Dissertations / Theses on the topic 'Technologies of diagnostic imaging'
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Farah, Yasser Abdulhamid Elskay, and L. O. Averyanova. "Technologies for prevention liver cancer in Egypt." Thesis, ХНУРЕ, 2019. http://openarchive.nure.ua/handle/document/8373.
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Deaths from liver cancer are common, especially in East Asia and Pacific, South Asia, and parts of Sub-Saharan Africa, largely as a result of infection decades ago. Controlling the risk factors would not only reduce the incidence of liver cancer; it would also reduce the incidence of cirrhosis and its other complications. This paper will discuss the clinical implications of imaging in screening, diagnosis, staging, and follow-up of patients in liver malignancies.
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Bryan, Stirling. "The economic evaluation of diagnostic imaging technologies : an investigation of the use of conjoint measurement." Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310057.
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Fang, Xiaochao. "Design and integration of a low-noise readout chain in CMOS technology for APD-based sall-animal PET imaging." Strasbourg, 2011. http://www.theses.fr/2011STRA6021.
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Cette thèse présente mon travail de recherche sur la conception d'une chaîne de lecture dédiée à la TEP (Tomographie à Emission de Positons) fondée sur l'APD (Avalanche Photo Diode) pour les petits animaux. Le laboratoire IPHC (Institut Pluridisciplinaire Hubert Curien, UMR 7178) est en train de développer un système d'imagerie multimodale dénommé AMISSA (A Multimodality Imaging System for Small Animal) dédié au petit animal. L'AMISSA est composé par un micro imageur TDMX (micro TomoDensitoMétrie X), un micro imageur TEMP (Tomographie d'Emission Mono Photonique) et un micro imageur TEP. Le TDMX et le TEMP ont été réalisés. L'imagerie TEP permettra d'ajouter la modalité manquante au banc d'imagerie. Deux prototypes ont été développés afin de réaliser la chaîne de lecture complète dédiée à l'APD. Le premier prototype APD Chip est un circuit bas bruit de dix voies. Chaque voie est constituée d'un CSA (Charge Sensitive Amplifier), d'un CR-(RC)2 « shaper » et d'un « buffer » analogique. Le test montre que l'ENC (Equivalent Noise Charge) à l'entrée est égal à 275 ± 2 e- + 10 e-/pF pour un « shaping time » de 136 ns. Le deuxième prototype PETROC est un microcircuit mixte qui comprend un PDH (Peak Detect and Hold) d'huit voies et un TDC (Time-to-Digital Converter) de cinq voies. L'erreur sur le pic détecté est inférieure à 0. 7%. Une interpolation multi-niveaux est incluse dan la conception du TDC afin d'obtenir une plage de mesure de 10 µs et un pas de 20 ps. Dans ce texte, des analyses théoriques et des prototypes sont présentés, ainsi que la conception des circuits. Les résultats des tests du premier prototype sont également exposésThis thesis presents my research work on the conception of a readout chain dedicated to the APD (Avalanche Photo Diodes)-based PET (Positron Emission Tomography) imaging for small animal. The PET imaging allows the conjunction of its modality with the micro CT (X-ray Computerized Tomography) and micro SPECT (Single Photon Emission Computed Tomography) imaging which have been developed at IPHC (Institut Pluridisciplinaire Hubert Curien, UMR 7178). These three imaging compose a multi-modality imaging system for small animal (AMISSA). Two prototypes have been designed in order to finally realize the complete readout chain. The first one (called APD Chip) is a ten-channel low noise front-end circuit. Every channel consists of a Charge Sensible Amplifier (CSA), a CR-(RC)2 shaper, and an analogue buffer. The Equivalent Noise Charge (ENC) in input from test is equal to 275 ± 2 e- + 10 e- /pF for a shaping time of 136 ns. The second prototype PETROC is a mixed circuit. It comprises an eight-channel Peak Detect and Hold (PDH) circuit and a five-channel Time-to-Digital Converter (TDC). The simulation shows that the error is less than 0. 7% over the whole dynamic range. A multi-level interpolation was implemented in the TDC design to obtain a measurement range up to 10 µs and a bin size of 20 ps. In this thesis, the prototypes are presented for both their theoretical analyses and their circuit designs. The test results of the first prototype are also presented
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Dhillon, Ravinder. "Diagnostic imaging pathways." University of Western Australia. School of Medicine and Pharmacology, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0126.
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[Truncated abstract] Hypothesis: There is deficiency in the evidence base and scientific underpinning of existing diagnostic imaging pathways (DIP) for diagnostic endpoints. Objective: a) To carry out systematic review of literature in relation to use of diagnostic imaging tests for diagnosis and investigation of 78 common clinical problems, b) To identify deficiencies and controversies in existing diagnostic imaging pathways, and to develop a new set of consensus based pathways for diagnostic imaging (DIP) supported by evidence as an education and decision support tool for hospital based doctors and general practitioners, c) To carry out a trial dissemination, implementation and evaluation of DIP. Methods: 78 common clinical presentations were chosen for development of DIP. For general practitioners, clinical topics were selected based on the following criteria: common clinical problem, complex in regards to options available for imaging, subject to inappropriate imaging resulting in unnecessary expenditure and /or radiation exposure, and new options for imaging of which general practitioners may not be aware. For hospital based junior doctors and medical students, additional criteria included: acute presentation when immediate access to expert radiological opinion may be lacking and clinical problem for which there is a need for education. Systematic review of the literature in relation to each of the 78 topics was carried out using Ovid, Pubmed and Cochrane Database of Systematic Reviews. ... The electronic environment and the method of delivery provided a satisfactory medium for dissemination. Getting DIP implemented required vigorous effort. Knowledge of diagnostic imaging and requesting behaviour tended to become more aligned with DIP following a period of intensive marketing. Conclusions: Systematic review of literature and input and feedback from various clinicians and radiologists led to the development of 78 consensus based Diagnostic Imaging Pathways supported by evidence. These pathways are a valuable decision support tool and are a definite step towards incorporating evidence based medicine in patient management. The clinical and academic content of DIP is of practical use to a wide range of clinicians in hospital and general practice settings. It is source of high level knowledge; a reference tool for the latest available and most effective imaging test for a particular clinical problem. In addition, it is an educational tool for medical students, junior doctors, medical imaging technologists, and allied health care personnel.
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Dhillon, Ravinder. "Diagnostic imaging pathways /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0126.
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Rijn, Jeroen Christoffel van. "Multidimensionality in diagnostic imaging." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2006. http://dare.uva.nl/document/89940.
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OLDEN, JULIE, Pete Nielsen, Nicole Schechter, and Patrick Ackerman. "IMAGING DIAGNOSTIC LABORATORIES: BUSINESS PLAN." Thesis, The University of Arizona, 2008. http://hdl.handle.net/10150/190714.
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Trill, Helen. "Diagnostic technologies for wound monitoring." Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/1107.
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Chronic wound infections represent a worldwide problem, generating high morbidity and medical expense. Failure to control infections such as MRSA in the reparative process of a wound can cause disruption of normal anatomical structure and function, resulting in a chronic wound. Existing approaches to identifying infection largely involve surveying a range of physical parameters, and a limited use of non-invasive technologies. Evaluation is
time consuming, and often results in inconsistencies in patient care.
