Evaluation Of An End-To-End Radiotherapy Treatment Planning Pipeline For Prostate Cancer, 2024 The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences
Evaluation Of An End-To-End Radiotherapy Treatment Planning Pipeline For Prostate Cancer, Mohammad Daniel El Basha, Court Laurence, Carlos Eduardo Cardenas, Julianne Pollard-Larkin, Steven Frank, David T. Fuentes, Falk Poenisch, Zhiqian H. Yu
Dissertations & Theses (Open Access)
Radiation treatment planning is a crucial and time-intensive process in radiation therapy. This planning involves carefully designing a treatment regimen tailored to a patient’s specific condition, including the type, location, and size of the tumor with reference to surrounding healthy tissues. For prostate cancer, this tumor may be either local, locally advanced with extracapsular involvement, or extend into the pelvic lymph node chain. Automating essential parts of this process would allow for the rapid development of effective treatment plans and better plan optimization to enhance tumor control for better outcomes.
The first objective of this work, to automate the treatment …
Chest Computed Tomography And Magnetic Resonance Imaging Texture Measurements Of Chronic Obstructive Pulmonary Disease, 2024 The University of Western Ontario
Chest Computed Tomography And Magnetic Resonance Imaging Texture Measurements Of Chronic Obstructive Pulmonary Disease, Maksym Sharma
Electronic Thesis and Dissertation Repository
Pulmonary imaging using computed tomography (CT) and magnetic resonance imaging (MRI) provide a method to measure airway and parenchymal pathologic information that cannot be provided using spirometry. Currently, it remains difficult to predict which chronic obstructive pulmonary disease (COPD) patients will worsen using spirometry, which although safe and inexpensive, does not provide small airway information where COPD is believed to initiate. Quantitative CT and MRI measurements provide regional structure and function information but are not included in mortality risk assessments, prognosis, or COPD staging. Therefore, my overarching hypothesis is that CT and MRI ventilation texture measurements combined with machine learning …
Structure And Function Of Long-Covid Evaluated Using Pulmonary Imaging, 2024 The University of Westen Ontario
Structure And Function Of Long-Covid Evaluated Using Pulmonary Imaging, Harkiran Kaur Kooner
Electronic Thesis and Dissertation Repository
The COVID-19 pandemic has resulted in millions of global respiratory infections, ranging in severity from asymptomatic to fatal. One of the many consequences of the pandemic is the emergence of long-COVID, which is an umbrella term used to describe the long-term sequelae and poor quality-of-life following recovery from acute COVID-19 infection. However, the pathophysiology and mechanisms responsible for the heterogenous manifestation of long-COVID remain poorly understood. Hyperpolarized 129Xe magnetic resonance imaging (MRI) provides a non-invasive and radiation-free method to regionally visualize and quantify inhaled gas distribution and ventilation in vivo. A strong foundation for the use of pulmonary …
The Impact Of Simulated Image Acquisition Time Reduction On Image Quality And Parameters Of Myocardial Perfusion Imaging Using A Dedicated Cardiac Camera, 2024 Western University
The Impact Of Simulated Image Acquisition Time Reduction On Image Quality And Parameters Of Myocardial Perfusion Imaging Using A Dedicated Cardiac Camera, Alireza Khatami
Electronic Thesis and Dissertation Repository
Heart disease is the second leading cause of death in Canada, highlighting the crucial role of early diagnosis in disease management. Myocardial perfusion imaging (MPI), is widely employed for this purpose, involves injecting a radiopharmaceutical into the body, imaging its distribution with a gamma camera, and revealing cardiac blood flow patterns. A significant challenge in MPI is the lengthy 8 to 10 minutes required for stress and rest imaging, potentially causing patient discomfort and compromising image quality due to movement. In a clinical study with 26 patients, post-processed data manipulation simulated a reduction in MPI imaging time. The findings indicated …
Development Of Ph-Weighted Magnetic Resonance Imaging In The Spinal Cord: Application In Degenerative Cervical Myelopathy, 2024 The University of Western Ontario
Development Of Ph-Weighted Magnetic Resonance Imaging In The Spinal Cord: Application In Degenerative Cervical Myelopathy, Alicia E. Cronin
Electronic Thesis and Dissertation Repository
Degenerative cervical myelopathy (DCM) is a degenerative disease of the spinal cord that can lead to neurological dysfunction. It has been hypothesized that ischemia and hypoxia in the spinal cord at the site of compression could impact functional recovery after decompression surgery. Unfortunately, direct in-vivo quantification of hypoxia and ischemia in the spine has been limited in humans. Magnetic resonance imaging (MRI) can be utilized to measure hypoxia indirectly in soft tissue. Specifically, chemical exchange saturation transfer (CEST) is an MRI contrast that can be derived from the transfer of magnetization from selectively excited endogenous protons to bulk water protons. …
Editorial; Biophysics Approaches To Investigate Multi-Organ Alcohol-Induced Damage, 2023 LSU Health Sciences Center - New Orleans
Editorial; Biophysics Approaches To Investigate Multi-Organ Alcohol-Induced Damage, Janos Paloczi, Youngchan Kim
School of Graduate Studies Faculty Publications
No abstract provided.
