Radiology Commons^™

Evaluation Of Bone And Muscle Quality In Laying Hens Using Quantitative, Radiographic, Computed Tomographic, Biomechanical, And Tissue Level Measures, Cerano Harrison

All Dissertations

Bone quality is an important measure of welfare in laying hens for researchers, veterinarians, and commercial producers who bear the responsibility of providing them with care. Breeding practices that have resulted in high egg productivity of laying hen strains have resulted in an increased susceptibility to developing osteoporosis. Osteoporosis, a decrease in mineralized bone, is accompanied by increased bone fragility that can lead to potentially painful bone fractures that can inhibit some aspects of the birds natural living, respiration and flight being two examples. Current methods of examining laying hen bone quality involve the implementation of diagnostic imaging and biomechanical …

Improving Dose-Response Correlations For Locally Advanced Nsclc Patients Treated With Imrt Or Pspt, Yulun He

Dissertations & Theses (Open Access)

The standard of care for locally advanced non-small cell lung cancer (NSCLC) is concurrent chemo-radiotherapy. Despite recent advancements in radiation delivery methods, the median survival time of NSCLC patients remains below 28 months. Higher tumor dose has been found to increase survival but also a higher rate of radiation pneumonitis (RP) that affects breathing capability. In fear of such toxicity, less-aggressive treatment plans are often clinically preferred, leading to metastasis and recurrence. Therefore, accurate RP prediction is crucial to ensure tumor coverage to improve treatment outcome. Current models have associated RP with increased dose but with limited accuracy as they …

Multiparametric Magnetic Resonance Imaging Artificial Intelligence Pipeline For Oropharyngeal Cancer Radiotherapy Treatment Guidance, Kareem Wahid

Dissertations & Theses (Open Access)

Oropharyngeal cancer (OPC) is a widespread disease and one of the few domestic cancers that is rising in incidence. Radiographic images are crucial for assessment of OPC and aid in radiotherapy (RT) treatment. However, RT planning with conventional imaging approaches requires operator-dependent tumor segmentation, which is the primary source of treatment error. Further, OPC expresses differential tumor/node mid-RT response (rapid response) rates, resulting in significant differences between planned and delivered RT dose. Finally, clinical outcomes for OPC patients can also be variable, which warrants the investigation of prognostic models. Multiparametric MRI (mpMRI) techniques that incorporate simultaneous anatomical and functional information …

Synthesis, Radiolabeling And Evaluation Of A Suite Of Tracers With 44Sc For Detecting Extracellular Dna, Zhiyao Li

McKelvey School of Engineering Theses & Dissertations

Neutrophil extracellular traps involve the rapid translocation of DNA to the outside of the cell under certain stimuli. This structure forms a fibrous network that is able to limit the spread of pathogens and to kill microorganisms. It has also been shown to be present in various pathological processes such as inflammation, autoimmune diseases, and cancer metastasis. Currently, the formation process of NETs in vivo is being extensively studied. However noninvasive detection and quantitation has yet to be achieved. A class of PET tracers are described here that consists of a DNA dye as the backbone that is labeled with …

Vertebral Endplate Structural Defects: Measurement, Prevalence And Associated Factors, Aliyu Lawan

Electronic Thesis and Dissertation Repository

Objective: To synthesize current knowledge on the association of endplate structural defects (EPSD) with back pain (BP), improve EPSD measurement, and investigate EPSD prevalence, distribution, and association with age and body mass index (BMI).

Methods: In study 1, a systematic review was conducted on five databases for studies reporting on the association between EPSD and BP. Studies 2 and 3 used CTs and mCTs of 19 embalmed cadavers to examine the diagnostic accuracy of common EPSD assessment methods, and to develop and validate a novel method. Study 4 used the novel method on 200 adult males’ MRI to estimate EPSD …

Sarcopenia In Head And Neck Cancer: A Prognostic Analysis, Nedeljko Jovanovic

Electronic Thesis and Dissertation Repository

Introduction: In head and neck cancer (HNC), loss of skeletal muscle mass (SMM), or sarcopenia, is a strong prognostic factor for outcomes. However, inconsistencies in its assessment limit our understanding of the relationship between sarcopenia and nutrition-related outcomes. This project evaluated the significance of sarcopenia as described in the literature and as demonstrated in a cohort of HNC patients.

