PULSE-ECHO IMAGING USING A NONDIFFRACTING BEAM TRANSDUCER
PULSE-ECHO IMAGING USING A NONDIFFRACTING BEAM TRANSDUCER
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DOI：
10.1016/0301-5629(91)90048-2
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发表时间：
1991-01-01
影响因子：
2.9
通讯作者：
GREENLEAF, JF
中科院分区：
文献类型：
--
作者：
LU, JY;GREENLEAF, JF
传统的超声波换能器产生的波束在行进时会产生反作用。 这种现象导致在B模式下产生的图像在换能器的远场中退化。 聚焦换能器用于改善图像质量。 不幸的是，聚焦传感器的景深较短。 虽然聚焦在若干深度处的多个脉冲发射用于增加有效景深，但是成像帧速率显著降低，导致诸如心脏的移动对象的模糊图像。 我们提出了一个家庭的换能器，产生大景深的无衍射光束。 因此，可以在不牺牲成像帧速率的情况下获得整个成像区域的均匀高分辨率。 此外，这些光束的无衍射特性使得在组织定征中对光束衍射的校正可以忽略不计。 本文报道了计算机模拟的结果，以及在体外和体内的脉冲回波成像实验与无衍射换能器。 图像进行了比较，通过传统的聚焦高斯阴影束换能器和商业ACUSON 128 B-扫描仪获得的。 与同口径的传统换能器相比，新换能器具有更长的景深和更高的旁瓣。 使用新的换能器发射和动态聚焦换能器接收可以减少旁瓣。
Conventional ultrasonic transducers generate beams that diffract as they travel. This phenomenon causes images produced in B-mode to be degraded in the far-field of the transducers. Focused transducers are used to improve image quality. Unfortunately, focused transducers have short depth of field. Although multiple pulse transmissions focused at several depths are used to increase the effective depth of field, imaging frame rate is reduced dramatically leading to blurred images of moving objects such as the heart. We present a family of transducers that produce nondiffracting beams of large depth of field. Therefore, uniformly high resolution throughout the imaging area can be obtained without sacrificing the imaging frame rate. In addition, the nondiffracting property of these beams makes the correction for beam diffraction negligible in tissue characterization. This paper reports the results of computer simulations as well as in vitro and in vivo pulse-echo imaging experiments with a nondiffracting transducer. Images are compared to those obtained by conventional focused Gaussian shaded beam transducers and a commercial ACUSON 128 B-scanner. The new transducer has much longer depth of field with higher sidelobes than conventional transducers of the same aperture. Sidelobes can be reduced using the new transducer to transmit and the dynamically focused transducer to receive.