Search Results (1 - 25 of 51 Results)

Sort By  
Sort Dir
 
Results per page  

Spaw, Alexandra J.Fetal Developmental Anatomy of the Human Cardiovascular and Central Nervous Systems Using Lugol’s Iodine Staining and Micro-Computed Tomography
Bachelor of Science (BS), Ohio University, 2014, Biological Sciences
Iodine staining with Lugol’s solution is a fast-developing technique that is revolutionizing imaging studies, because it provides the opportunity to distinguish between soft tissues through soaking of the specimen followed by computed tomography (CT scanning). Earlier protocols that resulted in marked tissue shrinkage have been modified by treating specimens with a buffered sucrose solution prior to staining with isotonic Lugol’s, yielding excellent results. This technique was used to compare the cardiovascular and central nervous systems of a series of human fetal specimens ranging in age from six weeks to 28 weeks. For this study, four specimens were analyzed that were initially labeled six weeks, 10-12 weeks, 12-14 weeks, and 16 weeks; the justification for these ages were unknown, and new gestational ages were estimated using multiple measures resulting in new age estimates of 8.5 weeks, 12.5 weeks, 13 weeks, and 15 weeks. Specimens were microCT scanned prior to soaking in Lugol’s iodine and then rescanned after soaking to compare size-related parameters and soft-tissue resolution. Anatomical structures were analyzed and segmented using the computer program Avizo, providing the basis for the generation of labeled images, 3D reconstructions, 3D interactive PDFs, movies, and other forms of digital representations of the information provided in the CT scan data. Results include all representations which lead to a catalog of developing anatomy from the late embryonic stage well into the fetal stage of gestation. The specimens analyzed showed mostly normal anatomy for their respective ages and demonstrate fetal landmarks of the organ systems in focus (e.g., ductus arteriosus, foramen ovale, and spinal cords extending farther caudally than in neonates or adults). However, the youngest specimen (8.5 weeks) demonstrated a suspected anomaly which appears to be a schizencephaly, possibly revealing the cause of death. The catalog created provides students and educators with multiple forms of media to study the fetal anatomy of these two systems and allows professionals to better visualize and interact with the reconstructed versions of key organ systems. The study of both normal and teratological anatomy will lead to greater knowledge of any defects and could potentially lead to improved treatment and surgical plans.

Committee:

Lawrence Witmer, PhD (Advisor)

Subjects:

Anatomy and Physiology; Biomedical Research; Developmental Biology; Medical Imaging; Radiology; Scientific Imaging

Keywords:

developmental anatomy; Lugols iodine; fetal anatomy; birth defects; anatomy education; micro-CT scanning;

Van Hook, Richard L.A Comparison of Monocular Camera Calibration Techniques
Master of Science in Computer Engineering (MSCE), Wright State University, 2014, Computer Engineering
Extensive use of visible electro-optical (visEO) cameras for machine vision techniques shows that most camera systems produce distorted imagery. This thesis investigates and compares several of the most common techniques for correcting the distortions based on a pinhole camera model. The methods being examined include a common chessboard pattern based on (Sturm 1999), (Z. Zhang 1999), and (Z. Zhang 2000), as well as two "circleboard" patterns based on (Heikkila 2000). Additionally, camera models from the visual structure from motion (VSFM) software (Wu n.d.) are used. By comparing reprojection error from similar data sets, it can be shown that the asymmetric circleboard performs the best. Finally, a software tool is presented to assist researchers with the procedure for calibration using a well-known fiducial.

Committee:

Kuldip Rattan, Ph.D. (Advisor); Juan Vasquez, Ph.D. (Committee Member); Thomas Wischgoll, Ph.D. (Committee Member)

Subjects:

Computer Engineering; Computer Science; Optics; Scientific Imaging

Keywords:

Calibration; Reprojection Error; Visual Structure from Motion; OpenCV; calibration patterns

Vogt, Keith M.Optimization of physiologic noise correction in functional magnetic resonance imaging
Doctor of Philosophy, The Ohio State University, 2009, Biomedical Engineering

Though in widespread clinical and research use as a tool to evaluate brain function, functional magnetic resonance imaging (FMRI) data is severely contaminated by noise, due in large part to physiologic noise caused by respiratory and cardiac variations over time. This dissertation attempts to better characterize several physiologic noise correction techniques applied to pain FMRI data. Three studies are described that collectively work toward determining an optimal physiologic noise correction algorithm to be used in future pain FMRI studies.

First, a novel algorithm, RetroSLICE, is described that uses linear regression to correct acquired images for signal intensity fluctuations correlated to measured respiratory, cardiac, and capnometry variations. The impact of this technique was assessed for a 1.5 T pain FMRI experiment. Each physiologic noise regressor used as a part of the RetroSLICE algorithm independently resulted in a decrease in timecourse variance and an improvement in model fit. Combined correction for the instantaneous effects of respiratory and cardiac variations caused a 5.4% decrease in signal variance and increased model fit (mean R2a) by 65%. The addition of ETCO2 correction as part of the general linear model led to 39% further improvement in model fit. Each of these corrections also caused changes in the group activation map.

Next, an optimal transfer function between ETCO2 level and BOLD signal changes was empirically determined using FMRI data in which paced breathing forced a 35% decrease in ETCO2. ETCO2 data convolved with this optimized response function was compared to another measure, the respiratory volume over time (RVT) convolved with an optimized respiration response function. When regressed against FMRI data collected during a breathing modulation task, ETCO2 was more strongly and diffusely correlated to the data than RVT. Conversely, when the same comparative analysis was performed on pain FMRI data, RVT was more strongly correlated than ETCO2. In both cases, allowing ± 2 s flexibility in the response function peak times did not change the relative correlation to the MR data of the ETCO2 compared to the RVT timecourses.

Finally, the well-known physiologic noise correction algorithm, RETROICOR, was implemented on pain FMRI data collected at 1.5 and 3.0 T. Respiratory and cardiac correction with Fourier series phase fitting caused an 8.2% decrease in signal variance and a 227% increase in model fit at 1.5 T, indicating performance superior to RetroSLICE. At 3.0 T, significantly greater improvements were seen: a 10.4% decrease in signal noise and 240% increase in mean R2a. ETCO2 correction applied with the optimized response function previously determined caused insignificant changes in noise reduction and model fit. Further exploration of the properties of the RETROICOR algorithm showed no difference in impact when applied with physiologic input data sampled at a much higher rate or when accounting for the interleaved slice acquisition order. These findings suggest that RETROICOR should be included as a part of the physiologic noise correction procedure in pain FMRI studies at 1.5 and 3.0 T.

