Dissertations / Theses on the topic 'X-ray contrast agent'
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Butzer, Jochen Sieghard. "MARS-CT: Biomedical Spectral X-ray Imaging with Medipix." Thesis, University of Canterbury. Physics and Astronomy, 2009. http://hdl.handle.net/10092/3863.
Full textPen, Olga Vladimirovna. "Calculation of the effective atomic number for the iodine contrast agent of the varying concentrations." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/78149.
Full textMaster of Science
ZANARDO, MORENO. "OPTIMISATION OF CONTRAST AGENT ADMINISTRATION FOR CT AND MRI." Doctoral thesis, Università degli Studi di Milano, 2020. http://hdl.handle.net/2434/698794.
Full textWallyn, Justine. "Stealth nanoparticles for preclinical X-rays imaging and multimodal X-rays/MRI (magnetic resonance imaging) imaging." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAF074.
Full textBiomedical imaging is nowadays an essential tool to establish a diagnosis by means of observation of tissues and biological fluids. Combination of imaging instrument with contrast enhancers is a key to obtain clear delineation of a desired tissue by accumulation of a contrast agent into this specific target. The two main imagers are the X-ray scanner and the magnetic resonance imaging (MRI).These imagers are frequently used in conjuncture. Typically, small hydrosoluble iodinated molecules are used as contrasting material for radiography whereas MRI involves magnetic materials like iron oxide nanoparticles. In this work, we proposed two novel contrast agents, the first one was aiming to form an alternative to iodinated contrast agents suffering from fast excretion and causing renal toxicity whereas the second one was aiming at providing bimodal contrasting ability to facilitate access to bimodal imaging procedure in clinics. In the first case, iodinated polymeric nanoparticles, serving for preclinical X-ray imaging were formulated by nanoprecipitation technique. Parameters of formulation were elucidated to provide nanoparticles with size distribution suitable for in vivo administration and high iodine content for contrast enhancement. In vivo study revealed the efficacy of our nanoparticles to clearly visualize liver and spleen and limiting current issues associated with marketed radiopaque contrast agents. The second work achieved was aiming at formulating bimodal lipids-based nanocarriers capable of yielding contrast enhancement for X-ray imaging and MRI by combining iodinated oil and iron oxide nanoparticles within a nano-emulsion core. This would provide bimodal nanoparticulate platform to carry out fast and efficient dual modal imaging procedures. In this context we succeeded to generate efficient dual modal contrast agent yielding clear visualization of liver and kidney by MRI and liver and spleen by X-ray imaging. Pharmacokinetic profile was so determined thanks to bimodal imaging. Using MRI allowed to show that kidneys eliminated a fraction of the dose whereas X-ray imaging confirmed that both tissues, liver and spleen, were passively targeted. These two studies proposed solutions limiting current issues of radiopaque contrast agents and novel formulations to facilitate bimodal imaging for soft tissues imaging
Li, Xiang. "Nano-émulsions radio-opaques iodées pour applications précliniques en imagerie par rayons X." Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAF041/document.
Full textThe X-ray microtomography (called mico-CT, CT = Computed Tomography) is a high-resolution X-ray tomography, uses X-rays to create cross-sections of a 3D-object that later can be used to recreate a virtual model without destroying the original model. The contrast agent is a substance used to enhance the contrast of structures or fluids within the body in medical imaging. The purposes of the thesis were the development of iodine-containing nano-emulsion based contrast for preclinical applications in biomedical imaging. We proposed to study blood pool contrast agents based on iodine-containing nano-emulsions and to develop simpler procedure for the preparation of these iodine-containing nano-emulsions. Three different iodinated oils were synthesized and used as the contrasting part in the nano-emulsions. Finally, nano-emulsions of iodinated α-tocopherol have been enabled us to achieve the purpose of the thesis. These iodinated nano-emulsions demonstrated very good biocompatibility and showed prolonged and significant contrast enhancement in both bloodstream and liver tissues
Brown, Anna Laura. "Bismuth Nanoparticles as Medical X-ray Contrast Agents: Synthesis, Characterization and Applications." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/1523.
Full textSilvestri, A. "DEVELOPMENT OF GOLD BASED NANO-SYSTEMS FOR BIOMEDICAL APPLICATIONS." Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/482617.
Full textHallouard, François. "Formulation de nano-particules iodées comme agents de contraste a longue rémanence vasculaire pour tomodensitométrie." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10307.
