In ultrasound, which parameter describes the energy delivered per unit area?

In ultrasound, which parameter describes the energy delivered per unit area?

• A. Intensity
• B. Frequency
• C. Phase
• D. Attenuation

Answer: (A)

Energy delivered per unit area is described by intensity. Intensity is the amount of energy crossing a given area each second, essentially power divided by beam area. In ultrasound, this tells you how much energy the tissue at the surface (or a specific plane) is exposed to per unit area, which is why intensity is the key measure for exposure and safety. Frequency refers to how fast the wave oscillates and affects resolution and penetration, not how much energy is deposited per area. Phase is about the timing of the wave’s cycles, not the energy delivery. Attenuation describes how energy diminishes as it travels through tissue due to absorption and scattering, which is about energy loss along the path rather than the energy delivered to a particular area per unit time.

Energy delivered per unit area is described by intensity. Intensity is the amount of energy crossing a given area each second, essentially power divided by beam area. In ultrasound, this tells you how much energy the tissue at the surface (or a specific plane) is exposed to per unit area, which is why intensity is the key measure for exposure and safety. Frequency refers to how fast the wave oscillates and affects resolution and penetration, not how much energy is deposited per area. Phase is about the timing of the wave’s cycles, not the energy delivery. Attenuation describes how energy diminishes as it travels through tissue due to absorption and scattering, which is about energy loss along the path rather than the energy delivered to a particular area per unit time.