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Tonello R, Conradsen K, Pedersen DB, Frisvad JR. Surface Roughness and Grain Size Variation When 3D Printing Polyamide 11 Parts Using Selective Laser Sintering. Polymers (Basel) 2023; 15:2967. [PMID: 37447613 DOI: 10.3390/polym15132967] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 06/06/2023] [Accepted: 06/22/2023] [Indexed: 07/15/2023] Open
Abstract
Selective laser sintering (SLS) is a well-established technology that is used for additive manufacturing. Significant efforts have been made to improve SLS by optimizing the powder deposition, laser beam parameters, and temperature settings. The purpose is to ensure homogeneous sintering and prevent geometric and appearance inaccuracies in the manufactured objects. We evaluated the differences in the surface roughness and grain size of curved objects manufactured by using upcoming SLS technology that features two CO laser sources. Our analysis was carried out on polyamide 11 (PA11), which is a sustainable biobased polymer that has been gaining popularity due to its high-performance properties: its low melting point, high viscosity, and excellent mechanical properties. By using a Taguchi experimental design and analysis of variance (ANOVA), we examined the influence on the surface roughness and grain size of the build setup, the presence of thin walls, and the position of the sample on the powder bed. We found significant differences in some surface roughness and grain size measurements when these parameters were changed.
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Affiliation(s)
- Riccardo Tonello
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
- Department of Civil and Mechanical Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Knut Conradsen
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - David Bue Pedersen
- Department of Civil and Mechanical Engineering, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Jeppe Revall Frisvad
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
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2
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Messer D, Atchapero M, Jensen MB, Svendsen MS, Galatius A, Olsen MT, Frisvad JR, Dahl VA, Conradsen K, Dahl AB, Bærentzen A. Using virtual reality for anatomical landmark annotation in geometric morphometrics. PeerJ 2022; 10:e12869. [PMID: 35186472 PMCID: PMC8830334 DOI: 10.7717/peerj.12869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/10/2022] [Indexed: 01/10/2023] Open
Abstract
To study the shape of objects using geometric morphometrics, landmarks are oftentimes collected digitally from a 3D scanned model. The expert may annotate landmarks using software that visualizes the 3D model on a flat screen, and interaction is achieved with a mouse and a keyboard. However, landmark annotation of a 3D model on a 2D display is a tedious process and potentially introduces error due to the perception and interaction limitations of the flat interface. In addition, digital landmark placement can be more time-consuming than direct annotation on the physical object using a tactile digitizer arm. Since virtual reality (VR) is designed to more closely resemble the real world, we present a VR prototype for annotating landmarks on 3D models. We study the impact of VR on annotation performance by comparing our VR prototype to Stratovan Checkpoint, a commonly used commercial desktop software. We use an experimental setup, where four operators placed six landmarks on six grey seal (Halichoerus grypus) skulls in six trials for both systems. This enables us to investigate multiple sources of measurement error. We analyse both for the configuration and for single landmarks. Our analysis shows that annotation in VR is a promising alternative to desktop annotation. We find that annotation precision is comparable between the two systems, with VR being significantly more precise for one of the landmarks. We do not find evidence that annotation in VR is faster than on the desktop, but it is accurate.
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Affiliation(s)
- Dolores Messer
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Michael Atchapero
- Department of Psychology, University of Copenhagen, Copenhagen, Denmark
| | - Mark B. Jensen
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby, Denmark
| | | | - Anders Galatius
- Department of Ecoscience, Aarhus University, Roskilde, Denmark
| | - Morten T. Olsen
- Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Jeppe R. Frisvad
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Vedrana A. Dahl
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Knut Conradsen
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Anders B. Dahl
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Andreas Bærentzen
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby, Denmark
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3
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Messer D, Svendsen MS, Galatius A, Olsen MT, Dahl VA, Conradsen K, Dahl AB. Measurement error using a SeeMaLab structured light 3D scanner against a Microscribe 3D digitizer. PeerJ 2021; 9:e11804. [PMID: 34484981 PMCID: PMC8381885 DOI: 10.7717/peerj.11804] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/27/2021] [Indexed: 12/03/2022] Open
