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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 264 for “"Computed tomography (CT)"”.
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QUANTIFYING RADIATION INDUCED CORTICAL BONE LOSS USING COMPUTED TOMOGRAPHY (CT) IMAGING
Bone fracture is a major complication of radiation therapy (RT). The etiology of RT-induced fractures is unclear, but likely involves bone damage and deterioration. Unfortunately, there remains a paucity of quantitative data on structural bone changes after exposure to RT. The primary goal of this …
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Automatic interpretation of computed tomography (CT) images for hardwood log defect detection
… interpretation system for the automatic detection of internal hardwood log defects. The goal of the research is that such a system should not only be able to identify and locate internal defects of hardwood logs using computed tomography (CT) imagery, but also should be able to accommodate …
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Computed tomography (CT) head studies in a district emergency department: a focused study of CT related imaging and analysis of current practice
Introduction: The South African population has a significant emergency burden of disease. In South Africa, immediate access to computed tomography (CT) imaging may not always be available. Globally, the number of all imaging studies is increasing annually. Due to access challenges patients …
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Numerical simulation of human breathing and particle transport through a CT-based pulmonary airway geometry
Chronic respiratory illness afflicts more than a billion people worldwide. In recent years computational fluid dynamics (CFD) has been established as a paramount tool for studying treatments of respiratory illnesses. This work investigates physiologically appropriate, lobar-specific boundary …
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Identification and reconstruction of bullets from multiple x-rays
The 3D shape and position of objects inside the human body are commonly detected using Computed Tomography (CT) scanning. CT is an expensive diagnostic option in economically disadvantaged areas and the radiation dose experienced by the patient is significant. In this dissertation, we present a …
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Morphological Analysis of Changes in the Thoracic Skeleton with Age and Gender
… variations with age and gender are expected to affect thoracic injury mechanisms and tolerance. The objective of this research was to quantify the age and gender-specific variations in the thoracic skeletal morphology for both genders and across the entire age spectrum (ages 0-100). A …
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Selection of Step Size for Total Variation Minimization in CT
<p>Medical image reconstruction by total variation minimization is a newly developed area in computed tomography (CT). In compressed sensing literature, it hasbeen shown that signals with sparse representations in an orthonormal basis may be reconstructed via l1-minimization. Furthermore, if an …
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A Manufacturing Process for Single Micron Resolution Optical Gratings Used in X-ray Computed Tomography
X-ray Computed Tomography (CT) is a process that produces three-dimensional x-ray images, allowing for better diagnosis and analysis of complex internal medical conditions. New advances in the optical techniques used in this process promise to produce better results while reducing patient risk. One …
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A Complete Dosimetric Model of the Gamma Knife Perfexion Using Penelope Monte Carlo Codes
… irradiate targets in the head. It uses 192 high-activity Cobalt-60 sources collimated to a common focus to impart radiological damage to the target structure while minimizing dose to adjacent healthy tissue. Tungsten collimators are organized into eight sectors of 24 sources each; each sector can …
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Improvements on low-cost high-resolution CT system
Computed tomography (CT) is an x-ray based inspection technique used to analyze the three dimensional structure of an object. The goal of this thesis is to show that good CT image quality can be achieved with low cost CT systems while maintaining high resolution and keeping the collection time for …
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Area Based Fan Beam Projection Model for Computed Tomography
<p>Computed tomography (CT) is image reconstruction of objects using computer processed transmission or reflection data, usually referred to as projection data, from x-ray scanning. This projection data is often modeled using line integrals, but x-rays are of finite width in reality, so the …
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Image-Based Morphological Modeling of Soft and Bony Tissue with Applications in Prognostics and Medical Device Design
… of bony and soft tissue anatomy from computed tomography (CT) and magnetic resonance 1 images is used to quantify shape and density variation of structures and to associate these variations with existing abnormalities and dysfunctions for disease prognosis and prediction of injury …
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Development of image-based surgical planning software for bone-conduction implants
The BONEBRIDGE bone-conduction device is used to treat conductive and mixed hearing losses. The size of its floating mass transducer (FMT) can preclude implantation in certain anatomies, necessitating comprehensive surgical planning. Current techniques are time consuming and difficult to transfer …
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Generating Synthetic X-rays Using Generative Adversarial Networks
… are available. Traditional methods are restricted to 3-D inputs such as meshes or Computed Tomography (CT) scans. We create custom synthetic X-ray datasets using a custom generator capable of creating RGB images, point cloud images, and 2-D pose images. We create a dataset using natural hand …
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Visualizing fluidized beds with X-rays
… minimum fluidization velocity experiments, X-ray computed tomography (CT), X-ray stereography, and particle tracking to fluidized beds of glass beads, ground walnut shell, and ground corncob operating with a variety of flow conditions. 3-D local, time-averaged gas holdup is calculated from CT …
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Image guidance in cardiac electrophysiology
Cardiac arrhythmias are characterized by a disruption or abnormal conduction of electrical signals within the heart. Treatment of arrhythmias has dramatically evolved over the past half-century, and today, minimally-invasive catheter-based therapy is the preferred method of eliminating arrhythmias. …
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A square root analog to digital converter to optimally convert photonic signals for computed tomography
… converter (ADC) with a square root transfer function can quantize photonic signals with LSB size kept constant with respect to the photon shot noise. In imaging applications, this can greatly reduce the number of bits needed to characterize a signal compared to a linear ADC without detrimental …
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Unsupervised discovery of emphysema subtypes in a large clinical cohort
… is one of the hallmarks of Chronic Obstructive Pulmonary Disease (COPD), a devastating lung disease often caused by smoking. Emphysema appears on Computed Tomography (CT) scans as a variety of textures that correlate with the disease subtypes. It has been shown that the disease subtypes …
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Hybrid Spectral Micro-CT: System Implementation, Exposure Reduction, K-edge Imaging Optimization, and Content Management
Spectral computed tomography (CT) has proven an important development in biomedical imaging, yet there are several limitations to this nascent technology. Near-term implementation of spectral CT imaging can be enhanced using a hybrid architecture that integrates a narrow-beam spectral 'interior' …
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