As frequency increases, what happens to attenuation in soft tissue?

As frequency increases, what happens to attenuation in soft tissue?

• A. Increases
• B. Decreases
• C. Remains the same
• D. Varies unpredictably

Answer: (A)

Attenuation in soft tissue increases with frequency because energy loss per unit distance (made up of absorption and scattering) grows as waves become more oscillatory. In soft tissue, the attenuation coefficient is roughly proportional to frequency (about 0.5 dB/cm/MHz), so doubling the frequency roughly doubles the attenuation per centimeter. This is why higher-frequency ultrasound yields better resolution but less penetration. Therefore, the correct idea is that attenuation increases as frequency rises.

Attenuation in soft tissue increases with frequency because energy loss per unit distance (made up of absorption and scattering) grows as waves become more oscillatory. In soft tissue, the attenuation coefficient is roughly proportional to frequency (about 0.5 dB/cm/MHz), so doubling the frequency roughly doubles the attenuation per centimeter. This is why higher-frequency ultrasound yields better resolution but less penetration. Therefore, the correct idea is that attenuation increases as frequency rises.