Abstract
Background Geometric morphometrics is a powerful approach to capture and quantify morphological shape variation. Both 3D digitizer arms and structured light surface scanners are portable, easy to use, and relatively cheap, which makes these two capturing devices obvious choices for geometric morphometrics. While digitizer arms have been the “gold standard”, benefits of having full 3D models are manifold. We assessed the measurement error and investigate bias associated with the use of an open-source, high-resolution structured light scanner called SeeMaLab against the popular Microscribe 3D digitizer arm. Methodology The analyses were based on 22 grey seal (Halichoerus grypus) skulls. 31 fixed anatomical landmarks were annotated both directly using a Microscribe 3D digitizer and on reconstructed 3D digital models created from structured light surface scans. Each skull was scanned twice. Two operators annotated the landmarks, each twice on all the skulls and 3D models, allowing for the investigation of multiple sources of measurement error. We performed multiple Procrustes ANOVAs to compare the two devices in terms of within- and between-operator error, to quantify the measurement error induced by device, to compare between-device error with other sources of variation, and to assess the level of scanning-related error. We investigated the presence of general shape bias due to device and operator. Results Similar precision was obtained with both devices. If landmarks that were identified as less clearly defined and thus harder to place were omitted, the scanner pipeline would achieve higher precision than the digitizer. Between-operator error was biased and seemed to be smaller when using the scanner pipeline. There were systematic differences between devices, which was mainly driven by landmarks less clearly defined. The factors device, operator and landmark replica were all statistically significant and of similar size, but were minor sources of total shape variation, compared to the biological variation among grey seal skulls. The scanning-related error was small compared to all other error sources. Conclusions As the scanner showed precision similar to the digitizer, a scanner should be used if the advantages of obtaining detailed 3D models of a specimen are desired. To obtain high precision, a pre-study should be conducted to identify difficult landmarks. Due to the observed bias, data from different devices and/or operators should not be combined when the expected biological variation is small, without testing the landmarks for repeatability across platforms and operators. For any study necessitating the combination of landmark measurements from different operators, the scanner pipeline will be better suited. The small scanning-related error indicates that by following the same scanning protocol, different operators can be involved in the scanning process without introducing significant error.
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Affiliation(s)
- Dolores Messer
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
| | | | - Anders Galatius
- Department of Bioscience, Aarhus University, Roskilde, Denmark
| | - Morten T Olsen
- Globe Institute, University of Copenhagen, Copenhagen, Denmark
| | - Vedrana A Dahl
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Knut Conradsen
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Anders B Dahl
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Kongens Lyngby, Denmark
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Hansen AE, Henriksen JR, Jølck RI, Fliedner FP, Bruun LM, Scherman J, Jensen AI, Munck af Rosenschöld P, Moorman L, Kurbegovic S, de Blanck SR, Larsen KR, Clementsen PF, Christensen AN, Clausen MH, Wang W, Kempen P, Christensen M, Viby NE, Persson G, Larsen R, Conradsen K, McEvoy FJ, Kjaer A, Eriksen T, Andresen TL. Multimodal soft tissue markers for bridging high-resolution diagnostic imaging with therapeutic intervention. Sci Adv 2020; 6:eabb5353. [PMID: 32875113 PMCID: PMC7438096 DOI: 10.1126/sciadv.abb5353] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 07/07/2020] [Indexed: 05/11/2023]
Abstract
Diagnostic imaging often outperforms the surgeon's ability to identify small structures during therapeutic procedures. Smart soft tissue markers that translate the sensitivity of diagnostic imaging into optimal therapeutic intervention are therefore highly warranted. This paper presents a unique adaptable liquid soft tissue marker system based on functionalized carbohydrates (Carbo-gel). The liquid state of these markers allows for high-precision placement under image guidance using thin needles. Based on step-by-step modifications, the image features and mechanical properties of markers can be optimized to bridge diagnostic imaging and specific therapeutic interventions. The performance of Carbo-gel is demonstrated for markers that (i) have radiographic, magnetic resonance, and ultrasound visibility; (ii) are palpable and visible; and (iii) are localizable by near-infrared fluorescence and radio guidance. The study demonstrates encouraging proof of concept for the liquid marker system as a well-tolerated multimodal imaging marker that can improve image-guided radiotherapy and surgical interventions, including robotic surgery.
