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Coherent X‐ray imaging techniques, such as in‐line holography, exploit the high brilliance provided by diffraction‐limited storage rings to perform imaging sensitive to the electron density through contrast due to the phase shift, rather than conventional attenuation contrast. Thus, coherent X‐ray imaging techniques enable high‐sensitivity and low‐dose imaging, especially for low‐atomic‐number (Z) chemical elements and materials with similar attenuation contrast. Here, the first implementation of in‐line holography at the NanoMAX beamline is presented, which benefits from the exceptional focusing capabilities and the high brilliance provided by MAX IV, the first operational diffraction‐limited storage ring up to approximately 300 eV. It is demonstrated that in‐line holography at NanoMAX can provide 2D diffraction‐limited images, where the achievable resolution is only limited by the 70 nm focal spot at 13 keV X‐ray energy. Also, the 3D capabilities of this instrument are demonstrated by performing holotomography on a chalk sample at a mesoscale resolution of around 155 nm. It is foreseen that in‐line holography will broaden the spectra of capabilities of MAX IV by providing fast 2D and 3D electron density images from mesoscale down to nanoscale resolution. [ABSTRACT FROM AUTHOR]

Full‐field transmission X‐ray microscopy (TXM) is a well established technique, available at various synchrotron beamlines around the world as well as by laboratory benchtop devices. One of the major TXM challenges, due to its nanometre‐scale resolution, is the overall instrument stability during the acquisition of the series of tomographic projections. The ability to correct for vertical and horizontal distortions of each projection image during acquisition is necessary in order to achieve the effective 3D spatial resolution. The effectiveness of such an image alignment is also heavily influenced by the absorption properties and strong contrast of specific features in the scanned sample. Here it is shown that nanoporous gold (NPG) can be used as an ideal 3D test pattern for evaluating and optimizing the performance of a TXM instrument for hard X‐rays at a synchrotron beamline. Unique features of NPG, such as hierarchical structures at multiple length scales and high absorbing capabilities, makes it an ideal choice for characterization, which involves a combination of a rapid‐alignment algorithm applied on the acquired projections followed by the extraction of a set of both 2D‐ and 3D‐descriptive image parameters. This protocol can be used for comparing the efficiency of TXM instruments at different synchrotron beamlines in the world or benchtop devices, based on a reference library of scanned NPG samples, containing information about the estimated horizontal and vertical alignment values, 2D qualitative parameters and quantitative 3D parameters. The possibility to tailor the ligament sizes of NPG to match the achievable resolution in combination with the high electron density of gold makes NPG an ideal 3D test pattern for evaluating the status and performance of a given synchrotron‐based or benchtop‐based TXM setup. Nanoporous gold is hereby proposed as an ideal 3D pattern for characterizing the performance of hard X‐ray nano‐imaging systems. While a wide range of techniques such as ptychography, holography or other forms of nano‐probes will benefit from this development, here its utility is demonstrated by characterizing the transmission X‐ray microscope at beamline P05, DESY, which is a full‐field technique. [ABSTRACT FROM AUTHOR]

Lung imaging in mouse disease models is crucial for the assessment of the severity of airway disease but remains challenging due to the small size and the high porosity of the organ. Synchrotron inline free-propagation phase-contrast computed tomography (CT) with its intrinsic high soft-tissue contrast provides the necessary sensitivity and spatial resolution to analyse the mouse lung structure in great detail. Here, this technique has been applied in combination with single-distance phase retrieval to quantify alterations of the lung structure in experimental asthma mouse models of different severity. In order to mimic an in vivo situation as close as possible, the lungs were inflated with air at a constant physiological pressure. Entire mice were embedded in agarose gel and imaged using inline free-propagation phase-contrast CT at the SYRMEP beamline (Synchrotron Light Source, `Elettra', Trieste, Italy). The quantification of the obtained phase-contrast CT data sets revealed an increasing lung soft-tissue content in mice correlating with the degree of the severity of experimental allergic airways disease. In this way, it was possible to successfully discriminate between healthy controls and mice with either mild or severe allergic airway disease. It is believed that this approach may have the potential to evaluate the efficacy of novel therapeutic strategies that target airway remodelling processes in asthma. [ABSTRACT FROM AUTHOR]