Assessing The Sensitivity Of Cerebral Blood Flow And Oxygenation To High Intracranial Pressure With Near-Infrared Light, 2023 Western University
Assessing The Sensitivity Of Cerebral Blood Flow And Oxygenation To High Intracranial Pressure With Near-Infrared Light, Sule Karagulleoglu Kunduraci
Electronic Thesis and Dissertation Repository
Premature birth is associated with increased susceptibility to cerebral injuries because of the compounded effects of underdeveloped cerebral vascular and unstable hemodynamics. Notably, premature infants are highly vulnerable to intraventricular hemorrhage, which often leads to hydrocephalus and subsequently to high intracranial pressure (ICP). Current monitoring methods such as ultrasonography can only detect injuries that have already occurred, highlighting the need for prognostic tools. We hypothesize that concomitant measures of cerebral blood flow (CBF), blood oxygenation, and oxygen metabolism will be sensitive to high ICP. To test this hypothesis, experiments were conducted in a piglet model of high ICP using a …
The Development Of Artificial Intelligence-Based Tools For Expert Peer Review Of Radiotherapy Treatment Plans, 2023 The Texas Medical Center Library
The Development Of Artificial Intelligence-Based Tools For Expert Peer Review Of Radiotherapy Treatment Plans, Mary Gronberg
Dissertations & Theses (Open Access)
Creating a patient-specific radiation treatment plan is a time-consuming and operator-dependent manual process. The treatment planner adjusts the planning parameters in a trial-and-error fashion in an effort to balance the competing clinical objectives of tumor coverage and normal tissue sparing. Often, a plan is selected because it meets basic organ at risk dose thresholds for severe toxicity; however, it is evident that a plan with a decreased risk of normal tissue complication probability could be achieved. This discrepancy between “acceptable” and “best possible” plan is magnified if either the physician or treatment planner lacks focal expertise in the disease site. …
Eosinophilic Asthma Response To Therapy: 129xe Magnetic Resonance Imaging And Computed Tomography, 2023 The University of Western Ontario
Eosinophilic Asthma Response To Therapy: 129xe Magnetic Resonance Imaging And Computed Tomography, Marrissa Joan Mcintosh
Electronic Thesis and Dissertation Repository
Novel biologic therapies, such as anti-interleukin-5 receptor α (anti-IL-5Rα) or benralizumab, have been developed to treat patients with severe eosinophilic asthma who experience frequent exacerbations, poor quality of life and increased risk of mortality. Whether this therapy results in disease modifying activity, specifically in the asthmatic airways and pulmonary vasculature, is still poorly understood. Pulmonary structure and function may be evaluated using computed tomography (CT) and hyperpolarized noble gas magnetic resonance imaging (MRI), respectively. Computed tomography has previously been utilized to measure airway dimensions, mucus occlusions and pulmonary blood volumes. In contrast, hyperpolarized gas MRI allows for the in vivo …
Water-Fat Magnetic Resonance Imaging For The Assessment Of Human Fetal Adipose Tissue, 2023 Western University
Water-Fat Magnetic Resonance Imaging For The Assessment Of Human Fetal Adipose Tissue, Stephanie A. Giza
Electronic Thesis and Dissertation Repository
Adipose tissue is crucial for providing heat and energy to infants, especially at transitions such as birth and therefore must begin developing in utero. This development may be altered due to an adverse uterine environment, increasing the risk of developing later-life metabolic diseases such as obesity. An early assessment of fetal adipose tissue development through lipid accumulation could be key to understanding metabolic programming and minimizing this risk.
