Current status and future trends in ultrasonic transducers for medical imaging applications

Ultrasonic medical imaging provides a low cost and non-invasive tool to look inside the human body. The ultrasound transducer composed of various components including a piezoelectric material, and matching and backing layers, provides a link between the human body being imaged and the system electronics. Proper choice of the individual material components and the overall design of the transducer play an important role in the determining the final image quality. The basic design principles for fabrication of ultrasound transducers and their effect on the device performance are presented. Some recent advances in ultrasound, including 2-D arrays, 3-D image reconstruction, Doppler color flow imaging, and harmonic and contrast agent imaging have also been briefly described. Finally, the discovery of high coupling constant single crystal piezoelectric materials and their impact on the transducer performance are discussed.