Wednesday 17 July
Specifically, small-pixel (<100 µm) photon-counting detectors equipped with multiple energy thresholds and effective charge-sharing compensation mechanisms enable the acquisition of energy-binned images at high spatial resolution. By exploiting the energy dependence of the attenuation coefficient of different materials, these images are used to perform material decomposition, yielding quantitative density maps of chosen basis materials. Being based on X-ray attenuation, XSI has a limited ability to capture details featuring a poor attenuation contrast (i.e., low-Z materials).
This limitation can be overcome by XPCI. Except for propagation-based imaging, all laboratory XPCI techniques make use of some X-ray wavefront marker or modulator. Both attenuation and (differential) phase signals are extracted based on the modification of the detected modulation pattern induced by the sample. Regardless of the employed technique, attenuation and (integrated) phase can be used, similarly to energy-binned images, as input to material decomposition algorithms. This approach is particularly suited for soft tissues and light materials, while it can be outperformed by XSI when dealing with high-Z materials with distinctive attenuation features (e.g., K-edges of contrast media).
In this context, a joint use of spectral and phase-contrast imaging can offer quantification and visibility of both high-Z and low-Z materials. In this talk, one example of the implementation of both XSI and XPCI within a new compact multimodal X-ray imaging will be presented. The system is based on a spectral detector with a 62 µm pixel size and it integrates the edge-illumination technique. Spectral, phase-contrast, and spectral-phase contrast images of biological samples will be presented, along with demonstrations of material decomposition techniques and de-noising algorithms. The limitations of the current approach and potential future advancements will be discussed.
While high-quality images are important, other relevant factors such as accessibility, fast data reconstruction, and image interpretation, are crucial for bio-medical impact. Synchrotron based x-ray imaging offers superior image quality, but laboratory based set-ups at the hospital provides a different level of accessibility. For some studies, both synchrotron and laboratory based imaging systems are needed.
In this talk I will present the hardware solutions we have at the experimental x-ray imaging lab at Lund University, Medical Radiation Physics, and give examples applications.
There is now a strong case to fully develop plasma based accelerators as dedicated x-ray machines. The combination of source properties will deliver an exceptional capability for rapid, blur-free scanning at high spatial and temporal resolution. A broad range of applications is envisaged, from clinical imaging to non-destructive inspection of additively manufactured automotive and aerospace components.
The CLF is constructing a new facility, the Extreme Photonics Applications Centre (EPAC), that will employ diode-pumped laser technology to produce a high repetition rate (10 Hz) petawatt laser system. Through laser-plasma acceleration this will create a versatile x-ray capability for scientific and industrial applications. I will describe our facility design and operational philosophy, and discuss the potential for wider deployment of this technology.
This will be illustrated by first results and future plans related to the new KIT experimental stations LAMINO-II and UFO-II, currently under development at the superconducting wiggler beamline IMAGE at the KIT Light Source, and KIT´s new HIKA station for hierarchical imaging and serial tomography at the P23 undulator beamline at PETRA III, DESY. The talk shows their methodical capabilities and gives application examples of small animal studies, in particular, (1) dose-efficient micrometer-resolved imaging close to the theoretical limit by using coherent asymmetric crystal optics, enabling, e.g., unprecedented in vivo behavioral studies of parasitoid insects within their hosts, (2) drastic contrast enhancement for low resolution propagation-based imaging of soft tissues by realizing kilometer-long propagation distances, (3) hierarchical 3D imaging by 3D screening of large areas and zooming into selected regions of interest using computed laminography guided by on-the-fly data processing, e.g., for paleontological studies of compression fossils, (4) large comparative 3D morphological studies of thousands of specimen, such as insects or vertebrate model organisms for correlation with genetic and environmental meta data.
Random phase modulation techniques were developed in 2012 at synchrotrons, using the "speckle phenomenon" to create a random intensity pattern which modifications upon introduction of the sample would give its phase and scattering information. Since then, we developed further the technique and we do not use any more speckles to create the necessary modulations. Thanks to different patents on the membranes, the technique is now successfully transferred to lab settings and it has now become a commercial product.
In this talk, we will introduce the concepts, the optimization of the membranes, and the associated phase retrieval techniques to produce phase contrast and dark-field images with modulation based imaging.
