Dissertations / Theses: 'Imaging and Therapy'

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Heard, Sarah. "Bremsstrahlung Imaging for Radionuclide Therapy." Thesis, Institute of Cancer Research (University Of London), 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487454.

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Beta-emitting radioisotopes such as 90y & 32p do not emit gamma radiation, and so their detection during radionuclide therapies relies on the bremsstrahlung photons released when electrons interact in tissue. The aim of this project was to optimise acquisition parameters (energy window and collimator) for imaging the complex spectra, which are continuous up to relatively high energies, and are of low intensity. Experimental work and theoretical explorations used a combination of list-mode acquisition on an ADAC Forte gamma camera and EGSnrc Monte Carlo simulations. Initially, the camera's energy linearity was investigated and appropriate settings selected for the wide energy range. Photon kernels were developed to approximate beta sources in simulations and were shown to increase speeds significantly. Acquisitions and simulations were then made of a range of phantoms containing 90y or 32p, with low, meditirn and high energy collimation. The data were binned into narrow energy windows, and the resulting images were assessed for vari a tion in qual ity with energy and collima tor, and with parameters such as depth and source-to-background ra tio. Medium energy collimation was found to offer the best compromise between sensitivity and spatial resolution. Image contrast was highest in energy windows near 100 keY, but signal-to-noise ratios (SNR) were highest at lower energies. Wide windows showed improved SNR without significant loss of spatial resolution or contrast. A setting of 60 to 170 keY was selected for the clinic, allowing for practical limits on the camera's window width. The Monte Carlo simulations demonstrated which photon interactions led to these results, for example at which energies septal penetration began to dominate, and how much of the blurring at low energies was due to characteristic x-rays produced in the collimator. The results of this work have been used for initial investigations into the optimisation of analogue imaging with gamma-emitting radioisotopes, for example 111In for 9OY.

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Morin, Kevin Wayne. "Scintigraphic imaging during gene therapy." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq21605.pdf.

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Chen, Ian Ying-Li. "Molecular imaging of cardiac gene therapy /." May be available electronically:, 2008. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.

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Shao, Ning. "Sensing, imaging and photodynamic therapy of cancer." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 73 p, 2007. http://proquest.umi.com/pqdweb?did=1400965061&sid=14&Fmt=2&clientId=8331&RQT=309&VName=PQD.

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Vernooij, Robbin Ralf. "New materials for cancer imaging and therapy." Thesis, University of Warwick, 2017. http://wrap.warwick.ac.uk/102985/.

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Metal-based photoactivated chemotherapy (PACT) involves a class of metal- based prodrugs, which may overcome the limitations and side effects of current metal-based chemotherapeutic agents on account of their novel mechanism(s) of action. In this thesis, a number of vibrational spectroscopic methods were developed and applied to study the mechanisms of metal-based PACT agents upon activation with light. A particularly promising PACT agent is the diazido Pt(IV) anticancer prodrug, trans,trans,trans-[Pt(N3)2(OH)2(py)2] (1, py = pyrdine), in which photoinduced cleavage of ligands from platinum yields reactive species, which are likely implicated with the observed biological activity. However, monitoring the azido and hydroxido ligands, and the metal centre simultaneously remains challenging. Vibrational spectroscopy is a potentially powerful tool to study both metal and ligand vibrations without the requirement of labelling and is non- destructive at the same time. The essential first step was the screening of 1 by a range of vibrational spectroscopic methods, including Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR), Raman and synchrotron radiation far-infrared (SR-FIR), aided by Density Functional Theory (DFT). This yielded an extensive vibrational fingerprint of 1 containing individual ligand (pyridine, hydroxide and azide) and platinum to ligand vibrations. The established methodologies provided the necessary basis for elucidating further photodecomposition and photoreaction pathways. Successive ATR-FTIR studies allowed for examinations of the photodecomposition of 1 complemented by transient electronic absorption and UV-Vis spectroscopy under 420 nm or 310 nm irradiation. Chemometric data evaluation using Principal Component Analysis (PCA) and Multi Curve Resolution Alternating Least Squares (MCR-ALS) on the steady state UV-Vis and ATR-FTIR spectra captured the formation of a Pt(II) intermediate, trans-[Pt(N3)(py)2(OH/H2O)] and a final product, trans-[Pt(py)2(OH/H2O)2], in which the trans pyridine scaffolds were retained. Upon irradiation, the rapid removal of the hydroxido stretching vibration was found to correlate to a shift in the anti-symmetric azido vibration, indicative of a possible second intermediate. Experimental evidence of subsequent azido dissociation from platinum suggests that at least one hydroxyl radical is formed in the reduction of Pt(IV) to Pt(II) under such conditions. Additionally, photoproducts formed upon irradiation of 1 in the presence of the DNA nucleotide 5’-guanosine monophosphate (5’- GMP) could be systematically studied using ATR-FTIR, mass spectrometry and DFT calculations. Underpinning methodologies were subsequently applied to study a series of photoactivatable ruthenium-based CO releasing complexes of the formula [RuLCl2(CO)2] (L = 2,2’-bipyridine with 4’ methyl and/or carboxyl substituents). A three-step mechanism involving the sequential formation of [RuL(CO)(CH3CN)Cl2], [RuL(CH3CN)2Cl2] and [RuL(CH3CN)3Cl]+ was deduced upon 350 nm irradiation in acetonitrile. Rapid removal of the first CO ligand (k1 ≫ 3 min−1 ) and a modest rate for the second CO ligand (k2 = 0.099 – 0.17 min−1 ) was observed, with slowest rates found for the electron-withdrawing carboxyl substituents. Aqueous media considerably slowed down the photodecarbonylation (k1 = 0.46 – 1.3 min−1 and k2 = 0.026 – 0.035 min−1 ) and the carboxyl groups were shown to have a less pronounced effect on the rate constants, revealing the possible implications for the design of such candidates intended for clinical application. State-of-the-art synchrotron based infrared spectroscopy was utilised with continued focus on the mechanism of action of 1. ATR-FTIR and synchrotron radiation far-infrared were combined (SR-ATR-FIR) to enable the rapid screening of samples, exposing changes to the metal to ligand vibrations of 1. Additionally, in situ irradiation using liquid transmission SR-FIR revealed the removal of in the platinum to oxygen (hydroxide) and platinum to nitrogen (azide) vibrations simultaneously. Moreover, a mid-infrared live single cell study of 1 on acute myeloid leukaemia cells (K562) by Synchrotron Radiation Infrared Microspectroscopy revealed significant changes to DNA base stacking and lipid vibrations after only four hours of low dose irradiation at 350 nm (2.58 J cm- 2 ). Lastly, the low wavelength excitation of the earlier described photoactivatable metal-based anticancer prodrug candidates was considered, which commonly hamper their clinical feasibility. A range of lanthanide-doped upconverting nanoparticles (UCNPs) were synthesised, allowing for near-infrared light excitation and visible light emission as a potential platform for wavelength activation of PACT agents in a clinically-relevant window.

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McDannold, Nathan J. "MRI monitoring of high temperature ultrasound therapy /." Thesis, Connect to Dissertations & Theses @ Tufts University, 2002.

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Thesis (Ph.D.)--Tufts University, 2002.
Adviser: David Weaver. Submitted to the Dept. of Physics. Includes bibliographical references (leaves 218-243). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

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Holstensson, Maria. "Quantitative gamma camera imaging for radionuclide therapy dosimetry." Thesis, Institute of Cancer Research (University Of London), 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.533648.

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Gregory, Rebecca Anne. "Quantitative 124I pet imaging for radioiodine therapy disimetry." Thesis, University of London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531335.

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Kharin, Alexander. "Group IV nanoparticles for cell imaging and therapy." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1032/document.

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La biomédecine et la biophotonique sont des champs de recherches en plein expansion qui grandissent à vive allure, constituant un secteur entier d'activités novatrices. Ce secteur, vraiment interdisciplinaire, comprend le développement de nouveaux nanomatériaux, de sources lumineuses et l'élaboration de nouveaux concepts, de dispositifs/équipements pour quantifier la conversion de photons et leurs interactions. L'importance décisive du diagnostic précoce et du traitement individuel des patients exige des thérapies soigneusement ciblées et la capacité de provoquer sélectivement la mort cellulaire des cellules malades. Malgré les progrès spectaculaires réalisés en utilisant les points quantiques ou des molécules biologiques organiques pour l'imagerie biologique et la libération ciblée de médicaments, plusieurs problèmes restent à résoudre : obtenir une sélectivité accrue pour une accumulation spécifique dans les tumeurs et une amélioration de l'efficacité des traitements. D'autres problèmes incluent la cytotoxicité et la génotoxicité, l'élimination lente et la stabilité chimique imparfaite. Des espérances nouvelles sont portées par de nouvelles classes de matériaux inorganiques comme les nanoparticules à base de silicium ou à base de carbone, qui pourraient faire preuves de caractéristiques de stabilité plus prometteuses tant pour le diagnostic médical que pour la thérapie. Pour cette raison, la découverte de nouveaux agents de marquage et de transport de médicaments représente un champ important de la recherche avec un potentiel de croissance renforcé
Biomedicine and biophotonics related businesses are currently growing at a breathtaking pace, thereby comprising one of the fastest growing sectors of innovative economy. This sector is truly interdisciplinary, including, very prominently, the development of novel nanomaterials, light sources, or novel device/equipment concepts to carry out photon conversion or interaction. The great importance of disease diagnosis at a very early stage and of the individual treatment of patients requires a carefully targeted therapy and the ability to induce cell death selectively in diseased cells. Despite the tremendous progress achieved by using quantum dots or organic molecules for bio-imaging and drug delivery, some problems still remain to be solved: increased selectivity for tumor accumulation, and enhancement of treatment efficiency. Other potential problems include cyto- and genotoxicity, slow clearance and low chemical stability. Significant expectations are now related to novel classes of inorganic materials, such as silicon-based or carbon-based nanoparticles, which could exhibit more stable and promising characteristics for both medical diagnostics and therapy. For this reason, new labeling and drug delivery agents for medical application is an important field of research with strongly-growing potential.The 5 types of group IV nanoparticles had been synthesized by various methods. First one is the porous silicon, produced by the electrochemical etching of bulk silicon wafer. That well-known technique gives the material with remarkably bright photoluminescence and the complicated porous structure. The porous silicon particles are the agglomerates of the small silicon crystallites with 3nm size. Second type is 20 nm crystalline silicon particles, produced by the laser ablation of the bulk silicon in water. Those particles have lack of PL under UV excitation, but they can luminesce under 2photon excitation conditions. 3rd type of the particles is the 8 nm nanodiamonds