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Affiliation(s)
- Anders E. Hansen
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Jonas R. Henriksen
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Rasmus I. Jølck
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Frederikke P. Fliedner
- Dept. of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Dept. of Biomedical Sciences, Copenhagen University Hospital (Rigshospitalet) and University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Linda M. Bruun
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Jonas Scherman
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund SE-222 42, Sweden
| | - Andreas I. Jensen
- DTU Health Technology, The Hevesy Laboratory, Technical University of Denmark, Roskilde DK-4000, Denmark
| | - Per. Munck af Rosenschöld
- Radiation Physics, Department of Hematology, Oncology and Radiation Physics, Skåne University Hospital, Lund SE-222 42, Sweden
| | - Lilah Moorman
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Frederiksberg DK-1870, Denmark
| | - Sorel Kurbegovic
- Dept. of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Dept. of Biomedical Sciences, Copenhagen University Hospital (Rigshospitalet) and University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Steen R. de Blanck
- Department of Oncology, Copenhagen University Hospital (Rigshospitalet), Copenhagen DK-2100, Denmark
| | - Klaus R. Larsen
- Department of Respiratory Medicine, Copenhagen University Hospital (Bispebjerg and Frederiksberg Hospital), Copenhagen DK-2400, Denmark
| | - Paul F. Clementsen
- Copenhagen Academy for Medical Education and Simulation (CAMES), Department of Internal Medicine, Zealand University Hospital, Roskilde, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, DK-2100, Denmark
| | - Anders N. Christensen
- DTU Compute, Section for Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Mads H. Clausen
- Department of Cardiothoracic Surgery, Copenhagen University Hospital (Rigshospitalet), Copenhagen DK-2100, Denmark
| | - Wenbo Wang
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Paul Kempen
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Merete Christensen
- Department of Cardiothoracic Surgery, Copenhagen University Hospital (Rigshospitalet), Copenhagen DK-2100, Denmark
| | - Niels-Erik Viby
- Department of Cardiothoracic Surgery, Copenhagen University Hospital (Rigshospitalet), Copenhagen DK-2100, Denmark
| | - Gitte Persson
- Department of Oncology, Herlev-Gentofte Hospital, Department of Clinical Medicine, Faculty of Health Science, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Rasmus Larsen
- DTU Compute, Section for Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Knut Conradsen
- DTU Compute, Section for Applied Mathematics and Computer Science, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
| | - Fintan J. McEvoy
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Frederiksberg DK-1870, Denmark
| | - Andreas Kjaer
- Dept. of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Dept. of Biomedical Sciences, Copenhagen University Hospital (Rigshospitalet) and University of Copenhagen, Copenhagen, DK-2200, Denmark
| | - Thomas Eriksen
- Department of Veterinary Clinical and Animal Sciences, University of Copenhagen, Frederiksberg DK-1870, Denmark
| | - Thomas L. Andresen
- DTU Health Technology, Section for Biotherapeutic Engineering and Drug Targeting, Center for Nanomedicine and Theranostics, Technical University of Denmark, Kgs. Lyngby DK-2800, Denmark
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Trinderup CH, Møller F, Dahl AB, Conradsen K. Investigation of pausing fermentation of salamis with multispectral imaging for optimal sensory evaluations. Meat Sci 2018; 146:9-17. [PMID: 30081378 DOI: 10.1016/j.meatsci.2018.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 07/19/2018] [Accepted: 07/23/2018] [Indexed: 11/17/2022]
Abstract
The fermentation process of salamis involves several parameters influencing taste, texture, and color of the salami. One significant parameter is the fermentation time. It is difficult to conduct sensory evaluations to assess the effect of time without introducing variation between observation days. It may be possible to overcome this by stalling or pausing the fermentation by deep-chilling the salamis. This study investigates the difference of non- and deep-chilled salamis with the use of a multispectral imaging system. The statistical investigation, based on image features relating to size, visual texture, and color of the sausages over time, showed that it may be possible to stall the fermentation process. It was shown that a statistical difference in the two kinds of samples is present. For the size feature the difference could be quantified into a number of days. However, for the important color feature only a statistical difference was observed, whereas the visual difference expressed in terms of ΔEab⁎ was barely present.
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Affiliation(s)
- Camilla H Trinderup
- Technical University of Denmark, Richard Petersens Plads, 2800 Kgs. Lyngby, Denmark.
| | - Flemming Møller
- DuPont Nutrition Biosciences ApS, Edwin Rahrs Vej 38, 8220 Brabrand, Denmark.
| | - Anders Bjorholm Dahl
- Technical University of Denmark, Richard Petersens Plads, 2800 Kgs. Lyngby, Denmark.
| | - Knut Conradsen
- Technical University of Denmark, Richard Petersens Plads, 2800 Kgs. Lyngby, Denmark.
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6
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Emerson MJ, Dahl VA, Conradsen K, Mikkelsen LP, Dahl AB. A multimodal data-set of a unidirectional glass fibre reinforced polymer composite. Data Brief 2018; 18:1388-1393. [PMID: 30057939 PMCID: PMC6060273 DOI: 10.1016/j.dib.2018.04.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 04/05/2018] [Accepted: 04/11/2018] [Indexed: 11/26/2022] Open
Abstract
A unidirectional (UD) glass fibre reinforced polymer (GFRP) composite was scanned at varying resolutions in the micro-scale with several imaging modalities. All six scans capture the same region of the sample, containing well-aligned fibres inside a UD load-carrying bundle. Two scans of the cross-sectional surface of the bundle were acquired at a high resolution, by means of scanning electron microscopy (SEM) and optical microscopy (OM), and four volumetric scans were acquired through X-ray computed tomography (CT) at different resolutions. Individual fibres can be resolved from these scans to investigate the micro-structure of the UD bundle. The data is hosted at https://doi.org/10.5281/zenodo.1195879 and it was used in Emerson et al. (2018) [1] to demonstrate that precise and representative characterisations of fibre geometry are possible with relatively low X-ray CT resolutions if the analysis method is robust to image quality.
