报告题目：Ultrasonic Imaging of Cortical Bones
报 告 人：Prof. Lawrence H. Le（University of Alberta）
Osteoporosis is a systemic disorder of the skeleton affecting over 200 million women worldwide. The bone disease is characterized by low bone mass, deteriorated microstructures, and cortical thinning of bone tissues. The loss of trabeculae and cortical bones through the process of trabecularization disrupts the bone strength and consequently leads to increase of bone fragility and fracture risk. The rate of bone loss is greater in women than men with women experiencing accelerated bone loss following menopause. Cortical thickness and elasticity are important determinants of bone strength. The cortex is a strong waveguide because it has much larger acoustic impedance than those of the surrounding soft tissues. Quantitative guided wave ultrasonography is particularly attractive because of the sensitivity of guided waves to the geometry, micro-architecture, and material properties of the cortex. However, the problem to extract bone properties of the cortex using guided waves is challenging because the long bone is inhomogeneous, absorptive, and transversely isotropic with irregular thickness and surface. In this presentation, I will present some of the methodologies that our group has developed to solve the problem.
Lawrence H. Le received his PhD in earth physics from the University of Alberta, Edmonton, Canada. He held a NSERC (Natural Sciences and Engineering Research Council of Canada) industrial postdoctoral fellowship in Schlumberger-Doll Research Lab, Ridgefield, Connecticut. He started his medical physics residency training in the Department of Radiology and Diagnostic Imaging (DRDI), University of Alberta in 1994. Subsequently, he completed a MBA degree in Finance and Technology commercialization at the University of Alberta. He joined the DRDI at the University of Alberta as an academic staff and Capital Health as a clinical medical physicist in 2000. He is currently a professor in Medical Physics leading the graduate program in DRDI and the Edmonton Authorized Radiation Protection Agency within Alberta Health Services. He is also a senior Visiting Scholar of the State Key Laboratory of ASIC and System, Fudan University. He directs the Ultrasonic Bone Tissue Characterization and Imaging group. He guides his students to use vigorous geophysical techniques to image and study bone tissues. His research interests are in imaging, signal and image processing, simulation, and inversion. Lawrence is a member of AAPM (The American Association of Physicists in Medicine) and COMP (The Canadian Organization of Medical Physicists).