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Viermetz M, Gustschin N, Schmid C, Haeusele J, Gleich B, Renger B, Koehler T, Pfeiffer F. Initial Characterization of Dark-Field CT on a Clinical Gantry. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:1035-1045. [PMID: 36395124 DOI: 10.1109/tmi.2022.3222839] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
X-ray computed tomography (CT) is an important non-destructive imaging technique, particularly in clinical diagnostics. Even with the latest innovations like dual-energy and photon-counting CT, the image contrast is solely generated from attenuation in the tissue. An extension - fully compatible with these novelties - is dark-field CT, which retrieves an additional, so-called dark-field contrast. Unlike the attenuation channel, the dark-field channel is sensitive to tissue microstructure and porosity below the resolution of the imaging system, which allows additional insights into the health of the lung tissue or the structure of calcifications. The potential clinical value has been demonstrated in several preclinical studies and recently also in radiography patient studies. Just recently the first dark-field CT for the human body was established at the Technical University of Munich and in this paper, we discuss the performance of this prototype. We evaluate the interferometer components and the imposed challenges that the integration into the CT gantry brings by comparing the results to simulations and measurements at a laboratory setup. The influence of the clinical X-ray source on the Talbot-Lau interferometer and the impact of vibrations, which are immanent on the clinical CT gantry, are analyzed in detail to reveal their characteristic frequencies and origin. A beam hardening correction is introduced as an important step to adapt to the poly-chromatic spectrum and make quantitative dark-field imaging possible. We close with an analysis of the image resolution and the applied patient dose, and conclude that the performance is sufficient to suggest initial patient studies using the presented dark-field CT system.
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2
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Pil-Ali A, Adnani S, Karim KS. Self-aligned multi-layer X-ray absorption grating using large-area fabrication methods for X-ray phase-contrast imaging. Sci Rep 2023; 13:2508. [PMID: 36781907 PMCID: PMC9925796 DOI: 10.1038/s41598-023-29580-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 02/07/2023] [Indexed: 02/15/2023] Open
Abstract
X-ray phase-contrast (XPCi) imaging methods are an emerging medical imaging approach that provide significantly better soft tissue contrast and could function as a viable extension to conventional X-ray, CT, and even some MRI. Absorption gratings play a central role in grating-based XPCi systems, especially because they enable the acquisition of three images in a single exposure: transmission, refraction, and dark-field. An impediment to commercial development and adoption of XPCi imaging systems is the lack of large area, high aspect ratio absorption gratings. Grating technology development, primarily due to technological limitations, has lagged system development and today prevents the scaling up of XPCi system into a footprint and price point acceptable to the medical market. In this work, we report on a self-aligned multi-layer grating fabrication process that can enable large-area X-ray absorption gratings with micron-scale feature sizes. We leverage large-area fabrication techniques commonly employed by the thin-film transistor (TFT) display industry. Conventional ITO-on-glass substrates are used with a patterned film of Cr/Au/Cr that serves as a self-aligned lithography mask for backside exposure. Commonly available SU-8 photoresist is patterned using the backside exposure mask followed by an electroplating step to fill the gaps in the SU-8 with X-ray attenuating material. Consequently, the electroplated patterned material acts as a self-aligned photomask for subsequent SU-8 layer patterning and so forth. The repeatability of the reported process makes it suitable for achieving higher aspect ratio structures and is advantageous over previously reported X-ray LIGA approaches. A prototype three-layer grating, with a thickness of around [Formula: see text], having a visibility of 0.28 at [Formula: see text] with a [Formula: see text] active area was fabricated on a 4-inch glass substrate and demonstrated by modifying a commercially available 3D propagation-based XPCi Microscope. The scalable and cost-effective approach to build larger area X-ray gratings reported in this work can help expedite the commercial development and adoption of previously reported Talbot-Lau, speckle-tracking, as well as coded-aperture XPCi systems for large-area clinical and industrial applications.
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Affiliation(s)
- Abdollah Pil-Ali
- Department of Electrical and Computer Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L3G1, Canada. .,Centre for Bioengineering and Biotechnology, University of Waterloo, 200 University Ave W, Waterloo, ON, N2L3G1, Canada.