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Foy, Susan Patricia. "Multifunctional Magnetic Nanoparticles for Cancer Imaging and Therapy." Case Western Reserve University School of Graduate Studies / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=case1319836040.

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Soehnlen, Eric Scott. "Novel Nanomaterials for Tumor Targeted Imaging and Therapy." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1343055033.

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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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Arranja, Alexandra. "Development of copolymer based nanocarriers for imaging and therapy." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE031/document.

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Le développement de nanomédicaments pour l'imagerie et le traitement du cancer a suscité un intérêt croissant à cause de leur grand potentiel. En particulier les vecteurs à base de polymères et de micelles polymères sont très intéressants, car ils peuvent être conçus avec des fonctionnalités adaptées aux besoins.Nous avons utilisé des copolymères amphiphiles triséquencés pour développer de nouveaux nanovecteurs moléculaires (unimères) et supramoléculaires (micelles stabilisées par photo- réticulation). Nous les avons fonctionnalisés avec un marqueur fluorescent ou radioactif pour permettre leur imagerie in vitro et in vivo. Les interactions in vitro et in vivo ont été étudiées pour comprendre l'influence des propriétés des copolymères sur les interactions biologiques.Cette thèse présente le développement complet de nanovecteurs depuis les premières étapes de la caractérisation physico-chimique fondamentale jusqu'à l'évaluation de leur intérêt pour différentes applications cliniques
The interest in developing new nanocarriers for imaging and therapy of cancer has been growing due to their high potential. Particularly nanocarriers based on polymers and polymeric micelles are very interesting because they can be tailor-made with certain functionalities to meet our needs.We have used amphiphilic triblock copolymers to develop new molecular (unimers) and supramolecular (micelles stabilized by photo cross-linking) nanocarriers. The carriers were then functionalized with fluorescent or radioactive markers to enable their in vitro and in vivo imaging. The in vitro and in vivo interactions were then studied to understand the influence of the copolymers properties on the biological interactions.This thesis presents the complete development of the nanocarriers from the early stages of fundamental physicochemical characterization up to the evaluation of their interest for different clinical applications

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Rodriguez-Macias, Wallberg Kenny A. "Artery Wall Imaging and Effects of Postmenopausal Estrogen Therapy." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5722.

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Kolen, Alexander Franciscus. "Elasticity imaging for monitoring thermal ablation therapy in liver." Thesis, Institute of Cancer Research (University Of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.404968.

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Vigor, K. L. "Antibody targeted nanoparticles for imaging and therapy of cancer." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/19904/.

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The central hypothesis for this thesis is that antibody-targeted superparamagnetic iron oxide nanoparticles (SPIONs) can be used for diagnosis and therapy of cancer. The hypothesis is based on the knowledge that firstly, recombinant single chain Fv antibody fragments (scFv) are effective targeting reagents and second, SPIONs can substantially improve the sensitivity of magnetic resonance imaging (MRI). Furthermore, SPIONs can be induced to generate heat when subjected to an alternating magnetic field (AMF). The aim of the thesis was to test the cancer imaging and therapeutic potential scFvfunctionalised nanoparticles by: (1) Generating scFvs reactive with carcinoembryonic antigen (CEA) a cell surface tumour marker. (2) Developing conjugation methods to attach the scFv, in functional form, to SPIONs. (3) Evaluating the cellular interaction (targeting and specificity) of functionalised SPIONs and (4) Measuring the imaging and therapeutic heating effect of the targeted SPIONs. ScFvs reactive to CEA were generated in Pichia pastoris and conjugation chemistries optimised for attachment of purified scFv to SPION surface. Targeting efficacy of the scFv functionalised SPIONs was tested by ELISA, cellular uptake, confocal microscopy and MRI. Results demonstrated unequivocal CEA-specific cellular uptake and CEAspecific MRI, using SPIONs conjugated with Sm3E, a high affinity humanized anti- CEA scFv. Cellular interaction of the Sm3E-SPIONs was found to be influenced by size and surface properties; neutrally charged Sm3E functionalised dextran SPIONs localised preferentially to the outside of the cell membrane, whilst negatively charged Sm3E functionalised PEGylated SPIONs showed evidence of intracellular uptake. The SPIONs were shown to be effective generators of heat when exposed to AMF of 150V, 0.74A and 1MHz. AMF treatment of Sm3E-SPION targeted cells was found to induce expression of the stress protein HSP70 and lead to hyperthermic cell death in vitro. These results indicate that scFv-SPION conjugates have potential for selective tumour imaging and therapy.

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Phillips, Michael. "Identifying response to therapy in longitudinal PET imaging studies." Thesis, King's College London (University of London), 2014. http://kclpure.kcl.ac.uk/portal/en/theses/identifying-response-to-therapy-in-longitudinal-pet-imaging-studies(97fbec41-f7fd-4d39-89b5-3d806159cf1e).html.

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¹⁸F-FDG PET can predict response using both qualitative and quantitative measures. PET Therapy Response Assessor (PETTRA) software was developed to allow users to view and analyse pre- and post- therapy images and compute quantitative measures for predicting response to therapy. Additionally, registration methodology was developed to register pre- and post- therapy PET/CT images. The methodology registers pre- and post- therapy PET/CT scans by registering CT scans using customised rigid and non-rigid registration performed by the Image Registration Toolkit (IRTK). Registration success was assessed using qualitative visual analysis and quantitative landmark analysis on a cohort of 20 lymphoma patients. Landmark analysis results found average misalignment on IRTK of ~10mm for rigid registration and ~6.5mm for non-rigid registration, in comparison with ~40mm with no registration applied. The effect of both rigid and non-rigid registration on transformed images was assessed. While rigid registration transformation caused minimal changes on intensity and tumour volume (<2%), non-rigid transformations caused changes of 11% and 21% respectively. PETTRA software was used to analyse quantitative parameters in 14 patients with mesothelioma and 85 patients with diffuse large B-cell lymphoma (DLBCL). For the 14 patients with mesothelioma, a range of parameters were used to assess response including SUVmax, SUVpeak, tumour volume (TV), total lesion glycolysis (TLG) and intensity volume histogram (IVH) parameters. TV and TLG were obtained using 13 fixed and 9 adapative threshold segmentation methods. Pre-and post- therapy SUVmax, SUVpeak, TV and TLG all showed promise in predicting survival. The comparison between TV and TLG obtained using different segmentation methods was negligible. For the 85 patients with DLBCL, SUVmax, TV and TLG struggled to predict response in patients according to ROC curves.

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Kwiecinski, Wojciech. "Ultrasound cardiac therapy guided by elastography and ultrafast imaging." Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066131/document.

