Готові списки джерел за темами / Tomogram images

Добірка наукової літератури з теми "Tomogram images"

Автор: Grafiati
Опубліковано: 30 травня 2022
Оновлено: 31 травня 2022

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Статті в журналах з теми "Tomogram images"

1

Calcraft, Thomas, and Peter B. Rosenthal. "Cryogenic electron microscopy approaches that combine images and tilt series." Microscopy 71, Supplement_1 (February 18, 2022): i15—i22. http://dx.doi.org/10.1093/jmicro/dfab053.

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Abstract Cryogenic electron microscopy can be widely applied to biological specimens from the molecular to the cellular scale. In single-particle analysis, 3D structures may be obtained in high resolution by averaging 2D images of single particles in random orientations. For pleomorphic specimens, structures may be obtained by recording the tilt series of a single example of the specimen and calculating tomograms. Where many copies of a single structure such as a protein or nucleic acid assembly are present within the tomogram, averaging of the sub-volumes (subtomogram averaging) has been successfully applied. The choice of data collection method for any given specimen may depend on the structural question of interest and is determined by the radiation sensitivity of the specimen. Here, we survey some recent developments on the use of hybrid methods for recording and analysing data from radiation-sensitive biological specimens. These include single-particle reconstruction from 2D images where additional views are recorded at a single tilt angle of the specimen and methods where image tilt series, initially used for tomogram reconstruction, are processed as individual single-particle images. There is a continuum of approaches now available to maximize structural information obtained from the specimen.
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2

Verhey, Peter T., Marc V. Gosselin, Steven L. Primack, Paul L. Blackburn, and Alexander C. Kraemer. "The Right Mediastinal Border and Central Venous Anatomy on Frontal Chest Radiograph—Direct CT Correlation." Journal of the Association for Vascular Access 13, no. 1 (March 1, 2008): 32–35. http://dx.doi.org/10.2309/java.13-1-7.

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Abstract We describe a direct and accurate method for defining chest radiographic anatomy and use this method to delineate the anatomic composition of the right mediastinal border in an adult population. Intravenous contrast-enhanced computed tomographic scans of the chest and accompanying scout tomograms from 99 adults without previously known or detected cardiopulmonary disease that could potentially distort mediastinal, cardiac, or pulmonary anatomy were retrospectively evaluated. Transverse CT images through the mediastinum were directly referenced to the respective acquisition location on the scout tomogram via the acquisition reference line. The anatomic composition of the right mediastinal border on the scout tomogram was determined by drawing a vertical line tangential to the most lateral right mediastinal structure in each transverse CT image. The lengths and relationships of these structures were tabulated. These results will help to create a consensus among radiologists and other clinicians regarding radiographic anatomy, allowing improved localization of mediastinal pathology and enabling more optimal positioning of vascular and cardiac support devices.
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3

Yang, Mino, Jun-Ho Lee, Hee-Goo Kim, Euna Kim, Young-Nam Kwon, Jin-Gyu Kim, and Cheol-Woong Yang. "Meso-Scale Transmission Electron Microscope Tomography Applied for Wax Distribution in Toner Particles." Microscopy and Microanalysis 19, S5 (August 2013): 58–61. http://dx.doi.org/10.1017/s1431927613012336.

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AbstractDistribution of wax in laser printer toner was observed using an ultra-high-voltage (UHV) and a medium-voltage transmission electron microscope (TEM). As the radius of the wax spans a hundred to greater than a thousand nanometers, its three-dimensional recognition via TEM requires large depth of focus (DOF) for a volumetric specimen. A tomogram with a series of the captured images would allow the determination of their spatial distribution. In this study, bright-field (BF) images acquired with UHV-TEM at a high tilt angle prevented the construction of the tomogram. Conversely, the Z-contrast images acquired by the medium-voltage TEM produced a successful tomogram. The spatial resolution for both is discussed, illustrating that the image degradation was primarily caused by beam divergence of the Z-contrast image and the combination of DOF and chromatic aberration of the BF image from the UHV-TEM.
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4

Yedra, Lluís, Alberto Eljarrat, José Manuel Rebled, Lluís López-Conesa, Nico Dix, Florencio Sánchez, Sònia Estradé, and Francesca Peiró. "EELS tomography in multiferroic nanocomposites: from spectrum images to the spectrum volume." Nanoscale 6, no. 12 (2014): 6646–50. http://dx.doi.org/10.1039/c4nr01100g.

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5

Russell, Greg, Silvia N. W. Hertzberg, Natalia Anisimova, Natalia Gavrilova, Beáta É. Petrovski, and Goran Petrovski. "Digital Image Analysis of the Angle and Optic Nerve: A Simple, Fast, and Low-Cost Method for Glaucoma Assessment." Journal of Ophthalmology 2020 (October 28, 2020): 1–8. http://dx.doi.org/10.1155/2020/3595610.