Committee:

Petra Schmalbrock, PhD (Advisor); Robert Small, MD (Committee Chair); Cynthia Roberts, PhD (Committee Member); Alan Litsky, MD,ScD (Committee Member)

Subjects:

Engineering; Radiology; Scientific Imaging

Keywords:

functional MRI; brain; pain; physiologic noise correction; RETROICOR; RetroSLICE; ETCO2

Ducay, Rey Nann Mark AbaqueDirect Detection of Aggregates in Turbid Colloidal Suspensions
Master of Science, Miami University, 2015, Physics
This thesis presents the application of an empirical model of total internal reflection (TIR) we recently developed in conjunction with a home-built sensor to detect nanoaggregates in highly scattering opaque polystyrene colloidal suspensions. The nanoaggregates are detected directly without any sample dilution or special sample preparation. Additional results on nanoaggregate detection in gold nanoparticle suspensions are presented. Preliminary tests of our model and sensor in an absorbing dye solution are also presented.

Committee:

Samir Bali, PhD (Advisor); Lalit Bali, PhD (Advisor); Jason Berberich, PhD (Advisor); Jon Scaffidi, PhD (Advisor); James Clemens, PhD (Committee Member); Karthik Vishwanath, PhD (Committee Member)

Subjects:

Analytical Chemistry; Biochemistry; Biomedical Engineering; Biomedical Research; Biophysics; Chemical Engineering; Chemistry; Experiments; Materials Science; Medical Imaging; Molecular Physics; Molecules; Nanoscience; Nanotechnology; Optics; Organic Chemistry; Physics; Polymer Chemistry; Polymers; Scientific Imaging

Keywords:

Nanoparticles; nanoparticle aggregation; empirical model; gold nanoparticles; polystyrene nanoparticles; microspheres; turbid media; TIR; total internal reflection; biosensors; highly-scattering; nanoaggregation sensing; DLS; UV-Vis; DLVO; Zeta potential

Ryan, Christopher JamesThree Dimensional Data Storage in Polymeric Systems
Doctor of Philosophy, Case Western Reserve University, 2012, Physics
Since the late 1980s optical data storage has been a staple for the circulation of digital information. Through the years the storage capacity of these devices has grown to match new demands and applications. However, fundamental optical limitations exist which inhibit the growth of the current paradigm of devices. This work is comprised of experiments and demonstrations related to new optical data storage techniques. Various results are presented to augment and optimize future iterations of such devices. Most notably, a 64 layer disk is fabricated and used to store data. This device is fashioned using a polymer coextrusion technique and stores information at a high density on 23 of its 64 fluorescent layers. To understand the significance of such devices, a simulation is used to quantify the benefits of multilayered storage disks over monolithic devices. Noise is shown to be drastically reduced in multilayered structures, while the signal contrast grows under the influence of confinement effects. In the process of making this device, an aggregrochromic dye was chosen as a candidate material. Further experiments characterize how the dye changes phases as a response to photopatterning. As presented, these projects cite specific issues with optical data storage technology and offer options for complexity and growth within the field. Also presented is an unrelated experiment which determines the dimensionality of the exciton-exciton interaction in Zinc Phthalocyanine.

Committee:

Jie Shan (Advisor); Kenneth Singer (Committee Member); Rolfe Petschek (Committee Member); Lei Zhu (Committee Member)

Subjects:

Condensed Matter Physics; Optics; Physics; Plastics; Polymers; Scientific Imaging

Keywords:

Optical Data Storage; Multilayer; coextrusion; phthalocyanine; exciton dynamics; biexciton; annihilation; exciton-exciton; nonlinear absorption; photopatterning

Murad, Mark RichardRadiation View Factors Between A Disk And The Interior Of A Class Of Axisymmetric Bodies Including Converging Diverging Rocket Nozzles
Master of Science in Mechanical Engineering, Cleveland State University, 2008, Fenn College of Engineering

A general symbolic exact analytic solution is developed for the radiation view factors including shadowing by the throat between a divergence thin gas disk between the combustion chamber and the beginning of the rocket nozzle radiating energy to the interior downstream of the nozzle contour for a class of coaxial axisymmetric converging diverging rocket nozzles. The radiation view factors presented in this thesis for the projection which are blocked or shadowed through the throat radiating downstream to the contour have never been presented before in the literature.

It was found that the curvature of the function of the contour of the nozzle being either concave up or down and the slope of the first derivative being either positive or negative determined the values used for the transformation of the Stokes Theorem into terms of x, r (radius) and f(x) for the evaluation of the line integral.

The analytical solutions from the view factors of, for example, the interior of a combustion chamber, or any radiating heat source to a disk may then be applied to the solution of the view factor of the disk to the interior of the rocket nozzle contour presented here. This modular building block type approach is what the author desires to allow the development of an interstellar matter antimatter rocket engine. The gases of this type of reaction shall approach those towards the speed of light, which shall involve a transport phenomena, which the author is looking forward to researching the solution.

Committee:

Asuquo Ebiana, PhD (Advisor); Majid Rashidi, PhD (Committee Member); John Frater, PhD (Committee Member); John Oprea, PhD (Committee Member)

Subjects:

Aerospace Materials; Astrophysics; Chemical Engineering; Computer Science; Electromagnetism; Engineering; Gases; Materials Science; Mathematics; Mechanical Engineering; Nuclear Chemistry; Nuclear Physics; Radiation; Radiology; Scientific Imaging; Transportation

Keywords:

shadowing; radiation view factor; rocket nozzle: cooling; radiation heat transfer; differential geometry; configuration factor

Fennimore, Todd F.Understanding change in medicine and the biomedical sciences: Modeling change as interactions among flows with arrow diagrams
Master of Arts, Case Western Reserve University, 2011, Cognitive Linguistics
Building on Aristotle’s analysis, this thesis starts with a definition of change as the result of a network of influences operating to shape a particular outcome in manifesting a potential. It argues that change can be modeled as an interaction among flows, and that arrow diagrams are effective tools for such modeling. The thesis demonstrates how the phenomenology, ontology, and dynamics of change are prompted in the interpretation of arrow diagrams. A typology is presented that emerged from a corpus analysis of arrow diagrams sampled from medical and biomedical journals. In Chapter 2, the typology is applied to the analyses of arrow diagrams from this corpus. In Chapter 3, I propose that a systematic treatment of ways in which arrow diagramming are used to model change can become the basis for a new field that I dub “fluxemics.” Moving forward, this idea will be developed mathematically and tested empirically.

