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Tesi sul tema "Imaging systems in medicine"
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1
Nadeau, Valerie J. "Fluorescence imaging and spectroscopy systems for cancer diagnostics". Thesis, University of Glasgow, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269513.
Testo completo
2
Raichur, Rohan. "A novel technique to improve the resolution & contrast of planar nuclear medicine imaging". Akron, OH : University of Akron, 2008. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1226955205.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of Akron, Dept. of Biomedical Engineering, 2008."December, 2008." Title from electronic thesis title page (viewed 12/13/2009) Advisor, Dale H. Mugler; Co-Advisor, Anthony M. Passalaqua; Committee members, Daniel B. Sheffer; Department Chair, Daniel B. Sheffer; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
3
Dhillon, Ravinder. "Diagnostic imaging pathways /". Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0126.
Testo completo
4
Pao, Tsang-Long. "Ultrasonic tapered phased arrays for three-dimensional imaging". Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/13541.
Testo completo
5
Eljaaidi, Abdalla Agila. "2D & 3D ultrasound systems in development of medical imaging technology". Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2193.
Testo completoAbstract (sommario):
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016.Ultrasound is widely used in most medical clinics, especially obstetrical clinics. It is a way of imaging methods that has important diagnostic value. Although useful in many different applications, diagnostic ultrasound is especially useful in antenatal (before delivery) diagnosis. The use of two-dimensional ultrasound (2DUS) in obstetrics has been established. However, there are many disadvantages of 2DUS imaging. Several researchers have published information on the significance of patients being shown the ultrasound screen during examination, especially during three- and four-dimensional (3D/4D) scanning. In addition, a form of ultrasound, called keepsake or entertainment ultrasound, has boomed, particularly in the United States. However, long-term epidemiological studies have failed to show the adverse effects of ultrasound in human tissues. Until now, there is no proof that diagnostic ultrasound causes harm in a human body or the developing foetus when used correctly. While ultrasound is supposed to be absolutely safe, it is a form of energy and, as such, has effects on tissues it traverses (bio-effects). The two most important mechanisms for effects are thermal and non-thermal. These two mechanisms are indicated on the screen of ultrasound devices by two indices: The thermal index (TI) and the mechanical index (MI). These are the purposes of this thesis: • evaluate end-users’ knowledge regarding the safety of ultrasound; • evaluate and make a comparison between acoustic output indices (AOI) in B-mode (2D) and three-dimensional (3D) ultrasound – those measured by thermal (TI) and mechanical (MI) indices; • assess the acoustic output indices (AOI) to benchmark current practice with a survey conducted by the British Medical Ultrasound Society (BMUS); and • review how to design 2D and 3D arrays for medical ultrasound imaging
6
Wild, Walter James. "Gamma-ray imaging probes". Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184331.
Testo completoAbstract (sommario):
External nuclear medicine diagnostic imaging of early primary and metastatic lung cancer tumors is difficult due to the poor sensitivity and resolution of existing gamma cameras. Nonimaging counting detectors used for internal tumor detection give ambiguous results because distant background variations are difficult to discriminate from neighboring tumor sites. This suggests that an internal imaging nuclear medicine probe, particularly an esophageal probe, may be advantageously used to detect small tumors because of the ability to discriminate against background variations and the capability to get close to sites neighboring the esophagus. The design, theory of operation, preliminary bench tests, characterization of noise behavior and optimization of such an imaging probe is the central theme of this work. The central concept lies in the representation of the aperture shell by a sequence of binary digits. This, coupled with the mode of operation which is data encoding within an axial slice of space, leads to the fundamental imaging equation in which the coding operation is conveniently described by a circulant matrix operator. The coding/decoding process is a classic coded-aperture problem, and various estimators to achieve decoding are discussed. Some estimators require a priori information about the object (or object class) being imaged; the only unbiased estimator that does not impose this requirement is the simple inverse-matrix operator. The effects of noise on the estimate (or reconstruction) is discussed for general noise models and various codes/decoding operators. The choice of an optimal aperture for detector count times of clinical relevance is examined using a statistical class-separability formalism.
7
Zhu, Hui. "Deformable models and their applications in medical image processing /". Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20717970.
Testo completo
8
Liew, Soo Chin. "Thermoacoustic emission induced by deeply penetrating radiation and its application to biomedical imaging". Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184783.
Testo completoAbstract (sommario):
Thermoacoustic emissions induced by 2450 MHz microwave pulses in water, tissue-simulating phantoms and dog kidneys have been detected. The analytic signal magnitude has been employed in generating 'A-mode' images with excellent depth resolution. Thermoacoustic emissions have also been detected from the dose-gradient at the beam edges of a 4 MeV x-ray beam in water. These results establish the feasibility of employing thermoacoustic signals in generating diagnostic images, and in locating x-ray beam edges during radiation therapy. A theoretical model for thermoacoustic imaging using a directional transducer has been developed, which may be used in the design of future thermoacoustic imaging system, and in facilitating comparisons with other types of imaging systems. A method of characterizing biological tissues has been proposed, which relates the power spectrum of the detected thermoacoustic signals to the autocorrelation function of the thermoacoustic source distribution in the tissues. The temperature dependence of acoustic signals induced by microwave pulses in water has been investigated. The signal amplitudes vary with temperature as the thermal expansion of water, except near 4°C. The signal waveforms show a gradual phase change as the temperature changes from below 4° to above 4°C. This anomaly is due to the presence of a nonthermal component detected near 4°C, whose waveform is similar to the derivative of the room temperature signal. The results are compared to a model based on a nonequilibrium relaxation mechanism proposed by Pierce and Hsieh. The relaxation time was found to be (0.20±0.02) ns and (0.13±0.02) ns for 200 ns and 400 ns microwave pulse widths, respectively. A microwave-induced thermoacoustic source capable of launching large aperture, unipolar ultrasonic plane wave pulses in water has been constructed. This source consists of a thin water layer trapped between two dielectric media. Due to the large mismatch in the dielectric constants, the incident microwaves undergo multiple reflections between the dielectric boundaries trapping the water, resulting in an enhanced specific microwave absorption in the thin water layer. This source may be useful in ultrasonic scattering and attenuation experiments.