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Purpose. To devise a simple, fast, and low-cost method for glaucoma assessment using digital image analysis of the angle and optic nerve in human subjects. Methods. Images from glaucoma and fundus assessment were used in this study, including color fundus photographs, standard optic nerve optical coherence tomography (OCT), and digital slit-lamp images of the angle/gonioscopy. Digital image conversion and analysis of the angle using ImageJ (NIH, USA) and adaptive histogram equalization contrast-limited AHE (CLAHE) to prevent noise amplification were implemented. Angle and optic nerve images were analyzed separately in the red, green, and blue (RGB) channels followed by 3D volumetric analysis of the degrees of angle depth and cup volume of the optic nerve. Horizontal tomogram reconstitution and nerve fiber detection methods were developed and compared to standard OCT images. Results. Digital slit-lamp angle images showed similar accuracy as standard anterior OCT measurements. Comparative analysis of RGB channels produced volumetric cup and horizontal tomogram, which closely resembled the 3D OCT appearance and B-scan of the cup, respectively. RGB channel splitting and image subtraction produced a map closely resembling that of the retinal nerve fiber layer (RNFL) thickness map on OCT. Conclusions. While OCT imaging is rapidly progressing in the area of optic disc and chamber angle assessment, rising healthcare costs and lack of availability of the technology open a demand for alternative and cost-minimizing forms of image analysis in glaucoma. Volumetric, geometric, and segmentational data obtained through digital image analysis correspond well to those obtained by OCT imaging.
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6

Lee, Doo Sung, Spyros K. Lazaratos, and Arthur F. Walden. "Crosswell seismic study in a seismically poor data area." GEOPHYSICS 60, no. 3 (May 1995): 758–64. http://dx.doi.org/10.1190/1.1443814.

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Crosswell traveltime tomography and reflection imaging assisted a reservoir characterization effort in an area of poor‐quality surface seismic data. Both the tomogram and the reflection image proved useful in the description of the fractured reservoir interval. The velocity tomogram shows that: (1) the vertical resolution was sufficient to identify and characterize a 50-ft (15 m) thick lithological unit of brittle rocks, which was the most important interval for the characterization of this fractured reservoir; (2) different lithological units present sufficient velocity contrast to be identifiable on the tomogram; and (3) the tomogram velocity is higher than the sonic velocity implying that the rocks in the interwell area may be anisotropic. Correlation of the lithologies with the tomogram implies that the major controlling factor of the anisotropy is the shale content in the formation. The crosswell reflection image, generated by a VSP‐CDP mapping technique, defines the fractured reservoir interval in terms of high‐frequency reflections. The lateral resolution of this reflection image is difficult to define because the survey coverage is nonuniform as a result of the receiver spacing being much larger than the source spacing. The dips of the reflections do not quite agree with the dips that are inferred from well log ties. We believe this disagreement is a result of the anisotropy of the medium and the use of an isotropic imaging algorithm. Improved data acquisition (finer spatial sampling) that would allow better wavefield separation techniques to be used would probably have produced higher quality crosswell reflection images.
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7

Jebelli, Mohammad, Kemp Kernstine, Mohammad Hossein Mandegar, Sam Chitsaz, and Hussein Rayatzadeh. "Left Ventricular Pseudoaneurysm Demonstrated by 64-Multislice Computed Tomography." Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery 4, no. 4 (July 2009): 236. http://dx.doi.org/10.1097/imi.0b013e3181b01c36.

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A 50-year-old man with a history of left ventricular aneurysmectomy was evaluated with a 64-multislice computed tomogram, which demonstrated left ventricular enlargement and a pseudoaneurysm at the apicolateral side. The images were critical to our management. We resected the pseudoaneurysm with an excellent outcome.
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8

Argunova, T. S., V. G. Kohn, J. H. Lim, Z. V. Gudkina, and E. D. Nazarova. "Computer simulations of X-ray phase-contrast images and microtomographic observation of tubules in dentin." Journal of Synchrotron Radiation 27, no. 2 (January 27, 2020): 462–67. http://dx.doi.org/10.1107/s1600577519016503.

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An investigation of the problems of X-ray imaging of dentinal tubules is presented. Two main points are addressed. In the first part of this paper, the problem of computer simulating tubule images recorded in a coherent synchrotron radiation (SR) beam has been discussed. A phantom material which involved a two-dimensional lattice of the tubules with parameters similar to those of dentin was considered. By a comparative examination of two approximations, it was found that the method of phase-contrast imaging is valid if the number of tubules along the beam is less than 100. Calculated images from a lattice of 50 × 50 tubules are periodic in free space but depend strongly on the distance between the specimen and the detector. In the second part, SR microtomographic experiments with millimetre-sized dentin samples in a partially coherent beam have been described. Tomograms were reconstructed from experimental projections using a technique for incoherent radiation. The main result of this part is the three-dimensional rendering of the directions of the tubules in a volume of the samples. Generation of the directions is possible because a tomogram shows the positions of the tubules. However, a detailed tubule cross-section structure cannot be restored.
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9

Padgett, Elliot, Robert Hovden, Jessica C. DaSilva, Barnaby D. A. Levin, John L. Grazul, Tobias Hanrath, and David A. Muller. "A Simple Preparation Method for Full-Range Electron Tomography of Nanoparticles and Fine Powders." Microscopy and Microanalysis 23, no. 6 (December 2017): 1150–58. http://dx.doi.org/10.1017/s1431927617012764.

