X-ray diffraction microtomography using synchrotron radiation

The X-ray diffraction computed tomography technique is based on the interfe rence phenomena of the coherent scatter. For low-momentum transfer, it is m ost probable that the scattering interaction will be coherent. A selective discrimination of a given element in a scanned specimen can be realized by fixing the Bragg angle which produces an interference peak and then, to car ry out the computed tomography in the standard mode. The image reconstructe d exalts the presence of this element with respect to other ones in a sampl e. This work reports the feasibility of a nondestructive synchrotron radiat ion X-ray diffraction imaging technique. This research was performed at the X-ray Diffraction beam line of the National Synchrotron Light Laboratory ( LNLS) in Brazil. The coherent scattering properties of different tissue and bone substitute materials were evaluated. Furthermore, diffraction pattern s of some polycrystalline solids were studied due to industrial and environ mental human exposure to these metals. The obtained diffraction patterns fo rm the basis of a selective tomography technique. Preliminary images are pr esented. (C) 2001 Elsevier Science B.V. All rights reserved.