In this talk, the conventional EI X-ray imaging protocol is revisited and recent efforts to increase flexibility in both acquisition and multi-contrast image reconstruction are discussed.
10:30 – 10:40
Opening
Opening
Welcome to the Workshop
Silvia Cipiccia
Silvia is a lecturer in Advanced X-ray Imaging at the Department of Medical Physics and Biomedical Engineering at the University College London. Silvia is an expert in x-ray imaging, especially on coherent diffraction imaging and on novel schemes of compact light sources, namely laser-plasma driven radiation sources. Her work aims to pushing the boundaries of x-ray quantitative phase imaging, in particular x-ray ptychography, in terms of information content and acquisition modalities. Her recent work focuses on translating x-ray imaging techniques born at synchrotron facilities to compact light sources, from standard x-ray tubes to more innovative technologies such as inverse-Compton and laser-plasma sources; in all these cases, she adapts the imaging techniques to the unique properties of the sources. As part of this, in her recent works, Silvia pioneered the lab translation of far-field x-ray ptychography and has proven simultaneous phase and dark field imaging are possible at the femtosecond using laser-driven x-ray sources.
Marco Endrizzi
Marco Endrizzi is Professor of Experimental Physics at the Department of Medical Physics and Biomedical Engineering, University College London. He is part of the Advanced X-ray Imaging group, where X-ray phase-contrast imaging (XPCI) techniques have been pioneered and developed for nearly two decades. His contributions include a method for X-ray dark-field imaging under incoherent illumination, hence suitable for laboratory settings as it is compatible with standard X-ray tubes. Marco is co-Director of the National Research Facility for lab-based X-ray Computed Tomography (NXCT, https://nxct.ac.uk/), which makes the first lab-XPCI systems openly available to industry and the research community, and leads the X-ray Microscopy and Tomography lab at the The Francis Crick Institute (https://www.crick.ac.uk/research/labs/marco-endrizzi).
Charlie Wood
Charlie is the X-ray facility manager within the Future Technology Centre at the University of Portsmouth. His research focuses on lab-based X-ray technique and technology development. As the founder of the Correlative Multimodal Microscopy (CoMic) Network he explores multidimensional workflows that span several modalities at different length scales. Charlie’s background is in pure mathematics and physics. He completed his PhD in nuclear fusion (liquid metal magnetohydrodynamics) at Queen Mary University of London. It wasn’t until his first postdoctoral position at the University of Southampton that Charlie began working with X-rays. Moving about different postdoctoral positions, Charlie collected knowledge on various characterisation techniques involving lasers and electrons, before moving to Imperial College to research the link between material microstructure and macroscopic performance for batteries and fuel cell electrodes. During this time Charlie managed an X-ray lab within the Royal School of Mines, and it was here that he started to explore correlative methods using X-ray imaging and volume electron microscopy (vEM). Charlie has been the co-chair of the Royal Microscopical Society X-ray group since Jan 2021, and has recently started the vEM CoMic X-ray Group, of which he is chair.
10:40 – 11:10
Spectral and phase-contrast imaging with a compact multimodal imaging system
Spectral and phase-contrast imaging with a compact multimodal imaging system
Luca Brombal
Owing to the advent of energy-sensitive detectors and phase-sensitive techniques with reduced coherence requirements, both X-ray spectral imaging (XSI) and X-ray phase-contrast imaging (XPCI) are now viable options for compact laboratory setups.Specifically, small-pixel (<100 µm) photon-counting detectors equipped with multiple energy thresholds and effective charge-sharing compensation mechanisms enable the acquisition of energy-binned images at high spatial resolution. By exploiting the energy dependence of the attenuation coefficient of different materials, these images are used to perform material decomposition, yielding quantitative density maps of chosen basis materials. Being based on X-ray attenuation, XSI has a limited ability to capture details featuring a poor attenuation contrast (i.e., low-Z materials).
This limitation can be overcome by XPCI. Except for propagation-based imaging, all laboratory XPCI techniques make use of some X-ray wavefront marker or modulator. Both attenuation and (differential) phase signals are extracted based on the modification of the detected modulation pattern induced by the sample. Regardless of the employed technique, attenuation and (integrated) phase can be used, similarly to energy-binned images, as input to material decomposition algorithms. This approach is particularly suited for soft tissues and light materials, while it can be outperformed by XSI when dealing with high-Z materials with distinctive attenuation features (e.g., K-edges of contrast media).