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AbstractElectron tomography has become a valuable and widely used tool for studying the three-dimensional nanostructure of materials and biological specimens. However, the incomplete tilt range provided by conventional sample holders limits the fidelity and quantitative interpretability of tomographic images by leaving a “missing wedge” of unknown information in Fourier space. Imaging over a complete range of angles eliminates missing wedge artifacts and dramatically improves tomogram quality. Full-range tomography is usually accomplished using needle-shaped samples milled from bulk material with focused ion beams, but versatile specimen preparation methods for nanoparticles and other fine powders are lacking. In this work, we present a new preparation technique in which powder specimens are supported on carbon nanofibers that extend beyond the end of a tungsten needle. Using this approach, we produced tomograms of platinum fuel cell catalysts and gold-decorated strontium titanate photocatalyst specimens. Without the missing wedge, these tomograms are free from elongation artifacts, supporting straightforward automatic segmentation and quantitative analysis of key materials properties such as void size and connectivity, and surface area and curvature. This approach may be generalized to other samples that can be dispersed in liquids, such as biological structures, creating new opportunities for high-quality electron tomography across disciplines.
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10

Gan, Lu, and Grant J. Jensen. "Electron tomography of cells." Quarterly Reviews of Biophysics 45, no. 1 (November 15, 2011): 27–56. http://dx.doi.org/10.1017/s0033583511000102.

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AbstractThe electron microscope has contributed deep insights into biological structure since its invention nearly 80 years ago. Advances in instrumentation and methodology in recent decades have now enabled electron tomography to become the highest resolution three-dimensional (3D) imaging technique available for unique objects such as cells. Cells can be imaged either plastic-embedded or frozen-hydrated. Then the series of projection images are aligned and back-projected to generate a 3D reconstruction or ‘tomogram’. Here, we review how electron tomography has begun to reveal the molecular organization of cells and how the existing and upcoming technologies promise even greater insights into structural cell biology.
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Більше джерел

Дисертації з теми "Tomogram images"

1

Шамраєва, О. О. "Методи та засоби побудови комп’ютерних моделей черепних імплантатів за томографічними та рентгенографічними даними". Thesis, ХНУРЕ, 2009. http://openarchive.nure.ua/handle/document/11423.

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Дисертаційна робота присвячена розробці методів і засобів автоматизованої побудови моделі черепного імплантату та підвищенню точності планування нейрохірургічних операцій щодо реконструкції дефектів черепа. У роботі проведено огляд існуючих методів і засобів для побудови черепних імплантатів. Розглянуто основні методи обробки інтроскопічних зображень. Розроблено комплексний підхід до обробки томографічних і рентенографічних зображень голови пацієнта. Розроблено методи автоматизованої побудови об’ємних комп'ютерних моделей ЧІ за КТ- і РГ-даними з використанням 3D-моделі черепа пацієнта та усередненої моделі черепа. Розроблено метод автоматизованого визначення геометричних характеристик ЧІ, що дозволяє хірургу визначити оптимальний оперативний доступ. Розроблено медико-технічні вимоги до нейрохірургічного комплексу, призначеного для одержання вихідних даних, їхньої обробки й виготовлення речовинної копії імплантату. Проведено порівняльний аналіз отриманих результатів побудови моделей ЧІ із вже існуючими. Результати аналізу показали ефективність розроблених методів. Dissertation work considers the development of methods and facilities of the automatized construction of cranial implant model and the increase of procision of planning of neuro-surgical operative interferences for the reconstruction of cranial defects. The review of existent methods and facilities for the construction of cranial implants is provided. The basic methods of processing of introscopy images are considered. The complex approach is developed for treatment of patient’s head tomography and X-ray images. Methods of the automatized construction of three-dimensional computer models of cranial implant are developed on a base of tomography and X-ray data with the use of 3Dmodel of patient’s cranium and cranium average model. The method of the automatized determination of geometrical descriptions of cranial implant allowing a surgeon to define optimum operative access is developed. The basic medical-technical specifications are developed to neuro-surgical complex intended for the basic data obtaining, their treatment and making of implant material copy. The comparative analysis of the obtained results of models of cranial implants construction and already existing one is conducted. The results of analysis showed efficiency of the developed methods.
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2

Stearns, Charles William. "Accelerated image reconstruction for a cylindrical positron tomograph using Fourier domain methods." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/29201.

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Анотація:
Thesis (Ph. D.)--Harvard University--Massachusetts Institute of Technology Division of Health Sciences and Technology, Program in Medical Engineering and Medical Physics, 1990.
Includes bibliographical references (leaves 142-150).
by Charles William Stearns.
Ph.D.
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3

ALMEIDA, Raphael Lima Nobre de. "Detecção e classificação de nódulos de câncer de pulmão para diagnóstico assistido por computador." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/21011.

