2011.4.12 香港理工大学陈建刚博士学术报告
发布时间:2011-04-01  阅读次数:1321

报告题目:Coupling Effect of Soft Tissue on Propagation of Ultrasonic Waves in Human Bones
演讲人:陈建刚

时间:4月12日下午2:00点
地点:物理楼521室
联系人:电子工程系他得安老师

 

Coupling Effect of Soft Tissue on Propagation of Ultrasonic Waves in Human Bones

 

Jiangang CHEN

The Department of Mechanical Engineering

The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR

 

       Quantitative ultrasound (QUS) has been an attractive candidate in assessment of human bones, competing with conventional radiation-based densitometry, in its intrinsic natures being non-radiation, good portability, inexpensive implementation and ability to extract multi-parameters. To implement a QUS measurement, one can use (i) axial transmission, (ii) transverse transmission and (ii) pulse-echo, with the first one being the most promising in evaluating human long bones (e.g., tibia, radius) due to its capability to send ultrasound waves not only along bone axis but also across bone thickness. This technique is capable to reflect not only the bone material properties but also geometrical features (e.g., thickness). However, the presence of a layer soft tissue may influence the wave propagation in the bone, potentially impairing the precision and accuracy of the evaluation. Also, there is a similar concern in the nondestructive evaluation (NDE) domain where structures coupled with another medium are under inspection, e.g., water tanks containing fluid inside, offshore structures immersed in the sea water, and pipelines coated with an insulating layer, etc.

This talk introduces the presenters research work in studying the coupling effect on propagation of ultrasonic waves. Methods embrace analytical analysis, finite element simulation and experiment. Results unveiled that the coupling medium exerts a prominent effect on the propagation of ultrasonic waves in bones and engineering structures, highlighting that such a coupling effect should be compensated for in high-precision QUS and NDE applications.

 

软组织对超声波在人骨中传播的影响

 

陈建刚

香港理工大学机械工程系

 

       与传统的以放射为基础的骨密度测量法相比,定量超声在评估人骨健康状况方面越来越受到人们的关注。这源于定量超声本身的特性:无辐射,设备便携,廉价以及反映更多参数的能力。现存的定量超声技术可分为: (i) 轴向法,(ii) 横向法和 (iii) 反射法。其中,轴向法特别适合评估长骨的健康状况,比如胫骨,桡骨。这是因为轴向法发送的超声波不仅沿着骨头的长轴传播,而且分布了整个骨壁。这样接收到的超声信号不仅包含了骨的材料特性,还能反映出骨结构方面的特征,比如骨厚度。然而,人骨外面的一层软组织可能会影响超声波在人骨中的传播,进而影响到骨评估的精度和准确性。同样地,在无损检测的工程领域也存在着类似的情况,比如装满水的水箱,浸在海水中的结构,以及包裹着一层绝缘层的输油管道,等等。

本报告将介绍报告人在耦合效应对超声波传播影响方面的研究工作。方法涵盖了理论分析,有限元模拟和实验。结果表明耦合效应会对超声波在人骨以及工程结构中的传播产生明显影响。因此在一些有高精度要求的定量超声和无损检测的应用中,前面提到的耦合效应应该得到补偿。