Increasing protein content gives increasing ______ for ultrasound beam.

• A. Absorption
• B. Reflection
• C. Transmission
• D. Scattering

Answer: (A)

The amount of ultrasound energy absorbed in tissue grows with greater protein content. Absorption is the part of attenuation where acoustic energy is converted to heat through molecular interactions, and more protein provides more of these absorption pathways. This is different from reflection, which depends mostly on impedance differences at interfaces, and from scattering, which hinges on microscopic tissue structure. Transmission simply reflects what remains after attenuation, so it decreases as absorption increases. Therefore, increasing protein content raises the absorption of the ultrasound beam.