How cryo-SXT works

X-rays pass through a biological sample and are partially attenuated based on carbon content (carbon-rich biological structures absorb soft X-rays preferentially). The generated projections are recorded at small angular increments to create a tilt series of images that provide structural information at different orientations. 

 

These are then reconstructed into tomograms, the cellular equivalent of CT scans used in hospitals, to produce a 3D image.  Other techniques can be used, in correlation with tomography, to zoom in on specific areas of interest and fully interrogate the data.  This is most powerful in combination with high resolution fluorescence microscopy (cryoSIM) allowing identification and location of cell components (and other species).