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Kumschier T, Thalhammer J, Schmid C, Haeusele J, Koehler T, Pfeiffer F, Lasser T, Schaff F. Streak artefact removal in x-ray dark-field computed tomography using a convolutional neural network. Med Phys 2024. [PMID: 39012833 DOI: 10.1002/mp.17305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 06/24/2024] [Accepted: 07/01/2024] [Indexed: 07/18/2024] Open
Abstract
BACKGROUND Computed tomography (CT) relies on the attenuation of x-rays, and is, hence, of limited use for weakly attenuating organs of the body, such as the lung. X-ray dark-field (DF) imaging is a recently developed technology that utilizes x-ray optical gratings to enable small-angle scattering as an alternative contrast mechanism. The DF signal provides structural information about the micromorphology of an object, complementary to the conventional attenuation signal. A first human-scale x-ray DF CT has been developed by our group. Despite specialized processing algorithms, reconstructed images remain affected by streaking artifacts, which often hinder image interpretation. In recent years, convolutional neural networks have gained popularity in the field of CT reconstruction, amongst others for streak artefact removal. PURPOSE Reducing streak artifacts is essential for the optimization of image quality in DF CT, and artefact free images are a prerequisite for potential future clinical application. The purpose of this paper is to demonstrate the feasibility of CNN post-processing for artefact reduction in x-ray DF CT and how multi-rotation scans can serve as a pathway for training data. METHODS We employed a supervised deep-learning approach using a three-dimensional dual-frame UNet in order to remove streak artifacts. Required training data were obtained from the experimental x-ray DF CT prototype at our institute. Two different operating modes were used to generate input and corresponding ground truth data sets. Clinically relevant scans at dose-compatible radiation levels were used as input data, and extended scans with substantially fewer artifacts were used as ground truth data. The latter is neither dose-, nor time-compatible and, therefore, unfeasible for clinical imaging of patients. RESULTS The trained CNN was able to greatly reduce streak artifacts in DF CT images. The network was tested against images with entirely different, previously unseen image characteristics. In all cases, CNN processing substantially increased the image quality, which was quantitatively confirmed by increased image quality metrics. Fine details are preserved during processing, despite the output images appearing smoother than the ground truth images. CONCLUSIONS Our results showcase the potential of a neural network to reduce streak artifacts in x-ray DF CT. The image quality is successfully enhanced in dose-compatible x-ray DF CT, which plays an essential role for the adoption of x-ray DF CT into modern clinical radiology.
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Affiliation(s)
- Tom Kumschier
- Chair of Biomedical Physics, Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Garching, Germany
| | - Johannes Thalhammer
- Chair of Biomedical Physics, Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Garching, Germany
- Institute for Advanced Study, Technical University of Munich, Garching, Germany
| | - Clemens Schmid
- Chair of Biomedical Physics, Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Garching, Germany
| | - Jakob Haeusele
- Chair of Biomedical Physics, Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Garching, Germany
| | - Thomas Koehler
- Institute for Advanced Study, Technical University of Munich, Garching, Germany
- Philips Research, Hamburg, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Garching, Germany
- Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Tobias Lasser
- Munich School of BioEngineering, Technical University of Munich, Garching, Germany
- Computational Imaging and Inverse Problems, Department of Computer Science, School of Computation, Information and Technology, Technical University of Munich, Garching, Germany
| | - Florian Schaff
- Chair of Biomedical Physics, Department of Physics, School of Natural Sciences, Technical University of Munich, Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Garching, Germany
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Felchle H, Brunner V, Groll T, Walther CN, Nefzger SM, Zaurito AE, Silva MG, Gissibl J, Topping GJ, Lansink Rotgerink L, Saur D, Steiger K, Combs SE, Tschurtschenthaler M, Fischer JC. Novel Tumor Organoid-Based Mouse Model to Study Image Guided Radiation Therapy of Rectal Cancer After Noninvasive and Precise Endoscopic Implantation. Int J Radiat Oncol Biol Phys 2024; 118:1094-1104. [PMID: 37875245 DOI: 10.1016/j.ijrobp.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 10/08/2023] [Indexed: 10/26/2023]
Abstract
PURPOSE Preoperative (neoadjuvant) radiation therapy (RT) is an essential part of multimodal rectal cancer therapy. Recently, total neoadjuvant therapy (TNT), which combines simultaneous radiochemotherapy with additional courses of chemotherapy, has emerged as an effective approach. TNT achieves a pathologic complete remission in approximately 30% of resected patients, opening avenues for treatment strategies that avoid radical organ resection. Furthermore, recent studies have demonstrated that anti-programmed cell death protein 1 immunotherapy can induce clinical complete responses in patients with specific genetic alterations. There is significant potential to enhance outcomes through intensifying, personalizing, and de-escalating treatment approaches. However, the heterogeneous response rates to RT or TNT and strategies to sensitize patients without specific genetic changes to immunotherapy remain poorly understood. METHODS AND MATERIALS We developed a novel orthotopic mouse model of rectal cancer based on precisely defined endoscopic injections of tumor organoids that reflect tumor heterogeneity. Subsequently, we employed endoscopic- and computed tomography-guided RT and validated rectal tumor growth and response rates to therapy using small-animal magnetic resonance imaging and endoscopic follow-up. RESULTS Rectal tumor formation was successfully induced in all mice after 2 organoid injections. Clinically relevant RT regimens with 5 × 5 Gy significantly delayed clinical signs of tumor progression and significantly improved survival. Consistent with human disease, rectal tumor progression correlated with the development of liver and lung metastases. Notably, long-term survivors after RT showed no evidence of tumor recurrence, as demonstrated by in vivo radiologic tumor staging and histopathologic examination. CONCLUSIONS Our novel mouse model combines orthotopic tumor growth via noninvasive and precise rectal organoid injection and small-animal RT. This model holds significant promise for investigating the effect of tumor cell-intrinsic aspects, genetic alterations of the host, and exogenous factors (eg, nutrition or microbiota) on RT outcomes. Furthermore, it allows for the exploration of combination therapies involving chemotherapy, immunotherapy, or novel targeted therapies.
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Affiliation(s)
- Hannah Felchle
- Department of Radiation Oncology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Valentina Brunner
- Translational Cancer Research and Institute of Experimental Cancer Therapy, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Center for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany
| | - Tanja Groll
- Comparative Experimental Pathology, School of Medicine, Technical University of Munich, Munich, Germany; Institute of Pathology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Caroline N Walther
- Department of Radiation Oncology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Sophie M Nefzger
- Department of Radiation Oncology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Antonio E Zaurito
- Translational Cancer Research and Institute of Experimental Cancer Therapy, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Center for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany
| | - Miguel G Silva
- Center for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany; Institute of Molecular Oncology and Functional Genomics, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Julia Gissibl
- Department of Radiation Oncology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Geoffrey J Topping
- Department of Nuclear Medicine, School of Medicine, Technical University of Munich, Munich, Germany
| | - Laura Lansink Rotgerink
- Department of Radiation Oncology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany
| | - Dieter Saur
- Translational Cancer Research and Institute of Experimental Cancer Therapy, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Center for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany; German Cancer Consortium (DKTK), Partner-site Munich and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Katja Steiger
- Comparative Experimental Pathology, School of Medicine, Technical University of Munich, Munich, Germany; Institute of Pathology, School of Medicine, Technical University of Munich, Munich, Germany; German Cancer Consortium (DKTK), Partner-site Munich and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Stephanie E Combs
- Department of Radiation Oncology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; German Cancer Consortium (DKTK), Partner-site Munich and German Cancer Research Center (DKFZ), Heidelberg, Germany; Helmholtz Zentrum München, Institute of Radiation Medicine, Neuherberg, Germany
| | - Markus Tschurtschenthaler
- Translational Cancer Research and Institute of Experimental Cancer Therapy, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany; Center for Translational Cancer Research (TranslaTUM), School of Medicine, Technical University of Munich, Munich, Germany; German Cancer Consortium (DKTK), Partner-site Munich and German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Julius C Fischer
- Department of Radiation Oncology, Klinikum rechts der Isar, School of Medicine, Technical University of Munich, Munich, Germany.
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Bertilson M, von Hofsten O, Maltz JS, Taphorn K, Herzen J, Danielsson M. Analyzer-free hard x-ray interferometry. Phys Med Biol 2024; 69:045011. [PMID: 38232393 DOI: 10.1088/1361-6560/ad1f84] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 01/17/2024] [Indexed: 01/19/2024]
Abstract
Objective. To enable practical interferometry-based phase contrast CT using standard incoherent x-ray sources, we propose an imaging system where the analyzer grating is replaced by a high-resolution detector. Since there is no need to perform multiple exposures (with the analyzer grating at different positions) at each scan angle, this scheme is compatible with continuous-rotation CT apparatus, and has the potential to reduce patient radiation dose and patient motion artifacts.Approach. Grating-based x-ray interferometry is a well-studied technique for imaging soft tissues and highly scattering objects embedded in such tissues. In addition to the traditional x-ray absorption-based image, this technique allows reconstruction of the object phase and small-angle scattering information. When using conventional incoherent, polychromatic, hard x-ray tubes as sources, three gratings are usually employed. To sufficiently resolve the pattern generated in these interferometers with contemporary x-ray detectors, an analyzer grating is used, and consequently multiple images need to be acquired for each view angle. This adds complexity to the imaging system, slows image acquisition and thus increases sensitivity to patient motion, and is not dose efficient. By simulating image formation based on wave propagation, and proposing a novel phase retrieval algorithm based on a virtual grating, we assess the potential of a analyzer-grating-free system to overcome these limitations.Main results. We demonstrate that the removal of the analyzer-grating can produce equal image contrast-to-noise ratio at reduced dose (by a factor of 5), without prolonging scan duration.Significance.By demonstrating that an analyzer-free CT system, in conjuction with an efficient phase retrieval algorithm, can overcome the prohibitive dose and workflow penalties associated grating-stepping, an alternative path towards realizing clinical inteferometric CT appears possible.
