Virtual speckle-based X-ray phase-contrast and dark-field imaging with digital phantoms
TL;DR: In this paper, the authors demonstrate two versatile, flexible, and accurate frameworks based on numerical and Monte Carlo approaches to simulate the X-ray speckle-based (SBI) technique for lab-based systems.
Abstract: We demonstrate two versatile, flexible, and accurate frameworks based on numerical and Monte Carlo approaches to simulate the X-ray speckle-based (SBI) technique for lab-based systems. The established tools can reproduce experimental setups in a cone-beam geometry and with polychromatic sources. Furthermore, they are computationally efficient to enable a fast virtual multi-modal tomography of digitized inhomogeneous phantoms. The proposed methods were evaluated and validated by analytical and experimental data for various samples. The Monte Carlo approach provides a realistic and accurate simulation, which is useful in diffuser design and dosimetry studies, while the numerical method is very efficient for parametric and tomographic studies. These approaches will be used for the optimization of lab-based X-ray SBI setups and generating sample images for enhancing phase retrieval algorithms.
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University of Genoa1, University of Manchester2, KEK3, CERN4, Imperial College London5, Stanford University6, Tata Institute of Fundamental Research7, Istituto Nazionale di Fisica Nucleare8, University of Pittsburgh9, Lyon College10, TRIUMF11, Northeastern University12, Thomas Jefferson National Accelerator Facility13, University of Córdoba (Spain)14, Goethe University Frankfurt15, University of Southampton16, University of Udine17, University of Alberta18, Tokyo Metropolitan University19, Helsinki Institute of Physics20, National Research Nuclear University MEPhI21, University of Bath22, Niigata University23, Naruto University of Education24, Kobe University25, University of Calabria26, University of Trieste27, European Space Agency28, University of Birmingham29, Ritsumeikan University30, Qinetiq31, École Polytechnique Fédérale de Lausanne32, Massachusetts Institute of Technology33, Brookhaven National Laboratory34
01 Jul 2003-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The Gelfant 4 toolkit as discussed by the authors is a toolkit for simulating the passage of particles through matter, including a complete range of functionality including tracking, geometry, physics models and hits.
Abstract: G eant 4 is a toolkit for simulating the passage of particles through matter. It includes a complete range of functionality including tracking, geometry, physics models and hits. The physics processes offered cover a comprehensive range, including electromagnetic, hadronic and optical processes, a large set of long-lived particles, materials and elements, over a wide energy range starting, in some cases, from 250 eV and extending in others to the TeV energy range. It has been designed and constructed to expose the physics models utilised, to handle complex geometries, and to enable its easy adaptation for optimal use in different sets of applications. The toolkit is the result of a worldwide collaboration of physicists and software engineers. It has been created exploiting software engineering and object-oriented technology and implemented in the C++ programming language. It has been used in applications in particle physics, nuclear physics, accelerator design, space engineering and medical physics.
18,904 citations
TL;DR: In this paper, the authors evaluated plasma heat shock protein (Hsp) 90 in the skin of patients with systemic sclerosis (SSc) and characterized its association with SSc-related features.
Abstract: Our previous study demonstrated increased expression of Heat shock protein (Hsp) 90 in the skin of patients with systemic sclerosis (SSc). We aimed to evaluate plasma Hsp90 in SSc and characterize its association with SSc-related features. Ninety-two SSc patients and 92 age-/sex-matched healthy controls were recruited for the cross-sectional analysis. The longitudinal analysis comprised 30 patients with SSc associated interstitial lung disease (ILD) routinely treated with cyclophosphamide. Hsp90 was increased in SSc compared to healthy controls. Hsp90 correlated positively with C-reactive protein and negatively with pulmonary function tests: forced vital capacity and diffusing capacity for carbon monoxide (DLCO). In patients with diffuse cutaneous (dc) SSc, Hsp90 positively correlated with the modified Rodnan skin score. In SSc-ILD patients treated with cyclophosphamide, no differences in Hsp90 were found between baseline and after 1, 6, or 12 months of therapy. However, baseline Hsp90 predicts the 12-month change in DLCO. This study shows that Hsp90 plasma levels are increased in SSc patients compared to age-/sex-matched healthy controls. Elevated Hsp90 in SSc is associated with increased inflammatory activity, worse lung functions, and in dcSSc, with the extent of skin involvement. Baseline plasma Hsp90 predicts the 12-month change in DLCO in SSc-ILD patients treated with cyclophosphamide.
