Ultrasound causes the greatest rise in temperature in tissues with

• A. Adipose
• B. Cartilage
• C. Tendon
• D. Protein

Answer: (D)

The main concept here is how ultrasound energy is absorbed by different tissues. Heating from ultrasound depends on how much energy the tissue absorbs, which is tied to its attenuation properties. Proteins, especially collagen, absorb ultrasound energy more readily than lipids or mineral components. When energy is absorbed, it is transformed into heat, so protein-rich tissues convert more acoustic energy into thermal energy and therefore experience a greater rise in temperature. Adipose tissue has relatively little protein, so it absorbs less energy and heats less. So, among the options, tissue with high protein content will heat the most under the same ultrasound exposure.