Water-fat magnetic resonance imaging (MRI) can non-invasively measure the lipid concentration of tissues and can therefore monitor the development of adipose tissue via tissue lipid concentration. This work demonstrated the feasibility …
Predicting Brain Metastasis Response To Stereotactic Radiosurgery Using Magnetic Resonance Imaging Radiomics And Machine Learning, 2023 Western University
Predicting Brain Metastasis Response To Stereotactic Radiosurgery Using Magnetic Resonance Imaging Radiomics And Machine Learning, David A. Devries
Electronic Thesis and Dissertation Repository
Brain metastases (BMs) represent advanced cancer, and so BM patients must be treated quickly and effectively while minimizing treatment toxicities. Stereotactic radiosurgery (SRS) uses conformal, ablative radiation doses to treat BMs, but with failure rates up to 30%. A predictive model of BM progression post-SRS would therefore aid in BM treatment selection and SRS planning. Previous studies have used pre-treatment T1-weighted contrast-enhanced magnetic resonance imaging (T1w-CE MRI) to predict SRS outcomes, through quantitative radiomic analysis with machine learning (ML) and qualitative appearance analysis. Comparison of these methods is not well understood, and ML methods have not been studied for sensitivity …
A Computational Model Of Multiple Interconnected Capillary Modules In Skeletal Muscle, 2023 Western University
A Computational Model Of Multiple Interconnected Capillary Modules In Skeletal Muscle, Raashi Vijay
Electronic Thesis and Dissertation Repository
Background: Skeletal muscle (SM), with its precise O2 supply-demand matching, is ideal for studying microvascular (MV) function, which is crucial in cardiovascular physiology and disease. Our goal is to gain understanding of SM microcirculation using recent capillary network module (CM) data from rat in a computational model.
Methods: We construct a 4-CM network, with single-vessel equivalents for each CM, three arterioles, and two venules. A two-phase (plasma/RBCs) steady-state model is used to calculate blood flow. An iterative boundary pressure finding method is developed to match flow in CMs.
Results: We validate our flow and pressure models …
Assessment Of A Novel High-Density, Full-Head Coverage, Time-Resolved Near-Infrared Spectroscopy (Nirs) Device For Intraoperative Neuromonitoring, 2023 Western University
Assessment Of A Novel High-Density, Full-Head Coverage, Time-Resolved Near-Infrared Spectroscopy (Nirs) Device For Intraoperative Neuromonitoring, Farah Kamar
Electronic Thesis and Dissertation Repository
Neuromonitoring during surgery is used to detect early indications of cerebral injury before permanent damage occurs. A commonly used technology is cerebral oximetry; however, current systems only monitor one brain region and have limited depth sensitivity. A newly developed NIRS system, Kernel Flow, offers the possibility to address both limitations by providing full-head coverage and time-resolved detection to enhance sensitivity to the brain. This work aimed to assess Kernel Flow’s sensitivity to regional cerebral oxygenation changes. Two experiments were conducted. In the first, decreases in cerebral oxygenation caused by transient carotid compression were measured in healthy volunteers. The second was …
In Utero Magnetic Resonance Relaxometry For Fetal Tissue Development, 2023 Western University
In Utero Magnetic Resonance Relaxometry For Fetal Tissue Development, Simran Sethi
Electronic Thesis and Dissertation Repository
Fetal life is a significant period of human development because organ systems that sustain life outside the uterus begin to develop during this time. A necessary process that begins during fetal life is myelination, which is the process by which myelin, a lipid-rich substance, is wrapped around neurons in the brain to increase the speed of action potential transmission. Since myelination is critical for the normal function of the central nervous system, fetal myelin assessment is important for understanding neurodevelopment and neurodegeneration, such as intrauterine growth restriction (IUGR).
Magnetic resonance imaging (MRI) is an excellent tool for visualizing fetal anatomy …
Development And Validation Of Mechatronic Systems For Image-Guided Needle Interventions And Point-Of-Care Breast Cancer Screening With Ultrasound (2d And 3d) And Positron Emission Mammography, 2023 Western University
Development And Validation Of Mechatronic Systems For Image-Guided Needle Interventions And Point-Of-Care Breast Cancer Screening With Ultrasound (2d And 3d) And Positron Emission Mammography, Claire Ks Park
Electronic Thesis and Dissertation Repository
The successful intervention of breast cancer relies on effective early detection and definitive diagnosis. While conventional screening mammography has substantially reduced breast cancer-related mortalities, substantial challenges persist in women with dense breasts. Additionally, complex interrelated risk factors and healthcare disparities contribute to breast cancer-related inequities, which restrict accessibility, impose cost constraints, and reduce inclusivity to high-quality healthcare. These limitations predominantly stem from the inadequate sensitivity and clinical utility of currently available approaches in increased-risk populations, including those with dense breasts, underserved and vulnerable populations.