This project researches three possible alternative methodologies/technologies for the monitoring of wounds, by measuring components of wound fluid. Two of the three
technologies are designed to be used by physicians and patients, similarly to commercially available home blood glucose test kits, and are based on the measurement of three biomarkers: glucose, ethanol and H2O2 in PBS, and in serum as surrogate wound fluid. The first is a voltammetric technique known as dual pulse staircase voltametry (DPSV), which produces peaks characteristic of particular analytes at an electrode. The second is an amperometric biosensor array, based on screen printed three electrode assembies of carbon, rhodinised carbon (glucose biosensor only) and Ag/AgCl reference. The glucose biosensor uses glucose oxidase enzyme as the biorecognition agent, the H2O2 biosensor is a mediated system using horseradish peroxidase enzyme and dimethylferrocene mediator, and the ethanol biosensor is a bienzyme mediated system utilising alcohol oxidase enzyme
horseradish peroxidase enzyme and coupled dimethylferrocene mediator. Wounds are
known to produce characteristic odours, therefore the third technology studied is a single sensor odour analyser with advanced data analysis to detect five commonly occuring wound bacteria, S.aureus, K.pneumoniae, S.pyogenes, E.coli and P.aeruginosa in growth media and surrogate wound fluid. This technology would be used as a 'near patient' monitoring system and is based on machine olfaction similar to that of a commercial electronic nose, but uses a single metal oxide sensor in combination with principle components analysis.
DPSV scans of the individual analytes demonstrated distinctive peaks, exhibiting nonlinear relationships with concentration. A great deal of useful information was generated using this technique, however, limitations were discovered regarding repeatability and inter-analyte interference in mixtures. Limits of detection in surrogate wound fluid with the glucose biosensor, hydrogen peroxide biosensor, and ethanol biosensor were as follows:
169.5 µM glucose, 8.43 µM hydrogen peroxide, and 7.94 µM ethanol respectively (all at
99.7% confidence). Direct detection of ethanol from metabolically active S.aureus in
surrogate wound fluid yielded a limit of detection of 1.23 x 108 CFU/ml at 99.7%
confidence, and 19 µM in terms of ethanol specific response. The single sensor odour
analyser demonstrated the ability to detect and discriminate between the three biomarkers, between five bacteria individually, and partial discrimination of paired bacteria (in broth and surrogate wound fluid). It was also found that S.aureus could be detected down to a
cell density of 5x106CFU/ml in surrogate wound fluid, lower than that found for the
biosensor concept.
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Hammadi, Shumoos T. H. "Novel medical imaging technologies for processing epithelium and endothelium layers in corneal confocal images. Developing automated segmentation and quantification algorithms for processing sub-basal epithelium nerves and endothelial cells for early diagnosis of diabetic neuropathy in corneal confocal microscope images." Thesis, University of Bradford, 2018. http://hdl.handle.net/10454/16924.
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Diabetic Peripheral Neuropathy (DPN) is one of the most common types of diabetes that can affect the cornea. An accurate analysis of the corneal epithelium nerve structures and the corneal endothelial cell can assist early diagnosis of this disease and other corneal diseases, which can lead to visual impairment and then to blindness. In this thesis, fully-automated segmentation and quantification algorithms for processing and analysing sub-basal epithelium nerves and endothelial cells are proposed for early diagnosis of diabetic neuropathy in Corneal Confocal Microscopy (CCM) images. Firstly, a fully automatic nerve segmentation system for corneal confocal microscope images is proposed. The performance of the proposed system is evaluated against manually traced images with an execution time of the prototype is 13 seconds. Secondly, an automatic corneal nerve registration system is proposed. The main aim of this system is to produce a new informative corneal image that contains structural and functional information. Thirdly, an automated real-time system, termed the Corneal Endothelium Analysis System (CEAS) is developed and applied for the segmentation of endothelial cells in images of human cornea obtained by In Vivo CCM. The performance of the proposed CEAS system was tested against manually traced images with an execution time of only 6 seconds per image. Finally, the results obtained from all the proposed approaches have been evaluated and validated by an expert advisory board from two institutes, they are the Division of Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar and the Manchester Royal Eye Hospital, Centre for Endocrinology and Diabetes, UK.
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Bennett, Dr Alexander. ""Diagnostic and Prognostic Imaging in Spondyloarthropathy"." Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534424.
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Egbe, Nneoyi Onen. "Measurement of dose in diagnostic radiology and the effect of dose reduction on image quality." Thesis, Available from the University of Aberdeen Library and Historic Collections Digital Resources. Online version available for University members only until March, 23, 2010, 2008. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=25469.
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Basoglu, Chris. "A generalized programmable system and efficient algorithms for ultrasound backend processing /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/5978.
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Price, R. "Developing practice in radiography and diagnostic imaging." Thesis, University of Hertfordshire, 2007. http://hdl.handle.net/2299/1056.
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An increase in the range and capability of imaging modalities has resulted in greater demands for radiology services. This research investigates how these changes have affected role requirements and role extensions of radiographers and the consequent implications for the educational needs of radiographers. Semi-structured interviews and three successive surveys of NHS radiography managers showed that the adoption and diffusion of extended roles in radiography had increased significantly over a ten year period. Role changes included additions both to the procedures carried out by radiographers, and to the reporting of procedures, e.g. film reporting, once the domain of radiologists, is now undertaken by radiographers in many trusts. Imaging managers’ views on the factors that encouraged or deterred the introduction of extended roles were explored. While many radiographers were keen to adopt new roles, implementation was unlikely without radiological support. Respondents believed the proposed ‘four-tier structure’ would help overcome staffing difficulties, while providing an improved career framework to advance the professional status of radiographers. A key theme was the need for greater clinical knowledge to facilitate transition to advanced practice. Three studies investigated radiography education. The first used a survey to investigate the preparedness for practice of three cohorts of newly qualified radiographers. Graduates recognised the importance of continuing professional development with extended role skills identified as a priority. The second study examined the relationship between contemporary practice and UK undergraduate radiography curricula. Most programmes had responded positively to developing technology. The third study used a survey to investigate the training for extended roles provided by employers. While most provided some training, much was unaccredited, and there was considerable variation in the duration of training for similar roles. The research has documented developments taking place at a time of enormous technological innovation. It provides key data on the changing practice of radiography that will be useful to all stakeholders planning improvements to radiography services. The data lead to a re-definition of practice and recommendations for supporting education and training.
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Juntunen, M. (Mikael). "Diagnostic and quantitative imaging of knee osteoarthritis." Bachelor's thesis, University of Oulu, 2016. http://urn.fi/URN:NBN:fi:oulu-201606302589.
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Articular cartilage is a connective tissue, that provides virtually frictionless articulation between bones in a joint. Degenerative joint disease, osteoarthritis (OA), is the most common type of arthritis. During its development, cartilage is progressively lost, decreasing the functional capacity of the joint. Currently it is diagnosed with radiography, which might not show changes in cartilage tissue during the early stages of OA. In radiography, cartilage degeneration might be visible only when OA has progressed to advanced stage. The lack of effective treatment methods for advanced stage of OA has generated interest towards the development of biomarkers for the detection of early OA. Magnetic resonance imaging (MRI), especially relaxation time mapping, is able to provide accurate information on early changes in cartilage structure and is considered to be one of the best candidates for the detection of early OA. Morphological assessment of three-dimensional MRI, on the other hand, can be used as an indicator of the rate of cartilage loss. In this work, OA is reviewed and the current methods for diagnosing OA are studied. Relaxation time mapping and morphological assessment of articular cartilage are current research interests and these methods will also be discussed.
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Agustsson, Hilmir. "Diagnostic Musculoskeletal Imaging: How Physical Therapists Utilize Imaging in Clinical Decision-Making." Diss., NSUWorks, 2018. https://nsuworks.nova.edu/hpd_pt_stuetd/72.