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La fibrillation atriale affecte 2-3% des européens et nord-américains, les tachycardies ventriculaires sont liées à un risque important de mort subite. Les approches minimalement invasives comme l’Ablation par Cathéter Radiofréquence (RFCA) ont révolutionné le traitement de ces maladies, mais le taux de réussite de la RFCA est limité par le manque de techniques d’imagerie pour contrôler cette ablation thermique.Le but de cette thèse est de proposer de nouvelles approches ultrasonores pour des traitements cardiaques minimalement invasifs guidés par échographie.Pour cela nous avons d’abord validé la précision et la viabilité clinique de l’Élastographie par Ondes de Cisaillement (SWE) en tant que modalité d’imagerie quantitative et temps réel pour l’ablation thermique in vivo. Ensuite nous avons implémenté la SWE sur un transducteur intracardiaque et validé la faisabilité d’évaluer l’ablation thermique in vitro et in vivo sur cœur battant de gros animal. Puis nous avons développé un transducteur intracardiaque dual-mode pour effectuer l’ablation et l’imagerie ultrasonores avec les mêmes éléments, sur le même dispositif. Les lésions thermiques induites par Ultrasons Focalisés de Haute Intensité (HIFU) et contrôlées par la SWE ont été réalisées avec succès in vivo dans les oreillettes et les ventricules chez le gros animal. Finalement la SWE a été implémentée sur un dispositif d’imagerie et thérapie ultrasonores transœsophagien et la faisabilité de cette approche a été démontrée in vitro et in vivo. Ces approches originales pourraient conduire à de nouveaux dispositifs cliniques pour des traitements plus sûrs et contrôlés d’un large éventail d’arythmies et maladies cardiaques
Atrial fibrillation (AF) affects 2-3% of the European and North-American population, whereas ventricular tachyarrhythmia (VT) is related to an important risk of sudden death. AF and VT originate from dysfunctional electrical activity in cardiac tissues. Minimally-invasive approaches such as Radio-Frequency Catheter Ablation (RFCA) have revolutionized the treatment of these diseases; however the success rate of RFCA is currently limited by the lack of monitoring techniques to precisely control the extent of thermally ablated tissue.The aim of this thesis is to propose novel ultrasound-based approaches for minimally invasive cardiac ablation under guidance of ultrasound imaging. For this, first, we validated the accuracy and clinical viability of Shear-Wave Elastography (SWE) as a real-time quantitative imaging modality for thermal ablation monitoring in vivo. Second we implemented SWE on an intracardiac transducer and validated the feasibility of evaluating thermal ablation in vitro and in vivo on beating hearts of a large animal model. Third, a dual-mode intracardiac transducer was developed to perform both ultrasound therapy and imaging with the same elements, on the same device. SWE-controlled High-Intensity-Focused-Ultrasound thermal lesions were successfully performed in vivo in the atria and the ventricles of a large animal model. At last, SWE was implemented on a transesophageal ultrasound imaging and therapy device and the feasibility of transesophageal approach was demonstrated in vitro and in vivo. These novel approaches may lead to new clinical devices for a safer and controlled treatment of a wide variety of cardiac arrhythmias and diseases

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Gade, Terence Peter Ferrante. "Integrated imaging of drug delivery : a molecular imaging approach to the optimization of cancer therapy /." Access full-text from WCMC:, 2007. http://proquest.umi.com/pqdweb?did=1432803381&sid=12&Fmt=2&clientId=8424&RQT=309&VName=PQD.

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Bäck, Sven Å J. "Implementation of MRI gel dosimetry in radiation therapy." Malmö : Lund : Malmö University Hospital ; Lund University, 1998. http://catalog.hathitrust.org/api/volumes/oclc/68945079.html.

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Mei, Chang-Sheng. "Accelerated MR Thermometry for High Intensity Focused Ultrasound Therapy." Thesis, Boston College, 2011. http://hdl.handle.net/2345/2425.

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Thesis advisor: Michael Graf
The purpose of this dissertation was to investigate the temporal limit on the ability to measure temperature changes using magnetic resonance imaging (MRI). The limit was examined in experiments using a variety of imaging techniques for MRI-based temperature measurements. We applied these methods for monitoring temperature changes in focused ultrasound (FUS) heating experiments. FUS is an attractive alternative to surgical resection due to its noninvasive character. FUS treatments have been successfully conducted in several clinical applications. MRI and MR thermometry is a natural choice for the guidance of FUS surgeries, given its ability to visualize, monitor, and evaluate the success of treatments. MR thermometry, however, can be a very challenging application, as good resolution is often needed along spatial, temporal as well as temperature axes. These three quantities are strictly related to each other, and normally it is theoretically impossible to simultaneously achieve high resolutions for all axes. In this dissertation, techniques were developed to achieve this at cost of some reduction in spatial coverage. Given that the heated foci produced during thermal therapies are typically much smaller than the anatomy being imaged, much of the imaged field-of-view is not actually being heated and may not require temperature monitoring. By sacrificing some of the in-plane spatial coverage outside the region-of-interest (ROI), significant gains can be obtained in terms of temporal resolution. In the extreme, an ROI can be chosen to be a narrow pencil-like column, and a sampling time for temperature imaging is possible with a temporal resolution of a few milliseconds. MRI-based thermal imaging, which maps temperature-induced changes in the proton resonance frequency, was implemented in two projects. In the first project, three previously described, fast MR imaging techniques were combined in a hybrid method to significantly speed up acquisition compared to the conventional thermometry. Acceleration factors up to 24-fold were obtained, and a temporal resolution as high as 320 milliseconds was achieved. The method was tested in a gel phantom and in bovine muscle samples in FUS heating experiments. The robustness of the hybrid method with respect to the cancellation of the fat signal, which causes temperature errors, and the incorporation of the method into an ultrafast, three dimensional sequence were also investigated. In the second project, a novel MR spectroscopic sequence was investigated for ultrafast one-dimension thermometry. Temperature monitoring was examined during FUS sonications in a gel phantom, SNR performance was evaluated in vivo in a rabbit brain, and feasibility was tested in a human heart. It was shown capable in a FUS heating experiment in a gel phantom of increasing temporal resolution to as high as 53 milliseconds in a three Tesla MRI. The temporal resolution achieved is an order of magnitude faster than any other rapid MR thermometry sequences reported. With this one-dimensional approach, a short sampling time as low as 3.6 milliseconds was theoretically achievable. However, given the SNR that could be achieved and the limited heating induced by FUS in the gel phantom in a few milliseconds, any temperature changes in such a short period were obscured by noise. We have analyzed the conditions whereby a temporal resolution of a few-milliseconds could be obtained
Thesis (PhD) — Boston College, 2011
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Physics

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Nazarenko, Iuliia. "Lanthanide based dendrimers for photodynamic therapy and biological optical imaging." Thesis, Orléans, 2015. http://www.theses.fr/2015ORLE2074.

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La thérapie photodynamique (PDT) est une méthode de lutte contre le cancer basée sur l’utilisation de la lumière et d’un composé sensible à la lumière, appelé photosensibilisateur (PS). Le PS absorbe la lumière et, en présence d’oxygène, engendre la production des dérivés réactifs de l'oxygène (DRO), lesquels sont toxiques et provoquent la régression de la tumeur. La limitation principale des PSs utilisés dans les tests cliniques est leur faible sélectivité envers les tissus cancéreux. Le but principal de ce projet est de créer des agents multifonctionnels combinant sur une même molécule l’activité PDT, la vectorisation et l’imagerie optique proche infrarouge. Dans cette région du spectre optique, les cellules possèdent une faible autofluorescence, et la lumière proche infrarouge pénètre plus profondément dans les tissus biologiques que la lumière visible. Nous proposons ici de modifier une structure dendrimérique de type poly(amidoamine) de génération 3, en tant que plateforme polyvalente. En effet, ce dernier possède trente-deux groupes terminaux qui peuvent être facilement substitués par des PSs. De plus, cette macromolécule peut complexer dans ses cavités jusqu’à 8 cations lanthanides émettant dans le proche infrarouge. Quatre nouveaux ligands dendrimère ont été synthétisés avec différents PSs tels que des dérivés de naphtalimide, d’anthraquinone et de tétraphénylporphyrine. De plus, le naphtalimide a été couplé avec des groupes dérivés de l’acide folique pour assurer la vectorisation envers les tissus cancéreux. Les complexes de lanthanide émettant dans le proche infrarouge ont été préparés pour chaque dendrimère. La caractérisation des performances des différents complexes a été réalisée. La production de DRO et la présence de complexes d’Yb(III) a été démontrée dans les cellules HL60. Les dendrimères modifiés par les groupes anthraquinone et tétraphénylporphyrine en tant que PS, ont montré, dans les cellules vivantes, une émission proche infrarouge lorsqu’ils sont sous la forme de complexe d’Yb(III). Les résultats obtenus montrent que les complexes de lanthanides formés avec des ligands dendrimères peuvent servir comme des agents de PDT et des rapporteurs luminescents proche infrarouge in cellulo
PDT is a cancer treatment that uses the combination of a nontoxic photoactivated molecule (photosensitizer), an appropriate source of light excitation and molecular oxygen to generate reactive oxygen species (ROS) leading to the decrease of size or to the destruction of tumors. However, the PDT efficiency of currently used drugs is limited by the selectivity for the cancer tissue. The main goal of this work is to develop a multifunctional agent which combines a PDT activity, a tumor targeting and near-infrared (NIR) optical imaging. The use of reporters that absorb at low energy is justified by low tissue autofluorescence and high tissue penetration depth in the NIR spectrum window. For this purpose, we have chosen the generation-3 poly(amidoamine) dendrimers as a versatile platform. Such macromolecules can incorporate eight NIR emitting lanthanide ions inside their branches forming species with thirty-two end groups at the periphery that can be substituted by suitable photosensitizers. Four new dendrimer ligands were synthesized with different photosensitizers, such as derivatives of naphthalimide, anthraquinone, and porphyrin. In addition the naphthalimide photosensitizer was functionalized with a targeting molecule, based on folic acid, to induce selectivity of the molecule towards cancer tissues. The corresponding NIR emitting lanthanide complexes were prepared for each dendrimer. Four Yb(III)-dendrimer complexes were characterized for their photophysical and ROS production properties. All complexes demonstrated a ROS production. The dendrimer functionalized with anthraquinone and tetraphenylporphyrin photosensitizers show strong NIR emission in living cells. These new multifunctional Yb(III)-dendrimer complexes have been designed to broaden the current scope of PDT agents and of NIR optical imaging agents

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Sharman, Wesley M. "Novel water-soluble phthalocyanines for photodynamic therapy and nuclear imaging." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape16/PQDD_0012/MQ26615.pdf.

