Ultrasound involves the use of a small _________________

• A. Transducer (probe/wand)
• B. Antenna
• C. Gel applicator
• D. Sensor

Answer: (B)

Ultrasound imaging relies on a transducer, the small handheld device that both emits ultrasound waves and receives their echoes. Inside the transducer are piezoelectric crystals that convert electrical energy into mechanical vibrations to produce sound, and then convert the returning echoes back into electrical signals to create the image. The gel is used to improve contact between the skin and the transducer, allowing efficient transmission by eliminating air gaps. An antenna relates to electromagnetic waves, not sound waves, so it isn’t used in ultrasound. A gel applicator just applies the gel, and a sensor is a generic term that doesn’t specify the imaging component responsible for producing and detecting ultrasound.