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 26 for “"cone-beam CT"”.
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Motion binning in cone-beam CT without a prior Model
Cone-beam CT (CBCT), used to reduce setup error in radiotherapy, takes a sequence of about 670 two-dimensional X-rays acquired in a circular arc around the patient over two minutes and reconstructs a three-dimensional volume from these projections. Consequently, when tissues move significantly …
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Factors Influencing Contrast Resolution of Cone Beam CT Using the CB MercuRay
<p><strong>Introduction:</strong> Cone Beam Computed Tomography (CBCT) has an application in all dental specialties. CBCT is an aid in implant dentistry to evaluate anatomical landmarks in both quality and quantity. Hounsfield Unit (HU) values represent a grayscale that is standardized on CT …
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Improvement of image reconstruction speed with GPU in cone beam CT breast imaging
… women in the United States. Our group is constructing a dedicated cone beam breast CT (CBCT) system to provide true 3D image to improve the screening and diagnostic of breast cancer. Our result shows that dedicated CBCT out-perform a lot than conventional CT when detecting micro-calcification …
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IMAGE-BASED RESPIRATORY MOTION EXTRACTION AND RESPIRATION-CORRELATED CONE BEAM CT (4D-CBCT) RECONSTRUCTION
… tumor targets during radiotherapy. Thus, extracting respiratory motion is a key task in radiation therapy planning. Respiration-correlated or four-dimensional CT (4DCT) imaging techniques have been recently integrated into imaging systems for verifying tumor position during treatment and …
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Development of a Fully Automated Al System for Skeletal Maturity Assessment Using Cone Beam CT
… the timing of interventions such as myofunctional appliances and orthognathic surgery. Clinicians look to biological markers, such as the cervical vertebrae and the spheno-occipital synchondrosis to perform such assessment, and automation of this process would greatly assist clinicians with …
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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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Spatial Resolution Analysis of a Variable Resolution X-ray Cone-beam Computed Tomography System
<p>A new cone-beam computed tomography (CBCT) system is designed and implemented that can adaptively provide high resolution CT images for objects of different sizes. The new system, called Variable Resolution X-ray Cone-beam CT (VRX-CBCT) uses a CsI-based amorphous silicon flat panel detector …
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Development and Realization of the IGRT Inline Concept
… is described. An x-ray tube and a flat panel detector were installed along the treatment beam axis, such that the detector could not only be used for x-ray imaging of patients lying on the treatment couch, but also to measure the primary fluence of the therapy beam. The imaging system was …
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Assessment of Human Alveolar Bone Density by Using Volumetric CT Machine
… bone density in designated implants sites using cone-beam computed tomography (CBCT) and compared the measurements to those of quantitative computed tomography (QCT) and subjective bone density evaluation. Sixty-two designated implant sites in 9 human cadavers jaws were used. Indicator rods, 2 mm …
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Evaluation of target motion and determination optional treatment margins for prostate cancer treated with external beam radiotherapy on Halcyon
Background External beam radiotherapy (EBRT) is an important part of the treatment for prostate cancer. To account for organ motion and set-up error, margins are used in radiotherapy planning. These are essential for the delivery of safe and effective treatment. Aim and Setting To measure prostate …
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Compressed Sensing Based Image Restoration Algorithm with Prior Information: Software and Hardware Implementations for Image Guided Therapy
… restoration problem for handling missing structures in one image set with prior information, and it enhances the quality of the image and the anatomical information of the volume of the on-board computed tomographic (CT) with limited-angle projections. Through the use of the algorithm, prior …
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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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Detecting and Evaluating Therapy Induced Changes In Radiomics Features Measured From Non-Small Cell Lung Cancer to Predict Patient Outcomes
… from weekly 4-dimensional computed tomography (4DCT) images of non-small cell lung cancers (NSCLC) change during treatment and if those changes are prognostic for patient outcomes or dependent on treatment modality. Radiomics features are quantitative metrics designed to evaluate tumor …
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A Preclinical Study of Radiation-Induced Lung to xicity When Irradiating In A Strong Magnetic Field
… purpose of this work was to evaluate the effect of a strong, transverse magnetic field on the severity of radiation-induced lung damage in mice. This data can be used to support the safe clinical implementation of MRI-guided radiation therapy systems.</p> <p>Monte Carlo simulations and EBT3 …
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Algebraic Reconstruction Methods for Complex Geometry Components
Industrial CT has seen widespread adoption as an inspection technique due to its ability to resolve small defects and perform high-resolution measurements on complex structures in Non Destructive Testing (NDT). The majority of the commercial cabinet systems are capable of acquisition and …
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Comparison of Cone-Beam Computed Tomography (CBCT), Fan-Beam Computed Tomography (FBCT), and Low-Field Magnetic Resonance Imaging (MRI) for Detection of Equine Fetlock Lesions
Computed tomography (CT) and magnetic resonance imaging (MRI) have been increasingly applied to diagnosing lameness localised to the fetlock region in standing horses. A full understanding of the benefits and limitations of CT and MRI for detection of bone and soft tissue lesions is essential for …
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Robust Treatment Planning and Robustness Evaluation for Proton Therapy of Head and Neck Cancer
… approaches, which account for uncertainties directly into the plan optimization process, are able to generate high quality plans robust against uncertainties compared to a PTV margin expansion approach. During radiation treatment, patients are prone to present anatomical variations during the …
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Cone Beam Computerized Tomography Analysis of Haller cell : Prevalence and Clinical Significance.
<p><strong>Introduction</strong></p> <p>Albert von Haller described Haller cells (HC) as anterior ethmoidal cells along orbital floor and above maxillary sinus ostium. Location of HC could predispose maxillary sinusitis<strong> </strong>(MS)<strong> </strong></p> <p><strong>Purpose of the Study …
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