9
Jin, Jiefu, e 金介夫. "Functional lanthanide-based nanoprobes for biomedical imaging applications". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2012. http://hub.hku.hk/bib/B47752579.
Testo completoAbstract (sommario):
Lanthanide-doped upconversion nanoparticles (UCNPs) are perceived as promising
novel near-infrared (NIR) bioimaging agents characterised by high contrast and high
penetration depth. However, the interactions between charged UCNPs and
mammalian cells have not been thoroughly studied and the corresponding
intracellular uptake pathways remain unclear.
Herein, my research work involved the use of hydrothermal method and ligand
exchange approach to prepare UCNP-PVP, UCNP-PEI, and UCNP-PAA. These
polymer-coated UCNPs demonstrated good water dispersibility, the similar size
distribution as well as similar upconversion luminescence efficiency. However, the
positively charged UCNP-PEI evinced greatly enhanced cellular uptake in
comparison with its neutral or negative counterparts, as revealed by cellular uptake
studies. Meanwhile, it was discovered that cationic UCNP-PEI could be effectively
internalized mainly through the clathrin endocytic machanism. This study is the first
report on the endocytic mechanism of positively charged lanthanide-doped UCNPs.
Furthermore, it allows us to control the UCNP-cell interactions by tuning surface
properties.
Glioblastoma multiforme (GBM) is the most common and malignant form of primary
brain tumors in humans. Small molecule MRI contrast agents are used for GBM
diagnosis and preoperative tumor margin delineation. However, the conventional
gadolinium-based contrast agents have several disadvantages, such as a relatively low
T1 relaxivity, short circulation half lives and the absence of tumor targeting efficiency.
Multimodality imaging probes provide a better solution to clearly delineate the
localization of glioblastoma.
My research work also involved the development of multimodal nanoprobes for
targeted glioblastoma imaging. Two targeted paramagnetic/fluorescence nanoprobes
were designed and synthesized, UCNP-Gd-RGD and AuNP-Dy680-Gd-RGD.
UCNP-Gd-RGD was prepared through PEGylation, Gd3+DOTA conjugation and
RGD labeling of PEI-coated UCNP-based nanoprobe core (UCNP-NH2). It adopted
the cubic NaYF4 phase, had an average size of 36 nm by TEM, and possessed a
relatively intense upconversion luminescence of Er3+ and Tm3+. It also exhibited
improved colloidal stability and reduced cytotoxicity compared with UCNP-NH2, and
a higher T1 relaxivity than Gd3+DOTA. AuNP-Dy680-Gd-RGD was synthesized
through bioconjugation of amine-modified AuNP-based nanoprobe core (AuNPPEG-
NH2) by a NIR dye (Dy680), Gd3+DOTA and RGD peptide. It demonstrated a
size of 3–6 nm by TEM, relatively strong NIR fluorescence centered at 708 nm, longterm
physiological stability, and an enhanced T1 relaxivity compared with
Gd3+DOTA.
Targeting abilities of both UCNP-Gd-RGD and AuNP-Dy680-Gd-RGD towards
overexpressed integrin αvβ3 receptors on U87MG cell surface was confirmed by their
enhanced cellular uptake visualized by confocal microscopy imaging and quantified
by ICP-MS, where their corresponding control nanoprobes were used for comparison.
Furthermore, targeted imaging capabilities of UCNP-Gd-RGD and AuNP-Dy680-Gd-
RGD towards subcutaneous U87MG tumors were verified by in vivo and ex vivo
upconversion fluorescence imaging studies and by in vivo and ex vivo NIR
fluorescence imaging and in vivo MR imaging studies, respectively. These two
synthesized targeted nanoprobes, with surface-bounded cyclic RGD peptide and
numerous T1 contrast enhancing molecules, are applicable in targeted MR imaging
glioblastoma and delineating the tumor boundary. In addition, UCNP-Gd-RGD
favors the upconversion luminescence with NIR-to-visible nature, while AuNPDy680-
Gd-RGD possesses NIR-to-NIR fluorescence, and both lead to their potential
applications in fluorescence-guided surgical resection of gliomas.published_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
10
Futterer, Patricia. "Cultural studies of science : skinning bodies in Western medicine". Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23332.
