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Publications (10 of 152) Show all publications
Twengström, W., Persson, J., Szekely, L. & Hertz, H. (2018). Cellular-resolution 3D virtual histology of human coronary arteries using x-ray phase tomography. Scientific Reports, 8, Article ID 11014.
Open this publication in new window or tab >>Cellular-resolution 3D virtual histology of human coronary arteries using x-ray phase tomography
2018 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 11014Article in journal (Refereed) Published
Abstract [en]

High-spatial-resolution histology of coronary artery autopsy samples play an important role for understanding heart disease such as myocardial infarction. Unfortunately, classical histology is often destructive, has thick slicing, requires extensive sample preparation, and is time-consuming. X-ray micro-CT provides fast nondestructive 3D imaging but absorption contrast is often insufficient, especially for observing soft-tissue features with high resolution. Here we show that propagation-based x-ray phase-contrast tomography has the resolution and contrast to image clinically relevant soft-tissue features in intact coronary artery autopsy samples with cellular resolution. We observe microscopic lipid-rich plaques, individual adipose cells, ensembles of few foam cells, and the thin fibrous cap. The method relies on a small-spot laboratory x-ray microfocus source, and provides high-spatial resolution in all three dimensions, fast data acquisition, minimum sample distortion and requires no sample preparation.

Place, publisher, year, edition, pages
Nature Publishing Group, 2018
National Category
Medical Image Processing
Identifiers
urn:nbn:se:kth:diva-232889 (URN)10.1038/s41598-018-29344-3 (DOI)000439278300049 ()30030461 (PubMedID)2-s2.0-85050531102 (Scopus ID)
Note

QC 20180809

Available from: 2018-08-09 Created: 2018-08-09 Last updated: 2018-09-06Bibliographically approved
Häggmark, I., Romell, J., Lewin, S., Öhman, C. & Hertz, H. (2018). Cellular-Resolution Imaging of Microstructures in Rat Bone using Laboratory Propagation-Based Phase-Contrast X-ray Tomography. In: Microscopy and Microanalysis: . Paper presented at 14th International Conference on X-ray Microscopy (pp. 368-369). , 24
Open this publication in new window or tab >>Cellular-Resolution Imaging of Microstructures in Rat Bone using Laboratory Propagation-Based Phase-Contrast X-ray Tomography
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2018 (English)In: Microscopy and Microanalysis, 2018, Vol. 24, p. 368-369Conference paper, Published paper (Refereed)
National Category
Medical Image Processing Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:kth:diva-240273 (URN)10.1017/S1431927618014137 (DOI)
Conference
14th International Conference on X-ray Microscopy
Note

QC 20181217

Available from: 2018-12-14 Created: 2018-12-14 Last updated: 2018-12-17Bibliographically approved
Larsson, J. C., Shaker, K. & Hertz, H. (2018). Focused anti-scatter grid for background reduction in x-ray fluorescence tomography. Optics Letters, 43(11), 2591-2594
Open this publication in new window or tab >>Focused anti-scatter grid for background reduction in x-ray fluorescence tomography
2018 (English)In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 43, no 11, p. 2591-2594Article in journal (Refereed) Published
Abstract [en]

X-ray fluorescence (XRF) tomography is an emerging imaging technology with the potential for high spatial resolution molecular imaging. One of the key limitations is the background noise due to Compton scattering since it degrades the signal and limits the sensitivity. In this Letter, we present a linear focused anti-scatter grid that reduces the Compton scattering background. An anti-scatter grid was manufactured and evaluated both experimentally and theoretically with Monte Carlo simulations. The measurements showed a 31% increase in signal-to-background ratio, and simulations of an improved grid showed that this can easily be extended up to > 75%. Simulated tomographies using the improved grid show a large improvement in reconstruction quality. The anti-scatter grid will be important for in vivo XRF tomography since the background reduction allows for faster scan times, lower doses, and lower nanoparticle concentrations.