In this context, a joint use of spectral and phase-contrast imaging can offer quantification and visibility of both high-Z and low-Z materials. In this talk, one example of the implementation of both XSI and XPCI within a new compact multimodal X-ray imaging will be presented. The system is based on a spectral detector with a 62 µm pixel size and it integrates the edge-illumination technique. Spectral, phase-contrast, and spectral-phase contrast images of biological samples will be presented, along with demonstrations of material decomposition techniques and de-noising algorithms. The limitations of the current approach and potential future advancements will be discussed.
Speakers
Luca Brombal
11:10 – 11:30
Speckle-based imaging (SBI) is an X-ray phase-contrast imaging
Speckle-based imaging (SBI) is an X-ray phase-contrast imaging
Vittorio di Trapani
Speckle-based imaging (SBI) is an X-ray phase-contrast imaging (XPCI) technique that provides access to phase and small-angle-scattering (or dark-field) signals, in addition to the attenuation signal achieved with conventional approaches. To retrieve the phase and dark-field signals, SBI uses random wavefront markers, such as simple sandpapers, to generate speckles at the detector. As for other XPCI techniques, SBI was first pioneered using synchrotron radiation. When translating the technique from synchrotron sources to compact laboratory setups, the reduced coherence of the source and limitations in the available resolution yield lower speckle visibility, thus hampering the retrieval of the phase and dark-field signals. Here, we present a newly established OPTimal IMAging and TOmography (OPTIMATO) laboratory for X-ray imaging hosted at the Elettra synchrotron (Trieste, Italy). The presented setup includes a micro-focus high-brilliance liquid-metal jet source that emits X-rays on two opposite sides. Two semi-independent branches featuring maximum source-detector distances of 2m and 4m have been implemented. The short branch is devoted to high-resolution imaging with resolutions below 1μm, whereas the long branch is mainly dedicated to SBI with resolutions up to 15μm. Summarizing the main limiting factors when moving SBI applications from synchrotron facilities to compact laboratory setups, we present the challenges in the design of the laboratory setup and the first SBI images obtained at the OPTIMATO laboratory.Speakers
Vittorio di Trapani
11:30 – 11:50
The Ghent University Centre for X-ray Tomography
The Ghent University Centre for X-ray Tomography
Matthieu Boone
The Ghent University Centre for X-ray Tomography (UGCT) is a multidisciplinary research consortium and core facility, hosting several unique custom-built µCT scanners. These systems offer the flexibility needed for experiments with novel acquisition schemes and instrumentation. In this talk, an overview will be given of the capabilities of these different systems.Speakers
Matthieu Boone
11:50 – 12:10
Simultaneous x-ray dark-field and attenuation contrast retrieval for single-shot laboratory-based tomography
12:10 – 12:30
Towards clinically relevant applications of virtual histology
Towards clinically relevant applications of virtual histology
Martin Bech
Development of various phase-contrast x-ray imaging methods have let to a vast improvement of soft tissue imaging, and opened for the possibility of so-called virtual histology: Microscopic analysis of tissue biopsies in three dimensions. With the aim to step closer to clinically relavant applications, we have installed a laboratory for experimental x-ray imaging at the premises of Lund University Hospital.While high-quality images are important, other relevant factors such as accessibility, fast data reconstruction, and image interpretation, are crucial for bio-medical impact. Synchrotron based x-ray imaging offers superior image quality, but laboratory based set-ups at the hospital provides a different level of accessibility. For some studies, both synchrotron and laboratory based imaging systems are needed.
In this talk I will present the hardware solutions we have at the experimental x-ray imaging lab at Lund University, Medical Radiation Physics, and give examples applications.