Testo completoAbstract (sommario):
This thesis explores the cultural implications underlying the medical practice of cutting human flesh. The examination focuses, in particular, on the function of representational technologies--from anatomy sketches to computer imaging--in the scientific understanding of the body in the West. By foregrounding the technologies of representation which inform and have directed a history of surgery, it is hoped that the cultural aspects of modern medicine will be made apparent. This thesis argues that while science benefitted from art to construct its image of 'the' body, it has had to rid itself of art in order to justify its empirical claims. The study concludes with a discussion of the work of the French performance artist Orlan who uses plastic surgery in a performative setting to deconstruct these very claims.
11
McDermott, Emma. "Characterisation of the osteoclast ruffled border using advanced imaging techniques". Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=236980.
Testo completoAbstract (sommario):
The osteoclast ruffled border is a highly convoluted, complex membrane that is necessary for bone resorption. It is thought to form following mass lysosomal fusion with the boneapposing plasma membrane and vesicular trafficking is vital for its formation and function. The aim of this PhD was to better understand the ultrastructure, formation and function of the ruffled border using TEM and advanced imaging techniques. Ruffled border reformation following calcitonin treatment was visualised and the stages of ruffled border formation were described. Ruffled borders in healthy and osteopetrotic osteoclasts were also imaged by TEM and characterised using a morphological grading system. The key findings of this thesis are as follows: (1) vacuoles, not lysosomes, are the primary contributors of membrane to the ruffled border and the membrane projections of the ruffled border form passively as a consequence of channel formation, not actively by membrane folding, (2) extracellular vesicles are located, and appear to be released, at the ruffled border. Various functional aspects of the ruffled border were also investigated. Vesicles near the ruffled border were identified and characterised by immunoelectron microscopy based on their content and morphology. We found no morphological defects in ruffled borders in mice deficient in Plekhm1. In osteoclasts derived from patients with a SNX10 mutation, we found that while the cells retained the capacity to form well-developed ruffled borders, they did so less often than healthy control osteoclasts. Importantly, we observed that even in a population of healthy osteoclasts, ruffled border morphology is highly heterogeneous because they are at different stages in the resorption cycle. In conclusion, the data in this thesis provide novel findings, previously unseen details regarding how resorbing osteoclasts interact with the bone surface, and have revealed unique insights into ruffled border morphology, formation and the vesicles with which it interacts.
12
FIETE, ROBERT DEAN. "THE HOTELLING TRACE CRITERION USED FOR SYSTEM OPTIMIZATION AND FEATURE ENHANCEMENT IN NUCLEAR MEDICINE (PATTERN RECOGNITION)". Diss., The University of Arizona, 1987. http://hdl.handle.net/10150/184160.
Testo completoAbstract (sommario):
The Hotelling trace criterion (HTC) is a measure of class separability used in pattern recognition to find a set of linear features that optimally separate two classes of objects. In this dissertation we use the HTC not as a figure of merit for features, but as a figure of merit for characterizing imaging systems and designing filters for feature enhancement in nuclear medicine. If the HTC is to be used to optimize systems, then it must correlate with human observer performance. In our first study, a set of images, created by overlapping ellipses, was used to simulate images of livers. Two classes were created, livers with and without tumors, with noise and blur added to each image to simulate nine different imaging systems. Using the ROC parameter dₐ as our measure, we found that the HTC has a correlation of 0.988 with the ability of humans to separate these two classes of objects. A second study was performed to demonstrate the use of the HTC for system optimization in a realistic task. For this study we used a mathematical model of normal and diseased livers and of the imaging system to generate a realistic set of liver images from nuclear medicine. A method of adaptive, nonlinear filtering which enhances the features that separate two sets of images has also been developed. The method uses the HTC to find the optimal linear feature operator for the Fourier moduli of the images, and uses this operator as a filter so that the features that separate the two classes of objects are enhanced. We demonstrate the use of this filtering method to enhance texture features in simulated liver images from nuclear medicine, after using a training set of images to obtain the filter. We also demonstrate how this method of filtering can be used to reconstruct an object from a single photon-starved image of it, when the object contains a repetitive feature. When power spectrums for real liver scans from nuclear medicine are calculated, we find that the three classifications that a physician uses, normal, patchy, and focal, can be described by the fractal dimension of the texture in the liver. This fractal dimension can be calculated even for images that suffer from much noise and blur. Given a simulated image of a liver that has been blurred and imaged with only 5000 photons, a texture with the same fractal dimension as the liver can be reconstructed.
13
Rogers, Erika. "Interactive computer simulation for instruction in magnetic resonance imaging". Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/9205.
Testo completo
14
Jones, Jonathan-Lee. "2D and 3D segmentation of medical images". Thesis, Swansea University, 2015. https://cronfa.swan.ac.uk/Record/cronfa42504.
