Talk:Ultrasound
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This articles needs one or more sources, added tag.--FloNight 23:38, 26 November 2005 (UTC)
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[edit] Why can't humans hear ultrasound?
Why can not human being hear sounds more than 20 kilohertz??
Because above 20,000 Hertz (vibrations per second) the waves are too small and fast for the inner ear to transmit the vibrations. 20,000 Hertz is the typical upper limit of hearing, there may be individuals who can detect some frequencies slightly above this range, but not much higher. DuBose 14:06, 11 November 2005 (UTC)
It should perhaps also be noted that this limit is lower for many persons - it decreases with age, and it is also decreased by repeated exposure to high-intensity sounds of lower frequencies (loud music being a common example). Osquar F 12:33, 5 December 2006 (UTC)
[edit] Sonography
Does anyone know why medical sonography uses a typical frequency of 1 to 10 MHz. Why not higher? Are there any constraints on this?
-- I believe this is due to regulations on transmitted power - higher the frequency, the higher the energy in the transmission. To prevent localized heating, the transmitted energy (and thus the frequency) are limited. Also, the upper limit is more like 15MHz, IIRC, although that's flexible depending on the specific application.
-- In addition, attenuation of an ultrasound beam is proportional to its frequency, which means that a 10MHz medical imaging beam can only penetrate around 3cm at "safe" power levels. Only very superficial structures can be scanned in this way. Higher frequencies can be used in small children where the size and relative depths of structures of interest are smaller, and can also be used in adults in situations where a modified probe can be put inside the body. Examples of this are trans-esophageal echocardiography, transvaginal sonography and intravascular ultrasound imaging.
You seem to be changing every use of "ultrasonography" with "sonography". I wish you'd discussed this on the relevant talk pages first. I think the correct term is "ultrasonography" if the test is called "an ultrasound". I've changed it back for now. Please provide some support for your changes. JFW | T@lk 14:32, 11 November 2005 (UTC)
If you think the article medical ultrasonography should be called sonography instead, please do not create a duplicate page but suggest a move on the former page. JFW | T@lk 14:37, 11 November 2005 (UTC) Retrieved from "http://en.wikipedia.org/wiki/User_talk:DuBose"
I do disagree with the term ultrasonography and ultrasound in this context. There is a historical place for the term ultrasound; however, ultrasound is a term of physics meaning frequencies above human hearing; you obviously know this. Ultrasound is not unique to medical imaging. Many use “ultrasound” for medical and non-medical purposes. Physical Therapists use it for deep heat, Dental Hygienist use it to clean teeth, Iron Workers use it for non-destructive testing, and jewelers use it to clean rings and watches. Only sonographers use ultrasonic energy to create medical images. Sonography, sonographer, and sonographic were coined 30 years ago to specifically refer to this type of medical imaging. Ultrasonography is unnecessarily long, pretentious, and redundant because the “ultra” goes without saying. Sonography is simple, unique, and specific to the profession.
While ultrasound predates the term sonography and its derivatives, sonography is much more consistent with older medical nomenclature such as radiography. And while we use ultrasonic energy to create these images, to refer to the technique or image as an “ultrasound” is analogous to referring to a photograph as a “light”… photographs are reflected light.
Sonography, Sonographer, & Sonographic are well accepted and because they are unique to the profession are more specific to it. There are ample examples of the acceptance of these terms:
- http://www.ARDMS.org
- http://www.SDMS.org
- http://www.bls.gov/oco/ocos273.htm
- http://www.sonoworld.com/
Definitions of sonography on the Web: • A imaging technique for visualizing the growth of ovarian follicles during infertility therapy. http://www.infertilitycentral.com/fertility/infertility-glossary,6.html • use of sound to form images eg ultrasound scanning http://www.nutrition-matters.co.uk/misc/glossary.htm • An imaging test which sends sound waves to and receives them back from an organ to create an image of that organ. http://www8.utsouthwestern.edu/utsw/cda/dept22047/files/144495.html • using the reflections of high-frequency sound waves to construct an image of a body organ (a sonogram); commonly used to observe fetal growth or study bodily organs wordnet.princeton.edu/perl/webwn DuBose 22:03, 11 November 2005 (UTC)
- This discussion should be conducted on talk:medical ultrasonography and not here. JFW | T@lk 01:50, 13 November 2005 (UTC)
[edit] ultrasound communication for underwater
Does anyone know anything about the communication devices used by divers?--Gbleem 01:28, 22 November 2005 (UTC)
" to refer to the technique or image as an “ultrasound” is analogous to referring to a photograph as a “light”… photographs are reflected light."
Is this not what people do when they call a light-produced image a "photo"?
[edit] Ultrasound definition and Principles
[edit] Principles
The principles of ultrasound are the same irrespective of the application. Several contributors have defined ultrasound in terms of its use in medicine, with little more than a cursory nod toward it's use in industry. Although in modern times the use of ultrasound is much more widespread in medicine and thus more familiar to the public at large, it is in a comparitively narrow field and uses a small range of frequencies, in the MHz range, which are suited to human tissue and bone. In industrial nondestructive testing (NDT) the uses are far more varied and the range of frequencies varies from 100's of Khz up to many Ghz. Such applications include, crack detection and sizing, bond testing, material evaluation and ultrasonic microscopy. Hardware ranges from single probe in pulse-echo mode - ie sending and receiving its own pulse, thru inspection systems used in the oil and gas industry containing many probes up to multi-element arrays capable of producing a real-time image of the object under test (herein lies the parallel with medical imaging).
[edit] Definition
Quite correctly, ultrasound is defined as "above the frequency at which the average human can hear", i.e. approximately 16khz but then the rather bold statement is made that because Bats and certain other animals' threshold is higher, "they can hear Ultrasound". This is very misleading. Admittedly, certain species of bat can hear up to 160 khz but this is a minute proportion of the full spectrum of Ultrasound, which as I have already said is well into the Ghz range.
Ghz range is not, and can not be used in industrial applications; inspections of metals. The grain structure of the material becomes obvious far below the Ghz range. The sound beam would not have the penetrating power to accurately allow for cogent interpretation. 5 Mhz is capable of sizing a defect to 0.5 mm. Even 10 Mhz is seldom used.
It is important to distinguish between industrial application of Ultrasond and the full spectrum to which the term Ultrasound can be applied. You cannot claim that "5MHz can size a defect to 0.5mm", without specifying the material, the grain size and the technique being used.
Ultrasound is indeed used up to the range of GHz in Acoustic microscopes. It is used well into the 20 and 30 MHz range for example in bond testing between Aluminium substrates.
May I suggest some slight changes to the ultrasound page to encompass the various interpretations of the word "ultrasound". I think the opening section is looking good - it states the technical definition of the word, and briefly covers the various applications. But then the rest of the article assumes ultrasound == sonography, which is at odds with the opening. Here's my suggestion:
The opening remains in close to its current form, with technical definition and common applications/interpretations.
The next section is "From sound to image (sonography)" which includes dangers, producing, receiving, displaying, all covered in a scientific manner. Then a link is provided to the "medical ultrasonography" page for more practice perspective info.
Then a section is added "From sound to graph (ultrasound testing)" which covers the NDT/NDE applications of ultrasound, in a scientific manner. I'm happy to provide a first draft for this section.
Perhaps the baby in womb picture could be moved to "medical ultrasonography" and a frequency spectrum graph inserted instead?
LightYear 00:02, 24 January 2006 (UTC)
[edit] ESWL is not Ultrasound
Extracorporeal shock wave lithotripsy is not an ultrasound application. Seejyb 23:54, 14 November 2006 (UTC)
