MSK AcademySound wave
Sound is a mechanical wave that propagates through a medium by transferring energy between particles of matter. Unlike electromagnetic radiation, sound cannot travel in a vacuum; it always requires a material medium, such as air, water, or biological tissues.
From a physical perspective it is a longitudinal wave. The particles of the medium do not move in the direction of propagation but oscillate around their equilibrium position. This oscillation creates alternating regions of compression (increased pressure and particle density) and rarefaction (reduced pressure and particle density) that travel through the medium.
A sound wave can be described by several basic parameters. The most important are frequency, which indicates the number of oscillations per second, and wavelength, the distance between two neighboring points of the same phase of the wave (for example, between two maxima of compression). These parameters are related: at a constant propagation speed, higher frequency corresponds to a shorter wavelength.
In ultrasound imaging, the properties of the sound wave are essential because they determine how ultrasound propagates through biological tissues and how it interacts with tissue interfaces.
In ultrasound imaging, the properties of the sound wave are essential because they determine how ultrasound propagates through biological tissues and how it interacts with tissue interfaces.