Testo completoAbstract (sommario):
Cardiovascular disease is one of the leading causes of the morbidity and mortality in the western world today. Many different imaging modalities are in place today to diagnose and investigate cardiovascular diseases. Each of these, however, has strengths and weaknesses. There are different forms of noise and artifacts in each image modality that combine to make the field of medical image analysis both important and challenging. The aim of this thesis is develop a reliable method for segmentation of vessel structures in medical imaging, combining the expert knowledge of the user in such a way as to maintain efficiency whilst overcoming the inherent noise and artifacts present in the images. We present results from 2D segmentation techniques using different methodologies, before developing 3D techniques for segmenting vessel shape from a series of images. The main drive of the work involves the investigation of medical images obtained using catheter based techniques, namely Intra Vascular Ultrasound (IVUS) and Optical Coherence Tomography (OCT). We will present a robust segmentation paradigm, combining both edge and region information to segment the media-adventitia, and lumenal borders in those modalities respectively. By using a semi-interactive method that utilizes "soft" constraints, allowing imprecise user input which provides a balance between using the user's expert knowledge and efficiency. In the later part of the work, we develop automatic methods for segmenting the walls of lymph vessels. These methods are employed on sequential images in order to obtain data to reconstruct the vessel walls in the region of the lymph valves. We investigated methods to segment the vessel walls both individually and simultaneously, and compared the results both quantitatively and qualitatively in order obtain the most appropriate for the 3D reconstruction of the vessel wall. Lastly, we adapt the semi-interactive method used on vessels earlier into 3D to help segment out the lymph valve. This involved the user interactive method to provide guidance to help segment the boundary of the lymph vessel, then we apply a minimal surface segmentation methodology to provide segmentation of the valve.
15
Reddy, Narendra Lakshmana. "Novel insights in imaging and function of human brown adipose tissue". Thesis, University of Warwick, 2014. http://wrap.warwick.ac.uk/69397/.
Testo completoAbstract (sommario):
Phenomenal rise in prevalence of obesity and its complications has made it imperative to tackle the issue on a war footing, especially given the failure of current life style and medical approaches. Clearly, alternate means of treating obesity need to be explored. In contrast to white adipose tissue (WAT), which stores excess energy, brown adipose tissue (BAT) dissipates chemical energy in the form of heat by uncoupling oxidative phosphorylation from electron transport chain, to maintain body temperature homeostasis. Recent revelation of functionality of BAT in adult humans provides an excellent opportunity of stimulating it to increase energy expenditure, in turn causing weight loss alongside improving lipid and glucose homeostasis. This thesis sought to investigate the physiological nature of brown fat, by exploring the environmental, biophysical and behavioural factors that can activate BAT. ¹⁸Fluoro-labelled-2-deoxyglucose Positron Emission Tomography (18F-FDG PET) is currently the gold standard and the most sensitive method to study BAT and its function. These studies concluded that younger-age, lower body mass index, female sex and cooler outdoor temperatures are strong determinant factors of BAT prevalence, activity and mass. Interestingly, modest elevation of thyroid hormones in a sustained iatrogenically created thyrotoxic state did not influence any of the BAT indices, contrary to conventional wisdom of strong stimulation, thus highlighting the complexity of BAT metabolism. Arguably, BAT has a role in diet-induced thermogenesis. Manipulation of diet-induced thermogenesis by prolonging meal duration to 40 minutes resulted in excess postprandial energy expenditure loss than shorter meal duration of 10 minutes. However, prolonged meal duration had weakly positive effect on metabolic biochemical markers and no influence on pancreatic and gut hormones relevant to appetite. These studies advocate life style and behavioural public health messages of lowering thermostat in living spaces and chewing the food adequately in order to obtain potential metabolic benefits. As a follow-up of exploring BAT's physiology, a successful attempt at characterising BAT's anatomy was made through novel imaging technique of Iterative Decomposition of Echo Asymmetry and Least Squares Estimation (IDEAL) Magnetic Resonance Imaging. The first ever non-PET imaging demonstration of adult human BAT using IDEAL MRI was achieved with immunohistochemical confirmation, and provided proof of concept for developing MR as a safe, non-radiation exposure imaging biomarker of BAT. In summary, this thesis provided useful insights into environmental, anthropometrical, behavioural, and hormonal factors regulating BAT, whilst also providing a proof of principle of an imaging tool to visualise full extent of both metabolically active and inactive BAT, aiding future pursuits of BAT therapeutics to combat the global obesity epidemic.
16
Lankton, Shawn M. "Localized statistical models in computer vision". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/31644.
Testo completoAbstract (sommario):
Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2010.Committee Chair: Tannenbaum, Allen; Committee Member: Al Regib, Ghassan; Committee Member: Niethammer, Marc; Committee Member: Shamma, Jeff; Committee Member: Stillman, Arthur; Committee Member: Yezzi, Anthony. Part of the SMARTech Electronic Thesis and Dissertation Collection.
17
Steuwe, Christian. "Nonlinear photonics in biomedical imaging and plasmonics". Thesis, University of Cambridge, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.708016.
Testo completo
18
Yeates, Peter Gregory. "Tumour imaging using hCG-specific monoclonal antibodies". Thesis, The University of Sydney, 1989. https://hdl.handle.net/2123/26188.
Testo completoAbstract (sommario):
The aim of this thesis was to radiolabel two different anti-hCG antibodies with 111-indium, and to determine their specific tumour uptake and tissue biodistribution into choriocarcinoma xenografts in nude mice against 111-indium and 67-gallium citrate over 72 hours. Comparative radioimmunoscintigraphy was performed to determine the optimal imaging post injection for visualisation of tumour sites. Data manipulation using dual isotope computerised subtraction in mouse phantom models was evaluated as means of improving tumour delineation in low tumour contrast studies.
19
Roney, Timothy Joseph. "Coded-aperture transaxial tomography using modular gamma cameras". Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184950.