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2018
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-230827 (URN)10.1364/OL.43.002591 (DOI)000433963300043 ()29856437 (PubMedID)2-s2.0-85048058307 (Scopus ID)
Note

QC 20180619

Available from: 2018-06-19 Created: 2018-06-19 Last updated: 2018-10-16Bibliographically approved
Larsson, J. C., Vogt, C., Vågberg, W., Toprak, M., Dzieran, J., Arsenian-Henriksson, M. & Hertz, H. (2018). High-spatial-resolution x-ray fluorescence tomography with spectrally matched nanoparticles. Physics in Medicine and Biology, 63, 164001
Open this publication in new window or tab >>High-spatial-resolution x-ray fluorescence tomography with spectrally matched nanoparticles
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2018 (English)In: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 63, p. 164001-Article in journal (Refereed) Published
Abstract [en]

Present macroscopic biomedical imaging methods provide either morphology with high spatial resolution (e.g. CT) or functional/molecular information with lower resolution (e.g. PET). X-ray fluorescence (XRF) from targeted nanoparticles allows molecular or functional imaging but sensitivity has so far been insufficient resulting in low spatial resolution, despite long exposure times and high dose. In the present paper, we show that laboratory XRF tomography with metal-core nanoparticles (NPs) provides a path to functional/molecular biomedical imaging with ~100 µm resolution in living rodents. The high sensitivity and resolution rely on the combination of a high-brightness liquid-metal-jet x-ray source, pencil-beam optics, photon-counting energy-dispersive detection, and spectrally matched NPs. The method is demonstrated on mice for 3D tumor imaging via passive targeting of in-house-fabricated molybdenum NPs. Exposure times, nanoparticle dose, and radiation dose agree well with in vivo imaging.

Place, publisher, year, edition, pages
Institute of Physics (IOP), 2018
Keywords
x-ray, x-ray fluorescence, tomography, nanoparticles
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-233331 (URN)10.1088/1361-6560/aad51e (DOI)000441712300001 ()2-s2.0-85052501337 (Scopus ID)
Funder
Swedish Research CouncilWallenberg Foundations
Note

QC 20180828

Available from: 2018-08-15 Created: 2018-08-15 Last updated: 2018-10-16Bibliographically approved
Romell, J., Vagberg, W., Romell, M., Haggman, S., Ikram, S. & Hertz, H. (2018). Soft-Tissue Imaging in a Human Mummy: Propagation-based Phase-Contrast CT. Radiology, 289(3), 670-676
Open this publication in new window or tab >>Soft-Tissue Imaging in a Human Mummy: Propagation-based Phase-Contrast CT
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2018 (English)In: Radiology, ISSN 0033-8419, E-ISSN 1527-1315, Vol. 289, no 3, p. 670-676Article in journal (Refereed) Published
Abstract [en]

Purpose: To evaluate phase-contrast CT as a noninvasive alternative to histology in the study of ancient soft tissue. Materials and Methods: The imaging was performed between May 8 and June 13, 2017. A mummified human hand from ancient Egypt was imaged in a laboratory phase-contrast CT arrangement with propagation-based imaging. The experimental arrangement for propagation-based imaging included a microfocus x-ray source, a rotation stage for the sample, and an x-ray detector. The mummified hand was imaged in two different modes. First, a CT scan of the whole hand was performed in an overview arrangement. Then, a detailed scan of the tip of the middle finger was performed. With imaging distances tailored fora large magnification and to maximize die phase-contrast signal, the estimated resolution in the final images was 6-9 mu m. Results: The overview CT allowed identification tendons of the hand, as well as identification of arteries and nerves in the dehydrated soft tissue. In the detailed phase-contrast setting, virtual histology of the soft tissues of the fingertip could be performed. Blood vessels in the nail bed and the microanatomy of the bone marrow and hypodermis were imaged, and the layers of the skin could be distinguished. Round structures in the adipose tissue were identified as the reamins of adipocytes. Conclusion: Laboratory phase-contrast CT enables imaging of the anatomy and microanatomy of mummified soft tissue with sub-10-mu m resolution and may serve as a complement or alternative to the classic invasive histrologic methods used in soft-tissue paleopathology. (C) RSNA.2018