Methods: A scoping review was first conducted followed by a retrospective cohort study with data collected from 194 oropharyngeal carcinoma patients treated with definitive radiation/chemoradiation. Sarcopenia was assessed from computed tomography (CT) imaging at the third cervical vertebra (C3) and the …

Improving The Reliability And Accessibility Of Ct Perfusion Imaging In Acute Ischemic Stroke, Kevin J. Chung

Electronic Thesis and Dissertation Repository

CT perfusion (CTP) imaging is a validated treatment decision support tool in acute ischemic stroke. Automated analysis of CTP cerebral blood flow (CBF) and Tmax maps produces estimates of ischemic core and penumbra volumes used to determine target mismatch profiles for treatment. However, availability and utilization of CTP is low due to diagnostic variability between CTP software and technical, logistical, and radiation dose considerations that may limit its routine adoption. The objective of this doctoral research was to improve the reliability and accessibility of CTP by (1) improving diagnostic agreement between CTP software, (2) enabling perfusion imaging with standard acute …

Alignment And Range Verification In Proton Therapy Using Proton Radiography And Proton Ct, Joseph Piet

Graduate Research Theses & Dissertations

Protons are used in radiation therapy to lower doses to healthy tissues by utilizing their Bragg peak. Protons can be used both in imaging and treatment. One of the uses of protons in imaging we tested is its use to align patients using a single beam's eye proton radiograph (pRad). By using a beam's eye pRad, and comparing the water equivalent thickness (WET) to proton digitally reconstructed radiographs (pDRRs), we show that we can measure the best alignment on six axes, three translational and three rotational. This is done by defining a cost function, chi squared, which quantifies the misalignment …

Verification Of Proton Range Predictions In Proton Treatment Planning Using X-Ray Ct Or Proton Ct Imaging, Nicholas S. Yee

Graduate Research Theses & Dissertations

The objective of this paper is to compare the range errors for two treatment plans; one using x-ray CT and the other using proton CT for calculating dose distributions in an animal tissue phantom. We shot 150 MeV proton beam through a meat phantom to a film stack to measure the exponential drop of dose at the Bragg peak until zero dose remained. Plotting the depth dose curves and performing gamma analyses are two ways to quantify the proton range errors when comparing them to depth dose curves from film measurements in the phantom. The depth dose curves give us …

Uncovering The Role Of Fat-Infiltrated Axillary Lymph Nodes In Obesity-Related Diseases With Statistical And Machine Learning Analyses, Qingyuan Song

Dartmouth College Ph.D Dissertations

The link between obesity and pathogenesis is a complex and multifaceted area of research that is yet to be fully understood. Ample evidence exists to demonstrate the direct relationship between excessive internal fat and various health conditions such as cancer, and metabolic and cardiovascular diseases. The infiltration of ectopic fat into axillary lymph nodes, observable on breast cancer screening images, has been shown to be correlated with body mass index (BMI) in women undergoing screening. This study aimed to explore the relationship between fat-infiltrated axillary lymph nodes (FIN) and obesity-related diseases, with the goal of evaluating the clinical value of …

Characterization Of A Solid-State Detector For Dosimetry In The Diagnostic Energy Range With Verification Via Monte Carlo Estimation Of Average Breast Dose In Mammography, Areej Aljabal

Theses and Dissertations

This dissertation aims to develop a simplified QA metric for estimating radiation dose in mammography. This metric, the Mid-Breast Dose (MDB) Index, maybe be proposed as an alternative dose index, consistent with average glandular dose (AGD), for routine QA. MBD was obtained using “Phantom mid-point Air Kerma (AK) measurement” for conventional mammography. The advantage of this method is that MBD can be measured directly without requiring multiple conversion factors. The accuracy of clinical measurements in computing the MBD was assessed by comparing it with the AGD estimated by the Dance formalism experimentally and Monte Carlo simulation.

MBD methodology relies on …