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LMN

LMN. SLS.

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LMN

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  1. LMN SLS Phase Contrast X-Ray Radiography and Tomography Based on a Grating Interferometer C. David, T. Weitkamp, A. DiazLaboratory for Micro- and Nanotechnology (LMN), Paul Scherrer Institut, Switzerland F. Pfeiffer, M. Stampanoni, J.F. van der Veen Swiss Light Source (SLS), Paul Scherrer Institut, Switzerland C. David, IEEE Conference, Rome, 21.10.2004

  2. X-rays for medical imaging • Minimizing the radiation dose is an important issue – especially in mammography • low absorption contrast • => large dose required to obtain sufficiently good S/N • low applied photon energy (Mo anodes) • screening submits a large number of healthy patients to radiation dose C. David, IEEE Conference, Rome, 21.10.2004

  3. Improving contrast Source Detector Sample C. David, IEEE Conference, Rome, 21.10.2004

  4. Improving contrast Source Detector Sample efficiency, size, resolution C. David, IEEE Conference, Rome, 21.10.2004

  5. Improving contrast Source Detector Sample spectrum, power, coherence efficiency, size, resolution C. David, IEEE Conference, Rome, 21.10.2004

  6. Improving contrast Source Detector Sample spectrum, power, coherence contrast mechanism efficiency, size, resolution C. David, IEEE Conference, Rome, 21.10.2004

  7. Phase contrast vs. amplitude contrast n = 1 – d + ib x-rays C. David, IEEE Conference, Rome, 21.10.2004

  8. Phase contrast vs. amplitude contrast n = 1 – d + ib x-rays C. David, IEEE Conference, Rome, 21.10.2004

  9. Phase contrast vs. amplitude contrast n = 1 – d + ib x-rays C. David, IEEE Conference, Rome, 21.10.2004

  10. Phase contrast vs. amplitude contrast n = 1 – d + ib x-rays • Example: • 20 keV • Organic sample (polymer, biological, medical…) . • 50 mm thickness C. David, IEEE Conference, Rome, 21.10.2004

  11. Phase contrast vs. amplitude contrast n = 1 – d + ib x-rays • Example: • 20 keV • Organic sample (polymer, biological, medical…) . • 50 mm thickness •  only 0.2 % absorption, but p- phase shift C. David, IEEE Conference, Rome, 21.10.2004

  12. + Phase contrast vs. amplitude contrast n = 1 – d + ib x-rays • Example: • 20 keV • Organic sample (polymer, biological, medical…) . • 50 mm thickness •  only 0.2 % absorption, but p- phase shift C. David, IEEE Conference, Rome, 21.10.2004

  13. + Phase contrast vs. amplitude contrast n = 1 – d + ib x-rays • Example: • 20 keV • Organic sample (polymer, biological, medical…) . • 50 mm thickness •  only 0.2 % absorption, but p- phase shift •  much higher contrast  less dose required C. David, IEEE Conference, Rome, 21.10.2004

  14. Hard x-ray interferometry detector Object Bonse-Hart Interferometer (since 1965) C. David, IEEE Conference, Rome, 21.10.2004

  15. Hard x-ray interferometry detector Object Bonse-Hart Interferometer (since 1965) • Object beam and reference beam are generated by Bragg reflections on thin Si crystals • The interference of both beams gives a phase image C. David, IEEE Conference, Rome, 21.10.2004

  16. Hard x-ray interferometry detector Object Bonse-Hart Interferometer (since 1965) • optical path length difference needs to be stable to a fraction of a wavelengths • picometer stability required • cannot be scaled up • Object beam and reference beam are generated by Bragg reflections on thin Si crystals • The interference of both beams gives a phase image C. David, IEEE Conference, Rome, 21.10.2004

  17. Propagation methods – edge contrast C. David, IEEE Conference, Rome, 21.10.2004

  18. Propagation methods – edge contrast • phase shift greatly enhances contrast of edges • can be used to retrieve phase information • requires high degree of transverse coherence (i.e. small source size) • cannot be scaled up to large fields of view (required detector resolution) C. David, IEEE Conference, Rome, 21.10.2004

  19. Grating x-ray interferometry 50 nm C. David, IEEE Conference, Rome, 21.10.2004

  20. beam-splitter phase grating s Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  21. beam-splitter phase grating s Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  22. beam-splitter phase grating s interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  23. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  24. beam-splitter phase grating analyzer amplitude grating camera interference pattern Moiré fringes Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  25. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  26. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  27. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  28. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  29. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  30. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  31. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  32. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  33. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  34. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  35. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  36. beam-splitter phase grating analyzer amplitude grating camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  37. beam-splitter phase grating analyzer amplitude grating phase object camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  38. beam-splitter phase grating analyzer amplitude grating phase object camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  39. beam-splitter phase grating analyzer amplitude grating phase object camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  40. beam-splitter phase grating analyzer amplitude grating phase object camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  41. beam-splitter phase grating analyzer amplitude grating phase object camera interference pattern Grating x-ray interferometry C. David, IEEE Conference, Rome, 21.10.2004

  42. beam-splitter phase grating analyzer amplitude grating phase object camera interference pattern Grating x-ray interferometry Differential phase contrast imaging! C. David, IEEE Conference, Rome, 21.10.2004

  43. The gratings Phase grating (silicon, p = 4 µm) 4 µm 4 µm 4 µm • Si-110 wet-etched • Depth of structures chosen so that phase shift is π no zeroth order C. David, IEEE Conference, Rome, 21.10.2004

  44. The gratings Absorption grating (Au in silicon, q = 2 µm) Phase grating (silicon, p = 4 µm) 4 µm 4 µm 4 µm 4 µm 4 µm • Si-110 wet-etched • Depth of structures chosen so that phase shift is π no zeroth order • Au in gaps of Si grating • Grown electrochemically • Period is half that of the phase grating C. David, IEEE Conference, Rome, 21.10.2004

  45. polystyrene spheres Ø 100 and 200 µm Photon energy: 12.4 keV p = 4 µm q = 2 µm BM 5, ESRF, Dec. 2002 C. David, IEEE Conference, Rome, 21.10.2004

  46. Interferometric phase contrast Absorption contrast andedge contrast C. David, IEEE Conference, Rome, 21.10.2004

  47. Interferometric phase contrast Absorption contrast andedge contrast Differential phase contrast C. David, IEEE Conference, Rome, 21.10.2004

  48. Interferometric phase contrast Absorption contrast andedge contrast Differential phase contrast Phase contrast Can be integrated to yield projected phase shift of sample  Suited for tomographic reconstruction C. David, IEEE Conference, Rome, 21.10.2004

  49. Edge contrast vs. Interferometric contrast Non-interferometric Absorption and Edge contrast 0.5mm Projection Tomogram C. David, IEEE Conference, Rome, 21.10.2004

  50. Edge contrast vs. Interferometric contrast Non-interferometric Interferometric phase contrast Absorption and Edge contrast Phase gradient Phase 0.5mm Projection Projection Projection ID19, ESRF, June 2004 14.4 keV Tomogram Tomogram C. David, IEEE Conference, Rome, 21.10.2004

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