X-RAY MICROTOMOGRAPHY OF BONES AND TEETH

X-ray microtomography is a miniaturized version of computerized axial tomography with a resolution of the order of micrometres. In the biome dical field it is particularly useful in the study of hard tissue beca use of its ability to accurately measure the linear attenuation coeffi cient. From this, the mineral concentration can be computed, which is one measure of bone quality. Using microtomography it is also possible to form three-dimensional images of bone from which structural parame ters can be derived which could not be measured using conventional his tomorphometry. Various types of microtomography scanner have been used , including simple translate-rotate systems which are capable of measu ring x-ray attenuation at multiple energies simultaneously, and 'cone- beam' systems which can acquire the necessary data for three-dimension al reconstructions in a relatively short time. Both laboratory x-ray s ources and synchrotrons have been used in the study of hard tissue usi ng microtomography. Most studies of bone have been concerned primarily with either the mineral concentration in cortical bone or the structu re in cancellous bone. The mineral concentration in teeth has also bee n studied, in particular the loss of mineral in enamel during in vitro demineralization and the gain during subsequent remineralization. Alt hough there are currently relatively few centres carrying out this wor k, interest in the technique is rapidly growing and it is likely to fi nd a useful place both in research and ultimately in clinical practice .