Bioimaging and Biomedical Optics Commons^™

Study Of Immobilizing Cadmium Selenide Quantum Dots In Selected Polymers For Application In Peroxyoxalate Chemiluminescence Flow Injection Analysis, Christopher S. Moore

Electronic Theses and Dissertations

Two batches of CdSe QDs with different sizes were synthesized for immobilizing in polyisoprene (PI), polymethylmethacrylate (PMMA), and low-density polyethylene (LDPE). The combinations of QDs and polymer substrates were evaluated for their analytical fit-for-use in applicable immunoassays. Hydrogen peroxide standards were injected into the flow injection analyzer (FIA) constructed to simulate enzyme-generated hydrogen peroxide reacting with bis-(2,4,6-trichlorophenyl) oxalate.

Linear correlations between hydrogen peroxide and chemilumenscent intensities yielded regression values greater than 0.9750 for hydrogen peroxide concentrations between 1.0 x 10^-4 M and 1.0 x 10^-1 M. The developed technique’s LOD was approximately 10 ppm. Variability of the prepared …

A Gamos Plug-In For Geant4 Based Monte Carlo Simulation Of Radiation-Induced Light Transport In Biological Media, Adam K. Glaser, Stephen C. Kanick, Rongxiao Zhang, Pedro Arce, Brian W. Pogue

Dartmouth Scholarship

We describe a tissue optics plug-in that interfaces with the GEANT4/GAMOS Monte Carlo (MC) architecture, providing a means of simulating radiation-induced light transport in biological media for the first time. Specifically, we focus on the simulation of light transport due to the Čerenkov effect (light emission from charged particle's traveling faster than the local speed of light in a given medium), a phenomenon which requires accurate modeling of both the high energy particle and subsequent optical photon transport, a dynamic coupled process that is not well-described by any current MC framework. The results of validation simulations show excellent agreement with …

Toward Characterization Of Diseased Vascular Structures Using Noncontact Photoacoustic And Laser-Ultrasound Imaging: A Phantom Study, Jami Lynne Johnson

Boise State University Theses and Dissertations

Visualizing and characterizing atherosclerotic plaques is important in determining the vulnerability of a plaque to rupture. To evaluate rupture risk, several compositional factors should be evaluated, including inflammation, the presence and size of lipid pools, thickness of the fibrous cap, and calcification. Currently, a need exists for an imaging modality that can detect each of these factors in a safe, noninvasive manner with high resolution and contrast at clinically relevant depths. Photoacoustic imaging is a growing field that has the potential to improve plaque diagnosis. Spectroscopic methods have shown promise toward detection of constituents of plaque with unique optical absorption …

Delayed Thrombus Resolution And Fibroproliferative Vascular Wound Healing From Deficiency Of Type Iii Collagen: A Paradoxical Mechanism For Tissue Fragility, Amy J. Reid

Dissertations and Theses (Open Access)

Vascular Ehlers-Danlos syndrome is a heritable disease of connective tissue caused by mutations in COL3A1, conferring a tissue deficiency of type III collagen. Cutaneous wounds heal poorly in these patients, and they are susceptible to spontaneous and catastrophic rupture of expansible hollow organs like the gut, uterus, and medium-sized to large arteries, which leads to premature death. Although the predisposition for organ rupture is often attributed to inherent tissue fragility, investigation of arteries from a haploinsufficient Col3a1 mouse model (Col3a1^+/-) demonstrates that mutant arteries withstand even supraphysiologic pressures comparably to wild-type vessels. We hypothesize that injury …

A Microfluidic Pretreatment Isoelectric Focusing Dc-Field Assisted H-Filter For The Separation Of Charged Particles, Cameron Sean Carroll

Biomedical Engineering

Microfluidic devices are small portable diagnostic chips that allow for analysis of a biologic sample at relatively low cost. This makes them ideal for settings where a hospital is unavailable. The microfluidic pretreatment isoelectric focusing DC-field assisted H-filter is a device that allows for the separation of differently charged particles in a biologic sample. It does this by employing the concepts of diffusion, electrophoresis, and isoelectric focusing. This is perfect for isolation of a desired analyte or separation of waste from a sample in order to achieve better diagnostic results. The device was first modeled mathematically and visually using Comsol. …

Picture Of A Chelate In Exchange: The Crystal Structure Of Nahodotma, A 'Semi'-Hydrated Chelate, Katherine M. Payne, Edward J. Valente, Silvio Aime, Mauro Botta, Mark Woods

Chemistry Faculty Publications and Presentations

Crystallography generally only provides static structural information. This can render it an ineffective technique for probing dynamic solution state processes. A crystal of HoDOTMA affords unique structures that effectively represent that of a lanthanide tetra-acetate chelate mid-way through the water exchange process.