Testo completoAbstract (sommario):
Imaging in nuclear medicine involves the injection of a radioactive tracer into the body and subsequent detection of the radiation emanating from an organ of interest. Single-photon emission computed tomography (SPECT) is the branch of nuclear medicine that yields three-dimensional maps of the distribution of a tracer, most commonly as a series of two-dimensional slices. One major drawback to transaxial tomographic imaging in SPECT today is the rotation required of a gamma camera to collect the tomographic data set. Transaxial SPECT usually involves a large, single-crystal scintillation camera and an aperture (collimator) that together only satisfy a small portion of the spatial sampling requirements simultaneously. It would be very desirable to have a stationary data-collection apparatus that allows all spatial sampling in the data set to occur simultaneously. Aperture or detector motion (or both) is merely an inconvenience in most imaging situations where the patient is stationary. However, aperture or detector motion (or both) enormously complicate the prospect of tomograhically recording dynamic events, such as the beating heart, with radioactive pharmaceuticals. By substituting a set of small modular detectors for the large single-crystal detector, we can arrange the usable detector area in such a way as to collect all spatial samples simultaneously. The modular detectors allow for the possibility of using other types of stationary apertures. We demonstrate the capabilities of one such aperture, the pinhole array. The pinhole array is one of many kinds of collimators known as coded apertures. Coded apertures differ from conventional apertures in nuclear medicine in that they allow for overlapping projections of the object on the detector. Although overlapping projections is not a requirement when using pinhole arrays, there are potential benefits in terms of collection efficiency. There are also potential drawbacks in terms of the position uncertainty of emissions in the reconstruction object. The long-term goal of the research presented is dynamic SPECT imaging of the heart. The basic concepts and tasks involved in transaxial SPECT imaging with pinhole arrays are presented along with arguments for the combination of modular gamma cameras and pinhole arrays. We demonstrate by emulation two methods of tomographically imaging a stationary single object slice and present results for these two systems on object space grids of 10cm x 10cm and 20cm x 20cm.
20
Ghadyani, Hamid R. "Semi Automatic Segmentation of a Rat Brain Atlas". Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050305-140247/.
Testo completo
21
Wong, Yuk Lam. "Optical tracking for medical diagnosis based on active stereo vision /". View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202006%20WONGY.
Testo completo
22
Chan, Balwin Man Hong. "A miniaturized 3-D endoscopic system using active stereo-vision /". View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202002%20CHANB.
Testo completoAbstract (sommario):
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.Includes bibliographical references (leaves 106-108). Also available in electronic version. Access restricted to campus users.
23
Heffer, Erica Leigh. "Frequency-domain optical mammography for detection and oximetry of breast tumors /". Thesis, Connect to Dissertations & Theses @ Tufts University, 2004.
Cerca il testo completoAbstract (sommario):
Thesis (Ph.D.)--Tufts University, 2004.Adviser: Sergio Fantini. Submitted to the Dept. of Electrical Engineering. Includes bibliographical references (leaves 201-202). Access restricted to members of the Tufts University community. Also available via the World Wide Web;
24
Zhu, Hui, e 朱暉. "Deformable models and their applications in medical image processing". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31238075.
Testo completo
25
Lai, Di. "Independent component analysis (ICA) applied to ultrasound image processing and tissue characterization /". Online version of thesis, 2009. http://hdl.handle.net/1850/11367.
Testo completo
26
SMITH, WARREN ESCHHOLZ. "SIMULATED ANNEALING AND ESTIMATION THEORY IN CODED-APERTURE IMAGING (RECONSTRUCTION, MONTE CARLO, WIENER FILTER)". Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188135.
Testo completoAbstract (sommario):
Coded-aperture imaging without detector motion can be used to reconstruct three-dimensional radionuclide distributions in the context of nuclear medicine. This approach offers several advantages over the rotating gamma-ray camera systems presently employed in the clinic. These advantages include improved sensitivity, potentially better spatial resolution, and the capability of doing dynamic studies. There are two problems associated with the coded-aperture approach, however. First, the data is "multiplexed", which refers to the fact that many line integrals of the source distribution are combined together and not measured individually, so that information is lost. Second, the number of resolvable detector elements is typically an order of magnitude less than the number of object elements to be reconstructed, so that the reconstruction problem is underdetermined. Consequently, the reconstruction is not unique. By using various types of a priori information in forming the reconstruction, however, it is possible to augment the incomplete data set. Two algorithms are presented to reconstruct objects from their coded-image projections and various types of a priori information. The first, a Monte Carlo algorithm, is a flexible and computationally efficient approach using the a priori knowledge of positivity and nearest-neighbor correlation. This algorithm is used to qualitatively explore the effect of the data-taking geometry on reconstruction performance. The second algorithm is a linear estimator incorporating as a priori knowledge completely general first- and second-order statistical information about the object class to be reconstructed. The linear-estimator formalism also provides a minimum-variance expression for system optimization. This linear algorithm is used to explore the effects of correct and incorrect a priori information on reconstruction performance, and to quantitatively investigate reconstruction quality with respect to data-taking geometry.
27
Hunter, Morris. "The development of a baccalaureate degree program in medical imaging technology". CSUSB ScholarWorks, 1999. https://scholarworks.lib.csusb.edu/etd-project/1857.
Testo completo
28
Ricciardello, Michelle Heidi. "Development of a simple test object for rapid assessment of fluoroscopic imaging systems". Thesis, Queensland University of Technology, 1991. https://eprints.qut.edu.au/36808/1/36808_Ricciardello_1991.pdf.
