Therapeutic Ultrasound is best defined as which of the following?

• A. Acoustic energy delivered at low frequency
• B. Electrical energy delivered at high frequency
• C. Mechanical vibrations at low frequency
• D. Acoustic energy delivered at high frequency

Answer: (D)

Therapeutic ultrasound relies on acoustic energy delivered to tissues as high-frequency sound waves. The frequency used is in the megahertz range, which allows targeted heating and bioeffects within tissues. It is the acoustic energy itself, not electrical energy, that interacts with tissue, and the defining feature is the high-frequency nature of those sound waves.