Therapeutic ultrasound intensities are expressed in W/cm2 and range from

• A. 0.01-0.1 W/cm2.
• B. 0.25-2.0 W/cm2.
• C. 5-10 W/cm2.
• D. 10-15 W/cm2.

Answer: (B)

Intensities in therapeutic ultrasound refer to the energy delivered per unit area, measured in watts per square centimeter (W/cm^2). In rehabilitation settings, we use relatively low to moderate intensities to produce mild heating and beneficial mechanical effects without risking tissue damage. The typical clinically used range is about 0.25 to 2.0 W/cm^2. This range covers the level needed to heat deeper tissues (with continuous mode) or to elicit non-thermal effects when pulsed, while staying within safe, comfortable limits.

Values much lower, like 0.01 to 0.1 W/cm^2, generally don’t produce meaningful therapeutic heating or mechanical effects. Values much higher, such as 5–10 or 10–15 W/cm^2, are outside standard therapeutic rehab usage and can cause excessive heating or tissue injury, and are reserved for other high-intensity applications.