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No effect was detected on listeners in the study when only the ultrasonic [14] (frequencies higher than 24 kHz) portion of the test material was played for test subjects; the demonstrated effect was only present when comparing full-bandwidth to bandwidth-limited material.
Standard ultrasound medical devices may also be used in some applications. Measurement of the acoustics used in sonoporation is listed in terms of mechanical index , which quantifies the likelihood that exposure to diagnostic ultrasound will produce an adverse biological effect by a non-thermal action based on pressure.
Exposure to ELF waves can induce an electric current. Because the human body is conductive, electric currents and resulting voltages differences typically accumulate on the skin but do not reach interior tissues. [22] People can start to perceive high-voltage charges as tingling when hair or clothing in contact with the skin stands up or ...
Photoacoustic imaging or optoacoustic imaging is a biomedical imaging modality based on the photoacoustic effect.Non-ionizing laser pulses are delivered into biological tissues and part of the energy will be absorbed and converted into heat, leading to transient thermoelastic expansion and thus wideband (i.e. MHz) ultrasonic emission.
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.
A curvilinear array ultrasonic transducer for use in medical ultrasonography Inside construction of a Philips C5-2 128 element curved array ultrasound sensor. Ultrasonic transducers and ultrasonic sensors are devices that generate or sense ultrasound energy. They can be divided into three broad categories: transmitters, receivers and transceivers.
One possible way is the use of an implantable transcranial Doppler device "operatively connected to a drug delivery system". [7] Battery-powered, it would use an RF link to a portable computer running a spectral analysis routine together with input from an oximeter (monitoring the degree of blood oxygenation, which a stroke might impair) to ...
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.