Compared with pulsed ultrasound at the same intensity, continuous wave ultrasound has what effect on tissue heating?

Compared with pulsed ultrasound at the same intensity, continuous wave ultrasound has what effect on tissue heating?

• A. Increases Tissue Heating
• B. Decreases Tissue Heating
• C. No Effect
• D. Unpredictable Effect

Answer: (A)

Heating from ultrasound depends on how much energy is delivered to tissue over time. Continuous wave ultrasound emits energy nonstop, so the tissue continually absorbs energy and has little opportunity to cool between moments of exposure. Pulsed ultrasound delivers energy in bursts with off times, allowing heat to dissipate between pulses. Even if the peak intensity is the same, the average energy deposited over time is higher with continuous wave, leading to greater temperature rise. So continuous wave ultrasound increases tissue heating compared with pulsed ultrasound at the same intensity.

Heating from ultrasound depends on how much energy is delivered to tissue over time. Continuous wave ultrasound emits energy nonstop, so the tissue continually absorbs energy and has little opportunity to cool between moments of exposure. Pulsed ultrasound delivers energy in bursts with off times, allowing heat to dissipate between pulses. Even if the peak intensity is the same, the average energy deposited over time is higher with continuous wave, leading to greater temperature rise. So continuous wave ultrasound increases tissue heating compared with pulsed ultrasound at the same intensity.