiology |url=https://archive.org/details/squiresfundament0000nove_f4e9/page/34 |publisher=Harvard University Press |edition=5th |year=1997 |isbn=978-0-674-83339-5 |pages=34–35 }} [13] => [14] => == History == [15] => [[File:Galton whistle.jpg|thumb|Galton whistle, one of the first devices to produce ultrasound]] [16] => [17] => [[Acoustics]], the science of [[sound]], starts as far back as [[Pythagoras]] in the 6th century BC, who wrote on the mathematical properties of [[String instrument|stringed instruments]]. [[Animal echolocation|Echolocation]] in bats was discovered by [[Lazzaro Spallanzani]] in 1794, when he demonstrated that bats hunted and navigated by inaudible sound, not vision. [[Francis Galton]] in 1893 invented the [[Dog whistle|Galton whistle]], an adjustable [[whistle]] that produced ultrasound, which he used to measure the hearing range of humans and other animals, demonstrating that many animals could hear sounds above the hearing range of humans. [18] => [19] => The first article on the history of ultrasound was written in 1948.{{cite journal | vauthors=Klein E | title=Some background history of ultrasonics | journal=Journal of the Acoustical Society of America | year=1948 | volume=20 | issue=5 | pages=601–604 | doi=10.1121/1.1906413| bibcode=1948ASAJ...20..601K }} According to its author, [20] => during the [[First World War]], a Russian engineer named Chilowski submitted an idea for submarine detection to the French Government. The latter invited [[Paul Langevin]], then Director of the School of Physics and Chemistry in Paris, to evaluate it. Chilowski's proposal was to excite a cylindrical, [[mica]] [[capacitor|condenser]] by a high-frequency [[Poulsen arc]] at approximately 100 kHz and thus to generate an ultrasound beam for detecting submerged objects. The idea of locating underwater obstacles had been suggested prior by L. F. Richardson, following the ''[[Titanic]]'' disaster. Richardson had proposed to position a high-frequency [[hydraulic]] [[whistle]] at the focus of a mirror and use the beam for locating submerged navigational hazards. A prototype was built by [[Sir Charles Parsons]], the inventor of the vapour [[turbine]], but the device was found not to be suitable for this purpose. [21] => Langevin's device made use of the [[piezoelectric effect]], which he had been acquainted with whilst a student at the laboratory of [[Jacques Curie|Jacques]] and [[Pierre Curie]].{{cite book | vauthors = Pollet B | title = Power Ultrasound in Electrochemistry: From Versatile Laboratory Tool to Engineering Solution | location=Hoboken | publisher = Wiley | date = 2012 | isbn = 978-1-119-96786-6}} Langevin calculated and built an ultrasound [[transducer]] comprising a thin sheet of [[quartz]] sandwiched between two steel plates. Langevin was the first to report [[cavitation]]-related bioeffects from ultrasound.{{cite thesis | vauthors=Postema M | title=Medical Bubbles | location=Veenendaal | publisher=Universal Press | year=2004 | isbn=90-365-2037-1 | doi=10.5281/zenodo.4771630 | url=https://hal.archives-ouvertes.fr/tel-03195194/document}} [22] => [23] => == Definition == [24] => [[File:Ultrasound range diagram.svg|thumb|425px|right|Approximate frequency ranges corresponding to ultrasound, with rough guide of some applications]] [25] => Ultrasound is defined by the [[ANSI/ASA S1.1-2013|American National Standards Institute]] as "[[sound]] at frequencies greater than 20 kHz". In air at atmospheric pressure, ultrasonic waves have [[wavelength]]s of 1.9 cm or less. [26] => [27] => Ultrasound can be generated at very high frequencies; ultrasound is used for [[sonochemistry]] at frequencies up to multiple hundreds of kilohertz.{{Cite journal|url=https://www.sciencedirect.com/science/article/pii/S1350417796000168|title=The effect of frequency on sonochemical reactions III: dissociation of carbon disulfide|first1=Mohammad H.|last1=Entezari|first2=Peeter|last2=Kruus|first3=Rein|last3=Otson|date=1 January 1997|journal=Ultrasonics Sonochemistry|volume=4|issue=1|pages=49–54|via=ScienceDirect|doi=10.1016/S1350-4177(96)00016-8|pmid=11233925 }}{{Cite journal|title=Effect of frequency on sonochemical reactions. I: Oxidation of iodide|first1=Mohammad H.|last1=Entezari|first2=Peeter|last2=Kruus|date=1 January 1994|journal=Ultrasonics Sonochemistry|volume=1|issue=2|pages=S75–S79|via=ScienceDirect|doi=10.1016/1350-4177(94)90001-9}} Medical imaging equipment uses frequencies in the MHz range.{{Cite journal|url=https://ieeexplore.ieee.org/document/503714|title=A 100-MHz ultrasound imaging system for dermatologic and ophthalmologic diagnostics|journal=IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control|date=1996 |doi=10.1109/58.503714 |s2cid=42359059 |last1=Passmann |first1=C. |last2=Ermert |first2=H. |volume=43 |issue=4 |pages=545–552 }} [[UHF]] ultrasound waves have been generated as high as the gigahertz range.{{Cite journal|title=GHz ultrasound wave packets in water generated by an Er laser|first1=U.|last1=Störkel|first2=K. L.|last2=Vodopyanov|first3=W.|last3=Grill|date=18 September 1998|journal=Journal of Physics D: Applied Physics|volume=31|issue=18|page=2258|via=Institute of Physics|doi=10.1088/0022-3727/31/18/010|bibcode=1998JPhD...31.2258S |s2cid=250886242 }}{{Cite thesis|url=https://www.research-collection.ethz.ch/handle/20.500.11850/22143|title=Applications of GHz Ultrasound: Material Characterization and Wave Propagation in Microstructures|first=Jürg|last=Bryner|date=18 October 2009|publisher=ETH Zurich |doi=10.3929/ethz-a-005902021 |hdl=20.500.11850/22143 |type=Doctoral Thesis |via=www.research-collection.ethz.ch}}{{Cite journal |title=GHz surface-wave ultrasound tomography |journal=Proceedings of a Symposium on Ultrasonic Electronics |author=Hayato Takeda |author2=Paul Otsuka |author3=Motonobu Tomoda |author4=Osamu Matsuda |author5=Oliver B. Wright |date=2019 |volume=40|article-number=3J2–2 |doi=10.24492/use.40.0_3J2-2 |doi-access=free}} [28] => [29] => Characterizing extremely high-frequency ultrasound poses challenges, as such rapid movement causes waveforms to steepen and form [[shock waves]].{{cite journal|url=https://pubs.aip.org/asa/jasa/article/153/5/2878/2890440|first1=Ehsan|last1=Vatankhah|first2=Yuqi|last2=Meng|first3=Zihuan|last3=Liu|first4=Xiaoyu|last4=Niu|first5=Neal A.|last5=Hall|title=Characterization of high intensity progressive ultrasound beams in air at 300 kHz|doi=10.1121/10.0019376 [30] => |journal=The Journal of the Acoustical Society of America|date=2023 |volume=153 |issue=5 |page=2878 |pmid=37171898 |bibcode=2023ASAJ..153.2878V |s2cid=258659463 }} [31] => [32] => == Perception == [33] => === Humans === [34] => The upper frequency limit in humans (approximately 20 kHz) is due to limitations of the [[middle ear]]. [[Ultrasonic hearing|Auditory sensation]] can occur if high‐intensity ultrasound is fed directly into the [[human skull]] and reaches the [[cochlea]] through [[bone conduction]], without passing through the middle ear.