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Affiliation(s)
- M Bertilson
- Eclipse Optics, Vasagatan 52, Stockholm, Sweden
| | | | - J S Maltz
- GE HealthCare, Waukesha, WI, United States of America
| | - K Taphorn
- Munich Institute of Biomedical Engineering, Technical University of Munich, D-85748, Garching, Germany
- Chair of Biomedical Physics, Department of Physics, TUM School of Natural Sciences, Technical University of Munich, D-85748 Garching, Germany
- Research Group Biomedical Imaging Physics, Department of Physics, TUM School of Natural Sciences, Technical University of Munich, D-85748 Garching, Germany
| | - J Herzen
- Munich Institute of Biomedical Engineering, Technical University of Munich, D-85748, Garching, Germany
- Chair of Biomedical Physics, Department of Physics, TUM School of Natural Sciences, Technical University of Munich, D-85748 Garching, Germany
- Research Group Biomedical Imaging Physics, Department of Physics, TUM School of Natural Sciences, Technical University of Munich, D-85748 Garching, Germany
| | - M Danielsson
- KTH Royal Institute of Technology, Department of Physics, Stockholm, Sweden
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Guo P, Zhang L, Lu J, Zhang H, Zhu X, Wu C, Zhan X, Yin H, Wang Z, Xu Y, Wang Z. Grating-based x-ray dark-field CT for lung cancer diagnosis in mice. Eur Radiol Exp 2024; 8:12. [PMID: 38270720 PMCID: PMC10810771 DOI: 10.1186/s41747-023-00399-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 10/20/2023] [Indexed: 01/26/2024] Open
Abstract
BACKGROUND The low absorption of x-rays in lung tissue and the poor resolution of conventional computed tomography (CT) limits its use to detect lung disease. However, x-ray dark-field imaging can sense the scattered x-rays deflected by the structures being imaged. This technique can facilitate the detection of small alveolar lesions that would be difficult to detect with conventional CT. Therefore, it may provide an alternative imaging modality to diagnose lung disease at an early stage. METHODS Eight mice were inoculated with lung cancers simultaneously. Each time two mice were scanned using a grating-based dark-field CT on days 4, 8, 12, and 16 after the introduction of the cancer cells. The detectability index was calculated between nodules and healthy parenchyma for both attenuation and dark-field modalities. High-resolution micro-CT and pathological examinations were used to crosscheck and validate our results. Paired t-test was used for comparing the ability of dark-field and attenuation modalities in pulmonary nodule detection. RESULTS The nodules were shown as a signal decrease in the dark-field modality and a signal increase in the attenuation modality. The number of nodules increased from day 8 to day 16, indicating disease progression. The detectability indices of dark-field modality were higher than those of attenuation modality (p = 0.025). CONCLUSIONS Compared with the standard attenuation CT, the dark-field CT improved the detection of lung nodules. RELEVANCE STATEMENT Dark-field CT has a higher detectability index than conventional attenuation CT in lung nodule detection. This technique could improve the early diagnosis of lung cancer. KEY POINTS • Lung cancer progression was observed using x-ray dark-field CT. • Dark-field modality complements with attenuation modality in lung nodule detection. • Dark-field modality showed a detectability index higher than that attenuation in nodule detection.
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Affiliation(s)
- Peiyuan Guo
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle & Radiation Imaging (Tsinghua University) of Ministry of Education, Beijing, China
- Institute for Precision Medicine, Tsinghua University, Beijing, China
| | - Li Zhang
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle & Radiation Imaging (Tsinghua University) of Ministry of Education, Beijing, China
- Institute for Precision Medicine, Tsinghua University, Beijing, China
| | - Jincheng Lu
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle & Radiation Imaging (Tsinghua University) of Ministry of Education, Beijing, China
- Institute for Precision Medicine, Tsinghua University, Beijing, China
| | - Huitao Zhang
- School of Mathematical Sciences, Capital Normal University, Beijing, China
| | - Xiaohua Zhu
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle & Radiation Imaging (Tsinghua University) of Ministry of Education, Beijing, China
| | - Chengpeng Wu
- Department of Engineering Physics, Tsinghua University, Beijing, China
- Key Laboratory of Particle & Radiation Imaging (Tsinghua University) of Ministry of Education, Beijing, China
| | - Xiangwen Zhan
- NHC Key Laboratory of Human Disease Comparative Medicine, Beijing Engineering Research Center for Experimental Animal Models of Human Critical Diseases, Institute of Laboratory Animal Sciences, Chinese Academy of Medical Sciences (CAMS) and Comparative Medicine Center, Peking Union Medical College (PUMC), Beijing, China
| | - Hongxia Yin
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zhenchang Wang
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yan Xu
- Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing, China.
| | - Zhentian Wang
- Department of Engineering Physics, Tsinghua University, Beijing, China.
- Key Laboratory of Particle & Radiation Imaging (Tsinghua University) of Ministry of Education, Beijing, China.
- Institute for Precision Medicine, Tsinghua University, Beijing, China.
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Urban T, Sauter AP, Frank M, Willer K, Noichl W, Bast H, Schick R, Herzen J, Koehler T, Gassert FT, Bodden JH, Fingerle AA, Gleich B, Renger B, Makowski MR, Pfeiffer F, Pfeiffer D. Dark-Field Chest Radiography Outperforms Conventional Chest Radiography for the Diagnosis and Staging of Pulmonary Emphysema. Invest Radiol 2023; 58:775-781. [PMID: 37276130 PMCID: PMC10581407 DOI: 10.1097/rli.0000000000000989] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/28/2023] [Indexed: 06/07/2023]
Abstract
OBJECTIVES Dark-field chest radiography (dfCXR) has recently reached clinical trials. Here we compare dfCXR to conventional radiography for the detection and staging of pulmonary emphysema. MATERIALS AND METHODS Subjects were included after a medically indicated computed tomography (CT) scan, showing either no lung impairments or different stages of emphysema. To establish a ground truth, all CT scans were assessed by 3 radiologists assigning emphysema severity scores based on the Fleischner Society classification scheme.Participants were imaged at a commercial chest radiography device and at a prototype for dfCXR, yielding both attenuation-based and dark-field images. Three radiologists blinded to CT score independently assessed images from both devices for presence and severity of emphysema (no, mild, moderate, severe).Statistical analysis included evaluation of receiver operating characteristic curves and pairwise comparison of adjacent Fleischner groups using an area under the curve (AUC)-based z test with a significance level of 0.05. RESULTS A total of 88 participants (54 men) with a mean age of 64 ± 12 years were included. Compared with conventional images (AUC = 0.73), readers were better able to identify emphysema with images from the dark-field prototype (AUC = 0.85, P = 0.005). Although ratings of adjacent emphysema severity groups with conventional radiographs differed only for trace and mild emphysema, ratings based on images from the dark-field prototype were different for trace and mild, mild and moderate, and moderate and confluent emphysema. CONCLUSIONS Dark-field chest radiography is superior to conventional chest radiography for emphysema diagnosis and staging, indicating the technique's potential as a low-dose diagnostic tool for emphysema assessment.
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Lin Q, Wu Z, Zan G, Huang M, Dang Z, Tian L, Guan Y, Liu G, Lu Y, Tian Y. High energy x-ray Talbot-Lau interferometer employing a microarray anode-structured target source to extend the field of view. Phys Med Biol 2023; 68:21NT01. [PMID: 37813100 DOI: 10.1088/1361-6560/ad0196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 10/09/2023] [Indexed: 10/11/2023]
Abstract
Objective. High energy and large field of view (FOV) phase contrast imaging is crucial for biological and even medical applications. Although some works have devoted to achieving a large FOV at high energy through bending gratings and so on, which would be extremely challenging in medical high energy imaging.Approach.We analyze the angular shadowing effect of planar gratings in high-energy x-ray Talbot-Lau interferometer (XTLI). Then we design and develop an inverse XTLI coupled with a microarray anode-structured target source to extend the FOV at high energy.Main results.Our experimental results demonstrate the benefit of the source in the inverse XTLI and a large FOV of 106.6 mm in the horizontal direction is achieved at 40 keV. Based on this system, experiments of a mouse demonstrate the potential advantage of phase contrast mode in imaging lung tissue.Significance.We extend the FOV in a compact XTLI using a microarray anode-structured target source coupled with an inverse geometry, which eliminates grating G0 and relaxes the fabrication difficulty of G2. We believe the established design idea and imaging system would facilitate the wide applications of XTLI in high energy phase contrast imaging.
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Affiliation(s)
- Qisi Lin
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, People's Republic of China
| | - Zhao Wu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, People's Republic of China
| | - Guibin Zan
- Sigray Inc., CA, United States of America
| | - Meng Huang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, People's Republic of China
- Ultrasonic Department, The First Affiliated Hospital of Anhui Medical University, Hefei, People's Republic of China
| | - Zheng Dang
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, People's Republic of China
| | - Lijiao Tian
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, People's Republic of China
| | - Yong Guan
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, People's Republic of China
| | - Gang Liu
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, People's Republic of China
| | - Yalin Lu
- Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, People's Republic of China
| | - Yangchao Tian
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, People's Republic of China
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Navarrete-León C, Doherty A, Savvidis S, Gerli MFM, Piredda G, Astolfo A, Bate D, Cipiccia S, Hagen CK, Olivo A, Endrizzi M. X-ray phase-contrast microtomography of soft tissues using a compact laboratory system with two-directional sensitivity. OPTICA 2023; 10:880-887. [PMID: 37841216 PMCID: PMC10575607 DOI: 10.1364/optica.487270] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 05/18/2023] [Accepted: 06/01/2023] [Indexed: 10/17/2023]
Abstract
X-ray microtomography is a nondestructive, three-dimensional inspection technique applied across a vast range of fields and disciplines, ranging from research to industrial, encompassing engineering, biology, and medical research. Phase-contrast imaging extends the domain of application of x-ray microtomography to classes of samples that exhibit weak attenuation, thus appearing with poor contrast in standard x-ray imaging. Notable examples are low-atomic-number materials, like carbon-fiber composites, soft matter, and biological soft tissues. We report on a compact and cost-effective system for x-ray phase-contrast microtomography. The system features high sensitivity to phase gradients and high resolution, requires a low-power sealed x-ray tube, a single optical element, and fits in a small footprint. It is compatible with standard x-ray detector technologies: in our experiments, we have observed that single-photon counting offered higher angular sensitivity, whereas flat panels provided a larger field of view. The system is benchmarked against known-material phantoms, and its potential for soft-tissue three-dimensional imaging is demonstrated on small-animal organs: a piglet esophagus and a rat heart. We believe that the simplicity of the setup we are proposing, combined with its robustness and sensitivity, will facilitate accessing quantitative x-ray phase-contrast microtomography as a research tool across disciplines, including tissue engineering, materials science, and nondestructive testing in general.
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Affiliation(s)
- Carlos Navarrete-León
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Adam Doherty
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Savvas Savvidis
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Mattia F. M. Gerli
- UCL Division of Surgery and Interventional Science, Royal Free Hospital, Rowland Hill Street, London, NW3 2PF, UK
- Stem Cell and Regenerative Medicine Section, Great Ormond Street Institute of Child Health, University College London, London, WC1N 1EH, UK
| | - Giovanni Piredda
- Research Center for Microtechnology, Vorarlberg University of Applied Sciences, Hochschulstr. 1, 6850, Dornbirn, Austria
| | - Alberto Astolfo
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - David Bate
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
- Nikon X-Tek Systems Ltd, Tring, Herts, HP23 4JX, UK
| | - Silvia Cipiccia
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Charlotte K. Hagen
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Alessandro Olivo
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Marco Endrizzi
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
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Pfeiffer F, Willer K, Viermetz M, Pfeiffer D. [Dark-field imaging and computed tomography : Novel X-ray-based contrast imaging modality with great promise for pulmonary imaging]. RADIOLOGIE (HEIDELBERG, GERMANY) 2023:10.1007/s00117-023-01161-4. [PMID: 37341743 DOI: 10.1007/s00117-023-01161-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Accepted: 05/03/2023] [Indexed: 06/22/2023]
Abstract
INTRODUCTION The spatial and contrast resolution of conventional planar or computed tomographic X‑ray techniques is not sufficient to investigate microstructures of tissues. Dark-field imaging with X‑rays is an emerging technology that recently provided the first clinical results and makes diagnostic use of interactions of the beams with tissue due to their wave character. APPLICATION Dark-field imaging can provide information about the microscopic structure or porosity of the tissue under investigation that is otherwise inaccessible. This makes it a valuable complement to conventional X‑ray imaging, which can only account for attenuation. Our results demonstrate that X‑ray dark-field imaging provides pictorial information about the underlying microstructure of the lung in humans. Given the close relationship between alveolar structure and the functional state of the lung, this is of great importance for diagnosis and therapy monitoring and may contribute to a better understanding of lung diseases in the future. In the early detection of chronic obstructive pulmonary disease, which is usually associated with structural impairment of the lung, this novel technique could help to facilitate its diagnosis. PERSPECTIVE The application of dark-field imaging to computed tomography is still under development because it is technically difficult. Meanwhile, a prototype for experimental application has been developed and is currently being tested on a variety of materials. Use in humans is conceivable especially for tissues whose microstructure favors characteristic interactions due to the wave nature of the X‑rays.