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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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Mirza, Nasiri Nooshin Mirza. "Novel Metal-Containing Nanoparticle Composites for Cancer Therapy and Imaging." Thesis, University of North Texas, 2020. https://digital.library.unt.edu/ark:/67531/metadc1707253/.

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With all the improvements in cancer treatments, multidrug resistance is still the major challenge in treating cancer. Cells can develop multidrug resistance (MDR) during or after treatment, which will render the cancer cells resistant not only to the chemotherapy drug being used but also to many other structurally- and mechanically-different chemotherapeutics. In the first project, the main focus was on development of drug resistant cell lines by selection with taxol. Gene changes in the L1T2 cell line after treatment with Taxol was studied. Treatment of L1T2 cells with taxol leads to changes in the expression of ABC transporter proteins, whereas the combination of Taxol with protease inhibitors leads to increased efficacy via inhibition of P-glycoprotein (P-gp). In the second project, we showed that our innovatively-designed Au-loaded poly(lactide-co-glycolic acid) nanoparticles (GPLGA NPs) are able to cross biological barriers and deliver inside the cells without being recognized by the ABC protein transporter. (We focus specifically on P-gp-mediated drug efflux in a model of HEK cell lines.) The concentration of gold was measured using inductively-coupled plasma/mass spectrometry (ICP-MS) after 6- and 24-hour treatment of GPLGA NPs, which did not show significant increase of gold inside the cells in presence of the P-gp inhibitor valspodar. Cancer cells were treated with the GPLGA NPs for 24 hours and then irradiated 5 minutes at 1Wcm-2 using laser settings at 680 or 808 nm. Heat generation in cancer cells, after internalizing GPLGA NPs and laser irradiation, was significant irrespective of laser wavelength. The plasmomic heating response in this in vitro model can be a step closer to overcome MDR. Finally, for the third and last project represented in this dissertation, the focus was on the design and synthesis of innovative, biodegradable PLGA NPs, encapsulated with the platinum(II)-based non-organometallic/non-cyclometalated phosphorescent complex PTA = [Pt(ptp)2], a brightly phosphorescent complex (ptp = square-planar bis[3,5-bis(2-pyridyl)-1,2,4-triazolato]). Size-tunable, emission-polarized phosphorescent PTA-loaded PLGA NPs were synthesized using a single-emulsion, solvent evaporation technique. Photoluminescence characterization shows that PTA-loaded PLGA NPs exhibit strong and stable orange emission with peak maximum ~ 580 nm. The photoluminescence quantum yield (QY) of the synthesized PTA-PLGA NPs was evaluated at ~55%, which allows recording of images with a much better contrast than that with PTA in organic solvents without the PLGA (QY ~0.5% and ~0 emission polarization) or even that with typical fluorescent organic dyes like rhodamines.

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Tang, Jingjie. "Innovative imaging systems and novel drug candidates for cancer therapy." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4021.

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Le cancer est l'une des principales causes de décès dans le monde et reste une maladie difficile à traiter du fait des difficultés de pronostic, du développement rapide de métastases et de la résistance aux médicaments. Il en résulte une forte demande en méthodologies d'imagerie innovantes pour le diagnostic précoce et précis ainsi qu’en nouveaux agents anticancéreux possédant de nouveaux mécanismes pour surmonter la résistance aux médicaments. Le but de mon projet de recherche de doctorat était donc de contribuer à cet objectif.La première partie de ma thèse de doctorat a porté sur la création de systèmes sensibles et précis d'imagerie pour la détection de tumeurs cancéreuses en utilisant une nanotechnologie novatrice permettant la délivrance des agents d'imagerie spécifiquement dans les lésions tumorales. Nous avons conçu de nouveaux dendrimères amphiphiles pour assurer le transport de différents agents d'imagerie pour les imageries PET/SPECT, par résonance magnétique et par fluorescence optique. Ces systèmes d'imagerie ont été préparés soit par encapsulation de petites sondes d'imagerie à l'intérieur de nanomicelles dendritiques ou par fonctionnalisation de la surface hydrophile ou de la queue hydrophobe du dendrimère. La deuxième partie a eu pour objectif de développer de nouveaux agents anticancéreux possédant nouveaux mécanismes d’action et une meilleure activité antitumorale. A cet effet, nous avons conçu une série de nucléosides arylvinyltriazoles par réaction oxydante de Heck, ce qui nous a permis d'obtenir les composés désirés pourtant difficiles à synthétiser avec un très large éventail de substrats et une stéréosélectivité unique
Cancer is one of the leading causes of death in the world, and remains a difficult disease to treat because of poor prognosis, rapid tumor metastasis and drug resistance. Therefore, innovative imaging modalities for early and precise diagnosis as well as new anticancer drug candidates with novel mechanisms to overcome drug resistance are in high demand. The aim of my PhD research project was to contribute to this goal.The first part of my PhD thesis was focused on establishing sensitive and precise imaging systems for cancer detection using innovative nanotechnology to deliver imaging agents specifically into tumor lesions. We designed and constructed novel amphiphilic dendrimers to carry different imaging agents for PET/SPECT imaging, magnetic resonance imaging and optical fluorescence imaging. These innovative imaging systems were prepared by either encapsulation of small imaging probes within the dendrimer nanomicelles, or functionalization of the dendrimer hydrophilic surface or hydrophobic tail. The second part of my PhD program aimed to develop new anticancer drug candidates with novel mechanisms for better anticancer activity. Therefore, we designed and synthesized a series of challenging arylvinyltriazole nucleosides via the oxidative Heck reaction, which allowed us to obtain the desired compounds with excellent substrate scope and unique stereoselectivity

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Sharman, Wesley Milton. "Novel water-soluble phthalocyanines for photodynamic therapy and nuclear imaging." Mémoire, Sherbrooke : Université de Sherbrooke, 1997. http://savoirs.usherbrooke.ca/handle/11143/3127.

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Frigerio, B. "PSMA-SPECIFIC ANTIBODY FRAGMENTS FOR PROSTATE CANCER IMAGING AND THERAPY." Doctoral thesis, Università degli Studi di Milano, 2013. http://hdl.handle.net/2434/221052.

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In this study we want to evaluate the potentiality of the use of a single chain Fv (scFv) for molecular imaging and therapy of Prostate Cancer. The target of this scFv is the Prostate Specific Membrane Antigen (PSMA), a type II transmembrane protein overexpressed in advances stages of this disease. In the past we have generated the murine antibody D2B recognizing hPSMA, whose diagnostic specificity has been investigated in xenograft murine models by imaging. In order to obtain a smaller protein able to better penetrate the tissues we decided to convert the murine monoclonal antibody D2B into a format like scFv. This format, due to its smaller size, have also the advantage, compare to the entire antibody, to have a faster clearance from the blood. The scFv has been constructed and its functionality has been tested with success on LNCaP cells. Using BIAcore (a technology able to measure the kinetic interaction between two molecules) we showed that the affinity of our scFv is still remarkable despite its monovalent binding. One goal of the present study is the assessment of potential role of this antibody fragment as diagnostic reagent for the development of radiopharmaceuticals for tumor characterization and molecular imaging. A second goal of the project is the production of a completely human antibody fragment against hPSMA in order to develop a reagent more suitable for therapy. We used phage display technology to convert the murine antibody in a human antibody applying guided selection technology which permits to generate an antibody with the specificity and functionality of the starting rodent mAb.

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RACCAGNI, ISABELLA. "PET imaging as a biomarker of tumor response to therapy." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2015. http://hdl.handle.net/10281/76240.

