In ultrasound, what is absorption primarily responsible for during imaging?

Absorption in ultrasound refers to the process where sound energy is transformed into heat as it travels through a medium, such as tissue. This phenomenon is predominantly influenced by the frequency of the ultrasound wave and the properties of the medium. Higher frequency ultrasound waves typically experience greater absorption, which leads to more energy being converted to heat. This conversion of sound energy into thermal energy is a key factor in determining the depth of penetration of ultrasound waves; as absorption occurs, less energy is available to reflect back and form images, especially at greater depths.

While absorption plays a role in imaging, it does not enhance image contrast or reduce noise significantly; instead, increased absorption can contribute to image degradation because less reflected sound returns to the transducer. Scattering, on the other hand, refers to how sound waves are redirected in various directions from small structures, a process distinct from absorption. Therefore, absorption's primary role is indeed the conversion of sound energy to heat within the medium, impacting both imaging quality and depth of penetration.