ARDMS Ultrasound Physics & Instrumentation Practice Exam

Absorption, reflection, and scattering are mechanisms of what phenomenon in ultrasound?

1. Refraction

2. Attenuation

3. Echoing

4. Transmission

The correct answer is: Attenuation

Absorption, reflection, and scattering are all mechanisms that contribute to the phenomenon of attenuation in ultrasound. Attenuation refers to the gradual loss of intensity as an ultrasound beam travels through a medium. As ultrasound waves propagate, they encounter various tissues and interfaces, leading to several mechanisms that can diminish the strength of the wave. - Absorption occurs when the energy from the ultrasound waves is absorbed by the tissues, often converted into heat, reducing the wave’s intensity. - Reflection happens when the ultrasound wave encounters a boundary between two different tissues; part of the wave reflects back, which can lead to a reduction in the amount of sound energy continuing forward. - Scattering is the process in which the ultrasound waves are reflected in multiple directions upon interacting with small structures or irregularities within the tissue, leading to further dispersion and loss of intensity. Together, these mechanisms result in a decrease in the amplitude of the ultrasound signal as it penetrates deeper into the tissue. Understanding attenuation is crucial for interpreting ultrasound images and determining appropriate settings and techniques for optimal imaging results.