Which combination best describes typical LIPUS parameters?

• A. intensity <0.1 W/cm2; 20% duty cycle; 20 min daily
• B. intensity >0.5 W/cm2; 50% duty cycle; 60 min daily
• C. intensity <0.1 W/cm2; 50% duty cycle; 10 min daily
• D. intensity >1 W/cm2; 20% duty cycle; 20 min daily

Answer: (A)

Low-intensity pulsed ultrasound delivers energy in very small bursts to stimulate tissue without causing heating. The typical LIPUS protocol uses a low intensity, a low duty cycle, and a short daily duration to achieve non-thermal mechanical effects that support healing. An intensity under 0.1 W/cm2 keeps energy in a safe, non-thermal range. A duty cycle around 20% means the ultrasound is on only part of the time, preserving the non-thermal nature while still providing stimulation. About 20 minutes per day offers enough exposure to trigger cellular responses without excessive energy delivery. The other options push intensity higher or extend treatment time or duty cycle, which deviates from standard LIPUS practice and increases heating risk or duration beyond typical protocols.