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Ultrasound is sound with frequencies greater than 20 kilohertz. [1] This frequency is the approximate upper audible 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.
[9] [10] During emission of 22-kHz calls, juveniles and adults are often exhibiting freezing behaviour and experiencing an increase in heart rate and blood pressure. [1] Since 22-kHz calls are emitted in response to unpleasant situations and noxious stimuli, it has been thought that these calls serve two functions: reflecting anxiety, and ...
This method of medical ultrasound therapy can be used for various types of pain relief and physical therapy. In physics, the term "ultrasound" [1] applies to all acoustic energy with a frequency above the audible range of human hearing. The audible range of sound is 20 hertz – 20 kilohertz. Ultrasound frequency is greater than 20 kilohertz.
For frequencies of ultrasound from 25 to 50 kHz, a guideline of 110 dB had been recommended by Canada, Japan, the USSR, and the International Radiation Protection Agency, and 115 dB by Sweden [24] in the late 1970s to early 1980s, but these were primarily based on subjective effects. The more recent OSHA guidelines above are based on ACGIH ...
Logarithmic chart of the hearing ranges of some animals [1] [2] Hearing range describes the frequency range that can be heard by humans or other animals, though it can also refer to the range of levels. The human range is commonly given as 15.000 to 20,000 Hz, although there is considerable variation between individuals, especially at high ...
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Ultrasound energy, simply known as ultrasound, is a type of mechanical energy called sound characterized by vibrating or moving particles within a medium. Ultrasound is distinguished by vibrations with a frequency greater than 20,000 Hz, compared to audible sounds that humans typically hear with frequencies between 20 and 20,000 Hz.
Medical ultrasound includes diagnostic techniques (mainly imaging techniques) using ultrasound, as well as therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal body structures such as tendons, muscles, joints, blood vessels, and internal organs, to measure some characteristics (e.g., distances and velocities) or to generate an informative audible sound.