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This qualitative study describes how physical therapist experts in musculoskeletal disorders evaluate and interpret imaging studies and how they employ imaging in clinical decision-making. The informants are physical therapists who are certified orthopedic clinical specialists (OCS) and/or fellows of the American Academy of Orthopaedic Manual Physical Therapists (AAOMPT). The study employed web conferencing to display patient cases, record screen-capture videos, and to conduct interviews. Informants were observed and their activity video-captured as they evaluated imaging studies and, afterwards, interviews were employed to explore the processes they utilized to evaluate and interpret the images and to discuss imaging-related clinical decision-making, including possible functional consequences of changes seen in the images, contraindications to treatment, and indications for referral. The interviews were transcribed and analyzed in the tradition of grounded theory. This study found that the informants’ evaluation of imaging studies was contextual and non-systematic, guided by the clinical presentation. The informants used imaging studies to provide a deeper understanding of clinical findings and widen perspectives, arriving at clinical decisions through the synthesis of imaging, clinical findings, and didactic knowledge. They tended to look for imaging evidence of interference with normal motion, rather than evidence of pathology. Overall, the informants expressed conservative views on the use of imaging, noting they would rather use clinical findings and treatment response than imaging findings as a basis for referral to other health care professionals. Using imaging studies to support clinical decision-making can provide physical therapists a wider perspective when planning treatment interventions. By showing physical therapists’ approach to interpreting imaging studies and how this relates to their clinical decision-making, the findings of this study could contribute to discussions of the place of imaging in physical therapist practice, as well as help set objectives for imaging curricula in professional-level and continuing education.
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Li, Jia, and 李佳. "Computational imaging technologies for optical lithography extension." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206757.
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With the development and production of integrated circuits at the 22nm node, optical lithography faces increasing challenges to keep up with the specifications on its performance along various metrics, such as pattern fidelity and process window. The past few years saw the emergence of source mask optimization (SMO) as an important technique in computational lithography, which allows lithographers to rise to the challenges by exploiting a larger design space on both mask and illumination configuration, and integrates with methods such as inverse imaging. Yet, many methods that are used to tackle SMO problem arising in the inverse imaging involve heavy computation and slow convergence, making the technique unappealing for full-chip simulations or large circuits. Therefore, the purpose of this research is to take advantage of computational imaging technologies to solve source and mask design problems, extending the lifetime of optical lithography.
The computational burden results in part from identical optimization over the whole mask pattern, consequently, we propose a weighted SMO scheme which applies different degrees of correction in the corresponding regions so that the optimal solutions are reached with fewer iterations. Additionally, undesirably long time is also attributed to the algorithm adopted to solve SMO problem. A fast algorithm based on augmented Lagrangian methods is therefore developed, which use the quasi-Newton method to accelerate convergence, thereby shortening the overall execution time. However, as semiconductor lithography is pushed to even smaller dimensions, mask topography effects have to be taken into account for a more accurate solution of SMO. At this stage, intensive computation is spent mainly in rigorous 3D mask modeling and simulations. To address this issue, we devise an optimization framework incorporating pupil aberrations into SMO procedure, which is performed based on the thin mask model so as to ensure a faster speed.
We apply the above approaches to various mask geometries with different critical dimensions. Compared to conventional SMO, simulation results show that the proposed methods lead to better pattern fidelity and larger process window, especially in rigorous calculations. This demonstrates that the source and mask design generated through our algorithms are more practical. More importantly, the improved performance is not at the cost of speed. Instead, our methods take the least time to achieve it. This allows the advantages of computational imaging technologies to be worth exploring for further applications in optical lithography.published_or_final_version
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
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Bruwer, Mark-John MacGregor John Frederick. "Process systems approaches to diagnostic imaging and identification." *McMaster only, 2006.
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Dumbarton, Carolyn. "Infection control practices within the Diagnostic Imaging Department." Thesis, Bangor University, 2007. https://research.bangor.ac.uk/portal/en/theses/infection-control-practices-within-the-diagnostic-imaging-department(162b6def-6638-4bd6-9dce-31069248c31c).html.
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This study investigated radiographers' infection control practice within the Diagnostic Imaging Department. The investigation was carried out in three phases. Structured observations were carried out in four hospitals to determine the frequency and identify the situations in which infection control procedures were performed. Bacterial analysis was performed on equipment in one hospital to identify levels of contamination associated with the lack of cleaning witnessed during the observational study. Finally Focus Group discussions were used in two hospitals to establish the opinions and attitudes of radiographers regarding infection control, and to identify factors that prevented as well as those that facilitated these practices. Radiographers' compliance with infection control practice was low. Hand decontamination prior to patient contact was observed on only (n=34) 4% of occasions, and afterwards on (n=145) 17% of occasions. Infection control practice was frequently inappropriate when radiographers were dealing with situations involving immunosuppressed patients, those with open wounds, and in the handling of needles. Equipment was cleaned on only (n=30) 4% of occasions. It was found that 56% of the pieces of equipment were found to have unacceptable levels of bacterial contamination. However, after simple decontamination the measure of bacterial load was significantly reduced. The Focus Group discussions indicated that radiographers had good levels of knowledge regarding infection control, but issues such as lack of time and resources, low perceived risk of infection and the culture of the departments and NHS trusts had a negative effect on compliance rates. For maximum compliance it is thought that a multifaceted intervention should be implemented. The researcher believes the use of Quality Circles would develop a culture that would encourage compliance with infection control protocols. Better compliance with infection control protocols achieved through changes in education, procedures and culture in the Diagnostic Imaging Department are, therefore, vital to protect both patients and staff.
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Thomas, Kristine A. "Image Processing as Applied to Medical Diagnostics." Thesis, University of Oregon, 2010. http://hdl.handle.net/1794/10724.
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xi, 56 p. : ill. (some col.) A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.Image processing is a powerful tool for increasing the reliability and reproducibility of disease diagnostics. In the hands of pathologists, image processing provides quantitative data from histological images which supplement the qualitative data currently used by specialists. This thesis presents a novel method for analyzing digitized images of hematoxylin and eosin (H&E) stained histology slides to detect and quantify inflammatory polymorphonuclear leukocytes to aid in the grading of acute inflammation of the placenta as an example of the use of image processing in aid of diagnostics. Methods presented in this thesis include segmentation, a novel threshold selection technique and shape analysis. The most significant contribution is the automated color threshold selection algorithm for H&E stained histology slides which is the only unsupervised method published to date.
Committee in charge: Dr. John Conery, Chair; Dr. Matthew J. Sottile
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Neumann, Markus. "Automatic multimodal real-time tracking for image plane alignment in interventional Magnetic Resonance Imaging." Phd thesis, Université de Strasbourg, 2014. http://tel.archives-ouvertes.fr/tel-01038023.
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Interventional magnetic resonance imaging (MRI) aims at performing minimally invasive percutaneous interventions, such as tumor ablations and biopsies, under MRI guidance. During such interventions, the acquired MR image planes are typically aligned to the surgical instrument (needle) axis and to surrounding anatomical structures of interest in order to efficiently monitor the advancement in real-time of the instrument inside the patient's body. Object tracking inside the MRI is expected to facilitate and accelerate MR-guided interventions by allowing to automatically align the image planes to the surgical instrument. In this PhD thesis, an image-based workflow is proposed and refined for automatic image plane alignment. An automatic tracking workflow was developed, performing detection and tracking of a passive marker directly in clinical real-time images. This tracking workflow is designed for fully automated image plane alignment, with minimization of tracking-dedicated time. Its main drawback is its inherent dependence on the slow clinical MRI update rate. First, the addition of motion estimation and prediction with a Kalman filter was investigated and improved the workflow tracking performance. Second, a complementary optical sensor was used for multi-sensor tracking in order to decouple the tracking update rate from the MR image acquisition rate. Performance of the workflow was evaluated with both computer simulations and experiments using an MR compatible testbed. Results show a high robustness of the multi-sensor tracking approach for dynamic image plane alignment, due to the combination of the individual strengths of each sensor.
