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 20 for “"4D CT"”.
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4D CT based analysis of knee kinematics
Introduction: Total Knee Arthroplasty, which is the last resort of treatment for osteoarthritis, is aimed at restoring the functional anatomy of the knee. Despite the recent improvements in surgical techniques, limited range of motion, postoperative instability and malalignment still hinder the …
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Evaluation of Artifacts In Experimental Cine 4D Ct Acquisition Methods
<p>Four-dimensional computed tomography (4D CT) has increased the accuracy of radiation treatment planning for patients in whom the extent of target motion is large. 4D CT has become a standard of care for radiation treatment simulation, allowing decreased motion artifacts and increased …
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Evaluating and Improving 4D-CT Image Segmentation for Lung Cancer Radiotherapy
… due to the influence of respiratory motion. 4D-CT imaging is capable of improving image quality of thoracic target volumes influenced by respiratory motion. 4D-CT-based treatment planning strategies requires highly accurate anatomical segmentation of tumour volumes for radiotherapy treatment …
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Evaluation of Deformable Image Registration For Improved 4D Ct-Derived Ventilation For Image Guided Radiotherapy
… treatment planning to identify regions for functional avoidance. This image-guided radiotherapy (IGRT) strategy may reduce the injury and/or functional loss following thoracic radiotherapy. 4D computed tomography (CT), developed for radiotherapy treatment planning, is a relatively new imaging …
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Development and application of a 4-dimensional Computed Tomography simulator
… of a 4-Dimensional Computed Tomography (4D CT) simulation program. The simulation is used to understand and quantify the sources of image artifacts that arise from irregular patient breathing during 4D CT. Performance of the simulation is validated by comparing the simulation results with …
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Thoracic Radiotherapy Treatment Planning With Cine Pet/Ct
… planning. Four-dimensional computed tomography (4D-CT) is a useful tool to image tumor motion during normal respiration. Treatment margins can be reduced by targeting the motion path of the tumor. The expense and complexity of 4D-CT, however, may be cost-prohibitive at some facilities. We …
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Thoracic Target Volume Delineation Using Various Maximum-Intensity Projection Computed to mography Image Sets For Stereotactic Body Radiation Therapy
… of four-dimensional computed tomography (4D-CT) has allowed us to determine how a tumor moves with respiration for each individual patient. Using information acquired during a 4D-CT scan, we can define the target, visualize motion, and calculate dose during the planning phase of the …
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Improvements In Four-Dimensional and Dual Energy Computed to mography
<p>Dual energy and 4D computed tomography (CT) seek to address some of the limitations in traditional CT imaging. Dual energy CT, among other purposes, allows for the quantification and improved visualization of contrast materials, and 4D CT is often used in radiation therapy applications as it …
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Radiomics of Nsclc: Quantitative Ct Image Feature Characterization and Tumor Shrinkage Prediction
<p>Radiomics is the high-throughput extraction and analysis of quantitative image features. For non-small cell lung cancer (NSCLC) patients, radiomics can be applied to standard of care computed tomography (CT) images to improve tumor diagnosis, staging, and response assessment.</p> <p>The first …
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Implementation,Validation and Application of an Automated Motion Correction Algorithm in Hepatic Perfusion CT for Image-Guided Radiotherapy
Functional imaging holds promise in guiding, evaluating and predicting efficacy of cancer treatment. Perfusion imaging provides high resolution functional information generated by applying a model to a dynamic series of contrast enhanced anatomical images. The objectives of this thesis are: 1) to …
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A Composite Material-based Computational Model for Diaphragm Muscle Biomechanical Simulation
… a patient specific biomechanical model that predicts the deformation field of the diaphragm muscle during respiration. The first part of the project involved developing an accurate and adaptable micro-to-macro mechanical approach for skeletal muscle tissue modelling for application in a FE solver. …
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A phantom based evaluation on the effects of patient breathing motion on Stereotactic Body Radiotherapy treatment volumes
… inside the lung area of the phantom. Introduction: Expansion margins are added to clinical target volumes contoured by Oncologists in order to safeguard against under- or over-treatment of the target volume. They are designed to account for errors during setup, inaccuracies on the linear …
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4D Study of Thoracic Cancer Radiation Treatment
… to ensure coverage of the tumor. Reduction of the volume of normal tissue irradiation while maintaining tumor coverage is used to accomplish this goal. The application of 4D CT imaging to radiotherapy treatment planning is an active area of research with the goal to reduce the required …
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Current Concepts in the Aetiology, Pathogenesis and Management of Kienbock’s Disease
… has been debated. The disease encompasses a spectrum of age and gender but is classically considered to affect young-to-middle-aged male manual laborer’s. Both mechanical and vascular factors play a role in disease aetiology, and it is likely that a critical combination is important. Alteration …
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Development of Five-dimensional Magnetic Resonance Imaging (5D-MRI) for Radiation Therapy
… treatment planning uses 2D X-ray or 3D CT images to assist the delineation of tumor volumes and OARs, often under free-breathing condition. In modern radiation therapy, four-dimensional (4D) imaging is the state-of-art technique for imaging respiratory motion of thoracic and abdominal …
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Optimization of Image Guided Radiation Therapy for Lung Cancer Using Limited-angle Projections
… target localization and tracking. With an objective to improve the accuracy of on-board imaging for lung cancer patients, the dissertation work focuses on the investigations of using limited-angle on-board x-ray projections for image guidance. The limited-angle acquisition enables scan time and …
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Intensity Modulated Proton Therapy Optimization Under Uncertainty: Field Misalignment and Internal Organ Motion
… motion. These uncertainties can greatly impact the quality of clinical treatment. Therefore, this dissertation aims to investigate different optimization methods for treatment planning and to handle a variety of uncertainties in IMPT. First, to solve the fluence map optimization (FMO) problem …
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Improvements In Robustness and Optimality of Intensity-Modulated Proton Therapy Plans For Lung Cancer Patients With 4-Dimensional Robust Optimization
… motion in treatment planning. The primary objective of this research was to develop a novel four-dimensional robust optimization (4DRO) method and find an appropriate optimization strategy to make IMPT dose distributions less sensitive to both respiratory motion as well as to setup and range …
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Alternating Minimization Algorithms for Dual-Energy X-Ray CT Imaging and Information Optimization
… contributes toward solutions to two distinct problems linked through the use of common information optimization methods. The first problem is the X-ray computed tomography (CT) imaging problem and the second is the computation of Berger-Tung bounds</p><p>for the lossy distributed source …
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On Motion Parameterizations in Image Sequences from Fixed Viewpoints
… addresses the problem of parameterizing object motion within a set of images taken with a stationary camera. We develop data-driven methods across all image scales: characterizing motion observed at the scale of individual pixels, along extended structures such as roads, and whole image …