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Affiliation(s)
- Monica J Emerson
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Denmark
| | - Vedrana A Dahl
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Denmark
| | - Knut Conradsen
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Denmark
| | - Lars P Mikkelsen
- Department of Wind Energy, Technical University of Denmark, Denmark
| | - Anders B Dahl
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Denmark
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7
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Stets JD, Dal Corso A, Nielsen JB, Lyngby RA, Jensen SHN, Wilm J, Doest MB, Gundlach C, Eiriksson ER, Conradsen K, Dahl AB, Bærentzen JA, Frisvad JR, Aanæs H. Scene reassembly after multimodal digitization and pipeline evaluation using photorealistic rendering. Appl Opt 2017; 56:7679-7690. [PMID: 29047754 DOI: 10.1364/ao.56.007679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 08/15/2017] [Indexed: 06/07/2023]
Abstract
Transparent objects require acquisition modalities that are very different from the ones used for objects with more diffuse reflectance properties. Digitizing a scene where objects must be acquired with different modalities requires scene reassembly after reconstruction of the object surfaces. This reassembly of a scene that was picked apart for scanning seems unexplored. We contribute with a multimodal digitization pipeline for scenes that require this step of reassembly. Our pipeline includes measurement of bidirectional reflectance distribution functions and high dynamic range imaging of the lighting environment. This enables pixelwise comparison of photographs of the real scene with renderings of the digital version of the scene. Such quantitative evaluation is useful for verifying acquired material appearance and reconstructed surface geometry, which is an important aspect of digital content creation. It is also useful for identifying and improving issues in the different steps of the pipeline. In this work, we use it to improve reconstruction, apply analysis by synthesis to estimate optical properties, and to develop our method for scene reassembly.
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8
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Wessel Lindberg AS, Conradsen K, Larsen R, Friis Lippert M, Røge R, Vyberg M. Quantitative tumor heterogeneity assessment on a nuclear population basis. Cytometry A 2017; 91:574-584. [PMID: 28141908 DOI: 10.1002/cyto.a.23047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 10/09/2016] [Accepted: 12/08/2016] [Indexed: 01/07/2023]
Abstract
Immunohistochemistry Ki-67 stain is widely used for visualizing cell proliferation. The common method for scoring the proliferation is to manually select and score a hot spot. This method is time-consuming and will often not give reproducible results due to subjective selection of the hotspots and subjective scoring. An automatic hotspot detection and proliferative index scoring would be time-saving, make the determination of the Ki-67 score easier and minimize the uncertainty of the score by introducing a more objective and standardized score. Tissue Micro Array cores stained for Ki-67 and their neighbor slide stained for Pan Cytokeratin were aligned and Ki-67 positive and negative nuclei were identified inside tumor regions. A heatmap was calculated based on these and illustrates the distribution of the heterogenous response of Ki-67 positive nuclei in the tumor tissue. An automatic hot spot detection was developed and the Ki-67 score was calculated. All scores were compared with scores provided by a pathologist using linear regression models. No significant difference was found between the Ki-67 scores guided by the developed heatmap and the scores provided by a pathologist. For comparison, scores were also calculated at a random place outside the hot spot and these scores were found to be significantly different from the pathologist scores. A heatmap visualizing the heterogeneity in tumor tissue expressed by Ki-67 was developed and used for an automatic identification of hot spots in which a Ki-67 score was calculated. The Ki-67 scores did not differ significantly from scores provided by a pathologist. © 2017 International Society for Advancement of Cytometry.
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Affiliation(s)
| | - Knut Conradsen
- DTU Compute, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Rasmus Larsen
- DTU Compute, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | | | - Rasmus Røge
- Institute of Pathology, Aalborg University Hospital, DK-9100, Aalborg, Denmark
| | - Mogens Vyberg
- Institute of Pathology, Aalborg University Hospital, DK-9100, Aalborg, Denmark
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9
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Sun J, Zhang YB, Dahl AB, Conradsen K, Juul Jensen D. A method to characterize the roughness of 2-D line features: recrystallization boundaries. J Microsc 2016; 265:313-321. [PMID: 27896802 DOI: 10.1111/jmi.12501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 07/24/2016] [Accepted: 10/11/2016] [Indexed: 11/28/2022]
Abstract
A method is presented, which allows quantification of the roughness of nonplanar boundaries of objects for which the neutral plane is not known. The method provides quantitative descriptions of both the local and global characteristics. How the method can be used to estimate the sizes of rough features and local curvatures is also presented. The potential of the method is illustrated by quantification of the roughness of two recrystallization boundaries in a pure Al specimen characterized by scanning electron microscopy.
