What pulsed mode setting is recommended when using ultrasound over implanted materials?

• A. Continuous mode only
• B. 10% or less
• C. 90% or more
• D. 50% or less

Answer: (D)

The main idea is controlling heat buildup when ultrasound is applied over implanted materials. Pulsed delivery keeps energy on only part of the time, so the average energy that tissues absorb is lower. The duty cycle—how long the ultrasound is on versus off—drives this. A duty cycle of fifty percent or less means energy is on half the time or less, which reduces heating risk at the implant site while still allowing the mechanical effects of ultrasound to aid healing. Higher duty cycles or continuous mode increase heat and can damage surrounding tissue around implants, so they’re avoided. If you’re unsure, starting at fifty percent or less provides a safe, effective balance; you can adjust downward if any heat or discomfort is noted.