{{cite journal | vauthors = Corso JF |year=1963 |title=Bone-conduction thresholds for sonic and ultrasonic frequencies |journal=Journal of the Acoustical Society of America |volume=35 |issue=11 |pages=1738–1743 |doi=10.1121/1.1918804 |bibcode = 1963ASAJ...35.1738C }} [35] => [36] => Children can hear some high-pitched sounds that older adults cannot hear, because in humans the upper limit pitch of hearing tends to decrease with age.{{cite journal | vauthors = Takeda S, Morioka I, Miyashita K, Okumura A, Yoshida Y, Matsumoto K | title = Age variation in the upper limit of hearing | journal = European Journal of Applied Physiology and Occupational Physiology | volume = 65 | issue = 5 | pages = 403–8 | year = 1992 | pmid = 1425644 | doi = 10.1007/BF00243505 | s2cid = 33698151 }} An American [[cell phone]] company has used this to create ring signals that supposedly are only audible to younger humans,{{cite news | first = Paul | last = Vitello | date = 12 June 2006 | newspaper = The New York Times | url = https://www.nytimes.com/2006/06/12/technology/12ring.html | title = A Ring Tone Meant to Fall on Deaf Ears }} but many older people can hear the signals, which may be because of the considerable variation of age-related deterioration in the upper hearing threshold. [37] => [38] => === Animals === [39] => [[File:Big-eared-townsend-fledermaus.jpg|thumb|Bats use ultrasounds to navigate in the darkness.]] [40] => [[File:Hundepfeife01.JPG|thumb|A [[dog whistle]], which emits sound in the ultrasonic range, used to train dogs and other animals]] [41] => [42] => [[Bat]]s use a variety of ultrasonic ranging ([[Animal echolocation|echolocation]]) techniques to detect their prey. They can detect frequencies beyond 100 kHz, possibly up to 200 kHz.{{cite book | title = Hearing by Bats | series = Springer Handbook of Auditory Research | volume = 5 | veditors = Popper A, Fay RR | publisher = Springer | date = 1995 | isbn = 978-1-4612-2556-0 }} [43] => [44] => Many [[insect]]s have good ultrasonic hearing, and most of these are [[nocturnal]] insects listening for echolocating bats. These include many groups of [[moth]]s, [[beetles]], [[praying mantis]]es and [[lacewings]]. Upon hearing a bat, some insects will make [[Ultrasound avoidance|evasive manoeuvres]] to escape being caught.{{cite journal |vauthors=Surlykke A, Miller LA |title=How some insects detect and avoid being eaten by bats: Tactics and counter tactics of prey and predator. |journal=BioScience |volume=51 |issue=7 |page=570 |year=2001 |doi=10.1641/0006-3568(2001)051[0570:HSIDAA]2.0.CO;2 |doi-access=free }} Ultrasonic frequencies trigger a [[reflex action]] in the [[noctuid]] moth that causes it to drop slightly in its flight to evade attack.{{cite journal | vauthors = Jones G, Waters DA | title = Moth hearing in response to bat echolocation calls manipulated independently in time and frequency | journal = Proceedings. Biological Sciences | volume = 267 | issue = 1453 | pages = 1627–32 | date = August 2000 | pmid = 11467425 | pmc = 1690724 | doi = 10.1098/rspb.2000.1188 }} [[Arctiidae|Tiger moth]]s also emit clicks which may disturb bats' echolocation,{{cite web|url=http://news.nationalgeographic.com/news/2009/07/090717-moths-jam-bat-sonar.html|title=Moths Jam Bat Sonar, Throw the Predators Off Course|date=July 17, 2009| first = Matt | last = Kaplan |publisher=National Geographic News|access-date=2009-08-26|archive-url=https://web.archive.org/web/20090822014813/http://news.nationalgeographic.com/news/2009/07/090717-moths-jam-bat-sonar.html|archive-date=2009-08-22}}{{cite news | url = https://www.npr.org/templates/story/story.php?storyId=106733884 | title = Some Moths Escape Bats By Jamming Sonar | work = Talk of the Nation | publisher = National Public Radio | archive-url = https://web.archive.org/web/20170810131957/http://www.npr.org/templates/story/story.php?storyId=106733884 | archive-date=2017-08-10 }} and in other cases may advertise the fact that they are poisonous by emitting sound.{{cite journal|vauthors=Surlykke A, Miller LA|url=http://batlab.dk/pubs/85clicks.pdf|year=1985|title=The influence of arctiid moth clicks on bat echolocation; jamming or warning?|journal=Journal of Comparative Physiology A |volume=156 |pages=831–843 |doi=10.1007/BF00610835 |issue=6 |s2cid=25308785|archive-url= https://web.archive.org/web/20120425161548/http://batlab.dk/pubs/85clicks.pdf |archive-date=2012-04-25 }}{{cite book | vauthors = Tougaard J, Miller LA, Simmons JA | chapter = The role of arctiid moth clicks in defense against echolocating bats: interference with temporal processing | date = 2003 | title = Advances in the study of echolocation in bats and dolphins | veditors = Thomas J, Moss CF, Vater M | pages = 365–372 | publisher = Chicago University Press | location = Chicago }} [45] => [46] => Dogs and cats' hearing range extends into the ultrasound; the top end of a dog's hearing range is about 45 kHz, while a cat's is 64 kHz.{{cite book| last=Krantz| first=Les | title=Power of the Dog: Things Your Dog Can Do That You Can't| publisher=MacMillan| date=2009| pages=35–37| url=https://books.google.com/books?id=0l6jeMrA184C&q=%22dog+whistle%22+frequency&pg=PA36| isbn=978-0-312-56722-4}}{{cite web| last=Strain| first=George M.| title=How Well Do Dogs and Other Animals Hear?| work=Prof. Strain's website| publisher=School of Veterinary Medicine, Louisiana State University| date=2010| url=http://www.lsu.edu/deafness/HearingRange.html| access-date=July 21, 2012| archive-url=https://web.archive.org/web/20110808044148/http://www.lsu.edu/deafness/HearingRange.html| archive-date=August 8, 2011}} The wild ancestors of cats and dogs evolved this higher hearing range to hear high-frequency sounds made by their preferred prey, small rodents. A [[dog whistle]] is a whistle that emits ultrasound, used for training and calling dogs. The frequency of most dog whistles is within the range of 23 to 54 kHz.{{cite journal | first1 = D Caroline | last1 = Coile | first2 = Margaret H | last2 = Bonham | title=Why Do Dogs Like Balls?: More Than 200 Canine Quirks, Curiosities, and Conundrums Revealed| url=https://books.google.com/books?id=uqe_I8Q83yAC&q=dog%20whistle%20frequency&pg=PA116 | year=2008| journal=Sterling Publishing Company, Inc| page=116 | isbn=978-1-4027-5039-7 }} [47] => [48] => [[Toothed whales]], including [[dolphins]], can hear ultrasound and use such sounds in their navigational system ([[biosonar]]) to orient and to capture prey.{{cite book| vauthors = Whitlow WL |title=The sonar of dolphins|url=https://books.google.com/books?id=Q3MIsrPDA5EC|access-date=13 November 2011|year=1993|publisher=Springer|isbn=978-0-387-97835-2}} [[Porpoises]] have the highest known upper hearing limit at around 160 kHz.