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Affiliation(s)
- J Sun
- Section for Materials Science and Advanced Characterization, Department of Wind Energy, Technical University of Denmark, Risø Campus, Roskilde, Denmark
| | - Y B Zhang
- Section for Materials Science and Advanced Characterization, Department of Wind Energy, Technical University of Denmark, Risø Campus, Roskilde, Denmark
| | - A B Dahl
- Section for Image Analysis and Computer Graphics, Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | - K Conradsen
- Section for Image Analysis and Computer Graphics, Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | - D Juul Jensen
- Section for Materials Science and Advanced Characterization, Department of Wind Energy, Technical University of Denmark, Risø Campus, Roskilde, Denmark
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10
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Christensen AN, Rydhög JS, Søndergaard RV, Andresen TL, Holm S, Munck Af Rosenschöld P, Conradsen K, Jølck RI. Injectable silver nanosensors: in vivo dosimetry for external beam radiotherapy using positron emission tomography. Nanoscale 2016; 8:11002-11011. [PMID: 27174233 DOI: 10.1039/c6nr00201c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Development of safe and efficient radiotherapy routines requires quantification of the delivered absorbed dose to the cancer tissue in individual patients. In vivo dosimetry can provide accurate information about the absorbed dose delivered during treatment. In the current study, a novel silver-nanosensor formulation based on poly(vinylpyrrolidinone)-coated silver nanoparticles formulated in a gelation matrix composed of sucrose acetate isobutyrate has been developed for use as an in vivo dosimeter for external beam radiotherapy. In situ photonuclear reactions trigger the formation of radioactive (106)Ag, which enables post treatment verification of the delivered dose using positron emission tomography imaging. The silver-nanosensor was investigated in a tissue equivalent thorax phantom using clinical settings and workflow for both standard fractionated radiotherapy (2 Gy) and stereotactic radiotherapy (10- and 22 Gy) in a high-energy beam setting (18 MV). The developed silver-nanosensor provided high radiopacity on the planning CT-scans sufficient for patient positioning in image-guided radiotherapy and provided dosimetric information about the absorbed dose with a 10% and 8% standard deviation for the stereotactic regimens, 10 and 22 Gy, respectively.
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Affiliation(s)
- A N Christensen
- DTU Compute, Department of Applied Mathematics and Computer Science, Technical University of Denmark, Building 321/324, Matematiktorvet, 2800 Kgs. Lyngby, Denmark
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11
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Jølck RI, Rydhög JS, Christensen AN, Hansen AE, Bruun LM, Schaarup-Jensen H, von Wenck AS, Børresen B, Kristensen AT, Clausen MH, Kjaer A, Conradsen K, Larsen R, af Rosenschöld PM, Andresen TL. Injectable Colloidal Gold for Use in Intrafractional 2D Image-Guided Radiation Therapy. Adv Healthc Mater 2015; 4:856-63. [PMID: 25607532 DOI: 10.1002/adhm.201400651] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 12/03/2014] [Indexed: 11/11/2022]
Abstract
In the western world, approximately 50% of all cancer patients receive radiotherapy alone or in combination with surgery or chemotherapy. Image-guided radiotherapy (IGRT) has in recent years been introduced to enhance precision of the delivery of radiation dose to tumor tissue. Fiducial markers are often inserted inside the tumor to improve IGRT precision and to enable monitoring of the tumor position during radiation therapy. In the present article, a liquid fiducial tissue marker is presented, which can be injected into tumor tissue using thin and flexible needles. The liquid fiducial has high radio-opacity, which allows for marker-based image guidance in 2D and 3D X-ray imaging during radiation therapy. This is achieved by surface-engineering gold nanoparticles to be highly compatible with a carbohydrate-based gelation matrix. The new fiducial marker is investigated in mice where they are highly biocompatible and stable after implantation. To investigate the clinical potential, a study is conducted in a canine cancer patient with spontaneous developed solid tumor in which the marker is successfully injected and used to align and image-guide radiation treatment of the canine patient. It is concluded that the new fiducial marker has highly interesting properties that warrant investigations in cancer patients.
