Non-thermal intensity is less than which value?

Non-thermal intensity is less than which value?

• A. Less than 0.5 W/cm2 average intensity
• B. 0.5 W/cm2 average intensity
• C. 1.0 W/cm2
• D. 2.0 W/cm2

Answer: (A)

Non-thermal effects from ultrasound come from mechanical energy (like cavitation and microstreaming) rather than tissue heating. To keep heating minimal and emphasize those mechanical effects, the average intensity must be kept very low. That’s why non-thermal intensity is defined as being less than 0.5 W/cm2 on average. In practice, clinicians use pulsed delivery and a low duty cycle to maintain this below-0.5 threshold so heating doesn’t occur. If the average intensity reaches 0.5 W/cm2 or higher, heating becomes noticeable, shifting the effects toward thermal rather than non-thermal.

Non-thermal effects from ultrasound come from mechanical energy (like cavitation and microstreaming) rather than tissue heating. To keep heating minimal and emphasize those mechanical effects, the average intensity must be kept very low. That’s why non-thermal intensity is defined as being less than 0.5 W/cm2 on average. In practice, clinicians use pulsed delivery and a low duty cycle to maintain this below-0.5 threshold so heating doesn’t occur. If the average intensity reaches 0.5 W/cm2 or higher, heating becomes noticeable, shifting the effects toward thermal rather than non-thermal.