Attenuation is composed of which components?

• A. Absorption, Reflection, Scattering
• B. Absorption, Refraction, Diffraction
• C. Reflection, Diffraction, Refraction
• D. Absorption, Reflection, Refraction

Answer: (A)

Attenuation is the loss of ultrasound energy as it travels through tissue. The two main mechanisms behind this loss are absorption, where energy is transformed into heat, and scattering, where energy is redirected out of the forward beam. Refraction and diffraction describe changes in the beam’s path, not a reduction in energy itself, and reflection is energy that returns back toward the transducer at interfaces, forming echoes rather than continuing forward. So, the core components you should recognize for attenuation are absorption and scattering. The option that lists these (along with reflection) matches the idea that forward energy decreases due to absorption and scattering, with reflection being a related phenomenon that contributes to energy that is not observed in the forward beam.