Bone will become damaged if hit by ultrasound because

Bone will become damaged if hit by ultrasound because

• A. The beam is so dense
• B. The beam is too diffuse
• C. The tissue is resistant
• D. The energy is too low

Answer: (A)

The concept here is that tissue damage from ultrasound depends on how much energy is delivered per area — the energy density — and how that energy is absorbed by the tissue. Bone is much more capable of absorbing ultrasound energy than soft tissue because of its higher acoustic impedance and attenuation. When the beam is very dense, a lot of energy is deposited into the bone, causing heating and potential mechanical stress. That localized energy buildup can lead to damage if the exposure is high enough or lasts too long. If the beam were too diffuse, the energy would be spread out over a larger area, reducing the amount deposited in any one spot and making damage less likely. Saying the tissue is resistant doesn’t explain why energy deposition would cause damage, and energy that is too low simply can’t cause injury.

The concept here is that tissue damage from ultrasound depends on how much energy is delivered per area — the energy density — and how that energy is absorbed by the tissue. Bone is much more capable of absorbing ultrasound energy than soft tissue because of its higher acoustic impedance and attenuation. When the beam is very dense, a lot of energy is deposited into the bone, causing heating and potential mechanical stress. That localized energy buildup can lead to damage if the exposure is high enough or lasts too long.

If the beam were too diffuse, the energy would be spread out over a larger area, reducing the amount deposited in any one spot and making damage less likely. Saying the tissue is resistant doesn’t explain why energy deposition would cause damage, and energy that is too low simply can’t cause injury.