What happens to power as the ultrasound beam propagates through the body?

What happens to power as the ultrasound beam propagates through the body?

• A. Increases
• B. Stays the same
• C. Decreases
• D. Oscillates

Answer: (C)

As the ultrasound beam moves through tissue, its power (intensity) decreases because energy is lost to attenuation. Tissue absorbs part of the sound energy and scatters or redirects some of it away from the forward path. Higher frequencies are attenuated more, so energy reaching deeper tissues drops even more quickly. The energy lost from the forward beam becomes heat in the tissue, so less power remains to continue deeper or to produce echoes. That’s why imaging systems use gain adjustments to compensate for this predictable loss with depth. In short, the further the beam travels, the more it is attenuated, so the power decreases.

As the ultrasound beam moves through tissue, its power (intensity) decreases because energy is lost to attenuation. Tissue absorbs part of the sound energy and scatters or redirects some of it away from the forward path. Higher frequencies are attenuated more, so energy reaching deeper tissues drops even more quickly. The energy lost from the forward beam becomes heat in the tissue, so less power remains to continue deeper or to produce echoes. That’s why imaging systems use gain adjustments to compensate for this predictable loss with depth. In short, the further the beam travels, the more it is attenuated, so the power decreases.