Which transducer component is designed to shape the beam and determine focal properties?

• A. Matching layer
• B. Lens
• C. Element
• D. Backing material

Answer: (B)

Shaping the beam and setting its focal properties come from the lens. The transducer’s element emits a wave that starts with a roughly spherical front, and the lens—placed in front of or as part of the transducer—has a curved shape and specific acoustic properties that bend those waves toward a focal point. The curvature and the lens material determine where that focus lies and how tight the beam becomes at that point, so the lens directly controls focal depth and lateral resolution.

The other parts have different roles: the matching layer improves energy transfer into tissue by matching impedances, the backing material dampens the pulse to broaden bandwidth and reduce ringing, and the element itself is the source of the ultrasound signal but doesn’t define the focal geometry.