Automated Point-Of-Care Image Processing Methodology For The Diagnosis Of Malaria, Michael B. Jorgensen

Master's Theses

Malaria has profoundly influenced human history for over four thousand years and despite numerous attempts at eradication, the prevention, diagnosis, and treatment of malaria have been largely ineffective. More than five hundred million people are affected by malaria every year resulting in over one million deaths. Drug resistance development by the parasite has diminished the effectiveness of numerous treatment options due, in part, to overtreatment of negative patients based on insufficient clinical algorithms and diagnostic methods. The goal of this research was to develop an image analysis algorithm to diagnose malaria with a high degree of sensitivity and specificity in …

Scanning In Situ Spectroscopy Pplatform For Imaging Surgical Breast Tissue Specimens, Venkataramanan Krishnaswamy, Ashley M. Laughney, Wendy A. Wells, Keith D. Paulsen, Brian W. Pogue

Dartmouth Scholarship

A non-contact localized spectroscopic imaging platform has been developed and optimized to scan 1 x 1 cm² square regions of surgically resected breast tissue specimens with ~150-micron resolution. A color corrected, image-space telecentric scanning design maintained a consistent sampling geometry and uniform spot size across the entire imaging field. Theoretical modeling in ZEMAX allowed estimation of the spot size, which is equal at both the center and extreme positions of the field with ~5% variation across the designed waveband, indicating excellent color correction. The spot sizes at the center and an extreme field position were also measured experimentally using the …

The Role Of Tissue Sound Speed As A Surrogate Marker Of Breast Density, Mark Sak

Wayne State University Dissertations

Breast density is one of the strongest predictors of breast cancer risk as women with the densest breasts have a three- to five-fold increase in risk compared to women with the least dense breasts. Breast density is currently measured by using mammography, the current gold standard for breast imaging. There are many shortcomings to using mammography to measure breast density, including the use of ionizing radiation. Ultrasound tomography (UST) does not use ionizing radiation and can create tomographic breast sound speed images. These sound speed images are useful because breast density is proportional to sound speed. The purpose of this …

Automatic Detection Of Polypoid Skin Lesions: The Squash Sign, Saurabh G. Karnik

Masters Theses

“Earlier detection of malignant melanoma can save lives. Automatic in-vivo methods of melanoma detection including smart-phone applications are now available, but specificity is low, i.e. too many benign lesions are detected as possible melanomas. Polypoids, elevated and rounded lesions are one class of benign lesions. These raised lesions with piecewise circular borders, predominantly intradermal nevi and cutaneous polyps (IDNs), are always benign. Variegated coloring present in polypoid lesions can lead physicians to perform an unneeded biopsy. Contact dermatoscope plates with gel squash these lesions, leaving a “squash sign” marker of benignancy which can be automatically detected. We present a method …

Significance And Analysis Of Milia-Like Cysts In Dermoscopy Skin Lesion Images, Sneha K. Mahajan

Masters Theses

“Milia-like cysts (MLCs) are dermoscopic structures frequently observed in seborrheic keratoses(SKs), which are the most common type of skin lesions. Diverse appearances of these skin lesions make them difficult to differentiate from melanoma, a deadly type of skin cancer. Classified by size into two main groups, starry MLCs and cloudy MLCs, the presence of these structures in a skin lesion has been known to help differentiate benign lesions from melanoma. Though the presence of cloudy MLCs is not exclusively associated with SKs, they can be a useful tool to differentiate SKs from melanoma. This research study determines the statistical occurrence …

Compressed Sensing And Joint Acquisition Techniques In Mri, Rouhollah Hamtaei

Wayne State University Theses

The relatively long scan times in Magnetic Resonance Imaging (MRI) limits some clinical applications and the ability to collect more information in a reasonable period of time. Practically, 3D imaging requires longer acquisitions which can lead to a reduction in image quality due to motion artifacts, patient discomfort, increased costs to the healthcare system and loss of profit to the imaging center. The emphasis in reducing scan time has been to a large degree through using limited k-space data acquisition and special reconstruction techniques. Among these approaches are data extrapolation methods such as "constrained reconstruction" techniques, data interpolation methods such …

Noninvasive Near-Infrared Diffuse Optical Monitoring Of Cerebral Hemodynamics And Autoregulation, Ran Cheng

Theses and Dissertations--Biomedical Engineering

Many cerebral diseases are associated with abnormal cerebral hemodynamics and impaired cerebral autoregulation (CA). CA is a mechanism to maintain cerebral blood flow (CBF) stable when mean arterial pressure (MAP) fluctuates. Evaluating these abnormalities requires direct measurements of cerebral hemodynamics and MAP. Several near-infrared diffuse optical instruments have been developed in our laboratory for hemodynamic measurements including near-infrared spectroscopy (NIRS), diffuse correlation spectroscopy (DCS), hybrid NIRS/DCS, and dual-wavelength DCS flow-oximeter. We utilized these noninvasive technologies to quantify CBF and cerebral oxygenation in different populations under different physiological conditions/manipulations. A commercial finger plethysmograph was used to continuously monitor MAP. For investigating …

Recovering Local Neural Tract Directions And Reconstructing Neural Pathways In High Angular Resolution Diffusion Mri, Ning Cao

