We present the first ex vivo images of fresh, native breast tissue obtained from mastectomy specimens using grating interferometry. This technique yields improved diagnostic capabilities when compared with conventional mammography, especially when discerning the type of malignant conversions and their breadth within normal breast tissue. These promising results advance us toward the ultimate goal, using grating interferometry in vivo on humans in a clinical setting.

It is known that the sensitivity of X-ray phase-contrast grating interferometry with regard to electron density variations present in the sample is related to the minimum detectable refraction angle. In this article a numerical framework is developed that allows for a realistic and quantitative determination of the sensitivity. The framework is validated by comparisons with experimental results and then used for the quantification of several influences on the sensitivity, such as spatial coherence or the number of phase step images. In particular, we identify the ideal inter-grating distance with respect to the highest sensitivity for parallel beam geometry. This knowledge will help to optimize existing synchrotron-based grating interferometry setups. Abstract: It is known that the sensitivity of X-ray phase-contrast grating interferometry with regard to electron density variations present in the sample is related to the minimum detectable refraction angle. In this article a numerical framework is developed that allows for a realistic and quantitative determination of the sensitivity. The framework is validated by comparisons with experimental results and then used for the quantification of several influences on the sensitivity, such as spatial coherence or the number of phase step images. In particular, we identify the ideal intergrating distance with respect to the highest sensitivity for parallel beam geometry. This knowledge will help to optimize existing synchrotron-based grating interferometry setups. References and links1. U. Bonse and M. Hart, "An X-ray interferometer," Appl. Phys. Lett. 6, 155-156 (1965). 2. A. Momose, T. Takeda, Y. Itai, and K. Hirano, "Phase-contrast x-ray computed tomography for observing biological soft tissues," Nat. Med. 2, 473-475 (1996). 3. A. Yoneyama, T. Takeda, Y. Tsuchiya, J. Wu, T.-T. Lwin, A. Koizumi, K. Hyodo, and Y. Itai, "A phase-contrast X-ray imaging system-with a 60 x 30 mm field of view based on a skew-symmetric two-crystal X-ray interferometer," Nucl. Instrum. Methods Phys. Res. A 523, 217-222 (2004). 4. A. Snigirev, I. Snigireva, V. Kohn, S. Kuznetsov, and I. Schelokov, "On the possibilities of x-ray phase contrast microimaging by coherent high-energy synchrotron radiation," Rev. Sci. Instrum. 66, 5486-5492 (1995). 5. P. Cloetens, R. Barrett, J. Baruchel, J.-P. Guigay, and M. Schlenker, "Phase objects in synchrotron radiation hard x-ray imaging," J.

Phase retrieval from unidirectional radiographic differential phase contrast images requires integration of noisy data. A method is presented, which aims to suppress stripe artifacts arising from direct image integration. It is purely algorithmic and therefore, compared to alternative approaches, neither additional alignment nor an increased scan time is required. We report on the theory of this method and present results using numerical as well as experimental data. The method shows significant improvements on the phase retrieval accuracy and enhances contrast in the phase image. Due to its general applicability, the proposed method provides a valuable tool for various 2D imaging applications using differential data. Abstract:Phase retrieval from unidirectional radiographic differential phase contrast images requires integration of noisy data. A method is presented, which aims to suppress stripe artifacts arising from direct image integration. It is purely algorithmic and therefore, compared to alternative approaches, neither additional alignment nor an increased scan time is required. We report on the theory of this method and present results using numerical as well as experimental data. The method shows significant improvements on the phase retrieval accuracy and enhances contrast in the phase image. Due to its general applicability, the proposed method provides a valuable tool for various 2D imaging applications using differential data. References and links1. R. Fitzgerald, "Phase-sensitive X-ray imaging," Phys. Today 53, 23-26 (2000). 2. A. Momose and J. Fukuda, "Phase-contrast radiographs of nonstained rat cerebellar specimen," Med. Phys. 22, 375-379 (1995). 3. A. Snigirev, I. Snigireva, V. Kohn, S. Kuznetsov, and I. Schelokov, "On the possibilities of X-ray phase contrast microimaging by coherent high-energy synchrotron radiation," Rev. Sci. Instrum. 66, 5486-5492 (1995). 4. S. Wilkins, T.

X-ray grating interferometry is a promising imaging technique sensitive to attenuation, refraction and scattering of the radiation. Applications of this technique in the energy range between 80 and 150 keV pose severe technical challenges, and are still mostly unexplored. Phase-contrast X-ray imaging at such high energies is of relevant scientific and industrial interest, in particular for the investigation of strongly absorbing or thick materials as well as for medical imaging. Here we show the successful implementation of a Talbot-Lau interferometer operated at 100 keV using a conventional X-ray tube and a compact geometry, with a total length of 54 cm. We present the edge-on illumination of the gratings in order to overcome the current fabrication limits. Finally, the curved structures match the beam divergence and allow a large field of view on a short and efficient setup.

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We present a comparison for high-resolution imaging with a laboratory source between grating-based (GBI) and propagation-based (PBI) x-ray phase-contrast imaging. The comparison is done through simulations and experiments using a liquid-metal-jet x-ray microfocus source. Radiation doses required for detection in projection images are simulated as a function of the diameter of a cylindrical sample. Using monochromatic radiation, simulations show a lower dose requirement for PBI for small object features and a lower dose for GBI for larger object features. Using polychromatic radiation, such as that from a laboratory microfocus source, experiments and simulations show a lower dose requirement for PBI for a large range of feature sizes. Tested on a biological sample, GBI shows higher noise levels than PBI, but its advantage of quantitative refractive index reconstruction for multi-material samples becomes apparent.

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Abstract. This article illustrates the phase contrast instrumentation installed at the Tomographic Microscopy and Coherent Radiology beamline (TOMCAT) of the Swiss Light Source. Our experimental framework has been designed to extract phase information at spatial resolutions covering three orders of magnitude. For moderate (5-10 microns) resolutions we implemented a two-gratings interferometer, operated at energies between 14 and 40 keV. For high resolution (1-5 microns) we obtain phase information thanks to a modified transport of intensity approach. For very high-resolutions (0.1-0.5 microns) we developed a broadband hard X-ray full-field microscope operated in Zernikephase contrast.