| | - Sahar Adnani
- grid.46078.3d0000 0000 8644 1405Department of Electrical and Computer Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON N2L3G1 Canada ,grid.46078.3d0000 0000 8644 1405Centre for Bioengineering and Biotechnology, University of Waterloo, 200 University Ave W, Waterloo, ON N2L3G1 Canada
| | - Karim S. Karim
- grid.46078.3d0000 0000 8644 1405Department of Electrical and Computer Engineering, University of Waterloo, 200 University Ave W, Waterloo, ON N2L3G1 Canada ,grid.46078.3d0000 0000 8644 1405Centre for Bioengineering and Biotechnology, University of Waterloo, 200 University Ave W, Waterloo, ON N2L3G1 Canada
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Viermetz M, Gustschin N, Schmid C, Haeusele J, Noel PB, Proksa R, Loscher S, Koehler T, Pfeiffer F. Technical Design Considerations of a Human-Scale Talbot-Lau Interferometer for Dark-Field CT. IEEE TRANSACTIONS ON MEDICAL IMAGING 2023; 42:220-232. [PMID: 36112565 DOI: 10.1109/tmi.2022.3207579] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Computed tomography (CT) as an important clinical diagnostics method can profit from extension with dark-field imaging, as it is currently restricted to X-rays' attenuation contrast only. Dark-field imaging allows access to more tissue properties, such as micro-structural texture or porosity. The up-scaling process to clinical scale is complex because several design constraints must be considered. The two most important ones are that the finest grating is limited by current manufacturing technology to a [Formula: see text] period and that the interferometer should fit into the CT gantry with minimal modifications only. In this work we discuss why an inverse interferometer and a triangular G1 profile are advantageous and make a compact and sensitive interferometer implementation feasible. Our evaluation of the triangular grating profile reveals a deviation in the interference pattern compared to standard grating profiles, which must be considered in the subsequent data processing. An analysis of the grating orientation demonstrates that currently only a vertical layout can be combined with cylindrical bending of the gratings. We also provide an in-depth discussion, including a new simulation approach, of the impact of the extended X-ray source spot which can lead to large performance loss and present supporting experimental results. This analysis reveals a vastly increased sensitivity to geometry and grating period deviations, which must be considered early in the system design process.
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Makarova OV, Divan R, Moldovan N, Czaplewski DA, Esposito M, Endrizzi M, Tang CM, Ferrara JD, Olivo A. Freestanding high-aspect-ratio gold masks for low-energy, phase-based x-ray microscopy. NANOTECHNOLOGY 2022; 34:10.1088/1361-6528/ac9b5f. [PMID: 36260979 PMCID: PMC9662782 DOI: 10.1088/1361-6528/ac9b5f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
High-resolution, x-ray phase contrast microscopy, a key technique with promising potential in biomedical imaging and diagnostics, is based on narrow-slit high-aspect-ratio gold gratings. We present the development, fabrication details, and experimental testing of the freestanding 10μm thick gold membrane masks with an array of 0.9-1.5μm void slit apertures for a novel low-energy x-ray microscope. The overall mask size is 4 mm × 4 mm, with a grating pitch of 7.5μm, 6.0-6.6μm wide gold bars are supported by 3μm wide crosslinks at 400μm intervals. The fabrication process is based on gold electroplating into a silicon mold coated with various thin films to form a voltage barrier, plating base, and sacrificial layer, followed by the mold removal to obtain the freestanding gold membrane with void slit apertures. We discuss key aspects for the materials and processes, including gold structures homogeneity, residual stresses, and prevention of collapsing of the grid elements. We further demonstrate the possibility to obtain high-resolution, high contrast 2D images of biological samples using an incoherent, rotating anode x-ray tube.
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Affiliation(s)
- Olga V Makarova
- Creatv MicroTech Inc., Chicago IL 60612, United States of America
| | - Ralu Divan
- Center for Nanoscale Materials, Argonne National Laboratory, IL 60439, United States of America
| | - Nicolaie Moldovan
- Center for Nanoscale Materials, Argonne National Laboratory, IL 60439, United States of America
- Alcorix Co, Plainfield, IL 60544, United States of America
| | - David A Czaplewski
- Center for Nanoscale Materials, Argonne National Laboratory, IL 60439, United States of America
| | - Michela Esposito
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Marco Endrizzi
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
| | - Cha-Mei Tang
- Creatv MicroTech Inc., Potomac MD 20854, United States of America
| | - Joseph D Ferrara
- Rigaku Americas Corp, The Woodlands, TX 77371, United States of America
| | - Alessandro Olivo
- Department of Medical Physics and Biomedical Engineering, University College London, London WC1E 6BT, United Kingdom
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Single-Shot Multicontrast X-ray Imaging for In Situ Visualization of Chemical Reaction Products. J Imaging 2021; 7:jimaging7110221. [PMID: 34821852 PMCID: PMC8621068 DOI: 10.3390/jimaging7110221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/14/2021] [Accepted: 10/18/2021] [Indexed: 12/02/2022] Open
Abstract
We present the application of single-shot multicontrast X-ray imaging with an inverted Hartmann mask to the time-resolved in situ visualization of chemical reaction products. The real-time monitoring of an illustrative chemical reaction indicated the formation of the precipitate by the absorption, differential phase, and scattering contrast images obtained from a single projection. Through these contrast channels, the formation of the precipitate along the mixing line of the reagents, the border between the solid and the solution, and the presence of the scattering structures of 100–200 nm sizes were observed. The measurements were performed in a flexible and robust setup, which can be tailored to various imaging applications at different time scales.
