notes from lecture 1 Flashcards
how fast does sound travel through soft tissue?
1540 metres/ second (remeber this is c in the equation)
on average how fast can sound waves travel through the body?
15/40 metres per second. This is also known as the average wave velocity.
explain the interaction of ultrasound with tissues?
absorption, reflection, scattering and refraction.
what roughly is the pulse reptition frequency?
3-5 pulses per unit time
define velocity
how far the wave form went in and how long it takes for them to reflect back
sound waves involve…..
propagation of compression and rarefractions through a material medium, and that they are longitudinal as opposed to transverse waves.
what terms help describe the US wave?
a. medium particle behaviours
b. medium pressure variations
what does the wave velocity (c) represent?
the velocity at which a sound disturbance propagates through a medium
whats the average wave velocity in steel, human tissue, water and air?
6000ms-1
1540ms-1
1490ms-1
340ms-1
what are the two properties of a medium which control the magnitude of sound wave velocity in them?
the mediums elasticity. how quickly and effectively a medium regains its shape following a deformation. a measure of a mediums stiffness.
what is velocity?
the speed of something in a given direction
what is the process of absorption?
some of the potential energy (the energy held by an object because of its position) contained in the US wave is degraded to heat energy and dissipated in the medium.
absorption increases with……
ultrasound frequency