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Affiliation(s)
- Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics, School of Natural Sciences, Technical University of Munich, 85748, Garching, Deutschland.
- Munich Institute of Biomedical Engineering, Technical University of Munich, 85748, Garching, Deutschland.
- Department of Diagnostic and Interventional Radiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Deutschland.
| | - Konstantin Willer
- Chair of Biomedical Physics, Department of Physics, School of Natural Sciences, Technical University of Munich, 85748, Garching, Deutschland
- Munich Institute of Biomedical Engineering, Technical University of Munich, 85748, Garching, Deutschland
| | - Manuel Viermetz
- Chair of Biomedical Physics, Department of Physics, School of Natural Sciences, Technical University of Munich, 85748, Garching, Deutschland
- Munich Institute of Biomedical Engineering, Technical University of Munich, 85748, Garching, Deutschland
| | - Daniela Pfeiffer
- Department of Diagnostic and Interventional Radiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Deutschland
- Institute for Advanced Study, Technical University of Munich, 85748, Garching, Deutschland
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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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10
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Lioliou G, Roche i Morgó O, Marathe S, Wanelik K, Cipiccia S, Olivo A, Hagen CK. Cycloidal-spiral sampling for three-modal x-ray CT flyscans with two-dimensional phase sensitivity. Sci Rep 2022; 12:21336. [PMID: 36494470 PMCID: PMC9734192 DOI: 10.1038/s41598-022-25999-1] [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: 08/02/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
We present a flyscan compatible acquisition scheme for three-modal X-Ray Computed Tomography (CT) with two-dimensional phase sensitivity. Our approach is demonstrated using a "beam tracking" setup, through which a sample's attenuation, phase (refraction) and scattering properties can be measured from a single frame, providing three complementary contrast channels. Up to now, such setups required the sample to be stepped at each rotation angle to sample signals at an adequate rate, to prevent resolution losses, anisotropic resolution, and under-sampling artefacts. However, the need for stepping necessitated a step-and-shoot implementation, which is affected by motors' overheads and increases the total scan time. By contrast, our proposed scheme, by which continuous horizontal and vertical translations of the sample are integrated with its rotation (leading to a "cycloidal-spiral" trajectory), is fully compatible with continuous scanning (flyscans). This leads to greatly reduced scan times while largely preserving image quality and isotropic resolution.
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Affiliation(s)
- G. Lioliou
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
| | - O. Roche i Morgó
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
| | - S. Marathe
- grid.18785.330000 0004 1764 0696Diamond Light Source, Harwell Science and Innovation Campus, Fermi Avenue, Didcot, OX11 0DE UK
| | - K. Wanelik
- grid.18785.330000 0004 1764 0696Diamond Light Source, Harwell Science and Innovation Campus, Fermi Avenue, Didcot, OX11 0DE UK
| | - S. Cipiccia
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
| | - A. Olivo
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
| | - C. K. Hagen
- grid.83440.3b0000000121901201Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, London, WC1E 6BT UK
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11
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Alloo SJ, Paganin DM, Morgan KS, Kitchen MJ, Stevenson AW, Mayo SC, Li HT, Kennedy BM, Maksimenko A, Bowden JC, Pavlov KM. Dark-field tomography of an attenuating object using intrinsic x-ray speckle tracking. J Med Imaging (Bellingham) 2022; 9:031502. [PMID: 35155717 PMCID: PMC8820385 DOI: 10.1117/1.jmi.9.3.031502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 12/21/2021] [Indexed: 11/14/2022] Open
Abstract
Purpose: We investigate how an intrinsic speckle tracking approach to speckle-based x-ray imaging is used to extract an object's effective dark-field (DF) signal, which is capable of providing object information in three dimensions. Approach: The effective DF signal was extracted using a Fokker-Planck type formalism, which models the deformations of illuminating reference beam speckles due to both coherent and diffusive scatter from the sample. Here, we assumed that (a) small-angle scattering fans at the exit surface of the sample are rotationally symmetric and (b) the object has both attenuating and refractive properties. The associated inverse problem of extracting the effective DF signal was numerically stabilized using a "weighted determinants" approach. Results: Effective DF projection images, as well as the DF tomographic reconstructions of the wood sample, are presented. DF tomography was performed using a filtered back projection reconstruction algorithm. The DF tomographic reconstructions of the wood sample provided complementary, and otherwise inaccessible, information to augment the phase contrast reconstructions, which were also computed. Conclusions: An intrinsic speckle tracking approach to speckle-based imaging can tomographically reconstruct an object's DF signal at a low sample exposure and with a simple experimental setup. The obtained DF reconstructions have an image quality comparable to alternative x-ray DF techniques.
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Affiliation(s)
- Samantha J. Alloo
- University of Canterbury, School of Physical and Chemical Sciences, Christchurch, New Zealand,Address all correspondence to Samantha J. Alloo, ; Konstantin M. Pavlov,
| | - David M. Paganin
- Monash University, School of Physics and Astronomy, Melbourne, Victoria, Australia
| | - Kaye S. Morgan
- Monash University, School of Physics and Astronomy, Melbourne, Victoria, Australia
| | - Marcus J. Kitchen
- Monash University, School of Physics and Astronomy, Melbourne, Victoria, Australia
| | | | - Sheridan C. Mayo
- Commonwealth Scientific and Industrial Research Organisation, Clayton, Victoria, Australia
| | - Heyang T. Li
- University of Canterbury, School of Mathematics and Statistics, Christchurch, New Zealand
| | - Ben M. Kennedy
- University of Canterbury, School of Earth and Environment, Christchurch, New Zealand
| | | | - Joshua C. Bowden
- Commonwealth Scientific and Industrial Research Organisation, Clayton, Victoria, Australia
| | - Konstantin M. Pavlov
- University of Canterbury, School of Physical and Chemical Sciences, Christchurch, New Zealand,Monash University, School of Physics and Astronomy, Melbourne, Victoria, Australia,University of New England, Armidale, New South Wales, Australia,Address all correspondence to Samantha J. Alloo, ; Konstantin M. Pavlov,
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12
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Abstract
X-ray computed tomography (CT) is one of the most commonly used diagnostic three-dimensional imaging modalities today. Conventionally, this noninvasive technique generates contrast by measuring the X-ray attenuation properties of different tissues. Considering the wave nature of X-rays, complementary contrast can be achieved by further measuring their small-angle scattering (dark-field) properties. This provides additional valuable diagnostic information on otherwise unresolved tissue microstructure. In our work, we have translated this wave-optical mechanism from the optical bench to a human-sized prototype CT system. This involved the integration of an interferometer into a clinical CT gantry and overcoming several associated challenges regarding vibrations, continuous gantry rotation, and large field of view. This development puts complementary X-ray contrast within reach for real-word medical applications. X-ray computed tomography (CT) is one of the most commonly used three-dimensional medical imaging modalities today. It has been refined over several decades, with the most recent innovations including dual-energy and spectral photon-counting technologies. Nevertheless, it has been discovered that wave-optical contrast mechanisms—beyond the presently used X-ray attenuation—offer the potential of complementary information, particularly on otherwise unresolved tissue microstructure. One such approach is dark-field imaging, which has recently been introduced and already demonstrated significantly improved radiological benefit in small-animal models, especially for lung diseases. Until now, however, dark-field CT could not yet be translated to the human scale and has been restricted to benchtop and small-animal systems, with scan durations of several minutes or more. This is mainly because the adaption and upscaling to the mechanical complexity, speed, and size of a human CT scanner so far remained an unsolved challenge. Here, we now report the successful integration of a Talbot–Lau interferometer into a clinical CT gantry and present dark-field CT results of a human-sized anthropomorphic body phantom, reconstructed from a single rotation scan performed in 1 s. Moreover, we present our key hardware and software solutions to the previously unsolved roadblocks, which so far have kept dark-field CT from being translated from the optical bench into a rapidly rotating CT gantry, with all its associated challenges like vibrations, continuous rotation, and large field of view. This development enables clinical dark-field CT studies with human patients in the near future.
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13
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Retrieval of 3D information in X-ray dark-field imaging with a large field of view. Sci Rep 2021; 11:23504. [PMID: 34873265 PMCID: PMC8648862 DOI: 10.1038/s41598-021-02960-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/18/2021] [Indexed: 11/08/2022] Open
Abstract
X-ray dark-field imaging is a widely researched imaging technique, with many studies on samples of very different dimensions and at very different resolutions. However, retrieval of three-dimensional (3D) information for human thorax sized objects has not yet been demonstrated. We present a method, similar to classic tomography and tomosynthesis, to obtain 3D information in X-ray dark-field imaging. Here, the sample is moved through the divergent beam of a Talbot-Lau interferometer. Projections of features at different distances from the source seemingly move with different velocities over the detector, due to the cone beam geometry. The reconstruction of different focal planes exploits this effect. We imaged a chest phantom and were able to locate different features in the sample (e.g. the ribs, and two sample vials filled with water and air and placed in the phantom) to corresponding focal planes. Furthermore, we found that image quality and detectability of features is sufficient for image reconstruction with a dose of 68 μSv at an effective pixel size of [Formula: see text]. Therefore, we successfully demonstrated that the presented method is able to retrieve 3D information in X-ray dark-field imaging.
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14
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Piovesan A, Vancauwenberghe V, Van De Looverbosch T, Verboven P, Nicolaï B. X-ray computed tomography for 3D plant imaging. TRENDS IN PLANT SCIENCE 2021; 26:1171-1185. [PMID: 34404587 DOI: 10.1016/j.tplants.2021.07.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/05/2021] [Accepted: 07/21/2021] [Indexed: 06/13/2023]
Abstract
X-ray computed tomography (CT) is a valuable tool for 3D imaging of plant tissues and organs. Applications include the study of plant development and organ morphogenesis, as well as modeling of transport processes in plants. Some challenges remain, however, including attaining higher contrast for easier quantification, increasing the resolution for imaging subcellular features, and decreasing image acquisition and processing time for high-throughput phenotyping. In addition, phase contrast, multispectral, dark-field, soft X-ray, and time-resolved imaging are emerging. At the same time, a large amount of 3D image data are becoming available, posing challenges for data management. We review recent advances in the area of X-ray CT for plant imaging, and describe opportunities for using such images for studying transport processes in plants.