Committee:

Per Aage Brandt, PhD (Advisor); Peter Whitehouse, MD/PhD (Committee Member); Mark Turner, PhD (Committee Member)

Subjects:

Scientific Imaging; Systems Science

Keywords:

scientific reasoning; explanation; diagramming; cognitive science; modeling of change

Chang, HanaToward Clinical Stem Cell Sourcing And Definition Of Prescriptive Biophysical Protocols To Guide Stem Cell Fate During Healing
Doctor of Philosophy, Case Western Reserve University, 2013, Biomedical Engineering
Current stem cell and tissue engineering R&D aim to initiate and guide de novo tissue generation for the repair or replacement of native tissue compromised due to injury, disease, or other disorders. Biophysical cues present a safe and controllable means to modulate cell behavior and emergent cell fate. Scaling up from cellular to systems length scales, there is great future potential for prescriptive physical therapies that synergistically promote healing in conjunction with approaches including stem cell based regenerative tissue engineering and next generation implants cum delivery devices. This dissertation addresses key obstacles for biophysically-enhanced de novo tissue generation by (i) examining the potential of the femoral neck periosteum in discarded tissue from arthritic patients undergoing hip replacement surgery as a feasible source of adult stem cells for tissue engineering, (ii) unraveling the emergent spatial and temporal mechanoadaptive structure – function relationships of stem cells after exposure to volume and shape changing stresses, (iii) and implementing a coupled computational fluid dynamics and finite element method model to define future experiments to test the ability of mechanical cues to guide stem cell fate during healing. Addressing the first aim, an IRB approved study highlighted the potential of femoral neck periosteum as a new source for stem cell acquisition and banking of autologous multipotent cells for middle aged to aging individuals. The second aim, to unravel emergent anisotropy in model embryonic mesenchymal stem cell structure and nascent lineage commitment, showed that the actin and tubulin cytoskeleton exhibit emergent anisotropy in the apical-basal direction and that these changes correlate to regulation of transcription factors indicative of fate. Finally, the third aim addresses a parametric approach using a CFD-FEM model to predict the local normal and shear stresses at cell-fluid interfaces in a tissue template within the controlled environment of a perfusion chamber, expanding on a previous study to achieve efficient validation of the model by defining libraries of mechanical cues that can be delivered prospectively to guide stem cell fate. Taken together, this body of work supports the possibility of developing biophysically-guided tissue templates or tissue engineering constructs designed to facilitate de novo tissue generation and healing.

Committee:

Melissa Knothe Tate (Advisor); Edward Greenfield (Committee Member); Daniela Calvetti (Committee Member); Eben Alsberg (Committee Member)

Subjects:

Biomechanics; Biomedical Engineering; Biomedical Research; Cellular Biology; Developmental Biology; Engineering; Mechanical Engineering; Medicine; Molecular Biology; Scientific Imaging

Keywords:

periosteum; stem cell; tissue engineering; stem cell; mechanics; mechanoadaptation; emergence; fate; lineage commitment; model; cell perfusion; mechanome

DICK, ERIC TIMOTHYA Survey of CT Phantom Considerations for the Study of Blooming Artifacts as Observed in CT Coronary Angiography Studies: A Preliminary Study
MS, University of Cincinnati, 2008, Medicine : Radiology-Radiological Sciences (Medical Physics)
The presence of image "blooming" artifacts, in particular with respect to highly calcifiedplaques, has been a major impediment to the implementation of Multi-detector Computed Tomography (MD-CT) as an alternative to standard angiography in routine clinical practice. A beam hardening phantom system was developed to determine the dependence of blooming with respect to measured density in Hounsfield Units (HU), of 5mm diameter plaques. Custom software was developed to provide reproducible objective measurements of plaque size. Plaque diameter was measured using a series of axially distributed profiles centered on the object. Reconstruction blur was shown to be a significant, density dependent contributor to standard clinical blooming measurements. Beam hardening was shown to not affect measurements of sample diameter in a blur corrected study. Furthermore, two additional phantom designs have been proposed and evaluated for the future study of partial volume and cone beam affects on blooming.

Committee:

Lisa Lemen, PhD (Committee Chair); Elson Howard, PhD (Committee Member); Lamba Michael, PhD (Committee Member)

Subjects:

Radiation; Radiology; Scientific Imaging

Keywords:

blooming; computed tomography; artifact; CT; beam hardening; partial volume averaging;cone beam

Foose, Daniel PatrickVespucci: A free, cross-platform software tool for spectroscopic data analysis and imaging
Master of Science (MS), Wright State University, 2016, Chemistry
Vespucci is a software application developed for imaging and analysis of hyperspectral datasets. Vespucci offers several advantages over other software packages, including a simple user interface, no cost, and less restrictive licensing. Vespucci incorporates several analysis techniques including univariate imaging, principal components analysis, partial-least-squares regression, vertex components analysis and k- means clustering. Additionally, Vespucci can perform a number of useful data-processing operations, including filtering, normalization, baseline correction, and background subtraction. Datasets that consist of spatial or temporal data with a corresponding digital signal, including spectroscopic images, mass spectrometric images, and X-ray diffraction data can be processed in this software. The use of Vespucci in Raman and surface- enhanced Raman spectroscopies has been successfully demonstrated to examine the interaction of silver nanoparticles with corundum and Dengue virus virions. A manuscript detailing Vespucci has been published in the Journal of Open Research Software (http://openresearchsoftware.metajnl.com/articles/10.5334/jors.91/). More information about Vespucci will be available at http://vespucciproject.org.

Committee:

Ioana Sizemore, Ph.D. (Advisor); David Dolson, Ph.D. (Committee Member); Michael Raymer, Ph.D. (Committee Member)

Subjects:

Biology; Biomedical Engineering; Biomedical Research; Chemical Engineering; Chemistry; Environmental Science; Materials Science; Medical Imaging; Molecular Biology; Nanotechnology; Pharmacology; Physics; Physiology; Polymer Chemistry; Polymers; Remote Sensing; Scientific Imaging; Statistics; Toxicology; Virology

Keywords:

chemometrics; cheminformatics; bioinformatics; spectroscopy; Raman spectroscopy; software; scientific software; data analysis

Heise, Erich ADevelopment and Commercialization of Functional, Non-Invasive Retinal Imaging Device Utilizing Quantification of Flavoprotein Fluorescence for the Diagnosis and Monitoring of Retinal Disease
Master of Sciences, Case Western Reserve University, 2016, Biology
Diabetes and its related complications are becoming increasingly more prevalent in the United States and other developed countries. Additionally, an increasingly earlier age of onset results in more complications, such as diabetic retinopathy, leading to increased annual medical costs and poorer quality of life. Therefore, the ability to rapidly and non-invasively detect diabetes and other retinal diseases at the earliest stages is critical to saving patients’ vision and improving their overall quality of life. Retinal metabolic analysis, a measure that the detects the fluorescence of flavoproteins critical to ATP generation, allows ophthalmologists and optometrists to identity retinal diseases earlier in the disease process and intervene before irreversible tissue damage and loss of visual acuity occurs.

