Which term describes the rate at which the ultrasound beam loses intensity per unit length?

Which term describes the rate at which the ultrasound beam loses intensity per unit length?

• A. Attenuation coefficient
• B. Absorption coefficient
• C. Attenuation rate
• D. Scattering coefficient

Answer: (A)

Attenuation coefficient describes how quickly the ultrasound beam loses intensity per unit length as it travels through tissue. It accounts for the combined effects of absorption (energy converted to heat) and scattering (energy redirected out of the beam). Because attenuation increases with frequency, higher-frequency beams and longer paths lead to more rapid intensity decay, which is why deeper signals appear weaker. The absorption coefficient only measures losses due to absorption, and the scattering coefficient only measures losses due to scattering, but neither alone describes the total rate of attenuation. Attenuation coefficient, usually expressed in dB/cm or nepers/cm, is the standard term for the overall rate of intensity loss per unit length.

Attenuation coefficient describes how quickly the ultrasound beam loses intensity per unit length as it travels through tissue. It accounts for the combined effects of absorption (energy converted to heat) and scattering (energy redirected out of the beam). Because attenuation increases with frequency, higher-frequency beams and longer paths lead to more rapid intensity decay, which is why deeper signals appear weaker. The absorption coefficient only measures losses due to absorption, and the scattering coefficient only measures losses due to scattering, but neither alone describes the total rate of attenuation. Attenuation coefficient, usually expressed in dB/cm or nepers/cm, is the standard term for the overall rate of intensity loss per unit length.