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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.
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.
The first large scale application of ultrasound was around World War II. Sonar systems were being built and used to navigate submarines. It was realized that the high intensity ultrasound waves that they were using were heating and killing fish. [20] This led to research in tissue heating and healing effects.
Further applications include: humidifiers, sonar, medical ultrasonography, burglar alarms and non-destructive testing. Systems typically use a transducer that generates sound waves in the ultrasonic range, above 20 kHz, by turning electrical energy into sound, then upon receiving the echo turn the sound waves into electrical energy which can be ...
Approximate frequency ranges corresponding to ultrasound, with rough guide of some applications. Ultrasound is sound waves with frequencies higher than 20,000 Hz. Ultrasound is not different from audible sound in its physical properties, but cannot be heard by humans. Ultrasound devices operate with frequencies from 20 kHz up to several gigahertz.
Today, ultrasound waves may be detected optically by a variety of techniques. Most techniques use continuous or long pulse (typically of tens of microseconds) lasers but some use short pulses to down convert very high frequencies to DC in a classic pump-probe configuration with the generation.
Animation showing the principle of an ultrasonic scanner used in medical ultrasonic imaging. It consists of a beamforming oscillator (TX) that produces an electronic signal consisting of pulses of sine waves oscillating at an ultrasonic frequency, which is applied to an array of ultrasonic transducers (T) in contact with the skin surface that convert the electric signal into ultrasonic waves ...
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.