Continuous ultrasound is defined as:

Continuous ultrasound is defined as:

• A. A mode in which the sound intensity remains constant and energy is produced 100% of the time.
• B. A mode that delivers energy in pulses with rest periods.
• C. A mode that only operates at low frequencies.
• D. A mode used only for deep heating with no acoustic energy.

Answer: (A)

This question tests how ultrasound energy is delivered—continuous versus pulsed. In continuous mode the transducer emits energy without interruption, so the intensity stays constant and energy is delivered 100% of the time. This uninterrupted delivery is what defines continuous ultrasound and is why it’s used when sustained tissue heating is desired. The other descriptions describe different ideas. Delivering energy in pulses with rest periods is pulsed ultrasound, not continuous. Operating only at low frequencies isn’t what defines continuous mode, since continuous delivery can occur at the standard therapeutic frequencies (often around 1 or 3 MHz). Saying it’s used for deep heating with no acoustic energy contradicts physics, because ultrasound inherently involves acoustic energy.

This question tests how ultrasound energy is delivered—continuous versus pulsed. In continuous mode the transducer emits energy without interruption, so the intensity stays constant and energy is delivered 100% of the time. This uninterrupted delivery is what defines continuous ultrasound and is why it’s used when sustained tissue heating is desired.

The other descriptions describe different ideas. Delivering energy in pulses with rest periods is pulsed ultrasound, not continuous. Operating only at low frequencies isn’t what defines continuous mode, since continuous delivery can occur at the standard therapeutic frequencies (often around 1 or 3 MHz). Saying it’s used for deep heating with no acoustic energy contradicts physics, because ultrasound inherently involves acoustic energy.