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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.
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.
Low-intensity pulsed ultrasound (LIPUS) is a technology that can be used for therapeutic purposes. It exploits low intensity and pulsed mechanical waves in order to induce regenerative and anti-inflammatory effects on biological tissues, such as bone, [ 1 ] cartilage, and tendon. [ 2 ]
Laser ultrasonics is a contactless ultrasonic inspection technique based on excitation and ultrasound measurement using two lasers. A laser pulse is directed onto the sample under test and the interaction with the surface generates an ultrasonic pulse that propagates through the material.
Since the pulse from each transducer is progressively delayed going up the line, each transducer emits its pulse after the one below it. This results in a beam of sound waves emitted at an angle (θ) to the array. By changing the pulse delays, the computer can scan the beam of ultrasound in a raster pattern across the tissue.
[4] [5] With each pulse that comes in contact with tissue, a PA signal in the form of an ultrasound wave is produced. This ultrasound wave propagates through the tissue until it reaches an ultrasound transducer to produce an a-line. The maximum amplitude of each a-line is extracted and its value is plotted on a time vs amplitude graph producing ...
The disadvantage of pulsed Doppler is that the measurements can suffer from aliasing. The terms Doppler ultrasound and Doppler sonography have been accepted to apply to both pulsed and continuous Doppler systems, despite the different mechanisms by which the velocity is measured. [citation needed] There are no standards for displaying color ...
As an ultrasound acoustic wave cannot propagates through the compressive tissue, such as rubber, human tissues part of it and the ultrasound energy will be turned to converted as heat, with focused beams, a very small region of heating can be achieved the part of shallow deep in tissues (usually on the order of 2~3 millimeters).