Biomedical Engineering and Bioengineering Commons^™

Diffuse Optical Measurements Of Head And Neck Tumor Hemodynamics For Early Prediction Of Chemo-Radiation Therapy Outcomes, Lixin Dong

Theses and Dissertations--Biomedical Engineering

Chemo-radiation therapy is a principal modality for the treatment of head and neck cancers, and its efficacy depends on the interaction of tumor oxygen with free radicals. In this study, we adopted a novel hybrid diffuse optical instrument combining a commercial frequency-domain tissue oximeter (Imagent) and a custom-made diffuse correlation spectroscopy (DCS) flowmeter, which allowed for simultaneous measurements of tumor blood flow and blood oxygenation. Using this hybrid instrument we continually measured tumor hemodynamic responses to chemo-radiation therapy over the treatment period of 7 weeks. We also explored monitoring dynamic tumor hemodynamic changes during radiation delivery. Blood flow data analysis …

Quantitative Spatial Frequency Fluorescence Imaging In The Sub-Diffusive Domain For Image-Guided Glioma Resection, Mira Sibai, Israel Veilleux, Jonathan T. Elliott, Frederic Leblond, Brian Wilson

Dartmouth Scholarship

Intraoperative 5- aminolevulinic acid induced-Protoporphyrin IX (PpIX) fluorescence guidance enables maximum safe resection of glioblastomas by providing surgeons with real-time tumor optical contrast. However, visual assessment of PpIX fluorescence is subjective and limited by the distorting effects of light attenuation and tissue autofluorescence. We have previously shown that non-invasive point measurements of absolute PpIX concentration identifies residual tumor that is otherwise non-detectable. Here, we extend this approach to wide-field quantitative fluorescence imaging by implementing spatial frequency domain imaging to recover tissue optical properties across the field-of-view in phantoms and ex vivo tissue.

Evaluation Of The Signature Molecular Descriptor With Blosum62 And An All-Atom Description For Use In Sequence Alignment Of Proteins, Lindsay M. Aichinger

Williams Honors College, Honors Research Projects

This Honors Project focused on a few aspects of this topic. The second is comparing the molecular signature kernels to three of the BLOSUM matrices (30, 62, and 90) to test the accuracy of the mathematical model. The kernel matrix was manipulated in order to improve the relationship by focusing on side groups and also by changing how the structure was represented in the matrix by increasing the initial height distance from the central atom (Height 1 and Height 2 included).

There were multiple design constraints for this project. The first was the comparison with the BLOSUM matrices (30, 62, …

Multi-Surface Simplex Spine Segmentation For Spine Surgery Simulation And Planning, Rabia Haq

Computational Modeling & Simulation Engineering Theses & Dissertations

This research proposes to develop a knowledge-based multi-surface simplex deformable model for segmentation of healthy as well as pathological lumbar spine data. It aims to provide a more accurate and robust segmentation scheme for identification of intervertebral disc pathologies to assist with spine surgery planning. A robust technique that combines multi-surface and shape statistics-aware variants of the deformable simplex model is presented. Statistical shape variation within the dataset has been captured by application of principal component analysis and incorporated during the segmentation process to refine results. In the case where shape statistics hinder detection of the pathological region, user-assistance is …

Femtosecond Laser Beam Propagation Through Corneal Tissue: Evaluation Of Therapeutic Laser-Stimulated Second And Third-Harmonic Generation, William R. Calhoun Iii

Theses and Dissertations

One of the most recent advancements in laser technology is the development of ultrashort pulsed femtosecond lasers (FSLs). FSLs are improving many fields due to their unique extreme precision, low energy and ablation characteristics. In the area of laser medicine, ophthalmic surgeries have seen very promising developments. Some of the most commonly performed surgical operations in the world, including laser-assisted in-situ keratomileusis (LASIK), lens replacement (cataract surgery), and keratoplasty (cornea transplant), now employ FSLs for their unique abilities that lead to improved clinical outcome and patient satisfaction.

