Does intensity change as sound propagates through the body?

Does intensity change as sound propagates through the body?

• A. No
• B. Yes, changes
• C. Only in dense tissue
• D. Not at all in soft tissue

Answer: (B)

As sound travels through the body, its intensity changes because part of the energy is lost along the way through attenuation. Attenuation comes from absorption (tissues convert acoustic energy to heat), scattering (energy is redirected out of the main beam), and geometric spreading (the beam divides over a larger area with distance). Higher frequencies attenuate more quickly, so the intensity drops more with depth at higher frequencies. Because these processes occur in all tissues, the beam’s intensity is not constant as it propagates. Dense tissues like bone cause larger losses, but soft tissue still reduces intensity, and there isn’t a single tissue type where attenuation doesn’t occur.

As sound travels through the body, its intensity changes because part of the energy is lost along the way through attenuation. Attenuation comes from absorption (tissues convert acoustic energy to heat), scattering (energy is redirected out of the main beam), and geometric spreading (the beam divides over a larger area with distance). Higher frequencies attenuate more quickly, so the intensity drops more with depth at higher frequencies. Because these processes occur in all tissues, the beam’s intensity is not constant as it propagates. Dense tissues like bone cause larger losses, but soft tissue still reduces intensity, and there isn’t a single tissue type where attenuation doesn’t occur.