A frequency of what depth is used for heating deeper tissues (up to 5 cm) in ultrasound therapy?

A frequency of what depth is used for heating deeper tissues (up to 5 cm) in ultrasound therapy?

• A. 3.0 MHz
• B. 0.5 MHz
• C. 1.0 MHz
• D. 2.0 MHz

Answer: (C)

The main idea here is how ultrasound frequency affects how deep the energy absorbs and heats tissue. Lower frequencies penetrate deeper, while higher frequencies heat more superficial tissues. For targeting tissues about 5 cm beneath the surface, 1.0 MHz is the best choice because it provides enough penetration to reach that depth while still delivering meaningful heating. Higher frequencies like 2.0 and 3.0 MHz mostly heat the near-surface layers (roughly 1–2 cm), so they wouldn’t reach a 5 cm depth effectively. The lowest frequency, 0.5 MHz, can reach deeper than 5 cm, but the heating is less efficient and less predictable for a defined 5 cm target. So 1.0 MHz offers the optimal balance for heating tissues around 5 cm deep.

The main idea here is how ultrasound frequency affects how deep the energy absorbs and heats tissue. Lower frequencies penetrate deeper, while higher frequencies heat more superficial tissues. For targeting tissues about 5 cm beneath the surface, 1.0 MHz is the best choice because it provides enough penetration to reach that depth while still delivering meaningful heating. Higher frequencies like 2.0 and 3.0 MHz mostly heat the near-surface layers (roughly 1–2 cm), so they wouldn’t reach a 5 cm depth effectively. The lowest frequency, 0.5 MHz, can reach deeper than 5 cm, but the heating is less efficient and less predictable for a defined 5 cm target. So 1.0 MHz offers the optimal balance for heating tissues around 5 cm deep.