Application of acoustic phase conjugate waves to the distortion-free ultrasonic imaging and self-targeting system for medical purposes

声相位共轭波在医用无失真超声成像及自瞄准系统中的应用

基本信息

批准号：
10555021
负责人：
TAKAGI Kenshiro
金额：
$ 8.26万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

The phenomenon of ultrasonic phase conjugation has attracted a great interest for its potential applications, for example, to non-destructive inspection and medical ultrasonics. The time reversal property of the phase conjugate waves has the important ability of the automatic correction of the wave front disturvance. Image distortion in the NDE (Non-Destructive Evaluation) apparatus or diagnosis system will be corrected by the phase conjugate waves. The time reversal waves will also been applied to the self-focussing system for the medical treatment against cancer cells or bladder stones. In our previous works, we had developed a new ultrasonic phase conjugator of PZT ceramics ; succeeded in the visualization of the time reversal propagation of the phase conjugate waves ; and shown a possible application to the ultrasonic NDI or medical apparatus. In the present research, we aimed to a) construct a ultrasonic imaging system with the PZT phase conjugator and establish a distortion-free-imaging ; and b) develop a self-focussing system with the time reversal waves.In these two years, we attained the following results. 1) We made a scanning imaging system that was equipped with the PZT ceramic phase conjugator operating at 15 MHz, compared the normal image with the phase conjugate image, and found that the image distortion obvious in the former was successfully corrected in the latter. 2) We increased the reflectivity of the PZT phase conjugator to 100% in intensity. 3) In order to develop a self-focussing system of practical use, a phase conjugator with efficiency exceeding 100% would be inevitable. For this purpose, we tested the new piezoelectric single crystal PZNT (relaxer dielectric crystal) add measured the third-order constants of piezoelectricity and dielecricity. We found the very high non-linearlity and showed that it could be the most expecting material for the phase conjugate amplifier.

超声相结合的现象对其潜在应用引起了极大的兴趣，例如，对非破坏性检查和医学超声检查引起了极大的兴趣。相结合波的时间逆转特性具有自动校正波前干扰的重要能力。 NDE（非破坏性评估）设备或诊断系统中的图像失真将通过相结合波纠正。时间逆向波还将应用于针对癌细胞或膀胱结石的医疗治疗的自我关注系统。在以前的作品中，我们开发了一种新的超声波相结合器PZT陶瓷。在相结合波的时间逆转传播的可视化中取得了成功。并显示了可能应用于超声波NDI或医疗设备。在本研究中，我们旨在a）用PZT相结合器构建超声成像系统，并建立无失真的成像； b）开发一个随时间逆转的自我关注系统。在这两年中，我们获得了以下结果。 1）我们制作了一个扫描成像系统，该扫描成像系统配备了15 MHz的PZT陶瓷相结合器，将正常图像与相结合图像进行了比较，并发现前者的图像变形很明显。 2）我们将PZT相结合器的反射率提高到强度100％。 3）为了开发一种自我关注的实际使用系统，效率超过100％的相结合器是不可避免的。为此，我们测试了新的压电单晶体PZNT（松弛剂介电晶体）添加了测量的压电性和二元性的三阶常数。我们发现了非常高的非线性拉链，并表明它可能是相结合放大器最期待的材料。