Speakers
Martin Bech
12:30 – 12:50
Lab based micro and nano-tomography of plants and human tissue
Lab based micro and nano-tomography of plants and human tissue
Rajmund Mokso
The 3D imaging center at the Technical University of Denmark is a competence center for X-ray and neutron imaging. It is home to a national facility, DANFIX: a 900 m2 laboratory with room for 10 CT scanners. The facility is used for research and education within a broad range of natural, technical and health disciplines. Our development of phase contrast imaging at its applications to life science relies mainly on two liquid metal-jet based systems. One commercial uCT scanner and one self built nano-scale scanner. This is a zone plate based microscope operating in Zernike phase contrast mode with a single photon counting detector being the important component in the endeavor to build an exceptionally dose efficient scanner. In my talk I will introduce our approach to lab based phase contrast tomography. I will also cover two specific scientific cases. The first being in vivo imaging of plant leaves, the second is 3D histology of human tissue with potential clinical diagnostic value.Speakers
Rajmund Mokso
13:30 – 13:50
The ALLS Betatron X-ray beamline : toward a stable and high brightness laboratory source
The ALLS Betatron X-ray beamline : toward a stable and high brightness laboratory source
Sylvain Fourmaux
The ALLS Laser Wakefield Acceleration beamline is produced by using INRS high-power laser system that allows 145 TW (3.2 J, 22 fs) on target at 2.5 Hz repetition rate. It can typically be used to accelerate electrons up to 400 MeV by focusing the laser into a gas jet. The synchrotron radiation emitted during the acceleration process have a critical energy between 15-25 keV. The resulting X-ray source size is ~ 1 µm with a femtosecond pulse duration. The beamline is being optimized to deliver a stable and homogeneous X-ray beam suitable for imaging applications like phase contrast imaging. Currently the emphasis is made on improving the number of produced photons.Speakers
Sylvain Fourmaux
13:45 – 14:45
EPAC: A new UK high power laser facility for applications
EPAC: A new UK high power laser facility for applications
Dan Symes
High power lasers (>100 TW) can be used as the driver for compact light sources with unique properties that are ideal for advanced imaging applications. The laser is used to create a cm-scale plasma accelerator producing femtosecond x-ray pulses with a micron-scale source size and exceptionally high brightness. X-ray emission is tunable from the few keV range up to 100s keV, suitable for phase contrast imaging of soft tissue, polymers and composites as well as denser materials. I will present examples of proof of concept imaging obtained with the Gemini Ti:Sapphire laser at the Central Laser Facility.There is now a strong case to fully develop plasma based accelerators as dedicated x-ray machines. The combination of source properties will deliver an exceptional capability for rapid, blur-free scanning at high spatial and temporal resolution. A broad range of applications is envisaged, from clinical imaging to non-destructive inspection of additively manufactured automotive and aerospace components.
The CLF is constructing a new facility, the Extreme Photonics Applications Centre (EPAC), that will employ diode-pumped laser technology to produce a high repetition rate (10 Hz) petawatt laser system. Through laser-plasma acceleration this will create a versatile x-ray capability for scientific and industrial applications. I will describe our facility design and operational philosophy, and discuss the potential for wider deployment of this technology.
Speakers
Daniel Symes
14:10 – 14:30
Ultrafast X-ray sources driven by femtosecond lasers at the Extreme Light Infrastructure (ELI) Beamlines facility
Ultrafast X-ray sources driven by femtosecond lasers at the Extreme Light Infrastructure (ELI) Beamlines facility
Uddhab Chaulagain
ELI Beamlines, one of the pillars of the European Extreme Light Infrastructure project (ELI), is a high-power laser facility. The facility hosts several state-of-the-art, high-power laser systems ranging from a few Terawatt (PW) peak power to 10 PW (Petawatt) peak power. The main objective of the facility is to provide beams of ultrashort particles and photons sources to the user community from various fields of research. In this contribution I will introduce the ELI beamlines project, summarize the current status of research and implementation of three types of X-ray sources: the HHG Beamline [1], the plasma X-ray source, the Gammatron beamline based on laser-plasma accelerator (LPA) [2], and a Betatron source dedicated to plasma physics research. X-ray pulse sources driven by high peak power kHz femtosecond lasers such as high-order harmonic sources and plasma X-ray sources have been commissioned and already entered the operation phase. The second LPA-based hard X-ray Betatron X-ray is being developed in the ELI plasma physics platform (P3) [3] located at the experimental hall E3. It aims to serve as a backlighter for advanced laser-matter interaction experiments such as high-energy-density physics, intense laser-matter interaction, and advanced plasma physics experiments combined with multiple laser beams [4]. Besides, I will present an advanced scheme for the enhancement of hard X-ray photon flux by using the density-tailored plasma to control relativistic electron orbits [5] and nonlinear resonances due to interaction with a two-color laser field [6].