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Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-08-30T12:16:52Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) Dissertação - Raphael Lima Nobre de Almeida.pdf: 3877614 bytes, checksum: fb5c13466242f36f8e80a7bfdbe436ab (MD5)
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O câncer de pulmão tem se mostrado o mais agressivo e mortal dentre os tipos de câncer existentes. Uma das principais formas de combatê-lo eficientemente é através do diagnóstico precoce, porém, devido ao alto número de exames de tomografia analisados, vários casos tendem a passar despercebidos. Uma das maneiras de amenizar o problema é o uso de CAD para servir como segunda opinião no momento do diagnóstico. Esse trabalho apresenta um novo sistema CAD, tendo como resultado a indicação de nódulos presentes em exames de tomografia computadorizada do tórax de pacientes. O sistema proposto se baseia em propriedades matemáticas extraídas das regiões candidatas para determinar se elas são nódulos ou não, e a classificação é realizada usando um paralelo entre classificadores baseados em aprendizagem supervisionada e não-supervisionada. Foram estudados vários métodos CAD para definição de uma estrutura de processo automática, em todas as etapas, que primeiro realiza a segmentação da imagem do pulmão a partir de exames de tomografia computadorizada, depois extrai ROI contendo áreas com potencial presença de nódulos, e depois realiza a classificação das ROIs entre áreas com Nódulos e Não-nódulos. Uma base de dados pública de imagens de exames de pacientes LIDC, internacionalmente usada na concepção e testes de sistemas CAD, foi empregada. SOM e SVM foram investigados como classificadores. Como resultado, foram obtidos valores acima de 85% de acurácia, 88% de sensibilidade, 86% F-measure e 1,59 FP/Slice para o SVM e valores acima de 81% de acurácia e 86% de sensibilidade, 82% F-measure e 2,05 FP/Slice para o SOM, onde o FP/Slice significa a média de falsos positivos gerados por imagem. O sistema proposto apresentou resultados superiores em alguns aspectos quando comparados a metodos anteriores e ligeiramente inferior quando comparado com um sistema CAD de saída semelhante, mas que realiza a segmentação manual das regiões de interesse. A partir dos resultados, foi possível ratificar a viabilidade de sistemas CAD com um novo sistema para o diagnóstico de nódulos de câncer de pulmão.
Lung cancer has demonstrated to be the most aggressive and mortal among all kinds of cancer. One of the main manners to efficiently defeat it is the early diagnostic, although due the high number of exams of computed tomography analyzed by the radiologists, they tend to let scape some true cases. A suitable way to diminish this problem is using CAD systems to be used as a second opinion during diagnostic task. Therefore, this work presents a new CAD system , showing as result the indication of the present nodules in thoracic computed tomography exams. The proposed system is based on mathematical properties extracted from Região de Interesse (Region of Interest) (ROI)s to define if they are nodules or not, the classification is accomplished using a parallel between supervised and unsupervised learning techniques.It was studied a gamut of Sistemas para Diagnóstico Assistido por Computador (Computer Aided Diagnosis) (CAD) methods to determine a struct of process, and a base of comparison between the methods. The chosen database was (Lung Image Database Consortium) (LIDC), because it is a public base, internationally used and has diagnostic to each ROI. Mapa Auto-organizável de Kohonen (Self-Organizing Map) (SOM) and Máquina de Vetor de Suporte (Support Vector Machine) (SVM) was used as classifiers, to trace a study of results among them.As result, SVM achieved more than 85% of accuracy, 86% F-measure, 88% of sensibility and 1,59 of FP/Slice. About SOM, the best parametric configuration resulted in more than 81% of accuracy, 85% of sensibility, 82% F-measure and 2,05 of FP/Slice. Thus, it was possible to deduce that the proposed system presents better score when compared with equivalents methods, and lightly worse when compared with a CAD that has ROIs segmented manually. Based on gathered results, it was possible to ratify the importance and the possibility of CAD applications, as well as presents a new system able to perform equivalent task.
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4

Angelis, Georgios. "Novel spatiotemporal image reconstruction for high resolution PET imaging in neuroscience." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/novel-spatiotemporal-image-reconstruction-for-high-resolution-pet-imaging-in-neuroscience(8a251bc6-3ba6-48e2-8a7e-7fb0c0726ba0).html.

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Positron emission tomography (PET) is a widely used molecular imaging modality,which offers quantitative information about many biochemical processes in vivo. In particular, the dynamic PET data provide physiologically meaningful parametricimages after the estimation of the parameters of a model that best describes thekinetic behaviour of the injected radiotracer. Spatiotemporal 4D image reconstructionalgorithms estimate these physiological parameters directly from the raw sinogramdata, where the noise distribution can be more accurately modelled and thus leading tostatistically more reliable parameter estimates. In this thesis a novel direct parametricimage reconstruction algorithm is introduced, which is based on the expectationmaximisation (EM) framework and is applicable to any spatiotemporal model. Themethod is evaluated for the spectral analysis model, which is a linear temporal modeland a two-tissue compartment model, which is a nonlinear temporal model. Inaddition, the method is evaluated for a linear spatial model and in particular the modelthat is normally used to describe the blurring components in image-based resolutionmodelling. Finally, the performance of gradient-based 3D reconstruction algorithmswas also assessed as an alternative to the well-established EM-based algorithms.
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5

Yu, Zhou [Verfasser], Achilleas [Akademischer Betreuer] Frangakis, and Jochen [Akademischer Betreuer] Triesch. "From tomograms to molecular structure : image processing in cryo-electron tomography / Zhou Yu. Gutachter: Achilleas Frangakis ; Jochen Triesch." Frankfurt am Main : Univ.-Bibliothek Frankfurt am Main, 2015. http://d-nb.info/1071235648/34.