The application of FSLs in medical therapeutics is a recent development, and although …

Computer Aided Detection Of Oral Lesions On Ct Images, Shaikat Mahmood Galib

Masters Theses

"Oral lesions are important findings on computed tomography images. They are difficult to detect on CT images because of low contrast, arbitrary orientation of objects, complicated topology and lack of clear lines indicating lesions. In this thesis, a fully automatic method to detect oral lesions from dental CT images is proposed to identify (1) Closed boundary lesions and (2) Bone deformation lesions. Two algorithms were developed to recognize these two types of lesions, which cover most of the lesion types that can be found on CT images. The results were validated using a dataset of 52 patients. Using non training …

Computer Aided Diagnosis Of Oral Cancer: Using Time-Step Ct Images, Jonathan T. Scott

Masters Theses

"In medical imaging it is a very common practice to use a technique known as Time-Step imaging in patients who might develop cancer. Time-Step imaging it a very powerful technique, however it can lead to unmanageable amounts of image data. Previously the only way to search all of this data was to manually look through all of the files. This had to be done by trained professionals who knew what to look for within the images and make a judgment about the patient based on the images. This paper discusses the development of an algorithm to have a computer search …

Adaptive Graph Construction For Isomap Manifold Learning, Loc Tran, Zezhong Zheng, Guoquing Zhou, Jiang Li, Karen O. Egiazarian (Ed.), Sos S. Agaian (Ed.), Atanas P. Gotchev (Ed.)

Electrical & Computer Engineering Faculty Publications

Isomap is a classical manifold learning approach that preserves geodesic distance of nonlinear data sets. One of the main drawbacks of this method is that it is susceptible to leaking, where a shortcut appears between normally separated portions of a manifold. We propose an adaptive graph construction approach that is based upon the sparsity property of the ℓ₁ norm. The ℓ₁ enhanced graph construction method replaces k-nearest neighbors in the classical approach. The proposed algorithm is first tested on the data sets from the UCI data base repository which showed that the proposed approach performs better than …

Monolithic Optofluidic Ring Resonator Lasers Created By Femtosecond Laser Nanofabrication, Hengky Chandrahalim, Qiushu Chen, Ali A. Said, Mark Dugan, Xudong Fan

Faculty Publications

We designed, fabricated, and characterized a monolithically integrated optofluidic ring resonator laser that is mechanically, thermally, and chemically robust. The entire device, including the ring resonator channel and sample delivery microfluidics, was created in a block of fused-silica glass using a 3-dimensional femtosecond laser writing process. The gain medium, composed of Rhodamine 6G (R6G) dissolved in quinoline, was flowed through the ring resonator. Lasing was achieved at a pump threshold of approximately 15 μJ/mm². Detailed analysis shows that the Q-factor of the optofluidic ring resonator is 3.3 × 10⁴, which is limited by both solvent …

Real-Time Temperature Imaging Using Ultrasonic Change In Backscattered Energy, Weiyuan Zhao

McKelvey School of Engineering Graduate Student Theses & Dissertations

Thermal therapy from low-temperature cryosurgery to high-temperature ablation of tumors and unwanted electrical pathways has gained increased attention. Temperature imaging (TI) from magnetic resonance studies is the de facto standard for volumetric estimation of temperature. Ultrasound has the advantages of being cheap, portable, non-invasive and non-ionizing. Our group showed in predictions for single scatterers, simulations of scatterer populations and measurements in 1D, 2D and 3D, that CBE changed monotonically with temperature with 1^oC accuracy. An obstacle to clinical application of CBE TI is estimation of temperature in real time, which is limited by time for motion compensation (MC). …

Applications Of Novel Mri Technologies In Tissue Engineering And Disease Diagnosis, Vahid Khalilzad-Sharghi