This PhD dissertation aims to describe the development and validation of alternative, cost-effective, robust, and high-resolution …
Advancing Non-Invasive Imaging Techniques For Tracking Cellular Therapeutics In Vivo, 2023 University of Western Ontario
Advancing Non-Invasive Imaging Techniques For Tracking Cellular Therapeutics In Vivo, Olivia C. Sehl
Electronic Thesis and Dissertation Repository
Cell therapies, including mesenchymal stem cells (MSC) and regulatory T cells (Tregs) have shown potent and long-lasting therapeutic benefit in several disease applications. Unfortunately, the effectiveness of these therapies is variable and following administration, it is largely unknown where therapeutic cells traffic and how many persist over time. This thesis aims to advance and compare iron- and fluorine-19 (19F)-based magnetic resonance imaging (MRI) and magnetic particle imaging (MPI) for therapeutic cell tracking.
First, we developed a trimodal imaging approach to study MSC fate in vivo. In a mouse model, iron-labeled MSC were detected by MRI and MPI, …
Development Of Magnetic Particle Imaging For Quantitative Immune Cell Tracking, 2023 Western University
Development Of Magnetic Particle Imaging For Quantitative Immune Cell Tracking, Julia J. Gevaert
Electronic Thesis and Dissertation Repository
The Foster lab has been developing cellular MRI tools for well over a decade using superparamagnetic iron oxide (SPIO)-based contrast agents for numerous applications cell tracking applications. SPIO are used to label cells which are indirectly detected as regions of signal loss. The main challenge with this technique is quantification of cell number, which is important for applications such as dendritic cell (DC)-based immunotherapies where cell number is used as a predictor of immunotherapeutic response.
Magnetic particle imaging (MPI) is a novel pre-clinical modality that shows promise for cell tracking. MPI directly detects the nonlinear magnetization response of superparamagnetic iron …
Spatiotemporal Optimization Of Intratumoural Electric Field Modulation For Cancer Therapy, 2023 Western University
Spatiotemporal Optimization Of Intratumoural Electric Field Modulation For Cancer Therapy, Erin Iredale
Electronic Thesis and Dissertation Repository
The use of anti-cancer non-ablative electric fields is an expanding area of research that includes clinically available external devices for the treatment of glioblastoma (GBM), and a pre-clinical internal system called Intratumoural Modulation Therapy (IMT). IMT uses multiple electrodes implanted within the tumour to apply low intensity electric fields (~1 V/cm) focused on the target region, anywhere in the brain, with no externally visible devices. In this thesis, multi-electrode spatiotemporally dynamic IMT is investigated through computer simulation, numerical optimization, brain phantom and in vitro validation methods. These planning and validation strategies are hypothesized to improve tumour coverage with the necessary …
Sexual Dimorphism Of Glomerular Capillary Morphology In Rats, 2023 East Tennessee State University
Sexual Dimorphism Of Glomerular Capillary Morphology In Rats, Zackarias Coker
Undergraduate Honors Theses
Chronic kidney disease (CKD) progresses faster in males than females; however, the underlying mechanisms remain poorly understood. Sex differences in glomerular capillary morphology has been hypothesized to contribute, in part, to the increased susceptibility to hypertension-induced renal injury and CKD progression in males, but this has not been investigated. The goal of the present study was to assess glomerular capillary morphology in male vs. female rats with intact kidneys and after uninephrectomy (UNX). We hypothesized that glomerular capillary radii (RCAP) and length (LCAP) would be greater in male rats.
Male (n=4) and female (n=4) with intact …
Automating The Radiation Therapy Treatment Planning Process For Pediatric Patients With Medulloblastoma, 2023 The Texas Medical Center Library
Automating The Radiation Therapy Treatment Planning Process For Pediatric Patients With Medulloblastoma, Soleil Hernandez
Dissertations & Theses (Open Access)
Over the past 50 years, pediatric cancer 5-year survival rates increased from 20% to 80% in high-income countries, however, these trends have not been mirrored in low-and-middle-income countries (LMICs). This is due in part to delayed diagnosis, higher rates of advanced disease at presentation and a growing lack of access to high quality medical personnel and technology necessary to deliver complex treatments.
The long-term goal of this study was to alleviate demanding workflows and increase global access to high-quality pediatric radiation therapy by harnessing the power of artificial intelligence to automate the radiation therapy treatment planning process for pediatric patients …