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Le tecniche di imaging molecolare permettono di visualizzare e caratterizzare processi biologici e rivestono un ruolo fondamentale in oncologia, consentendo di identificare marcatori per la diagnosi e la risposta al trattamento. In questo lavoro di tesi è stato valutato il ruolo della PET come possibile marcatore di risposta al trattamento in a) un modello con k-ras oncogenico e b) un modello di glioma, focalizzando l’attenzione sulle alterazioni del metabolismo e l’ipossia. L’incremento della glicolisi e del consumo di glutammina sono associati a mutazioni dell’oncogene ras in diversi tumori. Il disaccoppiamento di tali processi determina una riprogrammazione del metabolismo per supportare l’aumentata proliferazione fornendo un interessante target terapeutico. Scopo dello studio è la valutazione in vivo delle alterazioni metaboliche e della risposta alla terapia nel modello ottenuto mediante inoculo di fibroblasti con k-ras oncogenico (NIH-RAS). A tale scopo gruppi di topi sono stati monitorati longitudinalmente mediante PET-[18F]FDG e [18F]FLT per la valutazione del metabolismo glucidico e della proliferazione cellulare. I tumori sono stati sottoposti ad analisi immunoistochimiche per confermare i dati ottenuti in vivo. Nello stesso modello è stato valutato l’effetto di un inibitore dell’autofagia (Clorochina) e della glutaminasi (BPTES) singolarmente e in combinazione mediante PET-[18F]FDG e [18F]FLT. Gli animali hanno sviluppato in breve tempo tumori glicolitici e caratterizzati da un’omogenea captazione di [18F]FDG e [18F]FLT. Le immagini PET hanno mostrato un aumento della captazione di [18F]FDG nel tempo e un andamento stabile della proliferazione come mostrato dalla costante captazione di [18F]FLT. Clorochina e BPTES in combinazione hanno determinato un rallentamento della crescita tumorale rispetto ai controlli, ma non sono state osservate variazioni nella captazione di [18F]FDG e [18F]FLT. La presenza di vie alternative per la produzione di glutammato e la necessità di dosi più elevate potrebbero spiegare l’assenza di efficacia di questi trattamenti. L’ipossia rappresenta un fenomeno sfavorevole per la progressione tumorale. L’espressione di HIF1α, principale regolatore dell’ipossia, è associata alla resistenza alla terapia in molti tumori, compreso il glioma. Per questo, una migliore comprensione della modulazione dell’attività di HIF1α nel processo di risposta alla terapia è di particolare interesse. Cellule di glioma U251-HRE-mCherry in grado di esprimere l’enzima luciferasi sotto il controllo di HRE (Hypoxia Responsive Element) e mCherry sotto controllo di un promotore costitutivo sono state utilizzate per valutare la modulazione di HIF1α in seguito a trattamento con Temozolomide (TMZ) in vitro e in vivo. La crescita tumorale è stata monitorata in vivo in animali sottoposti ad inoculo intracerebrale tramite bioluminescenza, fluorescenza, RM e PET con [18F]FAZA e [18F]FLT. In seguito, è stato valutato in vivo l’effetto di due diversi regimi di TMZ. Mediante bioluminescenza è stato possibile monitorare la crescita tumorale e identificare aree ipossiche. I dati ottenuti sono stati confermati dalle immagini di fluorescenza e PET-[18F]FAZA. Le analisi ex vivo per Ki67 hanno invece confermato i dati PET-[18F]FLT ed hanno mostrato un’elevata proliferazione cellulare. Entrambi i dosaggi di TMZ hanno determinato una diminuzione dell’attività di HIF1α a tempi precoci. Al contrario, il segnale di fluorescenza e la captazione di [18F]FLT hanno subìto una diminuzione solo a tempi più tardivi. L’attività di HIF1α può essere considerata un marcatore di risposta al TMZ e questo modello un utile strumento per la valutazione in vivo di farmaci per il trattamento del glioma.
Molecular imaging allows the non-invasive visualization and characterization of biological processes. It can be used in oncology to identify biomarkers for the evaluation of tumor progression and response to therapy. In this thesis work, the animal PET was used as potential biomarker of tumor response to therapy focusing on altered metabolism and hypoxia in a) a model of oncogenic k-ras and b) in a model of glioma. Metabolic alterations, such as increased glycolysis and glutamine consumption, are associated with mutations in k-ras gene. The decoupling of glucose and glutamine uptake leads to a reprogramming of their metabolism to support cell proliferation representing a target for cancer therapy. The aim of this study is to investigate metabolic alterations in k-ras transformed fibroblasts (NIH-RAS) in in vivo studies and to assess response to therapy. Animals subcutaneously implanted with NIH-RAS performed [18F]FDG- and [18F]FLT-PET at several time points to evaluate glucose metabolism and cell proliferation, respectively. Tumors were collected and evaluated for different markers by immunohistochemistry (IHC) to confirm in vivo results. In the same model, the efficacy of chloroquine (autophagy blocker) and BPTES (glutaminase inhibitor) alone or in combination was monitored by [18F]FDG- and [18F]FLT-PET before and 48 hours after treatments. All animals developed fast growing and highly glycolytic tumors in few days that appear homogeneous for both [18F]FDG and [18F]FLT uptake. PET imaging showed a significant increase in [18F]FDG uptake while cell proliferation remained stable over time, as depicted by [18F]FLT uptake. IHC analyses confirmed the high aggressiveness of these cells. Chloroquine and BPTES combined treatment slowed down tumor growth only if compared to vehicle, without affecting glucose metabolism or cell proliferation. The presence of alternative pathways for glutamate production and the need of higher doses of treatments may provide explanations to the lack of treatments’ efficacy. Hypoxia is implicated in many aspects of tumor progression and it is involved in the intracellular stabilization of the hypoxia regulator gene HIF-1α. Since the expression of HIF-1α is associated with poor prognosis and therapy resistance in glioblastoma, a better comprehension of its involvement in tumor response to treatment can be of great interest for clinical translation. U251-HRE-mCherry cells expressing Luciferase under control of a Hypoxia Responsive Element (HRE) and mCherry under the control of a constitutive promoter have been used to assess HIF-1α modulation and cell survival after treatment, both in vitro and in vivo. In vivo analyses characterized the model obtained by stereotaxic injection of glioma U251-HRE cells in mice brain. Tumor progression was monitored comparing bioluminescence, fluorescence and PET with [18F]FAZA and [18F]FLT. Afterwards, two regimens of temozolomide (TMZ) were administered starting 21 days after cells injection. TMZ efficacy was monitored by optical and fluorescence imaging, [18F]FLT-PET and MRI. Bioluminescent signals provided information about tumor growth and hypoxia presence, confirmed by both fluorescence acquisition and [18F]FAZA PET. IHC for Ki67 confirmed data obtained by [18F]FLT-PET, showing a high rate of cell proliferation. Both TMZ regimens showed a decrease of HIF-1α-dependent Luciferase activity at early time after TMZ administration. On the contrary, mCherry fluorescence, such as [18F]FLT uptake, decreased only at the end of treatments. HIF-1α activity reduction can be considered a biomarker of tumour response to TMZ and the U251-HRE-mCherry cell model a feasible tool to evaluate HIF-1α activity and treatment effects in in vivo studies.

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Wang, Yu-Feng. "Quantitative imaging biomarkers: Magnetic resonance imaging for the prediction of radiation therapy treatment response in prostate cancer." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29728.

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Recurrence of prostate cancer after primary radiation therapy is not uncommon, and if unmanaged, can result in disease progression. Early detection of localised recurrence enables opportunities for salvage therapies. The current standard of care for monitoring treatment response involves measurement of blood serum prostate specific antigen levels. This method, however, has limited sensitivity and specificity. Quantitative imaging using magnetic resonance imaging has shown potential as a non-invasive method for monitoring treatment response and may provide a means for early detection of local recurrence prior to development of metastases. Measurement uncertainties in the quantitative parameters, however, can impact their reliability in detecting treatment response. This thesis incorporated multi-site data from a longitudinal study of 21 prostate cancer patients who received radiation therapy. Imaging data pre- and post-radiation therapy was co-registered, and the changes were analysed with region-of-interest and voxel-wise measurements to identify candidate features of treatment response. Thresholds to discriminate treatment-related changes from uncertainties due to scanner stability and non-treatment related biological effects were derived from longitudinal phantom studies and in vivo test-retest studies respectively. These thresholds were found to be dependent on tissue type (tumour vs benign) and prostate zone. Candidate features for monitoring treatment response were identified and found to be dependent on timing of imaging, use of hormonal therapy and method of analysis. Future studies will determine the optimal timing of imaging post-treatment to determine likelihood of local recurrence following radiation treatment. The findings presented in this thesis represent the first steps toward developing reliable predictive models for personalisation of treatment response monitoring and early detection of salvageable local recurrence prior to disease progression.

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Whetstone, Paul Andrew. "Bifunctional metal chelates as tools for imaging, therapy and biomolecular study /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.

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32

Östling, Janina. "New Efficient Detector for Radiation Therapy Imaging using Gas Electron Multipliers." Doctoral thesis, Stockholm University, Medical Radiation Physics (together with KI), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-857.

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Currently film is being replaced by electronic detectors for portal imaging in radiation therapy. This development offers obvious advantages such as on-line quality assurance and digital images that can easily be accessed, processed and communicated. In spite of the improvements, the image quality has not been significantly enhanced, partly since the quantum efficiency compared to film is essentially the same, and the new electronic devices also suffer from sensitivity to the harsh radiation environment. In this thesis we propose a third generation electronic portal imaging device with increased quantum efficiency and potentially higher image quality.

Due to the parallel readout capability it is much faster than current devices, providing at least 200 frames per second (fps), and would even allow for a quality assurance and adaptive actions after each accelerator pulse. The new detector is also sensitive over a broader range of energies (10 keV - 50 MeV) and can be used to obtain diagnostic images immediately prior to the treatment without repositioning the patient. The imaging could be in the form of portal imaging or computed tomography. The new detector is based on a sandwich design containing several layers of Gas Electron Multipliers (GEMs) in combination with, or integrated with, perforated converter plates. The charge created by the ionizing radiation is drifted to the bottom of the assembly where a tailored readout system collects and digitizes the charge. The new readout system is further designed in such a way that no sensitive electronics is placed in the radiation beam and the detector is expected to be radiation resistant since it consists mainly of kapton, copper and gas.

