Interfacing very high frequency transducers to digital-acquisition scanning systems

ABSTRACTPolymer transducers with high center frequencies offer several potential advantages for ultrasonic imaging and tissue characterization of superficial tissue segments. The large bandwidths of these transducers permit resolution of small tissue structures and also provide detailed spectral data for characterizing stochastic tissueelements. We have integrated these transducers with digital systems and conducted initial examinations of theeye, skin, and in-vitro tissue specimens. Computed images have demonstrated superior resolution, and usefulsignal-to-noise ratios have been obtained for spectral bandwidths exceeding 35 MHz. Further investigations arerequired to develop compensating processing techniques for acoustic attenuation and frequency-dependent beamcharacteristics, which can be significant factors over these large bandwidths. 1. INTRODUCTION Medical ultrasonography1 has become a widely used diagnostic method in a broad spectrum of specialties including radiology, cardiology, obstetrics, gynecology, and ophthalmology. In spite of their demonstrated