Functionalized computed tomography (CT) in combination with labelled cells is virtually non-existent due to the limited sensitivity of X-ray-absorption-based imaging, but would be highly desirable to realise cell tracking studies in entire organisms. In this study we applied in-line free propagation X-ray phase-contrast CT (XPCT) in an allergic asthma mouse model to assess structural changes as well as the biodistribution of barium-labelled macrophages in lung tissue. Alveolar macrophages that were barium-sulfate-loaded and fluorescent-labelled were instilled intratracheally into asthmatic and control mice. Mice were sacrificed after 24 h, lungs were kept in situ, inflated with air and scanned utilizing XPCT at the SYRMEP beamline (Elettra Synchrotron Light Source, Italy). Single-distance phase retrieval was used to generate data sets with ten times greater contrast-to-noise ratio than absorption-based CT (in our setup), thus allowing to depict and quantify structural hallmarks of asthmatic lungs such as reduced air volume, obstruction of airways and increased soft-tissue content. Furthermore, we found a higher concentration as well as a specific accumulation of the barium-labelled macrophages in asthmatic lung tissue. It is believe that XPCT will be beneficial in preclinical asthma research for both the assessment of therapeutic response as well as the analysis of the role of the recruitment of macrophages to inflammatory sites. [ABSTRACT FROM AUTHOR]

Background In recent years, there has been interest on the fabrication of systems using particulates or block-based approach for bone tissue engineering ( TE) scaffolds, possessing porous interconnected structures. In fact, these particular morphologies greatly increase the surface area for more chemical and biological reactions to take place. Purpose This study was designed to demonstrate the unique capability of the synchrotron radiation x-ray microtomography (micro- CT) in offering an advanced characterization of coralline-derived (Biocoral) biomaterials placed in human maxillary defects as it allows, in a nondestructive way, a complete, precise, and high-resolution three-dimensional analysis of their microstructural parameters. Moreover, the comparison between Biocoral and other biomaterials was explored to understand the mechanism of their biological behavior as bone substitute. Materials and Methods Implant survival, bone regeneration, graft resorption, neovascularization, and morphometric parameters (including anisotropy and connectivity index of the structures) were evaluated by micro- CT in Biocoral and the other biomaterials after 6 to 7 months from implantation in human maxillary bone defects. Results After the in vivo tests, a huge amount of bone was detected in the retrieved Biocoral-based samples, coupled with a good rate of biomaterial resorption and the formation of a homogeneous and rich net of new vessels. The morphometric parameters were comparable to those obtained in the biphasic calcium phosphate-based control, with the exception of the connectivity index for which this control exhibited the most well-connected structure. This last result, together with those referred to the poor performances of the β-tricalcium phosphate block-based sample, suggests that the particular scaffold morphology may play a role in the hunt the optimal scaffold structure to be implanted. Conclusion In this limited study, implant success rate seems not strictly dependent on the biomaterial that is used, but on the scaffold morphology. Micro- CT technique was demonstrated to play a fundamental role in advanced characterization of bone TE constructs. [ABSTRACT FROM AUTHOR]

Propagation-based X-ray phase-contrast computed tomography (PBI) has already proven its potential in a great variety of soft-tissue-related applications including lung imaging. However, the strong edge enhancement, caused by the phase effects, often hampers image segmentation and therefore the quantitative analysis of data sets. Here, the benefits of applying single-distance phase retrieval prior to the three-dimensional reconstruction (PhR) are discussed and quantified compared with three-dimensional reconstructions of conventional PBI data sets in terms of contrast-to-noise ratio (CNR) and preservation of image features. The PhR data sets show more than a tenfold higher CNR and only minor blurring of the edges when compared with PBI in a predominately absorption-based set-up. Accordingly, phase retrieval increases the sensitivity and provides more functionality in computed tomography imaging. [ABSTRACT FROM AUTHOR]