Determination of the elasticity coefficient for a single trabecula of a cancellous bone: scanning acoustic microscopy approach.

Scanning acoustic microscope techniques enable determination of mechanical properties of small samples. These techniques can be applied to a single trabecula of the cancellous bone. This paper describes nondestructive methods for assessing the bone tissue elasticity for samples accessible from one side only. Two methods are applied in the same area of a trabecula. The first one allows determination of the tissue impedance, based on the correlation between the grey levels of the scanning acoustic microscope images and of the reference material of a known impedance. The second newly-developed technique enables measurement of the velocity of surface waves with a spatial resolution less than 100 mum, using theoretical and experimental analysis of the position of the first interference of the V(z) curve. These two experimentally-derived parameters were used to calculate the density and elasticity coefficient for trabecular bone samples of patients who suffered from metabolic bone diseases, such as osteoporosis, osteomalacia and osteoidosis. Medical descriptions of these diseases explain the differences in mechanical properties of trabecular bone tissue found experimentally.