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6

Malusek, Alexandr. "Calculation of scatter in cone beam CT : Steps towards a virtual tomograph." Doctoral thesis, Linköping : Department of Medical and Health Sciences, Linköping University, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11275.

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7

Picolli, Patricia. "Dimens?o volum?trica na regi?o alveolar da fissura labiopalatina obtida pela an?lise da imagem tomogr?fica computadorizada com o software Image J." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2008. http://tede2.pucrs.br/tede2/handle/tede/1016.

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A Tomografia Computadorizada (TC) tem ocupado lugar de destaque em trabalhos cient?ficos que demonstram sua utiliza??o cl?nica, qualidade superior de imagem e precis?o em medidas relativas aos ossos da face. No entanto, a utilidade da TC na avalia??o de anomalias craniofaciais n?o depende apenas da precis?o do m?todo, mas tamb?m da sua reprodutibilidade entre diferentes observadores. A presente pesquisa analisa a capacidade de um software biom?dico de dom?nio p?blico em delimitar o defeito ?sseo alveolar inerente ? fissura labiopalatina e mensur?-lo volumetricamente. A amostra foi constitu?da de imagens tomogr?ficas computadorizadas de vinte e um pacientes portadores de fissura labiopalatina transforame incisivo, sendo treze do g?nero masculino e oito do g?nero feminino, com m?dia de idade de dez anos e cinco meses. Os arquivos DICOM foram acessados a partir de CD-R atrav?s do software IMAGE J 1.38, instalado em computador pessoal. Ap?s a devida importa??o da seq??ncia de imagens tomogr?ficas, visualiza??o e estudo de todos os cortes, foram selecionados aqueles correspondentes ? regi?o de interesse para cada paciente. Procederam-se os delineamentos e suas respectivas mensura??es. Os resultados demonstraram um volume m?dio do defeito ?sseo alveolar inerente ? fissura de 0,77? 0,17 cm?. Na avalia??o do m?todo, a concord?ncia intra e inter-observadores foi de 95,2% e 90,5%, respectivamente. A partir da metodologia empregada e dos resultados obtidos, concluiu-se que ? poss?vel por meio do software Image J 1.38 a delimita??o nas imagens tomogr?ficas, de regi?es de interesse de estruturas anat?micas faciais e o c?lculo volum?trico da ?rea delimitada.
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BARBOSA, Valter Augusto de Freitas. "Reconstrução de imagens de tomografia por impedância elétrica utilizando busca por cardumes de peixes e evolução diferencial". Universidade Federal de Pernambuco, 2017. https://repositorio.ufpe.br/handle/123456789/25153.

