Three-dimensional distribution of mineral in bone at a resolution of 15 micron determined by x-ray microtomography.

The application of x-ray microtomography (computerized axial tomography) to the histomorphometry of bone at a resolution of approximately 15 micron is described. Serial sections (obtained without physically cutting the sample) separated by 25 micron were made from an 0.8 mm square rod of human femoral bone. These showed several haversian canals and changes in mineralization within individual sections. The results obtained are quantitative in terms of the x-ray linear absorption coefficient, which is closely related to the degree of mineralization. Thus x-ray microtomography has the potential for the nondestructive determination of the fractional bone volume, with the ability to select the degree of mineralization of the bone used to determine the fraction.