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Affiliation(s)
- Agnese Piovesan
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium
| | - Valérie Vancauwenberghe
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium
| | - Tim Van De Looverbosch
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium
| | - Pieter Verboven
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium.
| | - Bart Nicolaï
- Katholieke Universiteit (KU) Leuven, Division MeBioS (Mechatronics, Biostatistics, and Sensors) - Postharvest Group, Willem de Croylaan 42, BE-3001 Leuven, Belgium; Flanders Centre of Postharvest Technology (VCBT), Willem de Croylaan 42, BE-3001 Leuven, Belgium
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15
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Gassert FT, Urban T, Frank M, Willer K, Noichl W, Buchberger P, Schick R, Koehler T, von Berg J, Fingerle AA, Sauter AP, Makowski MR, Pfeiffer D, Pfeiffer F. X-ray Dark-Field Chest Imaging: Qualitative and Quantitative Results in Healthy Humans. Radiology 2021; 301:389-395. [PMID: 34427464 DOI: 10.1148/radiol.2021210963] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Background X-ray dark-field radiography takes advantage of the wave properties of x-rays, with a relatively high signal in the lungs due to the many air-tissue interfaces in the alveoli. Purpose To describe the qualitative and quantitative characteristics of x-ray dark-field images in healthy human subjects. Materials and Methods Between October 2018 and January 2020, patients of legal age who underwent chest CT as part of their diagnostic work-up were screened for study participation. Inclusion criteria were a normal chest CT scan, the ability to consent, and the ability to stand upright without help. Exclusion criteria were pregnancy, serious medical conditions, and changes in the lung tissue, such as those due to cancer, pleural effusion, atelectasis, emphysema, infiltrates, ground-glass opacities, or pneumothorax. Images of study participants were obtained by using a clinical x-ray dark-field prototype, recently constructed and commissioned at the authors' institution, to simultaneously acquire both attenuation-based and dark-field thorax radiographs. Each subject's total dark-field signal was correlated with his or her lung volume, and the dark-field coefficient was correlated with age, sex, weight, and height. Results Overall, 40 subjects were included in this study (average age, 62 years ± 13 [standard deviation]; 26 men, 14 women). Normal human lungs have high signal, while the surrounding osseous structures and soft tissue have very low and no signal, respectively. The average dark-field signal was 2.5 m-1 ± 0.4 of examined lung tissue. There was a correlation between the total dark-field signal and the lung volume (r = 0.61, P < .001). No difference was found between men and women (P = .78). Also, age (r = -0.18, P = .26), weight (r = 0.24, P = .13), and height (r = 0.01, P = .96) did not influence dark-field signal. Conclusion This study introduces qualitative and quantitative values for x-ray dark-field imaging in healthy human subjects. The quantitative x-ray dark-field coefficient is independent from demographic subject parameters, emphasizing its potential in diagnostic assessment of the lung. ©RSNA, 2021 See also the editorial by Hatabu and Madore in this issue.
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Affiliation(s)
- Florian T Gassert
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Theresa Urban
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Manuela Frank
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Konstantin Willer
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Wolfgang Noichl
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Philipp Buchberger
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Rafael Schick
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Thomas Koehler
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Jens von Berg
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Alexander A Fingerle
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Andreas P Sauter
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Marcus R Makowski
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Daniela Pfeiffer
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
| | - Franz Pfeiffer
- From the Department of Diagnostic and Interventional Radiology, School of Medicine & Klinikum Rechts der Isar, Technical University of Munich, Ismaningerstr 22, 81675 Munich, Germany (F.T.G., A.A.F., A.P.S., M.R.M., D.P., F.P.); Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany (T.U., M.F., K.W., W.N., P.B., R.S., F.P.); and Philips Research, Hamburg, Germany (T.K., J.v.B.)
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16
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Burkhardt R, Gora T, Fingerle AA, Sauter AP, Meurer F, Gassert FT, Dobiasch S, Schilling D, Feuchtinger A, Walch AK, Multhoff G, Herzen J, Noël PB, Rummeny EJ, Combs SE, Schmid TE, Pfeiffer F, Wilkens JJ. In-vivo X-ray dark-field computed tomography for the detection of radiation-induced lung damage in mice. Phys Imaging Radiat Oncol 2021; 20:11-16. [PMID: 34611553 PMCID: PMC8476771 DOI: 10.1016/j.phro.2021.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 09/13/2021] [Accepted: 09/13/2021] [Indexed: 11/22/2022] Open
Abstract
Radiation-induced lung damage was observed using X-ray dark-field tomography. In this pre-clinical study, mouse lungs were irradiated and subsequently imaged. We report increased sensitivity of X-ray dark-field tomography over absorption-based tomography.
Background and Purpose Radiotherapy of thoracic tumours can lead to side effects in the lung, which may benefit from early diagnosis. We investigated the potential of X-ray dark-field computed tomography by a proof-of-principle murine study in a clinically relevant radiotherapeutic setting aiming at the detection of radiation-induced lung damage. Material and Methods Six mice were irradiated with 20 Gy to the entire right lung. Together with five unirradiated control mice, they were imaged using computed tomography with absorption and dark-field contrast before and 16 weeks post irradiation. Mean pixel values for the right and left lung were calculated for both contrasts, and the right-to-left-ratio R of these means was compared. Radiologists also assessed the tomograms acquired 16 weeks post irradiation. Sensitivity, specificity, inter- and intra-reader accuracy were evaluated. Results In absorption contrast the group-average of R showed no increase in the control group and increased by 7% (p = 0.005) in the irradiated group. In dark-field contrast, it increased by 2% in the control group and by 14% (p = 0.005) in the irradiated group. Specificity was 100% for both contrasts but sensitivity was almost four times higher using dark-field tomography. Two cases were missed by absorption tomography but were detected by dark-field tomography. Conclusions The applicability of X-ray dark-field computed tomography for the detection of radiation-induced lung damage was demonstrated in a pre-clinical mouse model. The presented results illustrate the differences between dark-field and absorption contrast and show that dark-field tomography could be advantageous in future clinical settings.
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Affiliation(s)
- Rico Burkhardt
- Department of Radiation Oncology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany.,Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Neuherberg, Germany.,Physics Department, Technical University of Munich, Garching, Germany
| | - Thomas Gora
- Department of Radiation Oncology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany
| | - Alexander A Fingerle
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany
| | - Andreas P Sauter
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany
| | - Felix Meurer
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany
| | - Florian T Gassert
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany
| | - Sophie Dobiasch
- Department of Radiation Oncology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany.,Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Neuherberg, Germany
| | - Daniela Schilling
- Department of Radiation Oncology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany.,Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Neuherberg, Germany
| | - Annette Feuchtinger
- Abteilung Analytische Pathologie, Helmholtz Zentrum München, Neuherberg, Germany
| | - Axel K Walch
- Abteilung Analytische Pathologie, Helmholtz Zentrum München, Neuherberg, Germany
| | - Gabriele Multhoff
- Department of Radiation Oncology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany.,Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Neuherberg, Germany.,TranslaTUM, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany
| | - Julia Herzen
- Physics Department, Technical University of Munich, Garching, Germany.,Chair of Biomedical Physics, Technical University of Munich, Garching, Germany.,Munich School of BioEngineering (MSB), Technical University of Munich, Garching, Germany
| | - Peter B Noël
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany
| | - Ernst J Rummeny
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany
| | - Stephanie E Combs
- Department of Radiation Oncology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany.,Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Neuherberg, Germany.,Deutsches Konsortium für Translationale Krebsforschung (DKTK), Partner Site Munich, Munich, Germany
| | - Thomas E Schmid
- Department of Radiation Oncology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany.,Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Neuherberg, Germany
| | - Franz Pfeiffer
- Physics Department, Technical University of Munich, Garching, Germany.,Department of Diagnostic and Interventional Radiology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany.,Chair of Biomedical Physics, Technical University of Munich, Garching, Germany.,Munich School of BioEngineering (MSB), Technical University of Munich, Garching, Germany
| | - Jan J Wilkens
- Department of Radiation Oncology, Technical University of Munich, School of Medicine and Klinikum rechts der Isar, Munich, Germany.,Physics Department, Technical University of Munich, Garching, Germany.,Chair of Biomedical Physics, Technical University of Munich, Garching, Germany
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17
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Sauter AP, Andrejewski J, Frank M, Willer K, Herzen J, Meurer F, Fingerle AA, Makowski MR, Pfeiffer F, Pfeiffer D. Correlation of image quality parameters with tube voltage in X-ray dark-field chest radiography: a phantom study. Sci Rep 2021; 11:14130. [PMID: 34239040 PMCID: PMC8266828 DOI: 10.1038/s41598-021-93716-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 06/23/2021] [Indexed: 12/26/2022] Open
Abstract
Grating-based X-ray dark-field imaging is a novel imaging modality with enormous technical progress during the last years. It enables the detection of microstructure impairment as in the healthy lung a strong dark-field signal is present due to the high number of air-tissue interfaces. Using the experience from setups for animal imaging, first studies with a human cadaver could be performed recently. Subsequently, the first dark-field scanner for in-vivo chest imaging of humans was developed. In the current study, the optimal tube voltage for dark-field radiography of the thorax in this setup was examined using an anthropomorphic chest phantom. Tube voltages of 50–125 kVp were used while maintaining a constant dose-area-product. The resulting dark-field and attenuation radiographs were evaluated in a reader study as well as objectively in terms of contrast-to-noise ratio and signal strength. We found that the optimum tube voltage for dark-field imaging is 70 kVp as here the most favorable combination of image quality, signal strength, and sharpness is present. At this voltage, a high image quality was perceived in the reader study also for attenuation radiographs, which should be sufficient for routine imaging. The results of this study are fundamental for upcoming patient studies with living humans.