Committee:

Christopher Cullis, PhD (Advisor); Jessica Fox, PhD (Committee Member); Leena Chakravarty, PhD (Committee Member); Ryan Martin, PhD (Committee Member)

Subjects:

Biochemistry; Biology; Biomedical Engineering; Biophysics; Cellular Biology; Entrepreneurship; Health; Medical Imaging; Ophthalmology; Scientific Imaging

Keywords:

flavoprotein fluorescence; retinal metabolic analysis; OcuSciences; functional retinal imager; biotechnology; retinal imaging; FPF

Jung, Young WooOptical studies and biological applications of spins in semiconductors
Doctor of Philosophy, The Ohio State University, 2011, Physics
Control of electronic spins in paramagnetic systems opens new avenues for the next generation of logic and memory devices. It also gives us new opportunities in biomedical applications such as nano-MRI. Polarization of spins in optically-active paramagnetic materials, such as gallium arsenide (GaAs), is achieved by optical pumping and the system can be manipulated using an external magnetic field or microwave radiation. The status of these spins is detected by measurement of photoluminescence. Specifically, The spin relaxation time of bulk and membrane GaAs were studied via the Hanle effect, in which spins are made to precess by a perpendicular external field. This work laid a foundation for developing a material non-specific spin detection technique for paramagnetic materials, like silicon, which combines optical detection with magnetic scanned probe. Additionally, we studied the multiferroic properties of europium titanate on dysprosium scandate which is a new class of multiferroic material whose properties are controlled by strain engineering. Europium titanate on dysprosium scandate could be used for spintronic applications, such as multiferroic memories in the future using its magnetoelectric coupling. Finally, this thesis focuses on studies of localized electron spins of negatively charged nitrogen-vacancy (NV) centers in diamond using optical detection and their applications to bio-molecular studies. The spins of localized electrons of NV centers can be polarized, manipulated and detected by optically detected magnetic resonance (ODMR) with a high resolution. These unique spin properties can be used to develop highly sensitive vector magnetometry. This thesis presents the successful development of the scanning vector field magnetometry using the NV centers in diamond and concludes by surveying the possible applications to biological systems.

Committee:

P. Chris Hammel, Dr. (Advisor); Ezekiel Johnston-Halperin, Dr. (Committee Member); William Putikka, Dr. (Committee Member); Richard Kass, Dr. (Committee Member)

Subjects:

Biophysics; Condensed Matter Physics; Experiments; Nanotechnology; Optics; Physics; Quantum Physics; Scientific Imaging

Keywords:

spin injection; galium arsenide; multiferroics; europium titanate; magneto optical kerr effect; nitrogen-vacancy center; diamond; photoluminescence; optically detected magnetic resonance; magnetometry; nanodiamond; DNA dynamics; magnetotactic bacteria

Crotty, MaureenSignal to Noise Ratio Effects on Aperture Synthesis for Digital Holographic Ladar
Master of Science (M.S.), University of Dayton, 2012, Electro-Optics
The cross-range resolution of a laser radar (ladar) system can be improved by synthesizing a large aperture from multiple smaller sub-apertures. This aperture synthesis requires a coherent combination of the sub-apertures; that is, the sub-apertures must be properly phased and placed with respect to each other. One method that has been demonstrated in the literature to coherently combine the sub-apertures is to cross-correlate the speckle patterns imaged in overlapping regions. This work investigates the effect of low signal to noise ratio (SNR) on an efficient speckle cross-correlation registration algorithm with sub-pixel accuracy. Specifically, the algorithms ability to estimate relative piston and tilt errors between sub-apertures at low signal levels is modeled and measured. The effects of these errors on image quality are examined using the modulation transfer function (MTF) as a metric. The results demonstrate that in the shot noise limit, with signal levels as low as about 0.02 signal photoelectrons per pixel in a typical CCD, the registration algorithm estimates relative piston and tilt accurately to within 0.1 radians of true piston and 0.1 waves of true tilt. If the sub-apertures are not accurately aligned in the synthetic aperture, then the image quality degrades as the number of sub-apertures increases. The effect on the MTF is similar to the effects due to defocus aberrations.

Committee:

Edward Watson, PhD (Advisor); Matthew Dierking, PhD (Committee Member); David Rabb, PhD (Committee Member)

Subjects:

Engineering; Optics; Remote Sensing; Scientific Imaging

Keywords:

LADAR; Synthetic Aperture Registration; SNR; Speckle Cross-Correlation; MTF; Spatial Heterodyne

Kuang, YuPositron Emission Tomography Imaging of Hepatocellular Carcinoma with Radiolabeled Choline
Doctor of Philosophy, Case Western Reserve University, 2009, Biomedical Engineering
Hepatocellular Carcinoma (HCC) is one of the most common malignancies throughout the world and its five-year survival rate has been dismal (5%). The carcinogenesis is frequently associated with the metabolic changes that precede the morphological changes. Therefore, a non-invasive, fast, quantitative technique for detection of HCC is much needed. Positron emission tomography (PET), a molecular imaging technique, holds particular promise for diagnostic imaging of neoplasms. The focus of this thesis is on the diagnostic utility of PET metabolic imaging on HCC and the mechanisms underlying the imaging using radiolabeled choline (CHOL) as the tracer. (1) Many cancers display a high rate of aerobic glycolysis, a phenomenon that is exploited by 2-Deoxy-2-[18F]-fluoro-D-glucose (FDG) PET imaging for the detection of tumors. Up-regulation of glycolytic metabolism plays a role in tumor progression by contributing to tumor growth or survival. In this study, the usefulness of FDG-PET for HCC was investigated. The study addressed the correlation between FDG-PET images with pathologic types of HCC. The overall sensitivity of FDG-PET in the detection of HCC is low (50-55%). This can be explained by the wide variability in enzyme activity in the individual HCC. In well-differentiated HCC, FDG metabolism may be similar to that of the surrounding liver, leading to a false negative result, while higher sensitivity was reported in poorly differentiated HCC. (2) Increased lipid synthesis is required by a growing tumor cell to synthesize membranes and lipid-modified signaling molecules. The radiolabeled choline (CHOL) was used to probe lipid synthesis in HCC. In this study, PET/CT imaging was correlated with metabolites analysis in vivo and in vitro, which helps to explain the heterogenous uptake of radiolabeled CHOL in HCC. Transport and phosphorylation of CHOL are responsible for the tracer accumulation during [11C]-CHOL PET imaging in well-differentiated HCC. Moreover, basal oxidation and phosphorylation activities in surrounding hepatic tissue contribute to the background signal seen in [11C]-CHOL PET images. Furthermore, PET imaging of lipid synthesis with radiolabeled CHOL is useful in well-differentiated HCC that is not FDG avid. PET/CT imaging with radiolabeled CHOL could thus be a very promising diagnostic tool in patients with suspicious liver masses.

