Which output mode is associated with nonthermal effects in therapeutic ultrasound?

Which output mode is associated with nonthermal effects in therapeutic ultrasound?

• A. Pulsed output
• B. Continuous output
• C. Both
• D. Neither

Answer: (A)

Nonthermal effects come from the mechanical interactions of the ultrasound waves—things like cavitation, microstreaming, and increased membrane permeability—rather than from heating the tissue. Pulsed delivery provides energy in short bursts with off times, which lowers the average intensity and minimizes temperature rise while still producing those mechanical effects. Continuous delivery deposits energy steadily, increasing tissue temperature and producing thermal effects. So, pulsed output is the mode associated with nonthermal effects.

Nonthermal effects come from the mechanical interactions of the ultrasound waves—things like cavitation, microstreaming, and increased membrane permeability—rather than from heating the tissue. Pulsed delivery provides energy in short bursts with off times, which lowers the average intensity and minimizes temperature rise while still producing those mechanical effects. Continuous delivery deposits energy steadily, increasing tissue temperature and producing thermal effects. So, pulsed output is the mode associated with nonthermal effects.