ULTRASONIC MEASUREMENT OF THICKNESSES OF BONE AND BONE-MARROW WITHIN FEMUR INSERTED WITH A METAL STEM

The thicknesses of the bone and the bone marrow region within a pig fe mur inserted with a metal stem of the total hip replacement system are investigated nondestructively by means of an ultrasonic pulse echo te chnique. First, the wave velocities through bone and bone marrow are d etermined using an ultrasonic wave which enables observation of the ti me intervals between the first and second echoes in these specimens. N ext, the ultrasonic wave is emitted toward the femur with the metal st em, which was immersed in a water tank, and the distances from a norma l probe to the boundary surfaces of the bone and the metal stem are me asured. Subsequently, the exact thicknesses of the bone and the bone m arrow region are measured using vernier calipers. The results of the u ltrasonic wave and vernier caliper measurements are graphically presen ted and compared. The ultrasonic method is found to be applicable for the proposed purpose.