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Pereira, Raul Alexandre Marques. ""Reliability of diagnostic procedures in medical imaging: Narrow Band Imaging Endoscopy in gastric disease"." Dissertação, Faculdade de Medicina da Universidade do Porto, 2009. http://hdl.handle.net/10216/55712.
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Pereira, Raul Alexandre Marques. ""Reliability of diagnostic procedures in medical imaging: Narrow Band Imaging Endoscopy in gastric disease"." Master's thesis, Faculdade de Medicina da Universidade do Porto, 2009. http://hdl.handle.net/10216/55712.
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Syvertson, Tracey L. "Cost effectiveness analysis comparing two medical imaging technologies." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA302992.
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Thesis (M.S. in Management) Naval Postgraduate School, June 1995.Thesis advisor(s): William R. Gates, John Robert Barrios-Choplin. "June 1995." Bibliography: p. 51-52. Also available online. Mode of access: World Wide Web. System requirements: Adobe Acrobat Reader.
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Watts, Claire. "Metamaterials and their applications towards novel imaging technologies." Thesis, Boston College, 2015. http://hdl.handle.net/2345/bc-ir:104631.
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Thesis advisor: Willie J. PadillaThis thesis will describe the implementation of novel imaging applications with electromagnetic metamaterials. Metamaterials have proven to be host to a multitude of interesting physical phenomena and give rich insight electromagnetic theory. This thesis will explore not only the physical theory that give them their interesting electromagnetic properties, but also the many applications of metamaterials. There is a strong need for efficient, low cost imaging solutions, specifically in the longer wavelength regime. While this technology has often been at a standstill due to the lack of natural materials that can effectively operate at these wavelengths, metamaterials have revolutionized the creation of devices to fit these needs. Their scalability has allowed them to access regimes of the electromagnetic spectrum previously unobtainable with natural materials. Along with metamaterials, mathematical techniques can be utilized to make these imaging systems streamlined and effective. Chapter 1 gives a background not only to metamaterials, but also details several parts of general electromagnetic theory that are important for the understanding of metamaterial theory. Chapter 2 discusses one of the most ubiquitous types of metamaterials, the metamaterial absorber, examining not only its physical mechanism, but also its role in metamaterial devices. Chapter 3 gives a theoretical background of imaging at longer wavelengths, specifically single pixel imaging. Chapter 3 also discusses the theory of Compressive Sensing, a mathematical construct that has allowed sampling rates that can exceed the Nyquist Limit. Chapter 4 discusses work that utilizes photoexcitation of a semiconductor to modulate THz radiation. These physical methods were used to create a dynamic THz spatial light modulator and implemented in a single pixel imaging system in the THz regime. Chapter 5 examines active metamaterial modulation through depletion of carriers in a doped semiconductor via application of a bias voltage and its implementation into a similar single pixel imaging system. Additionally, novel techniques are used to access masks generally unobtainable by traditional single pixel imagers. Chapter 6 discusses a completely novel way to encode spatial masks in frequency, rather than time, to create a completely passive millimeter wave imager. Chapter 7 details the use of telecommunication techniques in a novel way to reduce image acquisition time and further streamline the THz single pixel imager. Finally, Chapter 8 will discuss some future outlooks and draw some conclusions from the work that has been done
Thesis (PhD) — Boston College, 2015
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics
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Chalker, S. L. "Magnetic nanoparticle and liposome technologies for multimodal imaging." Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1464424/.
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The overall aim was to produce a magnetolipopolyplex, a multimodal-imaging agent, for the detection of cancer. Iron oxide nanoparticles, which are used as negative contrast agents in magnetic resonance imaging were encapsulated into biocompatible liposomes alongside plasmid DNA and targeting peptides. The plasmid DNA provides the potential for optical imaging and PET through the inclusion of the red fluorescent protein reporter gene and the human sodium iodide symporter, which can be radiolabelled. The inclusion of targeting peptides in the formulation of the magnetolipopolyplexes allows for its site-specific delivery. Initially, poly(L)lysine (PLL) was bio-conjugated to the surface of commercially available iron oxide nanoparticles (MNPs) coated with dextran, rendering the surface charge of the MNPs positive and thus allowing for the electrostatic binding of negatively charged plasmid DNA (pDNA) to the surface. Two plasmids were produced; one coding for the red fluorescent protein (RFP gene) for optical imaging and the other with both RFP and the human sodium iodide symporter (hNIS) which can be radiolabelled for PET imaging. Once the pDNA was electrostatically bound to the PLL on the surface of the MNP, the functionalised MNP was encapsulated into a cationic liposome in order to produce a biocompatible means of delivering the liposome both in vivo and in vitro. Unfortunately, poor results were obtained for the in vitro transfections, which were attributed to their large size and negative surface charges. To overcome the issues faced by the formulation method and in vitro transfections studies, an alternative method of magnetolipopolyplex formulation was carried out. Here, negatively charged MNPs, coated with either carboxymethyldextran or citric acid, were added to preformulated cationic liposomes. The negative surface charge of the MNP allowed the successful diffusion of the MNPs through the positively charged lipid membrane to form magnetoliposomes. To these magnetoliposomes co-condensed pDNA and K16 peptides was also added, ultimately forming magnetolipopolyplexes. Dynamic light scattering and zetapotential characterisation data confirmed the successful formulation of the magnetolipopolyplexes and subsequent in vitro transfection studies were carried out to establish the transfection efficiency of the magnetolipopolyplexes by measuring the RFP expression of the pDNA. SQUID magnetometry data was obtained to determine the concentration of the MNPs taken up into the cells following the incubation of the cells with the magnetlipopolyplexes. The encapsulation of MNPs, pDNA and peptides into liposomes demonstrates the successful formulation of a multimodal-imaging agent with the potential for optical, PET and MRI imaging modalities.
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Schifino, Valente Ana Luisa. "Diagnostic imaging of the Loggerhead sea turtle (Caretta caretta)." Doctoral thesis, Universitat Autònoma de Barcelona, 2007. http://hdl.handle.net/10803/5744.
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The aims of this work are:1. To provide the normal cervical and coelomic radiographic appearance of the Loggerhead sea turtle, in the dorso-ventral view, as well as other useful landmarks, to allow for correlation of shell scutes with internal anatomic structures.
2. To provide the normal radiographic anatomy of the limbs of the Loggerhead sea turtle in combination with data obtained from computed tomography - osteological, gross anatomical and histological data.
3. To describe the normal ultrasonographic appearance of cervical structures and coelomic organs of the Loggerhead sea turtle, and to provide the respective images of frozen cross-sections for anatomical reference.
4. To provide normal computed tomographic images of the vertebral column and coelomic structures of the Loggerhead sea turtle, by establishing reference standards for organ size and position in this species; to provide images of virtual tracheo-bronchoscopy and 3D reconstructions of the respiratory tract and bone structures.
5. To provide the normal magnetic resonance imaging (MRI) appearance of coelomic structures of Loggerhead sea turtles in T1 and T2-weighted scans via comparison with cross-sectional anatomic sections of this species.
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Wagner, Wencke M. "Diagnostic imaging of the normal common marmoset (Callithrix jacchus)." Diss., University of Pretoria, 2004. http://upetd.up.ac.za/thesis/available/etd-06282005-111803/.