Committee:

Zhenghong Lee, Ph.D. (Advisor); David Wilson, Ph.D. (Committee Chair); Thomas Kelley, Ph.D. (Committee Member); Xin Yu, Sc.D. (Committee Member)

Subjects:

Biochemistry; Engineering; Health; Radiology; Scientific Imaging

Keywords:

Hepatocellular Carcinoma; Positron Emission Tomography (PET); [11C]-choline; Molecular imaging; FDG; Cancer Metabolism; Transport mechanism; Phosphatidylcholine synthesis; Lipids; High performance liquid chromatography

Flanagan, Shawn DNeurological Basis of Persistent Functional Deficits after Traumatic Musculoskeletal Injury
Doctor of Philosophy, The Ohio State University, 2016, Kinesiology
Traumatic musculoskeletal injury is associated with chronic functional deficits that may result from changes in brain function and structure. The neurological underpinnings of such maladaptive responses are unknown and clarification will likely require the use of multimodal neuroscientific techniques that perturb and measure brain activity with high temporal and spatial resolution. The purpose of this investigation was to produce a neurological map of knee function under resting and active conditions, including the identification of brain circuits affected by traumatic musculoskeletal injury. Twenty-three women (N=23, age 21±3yr, weight 65.8±8.8kg, height 165.2±6.2cm) volunteered to participate in a series of mixed methods experiments. Ten subjects experienced unilateral anterior cruciate ligament (ACL) rupture and reconstruction six months to five years prior to the study (3.1±1.1yr). Thirteen age-, height-, weight-, handedness-, and footedness-matched participants served as controls. The neurological basis of persistent functional deficits was examined on three separate occasions with transcranial magnetic stimulation, tests of physical performance, and functional magnetic resonance imaging. Comparisons of corticospinal, functional, and hemodynamic responses were made between the injured and uninjured leg of subjects with traumatic injury and controls with no history of lower body injury. At rest, leg injury was associated with a reduction in the excitability of the motor cortical circuits governing the injured leg. Injury was also associated with lower maximal force production in the injured leg and a reduction force asymmetry compared to controls. Altered sensorimotor functions included impaired development of fine motor skill and a trend of proprioceptive loss with increased reliance on visual inputs. Imagined use of the injured leg during a task that challenged executive function increased activity in the respective sensorimotor regions to a lesser extent compared with controls. Most notably, activity in the right dorsolateral prefrontal cortex (dlPFC) increased more in injured participates and the magnitude was proportional to the extent of injured leg use. In summary, we observed long-term bilateral impairments in various measures of performance after traumatic musculoskeletal injury. Deficits were associated with alterations in the corticospinal circuits that govern the legs. Moreover, we present evidence to suggest such changes may partially reflect alterations in salience or motivation produced in the prefrontal association cortex. Pharmacological, electromagnetic, or behavioral therapies that favorably modulate such activity represent attractive candidates for the improvement of long-term outcomes and recovery during rehabilitation.

Committee:

William Kraemer (Advisor); James Onate (Committee Member); Jeff Volek (Committee Member); Carl Maresh (Committee Member)

Subjects:

Anatomy and Physiology; Biology; Electromagnetism; Experiments; Health Sciences; Kinesiology; Medical Imaging; Neurobiology; Neurology; Neurosciences; Physical Therapy; Physiology; Psychobiology; Rehabilitation; Scientific Imaging; Sports Medicine

Keywords:

Transcranial Magnetic Stimulation; functional magnetic resonance imaging; musculoskeletal injury; physical performance; neuroplasticity; central nervous system; neurophysiology; neuroscience; anterior cruciate ligament

Teeling-Smith, Richelle MarieSingle Molecule Electron Paramagnetic Resonance and Other Sensing and Imaging Applications with Nitrogen-Vacancy Nanodiamond
Doctor of Philosophy, The Ohio State University, 2015, Physics
Electron paramagnetic resonance (EPR) is an established and powerful tool for studying atomic-scale biomolecular structure and dynamics. Yet it requires a homogeneous sample size of approximately 10^15 spin-labeled biomolecules. In contrast, single molecule measurements provide improved insights into heterogeneous behaviors that can be masked by ensemble measurements and are often essential for illuminating the molecular mechanisms behind the function of a biomolecule. In this dissertation, I report EPR measurements of a single labeled biomolecule demonstrating the merging of these two powerful techniques. We have selectively labeled individual double-stranded DNA molecules with nanodiamonds containing nitrogen-vacancy (NV) centers, and optically detected the paramagnetic resonance of the NV nanodiamond probe. Analysis of the spectrum reveals that the characteristic time scale for reorientation of the labeled molecule relative to the applied magnetic field is slow compared to the spin relaxation time of the nanodiamond probe. This demonstration of EPR spectroscopic determination of the dynamics of an individual labeled biomolecular construct provides the foundation for single molecule magnetic resonance studies of complex biomolecular systems. In addition to this single-molecule EPR study, I report on the use of the NV center in diamond as a probe for in-vivo magnetometry, in-vivo fluorescence imaging and temperature sensing, and a tool for the measure of spin resonances in neighboring systems. The NV center in diamond has proven to be powerful tool for sensing and imaging in various systems, with a broad array of undeveloped or underdeveloped applications. The studies included in this dissertation provide a brief overview of a select few experiments that explore these capabilities.

Committee:

P. Chris Hammel (Advisor); Ezekiel Johnston-Halperin (Committee Member); Michael G. Poirier (Committee Member); Ralf Bundschuh (Committee Member)

Subjects:

Biochemistry; Biophysics; Condensed Matter Physics; Molecular Physics; Nanoscience; Nanotechnology; Optics; Physics; Scientific Imaging

Keywords:

NV diamond; Nitrogen-Vacancy Diamond; EPR; Electron Paramagnetic Resonance; DNA; DNA dynamics; confocal microscopy; single molecule spectroscopy; single-molecule measurements; biophysics; biomolecular dynamics; ODMR; Optically detected magnetic resonance

Ballard, Brett S.Feature Based Image Mosaicing using Regions of Interest for Wide Area Surveillance Camera Arrays with Known Camera Ordering
Master of Science (M.S.), University of Dayton, 2011, Electrical Engineering
Today, modern surveillance systems utilizing camera arrays can capture several square miles of ground activity at high resolution from a single aircraft. A camera array uses multiple cameras to capture images synchronously with partial overlap between cameras' fields of view. This allows a wide area to be monitored continuously in real time by image analysts or processed for information such as object identification and location tracking. The task of combining these images from each individual camera into one large image containing all of the images' views of the scene activity is commonly called image mosaicing in the field of computer vision. Though the process of image mosaicing is not new, what makes image mosaicing a topic of current research is the difficulty and variety of both problems and solutions. The objective of this thesis is to demonstrate the most suitable system to mosaicing images captured by wide area surveillance camera arrays with known camera ordering by using regions of interest combined with a feature based approach. The proposed system utilizes algorithms for feature extraction, matching, and estimation. The key difference between the proposed mosaicing system and prior successful mosaicing systems within other application domains is the use of known camera ordering. In many previously researched mosaicing systems no assumption is made for camera order, and in fact in some applications there is no assumption that images may even be viewing the same scene at all. However, for applications involving wide area surveillance camera arrays these assumptions are perfectly valid. This allows bounded regions of interest near the appropriate image borders to be used which is demonstrated in the proposed system to increase performance in both pixel accuracy and mosaic computation times over the more generalized mosaicing approach.