References
1. O. Hort, et al. "High-flux source of coherent XUV pulses for user applications." Optics express 27.6 (2019): 8871-8883.
2. U. Chaulagain, et al. "ELI Gammatron Beamline: A Dawn of Ultrafast Hard X-ray Science." Photonics. Vol. 9. No. 11., 2022.
3. S. Weber, et al. "P3: An installation for high-energy density plasma physics and ultra-high intensity laser–matter interaction at ELI-Beamlines." Matter and Radiation at Extremes 2.4 (2017): 149-176.
4. N. Jourdain, et al. "The L4n laser beamline of the P3-installation: Towards high-repetition rate high-energy density physics at ELI-Beamlines." MRE 6.1 (2021): 015401.
5. M. Kozlova, et al. "Hard X rays from laser-wakefield accelerators in density tailored plasmas." Physical Review X 10.1 (2020): 011061.
6. M. Lamač et al., “Two-color nonlinear resonances in betatron oscillations of laser accelerated relativistic electrons”, PRR, 3(3), p.033088 (2021).
Speakers
Uddhab Chaulagain
14:30 – 14:50
Challenges and Perspectives of in toto and in vivo Small Animal Imaging with Synchrotron Radiation
Challenges and Perspectives of in toto and in vivo Small Animal Imaging with Synchrotron Radiation
Tilo Bamubach
The talk will discuss recent results and perspectives for synchrotron based 2D/3D/4D full-field hard X-ray imaging techniques at KIT with a special focus on challenges of in toto up to in vivo small animal imaging with synchrotron radiation. In particular, current developments, new approaches and further challenges towards (I) dose-efficient propagation-based phase-contrast imaging, (II) hierarchical imaging of large, flat samples and (III) serial computed microtomography will be outlined.This will be illustrated by first results and future plans related to the new KIT experimental stations LAMINO-II and UFO-II, currently under development at the superconducting wiggler beamline IMAGE at the KIT Light Source, and KIT´s new HIKA station for hierarchical imaging and serial tomography at the P23 undulator beamline at PETRA III, DESY. The talk shows their methodical capabilities and gives application examples of small animal studies, in particular, (1) dose-efficient micrometer-resolved imaging close to the theoretical limit by using coherent asymmetric crystal optics, enabling, e.g., unprecedented in vivo behavioral studies of parasitoid insects within their hosts, (2) drastic contrast enhancement for low resolution propagation-based imaging of soft tissues by realizing kilometer-long propagation distances, (3) hierarchical 3D imaging by 3D screening of large areas and zooming into selected regions of interest using computed laminography guided by on-the-fly data processing, e.g., for paleontological studies of compression fossils, (4) large comparative 3D morphological studies of thousands of specimen, such as insects or vertebrate model organisms for correlation with genetic and environmental meta data.
Speakers
Tilo Baumbach
14:50 – 15:10
Quantitative X-ray imaging – towards material-specific numbers from images
Quantitative X-ray imaging – towards material-specific numbers from images
Julia Herzen
Multimodal and spectral imaging with conventional laboratory X-ray sources has become widely available in the last decade. The innovations that have made this possible are various phase-contrast techniques, novel X-ray sources and photon-counting, energy-resolving X-ray detectors. By combining complementary multimodal information about the objects under investigation, we can identify and quantify materials in 3D datasets at reduced noise levels (Braig et al., 2020), or even provide numbers on the structural sizes of porosity in bulk samples without directly resolving the structures (Sellerer et al., 2021; Taphorn et al., 2021, 2023). Here, we will review the potential of this quantitative imaging methods by highlighting the recent results on biomedical applications.