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Renkoski, Timothy Eli. "Autofluorescence-Based Diagnostic UV Imaging of Tissues and Cells." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/301767.
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Cancer is the second leading cause of death in the United States, and its early diagnosis is critical to improving treatment options and patient outcomes. In autofluorescence (AF) imaging, light of controlled wavelengths is projected onto tissue, absorbed by specific molecules, and re-emitted at longer wavelengths. Images of re-emitted light are used together with spectral information to infer tissue functional information and diagnosis. This dissertation describes AF imaging studies of three different organs using data collected from fresh human surgical specimens. In the ovary study, illumination was at 365 nm, and images were captured at 8 emission wavelengths. Measurements from a multispectral imaging system and fiber optic probe were used to map tissue diagnosis at every image pixel. For the colon and pancreas studies, instrumentation was developed extending AF imaging capability to sub-300 nm excitation. Images excited in the deep UV revealed tryptophan and protein content which are believed to change with disease state. Several excitation wavelength bands from 280 nm to 440 nm were investigated. Microscopic AF images collected in the pancreas study included both cultured and primary cells. Several findings are reported. A method of transforming fiber optic probe spectra for direct comparison with imager spectra was devised. Normalization of AF data by green reflectance data was found useful in correcting hemoglobin absorption. Ratio images, both AF and reflectance, were formulated to highlight growths in the colon. Novel tryptophan AF images were found less useful for colon diagnostics than the new ratio techniques. Microscopic tryptophan AF images produce useful visualization of cellular protein content, but their diagnostic value requires further study.
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Ofori, Eric Kwasi. "Development of quality standards for diagnostic imaging in Ghana." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.511043.
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Shallof, Abulgasim M. "Multi-frequency electrical impedance tomography for medical diagnostic imaging." Thesis, University of Sheffield, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265987.
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Pye, Stephen Dominic. "Medical ultrasonics : adaptive time gain compensation in diagnostic imaging." Thesis, University of Edinburgh, 1987. http://hdl.handle.net/1842/29955.
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Denniss, Jonathan. "Diagnostic imaging and the structure-function relationship in glaucoma." Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/diagnostic-imaging-and-the-structurefunction-relationship-in-glaucoma(24b94e53-d0b9-4437-a639-8ea739049d22).html.
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This thesis describes a series of investigations into the use of optic nerve head (ONH) imaging in primary open-angle glaucoma (POAG), and its relation to visual function. Accurate diagnosis is a key issue in POAG, particularly the difficult task of separating those with early disease from those healthy individuals who display signs of POAG. The purpose of this work is to improve diagnostic methods in glaucoma through use of ONH imaging and its relationship with visual field (VF) loss. First, the performance of a group of expert clinicians evaluating ONH photographs for glaucomatous damage was investigated. The results showed that even when their assessments are combined discrimination between eyes with and without POAG (based on VF loss) is far from perfect, highlighting the need for improvements in diagnosis. The possibility of combining structural and functional data to aid diagnosis was then considered. This requires VF loss and ONH damage to be strongly topographically related. The strength of this relationship was evaluated in 185 patients with POAG. 10,000 computer-generated maps between the ONH and VF were tested and the topographic relationship measured with each of these was compared to that using a published structure-based map. The weak topographic relationships found suggest that the application of these maps to individual patients is limited with current measures. The next chapter describes how a multispectral imaging (MSI, also called hyperspectral imaging) system was set-up for spatial evaluation of ONH oxygenation using a Beer-Lambert law model. Test-retest repeatability was tested and found to be acceptable for the purposes of the following studies. The MSI system was then used for an investigation of the relationship between ONH oxygenation and VF loss. 33 eyes of 18 patients underwent VF testing, MSI and HRT3 imaging. Superior-inferior asymmetries in VF sensitivity were compared to superior-inferior asymmetries in ONH oxygenation measured by MSI and in neuroretinal rim (NRR) area measured by HRT3. This way we take advantage of the typical progression of POAG and each eye acts as its own reference, negating the effect of a wide normal range and overlap between health and disease. This study found, for the first time, a strong association between ONH oxygenation and VF sensitivity. A re-analysis of the 33 ONH oxygenation maps was then performed to assess oxygenation only in the area of the NRR as defined by the HRT. Superior-inferior asymmetries in NRR oxygenation were then compared to superior-inferior asymmetries in VF loss, and the associations found were similarly strong. This study shows that MSI is capable of detecting areas of NRR deemed healthy tissue by structural imaging techniques, which are in fact poorly oxygenated and associated with VF defects. These findings show that NRR oxygenation measured by MSI is strongly related to VF loss. This important information complements existing technologies and may aid in the future diagnosis and management of patients with POAG.
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Jackson, Daniel Lee. "Diagnostic technologies for stroke related events : an economic evaluation." Thesis, University of Surrey, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.576120.
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Abstract Stroke is a very serious medical condition, taking place when there is an interruption in the blood supply to the brain. A related condition, the transient ischaemic attack {TIA}, occurs when the brain's blood supply is temporarily interrupted, and a short episode of neurological dysfunction is experienced by the patient. Understanding the impact of Stroke and TIA on healthcare provision is important. One publication presented here reports a prospective telephone survey undertaken on healthcare providers in Europe and the United States of America, examining the current diagnosis and management of TIA patients. We identified similarities in practice patterns for TIA across countries, although there were variations, such as the patient's point of entry to care and their subsequent follow up. I also review the literature published {since 2000} to determine any trends seen in the incidence, prevalence and mortality associated with Stroke in Europe and the United States. This publication found that Stroke is still a very large public health burden, although there is a continued trend of decreasing Stroke mortality. Economic modelling was undertaken to assess the relative cost effectiveness of diagnostic techniques in rapidly identifying the appropriate patients for post-TIA care in the United Kingdom. This paper presents a deterministic 1 year economic model, and suggests that an alternative pathway of care incorporating rapid access to diagnostic technologies for TIA patient assessment realised cost savings when compared to a modelled current standard of care. Three papers presented here examine the relative cost effectiveness of employing additional diagnostic techniques to facilitate the rapid diagnosis, and subsequent appropriate treatment of acute Ischaemic Stroke patients, through the use of decision analytic techniques. I examine the relative cost effectiveness of the use of an additional MRI technique to identify ischemic stroke patients suitable for treatment in the United States, the cost-effectiveness of employing an additional CT perfusion imaging step to assess these patients, and finally I assess the relative cost-effectiveness of using either an additional MRI or an additional CT based selection technique within the context of the NHS in the UK. The findings from these papers suggest that if diagnostic equipment and facilities exist, then when employed within an appropriate clinical care pathway, their application in Stroke and TIA diagnosis and treatment can be considered to be one of their potentially cost effective uses. 2
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Chang, Yiu-chuen, and 張耀泉. "Super resolution technique and its potential usage in medical imaging." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/198844.
Full textAbstract:
Purpose:
Medical imaging systems are used to scan patients to obtain valuable information for diseases diagnosis and assisting treatment. An ideal scanner should be sensitive enough to detect any trace amount of abnormal tissue at its early stage. With the continuous development of high-tech treatment systems such as Tomotherapy (manufactured by Tomo HD), the high-resolution imaging system is favorable to reduce the damage of normal tissue due to the image guidance of Mega-voltage beam before treatment. In this study, a software approach was presented to improve image resolution without hardware upgrade of a scanner.