2,948 citations
École Polytechnique Fédérale de Lausanne1, Centre national de la recherche scientifique2, Ghent University3, French Institute of Health and Medical Research4, Centre for Addiction and Mental Health5, Blaise Pascal University6, Vrije Universiteit Brussel7, University of California, Los Angeles8, Samsung Medical Center9, University of Massachusetts Medical School10, Memorial Sloan Kettering Cancer Center11, Delft University of Technology12, Claude Bernard University Lyon 113, Joseph Fourier University14, Forschungszentrum Jülich15, University of Santiago, Chile16, Curie Institute17
TL;DR: A detailed description of the design and development of GATE is given by the OpenGATE collaboration, whose continuing objective is to improve, document and validate GATE by simulating commercially available imaging systems for PET and SPECT.
Abstract: Monte Carlo simulation is an essential tool in emission tomography that can assist in the design of new medical imaging devices, the optimization of acquisition protocols and the development or assessment of image reconstruction algorithms and correction techniques. GATE, the Geant4 Application for Tomographic Emission, encapsulates the Geant4 libraries to achieve a modular, versatile, scripted simulation toolkit adapted to the field of nuclear medicine. In particular, GATE allows the description of time-dependent phenomena such as source or detector movement, and source decay kinetics. This feature makes it possible to simulate time curves under realistic acquisition conditions and to test dynamic reconstruction algorithms. This paper gives a detailed description of the design and development of GATE by the OpenGATE collaboration, whose continuing objective is to improve, document and validate GATE by simulating commercially available imaging systems for PET and SPECT. Large effort is also invested in the ability and the flexibility to model novel detection systems or systems still under design. A public release of GATE licensed under the GNU Lesser General Public License can be downloaded at http:/www-lphe.epfl.ch/GATE/. Two benchmarks developed for PET and SPECT to test the installation of GATE and to serve as a tutorial for the users are presented. Extensive validation of the GATE simulation platform has been started, comparing simulations and measurements on commercially available acquisition systems. References to those results are listed. The future prospects towards the gridification of GATE and its extension to other domains such as dosimetry are also discussed.
1,899 citations
TL;DR: This work demonstrates simultaneous phase and amplitude extraction from a single defocused image of a homogeneous object and solves the twin‐image problem of in‐line holography and is capable of analysing data obtained using X‐ray microscope, electron microscopy, neutron microscopy or visible‐light microscopy.
Abstract: We demonstrate simultaneous phase and amplitude extraction from a single defocused image of a homogeneous object. Subject to the assumptions explicitly stated in the derivation, the algorithm solves the twin-image problem of in-line holography and is capable of analysing data obtained using X-ray microscopy, electron microscopy, neutron microscopy or visible-light microscopy, especially as they relate to defocus and point projection methods. Our simple, robust, non-iterative and computationally efficient method is applied to data obtained using an X-ray phase contrast ultramicroscope.
1,589 citations
TL;DR: In this article, the propagation of phase and irradiance are derived, and a Green's function solution for the phase in terms of irradiance and perimeter phase values is given A measurement scheme is discussed, and the results of a numerical simulation are given Both circular and slit pupils are considered.
Abstract: Equations for the propagation of phase and irradiance are derived, and a Green’s function solution for the phase in terms of irradiance and perimeter phase values is given A measurement scheme is discussed, and the results of a numerical simulation are given Both circular and slit pupils are considered An appendix discusses the local validity of the parabolic-wave equation based on the factorized Helmholtz equation approach to the Rayleigh–Sommerfeld and Fresnel diffraction theories Expressions for the diffracted-wave field in the near-field region are given
1,310 citations