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40 results on '"SAVVIDIS, SAVVAS"'

2. Single-shot X-ray Dark-field Tomography

Author

Doherty, Adam, Buchanan, Ian, Astolfo, Alberto, Savvidis, Savvas, Gerli, Mattia F. M., Citro, Antonio, Olivo, Alessandro, and Endrizzi, Marco

Subjects
Physics - Medical Physics, Physics - Optics
Abstract

X-ray dark-field imaging creates a representation of the sample where contrast is generated by subresolution features within the volume under inspection. These are detected by a local measurement of the radiation field's angular distribution, and how it is affected by the interaction with matter. X-ray dark-field imaging typically requires taking multiple exposures for separating the contributions to the detected X-ray intensity arising from scattering, refraction and attenuation; a procedure often called phase retrieval. We propose an approach to retrieve an X-ray dark-field image from a single X-ray shot. We demonstrate the method using a laboratory-based, rotating anode X-ray tube system without the need for coherent radiation or a high-resolution detector. This reduces the complexity of data acquisition, enabling faster scanning and increasing dose efficiency. Moreover, our approach reduces the problem dimensionality by one, with substantial implications for data-intensive applications like tomography. The model assumes a homogeneous material, and we show this is a valid hypothesis for soft biological tissues by reconstructing dark-field tomography images from data sets containing a single shot per view. We believe our method to be broadly applicable and relevant for many X-ray dark-field imaging implementations, including fast radiography, directional dark-field and for use with pulsed X-ray sources., Comment: 7 pages, 3 figures with additional supplemental material of 3 pages, 3 figures

Published
2023

3. Author Correction: Single-cell guided prenatal derivation of primary fetal epithelial organoids from human amniotic and tracheal fluids

Author

Gerli, Mattia Francesco Maria, Calà, Giuseppe, Beesley, Max Arran, Sina, Beatrice, Tullie, Lucinda, Sun, Kylin Yunyan, Panariello, Francesco, Michielin, Federica, Davidson, Joseph R., Russo, Francesca Maria, Jones, Brendan C., Lee, Dani Do Hyang, Savvidis, Savvas, Xenakis, Theodoros, Simcock, Ian C., Straatman-Iwanowska, Anna A., Hirst, Robert A., David, Anna L., O’Callaghan, Christopher, Olivo, Alessandro, Eaton, Simon, Loukogeorgakis, Stavros P., Cacchiarelli, Davide, Deprest, Jan, Li, Vivian S. W., Giobbe, Giovanni Giuseppe, and De Coppi, Paolo

Published
2025
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4. X-ray phase-contrast micro tomography of soft tissues using a compact laboratory system with two-directional sensitivity

Author

Navarrete-Leon, Carlos, Doherty, Adam, Savvidis, Savvas, Gerli, Mattia F. M., Piredda, Giovanni, Astolfo, Alberto, Cipiccia, Silvia, Bate, David, Hagen, Charlotte K., Olivo, Alessandro, and Endrizzi, Marco

Subjects
Physics - Instrumentation and Detectors
Abstract

X-ray micro tomography is a non-destructive, 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 micro tomography to classes of samples that exhibit weak attenuation, thus appear with poor contrast in standard X-ray imaging. Notable examples are low-atomic-number materials, like carbon-fibre composites, soft matter and biological soft tissues. We report on a compact and cost effective system for X-ray phase-contrast micro tomography. 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: single-photon-counting offers higher sensitivity whereas flat-panels are preferred for 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 oesophagus and a rat heart.

Published
2022

5. Single-cell guided prenatal derivation of primary fetal epithelial organoids from human amniotic and tracheal fluids

Author

Gerli, Mattia Francesco Maria, Calà, Giuseppe, Beesley, Max Arran, Sina, Beatrice, Tullie, Lucinda, Sun, Kylin Yunyan, Panariello, Francesco, Michielin, Federica, Davidson, Joseph R., Russo, Francesca Maria, Jones, Brendan C., Lee, Dani Do Hyang, Savvidis, Savvas, Xenakis, Theodoros, Simcock, Ian C., Straatman-Iwanowska, Anna A., Hirst, Robert A., David, Anna L., O’Callaghan, Christopher, Olivo, Alessandro, Eaton, Simon, Loukogeorgakis, Stavros P., Cacchiarelli, Davide, Deprest, Jan, Li, Vivian S. W., Giobbe, Giovanni Giuseppe, and De Coppi, Paolo

Published
2024
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8. X-ray phase-contrast microtomography of soft tissues using a compact laboratory system with two-directional sensitivity

Author

Navarrete-León, Carlos, primary, Doherty, Adam, additional, Savvidis, Savvas, additional, Gerli, Mattia F. M., additional, Piredda, Giovanni, additional, Astolfo, Alberto, additional, Bate, David, additional, Cipiccia, Silvia, additional, Hagen, Charlotte K., additional, Olivo, Alessandro, additional, and Endrizzi, Marco, additional