Testo completoAbstract (sommario):
Performance assessment of fluoroscopic systems is done by different groups using a diversity of test protocols and phantoms. This project aims to use a single standard inex pensive phantom for non-invasive, clinically realistic testing acceptable to all test bodies in NSW: hospital physicists, Public Works department and Radiation Health Services personnel, fluoroscopic manufacturing company engineers, and radiographers. phantom and protocol have been developed to assess overall fluoroscopic image quality for clinical conditions.
Previous image quality protocols used a prescribed setup (70 kVp, 1mm copper) which is not clinically realistic, and not possible on some units. This is especially the case with the increasing use of automatic brightness control (ABC). The proposed test protocol includes 20 cm water in the imaging phantom, allowing ABC setting of the relevant parameters. It has been found that x-ray beam quality and attenuation produced by the previous protocols differs significantly from that with clinical conditions using 20 cm water under ABC.
When used with a range of fluoroscopic units the water phantom was shown to be more diagnostic of image quality performance than copper, using the test protocol. Patient dose rate correlated with image quality results was useful in assessing overall performance.
29
Huang, Wei. "Automatic affine and elastic registration strategies for multi-dimensional medical images". Link to electronic thesis, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-050207-145713/.
Testo completo
30
Chan, Ming-Yuen. "Transfer function design and view selection for angiographic visualization /". View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?COMP%202006%20CHAN.
Testo completo
31
Ghosh, Payel. "Medical Image Segmentation Using a Genetic Algorithm". PDXScholar, 2010. https://pdxscholar.library.pdx.edu/open_access_etds/25.
Testo completoAbstract (sommario):
Advances in medical imaging technology have led to the acquisition of large number of images in different modalities. On some of these images the boundaries of key organs need to be accurately identified for treatment planning and diagnosis. This is typically performed manually by a physician who uses prior knowledge of organ shapes and locations to demarcate the boundaries of organs. Such manual segmentation is subjective, time consuming and prone to inconsistency. Automating this task has been found to be very challenging due to poor tissue contrast and ill-defined organ/tissue boundaries. This dissertation presents a genetic algorithm for combining representations of learned information such as known shapes, regional properties and relative location of objects into a single framework in order to perform automated segmentation. The algorithm has been tested on two different datasets: for segmenting hands on thermographic images and for prostate segmentation on pelvic computed tomography (CT) and magnetic resonance (MR) images. In this dissertation we report the results of segmentation in two dimensions (2D) for thermographic images; and two as well as three dimensions (3D) for pelvic images. We show that combining multiple features for segmentation improves segmentation accuracy as compared with segmentation using single features such as texture or shape alone.
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Khayat, Mario. "An analysis of flow effects in magnetic resonance imaging /". Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=64018.
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Hanvey, Scott Lewis. "Magnetic resonance imaging to improve structural localisation in radiotherapy planning". Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/5117/.
Testo completoAbstract (sommario):
The purpose of this thesis is to develop the role of magnetic resonance imaging (MRI) in the radiotherapy (RT) planning process. This began by assessing a prototype inline three-dimensional distortion correction algorithm. A number of quality assurance tests were conducted using different test objects and the 3D distortion correction algorithm was compared with the standard two-dimensional version available for clinical use on the MRI system. Scanning patients using MRI in the RT position within an immobilisation mask can be problematic, since the multi-channel head coils typically used in diagnostic imaging, are not compatible with the immobilisation mask. To assess the image quality which can be obtained with MR imaging in the RT position, various MRI quality assurance phantoms were positioned within an immobilisation mask and a series of image quality tests were performed on four imaging coils compatible with the immobilisation mask. It was shown that only the 4-channel cardiac coil delivered comparable image quality to a multi-channel head coil. An investigation was performed to demonstrate how MRI patient position protocols influence registration quality in patients with prostate cancer undergoing radical RT. The consequences for target volume definition and dose coverage with RT planning were also assessed. Twenty patients with prostate cancer underwent a computed tomography (CT) scan in the RT position, a diagnostic MRI scan and an MRI scan in the RT position. The CT datasets were independently registered with the two MRI set-ups and the quality of registration was compared. This study demonstrated that registering CT and MR images in the RT position provides a statistically significant improvement in registration quality, target definition and target volume dose coverage for patients with prostate cancer. A similar study was performed on twenty-two patients with oropharyngeal cancer undergoing radical RT. It was shown that when patients with oropharyngeal cancer undergo an MRI in the RT position there are significant improvements in CT-MR image registration, target definition and target volume dose coverage.
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D'Assonville, Gustav Andre. "Factors affecting the acceptance and meaningful use of picture archive and communication systems by referring clinicians in private practice". Thesis, Nelson Mandela Metropolitan University, 2016. http://hdl.handle.net/10948/4688.