{{cite journal | vauthors = Kastelein RA, Bunskoek P, Hagedoorn M, Au WW, de Haan D | title = Audiogram of a harbor porpoise (Phocoena phocoena) measured with narrow-band frequency-modulated signals | journal = The Journal of the Acoustical Society of America | volume = 112 | issue = 1 | pages = 334–44 | date = July 2002 | pmid = 12141360 | doi = 10.1121/1.1480835 | bibcode = 2002ASAJ..112..334K }} Several types of fish can detect ultrasound. In the order [[Clupeiformes]], members of the subfamily [[Alosinae]] ([[shad]]) have been shown to be able to detect sounds up to 180 kHz, while the other subfamilies (e.g. [[herring]]s) can hear only up to 4 kHz.{{cite journal | vauthors = Mann DA, Higgs DM, Tavolga WN, Souza MJ, Popper AN | title = Ultrasound detection by clupeiform fishes | journal = The Journal of the Acoustical Society of America | volume = 109 | issue = 6 | pages = 3048–54 | date = June 2001 | pmid = 11425147 | doi = 10.1121/1.1368406 | bibcode = 2001ASAJ..109.3048M | url = https://scholar.uwindsor.ca/cgi/viewcontent.cgi?article=1050&context=biologypub }} [49] => [50] => No bird species have been reported to be sensitive to ultrasound.{{Cite web|url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1076&context=icwdm_usdanwrc|title=What Can Birds Hear|last=|first=|date=|website=University Of Nebraska|access-date=31 August 2016}} [51] => [52] => Commercial ultrasonic systems have been sold for supposed indoors [[electronic pest control]] and outdoors [[ultrasonic algae control]]. However, no scientific evidence exists on the success of such devices for these purposes.{{cite book | title = Food plant sanitation | last = Hui | first = Yiu H. | year = 2003 | publisher = CRC Press | isbn = 978-0-8247-0793-4 | page = 289 | url = https://books.google.com/books?id=5oIO2hzQD6wC&pg=PA289 }}{{cite book | title = Vertebrate pests: problems and control; Volume 5 of Principles of plant and animal pest control, National Research Council (U.S.). Committee on Plant and Animal Pests; Issue 1697 of Publication (National Research Council (U.S.))) | year = 1970 | publisher = National Academies | page = 92 | url = https://books.google.com/books?id=uDorAAAAYAAJ&pg=PA92 }}{{cite book |vauthors=Jackson WB, McCartney WC, Ashton AD |chapter=Protocol for Field Tests of Ultrasonic Devices for Rodent Management |title=Vertebrate pest control and management materials |volume=6 |veditors=Fagerstone KA, Curnow RD |year=1989 |publisher=ASTM International |isbn=978-0-8031-1281-0 |page=8 |url=https://books.google.com/books?id=vYGZs2A7S_IC}} [53] => [54] => ==Detection and ranging== [55] => [56] => ===Non-contact sensor=== [57] => An ultrasonic level or sensing system requires no contact with the target. For many processes in the medical, pharmaceutical, military and general industries this is an advantage over inline sensors that may contaminate the liquids inside a vessel or tube or that may be clogged by the product. [58] => [59] => Both continuous wave and pulsed systems are used. The principle behind a pulsed-ultrasonic technology is that the transmit signal consists of short bursts of ultrasonic energy. After each burst, the electronics looks for a return signal within a small window of time corresponding to the time it takes for the energy to pass through the vessel. Only a signal received during this window will qualify for additional signal processing. [60] => [61] => A popular consumer application of ultrasonic ranging was the [[Polaroid SX-70]] camera, which included a lightweight transducer system to focus the camera automatically. Polaroid later licensed this ultrasound technology and it became the basis of a variety of ultrasonic products. [62] => [63] => ===Motion sensors and flow measurement=== [64] => A common ultrasound application is an automatic door opener, where an ultrasonic sensor detects a person's approach and opens the door. Ultrasonic sensors are also used to detect intruders; the ultrasound can cover a wide area from a single point. The flow in pipes or open channels can be measured by ultrasonic flowmeters, which measure the average velocity of flowing liquid. In [[rheology]], an [[acoustic rheometer]] relies on the principle of ultrasound. In [[fluid mechanics]], fluid flow can be measured using an [[ultrasonic flow meter]]. [65] => [66] => ===Nondestructive testing=== [67] => {{See also|Macrosonics|Ultrasonic testing}} [68] => [[File:UT principe.svg|thumb|right| Principle of flaw detection with ultrasound. A void in the solid material reflects some energy back to the transducer, which is detected and displayed.]] [69] => [70] => [[Ultrasonic testing]] is a type of [[nondestructive testing]] commonly used to find flaws in materials and to measure the thickness of objects. Frequencies of 2 to 10 MHz are common, but for special purposes other frequencies are used. Inspection may be manual or automated and is an essential part of modern manufacturing processes. Most metals can be inspected as well as plastics and [[aerospace]] [[Composite material|composites]]. Lower frequency ultrasound (50–500 kHz) can also be used to inspect less dense materials such as wood, [[concrete]] and [[cement]]. [71] => [72] => Ultrasound inspection of welded joints has been an alternative to [[radiography]] for nondestructive testing since the 1960s. Ultrasonic inspection eliminates the use of ionizing radiation, with safety and cost benefits. Ultrasound can also provide additional information such as the depth of flaws in a welded joint. Ultrasonic inspection has progressed from manual methods to computerized systems that automate much of the process. An ultrasonic test of a joint can identify the existence of flaws, measure their size, and identify their location. Not all welded materials are equally amenable to ultrasonic inspection; some materials have a large grain size that produces a high level of background noise in measurements.{{cite book | veditors = Buschow KH, etal | title = Encyclopedia of Materials | publisher = Elsevier | date = 2001 | isbn = 978-0-08-043152-9 | page = 5990 }} [73] => [[File:Swing shaft spline cracking.png|thumb|right|Non-destructive testing of a swing shaft showing [[Spline (mechanical)|spline]] cracking]] [74] => [75] => [[Ultrasonic thickness measurement]] is one technique used to monitor quality of welds. [76] => [77] => ===Ultrasonic range finding=== [78] => [[File:Sonar Principle EN.svg|thumb|400px|Principle of an active sonar]] [79] => {{Main|Sonar}} [80] => A common use of ultrasound is in underwater [[range finding]]; this use is also called [[sonar]]. An ultrasonic pulse is generated in a particular direction. If there is an object in the path of this pulse, part or all of the pulse will be reflected back to the transmitter as an [[Echo (phenomenon)|echo]] and can be detected through the receiver path. By measuring the difference in time between the pulse being transmitted and the echo being received, it is possible to determine the distance. [81] => [82] => The measured travel time of Sonar pulses in water is strongly dependent on