Bone absorbs ultrasound energy to a large extent which results in substantial ______.

• A. Reflection
• B. Refraction
• C. Diffraction
• D. Attenuation

Answer: (D)

Attenuation is the decrease in ultrasound intensity as it travels through a medium. Bone has a high attenuation coefficient because it’s dense and mineralized, so a large portion of the energy is absorbed (and some is scattered) as it propagates. That absorption converts energy into heat and reduces the transmitted signal, leading to substantial attenuation.

Reflections occur when energy bounces back at interfaces due to impedance differences; refraction is a change in direction from speed differences between media; diffraction is bending around obstacles. The statement specifically describes energy loss inside the bone, not energy redirected or reflected, so attenuation is the best fit.