A tomography slice through the entire human brain with less than three micrometer voxels

Imaging anatomical features of the human brain at cellular resolution currently relies on series of physical sections with related slicing artefacts. So far, microtomography has been employed to image an entire human brain at a voxel size of 20µm and selected regions using 6µm. This study aims to demonstrate the feasibility of imaging the entire human brain with cellular resolution without the need for physical sectioning using hard x-ray computed tomography. 1.2mm high sections of two human brains, one embedded in ethanol, the other in paraffin, were imaged using microtomography at the P07 beamline at DESY, Hamburg, Germany with a monochromatic beam at 67keV. The extended field of view necessary to cover the ca. 10 cm wide specimens at 2.54µm voxel size was realized by projection tiling with eight to ten rings. The resulting reconstructed slices measured 39,000×39,000 voxels. This synchrotron radiation-based study shows the feasibility of employing x-ray tomography to image the entire human brain with isotropic voxels of 2.54µm resolution. Next, we need to tackle the vertical stitching of several 10,000 slices of 6GB each, posing the challenge of processing the big data of an entire PB-sized human brain and making it accessible to the research community.