Testo completoAbstract (sommario):
A Picture Archive and Communication System (PACS) is a health information technology that facilitates the electronic storage, transmission, presentation and processing of digital medical-imaging datasets. The benefits of PACS have been well-documented. It provides a means to replace traditional film-based workflows and their inherent limitations. Referring clinicians’ acceptance is a critical factor in the overall success of a PACS implementation; and given the financial implications of project failure, research into physician acceptance and meaningful use is crucial. Very few PACS acceptance studies have focused on the referring clinicians, and even less in the context of the private sector. Therefore, the problem that this research aims to address is: There is a lack of understanding on which factors influence PACS acceptance and the meaningful use thereof by referring clinicians in private practice. This explorative study follows an embedded mixed methodology approach in order to meet the research objectives, favouring a qualitative method of inquiry with the support of a quantitative strand. Electronic questionnaires were distributed to private practice referring clinicians to probe the aspects related to PACS acceptance and its meaningful use. The conceptual framework, as devised by Paré and Trudel (2007), was used as a theoretical lens to categorize and discuss the research results in terms of Project, Technological, Organizational and Behavioural factors that affect PACS acceptance and its meaningful use. The findings showed good acceptance rates, which is in line with other research conducted in this field, including research done in the public sector. Technical and Organizational factors were the most prevalent. An extension of the above-mentioned theoretical framework was proposed to assist in maintaining positive results after the project Implementation phase has been completed. This research expands the Information Technology PACS body of knowledge – by identifying both the technical and the non-technical factors that are crucial in private practice referring doctor acceptance and meaningful use. By addressing these factors, institutions can improve the likelihood of PACS project success in private practice settings. Maximising referring doctor acceptance and meaningful use could also give private practices a competitive advantage over their competitors.
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Yu, Hongliang. "Automatic Rigid and Deformable Medical Image Registration". Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050905-100341/.
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Hirsch, Thomas John 1958. "APPLICATION OF ACOUSTIC NUCLEAR MAGNETIC RESONANCE TO MEDICAL IMAGING". Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/276937.
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Choi, Hongsoo. "Fabrication, characterization and modeling of K₃₁ piezoelectric micromachined ultrasonic transducers (pMUTs)". Online access for everyone, 2007. http://www.dissertations.wsu.edu/Dissertations/Fall2007/h_choi_091007.pdf.
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Wang, Zhizhou. "Diffusion tensor field restoration and segmentation". [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0006046.
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Kirkhorn, Tomas. "Continuous ink jet printing of medical images". Lund : Dept. of Electrical Measurements, Lund Institute of Technology, 1993. http://books.google.com/books?id=YiJrAAAAMAAJ.
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Guo, Hongyu. "Diffeomorphic point matching with applications in medical image analysis". [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011645.
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Tillapaugh, Bennet Howd. "Indirect camera calibration in a medical environment /". Online version of thesis, 2008. http://hdl.handle.net/1850/7900.
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Munechika, Stacy Mark 1961. "Applying multiresolution and graph-searching techniques for boundary detection in biomedical images". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277091.
Testo completoAbstract (sommario):
An edge-based segmentation scheme (i.e. boundary detector) for nuclear medicine images has been developed and consists of a multiresolutional Gaussian-based edge detector working in conjunction with a modified version of Nilsson's A* graph-search algorithm. A multiresolution technique of analyzing the edge-signature plot (edge gradient versus resolution scale) allows the edge detector to match an appropriately sized edge operator to the edge structure in order to measure the full extent of the edge and thus gain the best compromise between noise suppression and edge localization. The graph-search algorithm uses the output from the multiresolution edge detector as the primary component in a cost function which is then minimized to obtain the boundary path. The cost function can be adapted to include global information such as boundary curvature, shape, and similarity to prototype to help guide the boundary detection process in the absence of good edge information.
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Tavares, Adriana A. S. "Development of novel radiotracers as tools for imaging the human brain". Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2919/.
Testo completoAbstract (sommario):
Introduction: Brain imaging using single photon emission computed tomography (SPECT) or positron emission tomography (PET) can be used to study the processes underlying neurological and psychiatric disorders. In addition, in vivo brain imaging using SPECT or PET may provide new approaches for drug target identification, pre-clinical testing and occupancy studies, and therefore improve drug discovery. The utility of in vivo brain imaging using SPECT or PET relies on the ability of different radiotracers (typically organic compounds labelled with radionuclides) to bind to a wide variety of targets, including receptors, transporters and enzymes. Therefore the development of novel radiotracers for in vivo brain imaging using SPECT of PET is of vital importance. This thesis is focused on the process of developing novel radiotracers as tools for imaging the human brain, where the radiotracer discovery and development pipeline is discussed and each step prior to clinical trials investigated. Radiotracer discovery: Previously, discovery of novel brain radiotracers has largely relied on simplistic screening tools. Improved selection methods at the early stages of radiotracer discovery and an increased understanding of the relationships between in vitro physicochemical and in vivo radiotracer properties are needed. This thesis investigated if high performance liquid chromatography (HPLC) methodologies could provide criteria for lead candidate selection by comparing HPLC measurements with radiotracer properties in humans. In this study, ten molecules, previously used as radiotracers in humans, were analysed to obtain the following measures: partition coefficient (Log P); permeability (Pm); percentage of plasma protein binding (%PPB); and membrane partition