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

Magnetic resonance imaging (MRI) and magnetic resonance elastography (MRE) are increasingly under investigation to explore their potential role in establishing effective evaluation methods for the procedure of tissue regeneration carried out in vitro, in vivo, and in disease diagnosis. To this end, there is a continuous pursuit of novel tools both in vitro and in vivo. For instance, there is a great need for the development and evaluation of an MR-compatible incubation system that enables simultaneous monitoring and culturing of cell and tissue constructs using MRI techniques. Such an imagingcompatible incubation system eliminates exposing the culture to the risks of …

Pixel-Based Absorption Correction For Dual-Tracer Fluorescence Imaging Of Receptor Binding Potential, Stephen C. Kanick, Kenneth M. Tichauer, Jason Gunn, Kimberley S. Samkoe, Brian W. Pogue

Dartmouth Scholarship

Ratiometric approaches to quantifying molecular concentrations have been used for decades in microscopy, but have rarely been exploited in vivo until recently. One dual-tracer approach can utilize an untargeted reference tracer to account for non-specific uptake of a receptor-targeted tracer, and ultimately estimate receptor binding potential quantitatively. However, interpretation of the relative dynamic distribution kinetics is confounded by differences in local tissue absorption at the wavelengths used for each tracer. This study simulated the influence of absorption on fluorescence emission intensity and depth sensitivity at typical near-infrared fluorophore wavelength bands near 700 and 800 nm in mouse skin in order …

Data Completion Methods For Improved Developmental Stage Annotation Of Drosophila Embryos In Images, Chitsanu Janyalikit

Electrical & Computer Engineering Theses & Dissertations

Drosophila melanogaster is a dominant model organism for studying the function of animal genes in initial stages of embryogenesis. Usually, images containing Drosophila gene expression patterns are captured at different developmental stages to study the interconnection of animal genes. To achieve most biologically meaningful results, gene expression images from a similar stage should be compared. Currently, biologists manually classify embryos in images into different stages, which is time intensive and infeasible for current massively produced gene expression images. Therefore, there is a need to develop an automatic system for the annotation.

Gene expression information in embryo images usually appears as …

Apparatus And Method For Remote Assessment And Therapy Management In Medical Devices Via Interface Systems, Jeffrey Hargrove, Robert M. Ford, Thomas B. Johnson

Mechanical Engineering Patents

A remote medical assessment and therapy management apparatus comprising a center user interface, a center computer coupleable with the center user interface. The center computer displays information via the center user interface for use in developing a therapeutic prescription and receives therapeutic control inputs from a user. A remote device includes a medical diagnostic instrument for acquiring biophysical data from a patient, a medical therapeutic instrument that provides a therapy to the patient, and a remote computer that receives diagnostic signals from the diagnostic instrument and transmits therapeutic control signals to the therapeutic instrument. A network interface is connected between …

Anatomy-Based Transmission Factors For Technique Optimization In Portable Chest X-Ray, Chris L. Liptak, W. Paul Segars, Ashraf G. Morgan, Frank F. Dong, Xiang Li

Undergraduate Research Posters 2014

Currently, portable x-ray examinations do not employ automatic exposure control (AEC). To aid in the design of a size-specific technique chart, acrylic slabs of various thicknesses are often used to estimate x-ray transmission factors for patients of various body thicknesses. This approach, while simple, does not account for patient anatomy, tissue heterogeneity, and the attenuation properties of the human body. To better account for these factors, in this work, we determined x-ray transmission factors using computational patient models that are anatomically realistic. A Monte Carlo program was developed to model a portable x-ray system. Detailed modeling was done of the …

Sub-Diffusive Scattering Parameter Maps Recovered Using Wide-Field High-Frequency Structured Light Imaging, Stephen C. Kanick, David M. Mcclatchy, Venkataramanan Krishnaswamy, Jonathan T. Elliott, Keith D. Paulsen, Brian W. Pogue