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Affiliation(s)
- Rasmus I. Jølck
- DTU Nanotech, Department of Micro-and Nanotechnology; Center for Nanomedicine and Theranostics Technical University of Denmark; Building 345E, Ørsteds Plads; 2800 Lyngby Denmark
| | - Jonas S. Rydhög
- Department of Oncology Section of Radiotherapy 3994; Rigshospitalet; Blegdamsvej 9 2100 Copenhagen Denmark
- the Niels Bohr Institute, University of Copenhagen; Blegdamsvej 17 2100 Copenhagen Denmark
| | - Anders N. Christensen
- DTU Compute, Department of Applied Mathematics and Computer Science; Technical University of DenmarkBuilding 321/324; Matematiktorvet 2800 Lyngby Denmark
| | - Anders E. Hansen
- DTU Nanotech, Department of Micro-and Nanotechnology; Center for Nanomedicine and Theranostics Technical University of Denmark; Building 345E, Ørsteds Plads; 2800 Lyngby Denmark
| | - Linda M. Bruun
- DTU Nanotech, Department of Micro-and Nanotechnology; Center for Nanomedicine and Theranostics Technical University of Denmark; Building 345E, Ørsteds Plads; 2800 Lyngby Denmark
| | - Henrik Schaarup-Jensen
- DTU Chemistry Department of Chemistry Center for Nanomedicine and Theranostics; Technical University of Denmark; Building 207 Kemitorvet 2800 Lyngby Denmark
| | - Asger Stevner von Wenck
- Department of Veterinary Clinical and Animal Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Dyrlaegevej 16 1870 Frederiksberg C Denmark
| | - Betina Børresen
- Department of Veterinary Clinical and Animal Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Dyrlaegevej 16 1870 Frederiksberg C Denmark
| | - Annemarie T. Kristensen
- Department of Veterinary Clinical and Animal Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Dyrlaegevej 16 1870 Frederiksberg C Denmark
| | - Mads H. Clausen
- DTU Chemistry Department of Chemistry Center for Nanomedicine and Theranostics; Technical University of Denmark; Building 207 Kemitorvet 2800 Lyngby Denmark
| | - Andreas Kjaer
- Department of Clinical Physiology Nuclear Medicine & PET and Cluster for Molecular Imaging; Rigshospitalet and University of Copenhagen; Blegdamsvej 9 2100 Copenhagen Denmark
| | - Knut Conradsen
- DTU Compute, Department of Applied Mathematics and Computer Science; Technical University of DenmarkBuilding 321/324; Matematiktorvet 2800 Lyngby Denmark
| | - Rasmus Larsen
- DTU Compute, Department of Applied Mathematics and Computer Science; Technical University of DenmarkBuilding 321/324; Matematiktorvet 2800 Lyngby Denmark
| | - Per Munck af Rosenschöld
- Department of Oncology Section of Radiotherapy 3994; Rigshospitalet; Blegdamsvej 9 2100 Copenhagen Denmark
- the Niels Bohr Institute, University of Copenhagen; Blegdamsvej 17 2100 Copenhagen Denmark
| | - Thomas L. Andresen
- DTU Nanotech, Department of Micro-and Nanotechnology; Center for Nanomedicine and Theranostics Technical University of Denmark; Building 345E, Ørsteds Plads; 2800 Lyngby Denmark
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12
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Trinderup CH, Dahl A, Jensen K, Carstensen JM, Conradsen K. Comparison of a multispectral vision system and a colorimeter for the assessment of meat color. Meat Sci 2015; 102:1-7. [DOI: 10.1016/j.meatsci.2014.11.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 10/24/2022]
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13
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Anker CB, Pai A, Sørensen L, Lyksborg M, Larsen R, Conradsen K, Nielsen M. P1‐288: AUTOMATED HIPPOCAMPAL SEGMENTATION USING NEW STANDARDIZED MANUAL SEGMENTATIONS FROM THE HARMONIZED HIPPOCAMPAL PROTOCOL. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
| | - Akshay Pai
- University of CopenhagenCopenhagenDenmark
| | | | - Mark Lyksborg
- Technical University of DenmarkKongens LyngbyDenmark
| | - Rasmus Larsen
- Technical University of DenmarkKongens LyngbyDenmark
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14
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Anker CB, Pai A, Sørensen L, Lyksborg M, Larsen R, Conradsen K, Nielsen M. IC‐P‐058: AUTOMATED HIPPOCAMPAL SEGMENTATION USING NEW STANDARDIZED MANUAL SEGMENTATIONS FROM THE HARMONIZED HIPPOCAMPAL PROTOCOL. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
| | - Akshay Pai
- University of CopenhagenCopenhagenDenmark
| | | | - Mark Lyksborg
- Technical University of DenmarkKongens LyngbyDenmark
| | - Rasmus Larsen
- Technical University of DenmarkKongens LyngbyDenmark
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15
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Nielsen LB, Prahm LP, Berkowicz R, Conradsen K. Net incoming radiation estimated from hourly global radiation and/or cloud observations. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/joc.3370010305] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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16
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Aslanidi OV, Mornev OA, Skyggebjerg O, Arkhammar P, Thastrup O, Sørensen MP, Christiansen PL, Conradsen K, Scott AC. Excitation wave propagation as a possible mechanism for signal transmission in pancreatic islets of Langerhans. Biophys J 2001; 80:1195-209. [PMID: 11222284 PMCID: PMC1301315 DOI: 10.1016/s0006-3495(01)76096-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
