Evaluation of different heavy-metal stains and embedding media for phase contrast tomography of neuronal tissue

In the present work, we evaluate and compare the contrast and resolution obtained on different neuronal tissues with propagation-based x-ray phase contrast computed tomography (PB-CT). At our laboratory-based liquid metal-jet setup, we obtain overview datasets at sub-micron resolution of mm3 -sized volumes. In order to evaluate these parameters down to the sub-cellular level, we utilize the synchrotron endstation GINIX at P10, DESY. At this dedicated endstation1 developed and operated by our group, we utilize x-ray waveguide optics for highresolution cone-beam scans at strong geometrical magnification M. Exploiting this multi-scale approach, we investigate the image quality of cerebellum tissue treated by different heavy-metal stains. In addition, we study the electron density contrast in unstained tissues. Different embedding media are utilized depending on the stain, which also significantly affects contrast and image quality. With this work, we want to contribute to an optimized sample preparation to study the neuronal architecture of the brain tissue in greater detail in three dimensions (3d)