A single GEM detector was responding linearly when tested with a 50 MV photon beam at a fluence rate of ~10¹⁰ photons mm^-2 s^-1 during 3-5 μs long pulses, but also with x-ray energies of 10-50 keV at a fluence rate of up to ~10⁸ photons mm^-2 s^-1. The electron transmission of a 100 μm thick Cu plate with an optical transparency of ~46% was found to be ~15.4%, i.e. the effective hole transmission for the electrons was about one third of the hole area. A low effective GEM gain is enough to compensate for the losses in converters of this dimension. A prototype for the dedicated electronic readout system was designed with 50 x 100 pixels at a pitch of 1.27 mm x 1.27 mm. X-ray images were achieved with a single GEM layer and also in a double GEM setup with a converter plate interleaved. To verify the readout speed a Newton pendulum was imaged at a frame rate of 70 fps and alpha particles were imaged in 188 fps. The experimental studies indicates that the existing prototype can be developed as a competitive alternative for imaging in radiation therapy.

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Östling, Janina. "New efficient detector for radiation therapy imaging using gas electron multipliers /." Stockholm : Medical Radiation Physics, Karolinska institutet and Stockholm University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-857.

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Winberg, Karl Johan. "Carborane Derivatives for Nuclide Therapy and Imaging : Synthesis and Radio-labelling." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3561.

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Sarfehnia, Arman. "The use of orthogonal bremsstrahlung beams for imaging in radiation therapy /." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99203.

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Since portal images are created by megavoltage, forward-directed bremsstrahlung beams, their image quality is inferior to that of images produced by kilovoltage beams. In this study, characteristics of orthogonal bremsstrahlung photons produced by megavoltage electron beams were studied and their suitability for radiotherapy imaging was evaluated. Orthogonal bremsstrahlung beams with kilovoltage effective energies can be obtained from megavoltage electrons striking low atomic number targets. A 10 MeV electron beam emerging out of the research port of a Varian Clinac-18 linac was made to strike carbon, aluminum and copper targets. Percentage depth dose and attenuation measurements of forward and orthogonal beams were performed, and experimental results were compared with Monte Carlo-calculated findings. Images of simple contrast objects taken using the orthogonal bremsstrahlung beams showed superior contrast levels in comparison to those produced by the forward beams.

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Mumtaz, Hamid. "Magnetic resonance imaging in the diagnosis and therapy of breast cancer." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401825.

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Kelly, Stephen Gerard. "Ultrasound imaging of synovitis : relationship to pathobiology and response to therapy." Thesis, Queen Mary, University of London, 2014. http://qmro.qmul.ac.uk/xmlui/handle/123456789/9010.

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Ultrasound (US) imaging has made significant progress over the past 20 years in relation to its role in inflammatory arthritis, and in particular, Rheumatoid Arthritis. Modern US machines provide crisp, detailed images of superficial anatomical structures which has facilitated the uptake of US imaging as an important assessment tool within the Rheumatology department. Diagnostic and prognostic information can now assist clinicians decisions with the goal of improving patient treatment and subsequent outcome. In addition, 3D US imaging has recently been suggested as an additional imaging modality with potential benefits in the assessment of in?ammatory arthritis. Recent work has focused on providing a reliable, responsive US joint count which can be assimilated into routine care as well as providing a platform for clinical research. Thus, my first aim was to show that a defined limited US data set, including 2D and 3D imaging, shows acceptable reliability. I demonstrate that both imaging modalities are reliable in terms of reading and image acquisition when restricted to a limited US data set. My second aim, was to demonstrate that a limited US data set is responsive. Using both a physiological and pharmacological trigger, I demonstrate that both 2D and 3D imaging are responsive and that combining US endpoints with DAS28 (Disease Activity Score - 28) increased the effect size and identifies treatment effects early. Despite notable advances in musculoskeletal US research, there is still need for better understanding of the pathophysiological correlates of ultrasound imaging. Therefore my final aim was to examine the relationship of Power Doppler Signal (PDS) and gray-scale synovial thickening with histological features of synovitis at a single joint level and with an extended joint US data set. I Firstly show that the harvesting of synovial tissue, using a minimally invasive US-guided biopsy technique, is safe and well tolerated by patients and that the quality of tissue and RNA extracted is good. Using this tissue collection method, I demonstrate a good correlation of US and histological parameters of synovitis (specifically CD68+ sub-lining macrophages) at a single joint level, in both an early and established RA cohort. This relationship is maintained if the US assessment is extended to a discrete US joint data set. Furthermore, within the knee joint I demonstrated that PDS correlates well with synovial tissue expression of inflammatory mediators of neoangiogenesis and histological assessment of synovial vascular area.

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Arulappu, Appitha. "Integrating c-Met molecular imaging into the optimisation of cancer therapy." Thesis, King's College London (University of London), 2016. https://kclpure.kcl.ac.uk/portal/en/theses/integrating-cmet-molecular-imaging-into-the-optimisation-of-cancer-therapy(286d5820-a909-4223-9a60-5eb49bd3147f).html.

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Basal-like subtypes of breast cancer (BLBC) account for about 15-20% of all breast cancer, affecting younger women (<50 years old) of predominantly African and Hispanic descent [1] with rapid relapse ([2]. c-Met is overexpressed in various solid tumors, lung, breast, ovary, kidney, colon, thyroid, liver, and gastric carcinomas [3]; [4]; [5]; [6]; [7]; [8]; [9]; [10]; [11]; [12]; [13]; [14]. In breast cancer, a higher c-Met expression level is displayed in BLBC in comparison to other intrinsic breast cancer subtypes [15] . In the first part of this thesis, the basal-like breast tumour xenograft mouse model was used to investigate early signs of locoregional recurrence of primary tumour using a 18F radiolabelled c-Met binding peptide, [18F]AH113804. [18F]AH113804 exhibited significantly higher uptake in the tumours (in comparison to mammary fatty tissue) with a target to background (muscle) ratio of approximately 3:1 (p<0.01). In addition to this, [18F]AH113804 was able to detect local tumor recurrence as early as six days after tumour resection [16]. Following publication of this work, I designed an in-house radiolabelled single chain Fv-Fc fusion against human c-Met, which was selected from a phage display library, and labelled with Cy5 dye initially. It was then labelled with the radioisotope 111In that was conjugated with the chelator CHX-A‟‟DTPA for an increase in radiolabelling efficiency. Both the optical and the radiolabelled version of the scFv-Fc were injected into dual tumour-bearing female mice. The tracer‟s uptakes at the c-Met positive tumour (basal-like breast tumour) and in the c-Met negative but ER positive breast adenocarcinoma), were visualised using an optical detector (for the Cy5 labelled tracer) and a gamma camera (using the SPECT tracer). We detect a higher uptake in the c-Met positive basal-like breast tumour in comparison to the c-Met negative control tumours using both versions of the tracer. EGFR expression has been reported in at least 50% of basal-like breast cancers (BLBCs) [17]. Due to the essential role of EGFR in both proliferation and cell survival pathways in breast epithelium and other epithelia, EGFR inhibitors have been used in clinical trials to treat patients with BLBC [18]. Unfortunately, this was shown to be of limited success [19]. There is a need to gain a deeper understanding of EGFR signalling in order to identify potential therapeutic targets. In the third part of this thesis, assays were carried out to investigate further the effect of PTPN11 knockdown on EGFR and c-Met phosphorylation, cell proliferation and E-cadherin level of expression in basal like breast cancer cells. PTPN11 was identified as an EGFR modulator based on the outcome from a high content screen based on FRET sensing of EGFR activity in situ, monitored by fluorescence lifetime imaging (FLIM). Validation of this novel regulator of EGFR activity in BLBC confirmed a significant slowing of the kinetics of EGFR dephosphorylation upon ligand stimulation, as well as c-Met hyperphosphorylation in cells that were depleted of PTPN11 in PTPN11-silenced cells following EGF stimulation.

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39

Fayad, Hadi. "Respiratory motion modeling for use in diagnostic imaging and radiation therapy." Brest, 2011. http://www.theses.fr/2011BRES2058.

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Les déformations associées au mouvement respiratoire sont l’un des paramètres principaux réduisant la sensibilité et la spécificité au niveau thoracique et abdominal. En outre, le mouvement respiratoire diminue la précision dans la fusion d’images acquises en utilisant un système combiné tomographie à émission de positron / tomodensitométrie (TEP/TDM). Les solutions existantes à jour incluent l’acquisition des images TDM et TEP synchronisées avec la respiration. Cependant, les différences entre l'acquisition 4D TEP et 4D TDM, dues aux conditions de respiration différentes pour ces deux modalités, limitent ce processus. De plus, la dose élevée nécessaire à l’acquisition 4D TDM n’est pas justifiable pour tous les patients. Le premier objectif de cette thèse était alors de générer des images dynamiques TDM à partir d’une image TDM de référence et des matrices de déformation obtenues en utilisant un recalage élastique des données 4D TEP non corrigées pour l’atténuation. Une telle approche élimine, d’une part la nécessité d’une acquisition 4D TDM, et assure d’autre part la bonne correspondance entre les images 4D TDM et 4D TEP. En conséquence, le deuxième objectif de cette thèse était de développer et évaluer dans un premier temps des modèles de mouvement respiratoire spécifiques à chaque patient et dans un deuxième temps des modèles génériques du mouvement respiratoire. Ces modèles relient le mouvement interne aux mouvements externes caractérisés par des signaux respiratoires 1D ou des surfaces externes du patient. Finalement, les deux modèles développés ont été validés et appliqués dans le cadre de la correction du mouvement respiratoire et de l’atténuation en TEP et pour la radiothérapie
One of the most important parameters reducing the sensitivity and specificity in the thoracic and abdominal areas is respiratory motion and associated deformations which represent today an important challenge in medical imaging. In addition, respiratory motion reduces accuracy in image fusion from combined positron emission tomography computed tomography (PET/CT) systems. Solutions presented to date include respiratory synchronized PET and CT acquisitions. However, differences between acquired 4D PET and corresponding CT image series have been reported due to differences in respiration conditions during PET and CT acquisitions. In addition, the radiation dose burden resulting from a 4D CT acquisition may not be justifiable for every patient. The first objective of this thesis was to generate dynamic CT images from one reference CT image; based on deformation matrices obtained from the elastic registration of 4D non attenuation corrected PET images. Such an approach eliminates, on one hand the need for the acquisition of dynamic CT, while at the same time ensuring the good matching between CT and PET images. The second objective was to develop and evaluate methods of building patient specific respiratory motion models and at as a second step more developed generic respiratory motion models. These models relate the internal motion to the parameters of an external surrogate signal (PET respiratory signal or patient's surface) that can be acquired during data acquisition and treatment delivery. Finally, the two developed models were validated and used in the PET respiratory motion and attenuation correction and in radiation therapy applications

