What does a 100% duty cycle indicate in continuous ultrasound?

What does a 100% duty cycle indicate in continuous ultrasound?

• A. Sound waves are present, thermal effects
• B. No waves emitted
• C. Pulsed emission
• D. Nonthermal only

Answer: (A)

Duty cycle is the fraction of time the ultrasound transducer is emitting during each cycle. A 100% duty cycle means the device is on the entire time, so emission is continuous. Because energy is delivered without breaks, tissue heating occurs, leading to thermal effects. In contrast, pulsed emission (duty cycle less than 100%) reduces heating and emphasizes nonthermal, mechanical effects. So the correct interpretation is that sound waves are present and produce thermal effects.

Duty cycle is the fraction of time the ultrasound transducer is emitting during each cycle. A 100% duty cycle means the device is on the entire time, so emission is continuous. Because energy is delivered without breaks, tissue heating occurs, leading to thermal effects. In contrast, pulsed emission (duty cycle less than 100%) reduces heating and emphasizes nonthermal, mechanical effects. So the correct interpretation is that sound waves are present and produce thermal effects.