the temperature and the salinity of the water. Ultrasonic ranging is also applied for measurement in air and for short distances. For example, hand-held ultrasonic measuring tools can rapidly measure the layout of rooms. [83] => [84] => Although range finding underwater is performed at both sub-audible and audible frequencies for great distances (1 to several kilometers), ultrasonic range finding is used when distances are shorter and the accuracy of the distance measurement is desired to be finer. Ultrasonic measurements may be limited through barrier layers with large salinity, temperature or vortex differentials. Ranging in water varies from about hundreds to thousands of meters, but can be performed with centimeters to meters accuracy [85] => [86] => ===Ultrasound Identification (USID)=== [87] => [[Ultrasound Identification]] (USID) is a [[Real-time locating system|Real-Time Locating System]] (RTLS) or [[Indoor Positioning System]] (IPS) technology used to automatically track and identify the location of objects in real time using simple, inexpensive nodes (badges/tags) attached to or embedded in objects and devices, which then transmit an ultrasound signal to communicate their location to microphone sensors. [88] => [89] => ==Imaging== [90] => [[File:Embryo at 14 weeks profile.JPG|thumb|right|[[Obstetric ultrasonography|Sonogram]] of a fetus at 14 weeks (profile)]] [91] => [[File:3dultrasound.png|thumb|right|Head of a fetus, aged 29 weeks, in a "[[3D ultrasound]]"]] [92] => The potential for ultrasonic imaging of objects, in which a 3 GHz sound wave could produce resolution comparable to an optical image, was recognized by Sergei Sokolov in 1939. Such frequencies were not possible at the time, and what technology did exist produced relatively low-contrast images with poor sensitivity. [93] => Ultrasonic imaging uses frequencies of 2 megahertz and higher; the shorter wavelength allows resolution of small internal details in structures and tissues. The power density is generally less than 1 watt per square centimetre to avoid heating and cavitation effects in the object under examination. Ultrasonic imaging applications include industrial nondestructive testing, quality control and medical uses.{{cite book | veditors = Papadakis EP | title = Ultrasonic Instruments & Devices | publisher = Academic Press | date = 1999 | isbn = 978-0-12-531951-5 | page = 752 }} [94] => [95] => ===Acoustic microscopy=== [96] => [[Acoustic microscopy]] is the technique of using sound waves to visualize structures too small to be resolved by the human eye. High and ultra high frequencies up to several gigahertz are used in acoustic microscopes. The reflection and diffraction of sound waves from microscopic structures can yield information not available with light. [97] => [98] => ===Human medicine=== [99] => [[Medical ultrasound]] is an ultrasound-based diagnostic [[medical imaging]] technique used to visualize muscles, tendons, and many internal organs to capture their size, structure and any pathological [[lesion]]s with real time tomographic images. Ultrasound has been used by [[radiologist]]s and [[sonographer]]s to image the human body for at least 50 years and has become a widely used diagnostic tool. The technology is relatively inexpensive and portable, especially when compared with other techniques, such as [[magnetic resonance imaging]] (MRI) and [[computed tomography]] (CT). Ultrasound is also used to visualize fetuses during routine and emergency [[prenatal care]]. Such diagnostic applications used during [[pregnancy]] are referred to as [[Obstetric ultrasonography|obstetric sonography]]. As currently applied in the medical field, properly performed ultrasound poses no known risks to the patient.{{cite journal | vauthors = Hangiandreou NJ | title = AAPM/RSNA physics tutorial for residents. Topics in US: B-mode US: basic concepts and new technology | journal = Radiographics | volume = 23 | issue = 4 | pages = 1019–33 | year = 2003 | pmid = 12853678 | doi = 10.1148/rg.234035034 }} Sonography does not use [[ionizing radiation]], and the power levels used for imaging are too low to cause adverse heating or pressure effects in tissue.{{Cite web|url=https://www.fda.gov/radiation-emittingproducts/radiationemittingproductsandprocedures/medicalimaging/ucm115357.htm|title=Medical Imaging{{Snd}} Ultrasound Imaging| author = Center for Devices and Radiological Health |website=www.fda.gov|language=en|access-date=2019-04-18}}{{cite journal | vauthors = Ter Haar G | title = Ultrasonic imaging: safety considerations | journal = Interface Focus | volume = 1 | issue = 4 | pages = 686–97 | date = August 2011 | pmid = 22866238 | pmc = 3262273 | doi = 10.1098/rsfs.2011.0029 }} Although the long-term effects due to ultrasound exposure at diagnostic intensity are still unknown,{{cite web | url = https://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/ucm115357.htm | title = FDA Radiological Health{{Snd}} Ultrasound Imaging | archive-url = https://web.archive.org/web/20150703170404/https://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/ucm115357.htm |archive-date = 2015-07-03 | publisher = United States Food and Drug Administration | date = 2011-09-06 | access-date = 2011-11-13 }} currently most doctors feel that the benefits to patients outweigh the risks.{{cite web | url = http://www.aium.org/patient/aboutexam/safety.asp | archive-url = https://web.archive.org/web/20070221101616/http://www.aium.org/patient/aboutexam/safety.asp | archive-date = 2007-02-21 | title = Patient Information{{Snd}} Ultrasound Safety | publisher = American Institute of Ultrasound in Medicine }} The ALARA (As Low As Reasonably Achievable) principle has been advocated for an ultrasound examination{{Snd}} that is, keeping the scanning time and power settings as low as possible but consistent with diagnostic imaging{{Snd}} and that by that principle nonmedical uses, which by definition are not necessary, are actively discouraged.{{cite web | url = http://www.aium.org/resources/guidelines.aspx | title = American Institute for Ultrasound in Medicine practice guidelines | archive-url = https://web.archive.org/web/20150701090209/http://www.aium.org/resources/guidelines.aspx | archive-date = 2015-07-01 | publisher = American Institute for Ultrasound in Medicine | access-date = 2015-07-01 }} [100] => [101] => Ultrasound is also increasingly being used in trauma and first aid cases, with [[emergency ultrasound]] becoming a staple of most EMT response teams. Furthermore, ultrasound is used in remote diagnosis cases where [[teleconsultation]] is required, such as scientific experiments in space or mobile sports team diagnosis.