Pulsed ultrasound intensities are associated with which effect at 1.5-2 W/cm2?

Pulsed ultrasound intensities are associated with which effect at 1.5-2 W/cm2?

• A. Nonthermal
• B. Thermal
• C. Mechanical
• D. Electrical

Answer: (A)

Pulsed ultrasound delivers energy in bursts with off time, so the average energy deposited in tissue stays relatively low. This minimizes heating, making nonthermal effects the primary outcome at 1.5–2 W/cm2. Those nonthermal effects are mainly mechanical in nature—cavitation, microstreaming, and enhanced cellular activity—that aid healing without significant temperature rise. If the treatment were continuous or at a higher duty cycle, thermal effects would be more likely, but in pulsed mode the dominant effect is nonthermal.

Pulsed ultrasound delivers energy in bursts with off time, so the average energy deposited in tissue stays relatively low. This minimizes heating, making nonthermal effects the primary outcome at 1.5–2 W/cm2. Those nonthermal effects are mainly mechanical in nature—cavitation, microstreaming, and enhanced cellular activity—that aid healing without significant temperature rise. If the treatment were continuous or at a higher duty cycle, thermal effects would be more likely, but in pulsed mode the dominant effect is nonthermal.