Dartmouth Scholarship

This study investigates the hypothesis that structured light reflectance imaging with high spatial frequency patterns (fx) can be used to quantitatively map the anisotropic scattering phase function distribution (P(θs)) in turbid media. Monte Carlo simulations were used in part to establish a semi-empirical model of demodulated reflectance (Rd) in terms of dimensionless scattering (μ′sf−1x) and γ, a metric of the first two moments of the P(θs) distribution. Experiments completed in tissue-simulating phantoms showed that simultaneous analysis of Rd spectra sampled at multiple f …

Sensitivity Of Mri-Guided Near-Infrared Spectroscopy Clinical Breast Exam Data And Its Impact On Diagnostic Performance, Michael A. Mastanduno, Junqing Xu, Fadi El-Ghussein, Shudong Jiang, Hong Yin, Yan Zhao, Kelly E. Michaelson, Ke Wang, Fang Ren, Brian W. Pogue, Keith D. Paulsen

Dartmouth Scholarship

In this study, data from breast MRI-guided near infrared spectroscopy (NIRS) exams delivered to 44 patients scheduled for surgical resection (ending in 16 benign and 28 malignant diagnoses) were analyzed using a spatial sensitivity metric to quantify the adequacy of the optical measurements for interrogating the tumor region of interest, as derived from the concurrent MRI scan. Along with positional sensitivity, the incorporation of spectral priors and the selection of an appropriate regularization parameter in the image reconstruction were considered, and found to influence the diagnostic accuracy of the recovered images. Once optimized, the MRI/NIRS data was able to differentiate …

Optimization Of Imaging Parameters To Determine Flow Velocity Using Nanoparticles, Sabrina M. Scalf, Haisheng Yang, Russell P. Main

The Summer Undergraduate Research Fellowship (SURF) Symposium

Microfluidic flow chambers have been developed and used to measure flow at the microscopic level. Nanoparticles can be used to track the fluid flow within the chamber and this allows for accurate velocity measures. Microscope parameters used for experimentation differ across various projects and resources; therefore, there is a need to determine the best combination of settings for the equipment at hand. Once appropriate settings are selected, images of the flow are captured with a confocal microscope and can be analyzed using custom written MATLAB code. A pair cross-correlation function is used to determine where the particles have traveled in …

Three Dimensional Quantification Of Angiotensin Ii-Induced Murine Abdominal Aortic Aneurysms Using High Frequency Ultrasound, Amelia R. Adelsperger, Alexa A. Yrineo, Hilary D. Schroeder, Ashley Nicole Blaize, Katherine E. Wilson, Evan H. Phillips, Frederick W. Damen, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysms (AAAs), a localized dilation of the vessel wall of 50% or more above normal, claims approximately 14,000 U.S. lives yearly due to aortic rupture. This commonly asymptomatic disease can only be treated by endovascular stent grafts or invasive surgery, usually after the AAA diameter reaches 5 cm. Because these treatment methods carry serious risk, stem cell therapy is being explored in order to provide a low risk option for managing smaller AAAs. To determine if stem cell therapy, once administered, could stabilize or reduce AAA growth, baseline 3D ultrasound measurements in a control group were first needed. …

Nonlinear Optical Microscopy Of Murine Abdominal Aortic Aneurysm, Katherine E. Wilson, Alexa A. Yrineo, Amelia J. Adelsperger, Hilary D. Schroeder, Delong Zhang, Jesse Zhang, Chien-Sheng Liao, Frederick W. Damen, Ji-Xin Cheng, Evan H. Phillips, Craig J. Goergen

The Summer Undergraduate Research Fellowship (SURF) Symposium

Abdominal aortic aneurysm (AAA) is a cardiovascular disease characterized by dilation and weakening of the vessel wall. AAA rupture is responsible for approximately 14,000 deaths annually in the United States [1]. Nonlinear optical (NLO) microscopy presents new possibilities for analyzing AAA tissue samples from murine models. Common NLO techniques are two-photon excitation fluorescence (TPEF), which detects the intrinsic autofluorescent properties of elastin, and second-harmonic generation (SHG), which is specific for collagen fibrils. Elastin and collagen, two major extracellular matrix components, help the aortic wall withstand internal pressure. Murine AAAs were created through 1) subcutaneous continuous systemic infusion of angiotensin II …

