Which statement about the pad (bladder) method is true?

Which statement about the pad (bladder) method is true?

• A. Pad should be filled with water or gel, and used for irregularly shaped parts
• B. Pad should be filled with air and used for flat areas
• C. Pad is never used in ultrasound
• D. Pad must be heated before use

Answer: (A)

The pad method is about achieving reliable acoustic coupling when the treated surface is irregular. Filling the pad with water or gel creates a soft, tissue-like medium that conforms to uneven contours, filling in gaps and eliminating air pockets that would reflect or scatter ultrasound. This ensures uniform contact and energy delivery to the target area. Using air would introduce a strong impedance mismatch, blocking transmission, which is why air-filled pads are not appropriate. Heating the pad isn’t required for this approach—the goal is to optimize coupling, not to warm the tissue.

The pad method is about achieving reliable acoustic coupling when the treated surface is irregular. Filling the pad with water or gel creates a soft, tissue-like medium that conforms to uneven contours, filling in gaps and eliminating air pockets that would reflect or scatter ultrasound. This ensures uniform contact and energy delivery to the target area. Using air would introduce a strong impedance mismatch, blocking transmission, which is why air-filled pads are not appropriate. Heating the pad isn’t required for this approach—the goal is to optimize coupling, not to warm the tissue.