Place, publisher, year, edition, pages
RADIOLOGICAL SOC NORTH AMERICA, 2018
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-239987 (URN)10.1148/radiol.2018180945 (DOI)000450569200015 ()30251933 (PubMedID)2-s2.0-85056714548 (Scopus ID)
Funder
Swedish Research CouncilWallenberg Foundations
Note

QC 20181211

Available from: 2018-12-11 Created: 2018-12-11 Last updated: 2018-12-11Bibliographically approved
Häggmark, I., Vågberg, W., Hertz, H. & Burvall, A. (2017). Comparison of quantitative multi-material phase-retrieval algorithms in propagation-based phase-contrast X-ray tomography. Optics Express, 25(26), 33543-33558
Open this publication in new window or tab >>Comparison of quantitative multi-material phase-retrieval algorithms in propagation-based phase-contrast X-ray tomography
2017 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 25, no 26, p. 33543-33558Article in journal (Refereed) Published
Abstract [en]

Propagation-based phase-contrast X-ray imaging provides high-resolution, dose-efficient images of biological materials. A crucial challenge is quantitative reconstruction, referred to as phase retrieval, of multi-material samples from single-distance, and hence incomplete, data. In this work, the two most promising methods for multi-material samples, the parallel method, and the linear method, are analytically, numerically, and experimentally compared. Both methods are designed for computed tomography, as they rely on segmentation in the tomographic reconstruction. The methods are found to result in comparable image quality, but the linear method provides faster reconstruction. In addition, as already done for the parallel method, we show that the linear method provides quantitative reconstruction for monochromatic radiation.

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2017
National Category
Medical Image Processing
Identifiers
urn:nbn:se:kth:diva-224073 (URN)10.1364/OE.25.033543 (DOI)000418893200122 ()2-s2.0-85039066011 (Scopus ID)
Note

QC 20180314

Available from: 2018-03-14 Created: 2018-03-14 Last updated: 2018-09-06Bibliographically approved
Fogelqvist, E., Kördel, M., Carannante, V., Önfelt, B. & Hertz, H. (2017). Laboratory cryo x-ray microscopy for 3D cell imaging. Scientific Reports, 7, Article ID 13433.
Open this publication in new window or tab >>Laboratory cryo x-ray microscopy for 3D cell imaging
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2017 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 13433Article in journal (Refereed) Published
Abstract [en]

Water-window x-ray microscopy allows two-and three-dimensional (2D and 3D) imaging of intact unstained cells in their cryofixed near-native state with unique contrast and high resolution. Present operational biological water-window microscopes are based at synchrotron facilities, which limits their accessibility and integration with complementary methods. Laboratory-source microscopes have had difficulty addressing relevant biological tasks with proper resolution and contrast due to long exposure times and limited up-time. Here we report on laboratory cryo x-ray microscopy with the exposure time, contrast, and reliability to allow for routine high-spatial resolution 3D imaging of intact cells and cell-cell interactions. Stabilization of the laser-plasma source combined with new optics and sample preparation provide high-resolution cell imaging, both in 2D with ten-second exposures and in 3D with twenty-minute tomography. Examples include monitoring of the distribution of carbon-dense vesicles in starving HEK293T cells and imaging the interaction between natural killer cells and target cells.

Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP, 2017
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-217434 (URN)10.1038/s41598-017-13538-2 (DOI)000413188400014 ()29044158 (PubMedID)2-s2.0-85031924153 (Scopus ID)
Note

QC 20171117

Available from: 2017-11-17 Created: 2017-11-17 Last updated: 2017-11-17Bibliographically approved
Vågberg, W., Larsson, J. C. & Hertz, H. (2017). Removal of ring artifacts in microtomography by characterization of scintillator variations. Optics Express, 25(19), 23191-23198
Open this publication in new window or tab >>Removal of ring artifacts in microtomography by characterization of scintillator variations
2017 (English)In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 25, no 19, p. 23191-23198Article in journal (Refereed) Published
Abstract [en]

Ring artifacts reduce image quality in tomography, and arise from faulty detector calibration. In microtomography, we have identified that ring artifacts can arise due to highspatial frequency variations in the scintillator thickness. Such variations are normally removed by a flat-field correction. However, as the spectrum changes, e. g. due to beam hardening, the detector response varies non-uniformly introducing ring artifacts that persist after flat-field correction. In this paper, we present a method to correct for ring artifacts from variations in scintillator thickness by using a simple method to characterize the local scintillator response. The method addresses the actual physical cause of the ring artifacts, in contrary to many other ring artifact removal methods which rely only on image post-processing. By applying the technique to an experimental phantom tomography, we show that ring artifacts are strongly reduced compared to only making a flat-field correction.

