During water-immersion ultrasound for ankle rehab, air bubbles accumulate on the skin under the transducer and on the soundhead. What should the therapist do?

• A. Wipe off air bubbles on the skin periodically
• B. Wipe off air bubbles on the face of the soundhead periodically
• C. Wipe off air bubbles on the skin and face of the soundhead periodically
• D. Avoid wiping off any of the air bubbles

Answer: (C)

Air pockets between the transducer, the water, and the skin disrupt ultrasound transmission. To keep energy delivered efficiently and heat produced evenly, you must maintain good acoustic coupling by wiping away bubbles from both the skin under the transducer and the face of the soundhead periodically. This prevents impedance mismatches that reflect or scatter the sound waves and ensures the treatment remains effective. If bubbles recur, re-wet the area and wipe again to maintain continuous contact.