Dual frequency transducer design for suppression of multiple scattering

Reverberation noise reduces the contrast resolution in ultrasound images. In some cases the signal from the anatomy can be completely masked out, making diagnosis challenging. SURF (Second-order Ultrasound Field) imaging is a dual band imaging technique that has shown the capability to suppress reverberation noise and enhance the anatomical signal, providing a higher contrast resolution. SURF transducers radiate pulse complexes comprised of two widely separated frequencies through a partially common radiation surface. In order to achieve optimal noise suppression, careful design of the acoustic stack and radiation apertures is needed. This paper presents the optimisation criteria for SURF probes, and describes design solutions using a 9/0.5 MHz linear array for carotid imaging as an example. Simulated transfer functions are compared to those of a manufactured probe.