What is the relationship between ultrasound intensity and tissue temperature?

What is the relationship between ultrasound intensity and tissue temperature?

• A. Higher intensity results in smaller temperature elevation.
• B. Higher intensity results in greater temperature elevation.
• C. Higher intensity has no effect on temperature.
• D. Higher intensity cools the tissue.

Answer: (B)

The key idea is that ultrasound heating depends on how much energy is deposited in the tissue. When you increase the ultrasound intensity, more acoustic energy is delivered per unit time and more of it is absorbed by the tissue and converted into heat. With the exposure conditions (time, tissue properties, and cooling factors) held constant, a higher intensity leads to a greater temperature rise. That’s why therapeutic ultrasound aims for an intensity that achieves the desired thermal effect, while balancing safety. In living tissue, other factors like frequency (affects how deeply energy is absorbed), duty cycle, and blood flow (which can carry heat away) also influence the actual temperature rise, but the overall trend remains: increasing intensity increases heating. The other statements—that higher intensity reduces heating, has no effect, or cools the tissue—don’t fit because more energy absorption from higher intensity naturally raises temperature, not lowers it.

The key idea is that ultrasound heating depends on how much energy is deposited in the tissue. When you increase the ultrasound intensity, more acoustic energy is delivered per unit time and more of it is absorbed by the tissue and converted into heat. With the exposure conditions (time, tissue properties, and cooling factors) held constant, a higher intensity leads to a greater temperature rise. That’s why therapeutic ultrasound aims for an intensity that achieves the desired thermal effect, while balancing safety.

In living tissue, other factors like frequency (affects how deeply energy is absorbed), duty cycle, and blood flow (which can carry heat away) also influence the actual temperature rise, but the overall trend remains: increasing intensity increases heating. The other statements—that higher intensity reduces heating, has no effect, or cools the tissue—don’t fit because more energy absorption from higher intensity naturally raises temperature, not lowers it.