Yokosawa K, Shinomura R, Sano S, Ito Y, Ishikawa S, Sato Y
Central Research Laboratory, Hitachi, Ltd., Tokyo, Japan.
Ultrason Imaging. 1996 Oct;18(4):231-9. doi: 10.1177/016173469601800401.
Ultrasound transducers with center frequency above 100 MHz are expected to be used for future diagnostic tissue characterization because of their high lateral resolution. We have fabricated a 120-MHz transducer that consists of a ZnO piezoelectric film on a sapphire substrate that has a concave acoustic lens. The lateral resolution was calculated as 13 microns. The insertion loss of the transducer, defined as the difference between the received voltage and the transmitted one, was -45 dB. The 6-dB handwidth of the received signal was approximately 40 MHz. The transducer was mounted in a rod-shaped probe to ensure contact with in vivo tissue, because of the low penetration of ultrasound in the high frequency region. While the probe is rotated and moved along its axis mechanically, the transducer receives backscattered ultrasound from the surrounding tissue on a cylindrical plane that is kept a constant distance from the probe surface. The feasibility of this high-frequency tissue imaging probe has been demonstrated by obtaining preliminary images of an in vitro bovine kidney.
由于具有高横向分辨率，预计中心频率高于100MHz的超声换能器将用于未来的诊断组织表征。我们制造了一个120MHz的换能器，它由蓝宝石衬底上的ZnO压电薄膜组成，该衬底具有凹面声透镜。横向分辨率计算为13微米。换能器的插入损耗定义为接收电压与发射电压之差，为-45dB。接收信号的6dB带宽约为40MHz。由于超声在高频区域的穿透性低，该换能器安装在棒状探头中以确保与体内组织接触。当探头沿其轴机械旋转和移动时，换能器在与探头表面保持恒定距离的圆柱平面上接收来自周围组织的反向散射超声。通过获取体外牛肾的初步图像，证明了这种高频组织成像探头的可行性。
