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BP: Fachverband Biologische Physik
BP 7: Poster I
BP 7.42: Poster
Montag, 23. März 2009, 17:45–20:00, P3
Phase contrast tomography of human brain using grating interferometry — •Georg Schulz1, Marco Germann1, Franz Pfeiffer2, Timm Weitkamp3, Christian David2, and Bert Müller1 — 1Biomaterials Science Center, University Basel, Switzerland — 2Paul Scherrer Institute Villigen, Switzerland — 3ID19, ESRF Grenoble, France
In order to visualize the human thalamus, which is one of the most ambitious challenges in X-ray tomography, as it exhibits almost no absorption contrast, we use phase contrast tomography which is based on differences of the refraction index. No labelling of the tissue before the measurements is needed in order to segment the vessel tree from the surrounding tissue. In our study we use a grating interferometer consisting of a beam-splitter grating and an analyzer absorption grating. Here we can detect phase shifts in the range of several 10−8 rad. The presented results derive from measurements at ESRF Grenoble (beamline ID19) at an energy of 26 keV. The resulting voxel sizes range down to 7.5 µ m. The examination of the reconstructed tomographic slices implies a measurement sensitivity for the real part of the refractive index of 0.7·10−10, which corresponds to an electron density sensitivity of 0.04 e/nm3 and a mass density sensitivity of approximately 0.1 mg/cm3 for aqueous specimens. Blood vessels could be well identified and partially segmented using a simple intensity based segmentation tool. For a complete segmentation more sophisticated tools are needed.