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Affiliation(s)
- Andreas P Sauter
- Department of Diagnostic and Interventional Radiology, School of Medicine and Klinikum Rechts Der Isar, Technical University of Munich, Ismaningerstr. 22, 81675, Munich, Germany.
| | - Jana Andrejewski
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany
| | - Manuela Frank
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany
| | - Konstantin Willer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany
| | - Julia Herzen
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany
| | - Felix Meurer
- Department of Diagnostic and Interventional Radiology, School of Medicine and Klinikum Rechts Der Isar, Technical University of Munich, Ismaningerstr. 22, 81675, Munich, Germany
| | - Alexander A Fingerle
- Department of Diagnostic and Interventional Radiology, School of Medicine and Klinikum Rechts Der Isar, Technical University of Munich, Ismaningerstr. 22, 81675, Munich, Germany
| | - Markus R Makowski
- Department of Diagnostic and Interventional Radiology, School of Medicine and Klinikum Rechts Der Isar, Technical University of Munich, Ismaningerstr. 22, 81675, Munich, Germany
| | - Franz Pfeiffer
- Department of Diagnostic and Interventional Radiology, School of Medicine and Klinikum Rechts Der Isar, Technical University of Munich, Ismaningerstr. 22, 81675, Munich, Germany.,Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Garching, Germany
| | - Daniela Pfeiffer
- Department of Diagnostic and Interventional Radiology, School of Medicine and Klinikum Rechts Der Isar, Technical University of Munich, Ismaningerstr. 22, 81675, Munich, Germany
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18
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Hagen CK, Endrizzi M, Towns R, Meganck JA, Olivo A. A Preliminary Investigation into the Use of Edge Illumination X-ray Phase Contrast Micro-CT for Preclinical Imaging. Mol Imaging Biol 2021; 22:539-548. [PMID: 31250331 PMCID: PMC7250795 DOI: 10.1007/s11307-019-01396-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Purpose To enable a preliminary assessment of the suitability of edge illumination (EI) x-ray phase contrast (XPC) micro x-ray computed tomography (micro-CT) to preclinical imaging. Specifically, to understand how different acquisition schemes and their combination with dedicated data processing affect contrast-to-noise ratio (CNR) and spatial resolution, while providing control over scan time and radiation dose delivery. Procedures Deceased mice (n = 3) were scanned with an EI XPC micro-CT setup operated under different settings, leading to scan times between 18 h and 13 min. For the shortest scan, the entrance dose was measured with a calibrated PTW 23344 ion chamber. Different data processing methods were applied, retrieving either separate attenuation and phase images, or hybrid (combined attenuation and phase) images. A quantitative comparison was performed based on CNR and spatial resolution measurements for a soft tissue interface. Results All phase-based images have led to a higher CNR for the considered soft tissue interface than the attenuation image, independent of scan time. The best relative CNR (a sixfold increase) was observed in one of the hybrid images. Spatial resolution was found to be connected to scan time, with a resolution of approximately 20 μm and 60 μm achieved for the longest and shortest scans, respectively. An entrance dose of approximately 300 mGy was estimated for the scan performed within 13 min. Conclusions Despite their preliminary nature, our results suggest that EI XPC bears potential for enhancing the utility of preclinical micro-CT, and, pending further research and development, could ultimately become a valuable technique in this field.
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Affiliation(s)
- Charlotte K Hagen
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK.
| | - Marco Endrizzi
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
| | - Rebecca Towns
- Biological Services, University College London, Gower Street, London, WC1E 6BT, UK
| | - Jeffrey A Meganck
- Research and Development, Life Sciences Technology, PerkinElmer, 68 Elm St, Hopkinton, MA, 01748, USA
| | - Alessandro Olivo
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London, WC1E 6BT, UK
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19
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Andrejewski J, De Marco F, Willer K, Noichl W, Gustschin A, Koehler T, Meyer P, Kriner F, Fischer F, Braun C, Fingerle AA, Herzen J, Pfeiffer F, Pfeiffer D. Whole-body x-ray dark-field radiography of a human cadaver. Eur Radiol Exp 2021; 5:6. [PMID: 33495889 PMCID: PMC7835263 DOI: 10.1186/s41747-020-00201-1] [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: 07/22/2020] [Accepted: 12/03/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Grating-based x-ray dark-field and phase-contrast imaging allow extracting information about refraction and small-angle scatter, beyond conventional attenuation. A step towards clinical translation has recently been achieved, allowing further investigation on humans. METHODS After the ethics committee approval, we scanned the full body of a human cadaver in anterior-posterior orientation. Six measurements were stitched together to form the whole-body image. All radiographs were taken at a three-grating large-object x-ray dark-field scanner, each lasting about 40 s. Signal intensities of different anatomical regions were assessed. The magnitude of visibility reduction caused by beam hardening instead of small-angle scatter was analysed using different phantom materials. Maximal effective dose was 0.3 mSv for the abdomen. RESULTS Combined attenuation and dark-field radiography are technically possible throughout a whole human body. High signal levels were found in several bony structures, foreign materials, and the lung. Signal levels were 0.25 ± 0.13 (mean ± standard deviation) for the lungs, 0.08 ± 0.06 for the bones, 0.023 ± 0.019 for soft tissue, and 0.30 ± 0.02 for an antibiotic bead chain. We found that phantom materials, which do not produce small-angle scatter, can generate a strong visibility reduction signal. CONCLUSION We acquired a whole-body x-ray dark-field radiograph of a human body in few minutes with an effective dose in a clinical acceptable range. Our findings suggest that the observed visibility reduction in the bone and metal is dominated by beam hardening and that the true dark-field signal in the lung is therefore much higher than that of the bone.
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Affiliation(s)
- Jana Andrejewski
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany.
| | - Fabio De Marco
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Konstantin Willer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Wolfgang Noichl
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Alex Gustschin
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | | | - Pascal Meyer
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Fabian Kriner
- Institut für Rechtsmedizin, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Florian Fischer
- Institut für Rechtsmedizin, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Christian Braun
- Institut für Rechtsmedizin, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Alexander A Fingerle
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, 81675, Munich, Germany
| | - Julia Herzen
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany.,Department of Diagnostic and Interventional Radiology, Technical University of Munich, 81675, Munich, Germany
| | - Daniela Pfeiffer
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, 81675, Munich, Germany
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20
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Notohamiprodjo S, Treitl KM, Hauke C, Sutter SM, Auweter S, Pfeiffer F, Reiser MF, Hellbach K. Imaging characteristics of intravascular spherical contrast agents for grating-based x-ray dark-field imaging – effects of concentrations, spherical sizes and applied voltage. Sci Rep 2020; 10:9405. [PMID: 32523085 PMCID: PMC7287139 DOI: 10.1038/s41598-020-66395-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 05/14/2020] [Indexed: 11/09/2022] Open
Abstract
AbstractThis study investigates the x-ray scattering characteristics of microsphere particles in x-ray-grating-based interferometric imaging at different concentrations, bubble sizes and tube voltages (kV). Attenuation (ATI), dark-field (DFI) and phase-contrast (PCI) images were acquired. Signal-to-noise (SNR) and contrast-to-noise ratios with water (CNRw) and air as reference (CNRa) were determined. In all modalities, a linear relationship between SNR and microbubbles concentration, respectively, microsphere size was found. A significant gain of SNR was found when varying kV. SNR was significantly higher in DFI and PCI than ATI. The highest gain of SNR was shown at 60 kV for all media in ATI and DFI, at 80 kV for PCI. SNR for all media was significantly higher compared to air and was slightly lower compared to water. A linear relationship was found between CNRa, CNRw, concentration and size. With increasing concentration and decreasing size, CNRa and CNRw increased in DFI, but decreased in PCI. Best CNRa and CNRw was found at specific combination of kV and concentration/size. Highest average CNRa and CNRw was found for microspheres in ATI and PCI, for microbubbles in DFI. Microspheres are a promising contrast-media for grating-based-interferometry, if kV, microsphere size and concentration are appropriately combined.
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21
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Graetz J, Balles A, Hanke R, Zabler S. Review and experimental verification of x-ray dark-field signal interpretations with respect to quantitative isotropic and anisotropic dark-field computed tomography. Phys Med Biol 2020; 65:235017. [PMID: 32916662 DOI: 10.1088/1361-6560/abb7c6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Talbot(-Lau) interferometric x-ray and neutron dark-field imaging has, over the past decade, gained substantial interest for its ability to provide insights into a sample's microstructure below the imaging resolution by means of ultra small angle scattering effects. Quantitative interpretations of such images depend on models of the signal origination process that relate the observable image contrast to underlying physical processes. A review of such models is given here and their relation to the wave optical derivations by Yashiro et al and Lynch et al as well as to small angle scattering is discussed. Fresnel scaling is introduced to explain the characteristic distance dependence observed in cone beam geometries. Moreover, a model describing the anisotropic signals of fibrous objects is derived. The Yashiro-Lynch model is experimentally verified both in radiographic and tomographic imaging in a monochromatic synchrotron setting, considering both the effects of material and positional dependence of the resulting dark-field contrast. The effect of varying sample-detector distance on the dark-field signal is shown to be non-negligible for tomographic imaging, yet can be largely compensated for by symmetric acquisition trajectories. The derived orientation dependence of the dark-field contrast of fibrous materials both with respect to variations in autocorrelation width and scattering cross section is experimentally validated using carbon fiber reinforced rods.
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Affiliation(s)
- J Graetz
- Lehrstuhl für Röntgenmikroskopie, Universität Würzburg, Josef-Martin-Weg 63, 97074 Würzburg, Germany. Fraunhofer IIS, division EZRT, Flugplatzstraße 75, 90768 Fürth / Josef-Martin-Weg 63, 97074 Würzburg, Germany
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22
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Singh R, Wu W, Wang G, Kalra MK. Artificial intelligence in image reconstruction: The change is here. Phys Med 2020; 79:113-125. [DOI: 10.1016/j.ejmp.2020.11.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/06/2020] [Accepted: 11/07/2020] [Indexed: 12/19/2022] Open
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23
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Günther B, Gradl R, Jud C, Eggl E, Huang J, Kulpe S, Achterhold K, Gleich B, Dierolf M, Pfeiffer F. The versatile X-ray beamline of the Munich Compact Light Source: design, instrumentation and applications. JOURNAL OF SYNCHROTRON RADIATION 2020; 27:1395-1414. [PMID: 32876618 PMCID: PMC7467334 DOI: 10.1107/s1600577520008309] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 06/22/2020] [Indexed: 05/08/2023]
Abstract
Inverse Compton scattering provides means to generate low-divergence partially coherent quasi-monochromatic, i.e. synchrotron-like, X-ray radiation on a laboratory scale. This enables the transfer of synchrotron techniques into university or industrial environments. Here, the Munich Compact Light Source is presented, which is such a compact synchrotron radiation facility based on an inverse Compton X-ray source (ICS). The recent improvements of the ICS are reported first and then the various experimental techniques which are most suited to the ICS installed at the Technical University of Munich are reviewed. For the latter, a multipurpose X-ray application beamline with two end-stations was designed. The beamline's design and geometry are presented in detail including the different set-ups as well as the available detector options. Application examples of the classes of experiments that can be performed are summarized afterwards. Among them are dynamic in vivo respiratory imaging, propagation-based phase-contrast imaging, grating-based phase-contrast imaging, X-ray microtomography, K-edge subtraction imaging and X-ray spectroscopy. Finally, plans to upgrade the beamline in order to enhance its capabilities are discussed.
