This thesis presents a new technique in which x-ray diffraction has been adapted to the clinical environment in order to quantify the osteoporotic state of bone tissue. The constraints of a clinical system demand diffraction apparatus with short wavelengths, a low photon flux and a short measurement time. Of the two forms of measurement for recording diffraction patterns the fixed detector, energy dispersive technique was found to be better suited to clinical work than the scanning detector, angular distributive approach. Various procedures to remove unwanted effects in the data are presented, along with a Monte Carlo simulation designed to investigate the effect of variation in patient thickness and bone volume on the relative proportion of elastic scatter. Diffraction peaks due to bone and marrow tissue were identified in the scatter pattern of trabecular bone. The relative intensities of the two peaks within the pattern are shown to quantify the relative proportions of the two components, and so the bone-to-marrow peak ratio was proposed as a parameter to assess the osteoporotic state of trabecular tissue. Results from anthropomorphic phantoms demonstrate a significant correlation between this method and the established bone density measurement techniques of quantitative computerised tomography and Compton scatter densitometry. The inherent uniqueness of the diffraction pattern was also applied to tissue characterisation, in particular to the identification of gallstones. Gallstones can be classified into three main categories according to their crystalline constituents, each type requiring different patient treatment. A clear distinction between the three stone types is demonstrated with this method. The principal advantages of this technique are its ability to focus on a small volume within the object, such as the trabecular region within bone, the capability of in-vivo measurement and the ability to isolate the responses from the bone and marrow
