【電機系書報討論演講訊息】
書報討論網頁：http://lms.nthu.edu.tw/course/19186
演講公告網址：/p/403-1175-2629-1.php
題 目：新世代醫用超音波影像發展
New generation ultrasound imaging for medical applications
講 員：黃執中 教授 (成功大學)
時 間：2014年9月26日(星期五) 下午2時20分
地 點：學習資源中心旺宏館245教室(即圖書館2樓)
Abstract
It is well known that the mechanical properties of soft tissues, such as elasticity, viscosity and mechanical impedance, change depending on the conditions of tissues, for instance disease and age, hence there mechanical properties may give useful information in medical diagnosis. Several direct force applied methods have been proposed to measure the mechanical properties of tissue quantitatively, such as sonoelastographic image. Besides, uses of acoustic radiation force to remotely palpate tissue have been developed by various researchers as an alternative to conventional ultrasound elasticity image. However, most operational frequencies of acoustic radiation force imaging are smaller than 10 MHz. The resolution of 10 MHz is not good enough for imaging the microstructure in some eye tissue. Consequently, we attempt to develop the high frequency acoustic radiation force technology for providing high resolution elasticity image in ophthalmology applications. The main purpose of this project is to develop the high frequency acoustic radiation force technology for characterizing the mechanical properties of soft tissue, such as thrombosis and cornea. In thrombosis study, the theoretical analysis and experimental verification of using acoustic radiation force to measure the viscoelastic properties of clot were proposed. The blood clots were created artificially with different coagulating factors, such as hematocrit, fibrinogen, and thrombin. Both of viscous and elastic parameters of blood clot were measured for the further development of acoustic radiation force technology in thrombosis applications. In cornea study, a 20-50 MHz high frequency acoustic radiation force impulse (ARFI) image system were built for mapping the hardness of cornea. A two elements confocal ultrasonic transducer was designed for this objective. The outer 10 MHz element was used to push the fibers in cornea and the inner 50 MHz element was used to detect the displacement of cornea. The experiments were carried out using artificial porcine cornea and a new algorithm for high frequency ARFI imaging was established. Furthermore, the feasibility of using high frequency ARFI image for identifying the mechanical properties of cornea and retinal vein thrombosis were be performed. We applied our high frequency ARFI image system into intravascular ultrasound (IVUS). In the first stage, a concept of combining the high frequency AFRI and shear wave technology on IVUS for assessing the mechanical properties of thrombus and vessel was proposed in present study.
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