{{cite web | url = http://www.epiphan.com/solutions_new/?arid=1082 | title = DistanceDoc and MedRecorder: New Approach to Remote Ultrasound Imaging Solutions | publisher = Epiphan Systems | archive-url = https://web.archive.org/web/20110214122805/http://www.epiphan.com/solutions_new/?arid=1082 | archive-date = 2011-02-14 }} [102] => [103] => According to RadiologyInfo,{{cite web|url=http://www.radiologyinfo.org/en/info.cfm?pg=pelvus&bhcp=1|title=Ultrasound Imaging of the Pelvis|work=radiologyinfo.org|access-date=2008-06-21|archive-url=https://web.archive.org/web/20080625070931/http://www.radiologyinfo.org/en/info.cfm?pg=pelvus&bhcp=1|archive-date=2008-06-25|url-status=live}} ultrasounds are useful in the detection of [[human pelvis|pelvic]] abnormalities and can involve techniques known as [[Abdomen|abdominal]] (transabdominal) ultrasound, [[vagina]]l (transvaginal or endovaginal) ultrasound in women, and also [[Rectum|rectal]] (transrectal) ultrasound in men. [104] => [105] => === Veterinary medicine === [106] => {{See also|Preclinical imaging}} [107] => Diagnostic ultrasound is used externally in horses for evaluation of soft tissue and tendon injuries, and internally in particular for reproductive work{{Snd}}evaluation of the reproductive tract of the mare and pregnancy detection.{{cite web | vauthors = Pycock JF | title = Ultrasound characteristics of the uterus in the cycling mare and their correlation with steroid hormones and timing of ovulation | url = http://www.equine-reproduction.com/articles/ultrasound-steroids.shtml | archive-url = https://web.archive.org/web/20090131144526/http://equine-reproduction.com/articles/ultrasound-steroids.shtml | archive-date = 31 January 2009 }} It may also be used in an external manner in stallions for evaluation of testicular condition and diameter as well as internally for reproductive evaluation (deferent duct etc.).{{cite book | vauthors = McKinnon AO, Voss JL | title = Equine Reproduction | publisher = Lea & Febiger | date = 1993 | isbn = 978-0-8121-1427-0 }} [108] => [109] => By 2005, ultrasound technology began to be used by the beef [[cattle]] industry to improve animal health and the yield of cattle operations.{{cite web [110] => |url=http://deltafarmpress.com/news/050520-subiaco-angus/ [111] => |title=Subiaco Abbey's Angus herd [112] => |vauthors = Bennett D [113] => |date=May 19, 2005 [114] => |work=Delta Farm Press [115] => |archive-url=https://web.archive.org/web/20070404221048/http://deltafarmpress.com/news/050520-subiaco-angus/ [116] => |archive-date=April 4, 2007 [117] => |access-date=February 27, 2010 }} Ultrasound is used to evaluate fat thickness, rib eye area, and intramuscular fat in living animals.{{cite web [118] => |url = http://www.caf.wvu.edu/~forage/breeding/cattlebr.htm [119] => |title = Extension Effort in Beef Cattle Breeding & Selection [120] => |vauthors = Wagner W [121] => |work = [[West Virginia University]] Extension Service [122] => |archive-url = https://web.archive.org/web/20081214174609/http://www.caf.wvu.edu/~forage/breeding/cattlebr.htm [123] => |archive-date = December 14, 2008 [124] => |access-date = February 27, 2010 [125] => }} It is also used to evaluate the health and characteristics of unborn calves. [126] => [127] => Ultrasound technology provides a means for cattle producers to obtain information that can be used to improve the breeding and husbandry of cattle. The technology can be expensive, and it requires a substantial time commitment for continuous data collection and operator training. Nevertheless, this technology has proven useful in managing and running a cattle breeding operation. [128] => [129] => ==Processing and power== [130] => High-power applications of ultrasound often use frequencies between 20 kHz and a few hundred kHz. Intensities can be very high; above 10 watts per square centimeter, cavitation can be inducted in liquid media, and some applications use up to 1000 watts per square centimeter. Such high intensities can induce chemical changes or produce significant effects by direct mechanical action, and can inactivate harmful microorganisms.{{cite book | vauthors = Betts GD, Williams A, Oakley RM | chapter = Inactivation of Food-borne Microorganisms using Power Ultrasound | veditors = Robinson RK, Batt CA, Patel PD | title = Encyclopedia of Food Microbiology | publisher = Academic Press | date = 2000 | isbn = 978-0-12-227070-3 | page = 2202 }} [131] => [132] => ===Physical therapy=== [133] => {{main|Therapeutic ultrasound}} [134] => Ultrasound has been used since the 1940s by physical and occupational therapists for treating [[connective tissue]]: [[ligament]]s, [[tendon]]s, and [[fascia]] (and also [[Granulation tissue|scar tissue]]).{{cite web | url = http://www.electrotherapy.org/electro/downloads/Therapeutic%20Ultrasound.pdf | vauthors = Watson T | date = 2006 | title = Therapeutic Ultrasound | archive-url = https://web.archive.org/web/20070412093629/http://www.electrotherapy.org/electro/downloads/Therapeutic%20Ultrasound.pdf | archive-date = 2007-04-12 }} for a pdf version with the author and date information) Conditions for which ultrasound may be used for treatment include the follow examples: ligament [[sprain]]s, muscle [[strain (injury)|strains]], [[tendonitis]], joint inflammation, [[plantar fasciitis]], [[metatarsalgia]], facet irritation, [[impingement syndrome]], [[bursitis]], [[rheumatoid arthritis]], [[osteoarthritis]], and scar tissue adhesion. [135] => [136] => Relatively high power ultrasound can break up stony deposits or tissue, increase [[skin permeability]], accelerate the effect of drugs in a targeted area, assist in the measurement of the elastic properties of tissue, and can be used to sort cells or small particles for research.{{cite book | title = Essentials of Medical Ultrasound: A Practical Introduction to the Principles, Techniques and Biomedical Applications | veditors = Rapacholi MH | publisher = Humana Press | date = 1982 }} [137] => [138] => ===Ultrasonic impact treatment=== [139] => [[Ultrasonic impact treatment]] (UIT) uses ultrasound to enhance the mechanical and physical properties of metals.{{Cite web| first = Efim | last = Statnikov |url=https://www.researchgate.net/publication/240819725|title=Physics and mechanism of ultrasonic impact treatment | publisher = International Institute of Welding }} It is a metallurgical processing technique in which ultrasonic energy is applied to a metal object. Ultrasonic treatment can result in controlled residual compressive stress, grain refinement and grain size reduction. Low and high cycle fatigue are enhanced and have been documented to provide increases up to ten times greater than non-UIT specimens. Additionally, UIT has proven effective in addressing [[stress corrosion cracking]], [[corrosion fatigue]] and related issues. [140] => [141] => When the UIT tool, made up of the ultrasonic transducer, pins and other components, comes into contact with the work piece it acoustically couples with the work piece, creating harmonic resonance.