Braig, E. M., Pfeiffer, D., Willner, M., Sellerer, T., Taphorn, K., Petrich, C., Scholz, J., Petzold, L., Birnbacher, L., Dierolf, M., Pfeiffer, F., & Herzen, J. (2020). Single spectrum three-material decomposition with grating-based X-ray phase-contrast CT. Physics in Medicine and Biology, 65(18), 185011. https://doi.org/10.1088/1361-6560/ab9704
Sellerer, T., Mechlem, K., Tang, R., Taphorn, K. A., Pfeiffer, F., & Herzen, J. (2021). Dual-Energy X-Ray Dark-Field Material Decomposition. IEEE Transactions on Medical Imaging, 40(3), 974–985. https://doi.org/10.1109/TMI.2020.3043303
Taphorn, K., Kaster, L., Sellerer, T., Hötger, A., & Herzen, J. (2023). Spectral X-ray dark-field signal characterization from dual-energy projection phase-stepping data with a Talbot-Lau interferometer. Scientific Reports, 13(1), 767. https://doi.org/10.1038/s41598-022-27155-1
Taphorn, K., Mechlem, K., Sellerer, T., De Marco, F., Viermetz, M., Pfeiffer, F., Pfeiffer, D., & Herzen, J. (2021). Direct Differentiation of Pathological Changes in the Human Lung Parenchyma with Grating-Based Spectral X-ray Dark-Field Radiography. IEEE Transactions on Medical Imaging, 40(6), 1568–1578. https://doi.org/10.1109/TMI.2021.3061253
Speakers
Julia Herzen
15:10 – 15:30
Propagation-based approaches to dark-field x-ray imaging
Propagation-based approaches to dark-field x-ray imaging
Kaye Morgan
One of the simplest experimental approaches to phase-contrast x-ray imaging is a propagation-based set-up, where the x-ray wavefield self-interferes during propagation over some distance from a sample to a detector. Unlike other phase-contrast imaging set-ups, propagation-based set-ups have not been able to capture a dark-field image until recently. In the last year, we have demonstrated two possible propagation-based approaches to dark-field imaging. These approaches are based on our proposed 'X-ray Fokker-Planck Equation', which describes how both phase and dark-field effects emerge during the propagation of an x-ray wavefield. Using this equation as a model, propagation-based images from either a) two energies or b) two sample-to-detector distances can be used to extract sample thickness and dark-field images. We hope that these developments can inspire new approaches to phase and dark-field imaging that can be easily realised in laboratories, hospitals, and more broadly.Speakers
Kaye Morgan
16:00 – 16:20
High-resolution phase-contrast laboratory bioimaging
High-resolution phase-contrast laboratory bioimaging
Hans Hertz
High-spatial-resolution propagation-based phase-contrast x-ray imaging requires a small-spot high-flux source. We pioneered the liquid-metal-jet microfocus source which, in its present commercial implementation, provides a 5-25 µm x-ray spot with up to 1 kW e-beam power (Excillum AB). This source enables several biomedical phase-contrast imaging applications where high spatial resolution, high contrast and short exposure time are critical. Examples: Cellular-resolution imaging for virtual x-ray histology as well as for clinical resection margin assessment, potentially with rapid intraoperative feedback. Preclinical in-vivo small-animal lung imaging, where exposure times must be short due to the respiratory movement. Furthermore, we will provide an outlook towards clinical phase-contrast medical imaging based on two computational studies. Finally, and if time permits, our efforts on X-ray fluorescence imaging for high-resolution detection of tumors in live mice are discussed.
Speakers
Hans Hertz
16:20 – 16:40
From Speckle at the synchrotron to modulation-based imaging using conventional sources: a simple method to transfer phase-contrast and dark-field imaging
From Speckle at the synchrotron to modulation-based imaging using conventional sources: a simple method to transfer phase-contrast and dark-field imaging
Emmanuel Brun
Over the last three decades, X-ray PC and Dark-field Imaging have been proposed to overcome the limitations of conventional absorption-based Imaging: their extremely high sensitivity (up to three orders of magnitude higher than absorption-based imaging) and their capability to obtain high-resolution images for a wide range of applications including breast, osteoarticular, brain and lung imaging is reported in many studies.Random phase modulation techniques were developed in 2012 at synchrotrons, using the "speckle phenomenon" to create a random intensity pattern which modifications upon introduction of the sample would give its phase and scattering information. Since then, we developed further the technique and we do not use any more speckles to create the necessary modulations. Thanks to different patents on the membranes, the technique is now successfully transferred to lab settings and it has now become a commercial product.
