[Andrews, Joy C.
; Pianetta, Piero] SLAC Natl Accelerator Lab, Stanford Synchrotron Radiat Lightsource, Menlo Pk, CA 94025 USA
; [Almeida, Eduardo] NASA, Ames Res Ctr, Moffett Field, CA 94035 USA
; [van der Meulen, Marjolein C. H.] Cornell Univ, Sibley Sch Mech & Aerosp Engn, Ithaca, NY 14853 USA
; [Alwood, Joshua S.] Stanford Univ, Dept Aeronaut & Astronaut, Stanford, CA 94305 USA
; [Lee, Chialing] San Jose State Univ, Dept Biol Sci, San Jose, CA 95192 USA
; [Liu, Yijin] Inst High Energy Phys, Beijing 100039, Peoples R China
; [Chen, Jie] Univ Sci & Technol China, Natl Synchrotron Radiat Lab, Hefei 230026, Peoples R China
; [Meirer, Florian] Vienna Univ Technol, Inst Atom & Subatom Phys, Vienna, Austria
; [Feser, Michael
; Gelb, Jeff
; Rudati, Juana
; Tkachuk, Andrei
; Yun, Wenbing] Xradia Inc, Concord, CA 94520 USA
A novel hard transmission X-ray microscope (TXM) at the Stanford Synchrotron Radiation Light-source operating from 5 to 15 keV X-ray energy with 14 to 30 mu m(2) field of view has been used for high-resolution (30-40 nm) imaging and density quantification of mineralized tissue. TXM is uniquely suited for imaging of internal cellular structures and networks in mammalian mineralized tissues using relatively thick (50 mu m), untreated samples that preserve tissue micro-and nanostructure. To test this method we performed Zernike phase contrast and absorption contrast imaging of mouse cancellous bone prepared under different conditions of in vivo loading, fixation, and contrast agents. In addition, the three-dimensional structure was examined using tomography. Individual osteocytic lacunae were observed embedded within trabeculae in cancellous bone. Extensive canalicular networks were evident and included processes with diameters near the 30-40 nm instrument resolution that have not been reported previously. Trabecular density was quantified relative to rod-like crystalline apatite, and rod-like trabecular struts were found to have 51-54% of pure crystal density and plate-like areas had 44-53% of crystal density. The nanometer resolution of TXM enables future studies for visualization and quantification of ultrastructural changes in bone tissue resulting from osteoporosis, dental disease, and other pathologies.