Focused intravascular ultrasonic probe using dimpled transducer elements

High-frequency focused intravascular ultrasonic probes were fabricated in this study using dimple technique based on PMN-PT single crystal and lead-free KNN-KBT-Mn ceramic. The center frequency, bandwidth, and insertion loss of the PMN-PT transducer were 34 MHz, 75%, and 22.9 dB, respectively. For the lead-free probe, the center frequency, bandwidth, and insertion loss were found to be 40 MHz, 72%, and 28.8 dB, respectively. The ultrasonic images of wire phantom and vessels with good resolution were obtained to evaluate the transducer performance. The -6 dB axial and lateral resolutions of the PMN-PT probe were determined to be 58 mu m and 131 mu m, respectively. For the lead-free probe, the axial and lateral resolutions were found to be 44 mu m and 125 mu m, respectively. These results suggest that the mechanical dimpling technique has good potential in preparing focused transducers for intravascular ultrasound applications. (C) 2014 Elsevier B.V. All rights reserved.