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FACEPE
A Tomografia por Impedância Elétrica (TIE) é uma técnica de imagem não invasiva e livre de radiações ionizantes. Sua realização dar-se através de um conjunto de eletrodos dispostos na superfície do objeto ao qual se quer imagear. Pelos eletrodos é aplicado uma corrente elétrica de baixa amplitude, e em seguida, os potenciais elétricos resultantes à excitação são medidos. Em um algoritmo de reconstrução os dados de corrente e potenciais elétricos são usados para estimar a distribuição de condutividade interna do objeto à qual pode ser representada por uma imagem. O problema de reconstrução de imagens de TIE consiste na solução dos problemas direto e inverso. No problema direto é determinado os potenciais elétricos internos e de superfície da seção do objeto a partir do padrão de excitação de corrente e da distribuição de condutividade interna do domínio. Sendo tal problema, resolvido através do método dos elementos finitos. Por outro lado, a estimação da distribuição de condutividade elétrica do interior da seção do corpo a partir das medições da resposta a excitação é, matematicamente, um problema inverso, mal posto e mal condicionado. Sendo um problema complexo, de alto custo computacional, e que ainda obtém imagens de contorno suave e de baixa resolução. Uma das formas de reconstrução de TIE é através de métodos iterativos de otimização, onde o problema direto é chamado frequentemente. Este trabalho propõe a reconstrução de imagens de TIE como um método de otimização utilizando algoritmos evolucionários e bioinspirados da Inteligência Computacional tendo o Erro Médio Quadrático como função objetivo a ser minimizada. As técnicas consideradas foram: Algoritmos genéticos, Evolução Diferencial, Busca por Cardumes de Peixes e Busca por cardumes de peixes baseada em densidade, além da implementação da Busca não-cega à Busca por Cardumes de Peixes. Os algoritmos de reconstrução foram implementados em MATLAB e fazendo uso do software de código aberto EIDORS. Os experimentos foram realizados utilizando imagens padrão ouro de duas malhas de elementos finitos. De forma qualitativa as imagens obtidas foram comparadas com as imagens padrão ouro consideradas, enquanto que de forma quantitativa foi avaliado os gráficos da queda do erro em função do número de avaliações da função e pelo número de iterações dos algoritmos. As melhores imagens foram obtidas pela busca por cardume de peixes com a busca não-cega, no entanto, os menores tempos de reconstrução foram obtidos pela evolução diferencial e algoritmos genéticos.
Electrical Impedance Tomography (EIT) is a noninvasive imaging technique and free of ionizing radiation. Its implementation is given through a set of electrodes placed on object surface to be imaged. By the electrodes, a low amplitude electric current is applied, then, the resultant electric potential to the excitation is measured. In a reconstruction algorithm, the data of the current and electrical potentials are used to estimate the intern conductivity distribution of the object which it can be represented by an image. The reconstruction problem of EIT images consists in to solve the direct and inverse problems. In the direct problem is determined the intern and surface electrical potentials of the object section from the excitation pattern of electric current and the intern conductivity distribution. Such problem is resolved by the finite elements method. On the other hand, the estimation of the electrical conductivity distribution of the interior of the body section from the measures of the response to the excitation is, mathematically, an inverse problem, ill-posed and ill-conditioned. Being a complex problem, of high computational cost, and still obtains low-resolution and soft-contour images. One of the ways to reconstruct EIT images is trough iterative optimization methods, which the direct problem is used often. This work proposes the EIT image reconstruction as an optimization method using evolutionary and bioinspired algorithms from Computational Intelligence having the Root Mean Squared Error as objective function to be minimized. The techniques considered were: Genetic Algorithm, Differential Evolution, Fish School Search and Density based on Fish School Search, beyond the implementation of the Non-Blind Search to Fish School Search. The reconstruction algorithms were implemented in MATLAB using the open-source software EIDORS. Experiments were made using ground-truth images of two finite elements meshes. Qualitatively the images obtained were compared with the ground-truth images considered, whereas quantitatively were considered the graphics of the root-mean-squared error in function of the number of evaluations of objective function and in function of the number of iterations of the algorithms. The best images were obtained by the fish school search with non-blind search, however, the smallest reconstruction time were obtained by differential evolution and genetic algorithms.
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Kochovski, Zdravko [Verfasser], Wolfgang [Akademischer Betreuer] Baumeister, and Martin [Akademischer Betreuer] Zacharias. "Image analysis of molecular complexes present in cryo-tomograms of neuronal synapses / Zdravko Kochovski. Gutachter: Martin Zacharias ; Wolfgang Baumeister. Betreuer: Wolfgang Baumeister." München : Universitätsbibliothek der TU München, 2014. http://d-nb.info/1054753075/34.

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Paulino, José Alberto Souza. "Desenvolvimento de uma ferramenta para automatizar redução de artefato metálico em imagens de tomografias computadorizadas." Universidade Estadual da Paraíba, 2017. http://tede.bc.uepb.edu.br/jspui/handle/tede/2859.

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This research proposes to evaluate and implement a solution for metal artifact reduc- tion in computed tomography, this one aiming to meet a demand from the prototyping laboratory of the Núcleo de Tecnologias Estratégicas em Saúde (Nutes) da Univer- sidade Estadual da Paraíba, where impressions of biomodels are made for surgical planning. The CT affected by metal artifacts need to be corrected prior to the printing process, this manual intervention implies excessive delay for delivery of the biomodels. The development of the proposed solution is based on the sinogram correction method which according to Mouton et al (2013) and Gjesteby (2016) is the most utilized method for reducing metal artifacts and makes uses of linear interpolation to correction the cor- rupted data. In order to validate the preference for linear interpolation in the state of the art, others interpolative techniques were implemented and evaluated; Fist through simulations and then by a form for qualitative evaluation, upon which statistical tests were applied. The results obtained confirm the use of interpolation as the best option for the reconstruction of data corrupted by metallic artifacts.
Esta pesquisa se propõe a avaliar e implementar uma solução para redução de artefatos metálicos em tomografias computadorizadas, solução esta que visa atender uma demanda do laboratório de prototipagem do Núcleo de Tecnologias Estratégicas em Saúde (Nutes) da Universidade Estadual da Paraíba, onde são realizadas impressões de biomodelos para planejamentos cirúrgicos. As tomografias afetadas por artefatos metálicos necessitam de correção antes do processo de impressão, esta intervenção realizada de forma manual implica em demora excessiva para entrega dos biomodelos. O desenvolvimento da solução proposta baseia-se no método de correção de sinograma que, de acordo com Mouton et al (2013) e Gjesteby (2016), é o método mais difundido para redução de artefatos metálicos e faz uso da técnica de interpolação linear para correção dos dados corrompidos. Objetivando validar a preferência pelo uso da interpolação linear no estado da arte, foram implementadas outras técnicas interpolativas as quais foram submetidas a avaliação; Primeiro por meio de simulações e depois via fomulário para avaliação qualitativa, na qual foram aplicados testes estatísticos. Os resultados obtidos ratificam o uso da interpolação linear como melhor opção para reconstrução de dados corrompidos pelos artefatos metálicos.
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Книги з теми "Tomogram images"

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Mohsen, Farsad, and Mansi Luigi, eds. PET-CT beyond FDG: A quick guide to image interpretation. Berlin: Springer, 2010.

