Attenuation in soft tissue depends on which property of the sound wave?

• A. Frequency
• B. Amplitude
• C. Speed
• D. Wavelength

Answer: (A)

Attenuation in soft tissue is about how quickly the ultrasound beam loses energy as it travels. In soft tissue, the attenuation coefficient increases with frequency, so higher-frequency waves are absorbed and scattered more readily than lower-frequency waves. Because attenuation scales with frequency, doubling the frequency roughly doubles the energy loss per centimeter, reducing how far the beam can penetrate. The speed and amplitude describe how fast and how strong the wave starts, not how much energy is lost along the path, and wavelength is linked to speed and frequency but isn’t the primary factor driving attenuation. This is why higher frequencies give crisper images but don’t penetrate as deeply, while lower frequencies penetrate deeper with less attenuation.