A frequency of what is used for heating superficial with depth less than 2 cm?

A frequency of what is used for heating superficial with depth less than 2 cm?

• A. 1.0 MHz
• B. 3.0 MHz
• C. 2.0 MHz
• D. 5.0 MHz

Answer: (B)

When using therapeutic ultrasound, the frequency determines how deep the energy is absorbed. Higher frequency heats tissues closer to the surface, while lower frequency penetrates deeper. For targets at a depth up to about 2 cm, a frequency around 3 MHz is ideal because it concentrates heating in the superficial to near-superficial layers without reaching much deeper tissues. A lower frequency like 1.0 MHz would reach deeper structures than intended, and a higher frequency like 5.0 MHz would heat only the very surface, possibly not reaching the full 2 cm depth. So 3.0 MHz provides the proper balance to heat tissues within that shallow depth.

When using therapeutic ultrasound, the frequency determines how deep the energy is absorbed. Higher frequency heats tissues closer to the surface, while lower frequency penetrates deeper. For targets at a depth up to about 2 cm, a frequency around 3 MHz is ideal because it concentrates heating in the superficial to near-superficial layers without reaching much deeper tissues. A lower frequency like 1.0 MHz would reach deeper structures than intended, and a higher frequency like 5.0 MHz would heat only the very surface, possibly not reaching the full 2 cm depth. So 3.0 MHz provides the proper balance to heat tissues within that shallow depth.