RIU 320 Lecture Notes - Lecture 30: Diffuse Reflection, Sound, Ung County
6 May 2020
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Document Summary
Diffuse reflection, most interfaces in the body are not smooth, but have some irregularities. When a wave reflects off an irregular surface, it radiates in more than one direction. Scattering: random redirection of sound in many directions. Scattering is directly related to frequency: rayleigh scattering, special form of scattering that occurs when the structure"s dimensions are much smaller than the beam"s wavelength . Rayleigh scattering redirects the sound wave equally in all directions, in clinical imaging, the interaction of ultrasound and red blood cells results in this scattering: rayleigh scattering increases dramatically with increasing frequency. The scattering is related to frequency raised to the fourth power: when frequency doubles, rayleigh scattering is 16 times greater, ray scatt= freq^4. Summary: reflection and scattering: what is the significance of attenuation in diagnostic sonography, higher frequency sound waves produce shorter pulses, which usually create more accurate images.