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40

Sirk, Shannon Julianne. "Engineering and conjugation of cys-diabodies for cancer imaging and therapy." Diss., Restricted to subscribing institutions, 2009. http://proquest.umi.com/pqdweb?did=1872201191&sid=7&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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41

Liu, Jian. "POLYMER MODIFICATION OF FULLERENE FOR PHOTODYNAMIC TUMOR THERAPY AND TUMOR IMAGING." 京都大学 (Kyoto University), 2010. http://hdl.handle.net/2433/120886.

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42

Maitree, Rapeepan, Gloria J. Guzman Perez-Carrillo, Joshua S. Shimony, H. Michael Gach, Anupama Chundury, Michael Roach, H. Harold Li, and Deshan Yang. "Adaptive anatomical preservation optimal denoising for radiation therapy daily MRI." SPIE-SOC PHOTO-OPTICAL INSTRUMENTATION ENGINEERS, 2017. http://hdl.handle.net/10150/626083.

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Low-field magnetic resonance imaging (MRI) has recently been integrated with radiation therapy systems to provide image guidance for daily cancer radiation treatments. The main benefit of the low-field strength is minimal electron return effects. The main disadvantage of low-field strength is increased image noise compared to diagnostic MRIs conducted at 1.5 T or higher. The increased image noise affects both the discernibility of soft tissues and the accuracy of further image processing tasks for both clinical and research applications, such as tumor tracking, feature analysis, image segmentation, and image registration. An innovative method, adaptive anatomical preservation optimal denoising (AAPOD), was developed for optimal image denoising, i. e., to maximally reduce noise while preserving the tissue boundaries. AAPOD employs a series of adaptive nonlocal mean (ANLM) denoising trials with increasing denoising filter strength (i. e., the block similarity filtering parameter in the ANLM algorithm), and then detects the tissue boundary losses on the differences of sequentially denoised images using a zero-crossing edge detection method. The optimal denoising filter strength per voxel is determined by identifying the denoising filter strength value at which boundary losses start to appear around the voxel. The final denoising result is generated by applying the ANLM denoising method with the optimal per-voxel denoising filter strengths. The experimental results demonstrated that AAPOD was capable of reducing noise adaptively and optimally while avoiding tissue boundary losses. AAPOD is useful for improving the quality of MRIs with low-contrast-to-noise ratios and could be applied to other medical imaging modalities, e.g., computed tomography. (C) 2017 Society of Photo-Optical Instrumentation Engineers (SPIE)

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Steyer, Grant J. "IMAGING OF CARDIOVASCULAR CELLULAR THERAPEUTICS WITH A CRYO-IMAGING SYSTEM." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1271182554.

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44

Honarvar, Hadis. "Development of Affibody molecules for radionuclide molecular imaging and therapy of cancer." Doctoral thesis, Uppsala universitet, Medicinsk strålningsvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-298740.

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Affibody molecules are a promising class of scaffold-based targeting proteins for radionuclide-based imaging and therapy of cancer. This thesis work is based on 5 original research articles (papers I-V), which focus on optimization of molecular design of HER2-binding Affibody variants for high contrast imaging of this predictive biomarker as well as development of Affibody molecules suitable for radionuclide-based targeted therapies. Papers I and II were dedicated to evaluation of the influence of the macrocyclic chelator DOTA positioning at N-terminus, in the middle of helix-3 and at C terminus of a synthetic Affibody molecule, ZHER2:S1. These synthetic variants were labelled with different radionuclides i.e. 111In and 68Ga to study also the effect of different labels on their biodistribution properties. In paper III a 2-helix variant, Z342min, was developed using native ligation cyclization to cross-link helices one and two resulting in a stable 2-helix scaffold and characterized in vivo. This study was performed with the aim to obtain structure-properties relationship for development of smaller Affibody molecules. Papers IV and V were devoted to development of therapeutic strategies. In paper IV, a series of peptide based chelators was investigated for labelling of Affibody molecules with 188Re to provide low renal retention. In paper V, a pretargeting approach using peptide nucleic acid was investigated. These studies were performed with the aim to overcome the high renal retention of Affibody molecules when labelled with residualizing therapeutic radionuclides. Otherwise, the particle emitting radiometals could damage the kidneys more than the tumours. The results obtained for anti-HER2 Affibody molecules summarized in this thesis might be of importance for the development of other scaffold protein based targeting agents.

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Price, Ryan Glen. "Toward magnetic resonance only treatment planning| Distortion mitigation and image-guided radiation therapy validation." Thesis, Wayne State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10153444.

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While MR-only treatment planning has shown promise, there are still several well-known challenges that are currently limiting widespread clinical implementation. Firstly, MR images are affected by both patient-induced and system-level geometric distortions that can significantly degrade treatment planning accuracy. In addition, the availability of comprehensive distortion analysis software is currently limited. Also while many groups have been working toward a synthetic CT solution, further study is needed on the implementation of synCTs as the reference datasets for linac-based image-guided radiation therapy (IGRT) to help determine their robustness in an MR-only workflow.

To determine candidate materials for phantom and software development, 1.0 T MR and CT images were acquired of twelve urethane foam samples of various densities and strengths. Samples were precision machined to accommodate 6 mm diameter paintballs used as landmarks. Final material candidates were selected by balancing strength, machinability, weight, and cost. Bore sizes and minimum aperture width resulting from couch position were tabulated from the literature. Bore geometry and couch position were simulated using MATLAB to generate machine-specific models to optimize the phantom build. Previously developed software for distortion characterization was modified for several magnet geometries, compared against previously published 1.0 T results, and integrated into the 3DSlicer application platform.

To evaluate the performance of synthetic CTs in an image guided workflow, magnetic resonance simulation and CT simulation images were acquired of an anthropomorphic skull phantom and 12 patient brain cancer cases. SynCTs were generated using fluid attenuation inversion recovery, ultrashort echo time, and Dixon data sets through a voxel-based weighted summation of 5 tissue classifications. The DRRs were generated from the phantom synCT, and geometric fidelity was assessed relative to CT-generated DRRs through bounding box and landmark analysis. An offline retrospective analysis was conducted to register cone beam CTs to synCTs and CTs using automated rigid registration in the treatment planning system. Planar MV and KV images were rigidly registered to synCT and CT DRRs using an in-house script. Planar and volumetric registration reproducibility was assessed and margin differences were characterized by the van Herk formalism.

Over the sampled FOV, non-negligible residual gradient distortions existed as close as 9.5 cm from isocenter, with a maximum distortion of 7.4mm as close as 23 cm from isocenter. Over 6 months, average gradient distortions were -0.07±1.10 mm and 0.10±1.10 mm in the x and y-directions for the transverse plane, 0.03±0.64 and -0.09±0.70 mm in the sagittal plane, and 0.4±1.16 and 0.04±0.40 mm in the coronal plane. After implementing 3D correction maps, distortions were reduced to < 1 pixel width (1mm) for all voxels up to 25 cm from magnet isocenter.

Bounding box and landmark analysis of phantom synCT DRRs were within 1 mm of CT DRRs. Absolute planar registration shift differences ranged from 0.0 to 0.7 mm for phantom DRRs on all treatment platforms and from 0.0 to 0.4 mm for volumetric registrations. For patient planar registrations, the mean shift differences were 0.4±0.5 mm, 0.0±0.5 mm, and 0.1±0.3 mm for the superior-inferior (S-I), left-right (L-R), and anterior-posterior (A-P) axes, respectively. The mean shift differences in volumetric registrations were 0.6±0.4 mm (range, 0.2 to 1.6 mm), 0.2±0.4 mm, and 0.2±0.3 mm for the S-I, L-R, and A-P axes, respectively. The CT-SIM and synCT derived margins were <0.3mm different.