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Fanti, Stefano, Mohsen Farsad, and Luigi Mansi. PET-CT Beyond FDG: A Quick Guide to Image Interpretation. Springer, 2011.

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Altshuler, David, Jason A. Heth, and Nicholas J. Szerlip. Skull Tumors. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190696696.003.0023.

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The diagnostic and treatment approach for patients with skull lesions begins with a thorough history and physical and careful attention to anatomic localization. The patient’s history and exam findings can inform a preliminary differential diagnosis, which may be broadly divided into benign and malignant processes. Based on a preliminary assessment, appropriate neuro-imaging involving magnetic resonance, computed tomograph, and/or vascular modalities may be pursued. Characteristic image findings may further refine a differential. While conservative management may be indicated for the most assuredly benign lesions, surgery is appropriate for cases involving compression of neural structures, deformity, pain or when a tissue diagnosis is required.
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Частини книг з теми "Tomogram images"

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Oswald, H. "A Medical Workstation for Three-Dimensional Display of computed Tomogram Images." In Computer Assisted Radiology / Computergestützte Radiologie, 565–71. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-52247-5_89.

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Jan, J., B. Gabrhel, J. Haluzíková, P. Kilián, R. Kubák, and I. Provazník. "Comparison of different approaches to suppress speckles in ultrasonic tomograms." In Computer Analysis of Images and Patterns, 657–63. Berlin, Heidelberg: Springer Berlin Heidelberg, 1993. http://dx.doi.org/10.1007/3-540-57233-3_88.

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Pommert, A., M. Bomans, U. Tiede, and K. H. Höhne. "Simulation Studies for Quality Assurance of 3D-Images from Computed Tomograms." In Medical Images: Formation, Handling and Evaluation, 323–30. Berlin, Heidelberg: Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-77888-9_12.

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Kawata, Satoshi, and Jack Sklansky. "Elimination of Nonpivotal Plane Images from X-ray Motion-tomograms." In Computer Assisted Radiology / Computergestützte Radiologie, 271–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-52247-5_44.

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Xu, Xiao-Ping, Christopher Page, and Niels Volkmann. "Efficient Extraction of Macromolecular Complexes from Electron Tomograms Based on Reduced Representation Templates." In Computer Analysis of Images and Patterns, 423–31. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-23192-1_35.

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Desai, Shrinivas D., and Linganagouda Kulkarni. "Comprehensive Survey on Metal Artifact Reduction Methods in Computed Tomography Images." In Medical Imaging, 1281–302. IGI Global, 2017. http://dx.doi.org/10.4018/978-1-5225-0571-6.ch052.

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Over the past few years, medical imaging technology has significantly advanced. Today, medical imaging modalities have been designed with state-of-the-art technology to provide much better in-depth resolution, reduced artifacts, and improved contrast –to – noise ratio. However in many practical situations complete projection data is not acquired leading to incomplete data problem. When the data is incomplete, tomograms may blur, resolution degrades, noise increases and forms artifacts which is the most important factor in degrading the tomography image quality and eventually hinders diagnostic accuracy. Efficient strategies to address this problem and to improve the diagnostic acceptability of CT images are thus invaluable. This review work, presents comprehensive survey of techniques for minimization of streaking artifact due to metallic implant in CT images. Problematic issues and outlook for the future research are discussed too. The major goal of the paper is to provide a comprehensive reference source for the researchers involved in metal artifact reduction methods.
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Bharadwaj, Pushan, and S. Richard Underwood. "Nuclear medicine in heart failure." In Oxford Textbook of Heart Failure, edited by Andrew L. Clark, Roy S. Gardner, and Theresa A. McDonagh, 303–14. Oxford University Press, 2022. http://dx.doi.org/10.1093/med/9780198766223.003.0023.

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Nuclear medicine, sometimes known as molecular imaging, involves the characterization and measurement of biological processes in vivo using small amounts of radiolabelled tracers. It is the most sensitive imaging technique in routine use, providing images of nano- or even picomolar concentrations of the tracer. In patients with heart failure (HF), biological processes such as myocardial perfusion, metabolism (both fatty acid and glucose), injury (including necrosis and apoptosis), and innervation are relevant and can be imaged. The ideal tracer is a biological molecule labelled with an isotope of one of its constituent elements (carbon, oxygen, nitrogen, etc.), since the tracer will have biological properties identical to those of the natural compound. Such isotopes are positron emitters and are imaged by positron emission tomography (PET), which relies on detecting the synchronous 511-keV photons emitted in opposite directions when the positron annihilates with an electron in the surrounding tissue. More common tracers use foreign elements such as iodine or technetium bound to a pharmaceutical that provides useful biological properties. These radiopharmaceuticals usually emit single gamma photons that are imaged by a gamma camera, often using single photon emission computed tomography (SPECT) to produce tomograms or three-dimensional images. PET has some inherent advantages over SPECT, such as higher resolution and more reliable attenuation correction that simplifies quantification of the biological process being imaged. PET is however more expensive and, with the exception of fluorine-18, the very short-lived radionuclides have to be generated on site, requiring the additional expense of a cyclotron.
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Frühauf, M. "Chapter 4 A User Interface for 3D Reconstruction of Computer Tomograms or Magnetic Resonance Images." In Data Handling in Science and Technology, 31–37. Elsevier, 1990. http://dx.doi.org/10.1016/s0922-3487(08)70154-0.

