Nowadays, X-ray tube-based high-resolution CT systems are widely used in scientific research and industrial applications. But the potential, convenience and economy of these lab systems is often underestimated. The present paper shows the comparison of sophisticated conventional μCT with synchrotron radiation-based μCT (SRμCT). The different aspects and characteristics of both approaches like spatial and density resolution, penetration depth, scanning time or sample size is described in detail. The tube-based μCT measurements were performed with a granite-based
nanotom®-CT system (phoenix|x-ray, Wunstorf, Germany) equipped with a 180 kV - 15 W high-power nanofocus® tube with tungsten or molybdenum targets. The tube offers a wide range of applications from scanning low absorbing samples in nanofocus® mode with voxel sizes below 500 nm and highly absorbing objects in the high power mode with focal spot and voxel sizes of a few microns. The SRμCT measurements were carried out with the absorption contrast set-up
at the beamlines W 2 and BW 2 at HASYLAB/DESY, operated by the GKSS Research Center. The range of samples examined covers materials of very different absorption levels and related photon energies for the CT scans. Both quantitative and qualitative comparisons of CT scans using biomedical specimens with rather low X-ray absorption such
as parts of the human spine as well as using composites from the field of materials science are shown.
Investigations of bony tissues are often performed using micro computed tomography based on X-rays, since the calcium distribution leads to superior contrast. Osteoporotic bone, for example, can be well compared with healthy one with respect to density and morphology. Degenerative and rheumatoid diseases usually start, however, at the bone-cartilage-interface, which is hardly accessible. The direct influence on the bone itself becomes only visible at later stage. For the development of suitable therapies against degenerative cartilage damages the exact three-dimensional description of the
bone-cartilage interface is vital, as demonstrated for transplanted cartilage-cells or bone-cartilage-constructs in animal models. So far, the morphological characterization was restricted to magnetic resonance imaging (MRI) with poor spatial resolution or to time-consuming histological sectioning with appropriate spatial resolution only in two rather arbitrarily chosen directions. Therefore, one should develop μCT to extract the features of low absorbing cartilage. The morphology and the volume of the inter-vertebral cartilage disc of lumbar motion segments have been determined for one PMMA embedded specimen. Tomograms were recorded using nanotom® (Phoenix|x-ray, Wunstorf, Germany), μCT 35<sup>TM</sup>
(Scanco Medical, Brütisellen, Switzerland), 1172<sup>TM</sup> and 1174<sup>TM</sup> (both Skyscan, Kontich, Belgium), as well as using the
SRμCT at HASYLAB/DESY. Conventional and SRμCT can provide the morphology and the volume of cartilage between bones. Increasing the acquisition time, the signal-to-noise ratio becomes better and better but the prominent artifacts in conventional μCT as the result of inhomogeneously distributed bony tissue prevents the exact segmentation of cartilage. SRμCT allows segmenting the cartilage but requires long periods of expensive beam-time to obtain