For continuous ultrasound, the main effect is?

For continuous ultrasound, the main effect is?

• A. Thermal
• B. Nonthermal
• C. Mechanical only
• D. Chemical changes

Answer: (A)

Continuous ultrasound delivers energy without interruption, so it produces a sustained rise in tissue temperature. That heating is the dominant therapeutic effect, helping to increase blood flow, tissue extensibility, and pain relief. The nonthermal effects, such as cavitation and microstreaming, are more associated with pulsed ultrasound where energy is delivered in bursts and allows cooling between pulses. Chemical changes are not the primary goal of standard therapeutic ultrasound in this context.

Continuous ultrasound delivers energy without interruption, so it produces a sustained rise in tissue temperature. That heating is the dominant therapeutic effect, helping to increase blood flow, tissue extensibility, and pain relief. The nonthermal effects, such as cavitation and microstreaming, are more associated with pulsed ultrasound where energy is delivered in bursts and allows cooling between pulses. Chemical changes are not the primary goal of standard therapeutic ultrasound in this context.