This work has characterized the inaccuracies related to GNL distortion for a previously uncharacterized MR-SIM system at large FOVs, and established that while distortions are still non-negligible after current vendor corrections are applied, simple post-processing methods can be used to further reduce these distortions to less than 1mm for the entire field of view. Additionally, it was important to not only establish effective corrections, but to establish the previously uncharacterized temporal stability of these corrections. This work also developed methods to improve the accessibility of these distortion characterizations and corrections. We first tested the application of a more readily available 2D phantom as a surrogate for 3D distortion characterization by stepping the table with an integrated batch script file. Later we developed and constructed a large modular distortion phantom using easily obtainable materials, and showed and constructed a large modular distortion phantom using easily obtainable materials, and used it to characterize the distortion on several widely available MR systems. To accompany this phantom, open source software was also developed for easy characterization of system-dependent distortions. Finally, while the dosimetric equivalence of synCT with CT has been well established, it was necessary to characterize any differences that may exist between synCT and CT in an IGRT setting. This work has helped to establish the geometric equivalence of these two modalities, with some caveats that have been discussed at length. (Abstract shortened by ProQuest.)

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46

Twiss, Megan Margaret Jean. "Multimodality approach to predicting response of vestibular schwannomas to radiation therapy." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/3803.

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Despite that most vestibular schwannomas are successfully treated with radiotherapy, current follow-up protocols entail years of serial magnetic resonance imaging (MRI) scans to ensure cessation of growth. This pilot study sought to identify early predictors of radiation treatment response using a non-invasive multi-modality imaging approach. We hypothesized that by combining information acquired from dynamic contrast-enhanced MRI (DCE-MRI), diffusion tensor imaging (DTI), and L-¹¹C-methionine positron emission tomography (MET-PET) treatment response could be identified sooner than the current several year waiting period. This thesis presents the baseline MRI and MET-PET results of the pilot study acquired to-date with follow-up data to be acquired in the next six months. Baseline results suggest that DTI and DCE-MRI yield information that may be useful in identifying the response of vestibular schwannomas to radiotherapy. In particular, vestibular schwannomas display elevated mean diffusion coefficients relative to the contra-lateral cerebellum. Also, the novel use of arterial input functions derived from the anterior inferior cerebellar arteries has led to the successful implementation of DCE-MRI pharmaco-kinetic models which may be used to quantitatively monitor tumor response to radiotherapy. Furthermore, MET-PET has shown promise as a tool for evaluating response as all tumors exhibited enhancement under this modality as compared to the contra-lateral side of the brain. Single-voxel spectroscopy with 3T MRI has proven to be a poor technique with which to examine vestibular schwannomas since only two of eight spectra were acquired successfully. All of the techniques that have shown promise as investigatory tools of tumor response can potentially be implemented clinically in the near future.

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Henderson, Amy 1980. "Motor learning in stroke : imaging training induced plasticity." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=101716.

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Stroke is a leading cause of death and disability in Western countries and it is estimated that up to 70% of stroke survivors have a long-lasting disability of the upper limb. The purpose of this study was to examine plasticity at the neuronal level to distinguish between recovery and compensation and how this relates to recovery of arm movement at the behavioural and functional levels in five chronic stroke patients. Brain activation patterns associated with a pointing movement involving the whole arm were identified over two baselines and one post-training intervention evaluation. At each evaluation, a clinical physical and cognitive evaluation, and a recording of the movement kinematics was performed. Analysis was performed on three regions of interest (ROI) bilaterally; primary motor cortices (M1), premotor cortices (PMC) and the primary sensorimotor cortices (S1). A measure of signal intensity, the location of peak activation, and a measure of the contribution of each hemisphere in the ROIs was examined on a case-by-case basis. We found a trend for increased contralesional involvement, changes in signal strength in each ROI and shifts in the peak activation in many directions, which paralleled increases in motor functioning. Our results seem to suggest that contralesional involvement in our ROIs may be sustaining recovery in these patients, and we can confirm that the more the activation in the stroke brain returns to the activation seen in healthy individuals, the better the recovery. Although it is possible that an absolute distinction between recovery and compensation at the neuronal level cannot be made, our results show that recovery at the behavioural and functional levels are accompanied by changes in brain activity. A relationship must be determined if we are to venture into using fMRI as a tool to influence clinical decisions during recovery from stroke.

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Baillie-Hamilton, Paula. "Applications of magnetic resonance in cancer diagnosis and therapy." Thesis, University of Oxford, 1995. http://ora.ox.ac.uk/objects/uuid:72d25d7c-4f5a-4bc4-9fb0-45f758c09d7b.

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49

Boulos, Paul. "Ultrasound imaging of the ultrasound thrombolysis." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1251/document.

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Les techniques de thérapie par ultrasons sont apparues très récemment avec la découverte des ultrasons de haute intensité focalisée. La thrombolyse ultrasonore extracorporelle en fait partie et se base sur la destruction mécanique du thrombus causée par la cavitation acoustique. Cependant, c'est un phénomène mal contrôlé. Ainsi, un meilleur contrôle de l'activité de cavitation et sa localisation pendant la thérapie est essentiel pour considérer le développement d'un dispositif thérapeutique. Un prototype a déjà été conçu et amélioré avec une boucle de rétroaction en temps réel afin de contrôler l'activité de puissance de cavitation. Cependant, pour surveiller le traitement en temps réel, un système d'imagerie ultrasonore doit être incorporé dans le dispositif thérapeutique. Il doit être capable de localiser le thrombus, de positionner la focale du transducteur thérapeutique, de contrôler la destruction complète du thrombus et d'évaluer en temps réel l'activité de cavitation. Le travail actuel se focalise principalement sur le développement de techniques d'imagerie ultrasonore passive utilisées pour reconstituer les cartographies d'activité de cavitation. Différents algorithmes de formation de voies ont été examinés et validés par des simulations de sources ponctuelles, des expériences in vitro sur fil et des expériences de cavitation dans une cuve d'eau. Il a été démontré que l'algorithme de formation de voie le plus précis pour la localisation du point focale de cavitation est la technique de cartographie passive acoustique pondérée avec le facteur de cohérence de phase (PAM-PCF). En outre, des tests in vivo sur un modèle animal d'ischémie des membres aigus ont été évalués. Enfin, certaines optimisations du système d'imagerie développé précédemment ont été réalisées comme l'imagerie 3D, l'implémentation en temps réel et l'imagerie hybride combinant l'imagerie active anatomique avec les cartographies de cavitation passive
Ultrasound therapy techniques emerged very recently with the discovery of high intensity focused ultrasound (HIFU) technology. Extracorporeal ultrasound thrombolysis is one of these promising innovative low-invasive treatment based on the mechanical destruction of thrombus caused by acoustic cavitation mechanisms. Yet, it is a poorly controlled phenomenon and therefore raises problems of reproducibility that could damage vessel walls. Thus, better control of cavitation activity during the ultrasonic treatment and especially its localization during the therapy is an essential approach to consider the development of a therapeutic device. A prototype has already been designed and improved with a real-time feedback loop in order to control the cavitation power activity. However, to monitor the treatment in real-time, an ultrasound imaging system needs to be incorporated into the therapeutic device. It should be able to first spot the blood clot, to position the focal point of the therapy transducer, control the proper destruction of the thrombus, and evaluate in real-time the cavitation activity. Present work focusses mainly on the development of passive ultrasound techniques used to reconstruct cavitation activity maps. Different beamforming algorithms were investigated and validated through point source simulations, in vitro experiments on a wire, and cavitation experiments in a water tank. It was demonstrated that an accurate beamforming algorithm for focal cavitation point localization is the passive acoustic mapping weighted with the phase coherence factor (PAM-PCF). Additionally, in vivo testing on an animal model of acute limb ischemia was assessed. Finally, some optimizations of the previous developed imaging system were carried out as 3D imaging, real-time implementation, and hybrid imaging combining active anatomical imaging with passive cavitation mapping

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Belmont, Alissa J. "Anticipatory Coarticulation and Stability of Speech in Typically Fluent Speakers and People Who Stutter Across the Lifespan| An Ultrasound Study." Thesis, University of South Florida, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1595349.

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This study uses ultrasound to image onset velar stop consonant articulation in words. By examining tongue body placement, the extent of velar closure variation across vowel contexts provides for the measurement of anticipatory coarticulation while productions within the same vowel context provide measurement of extent of token-to-token variation. Articulate Assistant Advanced 2.0 software was used to semi-automatically generate midsagittal tongue contours at the initial point of maximum velar closure and was used to fit each contour to a curved spline. Patterns of lingual coarticulation and measures of speech motor stability, based on curve-to-curve distance (Zharkova, Hewlett, & Hardcastle, 2011), are investigated to compare the speech of typically fluent speakers to the speech of people who stutter. Anticipatory coarticulation can be interpreted as a quantitative measure indicating the maturity of the speech motor system and its planning abilities. Token-to-token variability is examined from multiple velar vowel productions within the same vowel context, describing the accuracy of control, or stability, of velar closure gestures. Measures for both speaking groups are examined across the lifespan at stages during speech development, maturation, and aging. Results indicate an overall age effect, interpreted as refinement, with increased speech stability and progressively more segmental (less coarticulated) productions across the lifespan. A tendency toward decreased stability and more coarticulated speech was found for younger people who stutter, but this difference was small and absent among older adults. Outcomes of this study suggest the articulatory maturation trajectories of people who stutter may be delayed, but overall maturation of the speech mechanism is evident by older adulthood for typically fluent speakers and those who stutter. Applications to intervention are discussed in closing.

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Dissertations / Theses on the topic 'Imaging and Therapy'

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