Theses and Dissertations--Computer Science

Magnetic resonance imaging (MRI) is an imaging technique to visualize internal structures of the body. Diffusion MRI is an MRI modality that measures overall diffusion effect of molecules in vivo and non-invasively. Diffusion tensor imaging (DTI) is an extended technique of diffusion MRI. The major application of DTI is to measure the location, orientation and anisotropy of fiber tracts in white matter. It enables non-invasive investigation of major neural pathways of human brain, namely tractography. As spatial resolution of MRI is limited, it is possible that there are multiple fiber bundles within the same voxel. However, diffusion tensor model is …

Visual Exploration And Information Analytics Of High-Dimensional Medical Images, Darshan Pai

Wayne State University Dissertations

Data visualization has transformed how we analyze increasingly large and complex data sets. Advanced visual tools logically represent data in a way that communicates the most important information inherent within it and culminate the analysis with an insightful conclusion. Automated analysis disciplines - such as data mining, machine learning, and statistics - have traditionally been the most dominant fields for data analysis. It has been complemented with a near-ubiquitous adoption of specialized hardware and software environments that handle the storage, retrieval, and pre- and postprocessing of digital data. The addition of interactive visualization tools allows an active human participant in …

Morphometric, Biochemical, And Raman Spctral Analyses Of Muscle Damage In Patients With Peripheral Arterial Disease: Provising Objective Criteria For Diagnosis And Treatment Monitoring, Kim Cluff

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Peripheral arterial disease (PAD), which affects approximately 10 million Americans, is characterized by atherosclerosis of the non-coronary arteries. PAD produces a progressive accumulation of ischemic injury to the limbs that is reflected in a gradual worsening in the myofiber morphology and oxidative damage in the gastrocnemius muscle. In this study, we evaluated the hypothesis that quantitative morphological and biochemical parameters of gastrocnemius myofibers change in a consistent manner during the progression of PAD, provide an objective grading of muscle degeneration in the ischemic limb, and correlate to clinical stage of PAD. Myofiber morphometrics were determined precisely with mathematical equations that …

Implementation Of Magnetic Resonance Elastography For The Investigation Of Traumatic Brain Injuries, Thomas Boulet

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Magnetic resonance elastography (MRE) is a potentially transformative imaging modality allowing local and non-invasive measurement of biological tissue mechanical properties. It uses a specific phase contrast MR pulse sequence to measure induced vibratory motion in soft material, from which material properties can be estimated. Compared to other imaging techniques, MRE is able to detect tissue pathology at early stages by quantifying the changes in tissue stiffness associated with diseases. In an effort to develop the technique and improve its capabilities, two inversion algorithms were written to evaluate viscoelastic properties from the measured displacements fields. The first one was based on …

Quantitative, Spectrally-Resolved Intraoperative Fluorescence Imaging, Pablo A. Valdés, Frederic Leblond, Valerie L. Jacobs, Brian C. Wilson, Keith D. Paulsen, David W. Roberts

Dartmouth Scholarship

Intraoperative visual fluorescence imaging (vFI) has emerged as a promising aid to surgical guidance, but does not fully exploit the potential of the fluorescent agents that are currently available. Here, we introduce a quantitative fluorescence imaging (qFI) approach that converts spectrally-resolved data into images of absolute fluorophore concentration pixel-by-pixel across the surgical field of view (FOV). The resulting estimates are linear, accurate, and precise relative to true values, and spectral decomposition of multiple fluorophores is also achieved. Experiments with protoporphyrin IX in a glioma rodent model demonstrate in vivo quantitative and spectrally-resolved fluorescence imaging of infiltrating tumor margins for the …

A Digital X-Ray Tomosynthesis Coupled Near Infrared Spectral Tomography System For Dual-Modality Breast Imaging, Venkataramanan Krishnaswamy, Kelly E. Michaelsen, Brian W. Pogue, Steven P. Poplack, Ian Shaw, Ken Defrietas, Ken Brooks, Keith D. Paulsen

Dartmouth Scholarship

A Near Infrared Spectral Tomography (NIRST) system has been developed and integrated into a commercial Digital Breast Tomosynthesis (DBT) scanner to allow structural and functional imaging of breast in vivo. The NIRST instrument uses an 8-wavelength continuous wave (CW) laser-based scanning source assembly and a 75-element silicon photodiode solid-state detector panel to produce dense spectral and spatial projection data from which spectrally constrained 3D tomographic images of tissue chromophores are produced. Integration of the optical imaging system into the DBT scanner allows direct co-registration of the optical and DBT images, while also facilitating the synergistic use of x-ray contrast as …

Two-Dimensional Blood Flow Velocity Estimation Using Ultrasound Speckle Pattern Dependence On Scan Direction And Velocity, Tiantian Xu

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Cardiovascular disease is the leading cause death in the United States. Although emergency surgery and medicine can be used for cardiovascular disease treatment, the survivors will suffer for it afterwards. Ultrasound blood flow measurement provides a noninvasive way for cardiovascular diseases diagnosis. In this dissertation, three algorithms for blood flow velocity measurements were investigated and optimized. Feature tracking has been previously proposed for vector velocity measurement. In Chapter 3, the optimal amplitude and time thresholds for feature extraction were investigated to minimize flow estimate variance while providing sufficient spatial and temporal coverage of flow area. A new method of lateral …