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Affiliation(s)
- Benedikt Günther
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Regine Gradl
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Christoph Jud
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Elena Eggl
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Juanjuan Huang
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Stephanie Kulpe
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Klaus Achterhold
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Bernhard Gleich
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Martin Dierolf
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
| | - Franz Pfeiffer
- Department of Physics, Technical University of Munich, James-Franck-Straße 1, 85748 Garching, Germany
- Munich School of BioEngineering, Technical University of Munich, Boltzmannstraße 11, 85748 Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675 Munich, Germany
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24
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Abstract
Since their discovery by Wilhelm Conrad Röntgen in 1895, X-rays have become the most widely available, typically fastest, and usually most cost-effective medical imaging modality today. From the early radiographic approaches using X-ray films as detectors, the portfolio of medical X-ray imaging devices developed into a large range of dedicated instrumentation for various applications. While X-ray imaging has come a long way, there are some physical properties of X-rays, which have not yet been fully exploited, and which may offer quite some room for further enhancements of current X-ray imaging equipment. Firstly, X-ray imaging today is mainly black and white, despite the fact that X-ray generators actually create a full spectrum of X-ray energies, and that the interactions of X-rays that occur within the human body are not the same for all energies and every material. Exploiting these spectral dependencies allows to not only obtain a black and white CT image, but also to obtain more molecularly specific information, which is relevant particularly in oncological precision radiology. The second aspect of X-rays, and so far in radiology mainly neglected and unused, is the physical fact that X-rays can also be interpreted in the wave picture, and not only as presently been done in the particle picture. If interpreted as waves, X-rays-just like visible light-experience a phase shift in matter, and this-if exploited correctly-can produce a new class of X-ray images, which then depict the wave interactions of X-rays with matter, rather than only the attenuating properties, as done until now.
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25
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Zhou J, Yi Z, Fu Q. Dynamic decreased expression and hypermethylation of secreted frizzled-related protein 1 and 4 over the course of pulmonary fibrosis in mice. Life Sci 2019; 218:241-252. [PMID: 30586565 DOI: 10.1016/j.lfs.2018.12.041] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/18/2018] [Accepted: 12/22/2018] [Indexed: 01/08/2023]
Abstract
Aberrantly activated Wnt signaling pathway and dysregulation of extracellular antagonists of Wnt signaling have been revealed in pulmonary fibrosis. In this study we evaluated the expression of secreted frizzled-related proteins (SFRPs) and their aberrant promoter methylation to investigate the involvement of epigenetic regulation in pulmonary fibrosis. The pulmonary fibrosis induced by intratracheal injection of bleomycin (BLM) into mice was adopted. The transcription and relative protein expression of SFRPs were detected at Day 7 (D7), D14, and D21. DNA methylation analysis was performed by methylation-specific polymerase chain reaction (MSP). A DNA methyltransferase (DNMT) inhibitor (5-aza-2'-deoxycytidine; 5-aza) was used for demethylation and the relative β-catenin expression levels were measured to assess overactivity of the canonical Wnt signaling pathway. The transcription and protein expression of SFRP1 significantly decreased at D14 and D21, whereas the transcription and protein expression of SFRP4 significantly decreased at D7 and stayed downregulated until D21. The significantly hypermethylated promoters of SFRP1 and SFRP4 resulted in impaired transcription and decreased expression during pulmonary fibrosis in mice. Besides, reactivation of SFRP1 and SFRP4 by 5-aza reduced β-catenin mRNA and protein expression in vivo and in vitro. Animal experiments confirmed that 5-aza could significantly alleviate bleomycin-induced pulmonary fibrosis in mice. Thus, changes of promoter hypermethylation might downregulate SFRP1 and SFRP4 at different stages of pulmonary fibrosis, and the finding supports the usefulness of DNMT inhibitors, which might effectively reverse activation of β-catenin and reduce pulmonary fibrosis in mice. These data provide a possible new direction in the research on pulmonary fibrosis treatments.
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Affiliation(s)
- Junfei Zhou
- Department of Rheumatology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, PR China
| | - Zheng Yi
- Department of Rheumatology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing 100020, PR China.
| | - Qiang Fu
- Department of Rheumatology, The First Affiliated Hospital of University of South China, HengYang 421001, PR China
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26
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Quantitative morphometric analysis of adult teleost fish by X-ray computed tomography. Sci Rep 2018; 8:16531. [PMID: 30410001 PMCID: PMC6224569 DOI: 10.1038/s41598-018-34848-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 10/22/2018] [Indexed: 12/11/2022] Open
Abstract
Vertebrate models provide indispensable paradigms to study development and disease. Their analysis requires a quantitative morphometric study of the body, organs and tissues. This is often impeded by pigmentation and sample size. X-ray micro-computed tomography (micro-CT) allows high-resolution volumetric tissue analysis, largely independent of sample size and transparency to visual light. Importantly, micro-CT data are inherently quantitative. We report a complete pipeline of high-throughput 3D data acquisition and image analysis, including tissue preparation and contrast enhancement for micro-CT imaging down to cellular resolution, automated data processing and organ or tissue segmentation that is applicable to comparative 3D morphometrics of small vertebrates. Applied to medaka fish, we first create an annotated anatomical atlas of the entire body, including inner organs as a quantitative morphological description of an adult individual. This atlas serves as a reference model for comparative studies. Using isogenic medaka strains we show that comparative 3D morphometrics of individuals permits identification of quantitative strain-specific traits. Thus, our pipeline enables high resolution morphological analysis as a basis for genotype-phenotype association studies of complex genetic traits in vertebrates.
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27
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Willemink MJ, Noël PB. The evolution of image reconstruction for CT-from filtered back projection to artificial intelligence. Eur Radiol 2018; 29:2185-2195. [PMID: 30377791 PMCID: PMC6443602 DOI: 10.1007/s00330-018-5810-7] [Citation(s) in RCA: 261] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 09/12/2018] [Accepted: 09/27/2018] [Indexed: 12/22/2022]
Abstract
Abstract The first CT scanners in the early 1970s already used iterative reconstruction algorithms; however, lack of computational power prevented their clinical use. In fact, it took until 2009 for the first iterative reconstruction algorithms to come commercially available and replace conventional filtered back projection. Since then, this technique has caused a true hype in the field of radiology. Within a few years, all major CT vendors introduced iterative reconstruction algorithms for clinical routine, which evolved rapidly into increasingly advanced reconstruction algorithms. The complexity of algorithms ranges from hybrid-, model-based to fully iterative algorithms. As a result, the number of scientific publications on this topic has skyrocketed over the last decade. But what exactly has this technology brought us so far? And what can we expect from future hardware as well as software developments, such as photon-counting CT and artificial intelligence? This paper will try answer those questions by taking a concise look at the overall evolution of CT image reconstruction and its clinical implementations. Subsequently, we will give a prospect towards future developments in this domain. Key Points • Advanced CT reconstruction methods are indispensable in the current clinical setting. • IR is essential for photon-counting CT, phase-contrast CT, and dark-field CT. • Artificial intelligence will potentially further increase the performance of reconstruction methods.
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Affiliation(s)
- Martin J Willemink
- Department of Radiology, Stanford University School of Medicine, 300 Pasteur Drive, Room M-039, Stanford, CA, 94305-5105, USA. .,Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands.
| | - Peter B Noël
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Diagnostic and Interventional Radiology, Technische Universität München, Munich, Germany
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28
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Birnbacher L, Maurer S, Scheidt K, Herzen J, Pfeiffer F, Fromme T. Electron Density of Adipose Tissues Determined by Phase-Contrast Computed Tomography Provides a Measure for Mitochondrial Density and Fat Content. Front Physiol 2018; 9:707. [PMID: 29962958 PMCID: PMC6013718 DOI: 10.3389/fphys.2018.00707] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/22/2018] [Indexed: 11/13/2022] Open
Abstract
Phase-contrast computed tomography (PCCT) is an X-ray-based imaging method measuring differences in the refractive index during tissue passage. While conventional X-ray techniques rely on the absorption of radiation due to differing tissue-specific attenuation coefficients, PCCT enables the determination of the electron density (ED). By the analysis of respective phantoms and ex vivo specimens, we identified the components responsible for different electron densities in murine adipose tissue depots to be cellular fat and mitochondrial content, two parameters typically different between white adipose tissue (WAT) and brown adipose tissue (BAT). Brown adipocytes provide mammals with a means of non-shivering thermogenesis to defend normothermia in a cold environment. Brown adipocytes are found in dedicated BAT depots and interspersed within white fat depots, a cell type referred to as brite (brown in white) adipocyte. Localization and quantification of brown and brite adipocytes in situ allows an estimate of depot thermogenic capacity and potential contribution to maximal metabolic rate in the cold. We utilized PCCT to infer the composition of white, brite, and brown adipose tissue from ED of individual depots. As proof of principle, we imaged mice 10, 20, and 30 days of age. During this period, several WAT depots are known to undergo transient browning. Based on ED, classical WAT and BAT could be clearly distinguished. Retroperitoneal and inguinal WAT depots increased transiently in ED during the known remodeling from white to brite/brown and back to white. We systematically analyzed 18 anatomically defined adipose tissue locations and identified changes in fat content and mitochondrial density that imply an orchestrated pattern of simultaneous browning and whitening on the organismic level. Taken together, PCCT provides a three-dimensional imaging technique to visualize ED of tissues in situ. Within the adipose organ, ED provides a measure of mitochondrial density and fat content. Depending on experimental setting, these constitute surrogate markers of cellular distribution of white, brite, and brown adipocytes and thereby an estimate of thermogenic capacity.
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Affiliation(s)
- Lorenz Birnbacher
- Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Munich, Germany
| | - Stefanie Maurer
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Munich, Germany.,Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Freising, Germany
| | - Katharina Scheidt
- Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Munich, Germany
| | - Julia Herzen
- Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Munich, Germany
| | - Franz Pfeiffer
- Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, Munich, Germany.,Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany.,Institute for Advanced Study, Technical University of Munich, Munich, Germany
| | - Tobias Fromme
- Chair of Molecular Nutritional Medicine, TUM School of Life Sciences, Technical University of Munich, Munich, Germany.,Else Kröner-Fresenius Center for Nutritional Medicine, Technical University of Munich, Freising, Germany
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29
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Implementation of a Talbot-Lau interferometer in a clinical-like c-arm setup: A feasibility study. Sci Rep 2018; 8:2325. [PMID: 29396417 PMCID: PMC5797080 DOI: 10.1038/s41598-018-19482-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 01/02/2018] [Indexed: 02/07/2023] Open
Abstract
X-ray grating-based phase-contrast imaging has raised interest regarding a variety of potential clinical applications, whereas the method is feasible using a medical x-ray tube. Yet, the transition towards a clinical setup remains challenging due to the requirement of mechanical robustness of the interferometer and high demands applying to medical equipment in clinical use. We demonstrate the successful implementation of a Talbot-Lau interferometer in an interventional c-arm setup. The consequence of vibrations induced by the rotating anode of the tube is discussed and the prototype is shown to provide a visibility of 21.4% at a tube voltage of 60 kV despite the vibrations. Regarding clinical application, the prototype is mainly set back due to the limited size of the field of view covering an area of 17 mm × 46 mm. A c-arm offers the possibility to change the optical axis according to the requirements of the medical examination. We provide a method to correct for artifacts that result from the angulation of the c-arm. Finally, the images of a series of measurements with the c-arm in different angulated positions are shown. Thereby, it is sufficient to perform a single reference measurement in parking position that is valid for the complete series despite angulation.
