Refraction
Citation, DOI, disclosures and article data
At the time the article was created Patricia O'Gorman had no recorded disclosures.
View Patricia O'Gorman's current disclosuresAt the time the article was last revised Henry Knipe had the following disclosures:
- Micro-X Ltd, Shareholder (past)
These were assessed during peer review and were determined to not be relevant to the changes that were made.
View Henry Knipe's current disclosures- Snell's law
- Snell law
Refraction of a sound wave occurs if it travels between tissues with different propagation speeds. As the incident pulse or returning echo strikes an interface of different density or elasticity and therefore a different propagation speed, the direction of the wave changes according to Snell’s law 1 :
- sin θ1/sinθ2 = c1/c2
Where:
- sin θ1 = incident angle of the sound wave at the interface
- sin θ2 = refraction angle of the sound wave in the new medium
- c1 = propagation speed in the initial medium
- c2 = propagation speed in the new medium
Ultrasound machines assume all pulsed waves and returning echoes travel along a direct path, therefore refraction can cause refraction artifact 2 .
References
- 1. Carol M. Rumack. Diagnostic Ultrasound. (2011) ISBN: 9780323053976 - Google Books
- 2. Feldman M, Katyal S, Blackwood M. US Artifacts. Radiographics. 2009;29(4):1179-89. doi:10.1148/rg.294085199 - Pubmed
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