{{cite web|title=UIT Solutions Video|url=http://www.appliedultrasonics.com/solutions_video.html|work=appliedultrasonics.com|access-date=28 September 2012|archive-url=https://web.archive.org/web/20120510085911/http://www.appliedultrasonics.com/solutions_video.html|archive-date=2012-05-10|url-status=live}} This harmonic resonance is performed at a carefully calibrated frequency, to which metals respond very favorably. [142] => [143] => Depending on the desired effects of treatment a combination of different frequencies and displacement amplitude is applied. These frequencies range between 25 and 55 kHz,{{cite web |title=Tools of the Trade |url=http://appliedultrasonics.com/solutions.html|work=appliedultrasonics.com|access-date=28 September 2012|archive-url=https://web.archive.org/web/20080531004615/http://www.appliedultrasonics.com/solutions.html|archive-date=2008-05-31|url-status=live}} with the displacement amplitude of the resonant body of between 22 and 50 µm (0.00087 and 0.0020 in). [144] => [145] => UIT devices rely on [[magnetostrictive]] transducers. [146] => [147] => ===Processing=== [148] => {{main|Sonication}} [149] => Ultrasonication offers great potential in the processing of liquids and slurries, by improving the mixing and chemical reactions in various applications and industries. Ultrasonication generates alternating low-pressure and high-pressure waves in liquids, leading to the formation and violent collapse of small [[vacuum]] bubbles. This phenomenon is termed [[cavitation]] and causes high speed impinging liquid jets and strong hydrodynamic shear-forces. These effects are used for the deagglomeration and milling of micrometre and nanometre-size materials as well as for the disintegration of cells or the mixing of reactants. In this aspect, ultrasonication is an alternative to high-speed mixers and agitator bead mills. Ultrasonic foils under the moving wire in a paper machine will use the shock waves from the imploding bubbles to distribute the cellulose fibres more uniformly in the produced paper web, which will make a stronger paper with more even surfaces. Furthermore, chemical reactions benefit from the free radicals created by the cavitation as well as from the energy input and the material transfer through boundary layers. For many processes, this sonochemical (see [[sonochemistry]]) effect leads to a substantial reduction in the reaction time, like in the [[transesterification]] of oil into [[biodiesel]].{{Citation needed|date=July 2020}} [150] => [[File:Schematic of bench and industrial-scale ultrasonic liquid processors produced by Industrial Sonomechanics, LLC.jpg|thumbnail|Schematic of bench and industrial-scale ultrasonic liquid processors]] [151] => [152] => Substantial ultrasonic intensity and high ultrasonic vibration amplitudes are required for many processing applications, such as nano-crystallization, nano-emulsification,{{cite journal | vauthors = Peshkovsky AS, Peshkovsky SL, Bystryak S | title = Scalable high-power ultrasonic technology for the production of translucent nanoemulsions. | journal = Chemical Engineering and Processing: Process Intensification | date = July 2013 | volume = 69 | pages = 77–82 | doi = 10.1016/j.cep.2013.02.010 | bibcode = 2013CEPPI..69...77P }} deagglomeration, extraction, cell disruption, as well as many others. Commonly, a process is first tested on a laboratory scale to prove feasibility and establish some of the required ultrasonic exposure parameters. After this phase is complete, the process is transferred to a pilot (bench) scale for flow-through pre-production optimization and then to an industrial scale for continuous production. During these scale-up steps, it is essential to make sure that all local exposure conditions (ultrasonic amplitude, [[cavitation]] intensity, time spent in the active cavitation zone, etc.) stay the same. If this condition is met, the quality of the final product remains at the optimized level, while the productivity is increased by a predictable "scale-up factor". The productivity increase results from the fact that laboratory, bench and industrial-scale ultrasonic processor systems incorporate progressively larger [[ultrasonic horn]]s, able to generate progressively larger high-intensity cavitation zones and, therefore, to process more material per unit of time. This is called "direct scalability". It is important to point out that increasing the power of the ultrasonic processor alone does ''not'' result in direct scalability, since it may be (and frequently is) accompanied by a reduction in the ultrasonic amplitude and cavitation intensity. During direct scale-up, all processing conditions must be maintained, while the power rating of the equipment is increased in order to enable the operation of a larger ultrasonic horn.{{cite journal | vauthors = Peshkovsky SL, Peshkovsky AS | title = Matching a transducer to water at cavitation: acoustic horn design principles | journal = Ultrasonics Sonochemistry | volume = 14 | issue = 3 | pages = 314–22 | date = March 2007 | pmid = 16905351 | doi = 10.1016/j.ultsonch.2006.07.003 | doi-access = free }}{{cite book | vauthors = Peshkovsky AS, Peshkovsky SL | chapter = Industrial-scale processing of liquids by high-intensity acoustic cavitation-the underlying theory and ultrasonic equipment design principles | veditors = Nowak FM | title = Sonochemistry: Theory, Reactions and Syntheses, and Applications | location = Hauppauge, NY | publisher = Nova Science Publishers | date = 2010 }}{{cite book | vauthors = Peshkovsky AS, Peshkovsky SL | title = Acoustic cavitation theory and equipment design principles for industrial applications of high-intensity ultrasound | location = Hauppauge, NY | publisher = Nova Science Publishers | date = 2010 | series = Physics Research and Technology }} [153] => [154] => ===Ultrasonic manipulation and characterization of particles=== [155] => A researcher at the Industrial Materials Research Institute, Alessandro Malutta, devised an experiment that demonstrated the trapping action of ultrasonic standing waves on wood pulp fibers diluted in water and their parallel orienting into the equidistant pressure planes.