3D X-ray microscopy by absorption and phase Computerized Tomography

International audienceThere is currently a growing interest in 3D microscopic imaging techniques. In this presentation,we show the potential of synchrotron based 3D X-ray micro-CT and phase nano-CT for the exploration of living tissue up to the cellular scale [1] [2].These developments rely on the rapid spreading out of computerized tomography (CT) techniques from clinical imaging to pre-clinical and biological imaging. X-ray micro-CT systems made commercially available have received applications in a huge number of fields (biology/medicine, material science, industry, environment...). Another very promising field is phase contrast imaging, which is a coherent imaging technique improving the sensitivity of X-rays by exploiting another mode of contrast than absorption. We will particularly present micro/nano-CT based on synchrotron radiation (SR) and their advantages in terms of image quality over systems using standard X-ray sources, as well as the setups developed at ESRF (European Synchrotron Radiation Facility), Grenoble, France. We will also describe the data processing steps involved in the image formation process [3] and image analysis.We will focus on applications of these methods for the multiscale characterization of bone tissue. While micro-CT permit a detailed analysis of bone micro architecture in terms of geometry and mineralization with spatial resolution of a few micrometers, phase nano-CT permit to investigate in details the lacuno-canalicular network (LCN) embedding the osteocyte system in bone with spatial resolution of a few tenth of nanometers. According to the setup, it is possible either to obtain a global assessment of the LCN in entire osteons or a detailed analysis around a few cells. Moreover, phase nano-CT permit to quantify locally the mineralization of the extra cellular matrix as well as to get information about the organization of the collagen fibers constituting the bone matrix. 1] Pacureanu A, Langer M, Boller E, Tafforeau P, Peyrin F. Med Phys 2012;39:2229. [2] Langer M, Pacureanu A, Suhonen H, Grimal Q, Cloetens P, Peyrin F. PLoS ONE 2012;7:e35691. [3] Yu B, Weber L, Pacureanu A, Langer M, Olivier C, Cloetens P, Peyrin F, Optics Express 2018 in pres