Liebi, M. et al. Nature 527, 349–352 (2015).

Schaff, F. et al. Nature 527, 353–356 (2015).

Small-angle x-ray scattering (SAXS) is a powerful tool for imaging dense specimens at the nanoscale in two dimensions, but the generation of 3D reconstructions (also known as tomography) has been technically challenging with SAXS data. New work has overcome this hurdle to allow complete 3D imaging of dense biological samples. Schaff et al. used computed tomography with virtual tomography axes, which retained sample-orientation information that is normally lost and allowed for complete 3D mapping of collagen organization in tooth samples in real and reciprocal space. In separate work, Liebi et al. produced complete 3D reconstructions of collagen in bone samples by combining SAXS with tensor tomography. These methods pave the way for future 3D imaging of dense biological samples at the nanoscale.