Place, publisher, year, edition, pages
OPTICAL SOC AMER, 2017
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-215825 (URN)10.1364/OE.25.023191 (DOI)000411584600089 ()2-s2.0-85029526180 (Scopus ID)
Note

QC 20171017

Available from: 2017-10-17 Created: 2017-10-17 Last updated: 2018-09-06Bibliographically approved
Larsson, D. H., Vågberg, W., Yaroshenko, A., Yildirim, A. O. & Hertz, H. (2016). High-resolution short- exposure small-animal laboratory x-ray phase-contrast tomography. Scientific Reports, 6, Article ID 39074.
Open this publication in new window or tab >>High-resolution short- exposure small-animal laboratory x-ray phase-contrast tomography
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2016 (English)In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 39074Article in journal (Refereed) Published
Abstract [en]

X-ray computed tomography of small animals and their organs is an essential tool in basic and preclinical biomedical research. In both phase-contrast and absorption tomography high spatial resolution and short exposure times are of key importance. However, the observable spatial resolutions and achievable exposure times are presently limited by system parameters rather than more fundamental constraints like, e.g., dose. Here we demonstrate laboratory tomography with few-ten mu m spatial resolution and few-minute exposure time at an acceptable dose for small-animal imaging, both with absorption contrast and phase contrast. The method relies on a magnifying imaging scheme in combination with a high-power small-spot liquid-metal-jet electron-impact source. The tomographic imaging is demonstrated on intact mouse, phantoms and excised lungs, both healthy and with pulmonary emphysema.

Place, publisher, year, edition, pages
Nature Publishing Group, 2016
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-199480 (URN)10.1038/srep39074 (DOI)000389631500001 ()2-s2.0-85006105732 (Scopus ID)
Note

QC 20170120

Available from: 2017-01-20 Created: 2017-01-09 Last updated: 2018-09-06Bibliographically approved
Hertz, H. M., Burvall, A., Larsson, D. H., Larsson, J., Lundström, U., Vågberg, W. & Zhou, T. (2016). Propagation-based phase-contrast imaging with laboratory sources. In: Optics InfoBase Conference Papers: . Paper presented at Compact EUV and X-ray Light Sources, EUVXRAY 2016, 20 March 2016 through 22 March 2016. OSA - The Optical Society
Open this publication in new window or tab >>Propagation-based phase-contrast imaging with laboratory sources
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2016 (English)In: Optics InfoBase Conference Papers, OSA - The Optical Society , 2016Conference paper, Published paper (Refereed)
Abstract [en]

We demonstrate that propagation-based phase-contrast x-ray imaging with state-of-the art laboratory microfocus sources allows imaging of thick biomedical objects with very high spatial resolution. 

Place, publisher, year, edition, pages
OSA - The Optical Society, 2016
Keywords
Biomedical objects, Laboratory source, Micro focus, Phase contrast X-ray imaging, Phase-contrast imaging, State of the art, Very high spatial resolutions, Light sources
National Category
Physical Sciences
Identifiers
urn:nbn:se:kth:diva-207507 (URN)2-s2.0-85016454260 (Scopus ID)9781943580095 (ISBN)
Conference
Compact EUV and X-ray Light Sources, EUVXRAY 2016, 20 March 2016 through 22 March 2016
Note

Conference code: 134308; Export Date: 22 May 2017; Conference Paper; Correspondence Address: Hertz, H.M.; Dept. of Applied Physics, Royal Inst. of Technol. (KTH)Sweden; email: hertz@biox.kth.se. QC 20170607

Available from: 2017-06-07 Created: 2017-06-07 Last updated: 2018-02-27Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-2723-6622

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