Methodology
A programming technique “Super Resolution Technique” was used and demonstrated in an example of CT. It utilized several similar images with known relative shifts between them. (They can be positional or angular shifted and taken at the same time frame as far as possible). Those images are of low resolution and can be reconstructed to form a higher resolution image. A Super Resolution program was written by MATLAB to prove the method. The experiments 1 to 4 were purely computer-based simulations and experiment 5 used a LightSpeed VCT scanner for real scans. For the computer-based experiments, a few low resolution images have been attempted and registration steps were explored for image reconstruction. A resolution target, USAF1951, was called from MATLAB and used to examine the resolving power before and after image processing based on Super Resolution algorithm. Image-image subtraction was used to compare pre-processing and post-processing images. The number of non-zero pixels was used to access the percentage of similarity. For the experiment using LightSpeed VCT scanner, a GE VCT QA phantom was used to test the performance of the technique.
Result
From the experiments using USAF1951, it was found that: the minimum resolvable line pairs had improved from family -1 element 6 to family 0 element 2 (2 elements improvement) after applying “Super Resolution Technique” as shown in the experiment 1. An xy directional shifting of the pre-processing images resulted in a better reconstructed image than x-axis shifting or y-axis shifting in terms of resolution, shown in the experiment 2. The experiment 3 concluded that the more the pre-processing images, the better the reconstructed image would be. The experiment 4 showed that the shifts of pre-processing images greater than the detector size could still result in a higher resolution image. The experiment 5 revealed that applying “Super Resolution Technique” to a real CT scanner could not give an obvious improvement in resolution, but the image background noise had reduced.
Conclusion
It was concluded that the “Super Resolution Technique” could improve the image resolution and reduce the background noise at expense of more imaging time and more dose from the additional view. In case of hardware upgrade of imaging device is not practicable, Super Resolution could help improve the image quality.published_or_final_version
Medical Sciences
Master
Master of Medical Sciences
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MYERS, KYLE JEAN. "VISUAL PERCEPTION IN CORRELATED NOISE (MODELS)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188006.
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This dissertation concerns the ability of human observers to perform detection tasks in medical images that contain structured noise. We shall show that physical measures of image quality, such as signal-to-noise ratio (SNR), resolution, modulation transfer function (MTF), and contrast, do not accurately predict how well an observer can detect lesions in an image. We have found that for images with equal pixel SNR, humans can detect a low contrast object more readily in images that have a low-pass noise structure, as opposed to a high-pass noise structure. This finding is important in the comparison of images generated by a classical pinhole imaging system with images generated by a computed tomography imager. We would like to have a figure of merit that accurately predicts a physician's ability to perform perceptual tasks. That is, we want a figure of merit for imaging systems that is more than an evaluation of the physician's performance, measured using human observers and an accepted method such as receiver operating characteristic (ROC) techniques. We want a figure of merit that we can calculate without requiring lengthy observer studies. To perform this calculation, we need a model of the imaging system hardware in cascade with a verified model of the human observer. We have chosen to approach this problem by modelling the human observer as an ideal observer. Our hypothesis is that the human observer acts approximately as an ideal-observer who does not have the ability to prewhiten the noise in an image. Without this ability, the ideal observer's detection performance for even a simple task is degraded substantially in correlated noise. This is just the effect that we have found for human observers. In search of a physiological explanation for a human observer's inability to do prewhitening, we shall investigate the detection capability of the ideal observer when a frequency-selective mechanism is invoked. This mechanism corresponds to the frequency channels known to exist in the human visual system. We shall show that the presence of such a mechanism can explain the degradation of human observer performance in correlated noise.
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Raubenheimer, Lauren. "Corpus callosum morphology in children on mid-sagittal MR imaging." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29692.
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Background: There is little published research on the wide variation of corpus callosum (CC) morphology in children, the assessment of which is made difficult by the complex alteration of its appearance in childhood. Objective: The purpose of our study was to assess the morphology of the CC on mid-sagittal T1- weighted magnetic resonance imaging (MRI) in a large number of children and correlate the findings with demographic and clinical criteria. Materials and methods: We reviewed all brain mid-sagittal T1-weighted MRI’s performed from July to December 2015 and obtained relevant demographic and clinical information from the accompanying report and laboratory system. The CC morphology was analysed by three radiologists and compared using cross tabulation with the chi-square test and ANOVA. Interobserver correlation was assessed using Kappa coefficient of conformance. Results: 257 patients with mean age 72±60 months were included, 142 were male (55%). In abnormal MRI’s the CC was less likely to have an identifiable isthmus and was more likely to be convex, thin and have separation of the fornix insertion (all p<0.01). In young children (< 5 years) the CC was also less likely to have an identifiable isthmus (p=0.01) and was more likely to be convex (p=0.04) but the fornix was more likely to insert normally (p<0.01). Children with tuberous sclerosis had significantly thinner splenia (p=0.02). Conclusion: There is a distinct pathological appearance of the CC. The immature appearance of the corpus callosum can mirror this but is distinguished by normal insertion of the fornix and normal quantitative measurements. Splenial thinning in children with tuberous sclerosis warrants further investigation.
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York, George W. P. "Architecture and algorithms for a fully programmable ultrasound system /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/5931.
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Bossart, Elizabeth L. "Magnetic resonance imaging and spectroscopy for the study of translational diffusion applications to nervous tissue /." [Florida] : State University System of Florida, 1999. http://etd.fcla.edu/etd/uf/1999/amj9926/bossart.pdf.
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Thesis (Ph. D.)--University of Florida, 1999.Title from first page of PDF file. Document formatted into pages; contains xiv, 137 p.; also contains graphics. Vita. Includes bibliographical references (p. 129-136).
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Stöckmann, Henning. "The development of new agents for molecular imaging in cancer." Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610030.
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Bashri, Mohd Saiful Riza. "Wearable devices for microwave head diagnostic systems." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33243.
