The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	The design and testing of a personal computer controlled scanning acoustic microscope for orthopaedic surgical applications
Author:	Berndt, Hubert Heinrich
View Online:	njit-etd1991-079 ([viii], [124] pages ~ 9.6 MB pdf)
Department:	Department of Electrical Engineering
Degree:	Master of Science
Program:	Electrical Engineering
Document Type:	Thesis
Advisory Committee:	Zimmerman, Mark (Committee chair) Parsons, J. Russell (Committee member) Carpinelli, John D. (Committee member) Reisman, Stanley S. (Committee member)
Date:	1991-05
Keywords:	Acoustic microscopes -- Design and construction Femur -- Mechanical properties Orthopedic surgery Image processing
Availability:	Unrestricted
Abstract:	This thesis describes scanning acoustic microscopy and ultrasonic image processing to characterize and evaluate materials of known properties, as well as novel materials. This work describes the assembly and testing of a PC based device for nondestructive evaluation of bone materials for usage in orthopaedics research. It includes the identification of some hardware problems and their solution, and it also describes different image processing techniques that have been developed and applied in this work. In a growing number of disciplines it has been discovered that an acoustic microscope can provide new information, especially about the elastic properties of specimens and how acoustic waves interact with them. This work examines a PC based apparatus for scanning acoustic microscopy and the testing of this device by investigating different materials. In this thesis ultrasound has been used to evaluate the elastic or stiffness properties of human bone specimens, in particular those from femurs. Dependent on the location within the bone, the data obtained is an approximate value proportional to the local stiffness of bone on the surface of the investigated specimen. Such data can be used for studies of mechanical remodelling of the entire bone. In order to evaluate the physical/acoustic properties and to obtain detailed representations, the data from the scanned object is subjected to conversions and further ultrasonic image processing. Using different image processing techniques, it is also possible to compare the extracted data to that from other specimens that differ in size and shape. Further information about the physical properties of a material can be obtained by analyzing either reflected or transmitted ultrasound. Scanning acoustic microscopy (SAM) is a reflection technique where the amplitude of the reflected sound wave is measured. Using the transmission technique, it is possible to determine the velocity of an acoustic wave through the investigated material. In bone and only in bone materials, there exists a strict connection between the transmitted velocity, acoustic impedance or reflected wave amplitude and modulus of elasticity (Young's modulus).