coefficient (Km). Relationships between brain entry measurements (Log P, Pm and %PPB) and in vivo brain percentage injected dose (%ID); and Km and specific binding in vivo (BPND) were investigated. Results showed that HPLC measurements of Pm, %PPB and Km were potentially useful in predicting in vivo performance and hence allow evaluation and ranking of compound libraries for the selection of lead radiotracer candidates at early stages of radiotracer discovery. The HPLC tool developed provides information on in vivo non-specific binding and binding potential that is not possible using conventional screening methods. Another important finding reported in this thesis is that Log P should not be relied on as a predictor of brain entry. The HPLC tool developed, together with competition binding assays, was used to characterise a newly synthesised library of compounds for imaging of the translocator protein (TSPO) in brain using SPECT. Results showed that compound LS 1 was the most likely to succeed within the library investigated, but the high %PPB observed for LS 1 suggested novel compounds with improved %PPB were needed. Thus, a novel library of compounds for imaging of TSPO in brain using SPECT is currently been developed for future testing using the HPLC tool developed here and competition binding assays. Pre-clinical research: radiotracers for imaging the noradrenaline transporter (NAT) in brain using SPECT. In this thesis, NKJ64, a novel iodinated analogue of reboxetine, was successfully radiolabelled via electrophilic iododestannylation and evaluated as a potential SPECT radiotracer for imaging the NAT in brain using rodents and non-human primates. Biological evaluation of the novel radiotracer, 123/125I-NKJ64, in rodents included: in vitro ligand binding assays; in vitro and ex vivo autoradiography; in vivo biodistribution studies and ex vivo pharmacological blocking studies. In rats, 123/125I-NKJ64 displayed saturable binding with nanomolar affinity for the NAT in cortical homogenates, regional distribution consistent with the known density of NAT in the rodent brain and high maximum brain uptake of around 2.93 % of the injected dose. The specific: non-specific ratio (locus coeruleus:caudate putamen) of 123I-NKJ64 uptake was 2.8 at 30 minutes post intravenous injection and prior administration of reboxetine significantly reduced the accumulation of 123I-NKJ64 in the locus coeruleus (> 50% reduction). Data obtained using rodents indicated that further evaluation of 123I-NKJ64 in non-human primates was needed to determine its utility as a SPECT radiotracer for imaging of NAT in brain. Consequently, in vivo kinetic modelling studies using SPECT imaging with 123I-NKJ64 and two baboons were carried out to determine 123I-NKJ64 brain binding kinetics, brain distribution and plasma metabolism in non-human primates. Even though a high brain uptake of around 3.0% of the injected dose was determined, the high non-specific binding observed throughout the brain, a low binding potential (BPND<2) in NAT rich regions and a brain distribution that was inconsistent with the known NAT distribution in non-human primate brain precludes the translation of 123I-NKJ64 into humans. Another NAT radiotracer, 123I-INER, developed by Tamagnan and colleagues at Yale University and Institute for Degenerative Disorders, New Haven, USA, was also investigated as part of this thesis. Kinetic modelling analysis of 123I-INER in baboon brain was investigated for different models, namely invasive and reference tissue models. Bolus plus constant infusion experiments with displacement at equilibrium using six different doses of atomoxetine and four different doses of reboxetine were carried out in several baboons to obtain occupancy measurements as a function of injected dose (mg/kg) for the two NAT selective drugs. Results showed that reference tissue models were able to determine BPND values of 123I-INER in different brain regions. In addition the volume of distribution could be determined by dividing concentration in tissue by the concentration in venous blood at 3 hours post-injection. After administration of atomoxetine or reboxetine, dose-dependent occupancy was observed in brain regions known to contain high densities of NATs. Results supported the translation of 123I-INER into humans studies, despite the slow kinetics determined over the imaging period. Pharmacokinetic properties of 123I-INER described in this thesis may be used to simplify future data acquisition and image processing. Conclusion In conclusion, this thesis reported: (1) the development of novel radiotracers for brain imaging, namely NAT and TSPO; and (2) the development of a new methodology for aiding lead molecule identification at early stages of radiotracer discovery (i.e. prior to radiolabelling). In addition, an overview of radiotracer discovery and development process is provided in a single document, with a focus on brain radiotracers.
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蘇廷弼 e Ting-pat Albert So. "A computerized thermal imaging system for studying thyroid and cerebral cortex". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1994. http://hub.hku.hk/bib/B31233892.
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So, Ting-pat Albert. "A computerized thermal imaging system for studying thyroid and cerebral cortex /". [Hong Kong : University of Hong Kong], 1994. http://sunzi.lib.hku.hk/hkuto/record.jsp?B13829890.
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Abbott, Amanda Helen. "The acquisition and analysis of craniofacial data in three dimensions /". Title page, contents and summary only, 1988. http://web4.library.adelaide.edu.au/theses/09PH/09pha131.pdf.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Dept. of Dentistry, University of Adelaide, 1990.Typescript (Photocopy). A stereo-viewer is provided ... to facilitate fusing of the three dimensional CT reconstructions and the stereo wire frame models--Pref. v. 2. Includes bibliographical references (leaves [244]-263).
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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.
Testo completoAbstract (sommario):
[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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Schomer, Barbara Greene. "Cost effectiveness in telemedicine : conventional versus digital delivery of radiologic images /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Kinkar, Shilpa N. "Development and Application of Semi-automated ITK Tools Development and Application of Semi-automated ITK Tools for the Segmentation of Brain MR Images". Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-050505-103641/.
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Waghorn, Benjamin J. "Monitoring dynamic calcium homeostasis alterations by T₁-weighted and T₁-mapping cardiac manganese enhanced MRI (MEMRI) in a murine myocardial infarction model". Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28237.
Testo completoAbstract (sommario):
Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2009.Committee Chair: Hu, Tom; Committee Co-Chair: Rahnema, Farzad; Committee Member: Wang, Chris; Committee Member: Yanasak, Nathan.