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Although current head imaging technologies such as magnetic resonance imaging (MRI) and computed tomography (CT) are capable of providing accurate diagnosis of brain injuries such as stroke and brain tumour, they have several limitations including high cost, long scanning time, bulky and mostly stationary. On the other hand, radar-based microwave imaging technology can offer a low cost, non-invasive and non-ionisation method to complement these existing imaging techniques. Moreover, a compact and wearable device for microwave head imaging is required to facilitate frequent or real-time monitoring of a patient by providing more comfort to the patient. Therefore, a wearable head imaging device would be a significant advantage compared to the existing wideband microwave head sensing devices which typically utilise rigid antenna structure. Furthermore, the wearable device can be integrated into different microwave imaging setups such as real-time wearable head imaging systems, portable systems and conventional stationary imaging tools for use in hospitals and clinics. This thesis presents the design and development of wearable devices utilising flexible antenna arrays and compact radio frequency (RF) switching circuits for wideband microwave head imaging applications. The design and characterisation of sensing antennas using flexible materials for the wearable head imaging device are presented in the first stage of this study. There are two main variations of monopole antennas that have been developed in this research, namely trapezoidal and elliptical configurations. The antennas have been fabricated using different flexible substrate materials such as flexible FR-4, polyethylene terephthalate (PET) and textile. Wideband performances of the antennas have been achieved by optimising their co-planar waveguide feeding line structures. Importantly, the efficiencies of the fabricated antennas have been tested using a realistic human head phantom by evaluating their impedance matching performances when operating in close proximity to the head phantom. The second stage of the study presents the development of wearable antenna arrays using the proposed flexible antennas. The first prototype has been built using an array of 12 flexible antennas and a conformal absorbing material backed with a conductive sheet to suppress the back lobe radiation of the monopole antennas. Additionally, the absorber also acts as a mounting base to hold the antennas where the wearable device can be comfortably worn like a hat during the measurement and monitoring processes. The effect of mutual coupling between adjacent antennas in the array has been investigated and optimised. However, the use of the absorbing material makes the device slightly rigid where it can only be fitted on a specific head size. Thus, a second prototype has been developed by using a head band to realise a stretchable configuration that can be mounted on different sizes of human heads. Furthermore, due to the stretchable characteristic of the prototype, the antennas can be firmly held in their positions when measurements are made. In addition, fully textile based sensing antennas are employed in this prototype making it perfectly suitable for monitoring purposes. Low cost and compact switching circuits to provide switching mechanism for the wearable antenna array are presented in the third stage of this study. The switching circuit is integrated with the antenna array to form a novel wearable microwave head imaging device eliminating the use of external bulky switching network. The switching circuit has been built using off-the-shelf components where it can be controlled wirelessly over Bluetooth connection. Then, a new integrated switching circuit prototype has been fabricated using 6-layer printed circuit board (PCB) technology. For the purpose of impedance matching for the radio-frequency (RF) routing lines on the circuit, a wideband Microstrip-to-Microstrip transition is utilised. The final stage of this study investigates the efficacy and sensitivity of the proposed wearable devices by performing experiments on developed realistic human head phantoms. Initially, a human head phantom has been fabricated using food-based ingredients such as tap water, sugar, salt, and agar. Subsequently, lamb's brains have been used to improve the head phantom employed in the experiments to better mimic the heterogeneous human brain. In terms of imaging process, an interpolation technique developed using experimental data has been proposed to assist the localisation of a haemorrhage stroke location using the confocal delay-and-sum algorithm. This new technique is able to provide sensible accuracy of the location of the blood clot inside the brain. The wearable antenna arrays using flexible antennas and their integrations with compact and low cost switching circuits reported in this thesis make valuable contribution to microwave head imaging field. It is expected that a low-cost, compact and wearable radar-based microwave head imaging can be fully realised in the future for wide range of applications including static scanning setup in hospitals, portable equipment in ambulances and as a standalone wearable head monitoring system for remote and real-time monitoring purposes.
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Kairdolf, Brad A. "Development of polymer-coated nanoparticle imaging agents for diagnostic applications." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31845.
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Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2010.Committee Chair: Nie, Shuming; Committee Member: Bao, Gang; Committee Member: Murthy, Niren; Committee Member: Varma, Vijay; Committee Member: Wang, Zhong Lin. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Torkzad, Michael R. "Magnetic resonance imaging of rectum : diagnostic and therapy related aspects /." Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-734-0/.
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Turetsky, Anna. "Companion Imaging Probes and Diagnostic Devices for B-Cell Lymphoma." Thesis, Harvard University, 2014. http://nrs.harvard.edu/urn-3:HUL.InstRepos:13094356.
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As new therapeutic targets and drugs are discovered for B-cell lymphoma and other cancers, companion diagnostics are also needed to determine target engagement, therapeutic efficacy, and patient segmentation for clinical trials. We first employed synthetic chemistry to build a platform for modifying small molecule drugs into imaging probes, using the poly(ADP-ribose) polymerase 1 (PARP1) inhibitor AZD2281 (Olaparib) as a model for technology development. Our results showed that small-molecule companion imaging drugs can be used for fluorescence imaging in cells, as well as for pharmacokinetic studies and positron emission tomography (PET) imaging in vivo, without significantly perturbing their target binding properties or cellular uptake. To apply this approach to B-cell lymphoma drugs currently in clinical trials, we modified an irreversible inhibitor of Bruton's Tyrosine Kinase (BTK), PCI-32765 (Ibrutinib), with the fluorophore Bodipy FL (BFL), and used it for imaging in cells and in a mouse window-chamber xenograft model. The excellent co-localization of our probe (Ibrutinib-BFL) with BTK demonstrated its utility for studying additional BTK inhibitors and as a companion imaging probe. In parallel, we hypothesized that central nervous system (CNS) lymphoma diagnosis from paucicellular cerebrospinal fluid (CSF) samples could be improved with molecular profiling of putative lymphoma cells trapped in a customized microfluidic chip. Following fabrication and characterization of a polydimethylsiloxane (PDMS) diagnostic device containing an array of affinity-free single-cell capture sites, we were able to efficiently recover >90% of lymphocytes, perform immunostaining on chip, and apply an image-processing algorithm to group cells based on their molecular marker expression, such as kappa/lambda light chain restriction. Additionally, in combination with Ibrutinib-BFL or other imaging drugs, we demonstrated the potential for on-chip drug imaging for use in conjunction with drug development. Finally, we applied bioorthogonal conjugation chemistries on cellulose paper for potential applications in lowering the cost of drug screening. We anticipate that these approaches will enable direct, molecular information for personalized treatment decisions in B-cell lymphomas, as well as provide a roadmap for the development of companion diagnostic probes and devices for additional indications.
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Rodriguez, Solimar Reyes. "Optical coherence tomography and microwave imaging diagnostic techniques for osteoporosis /." Diss., Connect to online resource - MSU authorized users, 2008.
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Li, Zeyang. "Development of VHH- and antibody- based imaging and diagnostic tools." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/118269.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references.
The immune system distinguishes self from non-self to combat pathogenic incursions. Evasion tactics deployed by viruses, microbes, or malignant cells may impede an adequate response. In such cases, therapeutic interventions aid in the elimination of pathogens and the restoration of physiological homeostasis. A major road block in the development of such therapies is the reliance on imperfect detection methods to identify site(s) of infection, or to monitor immune cell recruitment to sites of infection or inflammation in vivo. The goal of this thesis is overcome at least some of these limitations by utilizing novel tools that have been developed and refined in the laboratory to facilitate in vitro and in vivo characterization of specific immune subsets. We then track their recruitment to sites of active immune responses, such as infection or tumor progression sites. These tools consist of two components: one that confers specificity for immune cells and the other offers a site for labeling in a controlled manner. Single-domain antibodies (VHHs) from camelids are amongst the smallest (15 KDa) proteins that can recognize a diverse set of targets with excellent specificity. Chemoenzymatic labeling of molecules using sortase allows site-specific attachment of a single label of interest to the target protein containing the sortase recognition sequence LPXTG. VHHs specific for immune cell determinants labeled with sortase technology facilitate non-invasive and efficient monitoring of cells that infiltrate immunological niches in vivo in a manner not possible until now. This thesis presents the development of novel methods to allow in vitro and in vivo detection and imaging of specific immune subsets and their recruitment to sites of an active immune response. This thesis aims to (1) use DNA oligomers as a scaffold to push the limits of fluorescence labelling yield (2) create small and efficient biosensors for the rapid capture of specific lymphocyte subsets from peripheral blood samples using VHHs and graphene oxide nanosheets (3) develop radioisotope-labeled VHHs to track immune cell subsets to elucidate the roles of innate and adaptive immune components in the course of infection. Chapter 1 describes a new method for protein labeling via site-specific modification of proteins using a DNA scaffold. To avoid self-quenching of multiple fluorophores localized in close proximity, Holliday junctions were used to label proteins site-specifically with fluorophores. Holliday junctions enable the introduction of multiple fluorophores with reasonably precise spacing to improve fluorescence yield for both single domain and full-sized antibodies, without deleterious effects on antigen binding. Chapter 2 presents a biosensor generated for characterization of leukocytes from whole blood using a graphene oxide surface coated with single domain antibody fragments. This format allows quick and efficient capture of distinct white blood cell subpopulations from small samples of whole blood in a format that does not require any specialized equipment such as cell sorters or microfluidic devices. Chapter 3 documents a non-invasive immune-PET imaging method for tracing CD8+ T cells in the course of influenza A infection to better elucidate their protective mechanism(s) and immunopathological effects.
by Zeyang Li.
