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.
Results
Showing 1 to 20 of 33 for “"respiratory motion"”.
-
PREDICTION OF RESPIRATORY MOTION
… during radiation treatment. The prediction of respiratory motion has become an important research area because respiratory motion severely affects precise radiation dose delivery. This study describes recent radiotherapy technologies including tools for measuring target position during …
-
Approaches for respiratory motion compensation in positron emission tomography imaging
Respiratory patient motion often causes image blur and inaccurate quantitation results in positron emission tomography (PET) imaging. Traditional gated acquisition approach corrects motion artifacts by generating a snapshot sequence. Each snapshot, however, is of poor image quality due to …
-
Assessment of New Innovations In Pet/Ct For Respiratory Motion Correction
… However, due to the long acquisition times, respiratory motion blur is unavoidable in PET images especially in the lower lung and upper abdomen. This leads to reductions in measured radiotracer concentration and lesion detectability all of which can potentially result in incorrect management …
-
IMAGE-BASED RESPIRATORY MOTION EXTRACTION AND RESPIRATION-CORRELATED CONE BEAM CT (4D-CBCT) RECONSTRUCTION
Accounting for respiration motion during imaging helps improve targeting precision in radiation therapy. Respiratory motion can be a major source of error in determining the position of thoracic and upper abdominal tumor targets during radiotherapy. Thus, extracting respiratory motion is a key task …
-
Investigation of Respiratory Motion Management Techniques For Proton and Photon Radiotherapy of Lung Cancer
… radiation such as high-energy photons. However, respiratory motion can significantly impact the delivered proton and photon dose distributions during lung cancer radiotherapy. The goals of this dissertation research were to evaluate the impact of respiratory motion and to estimate the benefit of …
-
A control system approach to subject specific prospective respiratory motion correction in cardiac MRI
Respiratory motion of the heart is a problem for high-resolution cardiac MRI. Diaphragmatic navigator gating with a 5mm acceptance window is most commonly used to address this but has an inherently low respiratory efficiency that is further compromised by respiratory drift. A novel method is …
-
Four-Dimensional Imaging of Respiratory Motion in the Radiotherapy Treatment Room Using a Gantry Mounted Flat Panel Imaging Device
<p>Imaging respiratory induced tumor motion in the radiation therapy treatment room could eliminate the necessity for large motion encompassing margins that result in excessive irradiation of healthy tissues. Currently available image guidance technologies are ill-suited for this task. …
-
Segmented breast treatment planning incorporating 4D data acquisition
… traditional therapy, does not take into account respiratory motion. With breast cancer patients, this motion can expose healthy tissues, such as the lungs, to higher doses than expected. More significantly, respiratory motion can create hot spots in the breast tissue in excess of 15% of the …
-
4D Monte Carlo Based Patient Dose Reconstruction Incorporating Surface Motion Measurements
A framework was developed to assess the impact of respiratory motion on the dose delivered during radiotherapy using a previously validated 4D Monte Carlo-based dose reconstruction tool, 4Ddefdosxyznrc. As a surrogate for tumour motion, abdominal surface motion measurements were recorded during …
-
Evaluating and Improving 4D-CT Image Segmentation for Lung Cancer Radiotherapy
… delivery of radiation 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 …
-
Advanced Techniques for Cardiovascular Magnetic Resonance Imaging in Cases of Irregular Motion
… images with a high isotropic resolution is respiratory motion. Although a wide range of different methods to minimise res-piratory motion artefacts has been presented, irregular breathing can still lead to unacceptably long scan times and scan abortions. Respiratory motion in patients must …
-
Improvements In Robustness and Optimality of Intensity-Modulated Proton Therapy Plans For Lung Cancer Patients With 4-Dimensional Robust Optimization
… of uncertainties associated with breathing 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 …
-
Design and Optimization of Four-Dimensional Cone-Beam Computed to mography In Image-Guided Radiation Therapy
<p>The influence of respiratory motion on patient anatomy poses a challenge to accurate radiation therapy, especially in lung cancer treatment. Modern radiation therapy planning uses models of tumor respiratory motion to account for target motion in targeting. The tumor motion model can be verified …
-
The Effect of Heart Rate on Normal and Abnormal QRS Voltage
… the electrocardiographic paste, skin resistance, respiratory motion, age of the patient and many other factors can modify voltage. The effect of heart rate has been noted but not fully investigated particularly in regard to its influence upon the voltage criteria commonly used in the diagnosis of …
-
Investigation of Deformable Image Registration Based Lung Ventilation Mapping for Radiation Therapy Using a Hybrid Hyperpolarized Gas MRI Technique
… on a pair of anatomical lung images at different respiratory phases to obtain the displacement vector field (DVF) between both phases, and generate a lung ventilation map from the Jacobian Determinant of the DVF. This DIR-based method is advantageous in its high image resolutions and simpler …
-
A Frequency Loss Driven Framework for Respiration Monitoring Using Depth-Sensing Cameras
Respiratory monitoring is crucial for detecting physiological distress, yet traditional contact-based methods are often intrusive and impractical for long-term use. Non-contact approaches, particularly camera-based techniques, offer a promising alternative, but conventional RGB-based systems raise …
-
Verification of the <i>Ex Vivo</i> Thiel Embalmed Model for Liver Treatment with Magnetic Resonance-guided Focused Ultrasound (MRgFUS) before Clinical Practice
… is technically demanding due to the breathing motion and the presence of the ribcage around it, and non-invasive options are desirable. Magnetic Resonance-guided Focused Ultrasound (MRgFUS) is a promising treatment option due to its non-invasive nature and due to the ability to perform MR …
-
4D Study of Thoracic Cancer Radiation Treatment
Respiratory motion causes an added uncertainty in the radiation treatment of thoracic malignancies due to an increase in the normal tissue irradiated and an uncertainty in the radiation coverage of the tumor. This results in a potential increase in complications from treatment and may be …
-
Motion binning in cone-beam CT without a prior Model
… with CBCT has been to attempt to reconstruct the motion from these projections by collecting them into respiratory-phase or amplitude bins and using these to reconstruct bin-specific volumes. A variety of mechanisms are employed to identify and record respiratory motion so that it can be …
-
Soft Robotics Applied to the Development of a Diaphragm Assist System
Severe diaphragm dysfunction can lead to respiratory failure, requiring permanent mechanical ventilation. Permanent tethering to a mechanical ventilator via a patient’s mouth or tracheostomy can interfere with a patient’s autonomy by hindering activities like speech and swallowing. This thesis …
Page 1 of 2