Search results for "tomography"
showing 10 items of 2332 documents
Damage accumulation in a carbon/epoxy composite : Comparison between a multiscale model and computed tomography experimental results
2012
International audience; High-resolution computed tomography has been carried out for carbon/epoxy laminates loaded in situ to failure. The experimental data allows major damage mechanisms to be quantified in 3D, in an unambiguous and mechanically representative way, where previous experimental analysis is limited. A multi-scale model that predicts damage accumulation in tensile loaded composites is compared to the experimental analysis, to validate the underpinning assumptions within the model and overall performance. The model considers the random nature of fibre-strengths, stress transfer resulting from fibre breaks, fibre/matrix debonding and viscosity of the matrix. Assumptions within t…
Data for: Synthesis and evaluation of 89Zr-labeled and long-lived GLP-1 receptor agonists for PET imaging
2020
Appendix B. PET imaging 3D rendered images. 1. PET 3D of 4-89Zr 2. PET 3D of 5-89Zr
Low in vivo brain glucose consumption and high oxidative stress in accelerated aging
2009
AbstractThe validity of the free radical theory of aging has been recently questioned. Our aim was to test whether there is oxidative stress in tissues critically involved in accelerated aging (senescence-accelerated mice, SAM) and whether this correlates with lower glucose consumption in vivo and behavioural tests. Positron emission tomography shows that brains of old SAM-prone animals consume less glucose than young ones. Behavioural characteristics, mitochondrial peroxide production, and damage in both the central nervous system and bone marrow stem cells also indicate that SAM-prone animals age faster than SAM-resistant ones. Our results support the role of the free radical theory of ag…
Active contour algorithm with discriminant analysis for delineating tumors in positron emission tomography.
2019
Abstract In the context of cancer delineation using positron emission tomography datasets, we present an innovative approach which purpose is to tackle the real-time, three-dimensional segmentation task in a full, or at least nearly full automatized way. The approach comprises a preliminary initialization phase where the user highlights a region of interest around the cancer on just one slice of the tomographic dataset. The algorithm takes care of identifying an optimal and user-independent region of interest around the anomalous tissue and located on the slice containing the highest standardized uptake value so to start the successive segmentation task. The three-dimensional volume is then…
The diagnostic possibilities of Positron Emission Tomography (PET)
2014
Se describen los principios de la tomografía por emisión de positrones (PET) como procedimiento diagnóstico de reciente introducción en el campo de las Ciencias de la Salud. Las aplicaciones clínicas principales se dan en un grupo concreto de especialidades: la cardiología, neurología, psiquiatría y sobre todo la oncología. La tomografía por emisión de positrones es una técnica de diagnóstico por la imagen no invasiva de uso clínico. Se trata de una excelente herramienta para el estudio de la estadificación y la posible malignización de los tumores de cabeza y cuello, la detección de metástasis y linfoadenopatías no valorables clínicamente, así como para el diagnóstico de recidivas tumorale…
Immunohistochemical expression of glucose transporter 1 in keratin-producing odontogenic cysts
2016
Background: Keratin-producing odontogenic cysts (KPOCs) are a group of cystic lesions that are often aggressive, with high rates of recurrence and multifocality. KPOCs included orthokeratinised odontogenic cyst (OOC) and parakeratotic odontogenic cysts, which are now considered true tumours denominated keratocystic odontogenic tumours (KCOTs). GLUT1 is a protein transporter that is involved in the active uptake of glucose across cell membranes and that is overexpressed in tumours in close correlation with the proliferation rate and positron emission tomography (PET) imaging results. Methods: A series of 58 keratin-producing odontogenic cysts was evaluated histologically and immunohistochemi…
An Unusual Presentation of Zollinger-Ellison Syndrome
2013
Abstract Zollinger-Ellison syndrome is an often progressive, persistent and frequently life-threatening disease, described for the first time as characterized by ulceration of the upper jejunum, hypersecretion of gastric acid and non-beta islet cell tumors of the pancreas; this syndrome is due to the hypersecretion of gastrin. We report a case of Zollinger-Ellison syndrome presenting as severe esophagitis evolving in stenosis, which demonstrates how a delayed diagnosis may induce risk of disease spreading. In this setting new diagnostic approaches, such as somatostatin receptor scanning and positron emission tomography with 68 Ga-labeled octreotide, could be particularly useful, as well as …
The appropriate and justified use of medical radiation in cardiovascular imaging: a position document of the ESC Associations of Cardiovascular Imagi…
2014
The benefits of cardiac imaging are immense, and modern medicine requires the extensive and versatile use of a variety of cardiac imaging techniques. Cardiologists are responsible for a large part of the radiation exposures every person gets per year from all medical sources. Therefore, they have a particular responsibility to avoid unjustified and non-optimized use of radiation, but sometimes are imperfectly aware of the radiological dose of the examination they prescribe or practice. This position paper aims to summarize the current knowledge on radiation effective doses (and risks) related to cardiac imaging procedures. We have reviewed the literature on radiation doses, which can range …
CT-Densitometrie zur Analyse der statischen Druckvolumenkurve der Lunge bei experimentell induziertem Lungenschaden
2005
Purpose: To study quantitative changes of lung density distributions when recording in- and expiratory static pressure-volume curves by single slice computed tomography (CT). Materials und Methods: Static in- and expiratory pressure volume curves (0 to 1000ml, increments of 100ml) were obtained in random order in 10 pigs after induction of lung damage by saline lavage. Simultaneously, CT acquisitions (slice thickness 1 mm, temporal increment 2 s) were performed in a single slice (3 cm below the carina). In each CT image lung segmentation and planimetry of defined density ranges were achieved. The lung density ranges were defined as: hyperinflated (-1024 to -910 HU), normal aerated (-910 to …
Evaluation of [11C]Metergoline as a PET Radiotracer for 5HTR in Nonhuman Primates
2010
Metergoline, a serotonin receptor antagonist, was labeled with carbon-11 in order to evaluate its pharmacokinetics and distribution in non-human primates using positron emission tomography. [{sup 11}C]Metergoline had moderate brain uptake and exhibited heterogeneous specific binding, which was blocked by pretreatment with metergoline and altanserin throughout the cortex. Non-specific binding and insensitivity to changes in synaptic serotonin limit its potential as a PET radiotracer. However, the characterization of [{sup 11}C]metergoline pharmacokinetics and binding in the brain and peripheral organs using PET improves our understanding of metergoline drug pharmacology.