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Pfeiffer F, Reiser M, Rummeny E. [X‑ray Phase Contrast : Principles, potential and advances in clinical translation]. Radiologe 2018; 58:218-225. [PMID: 29374312 DOI: 10.1007/s00117-018-0357-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
More than 100 years ago Max von Laue in Munich discovered that X‑rays can be interpreted not only as X‑ray quanta in a particle picture, but also show a wave character. This property has been used for a long time in basic research (e.g. in crystallography for determining the structure of proteins), but so far has had no application in medical imaging. In the last 10 years, however, very impressive technological progress could be made in preclinical research, which also makes the utilization of the wave character of X‑ray light possible for medical imaging. These novel radiography procedures, so-called phase-contrast and dark-field imaging, have a great potential for a pronounced improvement in X‑ray imaging and therefore, also the diagnosis of important diseases. This article describes the basic principles of these novel procedures, summarizes the preclinical research results already achieved exemplified by various organs and shows the potential for future clinical utilization in radiography and computed tomography.
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Affiliation(s)
- F Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Department Physik & Munich School of BioEngineering, Technische Universität München, München, Deutschland. .,Institut für diagnostische und interventionelle Radiologie, Klinikum rechts der Isar, Technische Universität München, München, Deutschland.
| | - M Reiser
- Klinik und Poliklinik für Radiologie, Klinikum der Universität, Ludwig-Maximilians-Universität München, München, Deutschland
| | - E Rummeny
- Institut für diagnostische und interventionelle Radiologie, Klinikum rechts der Isar, Technische Universität München, München, Deutschland
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31
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Braig EM, Birnbacher L, Schaff F, Gromann L, Fingerle A, Herzen J, Rummeny E, Noël P, Pfeiffer F, Muenzel D. Simultaneous wood and metal particle detection on dark-field radiography. Eur Radiol Exp 2018; 2:1. [PMID: 29708215 PMCID: PMC5909361 DOI: 10.1186/s41747-017-0034-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 11/28/2017] [Indexed: 11/23/2022] Open
Abstract
Background Currently, the detection of retained wood is a frequent but challenging task in emergency care. The purpose of this study is to demonstrate improved foreign-body detection with the novel approach of preclinical X-ray dark-field radiography. Methods At a preclinical dark-field x-ray radiography, setup resolution and sensitivity for simultaneous detection of wooden and metallic particles have been evaluated in a phantom study. A clinical setting has been simulated with a formalin fixated human hand where different typical foreign-body materials have been inserted. Signal-to-noise ratios (SNR) have been determined for all test objects. Results On the phantom, the SNR value for wood in the dark-field channel was strongly improved by a factor 6 compared to conventional radiography and even compared to the SNR of an aluminium structure of the same size in conventional radiography. Splinters of wood < 300 μm in diameter were clearly detected on the dark-field radiography. Dark-field radiography of the formalin-fixated human hand showed a clear signal for wooden particles that could not be identified on conventional radiography. Conclusions x-ray dark-field radiography enables the simultaneous detection of wooden and metallic particles in the extremities. It has the potential to improve and simplify the current state-of-the-art foreign-body detection.
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Affiliation(s)
- Eva-Maria Braig
- 1Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany.,2Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675 München, Germany
| | - Lorenz Birnbacher
- 1Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Florian Schaff
- 1Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Lukas Gromann
- 1Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Alexander Fingerle
- 2Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675 München, Germany
| | - Julia Herzen
- 1Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany
| | - Ernst Rummeny
- 2Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675 München, Germany
| | - Peter Noël
- 1Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany.,2Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675 München, Germany
| | - Franz Pfeiffer
- 1Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, James-Franck-Str. 1, 85748 Garching, Germany.,2Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675 München, Germany.,3Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany
| | - Daniela Muenzel
- 2Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Straße 22, 81675 München, Germany
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32
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Ex Vivo Assessment of Coronary Atherosclerotic Plaque by Grating-Based Phase-Contrast Computed Tomography: Correlation With Optical Coherence Tomography. Invest Radiol 2017; 52:223-231. [PMID: 28079701 DOI: 10.1097/rli.0000000000000346] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The aim of this study was to determine the diagnostic accuracy of grating-based phase-contrast computed tomography (gb-PCCT) to classify and quantify coronary vessel characteristics in comparison with optical coherence tomography (OCT) and histopathology in an ex vivo setting. MATERIALS AND METHODS After excision from 5 heart specimens, 15 human coronary arteries underwent gb-PCCT examination using an experimental imaging setup consisting of a rotating molybdenum anode x-ray tube, a Talbot-Lau grating interferometer, and a single photon counting detector. Subsequently, all vessels were imaged by OCT and histopathologically processed. Optical coherence tomography, gb-PCCT, and histopathology images were manually matched using anatomical landmarks. Optical coherence tomography and gb-PCCT were reviewed by 2 independent observers blinded to histopathology. Vessel, lumen, and plaque area were measured, and plaque characteristics (lipid rich, calcified, and fibrous) were determined for each section. Measures of diagnostic accuracy were derived, applying histopathology as the standard of reference. RESULTS Of a total of 286 assessed cross sections, 241 corresponding sections were included in the statistical analysis. Quantitative measures derived from gb-PCCT were significantly higher than from OCT (P < 0.001) and were strongly correlated with histopathology (Pearson r ≥0.85 for gb-PCCT and ≥0.61 for OCT, respectively). Results of Bland-Altman analysis demonstrated smaller mean differences between OCT and histopathology than for gb-PCCT and histopathology. Limits of agreement were narrower for gb-PCCT with regard to lumen area, for OCT with regard to plaque area, and were comparable with regard to vessel area. Based on histopathology, 228/241 (94.6%) sections were classified as fibrous, calcified, or lipid rich. The diagnostic accuracy of gb-PCCT was excellent for the detection of all plaque components (sensitivity, ≥0.95; specificity, ≥0.94), whereas the results for OCT showed sensitivities of ≥0.73 and specificities of ≥0.66. CONCLUSIONS In this ex vivo setting, gb-PCCT provides excellent results in the assessment of coronary atherosclerotic plaque characteristics and vessel dimensions in comparison to OCT and histopathology. Thus, the technique may serve as adjunct nondestructive modality for advanced plaque characterization in an experimental setting.
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33
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Georgiadis M, Müller R, Schneider P. Techniques to assess bone ultrastructure organization: orientation and arrangement of mineralized collagen fibrils. J R Soc Interface 2017; 13:rsif.2016.0088. [PMID: 27335222 DOI: 10.1098/rsif.2016.0088] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 05/18/2016] [Indexed: 12/13/2022] Open
Abstract
Bone's remarkable mechanical properties are a result of its hierarchical structure. The mineralized collagen fibrils, made up of collagen fibrils and crystal platelets, are bone's building blocks at an ultrastructural level. The organization of bone's ultrastructure with respect to the orientation and arrangement of mineralized collagen fibrils has been the matter of numerous studies based on a variety of imaging techniques in the past decades. These techniques either exploit physical principles, such as polarization, diffraction or scattering to examine bone ultrastructure orientation and arrangement, or directly image the fibrils at the sub-micrometre scale. They make use of diverse probes such as visible light, X-rays and electrons at different scales, from centimetres down to nanometres. They allow imaging of bone sections or surfaces in two dimensions or investigating bone tissue truly in three dimensions, in vivo or ex vivo, and sometimes in combination with in situ mechanical experiments. The purpose of this review is to summarize and discuss this broad range of imaging techniques and the different modalities of their use, in order to discuss their advantages and limitations for the assessment of bone ultrastructure organization with respect to the orientation and arrangement of mineralized collagen fibrils.
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Affiliation(s)
| | - Ralph Müller
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Philipp Schneider
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland Bioengineering Science Research Group, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK
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34
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Marschner M, Birnbacher L, Willner M, Chabior M, Herzen J, Noël PB, Pfeiffer F. Revising the lower statistical limit of x-ray grating-based phase-contrast computed tomography. PLoS One 2017; 12:e0184217. [PMID: 28877253 PMCID: PMC5587302 DOI: 10.1371/journal.pone.0184217] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 08/21/2017] [Indexed: 11/18/2022] Open
Abstract
Phase-contrast x-ray computed tomography (PCCT) is currently investigated as an interesting extension of conventional CT, providing high soft-tissue contrast even if examining weakly absorbing specimen. Until now, the potential for dose reduction was thought to be limited compared to attenuation CT, since meaningful phase retrieval fails for scans with very low photon counts when using the conventional phase retrieval method via phase stepping. In this work, we examine the statistical behaviour of the reverse projection method, an alternative phase retrieval approach and compare the results to the conventional phase retrieval technique. We investigate the noise levels in the projections as well as the image quality and quantitative accuracy of the reconstructed tomographic volumes. The results of our study show that this method performs better in a low-dose scenario than the conventional phase retrieval approach, resulting in lower noise levels, enhanced image quality and more accurate quantitative values. Overall, we demonstrate that the lower statistical limit of the phase stepping procedure as proposed by recent literature does not apply to this alternative phase retrieval technique. However, further development is necessary to overcome experimental challenges posed by this method which would enable mainstream or even clinical application of PCCT.
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Affiliation(s)
- Mathias Marschner
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
- * E-mail:
| | - Lorenz Birnbacher
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
| | - Marian Willner
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 München, Germany
| | - Michael Chabior
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
| | - Julia Herzen
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 München, Germany
| | - Peter B. Noël
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 München, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748 Garching, Germany
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675 München, Germany
- Institute for Advanced Study, Technical University of Munich, 85748 Garching, Germany
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35
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Grating-based phase-contrast and dark-field computed tomography: a single-shot method. Sci Rep 2017; 7:7476. [PMID: 28785015 PMCID: PMC5547164 DOI: 10.1038/s41598-017-06729-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 06/15/2017] [Indexed: 11/19/2022] Open
Abstract
Grating-based X-ray interferometry offers vast potential for imaging materials and tissues that are not easily visualised using conventional X-ray imaging. Tomographic reconstruction based on X-ray interferometric data provides not only access to the attenuation coefficient of an object, but also the refractive index and information about ultra-small-angle scattering. This improved functionality comes at the cost of longer measurement times because existing projection-based signal extraction algorithms require not only a single measurement per projection angle but several with precise grating movements in between. This obstacle hinders the adaptation of grating-based interferometry into a continuously rotating gantry. Several solutions to this problem have been proposed but all suffer from major drawbacks. We present results using an iterative reconstruction algorithm working directly on the interferograms. The suggested direct approach enables improved image quality, since interpolations and unnecessary assumptions about the object are circumvented. Our results demonstrate that it is possible to successfully reconstruct the linear attenuation coefficient, the refractive index and the linear diffusion coefficient, which is a measure related to ultra-small-angle scattering, using a single measurement per projection angle and without any grating movements. This is a milestone for future clinical implementation of grating-based phase-contrast and dark-field contrast X-ray computed tomography.