Ph. D.
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Herz, Paul Richard 1972. "Minimally invasive diagnostic imaging using high resolution Optical Coherence Tomography." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/28714.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.Includes bibliographical references.
Advances in medical imaging have given researchers unprecedented capabilities to visualize, characterize and understand biological systems. Optical Coherence Tomography (OCT) is a high speed, high resolution imaging technique that utilizes low coherence interferometry to perform cross-sectional tomographic imaging of tissue in real time and in vivo. The design, development, and implementation of ultrahigh resolution OCT systems in both laboratory and clinical experiments has been pursued in this work. Biomedical imaging studies in the areas of arthroscopy, cardiology, and endoscopy have been investigated with ultrahigh resolution capability achieved through the use of broadband femtosecond oscillators such as Ti:Sapphire and Cr:Forsterite light sources. OCT image resolutions of 1-5um in tissue have been realized, an order of magnitude greater than conventional MRI or ultrasound resolutions. In addition, through the use of coherent heterodyne detection techniques, the capability to visualize pathological tissue architecture in vivo for both animal and human experimental trials has been demonstrated. Because OCT can perform such "optical biopsy" with resolutions approaching that of conventional excisional biopsy and histology, it has the potential to become a powerful diagnostic tool in the field of medical imaging. In combination with small fiber-optic catheters, endoscopes, and other imaging devices, minimally invasive OCT imaging was carried out with novel diagnostic devices also developed in this work. The development and implementation of advanced OCT systems for both research and clinical applications will be presented as well as future directions for the technology.
by Paul R. Herz.
Ph.D.
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Stewart, Rachel Christine. "A diagnostic imaging technique and therapeutic strategy for early osteoarthritis." Thesis, Boston University, 2014. https://hdl.handle.net/2144/12949.
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Thesis (Ph.D.)--Boston UniversityOsteoarthritis (OA) is a chronic, progressive disease of diarthrodial joints arising from the breakdown of articular cartilage. As one of the leading causes of disability and lifestyle limitations in the United States, osteoarthritis is estimated to affect 27 million people in the U.S. and cost the economy $128 billion annually. Current diagnostic techniques detect OA only in its later stages, when irreversible cartilage damage has already occurred. A reliable, non-invasive method for diagnosing OA in its early stages would provide an opportunity to intervene and potentially to stay disease progression. Likewise, the field of OA research would benefit from a technique that allows tissue engineering and small molecule therapies to be evaluated longitudinally. Contrast-enhanced computed tomography (CECT) of cartilage is a developing medical imaging technique for evaluating cartilage biochemical and biomechanical properties. CECT has been shown to accurately quantify measures of cartilage integrity such as glycosaminoglycan (GAG) content, equilibrium compressive modulus, and coefficients of friction. In the studies presented herein, cationic iodinated contrast agents are developed for quantitative cartilage CECT, a technique predicated on the diffusion and partitioning of a charged contrast agent into the cartilage. The experiments show that cationic contrast agents lack specific interactions with anionic GAGs and are highly taken up in cartilage due, instead, to their electrostatic attraction. At diffusion equilibrium, both anionic and cationic agents indicate GAG content and biomechanical properties as measured by microcomputed tomography, though cationic contrast agents were found to diffuse through cartilage more slowly than anionic ones. Translating CECT to intact joints with clinically available helical CT scanners bears promising results, but concerns remain regarding in vivo applicability. Anionic contrast agents enable GAG content quantification following brief contrast agent exposure, whereas cationic agents require full equilibration within the tissue. To explore treatment modalities for early OA, a novel interpenetrating hydrogel method was developed to reconstitute the mechanical properties of cartilage models for early OA. Preliminary results show that the interpenetrating network strengthened cartilage with respect to compressive loading suggesting that the treatment could potentially serve as a functional replacement for GAG lost in the early stages of OA.
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Kirberger, Robert M. "Diagnostic imaging aspects of Spirocerca lupi infection in the dog." Thesis, University of Pretoria, 2013. http://hdl.handle.net/2263/32980.
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This collection of one book chapter and 12 peer reviewed scientific papers comprises of 7 chapters. The first chapter starts with a 2008 review article as an introduction. This was a comprehensive review of Spirocerca lupi with an extensive section on diagnostic imaging, which included the value of computed tomography. The second publication in the first chapter deals with our first paper in 2001 which described in detail the radiographic characteristics of the spondylitis reactions as well as the oesophageal masses, which could be typical or atypical. Aortic aneurysm formation as well as aortic mineralisation visibility was also reported on. Additionally, the value of computed tomography (CT) in spirocercosis was elucidated for the first time. This is the first S. lupi article to extensively describe the imaging findings from a radiological viewpoint and to combine these with the clinical findings. To date this paper is still regularly referenced.
The second chapter emphasizes the value of a variety of radiographic techniques, including pneumoesophagography, to optimize the diagnosis of spirocercosis as a primary imaging modality. Radiography remains the cheapest and most readily accessible diagnostic imaging technique and as such making the correct technical decisions, as proven in these 3 papers,
optimizes diagnostic capabilities in a cost‐effective way for the first time.
The third chapter examines the value of CT and alternative imaging techniques in S. lupi
associated disorders to diagnose spirocercosis and its complications. These include the limited value of ultrasonography and the very important role CT, as well as CT angiography, has to play. Computed tomography was shown to play a major role in detecting aortic changes, in decision‐making for surgical removal of neoplastic oesophageal masses, as well as in detecting and determining the extent of secondary changes associated with spirocercosis. The value of CT, first described by us in 2001, is amplified in these publications and has become an essential imaging tool to manage this disease. Magnetic resonance imaging is not available at the Onderstepoort Veterinary Academic Hospital and as such was not addressed in this dissertation. However, its primary use in spirocercosis is in diagnosing
aberrant larval migration to the vertebral canal.
The fourth chapter discusses the perplexing matter of malignant transformation of the S.
lupi associated benign oesophageal nodule and how to diagnose it. This is an on‐going
investigation in our department, but this chapter contains the first publication that linked
diagnostic imaging findings with clinical parameters in an attempt to determine if malignant transformation of the nodule had taken place. The latter is vitally important in determining prognosis and treatment. Once malignancy is present, metastatic spread can take place to many parts of the body. Two case reports are presented with hitherto undescribed metastatic spread to the central nervous system from the primary oesophageal neoplasm.
The fifth chapter looks at the pathomechanisms of spondylitis formation in spirocercosis by means of a radiological‐pathological investigation. This is the first in‐depth veterinary investigation on how vertebral new bone formation takes place and whether inflammation plays a role.
The sixth chapter, consisting of a review paper published in 2010, brought together more
recent thoughts on some of the dilemmas still facing clinicians in the diagnosis and
treatment of spirocercosis.
The final chapter concludes with a discussion of the most appropriate imaging procedures to use in diagnosing spirocercosis and its complications. Additionally challenges remaining and future research directions are considered.Thesis (DVSc)--University of Pretoria, 2013.
gm2013
Companion Animal Clinical Studies
unrestricted
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Tang, Mei-yee. "Medical imaging : applications of functional magnetic resonance imaging and the development of a magnetic resonance compatible ultrasound system /." View the Table of Contents & Abstract, 2006. http://sunzi.lib.hku.hk/hkuto/record/B36749710.
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Tang, Mei-yee, and 鄧美宜. "Medical imaging: applications of functional magnetic resonance imaging and the development of a magnetic resonancecompatible ultrasound system." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37897688.
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