C. David, IEEE Conference, Rome, 21.10.2004 Phase Contrast X-Ray Radiography and Tomography Based on a Grating Interferometer C. David, T. Weitkamp, A. Diaz Laboratory 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 LMN SLS C. David, IEEE Conference, Rome, 21.10.2004

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

C. David, IEEE Conference, Rome, 21.10.2004 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

C. David, IEEE Conference, Rome, 21.10.2004 The gratings Phase grating (silicon, p = 4 µm) Absorption grating (Au in silicon, q = 2 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

C. David, IEEE Conference, Rome, 21.10.2004 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

Interferometric phase contrast Absorption contrast and edge contrast C. David, IEEE Conference, Rome, 21.10.2004

Interferometric phase contrast Absorption contrast and edge contrast Differential phase contrast C. David, IEEE Conference, Rome, 21.10.2004

Interferometric phase contrast Absorption contrast and edge 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

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

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

C. David, IEEE Conference, Rome, 21.10.2004 0.5mm C. David, IEEE Conference, Rome, 21.10.2004

C. David, IEEE Conference, Rome, 21.10.2004 0.5 mm 1mm C. David, IEEE Conference, Rome, 21.10.2004

C. David, IEEE Conference, Rome, 21.10.2004 0.5 mm 1mm C. David, IEEE Conference, Rome, 21.10.2004

Polychromatic radiation C. David, IEEE Conference, Rome, 21.10.2004

Polychromatic radiation beam-splitter phase grating analyzer amplitude grating phase object camera λ1 interference pattern C. David, IEEE Conference, Rome, 21.10.2004

Polychromatic radiation beam-splitter phase grating analyzer amplitude grating phase object camera λ2 λ1 interference pattern C. David, IEEE Conference, Rome, 21.10.2004

Polychromatic radiation beam-splitter phase grating analyzer amplitude grating phase object camera λ2 λ1 interference pattern C. David, IEEE Conference, Rome, 21.10.2004

Polychromatic radiation beam-splitter phase grating analyzer amplitude grating phase object camera λ2 λ1 interference pattern C. David, IEEE Conference, Rome, 21.10.2004

Pink-beam phase tomography Beam conditioning: SLS wiggler No monochromator Zr absorption filter 100 µm Camera scintillator YAG: Y absorption edge at 17.0 keV acts as high-pass filter Mean energy E = 17.5 keV Bandwidth ΔE ≈ 1 keV C. David, IEEE Conference, Rome, 21.10.2004

Pink-beam phase tomography Beam conditioning: SLS wiggler No monochromator Zr absorption filter 100 µm Camera scintillator YAG: Y absorption edge at 17.0 keV acts as high-pass filter Mean energy E = 17.5 keV Bandwidth ΔE ≈ 1 keV Sample: Three fibers Polyamide Ø 225 µm Boron Ø 200 µm, core: W Ø 10 µm PBT Ø 190 µm C. David, IEEE Conference, Rome, 21.10.2004

Pink-beam phase tomography Edge contrast Sample: Three fibers Polyamide Ø 225 µm Boron Ø 200 µm, core: W Ø 10 µm PBT Ø 190 µm C. David, IEEE Conference, Rome, 21.10.2004

Pink-beam phase tomography Edge contrast Sample: Three fibers Polyamide Ø 225 µm Boron Ø 200 µm, core: W Ø 10 µm PBT Ø 190 µm Differential phase contrast C. David, IEEE Conference, Rome, 21.10.2004

Pink-beam phase tomography Edge contrast Sample: Three fibers Polyamide Ø 225 µm Boron Ø 200 µm, core: W Ø 10 µm PBT Ø 190 µm Differential phase contrast Phase contrast C. David, IEEE Conference, Rome, 21.10.2004

Pink-beam phase tomography Edge contrast tomogram Edge contrast Sample: Three fibers Polyamide Ø 225 µm Boron Ø 200 µm, core: W Ø 10 µm PBT Ø 190 µm Phase contrast tomogram Differential phase contrast Phase contrast C. David, IEEE Conference, Rome, 21.10.2004

Pink-beam phase tomography C. David, IEEE Conference, Rome, 21.10.2004

Required transverse coherence C. David, IEEE Conference, Rome, 21.10.2004

Required transverse coherence camera d C. David, IEEE Conference, Rome, 21.10.2004

Required transverse coherence camera d In our experiments: E = 17.5 keV, => l = 0.07nm d = 28mm, => s = 1mm C. David, IEEE Conference, Rome, 21.10.2004

Required transverse coherence camera d In our experiments: E = 17.5 keV, => l = 0.07nm d = 28mm, => s = 1mm Transverse coherence length c: c = l * p/s p: source distance, e.g. 2m s: source size, e.g. 100mm C. David, IEEE Conference, Rome, 21.10.2004

Required transverse coherence camera d In our experiments: E = 17.5 keV, => l = 0.07nm d = 28mm, => s = 1mm Transverse coherence length c: c = l * p/s = 1.4mm p: source distance, e.g. 2m s: source size, e.g. 100mm C. David, IEEE Conference, Rome, 21.10.2004

C. David, IEEE Conference, Rome, 21.10.2004 Summary C. David, IEEE Conference, Rome, 21.10.2004

C. David, IEEE Conference, Rome, 21.10.2004 Summary There is a large potential to reduce the x-ray dose in medical imaging by exploiting the phase shifting property of matter rather than the absorption C. David, IEEE Conference, Rome, 21.10.2004

C. David, IEEE Conference, Rome, 21.10.2004 Summary There is a large potential to reduce the x-ray dose in medical imaging by exploiting the phase shifting property of matter rather than the absorption Grating interferometry offers advantages compared to other phase imaging methods : C. David, IEEE Conference, Rome, 21.10.2004

C. David, IEEE Conference, Rome, 21.10.2004 Summary There is a large potential to reduce the x-ray dose in medical imaging by exploiting the phase shifting property of matter rather than the absorption Grating interferometry offers advantages compared to other phase imaging methods : Robustness Quantitative method Works fine at energies suitable for mammography Requires no temporal and little spatial coherence Has potential to be scaled up to large fields of view C. David, IEEE Conference, Rome, 21.10.2004

C. David, IEEE Conference, Rome, 21.10.2004 Acknowledgments Many thanks to: At PSI E. Deckardt F. Glaus B. Haas Y. Hemmerling L. Heyderman M. Lange J. Lehmann D. Meister T. Neiger B. Nöhammer T. Rohbeck At ESRF: P. Cloetens J. Hoszowska E. Ziegler and many others ... Funding: Swiss National Science Foundation European Community C. David, IEEE Conference, Rome, 21.10.2004

Postdoc Position available Acknowledgments Many thanks to: At PSI E. Deckardt F. Glaus B. Haas Y. Hemmerling L. Heyderman M. Lange J. Lehmann D. Meister T. Neiger B. Nöhammer T. Rohbeck At ESRF: P. Cloetens J. Hoszowska E. Ziegler and many others ... Funding: Swiss National Science Foundation European Community Postdoc Position available C. David, IEEE Conference, Rome, 21.10.2004