Synchrotron X-ray microtomography and magnified holotomography in biomedical research - applications to bone tissue and future perspectives

Orateur : Alexandra PACUREANU (Uppsala Universit, SWEDEN)

Three dimensional quantitative measurements of biological specimens at micrometer and nanometer length scales are becoming increasingly accessible with the advent of imaging techniques, marking the transition of the biomedical research into a new period. Synchrotron X-ray micro and nanotomography give access to previously unreachable details of the architecture and composition of biological specimens, such as bone tissue, or small model organisms. The phase contrast techniques, such as magnified holotomography, are particularly suited for biological tissue since they provide enhanced contrast and have the potential to reduce the absorbed radiation dose, as compared to attenuation based X-ray imaging. This creates opportunities to unravel function of cells and tissue, opening pathways to improved strategies for treatment and prevention of diseases with high societal impact. We have shown that magnified holotomography enables simultaneously to quantify the 3D morphology of the bone osteocyte cell network, and the 3D organization and composition of collagen fibres in the surrounding extracellular matrix. This, combined with numerical methods, could clarify how bone tissue is locally regulated, which is an important milestone towards understanding pathways of diseases such as osteoporosis, metastatic bone cancer or bisphosphonate induced osteonecrosis. Understanding bone tissue regulation is also a prerequisite for design of the future biomaterials. In order to be able to fully exploit the created data, image processing and analysis techniques are often necessary. For example, the interconnected cell network in bone has a complex 3D architecture which cannot be described without appropriate methods of image segmentation and quantification. We have developed such methods, which permit to obtain relevant measurements bridging the gap between the reconstructed images and the answers to biological questions.

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