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6
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High resolution laboratory grating-based X-ray phase-contrast CT. Sci Rep 2018; 8:15884. [PMID: 30367132 PMCID: PMC6203738 DOI: 10.1038/s41598-018-33997-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 10/03/2018] [Indexed: 12/20/2022] Open
Abstract
The conventional form of computed tomography using X-ray attenuation without any contrast agents is of limited use for the characterization of soft tissue in many fields of medical and biological studies. Grating-based phase-contrast computed tomography (gbPC-CT) is a promising alternative imaging method solving the low soft tissue contrast without the need of any contrast agent. While highly sensitive measurements are possible using conventional X-ray sources the spatial resolution does often not fulfill the requirements for specific imaging tasks, such as visualization of pathologies. The focus of this study is the increase in spatial resolution without loss of sensitivity. To overcome this limitation a super-resolution reconstruction based on sub-pixel shifts involving a deconvolution of the image data during each iteration is applied. In our study we achieve an effective pixel size of 28 μm with a conventional rotating anode tube and a photon-counting detector. We also demonstrate that the method can upgrade existing setups to measure tomographies with higher resolution. The results show the increase in resolution at high sensitivity and with the ability to make quantitative measurements. The combination of sparse sampling and statistical iterative reconstruction may be used to reduce the total measurement time. In conclusion, we present high-quality and high-resolution tomographic images of biological samples to demonstrate the experimental feasibility of super-resolution reconstruction.
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Saghamanesh S, Aghamiri SM, Kamali-Asl A, Yashiro W. Photon detection efficiency of laboratory-based x-ray phase contrast imaging techniques for mammography: a Monte Carlo study. Phys Med Biol 2017. [PMID: 28632500 DOI: 10.1088/1361-6560/aa7a92] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An important challenge in real-world biomedical applications of x-ray phase contrast imaging (XPCI) techniques is the efficient use of the photon flux generated by an incoherent and polychromatic x-ray source. This efficiency can directly influence dose and exposure time and ideally should not affect the superior contrast and sensitivity of XPCI. In this paper, we present a quantitative evaluation of the photon detection efficiency of two laboratory-based XPCI methods, grating interferometry (GI) and coded-aperture (CA). We adopt a Monte Carlo approach to simulate existing prototypes of those systems, tailored for mammography applications. Our simulations were validated by means of a simple experiment performed on a CA XPCI system. Our results show that the fraction of detected photons in the standard energy range of mammography are about 1.4% and 10% for the GI and CA techniques, respectively. The simulations indicate that the design of the optical components plays an important role in the higher efficiency of CA compared to the GI method. It is shown that the use of lower absorbing materials as the substrates for GI gratings can improve its flux efficiency by up to four times. Along similar lines, we also show that an optimized and compact configuration of GI could lead to a 3.5 times higher fraction of detected counts compared to a standard and non-optimised GI implementation.
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Affiliation(s)
- S Saghamanesh
- Department of Medical Radiation Engineering, Shahid Beheshti University, Tehran 1983969411, Iran
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Luo R, Wu Z, Xiong Y, Wei C, Zhang X, Hu R, Wang L, Guo L, Liu G, Tian Y. Optimization of grating duty cycle in non-interferometric grating-based X-ray phase contrast imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:085102. [PMID: 28863686 DOI: 10.1063/1.4996507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Grating-based X-ray phase contrast imaging technology is one of the most potential imaging methods in real applications. It can be classified into two categories: interferometry and non-interferometric imaging. The non-interferometric grating-based X-ray phase contrast imaging (NIGPCI) instrument has a great advantage in the forthcoming commercial applications for the flexible system design and the use of large periodic gratings. The performance of the NIGPCI instrument depends on its angular sensitivity to a great extent. Therefore, good angular sensitivity is mandatory in order to obtain high quality phase-contrast images. Several parameters, such as the X-ray spectrum, the inter-grating distances, and the parameters of the three gratings, influence the angular sensitivity of the imaging system. However, the quantitative relationship between the angular sensitivity and grating duty cycle is unclear. Therefore, this paper is devoted to revealing their internal relation by theoretical deduction and emulation of the imaging process with the theories of linear system and Fourier optics. Furthermore, a quantitative analysis method to optimize the duty cycles of gratings is proposed and its applicability to a general NIGPCI system is verified.