Published
2023
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11. Advanced x-ray imaging techniques in tissue engineering: a new construct assessment platform for enabling the regeneration of personalised organs

Author

Savvidis, Savvas, primary, Gerli, Mattia F., additional, Citro, Antonio, additional, Massimi, Lorenzo, additional, Hagen, Charlotte K., additional, Endrizzi, Marco, additional, Atzeni, Alessia, additional, Astolfo, Alberto, additional, Esposito, Michela, additional, Ogunbiyi, Olumide K., additional, Turmaine, Mark, additional, Smith, Elizabeth S., additional, Cipiccia, Silvia, additional, Rau, Christoph, additional, Li, Peng, additional, Lutman, Roberto, additional, Selmin, Giulia, additional, Durkin, Natalie, additional, Shibuya, Soichi, additional, Scuglia, Marianna, additional, Pellegrini, Marco, additional, De Coppi, Paolo, additional, and Olivo, Alessandro, additional

Published
2023
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13. Technical note: Cartilage imaging with sub‐cellular resolution using a laboratory‐based phase‐contrast x‐ray microscope.

Author

Esposito, Michela, Astolfo, Alberto, Cipiccia, Silvia, Jones, Charlotte Maughan, Savvidis, Savvas, Ferrara, Joseph D., Endrizzi, Marco, Dudhia, Jayesh, and Olivo, Alessandro

Subjects
MICROSCOPES, X-rays, ENDOCHONDRAL ossification, X-ray imaging, CARTILAGE, CARTILAGE cells, CELL imaging
Abstract

Background: Microscopic imaging of cartilage is a key tool for the study and development of treatments for osteoarthritis. When cellular and sub‐cellular resolution is required, histology remains the gold standard approach, albeit limited by the lack of volumetric information as well as by processing artifacts. Cartilage imaging with the sub‐cellular resolution has only been demonstrated in the synchrotron environment. Purpose: To provide a proof‐of‐concept demonstration of the capability of a laboratory‐based x‐ray phase‐contrast microscope to resolve sub‐cellular features in a cartilage sample. Methods: This work is based on a laboratory‐based x‐ray microscope using intensity‐modulation masks. The structured nature of the beam, resulting from the mask apertures, allows the retrieval of three contrast channels, namely, transmission, refraction and dark‐field, with resolution depending only on the mask aperture width. An ex vivo equine cartilage sample was imaged with the x‐ray microscope and results were validated with synchrotron tomography and histology. Results: Individual chondrocytes, that is, cells responsible for cartilage formation, could be detected with the laboratory‐based microscope. The complementarity of the three retrieved contrast channels allowed the detection of sub‐cellular features in the chondrocytes. Conclusions: We provide the first proof‐of‐concept of imaging cartilage tissue with sub‐cellular resolution using a laboratory‐based x‐ray microscope. [ABSTRACT FROM AUTHOR]

Published
2023
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15. Intra-operative assessment of cancer with x-ray phase contrast computed tomography

Author

Partridge, Thomas, primary, Massimi, Lorenzo, additional, Wolfson, Paul, additional, Jiang, Jinxing, additional, Astolfo, Alberto, additional, Suaris, Tamara, additional, Havariyoun, Glafkos, additional, Savvidis, Savvas, additional, Maughan Jones, Charlotte J., additional, Djurabekova, Nargiza, additional, Hawker, Sam P. M., additional, Smit, Bennie, additional, Larkin, Oliver J., additional, Millard, Edward, additional, Shorrock, Wilf, additional, Waltham, Richard, additional, Ho, Kai Man Alexander, additional, McBain, Hazel, additional, Wilson, Ash, additional, Peel, Anthony, additional, Shah, Zoheb, additional, Nelan, Rachel L., additional, Delaney, Harry, additional, Liyadipita, Ama, additional, Lavine, Adam P., additional, Dawas, Khaled, additional, Mohammadi, Borzoueh, additional, Qureshi, Yassar, additional, Chouhan, Manil D., additional, Taylor, Stuart A., additional, Mughal, Muntzer, additional, Endrizzi, Marco, additional, Hagen, Charlotte K., additional, Munro, Peter R. T., additional, Duffy, Stephen W., additional, Jones, Louise J., additional, Novelli, Marco, additional, Lovat, Laurence B., additional, Haig, Ian G., additional, Bate, David, additional, and Olivo, Alessando, additional

Published
2022
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16. Advanced x-ray imaging techniques in tissue engineering: a new construct assessment platform for enabling the regeneration of personalised organs

Author

Gimi, Barjor S., Krol, Andrzej, Savvidis, Savvas, Gerli, Mattia F. M., Citro, Antonio, Massimi, Lorenzo, Hagen, Charlotte K., Endrizzi, Marco, Atzeni, Alessia, Astolfo, Alberto, Esposito, Michela, Ogunbiyi, Olumide K., Turmaine, Mark, Smith, Elizabeth S., Cipiccia, Silvia, Rau, Christoph, Li, Peng, Lutman, Roberto, Selmin, Giulia, Durkin, Natalie, Shibuya, Soichi, Scuglia, Marianna, Pellegrini, Marco, De Coppi, Paolo, and Olivo, Alessandro