In this talk, we will introduce the concepts, the optimization of the membranes, and the associated phase retrieval techniques to produce phase contrast and dark-field images with modulation based imaging.
Speakers
Emmanuel Brun
16:40 – 17:00
High content volumetric histology with subcellular resolution using a laboratory-based x-ray microscope.
High content volumetric histology with subcellular resolution using a laboratory-based x-ray microscope.
Michela Esposito
Volumetric imaging of mm-sized soft tissue samples with micron resolution opens new possibilities both in clinical and research settings, driven by the growing need for studying micro and nano scale structures in a three-dimensional context at the mesoscale. To answer these needs, we developed a laboratory-based x-ray microscope for volumetric imaging of soft tissue samples using intensity modulation masks.
In this talk we will report the first proof of concept for three-dimensional soft tissue imaging with a laboratory-based x-ray microscope based on intensity-modulation masks, allowing for multi-modal retrieval of transmission, refraction, and scattering. The newly developed microscope offers micron resolution in the resolved channels (transmission and refraction), while it can reach the nanoscale in the scattering channel. The combination of micron-level spatial resolution, set by the use of intensity modulation masks, and the enhanced contrast, arising from phase-based imaging, allows for sub-cellular in liver tissue. We will also discuss how the scattering signal correlates with nanoscale structures found in tissue, namely cellular nuclei and extra-cellular matrix.
Speakers
Michela Esposito
17:00 – 17:20
3d virtual histology with advanced laboratory radiation: from instrumentation and phase retrieval to biomedical application
3d virtual histology with advanced laboratory radiation: from instrumentation and phase retrieval to biomedical application
Tim Salditt
In order to unravel physiological and pathological mechanisms at the cellular level, structure and processes have to be visualized on a wide range of scales. Imaging at cellular and sub-cellular resolution is the realm of histology. For this purpose, the tissue obtained by surgical intervention or from a post mortem autopsy is cut into thin sections, stained and observed in an optical microscope. In conventional histology, images are obtained only of two-dimensional sections but not of the entire three-dimensional (3D) volume. In order to visualise and to quantify the cytoarchitecture in 3D, even deep in the tissue or organ, we use phase-contrast X-ray computerized tomography , as a tool for quantitative and fully digital 3D virtual histology [1]. We have partially translated the method using optimized phase retrieval [2,3], from highly coherent synchrotron to inhouse micro-focus sources. In a multi-scale approach, we cover a wide range of scales. Since the workflow is non-destructive and fully compatible with standard clinical pathology, we can perform correlative histology studies.
In this talk we discuss instrumentation at µ-focus tomography setups, image formation and advanced phase retrieval of propagation and inline holography data, the respective resolution limits, object constraints, as well as morphometric image analysis. We show how solutions and algorithms of mathematics of inverse problems and machine learning [2-4] help us to meet the challenges of phase retrieval, tomographic reconstruction, segmentation, and more generally image processing of bulky data. All to the benefit of ambitious imaging projects such as mapping the human brain [4,6] of fighting infectious diseases [6].
References:
[1] T. Salditt, A. Egner and R. D. Luke (Eds.)