{{cite journal | vauthors = Dion JL, Malutta A, Cielo P |title=Ultrasonic inspection of fiber suspensions |journal=Journal of the Acoustical Society of America |volume=72 |issue=5 |date = November 1982 |pages=1524–1526 |doi=10.1121/1.388688 |bibcode = 1982ASAJ...72.1524D }} The time to orient the fibers in equidistant planes is measured with a laser and an electro-optical sensor. This could provide the paper industry a quick on-line fiber size measurement system. A somewhat different implementation was demonstrated at Pennsylvania State University using a microchip which generated a pair of perpendicular standing surface acoustic waves allowing to position particles equidistant to each other on a grid. This experiment, called [[acoustic tweezers]], can be used for applications in material sciences, biology, physics, chemistry and nanotechnology. [156] => [157] => ===Ultrasonic cleaning=== [158] => {{Main|Ultrasonic cleaning}} [159] => [160] => [[Ultrasonic cleaner]]s, sometimes mistakenly called ''[[supersonic]] cleaners'', are used at frequencies from 20 to 40 [[Hertz|kHz]] for jewellery, lenses and other optical parts, watches, [[dentistry|dental instrument]]s, [[surgical instrument]]s, [[diving regulator]]s and industrial parts. An ultrasonic cleaner works mostly by energy released from the collapse of millions of microscopic [[cavitation]] bubbles near the dirty surface. The collapsing bubbles form tiny shockwaves that break up and disperse contaminants on the object's surface. [161] => [162] => ===Ultrasonic disintegration=== [163] => Similar to ultrasonic cleaning, [[Cell (biology)|biological cell]]s including [[bacteria]] can be disintegrated. High power ultrasound produces [[cavitation]] that facilitates particle disintegration or reactions. This has uses in [[Biology|biological science]] for analytical or chemical purposes ([[sonication]] and [[sonoporation]]) and in killing bacteria in sewage. High power ultrasound can disintegrate corn slurry and enhance liquefaction and saccharification for higher ethanol yield in dry corn milling plants.{{cite journal | vauthors = Akin B, Khanal SK, Sung S, Grewell D |title=Ultrasound pre-treatment of waste activated sludge |doi= 10.2166/ws.2006.962 |year=2006 |journal=Water Science and Technology: Water Supply|volume=6|page=35 |issue=6 }}{{cite journal | vauthors = Neis U, Nickel K, Tiehm A |title=Enhancement of anaerobic sludge digestion by ultrasonic disintegration |journal=Water Science and Technology|volume=42|issue=9|page=73|date= November 2000 |doi=10.2166/wst.2000.0174}} [164] => [165] => ===Ultrasonic humidifier=== [166] => The ultrasonic humidifier, one type of [[nebulizer]] (a device that creates a very fine spray), is a popular type of humidifier. It works by vibrating a metal plate at ultrasonic frequencies to nebulize (sometimes incorrectly called "atomize") the water. Because the water is not heated for evaporation, it produces a cool mist. The ultrasonic pressure waves nebulize not only the water but also materials in the water including calcium, other minerals, viruses, fungi, bacteria,{{cite journal | vauthors = Oie S, Masumoto N, Hironaga K, Koshiro A, Kamiya A | title = Microbial contamination of ambient air by ultrasonic humidifier and preventive measures | journal = Microbios | volume = 72 | issue = 292–293 | pages = 161–6 | year = 1992 | pmid = 1488018 }} and other impurities. Illness caused by impurities that reside in a humidifier's reservoir fall under the heading of "Humidifier Fever". [167] => [168] => Ultrasonic humidifiers are frequently used in [[aeroponics]], where they are generally referred to as [[fogger]]s. [169] => [170] => ===Ultrasonic welding=== [171] => In [[ultrasonic welding]] of plastics, high frequency (15 kHz to 40 kHz) low amplitude vibration is used to create heat by way of friction between the materials to be joined. The interface of the two parts is specially designed to concentrate the energy for maximum weld strength. [172] => [173] => ===Sonochemistry=== [174] => {{Main|Sonochemistry}} [175] => Power ultrasound in the 20–100 kHz range is used in chemistry. The ultrasound does not interact directly with [[molecule]]s to induce the chemical change, as its typical wavelength (in the millimeter range) is too long compared to the molecules. Instead, the energy causes [[cavitation]] which generates extremes of temperature and pressure in the liquid where the reaction happens. Ultrasound also breaks up solids and removes [[Passivation (chemistry)|passivating]] layers of [[Chemically inert|inert]] material to give a larger [[surface area]] for the reaction to occur over. Both of these effects make the reaction faster. In 2008, [[Atul Kumar (chemist)|Atul Kumar]] reported synthesis of Hantzsch esters and polyhydroquinoline derivatives via multi-component reaction protocol in aqueous [[micelles]] using ultrasound.{{cite journal | first1 = Kumar | last1 = Atul | first2 = Awatar Maurya | last2 = Ram | year = 2008| title = Efficient Synthesis of Hantzsch Esters and Polyhydroquinoline Derivatives in Aqueous Micelles | url = https://www.organic-chemistry.org/abstracts/lit2/076.shtm | journal = Synlett | volume = 2008 | issue = 6| pages = 883–885 | doi = 10.1055/s-2008-1042908 }} [176] => [177] => Ultrasound is used in [[Liquid-liquid extraction|extraction]], using different frequencies. [178] => [179] => ==Other uses== [180] => When applied in specific configurations, ultrasound can produce short bursts of light in a phenomenon known as [[sonoluminescence]]. This phenomenon is being investigated partly because of the possibility of [[bubble fusion]] (a [[nuclear fusion]] reaction hypothesized to occur during sonoluminescence). [181] => [182] => Ultrasound is used when characterizing particulates through the technique of [[ultrasound attenuation spectroscopy]] or by observing [[electroacoustic phenomena]] or by [[transcranial pulsed ultrasound]]. [183] => [184] => ===Wireless communication=== [185] => Audio can be propagated by [[modulated ultrasound]]. [186] => [187] => A formerly popular consumer application of ultrasound was in television [[remote control]]s for adjusting volume and changing channels. Introduced by [[Zenith Electronics|Zenith]] in the late 1950s, the system used a hand-held remote control containing short rod resonators struck by small hammers, and a microphone on the set. Filters and detectors discriminated between the various operations. The principal advantages were that no battery was needed in the hand-held control box and, unlike [[radio waves]], the ultrasound was unlikely to affect neighboring sets. Ultrasound remained in use until displaced by infrared systems starting in the late 1980s.{{cite book | first = Jeremy G. | last = Butler | title = Television: Critical Methods and Applications | publisher = Routledge | date = 2006 | page = 276 | isbn = 978-0-8058-5415-2 }} [188] => [189] => In July 2015, ''[[The Economist]]'' reported that researchers at the [[University of California, Berkeley]] have conducted ultrasound studies using [[graphene]] [[diaphragm (acoustics)|diaphragms]]. The thinness and low weight of graphene combined with its strength make it an effective material to use in ultrasound communications. One suggested application of the technology would be underwater communications, where radio waves typically do not travel well.{{cite news|date=2015-07-11|title=Acoustic chatter|url=https://www.economist.com/news/science-and-technology/21657353-graphene-may-usher-radios-do-not-use-radio-waves-acoustic-chatter|newspaper=The Economist|publisher=economist.com|archive-url=https://web.archive.org/web/20150724034441/http://www.economist.com/news/science-and-technology/21657353-graphene-may-usher-radios-do-not-use-radio-waves-acoustic-chatter|archive-date=2015-07-24|access-date=2015-07-23|url-status=live}} [190] => [191] => Ultrasonic signals have been used in "audio beacons" for [[cross-device tracking]] of Internet users.