Committee:

Eric Balster, PhD (Committee Chair); Vijayan Asari, PhD (Committee Member); John Loomis, PhD (Committee Member)

Subjects:

Electrical Engineering; Remote Sensing; Scientific Imaging

Keywords:

regions of interest; roi; known camera ordering; image mosaicing; feature based homography; image stitching; stereo computer vision; wide area surveillance; camera array;

Zahedi, ShadiAre Mitochondria a Potential Target for Anti-Cancer Therapy in Carcinoid Tumors?
Master of Science in Biomedical Sciences (MSBS), University of Toledo, 2010, College of Medicine
Gastrointestinal (GI) carcinoids are slow growing malignancies of neuroendocrine phenotype that can behave aggressively. To date, there are no effective therapies for metastatic carcinoid cancer. Previous work by our lab and others has shown that carcinoids express variety of voltage-operated (VOCCs) and non-voltage-operated Ca2+ channels to allow Ca2+ to enter the cell. Although, the role of Ca2+ entry in these tumors is not well understood, previous work by our group and others has shown that mitochondria are important regulators of voltage-operated and non-voltage-operated Ca2+ entry. In addition, cancer cells typically exhibit mitochondrial dysfunction and poor anti-oxidant status. These observations and the central role that mitochondria play in metabolism, Ca2+ homeostasis and cell death pathways make mitochondria an appealing potential target for anti-cancer treatment in carcinoid tumors. We used an spectrum of human cancer cell lines and a variety of microfluorescence methods including wide-field, confocal, and total internal reflection (TIRF) microscopy to assess Ca2+ signaling and mitochondrial function in combination with pharmacological interventions to assay whether mitochondria are a potential target for anti-cancer therapy. To this end, we tested the effectiveness of an oxidant therapy approach in carcinoid cells.

Committee:

David Giovannucci, Ph.D. (Committee Chair); Andrew Beavis, Ph.D. (Committee Member); Vazquez Guillermo, Ph.D. (Committee Member)

Subjects:

Biomedical Research; Molecular Biology; Scientific Imaging

Keywords:

carcinoid tumors; mitochondrial; calcium signaling; TIRF microscopy; oxidant therapy; vitamin K3; vitamin C

Ausdenmoore, Benjamin D.Synaptic contact localization in three dimensional space using a Center Distance Algorithm
Master of Science (MS), Wright State University, 2011, Physiology and Neuroscience
Spatial distribution of synaptic inputs on the dendritic tree of a neuron can have significant influence on neuronal function. Consequently, accurate anatomical reconstructions of neuron morphology and synaptic localization are critical when modeling and predicting physiological responses of individual neurons. Historically, generation of three-dimensional (3D) neuronal reconstructions together with comprehensive mapping of synaptic inputs has been an extensive task requiring manual identification of putative synaptic contacts directly from tissue samples or digital images. Recent developments in neuronal tracing software applications have improved the speed and accuracy of 3D reconstructions, but localization of synaptic sites through the use of pre- and/or post-synaptic markers has remained largely a manual process. To address this, we developed an algorithm, based on 3D distance measurements between putative pre-synaptic terminals and the post-synaptic dendrite. The algorithm is implemented with custom Matlab routines, and its effectiveness evaluated through analysis of primary sensory afferent terminals on motor neurons.

Committee:

David Ladle, PhD (Committee Chair); Mark Rich, MD,PhD (Committee Member); Christopher Wyatt, PhD (Committee Member)

Subjects:

Anatomy and Physiology; Biology; Biomedical Engineering; Biomedical Research; Computer Science; Medical Imaging; Neurobiology; Neurology; Neurosciences; Physiology; Scientific Imaging

Keywords:

Confocal microscopy; Synapse localization; Dendrite; Tracing; Image analysis; Matlab; Skeleton

Wang, FangjingBiomedical Imaging of Stem Cells Using Reporter Genes
Doctor of Philosophy, Case Western Reserve University, 2010, Biomedical Engineering

Mesenchymal stem cells (MSCs), derived from nearly all adult organs, can differentiate into multiple lineages including osteoblasts, chondrocytes and adipocytes under different local micro-environments for tissue repair. MSCs have also shown to ameliorate graft versus host disease (GVHD) caused by allogeneic hematopoietic stem cell transplantation, via suppressing the activation and proliferation of the alloreactive lymphocytes. Therefore, MSCs have great potential in bone tissue regeneration and stem cell-based therapies. However, previous techniques to track stem cells in vivo are usually associated with frequent animal sacrifice followed by subsequent histology analysis or RT-PCR verification. A continuous, non-invasive, real time and longitudinal imaging technique is lacking.

In this study, we aimed to establish such a platform technology to image stem cell biodistribution in a disease model (GVHD) in vivo. A triple-reporter gene containing luc-mrfp–ttk was incorporated into hMSCs via lentiviral transduction. The gene of luc was imaged with BLI and ttk imaged with PET. The proliferation rate of the transduced stem cells was reduced compared to the wild type cells although the stem cell differentiation potential was reserved. The transcriptional changes between transduced and wild-type stem cells were examined via gene microarrays to identify the key genes related to proliferation and mesenchymal differentiation to determine the transduction effect. Stem cells that were loaded into ceramic cubes and implanted into NOD/SCID mice s.c. were longitudinally imaged in vivo by BLI for more than 3 months. PET was also capable of imaging the implanted stem cells in the ceramic cubes. Histology studies confirmed the formation of bone from the transduced hMSCs in vivo. These indicate that the imaging template was successfully developed.

In an animal model of GVHD developed in mice, hMSCs were injected intravenously for the treatment of this disease. It was shown that hMSCs enhanced the survival of the GVHD mice compared to the untreated mice. BLI results showed primary entrapment of hMSCs in lung, while only a small fraction of cells transiently migrated to the intestine. Cells in the mice were undetectable 7 days after their transplantation. Although arterial injection led to enhanced cell distribution into different organs such as intestines, and prolonged hMSC retention in allogeneic mice, no efficacy was observed compared with the control group possibly due to the injury associated with the surgery procedure that allowed arterial injection. These data suggest that timely cell injection and repeated injection may be necessary to effectively prevent or alleviate this disease.

In summary, this imaging technology plays an important role in tracking stem cells, in revealing disease development mechanisms, as well as in optimizing stem cell treatment strategy.