Nerve Fiber Diameter Measurements Using Hematoxylin And Eosin Staining And Brightfield Microscopy To Assess The Novel Method Of Characterizing Peripheral Nerve Fiber Distributions By Group Delay, Jorge Arturo Vazquez

Master's Theses

Peripheral neuropathies are a set of common diseases that affect the peripheral nervous system, causing damage to vital connections between various parts of the body and the brain and spinal cord. Different clinical conditions are known to selectively impact various size nerve fibers, which often makes it difficult to diagnose which peripheral neuropathy a patient might have. The nerve conduction velocity diagnostic test provides clinically useful information in the diagnosis of some peripheral neuropathies. This method is advantageous because it tends to be minimally invasive yet it provides valuable diagnostic information. However, this test does not determine characteristics of peripheral …

Fluid Powered Miniature In Vivo Robots For Minimally Invasive Surgery (Mis), Abolfazl Pourghodrat

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Minimizing the invasiveness of surgery is believed to improve patient outcomes. Bleeding, infection, and pain are major concerns in surgery afflicting patients for decades. Minimally invasive techniques have come into play to reduce these concerns and smooth the evolution of abdominal surgery to a scarless process where nearly all surgeries can be performed without a skin incision. Technology continually advances the frontier of development of novel surgical devices to implement less invasive surgical techniques.

Fusion of robotics and Minimally Invasive Surgery (MIS) has created new opportunities to develop diagnostic and therapeutic tools. Surgical robotics is advancing from externally actuated systems …

Experimental Terahertz Imaging And Spectroscopy Of Ex-Vivo Breast Cancer Tissue, Tyler C. Bowman

Graduate Theses and Dissertations

This thesis presents experimental results of terahertz imaging and spectroscopy techniques to analyze excised breast cancer tissue. The pulsed terahertz system at the University of Arkansas was used to assess formalin-fixed, paraffin-embedded breast cancer tissue obtained from 22, 40, and 46 year old patients. The tissue for this research was sliced to relatively thin sections of 10 μm thick and mounted on glass slides. Terahertz reflection time and frequency domain images of the breast cancer tissue were then obtained and compared to histopathology slides from the same patient. Results showed good correlation between the reflection images and histopathology slides for …

Frontal White Matter Integrity In Adults With Down Syndrome With And Without Dementia, David K. Powell, Allison Caban-Holt, Greg A. Jicha, William C. Robertson, Roberta Davis, Brian T. Gold, Frederick A. Schmitt, Elizabeth Head

Magnetic Resonance Imaging and Spectroscopy Center Faculty Publications

Adults with Down syndrome (DS) are at high risk for developing Alzheimer's disease after the age of 40 years. To detect white matter (WM) changes in the brain linked to dementia, fractional anisotropy (FA) from diffusion tensor imaging was used. We hypothesized that adults with DS without dementia (DS n = 10), DS with dementia (DSAD n = 10) and age matched non-DS subjects (CTL n = 10) would show differential levels of FA and an association with scores from the Brief Praxis Test and the Severe Impairment Battery. WM integrity differences in DS compared with CTL were found predominantly …

Uncertainty Quantification Driven Predictive Multi-Scale Model For Synthesis Of Mycotoxins, Sourav Banerjee, Gabriel A. Terejanu, Anindya Chanda

