The rapid development of high-brilliance X-ray sources in the last decades has opened the way to extremely powerful X-ray imaging modalities. In order to make the most of X-ray’s high penetration power, it is best to combine these novel imaging approaches with computed tomography to achieve high-sensitivity 3D imaging of a variety of life-science samples at the nanometer scale. The further development of these methods and their application to MAP-relevant scientific questions, i.e. the visualization of bone and tumour microstructure for understanding the development of cancer and osteoporosis in an early stage, represent the main goals of this project.
A recent demonstration of ptychographic nano computed tomography (nano-CT) showed that the technique can produce high-contrast, high-resolution three-dimensional density maps at the sub-100-nm length scale. The technique exploits the phase-contrast signal from the imaged sample to produce quantitative electron density maps with unprecedented sensitivity.
In this project ptychographic nano-CT will be used to study slight variations in mineral density in the vicinity of osteocytes (bone cells) to identify the main mechanisms causing demineralisation in the bulk of the bone matrix. The 3D electron density recovered by tomographic reconstruction will allow detecting small gradients over sub-micron distances in the vicinity of cell lacunae and the canalicular network.
In a first phase of the project, ovine and human bone samples will be imaged using existing synchrotron sources. In a second phase, ptychographic nano-CT will be implemented at TUM using the high-brilliance sources that will soon be available at the new Centre for Advanced Laser Applications (CALA). In parallel to the bone research project techniques will be developed to fix other tissues having biomedical relevance, such as small samples from human biopsies, to allow them to sustain the high radiation dose required for high-resolution X-ray imaging.