Committee:

Gerald Saidel (Committee Chair); Zhenghong Lee (Advisor); James Dennis (Committee Member); Horst von Recum (Committee Member); Kevin Bunting (Committee Member)

Subjects:

Biomedical Research; Engineering; Scientific Imaging

Keywords:

Imaging; BLI; PET; GVHD; mesenchymal stem cells; reporter gene; non-invasive; repeated

Rybaczyk, Leszek A.Comparative Gene Expression Analysis To Identify Common Factors In Multiple Cancers
Doctor of Philosophy, The Ohio State University, 2008, Integrated Biomedical Sciences
Most current cancer research is focused on tissue-specific genetic mutations. Familial inheritance (e.g., APC in colon cancer), genetic mutation (e.g., p53), and overexpression of growth receptors (e.g., Her2-neu in breast cancer) can potentially lead to aberrant replication of a cell. Studies of these changes provide tremendous information about tissue-specific effects but are less informative about common changes that occur in multiple tissues. The similarity in the behavior of cancers from different organ systems and species suggests that a pervasive mechanism drives carcinogenesis, regardless of the specific tissue or species. In order to detect this mechanism, I applied three tiers of analysis at different levels: hypothesis testing on individual pathways to identify significant expression changes within each dataset, intersection of results between different datasets to find common themes across experiments, and Pearson correlations between individual genes to identify correlated genes within each dataset. By comparing a variety of cancers from different tissues and species, I was able to separate tissue and species specific effects from cancer specific effects. I found that downregulation of Monoamine Oxidase A is an indicator of this pervasive mechanism and can potentially be used to detect pathways and functions related to the initiation, promotion, and progression of cancer.

Committee:

Kun Huang, PhD (Advisor); Jeffery Kuret, PhD (Committee Member); Daniel Janies, PhD (Committee Member); Randy Nelson, PhD (Other)

Subjects:

Biochemistry; Bioinformatics; Biology; Biomedical Research; Biostatistics; Cellular Biology; Epidemiology; Gender; Genetics; Gerontology; Gynecology; Health; Immunology; Mathematics; Molecular Biology; Oncology; Pharmaceuticals; Pharmacology; Scientific Imaging; Statistics

Keywords:

Monoamine; cancer; indicator of cancer; multiple cancers; microarray; multiple datasets; cross platform; biomarker

Montello, Aaron DavidAn Experimental Investigation of Water Droplet Growth, Deformation Dynamics and Detachment in a Non-Reacting PEM Fuel Cell via Fluorescence Photometry
Master of Science, The Ohio State University, 2008, Mechanical Engineering

While the concept of fuel cells has been around for more than 100 years, they have long been considered too expensive and not well refined enough for mainstream application. With the combined pressures of decreasing world oil supplies as well as growing concerns for the role carbon dioxide emissions are playing to cause climate change, PEM fuel cell technology has reemerged as a potential power source for automotive transportation. Thanks to significant advances in material technologies, fuel cell system costs have reduced while performance has significantly increased. There still exist various cost issues, as well as a wide variety of technical barriers preventing broad based adoption of the technology. One of these key technical barriers is low system power density, due in part to a restriction of the rate that fuel can be forced through the system. This restriction is a result of the limitation in the rate of removal of product water from the system.

It has been well documented that water production in fuel cells occurs in discrete locations, resulting in the formation and growth of discrete droplets within the gas flow channels (GFCs) along the gas diffusion layer (GDL) surface. There have been few experimental efforts aimed at understanding the dynamic interaction of such water droplets with the crossing air flow however. The first portion of this research uses a simulated fuel cell GFC with three transparent walls in conjunction with a high speed fluorescence photometry system to capture videos of dynamically deforming droplets. In viewing such videos it is noted that the droplets undergo vibratory deformation patterns. The video information is then processed and analyzed in Matlab, resulting in the formulation of plots indicating the dominant horizontal and vertical deformation frequency components over the range of sizes of droplets from formation to detachment. The system is also used to characterize droplet detachment size at a variety of channel air velocities.

There have been a fair number of experimental research efforts attempting to aid in the water removal process, however it is believed that more effective, simpler solutions exist than those that have been tried. Using a solenoid valve fixed near the channel air exit, it is possible to introduce a small amount of pulsed air flow in addition to the predominant unidirectional flow. A wide range of solenoid excitation frequencies are tested for one of the flow velocities analyzed in the first portion of the work, and it is found that certain excitation conditions allow for critical droplet size reductions of greater than 20%. It is believed that this behavior should correspond with improved water efflux characteristics and this technique is believed to have promise for future fuel cell operational improvement.

Committee:

Yann Guezennec, PhD (Advisor); Giorgio Rizzoni, PhD (Committee Member); Junmin Wang, PhD (Committee Member)

Subjects:

Automotive Materials; Chemical Engineering; Engineering; Experiments; Fluid Dynamics; Hydrology; Mechanical Engineering; Optics; Scientific Imaging; Transportation

Keywords:

PEM fuel cell; experimental; water management; water droplet dynamics; GDL; GFC; variable air flow; two-phase flow; visualization; fluorescence photometry; video processing

Kintz, Andrew LaneNullspace MUSIC and Improved Radio Frequency Emitter Geolocation from a Mobile Antenna Array
Doctor of Philosophy, The Ohio State University, 2016, Electrical and Computer Engineering
This work advances state-of-the-art Radio Frequency (RF) emitter geolocation from an airborne or spaceborne antenna array. With an antenna array, geolocation is based on Direction of Arrival (DOA) estimation algorithms such as MUSIC. The MUSIC algorithm applies to arbitrary arrays of polarization sensitive antennas and yields high resolution. However, MUSIC fails to obtain its theoretical resolution for simultaneous, closely spaced, co-frequency signals. We propose the novel Nullspace MUSIC algorithm, which outperforms MUSIC and its existing modifications while maintaining MUSIC's fundamental orthogonality test. Nullspace MUSIC applies a divide-and-conquer approach and estimates a single DOA at a time. Additionally, an antenna array on an aircraft cannot be perfectly calibrated. RF waves are blocked, reflected, and scattered in a time-varying fashion by the platform around the antenna array. Consequently, full-wave electromagnetics simulations or demanding measurements of the entire platform cannot eliminate the mismatch between the true, in-situ antenna patterns and the antenna patterns that are available for DOA estimation (the antenna array manifold). Platform-induced manifold mismatch severely degrades MUSIC's resolution and accuracy. We show that Nullspace MUSIC improves DOA accuracy for well separated signals that are incident on an airborne antenna array. Conventionally, geolocation from a mobile platform draws Lines of Bearing (LOB) from the antenna array along the DOAs to find the locations where the DOAs intersect with the ground. However, averaging the LOBs in the global coordinate system yields large errors due to geometric dilution of precision. Since averaging positions fails, a single emitter is typically located by finding the position on the ground that yields the Minimum Apparent Angular Error (MAAE) for the DOA estimates over a flight. We extend the MAAE approach to cluster LOBs from multiple emitters. MAAE clustering geolocates multiple simultaneous and co-frequency emitters in spite of highly erratic DOA estimates. We also mitigate manifold mismatch by applying the Direct Mapping Method (DMM). DMM averages DOA spectra on the earth's surface and estimates the emitter locations directly from the composite spectrum. In the example results presented, our goal is to geolocate four diversely polarized emitters with a seven-element antenna array. This is too challenging for MAAE and DMM. We fuse Nullspace MUSIC and DMM into the novel Nullspace DMM algorithm and demonstrate that Nullspace DMM locates all emitters. Finally, we apply the proposed geolocation algorithms to real-world experimental data. A six-element antenna array and Data Collection System (DCS) were installed on a small aircraft. The DCS recorded signals from four live transmitters during a three-hour flight over Columbus, Ohio. The four emitters were geolocated from various segments of the flight. As expected, individual DOA estimates were erratic and widespread due to the airplane's perturbations of the measured array manifold. MAAE and DMM locate at most three of the four emitters. On the other hand, Nullspace DMM yields unambiguous estimates for every emitter in every flight segment. The successful experimental trials show that Nullspace DMM could significantly enhance airborne emitter geolocation in missions such as RF spectrum enforcement, locating unknown transmitters for defense, and search and rescue operations.