{{Cite journal|last=Arp|first=Daniel|title=Privacy Threats through Ultrasonic Side Channels on Mobile Devices|url=https://ieeexplore.ieee.org/document/7961950%E2%80%8B|journal=IEEE European Symposium on Security and Privacy|pages=1–13|via=IEEE Xplore}}{{Cite journal|last=Mavroudis|first=Vasilios|title=On the Privacy and Security of the Ultrasound Ecosystem|url=https://massless.info/images/On_the_Privacy_and_Security_of_the_Ultrasound_Ecos.pdf|journal=Proceedings on Privacy Enhancing Technologies|year=2017|volume=2017|issue=2|pages=95–112|doi=10.1515/popets-2017-0018|s2cid=5068807|via=Sciendo}} [192] => [193] => ==Safety== [194] => Occupational exposure to ultrasound in excess of 120 dB may lead to hearing loss. Exposure in excess of 155 dB may produce heating effects that are harmful to the human body, and it has been calculated that exposures above 180 dB may lead to death.{{cite book|title=Guidelines for the Safe Use of Ultrasound Part II{{Snd}} Industrial & Commercial Applications{{Snd}} Safety Code 24|url=http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/safety-code_24-securite/health-sante-eng.php#a2.2|isbn=978-0-660-13741-4|year=1991|publisher=Health Canada|author1=Part II, industrial|author2=commercial applications|archive-url=https://web.archive.org/web/20130110213842/http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/safety-code_24-securite/health-sante-eng.php#a2.2|archive-date=2013-01-10}} The UK's independent Advisory Group on Non-ionising Radiation (AGNIR) produced a report in 2010, which was published by the UK Health Protection Agency (HPA). This report recommended an exposure limit for the general public to airborne ultrasound sound pressure levels (SPL) of 70 dB (at 20 kHz), and 100 dB (at 25 kHz and above).{{cite book|title=Health Effects of Exposure to Ultrasound and Infrasound|year=2010|publisher=Health Protection Agency, UK.|url=http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1265028759369|author=AGNIR|pages=167–170|access-date=2011-11-16|archive-url=https://web.archive.org/web/20111108194756/http://www.hpa.org.uk/webc/HPAwebFile/HPAweb_C/1265028759369|archive-date=2011-11-08|url-status=live}} [195] => [196] => In [[medical ultrasound]], guidelines exist to prevent inertial cavitation from happening. The risk of inertial cavitation damage is expressed by the [[mechanical index]]. [197] => [198] => == See also == [199] => {{Portal|Medical}} [200] => {{div col|colwidth=22em}} [201] => * [[Acoustic droplet ejection]] [202] => * [[Acoustic emission]] [203] => * [[Bat detector]] [204] => * [[Contrast-enhanced ultrasound]] [205] => * [[Delay-line memory]] [206] => * [[Focused ultrasound-mediated diagnostics]] [207] => * [[Infrasound]] — sound at extremely low frequencies [208] => * [[Isochoic wave|Isochoic]] [209] => * [[Laser ultrasonics]] [210] => * [[Phased array ultrasonics]] [211] => * [[Picosecond ultrasonics]] [212] => * [[Sonomicrometry]] [213] => * [[Sound from ultrasound]] (also known as hypersonic sound) [214] => * [[Surface acoustic wave]] [215] => * [[Ultrasonic motor]] [216] => * [[Ultrasonic attenuation]] [217] => * [[Ultrasound attenuation spectroscopy]] [218] => {{div col end}} [219] => [220] => == References == [221] => {{Reflist|30em}} [222] => [223] => == Further reading == [224] => {{Library resources box [225] => |by=no [226] => |onlinebooks=no [227] => |others=no [228] => |about=yes [229] => |label=Ultrasound}} [230] => {{refbegin}} [231] => * {{cite book | last = Kundu | first = Tribikram | title = Ultrasonic nondestructive evaluation: engineering and biological material characterization | location = Boca Raton, FL | publisher = CRC Press | date = 2004 | isbn = 978-0-8493-1462-9 }} [232] => * {{cite journal | vauthors = Grzesik J, Pluta E | title = High-frequency hearing risk of operators of industrial ultrasonic devices | journal = International Archives of Occupational and Environmental Health | volume = 53 | issue = 1 | pages = 77–88 | year = 1983 | pmid = 6654504 | doi = 10.1007/BF00406179 | bibcode = 1983IAOEH..53...77G | s2cid = 37176293 }} [233] => {{refend}} [234] => [235] => == External links == [236] => [237] => [249] => * [https://web.archive.org/web/20130110213842/http://www.hc-sc.gc.ca/ewh-semt/pubs/radiation/safety-code_24-securite/health-sante-eng.php Guidelines for the Safe Use of Ultrasound]: valuable insight on the boundary conditions tending towards abuse of ultrasound [250] => [251] => {{Acoustics}} [252] => {{Authority control}} [253] => [254] => [[Category:Ultrasound| ]] [255] => [[Category:Acoustics]] [256] => [[Category:Sound]] [] => )
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Ultrasound

Ultrasound is a medical imaging technique that uses high-frequency sound waves to produce images of the inside of the body. It is commonly used to visualize the organs and structures within the abdomen, pelvic region, heart, blood vessels, and other areas.

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It is commonly used to visualize the organs and structures within the abdomen, pelvic region, heart, blood vessels, and other areas. The technique works by sending ultrasound waves into the body through a transducer, which then receives the echoes produced as the waves bounce off structures inside the body. These echoes are then converted into images by a computer, allowing healthcare professionals to diagnose and monitor a wide range of conditions. Ultrasound is considered safe and noninvasive, as it does not involve the use of ionizing radiation like X-rays or CT scans. It is widely used in obstetrics to monitor the development of a fetus during pregnancy and detect any abnormalities. It is also employed in various other medical specialties, including cardiology, gastroenterology, urology, and radiology. In addition to imaging, ultrasound can be used therapeutically for various purposes, such as breaking up kidney stones or delivering heat to specific tissues for therapeutic purposes. This technique, known as ultrasound therapy, is often used in physical therapy and sports medicine. While ultrasound has its limitations, such as difficulty imaging through bones or air-filled areas, it is a versatile and valuable medical tool. It is also portable, relatively low-cost, and does not require complex preparation or recovery periods. The Wikipedia page for ultrasound provides a comprehensive overview of the technique, its history, the different types of ultrasound machines and transducers, as well as its applications in different medical specialties. It also covers the risks and limitations of ultrasound, ongoing research and developments in the field, and related topics such as Doppler ultrasound and contrast-enhanced ultrasound.

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