A synchrotron radiation microtomography system for the analysis of trabecular bone samples

X-ray computed microtomography is particularly well suited for studying tra becular bone architecture, which requires three-dimensional (3-D) images wi th high spatial resolution. For this purpose, we describe a three-dimension al computed microtomography (mu CT) system using synchrotron radiation, dev eloped at ESRF. Since synchrotron radiation provides a monochromatic and hi gh photon flux x-ray beam, it allows high resolution and a high signal-to-n oise ratio imaging. The principle of the system is based on truly three-dim ensional parallel tomographic acquisition. It uses a two-dimensional (2-D) CCD-based detector to record 2-D radiographs of the transmitted beam throug h the sample under different angles of view. The 3-D tomographic reconstruc tion performed by an exact 3-D filtered backprojection algorithm, yields 3- D images with cubic voxels. The spatial resolution of the detector was expe rimentally measured. For the application to bone investigation, the voxel s ize was set to 6.65 mu m, and the experimental spatial resolution was found to be 11 mu m. The reconstructed linear attenuation coefficient was calibr ated from hydroxyapatite phantoms. Image processing tools are being develop ed to extract structural parameters quantifying trabecular bone architectur e from the 3-D mu CT images. First results on human trabecular bone samples are presented. (C) 1999 American Association of Physicists in Medicine. [S 0094-2405(99)01610-7].