Committee:

Inder Gupta (Advisor); Joel Johnson (Committee Member); Fernando Teixeira (Committee Member); Can Koksal (Committee Member)

Subjects:

Aerospace Engineering; Applied Mathematics; Computer Engineering; Computer Science; Electrical Engineering; Electromagnetics; Electromagnetism; Engineering; Experiments; Mathematics; Music; Remote Sensing; Scientific Imaging; Systems Design

Keywords:

Radio Frequency Emitter Geolocation; Direction of Arrival Estimation; Antenna Array Signal Processing; Antenna Array Manifold Mismatch; Nullspace MUSIC; Polarization; Direct Mapping Method DMM; Nullspace DMM; Flight Experiment; Beamforming; Nullsteering;

SMITH, DENISE ANNE BUSHIn vitro Characterization of Echogenic Liposomes (ELIP) for Ultrasonic Delivery of Recombinant Tissue-type Plasminogen Activator (rt-PA)
PhD, University of Cincinnati, 2008, Engineering : Biomedical Engineering
Ultrasound contrast agents (UCAs) stabilized against gas diffusion in the bloodstream yet triggered for destruction by specially designed pulses of ultrasound are desirable for clinical applications in vivo. Echogenic liposomes (ELIP) are nano-sized phospholipid vesicles that contain both gas and fluid. With incorporation of a drug, such as recombinant tissue-Plasminogen Activator (rt-PA), these liposomes may be able to deliver a high local concentration of rt-PA by site-specific delivery of the drug directly to thrombi, with a lower systemic dose overall. Therefore, it is necessary to assess ELIP stability and destruction thresholds in vitro before their application in clinical diagnostic imaging and targeted drug delivery. Several researchers have used optical and acoustic techniques to identify three dominant mechanisms of UCA destruction; static diffusion, acoustically driven diffusion, and fragmentation (Chomas et al, 2001a; Bouakaz et al., 2005; Porter et al., 2006). We have developed new acoustic techniques to assess these three destruction thresholds of an FDA-approved UCA, Optison®, and unmodified ELIP utilizing a clinical diagnostic ultrasound scanner (Porter et al., 2006; Smith et al., 2007a). Recently, in vitro studies were performed with an innovative drug-encapsulated contrast agent, rt-PA-loaded ELIP. Their stability during contrast imaging was assessed using low output B-mode pulses and rt-PA was found to remain associated with the lipid bilayer. They were also fragmented using color Doppler pulses for determination of drug delivery by spectrophotometrically measuring the concentration of rt-PA released (Smith et al., 2007b). The primary objective of this dissertation was to characterize a novel echogenic lipid-based drug-encapsulated UCA using a diagnostic ultrasound scanner for its potential use in both image-guided and ultrasound-triggered drug delivery.

Committee:

Christy K. Holland, PhD (Committee Chair); William S. Ball, MD (Committee Member); George J. Shaw, MD, PhD (Committee Member); T. Douglas Mast, PhD (Committee Member)

Subjects:

Acoustics; Biomedical Research; Engineering; Health; Pharmaceuticals; Physics; Radiology; Scientific Imaging

Keywords:

echogenic liposomes; ultrasound; diagnostic ultrasound; Optison; contrast agents; ultrasound-enhanced thrombolysis; rt-PA; drug delivery; drug release; destruction threshold; static diffusion; acoustically driven diffusion; rapid fragmentation

Narayan, ChayaPolarimetric Stokes Imaging for the Detection of Tumor Margins and Segmentation
Master of Science in Engineering, University of Akron, 2013, Electrical Engineering
Cancer is the second most common cause of death in the US and is responsible for about 25% of the deaths according to the American Cancer Society. There is a need for quick and accurate detection of tumors in a real time automated environment without the delays associated with laboratory procedures. There is also a need to identify the exact location and extent of the tumor tissues so that surgeries would not only be more effective but also as minimally invasive as possible. The purpose of this study was to distinguish the margins between healthy and cancerous tissues on slides containing samples of mice brain tumor through the use of polarimetric stokes imaging techniques. Comparison between the cancerous and healthy tissue portions from polarimetric imaging was expected to provide better distinction of the two areas and the margin between them. The experiments were conducted with a broadband white light source and the data was recorded using a circular polarized rotating retarder system in transmission mode. The samples used were unstained sliced sections of mice brain prepared using standard procedures. The images were saved with an optical camera that was impartial to color or fluorescence properties of the samples. The Stokes parameter images of the samples were computed through the Fourier analysis method. The images for Degree of Polarization (DOP), Degree of Linear Polarization (DOLP) and Degree of Circular Polarization (DOCP) were also computed. The images thus generated were segmented and post-processed to analyze properties such as texture and tissue density. Additionally, small selections of tumor and healthy tissue having the same pixel area were chosen from the Stokes images for further statistical analyses. The statistical findings from this study showed that image features of tumor tissue had lower variance values to the various degrees of polarization when compared to that of normal tissue. This meant that the surface of tumors were more densely packed and more uniform than healthy tissue thus enabling successful segmentation, thereby proving the expectation that polarimetric stokes imaging was an efficient and robust tool in the detection of margins.

Committee:

George C. Giakos, Dr. (Advisor); Kye-Shin Lee, Dr. (Committee Member); H. L. Arjuna Madanayake, Dr. (Committee Member)

Subjects:

Biology; Biomedical Engineering; Biomedical Research; Electrical Engineering; Engineering; Experiments; Health; Health Care; Health Sciences; Optics; Pathology; Scientific Imaging; Technology

Keywords:

Polarimetry, Stokes Imaging, Cancer margins, Segmentation, Polarimetric Imaging

Next Page