A burning pain during ultrasound treatment indicates which issue with coupling or medium?

• A. Too much medium
• B. Insufficient medium
• C. Too much intensity
• D. Too fast movement of sound head

Answer: (B)

When ultrasound feels like a burning pain, the issue is poor acoustic coupling between the transducer and the skin. The coupling medium (gel) must fill every small gap so there are no air pockets. If there isn’t enough gel, air pockets form, and air has a very different acoustic impedance than tissue, so most of the ultrasound energy is reflected rather than transmitted into the tissue. The energy that does reach the superficial layers can then be deposited in a small area, causing rapid heating and a burning sensation. Adding more gel and ensuring the transducer stays in full contact eliminates those air gaps and normalizes energy delivery.

The other possibilities don’t fit the symptom as well. Too much medium wouldn’t inherently create a burning sensation from poor contact; it mainly changes how well contact is maintained. Too much intensity would cause heating, but it isn’t specifically about the coupling issue. Moving the head too fast changes exposure duration and area but doesn’t pinpoint inadequate coupling as the cause of the burning sensation.