Using ultrasound at 1.5 W/cm2 for 10 minutes can increase tissue temperature by approximately how many degrees Fahrenheit up to 2.5 cm deep?

Using ultrasound at 1.5 W/cm2 for 10 minutes can increase tissue temperature by approximately how many degrees Fahrenheit up to 2.5 cm deep?

• A. 5° to 6°F
• B. 7° to 8°F
• C. 9° to 10°F
• D. 11° to 12°F

Answer: (B)

Therapeutic ultrasound raises tissue temperature by converting acoustic energy to heat, and the amount of heating depends on how long you run it, how strong the intensity is, and how deep the energy penetrates. With a continuous application at 1.5 W/cm2 for 10 minutes, tissues down to about 2.5 cm can warm enough to produce roughly a 7–8°F rise (about 4°C). This depth aligns with the deeper heating you get from a 1 MHz setting, where energy still reaches several centimeters but attenuates with depth, so the surface warms more than the deeper tissues. That range (7–8°F) is consistent with these parameters, giving meaningful warming without risking overheating. The smaller increase (around 5–6°F) would suggest less duration or lower effective absorption, while a much higher rise (9–12°F) would typically require higher intensity, longer duration, or different frequency, which aren’t indicated by these settings.

Therapeutic ultrasound raises tissue temperature by converting acoustic energy to heat, and the amount of heating depends on how long you run it, how strong the intensity is, and how deep the energy penetrates. With a continuous application at 1.5 W/cm2 for 10 minutes, tissues down to about 2.5 cm can warm enough to produce roughly a 7–8°F rise (about 4°C). This depth aligns with the deeper heating you get from a 1 MHz setting, where energy still reaches several centimeters but attenuates with depth, so the surface warms more than the deeper tissues.

That range (7–8°F) is consistent with these parameters, giving meaningful warming without risking overheating. The smaller increase (around 5–6°F) would suggest less duration or lower effective absorption, while a much higher rise (9–12°F) would typically require higher intensity, longer duration, or different frequency, which aren’t indicated by these settings.