Ultrasonic Measurement of Bone Density and Young's Modulus (Examination of Accuracy of the Measurement)

This study was performed as a part of the research on the ultrasonic measurement in vivo of bone porosity, density, Young modulus and hardness. It was clarified that the bone porosity estimated by Biot's theory agrees well with the actual porosity within an accuracy of 5%. In the estimation the structure factor involved in the Biot's theory was determined as a value of 2. In this evaluation, an use of the propagation velocity of the fast wave is more advantageous to estimate the bone porosity than using the one of the slow wave. The estimated bone density by Biot's theory yields only ±5% differences from the measured value by the Archimedes method. Therefore, bone density can be estimated precisely by using the proposed ultrasonic wave method.