The newest generation of micro computed tomography (microCT) scanners, incorporating improved beam- hardening corrections, have the potential to provide simultaneous assessment of both micro-architecture and tissue mineralization. A second emerging modality for bone composition analysis is Fourier transform infrared microspectroscopic imaging (FTIRI), which provides complementary spatial measures of mineralization and mineral quality. The objective of this proposal is to develop a method for the simultaneous assessment of trabecular bone structure and composition incorporating microCT-based 3D mineralization data and FTIRI-derived 2D compositional information, and to utilize this method to investigate the effects of osteoporosis progression in human subjects. Relationships among mineralization measures and morphological features will be investigated. Once established, this technique will provide a powerful tool in bone quality studies, for example in quantifying changes in mineralization associated with age, disease, or drug treatment, determining spatial mineralization patterns associated with bone turn-over mechanisms, or exploring relationships between mineral quality, tissue damage, & bone strength. ? ?