Faculty Publications

Many toxic molds synthesize and release an array of poisons, termed mycotoxins that have an enormous impact on human health, agriculture and economy [1]. These molds contaminate our buildings, indoor air and crops, cause life threatening human and animal diseases and reduce agricultural output [2]. In order to design appropriate approaches to minimize the detrimental effects of these fungi, it is essential to develop diagnostic methodologies that can rapidly and accurately determine based on fungal strains and their growth patterns, the extent of mycotoxin mediated damage caused to the environment.Here we developed a novel multi-scale predictive mathematical model that could …

Developent Of A Phospholipid Encapsulation Process For Quantum Dots To Be Used In Biologic Applications, Logan Grimes

Master's Theses

The American Cancer Society predicts that 1,665,540 people will be diagnosed with cancer, and 585,720 people will die from cancer in 2014. One of the most common types of cancer in the United States is skin cancer. Melanoma alone is predicted to account for 10,000 of the cancer related deaths in 2014. As a highly mobile and aggressive form of cancer, melanoma is difficult to fight once it has metastasized through the body. Early detection in such varieties of cancer is critical in improving survival rates in afflicted patients. Present methods of detection rely on visual examination of suspicious regions …

Smooth Muscle Cell Organization In The Stem Region Of The Gracilis Collateral Circulation, Amanda Krall

Biomedical Engineering

Many patients who suffer from the ischemic Peripheral Arterial Occlusive Disease (PAOD) experience intermittent claudication, which can be attributed to impaired vasodilation. Collateral vessels are the primary site of resistance to blood flow downstream; therefore maximizing vasodilation in collaterals is crucial for efficient circulation. Collaterals function as natural bypasses around the occluded arteries and the increase in flow into these vessels causes them to outwardly remodel into conduit vessels. However, functional vasodilation in the stem region of collateral vessels is impaired at day 7 following femoral ligation, which can be attributed to smooth muscle cell malfunction. However, the increase in …

Extraction Of Intrinsic Fluorescence From Single Fiber Fluorescence Measurements On A Turbid Medium: Experimental Validation, U. A. Gamm, C. L. Hoy, F. Van Leeuwen - Van Zaane, H. J. C. M. Sterenborg, S. C. Kanick, D J. Robinson, A. Amelink

Dartmouth Scholarship

Abstract

The detailed mechanisms associated with the influence of scattering and absorption properties on the fluorescence intensity sampled by a single optical fiber have recently been elucidated based on Monte Carlo simulated data. Here we develop an experimental single fiber fluorescence (SFF) spectroscopy setup and validate the Monte Carlo data and semi-empirical model equation that describes the SFF signal as a function of scattering. We present a calibration procedure that corrects the SFF signal for all system-related, wavelength dependent transmission efficiencies to yield an absolute value of intrinsic fluorescence. The validity of the Monte Carlo data and semi-empirical model is …

Application Of Limited Mixing In The Hele–Shaw Geometry In Fabrication Of Janus Hydrogels, Md Mahmudur Rahman

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

It is widely accepted that cells behave differently responding to the stiffness of their extracellular matrix (ECM). Such observations were made by culturing cells on hydrogel substrates of tunable stiffness. However, it was recently proposed that cells may sense how strongly they are tethered to ECM, not the local stiffness of ECM. To investigate both hypotheses, we developed a method to fabricate Janus polyacrylamide (PAAM) gels. We squeeze two drops of different concentrations in the Hele-Shaw geometry to generate radial Stokes flow. When the drops coalesce, limited mixing occurs at the interface due to the narrow confinement, and diffusion normal …

Material Differences In Equine Cortical And Trabecular Bone, Ryan B. Allen

Master's Theses

A greater understanding of bone materials would be beneficial in creating more accurate computer models and in the making of biomedical products involving bone. This study set out to determine whether cortical and trabecular bone are two separate materials, or whether they are the same material with a variance in porosity. To answer this question, samples were taken from different sections of the equine metacarpus, underwent densitometry analysis and were statistically analyzed. The majority of results suggest that the material is the same between varying densities of bone and thus the same between cortical and trabecular bone. These particular results …