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Тези доповідей конференцій з теми "Tomogram images"

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Lucet, Nathalie M., and Gary M. Mavko. "Images of rock properties estimated from a cross‐well tomogram." In SEG Technical Program Expanded Abstracts 1991. Society of Exploration Geophysicists, 1991. http://dx.doi.org/10.1190/1.1888918.

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Lucet, N., and G. Mavko. "Images of rock properties estimated from a crosswell seismic velocity tomogram." In 53rd EAEG Meeting. European Association of Geoscientists & Engineers, 1991. http://dx.doi.org/10.3997/2214-4609.201411000.

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Sakai, Kaoru, Osamu Kikuchi, Masafumi Takada, Natsuki Sugaya, and Shigeru Ohno. "Image improvement using image processing for scanning acoustic tomograph images." In 2015 IEEE 22nd International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA). IEEE, 2015. http://dx.doi.org/10.1109/ipfa.2015.7224357.

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Newell, J. C., D. Isaacson, D. G. Gisser, K. S. Cheng, and J. C. Goble. "Images from an adaptive current tomograph." In Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE, 1988. http://dx.doi.org/10.1109/iembs.1988.94514.

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Lam, Walter Y. H., Henry Y. T. Ngan, Peter Y. P. Wat, Henry W. K. Luk, Edmond H. N. Pow, and Tazuko K. Goto. "Novel geometric coordination registration in cone-beam computed Tomogram." In 2014 IEEE Applied Imagery Pattern Recognition Workshop (AIPR). IEEE, 2014. http://dx.doi.org/10.1109/aipr.2014.7041922.

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Stringhini, Rômulo Marconato, and Daniel Welfer. "Método Baseado em Morfologia Matemática e BM3D para Redução de Ruı́do em Imagens Dentais de TC de Baixa Radiação." In Anais do Simpósio Brasileiro de Computação Aplicada à Saúde. Sociedade Brasileira de Computação - SBC, 2019. http://dx.doi.org/10.5753/sbcas.2019.6255.

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O impacto em reduzir a dose de radiação em exames de tomogra- fia computadorizada (TC) está diretamente relacionado à qualidade das ima- gens. Tais imagens são degradadas por artefatos indesejáveis, conhecidos como ruı́do. Diante disso, para melhorar a qualidade destas imagens e fornecer um diagnóstico médico preciso, é necessário aplicar técnicas que sejam capazes de reduzir ruı́do. Neste artigo, é proposto um método para filtrar ruı́do em imagens dentais de TC de baixa radiação, utilizando operadores da morfologia matemática e filtragem Block-Matching 3D (BM3D). Os resultados do método proposto foram comparados com diversos filtros existentes e validados utili- zando as métricas PSNR, SSIM e MSE. Através de diversos experimentos, o método proposto demonstrou performance superior aos filtros analisados, re- duzindo ruı́do e preservando detalhes de forma mais satisfatória.
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Guo, Yan, and Bernd Rieger. "Image Fusion of X-Ray and Electron Tomograms." In 2018 25th IEEE International Conference on Image Processing (ICIP). IEEE, 2018. http://dx.doi.org/10.1109/icip.2018.8451118.

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Westman, Erik C., Maureen M. Foss, and Earle M. Williams. "Comparison of stress distribution images generated withP, SH, andSVvelocity tomograms." In SEG Technical Program Expanded Abstracts 1994. Society of Exploration Geophysicists, 1994. http://dx.doi.org/10.1190/1.1932152.

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Southekal, Sudeepti S., Martin Purschke, Sang-June Park, Sachin S. Junnarkar, Jean-Francois Pratte, Sean P. Stoll, David J. Schlyer, Craig L. Woody, and Paul Vaska. "Quantitative Image Reconstruction for the RatCAP PET Tomograph." In 2006 IEEE Nuclear Science Symposium Conference Record. IEEE, 2006. http://dx.doi.org/10.1109/nssmic.2006.356445.

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Sauer, Ken, and Bede Liu. "Statistical Refinement Of Transmission Computed Tomograms In High Photon Counting Noise." In 1989 Symposium on Visual Communications, Image Processing, and Intelligent Robotics Systems, edited by William A. Pearlman. SPIE, 1989. http://dx.doi.org/10.1117/12.970104.

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Звіти організацій з теми "Tomogram images"

1

Virador, Patrick R. G. Image reconstruction for a Positron Emission Tomograph optimized for breast cancer imaging. Office of Scientific and Technical Information (OSTI), April 2000. http://dx.doi.org/10.2172/772147.

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