Ultrasound Database •
The source level is the acoustic power (sound pressure) in decibels (dB) referenced to 1.0 microPascal measured at 1 meter from the sound source transmitted through a unit area in a specified direction. The unit of intensity is watt per square meter, but source level is commonly given as a relative intensity in dB. •
(SA) The spatial average intensity is the acoustic power within the beam, divided by the beam area.
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(I-SPTA) Spatial peak time averaged intensity is the measure most associated with temperature rise. See also Thermal Effect, and Time Average Intensity. •
The spatial resolution describes the smallest distance between two points in the object that can be distinguished as separate details in the image, generally indicated as a length or a number of black and white line pairs per mm (lp/mm). In ultrasound imaging, the spatial resolution means how closely two reflecting tissues - or scattering regions, can be to one another while they can be identified as different reflectors.
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