Phase Contrast and Dark-Field Imaging

Grating interferometry based hard X-ray phase contrast can provide superior contrast, especially in soft tissue, when compared to conventional attenuation based imaging. At the same time, grating interferometry also provides a dark-field image that can show details both in biomedial and material science applications.

Especially since the first demonstration of phase contrast imaging at a conventional X-ray tube source in our lab [1], X-ray grating interferometry has become a popular research subject. Further experiments at our lab sources include the demonstration of grating interferometry based dark-field imaging [2], as well as developments in biomedical imaging such as the phase-contrast tomography of an infant hand [3] as well as the clinical evaluation of grating interferometry in mammography applications [4].

In recent experiments at synchrotron sources, we have shown two ways of recording the full differential phase gradient vector. One approach, using tilted gratings works well in tomography using one-dimensional line grating structures and can lead to improved tomographic reconstructions [5] as shown for a saggital slice through a rat brain in Figure 1.

The other approach to record the full phase gradient vector is based on two-dimensional grating structures that can be fabricated using deep reactive ion etching. This approach is well suited to radiography and can provide a differential phase signal in two directions, as well as a directional dark-field signal [6,7]. An example of such a directional scattering image of an ant is shown in Figure 2. This method also has interesting applications in in-situ X-ray optics metrology.

Publications

[1] F. Pfeiffer, T. Weitkamp, O. Bunk, and C. David, Phase retrieval and differential phase-contrast imaging with low-brilliance X-ray sources, Nature Physics 2 (2006), 258-261. DOI: 10.1038/nphys265

[2] F. Pfeiffer, M. Bech, O. Bunk, P. Kraft, E. F. Eikenberry, Ch. Brönnimann, C. Grünzweig, and C. David, Hard X-ray dark-field imaging using a grating interferometer, Nature Materials 7 (2008), 134-137. DOI: 10.1038/nmat2096

[3] T. Donath, F. Pfeiffer, O. Bunk, C. Grünzweig, E. Hempel, S. Popescu, P. Vock, and C. David, Demonstration of Enhanced Soft-Tissue Contrast in Human Specimen, Investigative Radiology 45 (2010), 445-452. DOI: 10.1097/RLI.0b013e3181e21866

[4] M. Stampanoni, Z. Wang, T. Thüring, C. David, E. Roessl, M. Trippel, R. A. Kubik-Huch, G. Singer, M. K. Hohl, and N. Hauser, The First Analysis and Clinical Evaluation of Native Breast Tissue Using Differential Phase-Contrast Mammography, Investigative Radiology 46 (2011), 801-806. DOI: 10.1097/RLI.0b013e31822a585f

[5] S. Rutishauser, T. Donath, C. David, F. Pfeiffer, F. Marone, P. Modregger, and M. Stampanoni, A tilted grating interferometer for full vector field differential x-ray phase contrast tomography, Optics Express 19 (2011), 24890-24896. DOI: 10.1364/OE.19.024890 Open access PDF

[6] I. Zanette, T. Weitkamp, T. Donath, S. Rutishauser, and C. David, Two-Dimensional X-ray Grating Interferometer, Physical Review Letters 105 (2010), 248102. DOI: 10.1103/PhysRevLett.105.248102

[7] S. Rutishauser, M. Bednarzik, I. Zanette, T. Weitkamp, M. Börner, J. Mohr, and C. David, Fabrication of two-dimensional hard X-ray diffraction gratings, Microelectronics Engineering 101 (2013), 12-16. DOI: 10.1016/j.mee.2012.08.025

Contact

Dr. Christian David

Laboratory for Micro-
and Nanotechnology
Paul Scherrer Institut
5232 Villigen PSI
Switzerland

Telephone:
+41 56 310 3753
Telefax:
+41 56 310 2646
E-mail:
christian.david@psi.ch