In response to glucose application, beta-cells forming pancreatic islets of Langerhans start bursting oscillations of the membrane potential and intracellular calcium concentration, inducing insulin secretion by the cells. Until recently, it has been assumed that the bursting activity of beta-cells in a single islet of Langerhans is synchronized across the whole islet due to coupling between the cells. However, time delays of several seconds in the activity of distant cells are usually observed in the islets of Langerhans, indicating that electrical/calcium wave propagation through the islets can occur. This work presents both experimental and theoretical evidence for wave propagation in the islets of Langerhans. Experiments with Fura-2 fluorescence monitoring of spatiotemporal calcium dynamics in the islets have clearly shown such wave propagation. Furthermore, numerical simulations of the model describing a cluster of electrically coupled beta-cells have supported our view that the experimentally observed calcium waves are due to electric pulses propagating through the cluster. This point of view is also supported by independent experimental results. Based on the model equations, an approximate analytical expression for the wave velocity is introduced, indicating which parameters can alter the velocity. We point to the possible role of the observed waves as signals controlling the insulin secretion inside the islets of Langerhans, in particular, in the regions that cannot be reached by any external stimuli such as high glucose concentration outside the islets.
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Affiliation(s)
- O V Aslanidi
- Institute of Cell Biophysics RAS, Pushchino, Moscow Region, 142290 Russia
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17
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Andresen PR, Bookstein FL, Conradsen K, Ersbøll BK, Marsh JL, Kreiborg S. Surface-bounded growth modeling applied to human mandibles. IEEE Trans Med Imaging 2000; 19:1053-1063. [PMID: 11204843 DOI: 10.1109/42.896780] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
From a set of longitudinal three-dimensional scans of the same anatomical structure, we have accurately modeled the temporal shape and size changes using a linear shape model. On a total of 31 computed tomography scans of the mandible from six patients, 14,851 semilandmarks are found automatically using shape features and a new algorithm called geometry-constrained diffusion. The semilandmarks are mapped into Procrustes space. Principal component analysis extracts a one-dimensional subspace, which is used to construct a linear growth model. The worst case mean modeling error in a cross validation study is 3.7 mm.
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Affiliation(s)
- P R Andresen
- Department of Mathematical Modeling, Technical University of Denmark, Lyngby.
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Thyregod P, Conradsen K. [Using Statistics and Statistical Thinking to Improve Organisational Performance]: Discussion. Int Stat Rev 1999. [DOI: 10.2307/1403394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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20
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Frølich A, Nielsen BF, Conradsen K, McNair P, Transbøl IB. Within-centre evaluation of hypercalcaemia discriminant functions 5 years after their development. Int J Biomed Comput 1996; 40:235-240. [PMID: 8666476 DOI: 10.1016/0020-7101(95)01148-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Diagnostic hypercalcaemia discriminant functions, discriminating between clinically significant and non-significant hypercalcaemia, were tested 5 years after their development in order to evaluate the impact of time on their diagnostic capacity. Two populations, consisting of 257 and 129 patients with hypercalcaemia, were consecutively recorded, during six and three months respectively, 5 years apart under similar circumstances. The prevalence of hypercalcaemia was comparable in both populations, being 2.57 and 2.38% respectively (non-significant) (NS). The female/male ratio was 1.9 and 1.7 (NS). The discriminant functions correctly classified 81 and 80% of the women, respectively (NS) and respectively 75% and 64% of the men (NS) in the first and second recorded populations.
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Affiliation(s)
- A Frølich
- Department of Clinical Chemistry, Hvidovre Hospital, Copenhagen, Denmark
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Frølich A, Nielsen BF, Nielsen J, Conradsen K, McNair P. Do local hospitals meet the analytical goals for the use of common reference intervals? Scand J Clin Lab Invest 1994; 54:169-76. [PMID: 8197404 DOI: 10.3109/00365519409086524] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Blood samples were obtained from 183 blood donors and measured in two hospitals in the same geographical area using identical reference intervals and measuring equipment. The analytical bias of the clinical chemical analyses was investigated through paired measurements. The results showed that out of 15 routine analyses only four meet the goals for acceptance of common reference intervals, of which at least three were of clinical significance. The problems were reflected in the quality assessment results but, nevertheless, no action seems to have been taken.
