A 30-MHz piezo-composite ultrasound array for medical imaging applications

TLDR

Ultrasound imaging above 20 MHz can provide improved resolution for clinical applications that require limited penetration depth. High‑frequency arrays enabling real‑time imaging are needed for these applications, yet such arrays are not yet commercially available. The authors fabricated a 30‑MHz piezo‑composite array incorporating acoustic matching, elevation focusing, electrical matching, and an air‑filled kerf, and used synthetic aperture reconstruction to acquire images of a phantom and an ex vivo human eye. The resulting array exhibited high thickness coupling, low mechanical loss, moderate electrical loss, ~60 % bandwidth, 15‑dB insertion loss, crosstalk < −30 dB, and delivered ~100 μm lateral and axial resolution in the acquired images.

Abstract

Ultrasound imaging at frequencies above 20 MHz is capable of achieving improved resolution in clinical applications requiring limited penetration depth. High frequency arrays that allow real-time imaging are desired for these applications but are not yet currently available. In this work, a method for fabricating fine-scale 2-2 composites suitable for 30-MHz linear array transducers was successfully demonstrated. High thickness coupling, low mechanical loss, and moderate electrical loss were achieved. This piezo-composite was incorporated into a 30-MHz array that included acoustic matching, an elevation focusing lens, electrical matching, and an air-filled kerf between elements. Bandwidths near 60%, 15-dB insertion loss, and crosstalk less than -30 dB were measured. Images of both a phantom and an ex vivo human eye were acquired using a synthetic aperture reconstruction method, resulting in measured lateral and axial resolutions of approximately 100 /spl mu/m.