Published
2023
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18. Exploring the potential of cycloidal computed tomography for advancing intraoperative specimen imaging

Author

Roche i Morgo, Oriol, primary, Massimi, Lorenzo, additional, Suaris, Tamara, additional, Endrizzi, Marco, additional, Munro, Peter, additional, Savvidis, Savvas, additional, Havariyoun, Glafcos, additional, Hawker, P. M. Sam, additional, Astolfo, Alberto, additional, Larkin, Oliver J., additional, Nelan, Rachel L., additional, Jones, J. Louise, additional, Pelt, Daniël M., additional, Bate, David, additional, Olivo, Alessandro, additional, and Hagen, Charlotte, additional

Published
2021
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31. Advanced x-ray imaging techniques in tissue engineering: a new construct assessment platform for enabling the regeneration of personalised organs.

Author

Savvidis, Savvas, Gerli, Mattia F. M., Citro, Antonio, Massimi, Lorenzo, Hagen, Charlotte K., Endrizzi, Marco, Atzeni, Alessia, Astolfo, Alberto, Esposito, Michela, Ogunbiyi, Olumide K., Turmaine, Mark, Smith, Elizabeth S., Cipiccia, Silvia, Rau, Christoph, Li, Peng, Lutman, Roberto, Selmin, Giulia, Durkin, Natalie, Shibuya, Soichi, and Scuglia, Marianna

Published
2023
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36. Environmental Indexes and Financial Ratios in SME.

Author

Savvidis, Savvas and Ginoglou, Dimitrios

Subjects
*ACCOUNTING, *BUSINESS enterprises, *FINANCIAL ratios, *ENVIRONMENTAL indicators, *SOCIAL responsibility of business, *SMALL business
Abstract

To date, accounting and financial sciences have attempted to assess companies using financial ratios and other techniques that evaluate only the front office, without considering its impact to the environment. Recently, this assessment has been expanded to include new concepts, known as corporate social responsibility and social balance. These new concepts are usually viewed and studied using a multidisciplinary perspective with an aim to update the current and future value of the company. In this evolving scientific field a considerable effort has been made to objectively record and calculate the environmental impact of a company's activities by integrating these elements into a new form of economic balance sheet. The present paper seeks to examine the presence of weighted environmental indexes and explores the process by which they can be used to evaluate a company. [ABSTRACT FROM AUTHOR]

Published
2014

39. Hybrid dark-field and attenuation contrast retrieval for laboratory-based X-ray tomography.

Author

Doherty A, Buchanan I, Roche I Morgó O, Astolfo A, Savvidis S, Gerli MFM, Citro A, Olivo A, and Endrizzi M

Abstract

X-ray dark-field imaging highlights sample structures through contrast generated by sub-resolution features within the inspected volume. Quantifying dark-field signals generally involves multiple exposures for phase retrieval, separating contributions from scattering, refraction, and attenuation. Here, we introduce an approach for non-interferometric X-ray dark-field imaging that presents a single-parameter representation of the sample. This fuses attenuation and dark-field signals, enabling the reconstruction of a unified three-dimensional volume. Notably, our method can obtain dark-field contrast from a single exposure and employs conventional back projection algorithms for reconstruction. Our approach is based on the assumption of a macroscopically homogeneous material, which we validate through experiments on phantoms and on biological tissue samples. The methodology is implemented on a laboratory-based, rotating anode X-ray tube system without the need for coherent radiation or a high-resolution detector. Utilizing this system with streamlined data acquisition enables expedited scanning while maximizing dose efficiency. These attributes are crucial in time- and dose-sensitive medical imaging applications and unlock the ability of dark-field contrast with high-throughput lab-based tomography. We believe that the proposed approach can be extended across X-ray dark-field imaging implementations beyond tomography, spanning fast radiography, directional dark-field imaging, and compatibility with pulsed X-ray sources., Competing Interests: ME and AO declare a relevant patent: US granted US14/898281, Japan granted JP2016520736, and Europe granted EP 2014731991., (© 2024 The Author(s).)

Published
2024
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40. [77-year old man with dyspnea and acral cyanosis].

Author

Fröhlich G, Ferrari M, and Savvidis S

Subjects
Aged, Anticoagulants adverse effects, Chromosome Breakage, Diagnosis, Differential, Dyspnea diagnosis, Foot Diseases chemically induced, Foot Diseases diagnosis, Hand, Humans, Male, Thrombocytopenia chemically induced, Thrombocytopenia diagnosis, Chromosome Disorders chemically induced, Chromosome Disorders diagnosis, Cyanosis chemically induced, Cyanosis diagnosis, Dyspnea chemically induced, Heparin adverse effects, Thrombocytopenia congenital
Published
2016
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