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Affiliation(s)
- A Frølich
- Department of Clinical Chemistry, KAS Herlev, University of Copenhagen, Denmark
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Frølich A, Friis Nielsen B, Conradsen K, McNair P. Filtering clinically significant hypercalcaemia from non-significant hypercalcaemia at the laboratory level. Scand J Clin Lab Invest 1993; 53:215-23. [PMID: 8316750 DOI: 10.1080/00365519309088412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In an earlier study it was shown, that, in a hospital population, only about 30% of patients with hypercalcaemia had the diagnosis identified and so an alarm filter was developed, at the laboratory level, to differentiate between clinically significant and clinically non-significant hypercalcaemia. The filter correctly classified 84% and 77% of women and men with hypercalcaemia, respectively, with respect to the clinical significance of the hypercalcaemia. The sensitivity and the specificity of the discriminant functions were 90% and 73% in women and 80% and 67% in men. The alarm filter was based on a two-step procedure. The patients were primarily classified by the discriminant functions into one of the following medical diagnoses related to hypercalcaemia: primary hyperparathyroidism, malignancy, and transient hypercalcaemia. Based on this classification the patients were characterized as having either a clinically significant or non-significant hypercalcaemia. The alarm filter was based on two discriminant functions. The discriminant variables were phosphate, albumin, protein, LD, and a haemoglobin in women, and albumin, protein, ALP, and age in men. Missing values were estimated. The discriminant variables were selected from 17 possible discriminant variables, all measured by routine, and age. The study group comprised 257 patients with hypercalcaemia, consecutively registered, during half a year. The classification efficiency of the discriminant functions were based on comparison of results obtained by cross-validation of the discriminant functions, and the medical diagnosis decided by the clinicians in the respective departments of the hospital. The medical diagnoses were based on principles and definitions generally used in the departments with no knowledge of the results assessed by the discriminant functions.
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Affiliation(s)
- A Frølich
- Department of Clinical Chemistry, KAS Herlev, University of Copenhagen, Denmark
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Fredfeldt KE, Christensen E, Conradsen K, Ersbøll B, Stedstrup S. Automatic screening of plain film mammography. Semin Ultrasound CT MR 1992; 13:135-9. [PMID: 1599731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Using the computer as a diagnostic tool is a normal everyday function of modern radiology departments with CT, MRI, and ultrasound. This article describes the preliminary results using the computer as a coworker in a diagnostic scrutinizing process. Conventional analogous mammographic films were digitized and analyzed. Promising results were obtained detecting microcalcifications, dense areas, and their borderlines and stellate configurations. There are problems with detecting skin changes, probably caused by insufficient digitizing.
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Affiliation(s)
- K E Fredfeldt
- X-Ray Department, Central Hospital Hillerød, Denmark
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Søndergaard I, Poulsen LK, Hagerup M, Conradsen K. Image processing and pattern recognition algorithms for evaluation of crossed immunoelectrophoretic patterns (crossed radioimmunoelectrophoresis analysis manager; CREAM). Anal Biochem 1987; 165:384-91. [PMID: 3425908 DOI: 10.1016/0003-2697(87)90286-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A computerized method for automatic evaluation and comparison of crossed immunoelectrophoretic and crossed radioimmunoelectrophoretic patterns that requires limited hardware resources has been developed. For the initial reading of the plates an ordinary video camera is used. Feature extractors that allow the computer to recognize a point on the precipitation curve as being a peak point have been developed. After this automatic procedure the program allows for an interactive menu-driven proofreading phase during which it is possible to force the system to take into consideration any number of extra points along the precipitation curve in the curve-fitting process. The system has been tested on crossed immunoelectrophoretic patterns as well as crossed radioimmunoelectrophoretic patterns and it has been shown that the system can recognize the same precipitation curves on different immunoplates and autoradiographs. In addition, the system reports the mean, the variance, and the area of the precipitation curves, thus allowing not only a qualitative comparison of two or more plates but also a quantitation of individual antigens or antibodies.
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Affiliation(s)
- I Søndergaard
- Medical Department TTA, Righospitalet, University of Copenhagen, Denmark
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Conradsen K, Spliid H. A Seasonal Adjustment Filter for Use in Box Jenkins Analyses of Seasonal Time Series. J R Stat Soc Ser C Appl Stat 1981. [DOI: 10.2307/2346389] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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