Propagation speed ____ affect attenuation of the sound beam.

Propagation speed ____ affect attenuation of the sound beam.

• A. Does not
• B. Does
• C. Sometimes
• D. Always

Answer: (A)

Attenuation describes how the beam’s intensity decreases as it travels, mainly due to absorption and scattering in the tissue. These processes depend on the tissue’s composition and the ultrasound frequency, not on how fast the wave propagates. The speed of sound sets the wavelength and the time it takes to reach depth, but it does not change how much energy is absorbed per unit distance. So propagation speed does not affect attenuation. The speed does influence time-of-flight and boundary reflections due to impedance differences, but inside a single medium, attenuation is governed by absorption and scattering, not speed.

Attenuation describes how the beam’s intensity decreases as it travels, mainly due to absorption and scattering in the tissue. These processes depend on the tissue’s composition and the ultrasound frequency, not on how fast the wave propagates. The speed of sound sets the wavelength and the time it takes to reach depth, but it does not change how much energy is absorbed per unit distance. So propagation speed does not affect attenuation. The speed does influence time-of-flight and boundary reflections due to impedance differences, but inside a single medium, attenuation is governed by absorption and scattering, not speed.