MRI/RUI: Acquisition of Instrumentation to Modernize and Enhance an Ultrasonic Scanning System

Rhodes College, Memphis TN

Investigators

Abstract

A grant has been awarded to Rhodes College under the direction of Dr. Brent Hoffmeister to modernize and enhance an ultrasonic scanning system currently in their possession. The system operates by mechanically scanning an ultrasonic transducer over a specimen to rapidly perform ultrasonic measurements at multiple sites on the specimen. The mechanical components of the present system are in excellent condition, but the electronics (including the 486 platform computer used to control the system) are obsolete. The grant will be used to modernize the scanning system and to expand its acoustic frequency range from approximately 1-7.5 MHz to 0.3-150 MHz. Major items in the budget include a new computer to control the system, a new computer for data analysis, a new A/D board for waveform digitization, new motion control electronics, a wider selection of ultrasonic transducers, a new ultrasonic pulser-receiver for use with high frequency (>35 MHz) ultrasonic transducers, and a digitizing oscilloscope capable of analyzing high frequency ultrasonic signals. The scanning system will be used to support undergraduate research. It is well suited for this purpose because the basic principles of its operation are accessible to undergraduate students. For example, students learn the basic principles of acoustic wave propagation in their first semester of physics. The system builds upon these fundamental concepts to teach students about wave propagation in more complicated, anisotropic and inhomogeneous materials. Immediate research plans for the system will involve studies of two such materials: cancellous bone and articular cartilage. Ultrasonic measurements will be performed to determine how the content and organization of mineral, collagen and other tissue constituents affect the scattering of ultrasonic waves propagated into the tissue. Students working on these projects will be exposed to a highly interdisciplinary area of research involving physics, biology and engineering. The improved ultrasonic scanning system will be a basic research instrument similar to an NMR spectrometer or electron microscope in the flexibility of its possible research applications. Specific measurements that can be performed include the speed of sound through materials (sensitive to the elastic properties of the material), attenuation (sensitive to the viscous properties of the material) and scattering (sensitive to the inhomogeneous properties of the material). It represents a powerful tool for studying the physical properties of a wide variety of materials, and will provide researchers in the region surrounding Rhodes College with an important research instrument that otherwise would be unavailable. The system will impact students from several groups including science majors at Rhodes College and surrounding institutions, students participating in summer undergraduate research programs at these institutions, and students enrolled in a unique B.S.-M.S. program in biomedical engineering involving Rhodes College, the University of Memphis and the University of Tennessee.