3D COMPUTED X-RAY TOMOGRAPHY OF HUMAN CANCELLOUS BONE AT 8 MU-M SPATIAL AND 10(-4) ENERGY RESOLUTION

Human cancellous bone was imaged and its absorptive density accurately measured in three dimensions (3D), nondestructively and at high spati al resolution by means of computerized microtomography (mu CT). Essent ial for achieving the resolution and accuracy was the use of monoenerg etic synchrotron radiation (SR) which avoided beam hardening effects, secured excellent contrast conditions including the option of energy-m odulated contrast, and yet provided high intensity. To verify the reso lution, we selected objects of similar to 8 mu m size that could be ob served on tomograms and correlated them in a unique manner to their co unter images seen in histological sections prepared from the same spec imen volume. Thus we have shown that the resolution expected from the voxel size of 8 mu m used in the mu CT process is in effect also attai ned in our results. In achieving the present results no X-ray-optical magnification was used. From mu CT studies of composites (Bonse et al. , X-ray tomographic microscopy (XTM) applied to carbon-fibre composite s. In: Materlik G, ed. HASYLAB Jahresbericht 1990. Hamburg: DESY, 1990 ;567-568) we know that by including X-ray magnification a resolution b elow 2 mu m is obtained. Therefore, with foreseeable development of ou r mu CT method, the 3D and nondestructive investigation of structures in mineralized bone on the 2 mu m level is feasible. For example, it s hould be possible to study tomographically the 3D distribution and amo unt of osteoclastic resorption in the surrounding bone structure.