Nanoscale Photonic Imaging
Springer Nature (2020), TAP, 134, Open Access Book
[2] L. M. Lohse, A.-L. Robisch, M. Töpperwien, S. Maretzke, M. Krenkel, J. Hagemann and T. Salditt
A phase-retrieval toolbox for X-ray holography and tomography
Journal of Synchrotron Radiation (2020), 27, 3
[3] S. Huhn, L.M. Lohse, J. Lucht, T. Salditt
Fast algorithms for nonlinear and constrained phase retrieval in near-field X-ray holography based on Tikhonov regularization - arXiv preprint arXiv:2205.01099 (2022)
[4] M. Eckermann, B. Schmitzer, F. van der Meer, J. Franz, O. Hansen, C. Stadelmann and T. Salditt
Three-dimensional virtual histology of the human hippocampus based on phase-contrast computed tomography
Proc. Natl. Acad. Sci. (2021), 118, 48, e2113835118
[5] M. Eckermann, J. Frohn, M. Reichardt, M. Osterhoff, M. Sprung, F. Westermeier, A.Tzankov, C. Werlein, M. Kuehnel, D. Jonigk and T. Salditt
3d Virtual Patho-Histology of Lung Tissue from Covid-19 Patients based on Phase Contrast X-ray Tomography
eLife (2020), 9:e60408
[6] M. Reichardt, P.M. Jensen, V.A. Dahl, A.B. Dahl, M. Ackermann, H. Shah, F. Länger, C. Werlein, M.P. Kuehnel, D. Jonigk and T. Salditt
3D virtual histopathology of cardiac tissue from Covid-19 patients based on phase-contrast X-ray tomography
eLife (2021), 10:e71359
Speakers
Tim Salditt
17:20 – 17:40
Flexible Edge illumination based imaging
Flexible Edge illumination based imaging
Jan Sijbers
Edge illumination (EI) is an X-ray imaging technique that, in addition to conventional absorption contrast, provides refraction and scatter contrast. It relies on an absorption mask in front of the sample that splits the X-ray beam into beamlets, which hits a second absorption mask positioned in front of the detector. The sample mask is then shifted in multiple steps with respect to the detector mask, thereby measuring an illumination curve per detector element. From the width, position, and area of this curve the absorption, refraction, and scatter contrast is then estimated.In this talk, the conventional EI X-ray imaging protocol is revisited and recent efforts to increase flexibility in both acquisition and multi-contrast image reconstruction are discussed.
Speakers
Jan Sijbers
17:40 – 18:00
Closing remarks
Closing remarks
General
Silvia Cipiccia
Silvia is a lecturer in Advanced X-ray Imaging at the Department of Medical Physics and Biomedical Engineering at the University College London. Silvia is an expert in x-ray imaging, especially on coherent diffraction imaging and on novel schemes of compact light sources, namely laser-plasma driven radiation sources. Her work aims to pushing the boundaries of x-ray quantitative phase imaging, in particular x-ray ptychography, in terms of information content and acquisition modalities. Her recent work focuses on translating x-ray imaging techniques born at synchrotron facilities to compact light sources, from standard x-ray tubes to more innovative technologies such as inverse-Compton and laser-plasma sources; in all these cases, she adapts the imaging techniques to the unique properties of the sources. As part of this, in her recent works, Silvia pioneered the lab translation of far-field x-ray ptychography and has proven simultaneous phase and dark field imaging are possible at the femtosecond using laser-driven x-ray sources.
Marco Endrizzi
Marco Endrizzi is Professor of Experimental Physics at the Department of Medical Physics and Biomedical Engineering, University College London. He is part of the Advanced X-ray Imaging group, where X-ray phase-contrast imaging (XPCI) techniques have been pioneered and developed for nearly two decades. His contributions include a method for X-ray dark-field imaging under incoherent illumination, hence suitable for laboratory settings as it is compatible with standard X-ray tubes. Marco is co-Director of the National Research Facility for lab-based X-ray Computed Tomography (NXCT, https://nxct.ac.uk/), which makes the first lab-XPCI systems openly available to industry and the research community, and leads the X-ray Microscopy and Tomography lab at the The Francis Crick Institute (https://www.crick.ac.uk/research/labs/marco-endrizzi).
Charlie Wood
Charlie is the X-ray facility manager within the Future Technology Centre at the University of Portsmouth. His research focuses on lab-based X-ray technique and technology development. As the founder of the Correlative Multimodal Microscopy (CoMic) Network he explores multidimensional workflows that span several modalities at different length scales. Charlie’s background is in pure mathematics and physics. He completed his PhD in nuclear fusion (liquid metal magnetohydrodynamics) at Queen Mary University of London. It wasn’t until his first postdoctoral position at the University of Southampton that Charlie began working with X-rays. Moving about different postdoctoral positions, Charlie collected knowledge on various characterisation techniques involving lasers and electrons, before moving to Imperial College to research the link between material microstructure and macroscopic performance for batteries and fuel cell electrodes. During this time Charlie managed an X-ray lab within the Royal School of Mines, and it was here that he started to explore correlative methods using X-ray imaging and volume electron microscopy (vEM). Charlie has been the co-chair of the Royal Microscopical Society X-ray group since Jan 2021, and has recently started the vEM CoMic X-ray Group, of which he is chair.
