Global ETD Search
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 41 for “"optical tomography"”.
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Isogeometric Approach to Optical Tomography
Optical Tomography is an imaging modality that enhances early diagnosis of disease through use of harmless Near-Infrared rays instead of conventional x-rays. The subsequent images are used to reconstruct the object. However Optical Tomography has not been effectively utilized due to the complicated …
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Developing High-Density Diffuse Optical Tomography for Neuroimaging
… function. A decade ago, there was hope that optical imaging would be able to fill this role, as it combined fMRI's ability to construct cortical maps with EEG's portable, cap-based systems. However, early optical systems had poor imaging performance, and the momentum for the technique slowed. …
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Near-Field Scanning Optical Tomography: Theory and Modalities
Other possible modalities of NSOT are investigated. An experimental configuration with three-dimensional volumetric scan of the probe is studied for the possibility of a tomographic imaging with a fixed-angle illumination. Alternatively, a broadband illumination with one fixed angle or a limited …
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Diffuse Optical Tomography Methods for Imaging the Developing Brain
<p>Diffuse optical imaging (DOI) is a portable imaging modality that provides the ability to perform early and continuous monitoring of brain function in infants. Its methodology overcomes many of the technical and logistical challenges of performing magnetic resonance imaging (MRI) investigations …
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Investigating Cerebral Function in Neonates Using Diffuse Optical Tomography
… and understand brain injury in patients. Diffuse optical tomography (DOT) is a promising imaging technique that is non-invasive, portable and relatively simple to operate. In this thesis, I describe the development and design of DOT headgear for neonates and subsequently apply this in neonatal …
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Purely optical tomography : atlas-based reconstruction of brain activation
Diffuse Optical Tomography (DOT) is a relatively new method used to image blood volume and oxygen saturation in vivo. Because of its relatively poor spatial resolution (typically no better than 1-2 cm), DOT is increasingly combined with other imaging techniques, such as MRI, fMRI and CT, which …
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Dynamic Digital Optical Tomography for Cancer Imaging and Therapy Monitoring
Diffuse optical tomography is a non-invasive imaging technique that uses near-infrared light to create three-dimensional images of tissue. This dissertation presents the design and validation of an instrument for rapid optical imaging using digital detection techniques. In addition to a detailed …
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Functional Imaging the Neonatal Brain with Wearable Diffuse Optical Tomography
… infant populations. Non-invasive and wearable optical brain imaging technologies may allow for the cot-side study of newborn infants in clinical settings. This has particularly important implications for preterm infants in intensive care, for whom traditional neuroimaging techniques are not …
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Ultrasound-encoded optical tomography and time-reversed ultrasonically encoded optical focusing
Ultrasound modulated optical tomography is a developing hybrid imaging modality that combines high optical contrast and good ultrasonic resolution to image soft biological tissue. We developed a photorefractive crystal-based, time-resolved detection scheme with the use of a millisecond long …
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Development and Applications of Laminar Optical Tomography for In Vivo Imaging
Laminar optical tomography (LOT) is an optical imaging technique capable of making depth-resolved measurements of absorption and fluorescence contrast in scattering tissue. LOT was first demonstrated in 2004 by Hillman et al [1]. The technique combines a non-contact laser scanning geometry, similar …
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Measurement of gas bubbles in a vertical water column using optical tomography.
… an investigation into the application of optical fibre sensors to a tomographic imaging system for use with gas/water mixtures. Several sensing techniques for measurement of two component flow using non-intrusive techniques are discussed and their relevance to tomographic applications …
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Application of neural networks to the reconstruction of diffuse optical tomography neuroimages
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2026-05-01
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Computational Methods for Improved Interpretation of High-Density Diffuse Optical Tomography Data
High-density diffuse optical tomography (HD-DOT) is a promising neuroimaging technique that can be used to produce three-dimensional reconstructions of brain activity. However, analysis methods applied to this data are not yet standardised, and often do not take advantage of the higher data …
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Applications of U-net to diffuse optical tomography data: Image reconstruction and superresolution
Di use optical tomography (DOT) is being investigated for effective functional brain imaging. It serves as a cheaper, less bulky and safer alternative to fMRI imaging which is the current gold standard. However, due to the complicated nature of the system, analytical reconstruction approaches begin …
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Quantification of the spatial structure and temporal variability of Earth's exosphere using optical tomography
… statistical data analysis approach using tomography, and technique validation based on synthetic data. The mission concept yields global quantification of exospheric structure with unprecedented spatial and temporal resolution, thereby enabling significant advances in the coupling of …
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Study of the Term Neonatal Brain Injury with combined Diffuse Optical Tomography and Electroencephalography
… describes the application of combined diffuse optical tomography (DOT) and electroencephalography (EEG) in the investigation of neonatal term brain injury. With hypoxic ischaemic encephalopathy (HIE) and perinatal stroke being the most frequent contributors to brain injury in the term neonatal …
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A multimodal breast cancer imaging system using coregistered dynamic diffuse optical tomography and digital breast tomosynthesis
Diffuse optical tomography (DOT) is an emerging noninvasive functional imaging method for breast cancer diagnosis and neoadjuvant chemotherapy monitoring. In particular, the multimodal approach of combining DOT with x-ray digital breast tomosynthesis (DBT) is especially synergistic as DBT prior …
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Investigating the Impact of Sleep on Early Dynamic Functional Connectivity: A High-Density Diffuse Optical Tomography Study in Term and Preterm Neonates
… and preterm neonates using High-Density Diffuse Optical Tomography (HD-DOT), a functional near-infrared spectroscopy (fNIRS) technology. The goal of this work was to clarify the relationship between neonatal sleep states, gestational age (GA), and functional brain development. Shedding light on …
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Simultaneous Integrated Functional Magnetic Resonance Imaging and Optical Tomography in the Near Infrared Spectrum (Sinfonis) for Studying Hemodynamic and Neuronal Responses in the Human Brain
The hemodynamic responses reconstructed from DOT have shown reasonably good consistency with that of the BOLD fMRI result. It has been discovered from the correspondence between the two results that the change in oxyhemoglobin concentration may also play a secondary role in the BOLD signal. …
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Enabling Biomedical Imaging Diagnostics using Optical Methods
<p>This thesis work applies optical schemes to existing biomedical imaging techniques to improve the performance of present state-of-the-art biomedical imagers, and is in two parts. In the first part, a fast and simple optical time-gate scheme for counting single photons is presented. The gate is …
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