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36
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Roth CJ, Yoshihara L, Wall WA. A simplified parametrised model for lung microstructures capable of mimicking realistic geometrical and mechanical properties. Comput Biol Med 2017; 89:104-114. [PMID: 28800439 DOI: 10.1016/j.compbiomed.2017.07.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 07/27/2017] [Accepted: 07/28/2017] [Indexed: 11/16/2022]
Abstract
The respiratory zone of mammalian lungs contains several millions of so-called alveoli. The geometrical and mechanical properties of this microstructure are crucial for respiration and influence the macroscopic behaviour of the entire organ in health and disease. Hence, if computational models are sought to gain more insight into lung behaviour, predict lung states in certain scenarios or suggest better treatment options in early stages of respiratory dysfunction, an adequate representation of this microstructure is essential. However, investigating the real alveolar architecture requires complex medical-imaging methods and would be computationally extremely expensive. Even worse, there is currently no way of obtaining the real patient-specific microstructure in vivo. Hence, we present a fast and easy to compute parametrised model of lung microstructures based on tetrakaidecahedra which can represent both geometrical and mechanical properties of the parenchyma. We show that gas transport pathways and stress and strain distributions are comparable to real alveolar microstructures and even capable of capturing variations present in biology. The created parametrised lung microstructure models can be utilized in finite element simulations to study, e.g., alveolar flow phenomena, particle deposition, or alveolar stresses and strains during mechanical ventilation. Due to the simpler geometry of the parametrised microgeometries compared to imaging-based microstructures, remarkable savings in CPU time can be achieved. We show that our model requires a minimum of 10% of the computational time for computing the same strain state in structural mechanics simulations compared to imaging-based alveolar microstructures.
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Affiliation(s)
- Christian J Roth
- Institute for Computational Mechanics, Technical University of Munich, Boltzmannstrasse 15, 85748, Garching b. München, Germany
| | - Lena Yoshihara
- Institute for Computational Mechanics, Technical University of Munich, Boltzmannstrasse 15, 85748, Garching b. München, Germany.
| | - Wolfgang A Wall
- Institute for Computational Mechanics, Technical University of Munich, Boltzmannstrasse 15, 85748, Garching b. München, Germany
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37
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Astolfo A, Endrizzi M, Vittoria FA, Diemoz PC, Price B, Haig I, Olivo A. Large field of view, fast and low dose multimodal phase-contrast imaging at high x-ray energy. Sci Rep 2017; 7:2187. [PMID: 28526835 PMCID: PMC5438381 DOI: 10.1038/s41598-017-02412-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 04/12/2017] [Indexed: 12/13/2022] Open
Abstract
X-ray phase contrast imaging (XPCI) is an innovative imaging technique which extends the contrast capabilities of 'conventional' absorption based x-ray systems. However, so far all XPCI implementations have suffered from one or more of the following limitations: low x-ray energies, small field of view (FOV) and long acquisition times. Those limitations relegated XPCI to a 'research-only' technique with an uncertain future in terms of large scale, high impact applications. We recently succeeded in designing, realizing and testing an XPCI system, which achieves significant steps toward simultaneously overcoming these limitations. Our system combines, for the first time, large FOV, high energy and fast scanning. Importantly, it is capable of providing high image quality at low x-ray doses, compatible with or even below those currently used in medical imaging. This extends the use of XPCI to areas which were unpractical or even inaccessible to previous XPCI solutions. We expect this will enable a long overdue translation into application fields such as security screening, industrial inspections and large FOV medical radiography - all with the inherent advantages of the XPCI multimodality.
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Affiliation(s)
- Alberto Astolfo
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, Gower Street, London, United Kingdom.
| | - Marco Endrizzi
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, Gower Street, London, United Kingdom
| | - Fabio A Vittoria
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, Gower Street, London, United Kingdom
| | - Paul C Diemoz
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, Gower Street, London, United Kingdom
| | - Benjamin Price
- X-Tek Systems-Nikon, Tring Business Centre, Icknield Way, Tring, Hertfordshire, UK
| | - Ian Haig
- X-Tek Systems-Nikon, Tring Business Centre, Icknield Way, Tring, Hertfordshire, UK
| | - Alessandro Olivo
- Department of Medical Physics and Biomedical Engineering, University College London, Malet Place, Gower Street, London, United Kingdom.
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38
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Scherer K, Yaroshenko A, Bölükbas DA, Gromann LB, Hellbach K, Meinel FG, Braunagel M, Berg JV, Eickelberg O, Reiser MF, Pfeiffer F, Meiners S, Herzen J. X-ray Dark-field Radiography - In-Vivo Diagnosis of Lung Cancer in Mice. Sci Rep 2017; 7:402. [PMID: 28341830 PMCID: PMC5428469 DOI: 10.1038/s41598-017-00489-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 02/28/2017] [Indexed: 02/01/2023] Open
Abstract
Accounting for about 1.5 million deaths annually, lung cancer is the prevailing cause of cancer deaths worldwide, mostly associated with long-term smoking effects. Numerous small-animal studies are performed currently in order to better understand the pathogenesis of the disease and to develop treatment strategies. Within this letter, we propose to exploit X-ray dark-field imaging as a novel diagnostic tool for the detection of lung cancer on projection radiographs. Here, we demonstrate in living mice bearing lung tumors, that X-ray dark-field radiography provides significantly improved lung tumor detection rates without increasing the number of false-positives, especially in the case of small and superimposed nodules, when compared to conventional absorption-based imaging. While this method still needs to be adapted to larger mammals and finally humans, the technique presented here can already serve as a valuable tool in evaluating novel lung cancer therapies, tested in mice and other small animal models.
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Affiliation(s)
- Kai Scherer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany.
| | - Andre Yaroshenko
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany
- Philips Medical Systems DMC GmbH, 22335, Hamburg, Germany
| | - Deniz Ali Bölükbas
- Comprehensive Pneumology Center (CPC), University Hospital, Ludwig-Maximilians University, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Lukas B Gromann
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany
| | - Katharina Hellbach
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377, Munich, Germany
| | - Felix G Meinel
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377, Munich, Germany
| | - Margarita Braunagel
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377, Munich, Germany
| | - Jens von Berg
- Philips Research Laboratories, Philips Medical Systems, 22335, Hamburg, Germany
| | - Oliver Eickelberg
- Comprehensive Pneumology Center (CPC), University Hospital, Ludwig-Maximilians University, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Maximilian F Reiser
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377, Munich, Germany
| | - Franz Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany
| | - Silke Meiners
- Comprehensive Pneumology Center (CPC), University Hospital, Ludwig-Maximilians University, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Julia Herzen
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany
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39
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Yaroshenko A, Pritzke T, Koschlig M, Kamgari N, Willer K, Gromann L, Auweter S, Hellbach K, Reiser M, Eickelberg O, Pfeiffer F, Hilgendorff A. Visualization of neonatal lung injury associated with mechanical ventilation using x-ray dark-field radiography. Sci Rep 2016; 6:24269. [PMID: 27072871 PMCID: PMC4829826 DOI: 10.1038/srep24269] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 03/23/2016] [Indexed: 02/01/2023] Open
Abstract
Mechanical ventilation (MV) and supplementation of oxygen-enriched gas, often needed in postnatal resuscitation procedures, are known to be main risk factors for impaired pulmonary development in the preterm and term neonates. Unfortunately, current imaging modalities lack in sensitivity for the detection of early stage lung injury. The present study reports a new imaging approach for diagnosis and staging of early lung injury induced by MV and hyperoxia in neonatal mice. The imaging method is based on the Talbot-Lau x-ray grating interferometry that makes it possible to quantify the x-ray small-angle scattering on the air-tissue interfaces. This so-called dark-field signal revealed increasing loss of x-ray small-angle scattering when comparing images of neonatal mice undergoing hyperoxia and MV-O2 with animals kept at room air. The changes in the dark field correlated well with histologic findings and provided superior differentiation than conventional x-ray imaging and lung function testing. The results suggest that x-ray dark-field radiography is a sensitive tool for assessing structural changes in the developing lung. In the future, with further technical developments x-ray dark-field imaging could be an important tool for earlier diagnosis and sensitive monitoring of lung injury in neonates requiring postnatal oxygen or ventilator therapy.
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Affiliation(s)
- Andre Yaroshenko
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - Tina Pritzke
- Comprehensive Pneumology Center, Helmholtz Zentrum Muenchen, Munich, Germany, Member of the German Center for Lung Research (DZL)
| | - Markus Koschlig
- Comprehensive Pneumology Center, Helmholtz Zentrum Muenchen, Munich, Germany, Member of the German Center for Lung Research (DZL)
| | - Nona Kamgari
- Comprehensive Pneumology Center, Helmholtz Zentrum Muenchen, Munich, Germany, Member of the German Center for Lung Research (DZL)
| | - Konstantin Willer
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - Lukas Gromann
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - Sigrid Auweter
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich
| | - Katharina Hellbach
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich
| | - Maximilian Reiser
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich
| | - Oliver Eickelberg
- Comprehensive Pneumology Center, Helmholtz Zentrum Muenchen, Munich, Germany, Member of the German Center for Lung Research (DZL)
| | - Franz Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Physik-Department &Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - Anne Hilgendorff
- Comprehensive Pneumology Center, Helmholtz Zentrum Muenchen, Munich, Germany, Member of the German Center for Lung Research (DZL).,Department of Neonatology, Perinatal Center, Dr. von Haunersches Children's Hospital, Ludwig-Maximilians University, Munich, Germany
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40
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Wolf J, Sperl JI, Schaff F, Schüttler M, Yaroshenko A, Zanette I, Herzen J, Pfeiffer F. Lens-term- and edge-effect in X-ray grating interferometry. BIOMEDICAL OPTICS EXPRESS 2015; 6:4812-4824. [PMID: 26713196 PMCID: PMC4679256 DOI: 10.1364/boe.6.004812] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/15/2015] [Accepted: 10/15/2015] [Indexed: 06/05/2023]
Abstract
X-ray grating interferometry requires gratings with periods in the micrometer range and allows the acquisition of the dark-field contrast. The analyzer grating is designed to match the period of the interference pattern in order to translate it into a measurable intensity modulation. In this study, we explore the influence of a sample-induced mismatch between the interference pattern and the analyzer grating on the dark-field contrast. We propose a formula for the calculation of the signal due to a period mismatch and present estimations varying periods and detector pixel size. Furthermore, numerical simulations of the X-ray wave-front demonstrate that the wave-front curvature, described by the lens-term, e.g. behind a parabolic lens or edges of a sample can change the period of the interference pattern. Our results give a concrete explanation for the formation of a dark-field contrast from object edges and thus allow a better understanding of the dark-field signal obtained with a grating interferometer.
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Affiliation(s)
- Johannes Wolf
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching,
Germany
| | | | - Florian Schaff
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching,
Germany
| | - Markus Schüttler
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching,
Germany
| | - Andre Yaroshenko
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching,
Germany
| | - Irene Zanette
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching,
Germany
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE,
UK
| | - Julia Herzen
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching,
Germany
| | - Franz Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748 Garching,
Germany
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41
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Ritman EL. In vivo X-Ray Phase Imaging. EBioMedicine 2015; 2:1304-5. [PMID: 26629520 PMCID: PMC4634695 DOI: 10.1016/j.ebiom.2015.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 09/04/2015] [Indexed: 12/02/2022] Open
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