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 22 for “"deformable image registration"”.
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Improving Quantitative Treatment Response Monitoring With Deformable Image Registration
… hypothesis of this study is that more accurate image registration will lead to improved quantitation of tissue response to RT with 18F-FDG PET/CT. Employing an in-house developed “demons” based deformable image registration algorithm, pre-RT tumor and parotid gland volumes can be more accurately …
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Evaluation of Deformable Image Registration For Improved 4D Ct-Derived Ventilation For Image Guided Radiotherapy
… studies have demonstrated the use of physiologic images in radiation therapy 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), …
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Investigation of Deformable Image Registration Based Lung Ventilation Mapping for Radiation Therapy Using a Hybrid Hyperpolarized Gas MRI Technique
… function tests such as spirometry, ventilation images provide a regional measure of pulmonary function. Conventional methods for lung ventilation imaging include gamma camera scintigraphy and positron emission tomography scan after inhaling a gaseous radionuclide, as well as hyperpolarized (HP) …
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Evaluation of optimal control-based deformable registration model
The deformable image registration is central to many challenges in medical imaging applications. The basic idea of the deformable image registration problem is to find an approximation of a reasonable deformation which transforms one image to match another based on a chosen similarity measure. A …
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Exploring the Role of GD-EOB-DTPA (Primovist®) MRI in Liver Stereotactic Body Radiation Therapy Accuracy
… the number of treatments, motion management, and image guidance can vary across cancer centers. Due to this, the delivery accuracy can also vary across different practices of liver SBRT implementation. The Primovist®-enhanced MRI allows for the direct visualization of the radiation deposition …
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Ai-Enabled Online Plan Adaptation For Mr-Guided Stereotactic Ablative Radiotherapy (Sabr) of Head and Neck Cancer
… by radiation oncologists, and multimodality images (CT, PET, and MRI) were included to improve the contouring accuracy. We found that more than 95% of the automatically generated GTVs were clinically acceptable.</p> <p>Next, we automated the deformable image registration between planning and …
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4D Study of Thoracic Cancer Radiation Treatment
… irradiation and improve the tumor coverage. Deformable image registration holds the key to link the information of two images at various phases. The major purpose of this study is to develop and validate the optical flow method (OFM), a method of deformable image registration by which the …
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Diffeomorphic image registration with applications to deformation modelling between multiple data sets
Over last years, the diffeomorphic image registration algorithms have been successfully introduced into the field of the medical image analysis. At the same time, the particular usability of these techniques, in majority derived from the solid mathematical background, has been only quantitatively …
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Improving Cervical Cancer Nodal Boost Radiation Therapy By Quantifying Uncertainties and Exploring Advanced Radiation Therapy Modalities
… radiation therapy (IMRT) are used. We used deformable image registration algorithms to volumetrically sum dose for the bladder and rectum and created a voxel-by-voxel validation method. The mean error in deformable image registration results of all voxels within the bladder and rectum were 5 …
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Intranuclear strain measured by iterative warping in cells under mechanical and osmotic stress
… Therefore, a hybrid imaging and model based image registration technique has been developed to enabled us to explore links between biomechanical and biochemical signaling within individual cells. The hybrid technique uses an iterative warping deformable image registration to measure …
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Applications of machine learning in nuclear imaging and radiation detection
… interpreting and analyzing 3D medical radiation images automatically. A method is developed to identify and quantify deformable image registration (DIR) errors from lung CT scans for quality assurance (QA) purposes. The method includes the process of preparing a CT scan dataset for machine …
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Registration of images containing rigid structures using deformable models and its medical application
This thesis presents research and development in registration of images containing rigid structures using deformable models. In the existing methods of deformable image registration, the feature based methods using purely interpolation are often used under the assumption that all parts of the image …
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Towards understanding multiscale articular cartilage mechanics
… testing systems capable of acquiring 3-D images of tissue subjected to controlled mechanical conditions. By comparing tissue volumes in different mechanical states, micro-scale deformation can be calculated. This work focused on the extension of the current analysis toolkit of such …
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Improving Cone-Beam Computed Tomography Based Adaptive Radiation Therapy with Deep Learning
… challenge involves generating synthetic CT (sCT) images that retain CBCT anatomy while maintaining CT image quality. Clinically used sCT is typically obtained through deformable image registration (DIR) between pre-planning CT (pCT) and CBCT; however, this method often inadequately preserves CBCT …
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Quantifying, Understanding and Predicting Differences Between Planned and Delivered Dose to Organs at Risk in Head & Neck Cancer Patients Undergoing Radical Radiotherapy to Promote Intelligently Targeted Adaptive Radiotherapy
… (OARs) were computed from daily megavoltage CT image guidance scans, using an open-source deformable image registration package (Elastix). Toxicity data were prospectively collected. Relationships between DP, DA and late toxicities were investigated with univariate, and logistic regression …
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Quantitative pathophysiology in rabbit models of early onset scoliosis and expansion thoracoplasty
… of regional specific volume distributions via CT deformable-image-registration and through estimation of dynamic heterogeneity via inverse modeling of the respiratory input impedance, and 4) to evaluate the response of biological mechanisms in the alveolar microstructure in these rabbits through …
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Integration of Biomedical Imaging and Translational Approaches For Management of Head and Neck Cancer
… proper standardization of the immobilization and image acquisition techniques, we can achieve high geometric accuracy. These images can then be used to monitor the shrinkage of tumors during RT and optimize the clinical target volumes accordingly. Our results also showed that this MR-guided dose …
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Improving Dose-Response Correlations For Locally Advanced Nsclc Patients Treated With Imrt Or Pspt
… tackle these limitations, we developed advanced deformable image registration (DIR) techniques that registered corresponding anatomical voxels between images for tracking and accumulating dose throughout treatment. DIR also enabled voxel-level dose-response correlation when CT image density …
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Comparison of Tumor Shrinkage and Cumulative Dose Distribution For Lung Cancers
… contours were propagated to T50 of weekly 4DCT images using deformable image registration and their absolute volumes were measured. Statistical analysis was performed to compare the distribution of tumor shrinkage between the two population groups. In order to investigate the difference between …
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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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