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Affiliation(s)
- Ronghui Luo
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
| | - Zhao Wu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
| | - Ying Xiong
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
| | - Chenxi Wei
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
| | - Xiaobo Zhang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
| | - Renfang Hu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
| | - Lei Wang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
| | - Liang Guo
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
| | - Gang Liu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
| | - Yangchao Tian
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, Anhui, China
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9
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Saghamanesh S, Aghamiri SMR, Olivo A, Sadeghilarijani M, Kato H, Kamali-Asl A, Yashiro W. Edge-illumination x-ray phase contrast imaging with Pt-based metallic glass masks. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:063705. [PMID: 28667949 DOI: 10.1063/1.4989700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Edge-illumination x-ray phase contrast imaging (EI XPCI) is a non-interferometric phase-sensitive method where two absorption masks are employed. These masks are fabricated through a photolithography process followed by electroplating which is challenging in terms of yield as well as time- and cost-effectiveness. We report on the first implementation of EI XPCI with Pt-based metallic glass masks fabricated by an imprinting method. The new tested alloy exhibits good characteristics including high workability beside high x-ray attenuation. The fabrication process is easy and cheap, and can produce large-size masks for high x-ray energies within minutes. Imaging experiments show a good quality phase image, which confirms the potential of these masks to make the EI XPCI technique widely available and affordable.
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Affiliation(s)
- Somayeh Saghamanesh
- Department of Medical Radiation Engineering, Shahid Beheshti University, Tehran 1983969411, Iran
| | | | - Alessandro Olivo
- Department of Medical Physics and Bioengineering, University College London, Malet Place, Gower Street, London WC1E 6BT, United Kingdom
| | - Maryam Sadeghilarijani
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai 980-8577, Japan
| | - Hidemi Kato
- Institute for Materials Research (IMR), Tohoku University, Sendai 980-8577, Japan
| | - Alireza Kamali-Asl
- Department of Medical Radiation Engineering, Shahid Beheshti University, Tehran 1983969411, Iran
| | - Wataru Yashiro
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai 980-8577, Japan
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Schröter TJ, Koch FJ, Meyer P, Kunka D, Meiser J, Willer K, Gromann L, De Marco F, Herzen J, Noel P, Yaroshenko A, Hofmann A, Pfeiffer F, Mohr J. Large field-of-view tiled grating structures for X-ray phase-contrast imaging. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:015104. [PMID: 28147659 DOI: 10.1063/1.4973632] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
X-ray grating-based interferometry promises unique new diagnostic possibilities in medical imaging and materials analysis. To transfer this method from scientific laboratories or small-animal applications to clinical radiography applications, compact setups with a large field of view (FoV) are required. Currently the FoV is limited by the grating area, which is restricted due to the complex manufacturing process. One possibility to increase the FoV is tiling individual grating tiles to create one large area grating mounted on a carrier substrate. We investigate theoretically the accuracy needed for a tiling process in all degrees of freedom by applying a simulation approach. We show how the resulting precision requirements can be met using a custom-built frame for exact positioning. Precise alignment is achieved by comparing the fringe patterns of two neighboring grating tiles in a grating interferometer. With this method, the FoV can be extended to practically any desired length in one dimension. First results of a phase-contrast scanning setup with a full FoV of 384 mm × 24 mm show the suitability of this method.
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Affiliation(s)
- Tobias J Schröter
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Frieder J Koch
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Pascal Meyer
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Danays Kunka
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Jan Meiser
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Konstantin Willer
- Chair of Biomedical Physics, Department of Physics and Institute of Medical Engineering, Technical University of Munich, 85748 Garching, Germany
| | - Lukas Gromann
- Chair of Biomedical Physics, Department of Physics and Institute of Medical Engineering, Technical University of Munich, 85748 Garching, Germany
| | - Fabio De Marco
- Chair of Biomedical Physics, Department of Physics and Institute of Medical Engineering, Technical University of Munich, 85748 Garching, Germany
| | - Julia Herzen
- Chair of Biomedical Physics, Department of Physics and Institute of Medical Engineering, Technical University of Munich, 85748 Garching, Germany
| | - Peter Noel
- Chair of Biomedical Physics, Department of Physics and Institute of Medical Engineering, Technical University of Munich, 85748 Garching, Germany
| | - Andre Yaroshenko
- Chair of Biomedical Physics, Department of Physics and Institute of Medical Engineering, Technical University of Munich, 85748 Garching, Germany
| | - Andreas Hofmann
- Institute for Applied Computer Science, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics and Institute of Medical Engineering, Technical University of Munich, 85748 Garching, Germany
| | - Jürgen Mohr
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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