Full textThe aim of this thesis is to formulate a blood pool contrast agent for preclinical X-ray imaging application. In collaboration with the galenic laboratory of Strasbourg, this work has allowed to obtain iodinated nano-emulsions produced by spontaneous diffusion of surfactant and nano-particles produced by iodine ”emulsion - solvent diffusion” as blood pool contrast agent. These emulsions and polymer particles present indeed a vascular persistence of several hours, a sufficient contrast to be use in computed tomography (between 170 and 400 HU), the ability to be administered intravenous and stability of several months. Nano-emulsions, including those produced from Lipiodol®, are the most promising as blood pool contrast media by their high radiopacity (475 ± 30 HU) and vascular persistence (T1/2 of 4.1 ± 1.10 h). Iodinated nano-particles of PCL have a lower X-ray attenuation (168 ± 13 HU), but they are known for their control release of the encapsulated substances. Therefore even if inorganic or lipidic contrast agents show a better contrast, they remain attractive for rapid visualization of the co-encapsulated substance distribution in the body. This thesis also introduced several features for understanding the formulation of nano-emulsions obtained by spontaneous diffusion of surfactant and the nano-particles produced by ”emulsion - solvent diffusion.”
Halliwell, Lauren. "Investigation and synthesis of alkyl cyanoacrylates and modification of X-ray contrast agents for incorporation into alkyl cyanoacrylate for use in medical devices." Thesis, University of Warwick, 2013. http://wrap.warwick.ac.uk/57640/.
Full textKilic, Nüzhet Inci. "Graphene Quantum Dots as Fluorescent and Passivation Agents for Multimodal Bioimaging." Thesis, KTH, Tillämpad fysik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298302.
Full textSedan deras upptäckt har nolldimensionella kvantprickar av grafen (kol) uppmärksammats inom biorelaterade applikationer, särskilt för deras optiska egenskaper, kemiska stabilitet och enkelt modifierbara yta. Denna avhandling fokuserar på en grön syntesmetod av kvävedopade grafen-kvantprickar för bimodal bioavbildning med röntgenfluorescens och optisk fluorescens. Både konventionella och mikrovågs-assisterade solvotermiska syntesmetoder användes för att undersöka metodernas effekt på de syntetiserade kvantprickarna. Den mikrovågs-assisterade metoden möjliggjorde syntes av uniforma kvantprickar med exciteringsoberoende egenskaper på grund av mycket kontrollerbara reaktionsförhållanden. Det demonstrerades att den molekylära strukturen hos prekursorerna påverkade de optiska fluorescensegenskaperna hos grafen-kvantprickarna. Genom att välja specifika prekursorer erhölls kvantprickar som emitterar i både blått och rött ljus, motsvarande emissionsmaxima vid 438 respektive 605 nm under excitering vid 390 respektive 585 nm. Amin-funktionaliserade Rh-nanopartiklar valdes som en aktiv kärna för röntgenfluorescens, syntetiserad genom en mikrovågs-assisterad hydrotermisk metod med en specialdesignad sockerligand som reduktionsmedel. Dessa nanopartiklar konjugerades med blåemitterande kvantprickar genom EDC-NHS-behandling. De hybrida nanopartiklarna uppvisade grön emission (520 nm) under 490 nm excitation och ledde till en minskad cytotoxicitet uppmätt genom cellanalys i realtid (RTCA) jämfört med endast Rh-nanopartiklar, vilket framhävde passiveringsrollen som kvantprickarna spelar. Hybridkomplexet utgjorde ett multimodalt kontrastmedel för bioavbildning, vilket demonstrerades med konfokalmikroskopi (in vitro) och fantomexperiment med röntgenfluorescens.
Larsson, Emanuel. "Evaluation of the Dual-Modal usage of contrast agents by means of Synchrotron X-ray Computed Microtomography and Magnetic Resonance Imaging using Macrophages loaded with Barium Sulfate and Gadolinium Nanoparticles for Detection and Monitoring in Animal Disease Models." Doctoral thesis, Linköpings universitet, Molekylär ytfysik och nanovetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-122607.
Full textWharton, John Timothy. "Highly-iodinated fullerene as a contrast agent for X-ray imaging." Thesis, 2002. http://hdl.handle.net/1911/18149.
Full textDunning, Chelsea Amanda Saffron. "Contrast agent imaging using an optimized table-top x-ray fluorescence and photon-counting computed tomography imaging system." Thesis, 2020. http://hdl.handle.net/1828/12308.
Full textGraduate
Dong, Cunhai. "Physical chemical aspects of lanthanide-based nanoparticles: crystal structure, cation exchange, architecture, and ion distribution as well as their utilization as multifunctional nanoparticles." Thesis, 2011. http://hdl.handle.net/1828/3716.
Full textGraduate
Freedman, Jonathan David. "Synthesis and characterization of cationic contrast agents & imaging of articular cartilage using X-ray computed tomography and magnetic resonance." Thesis, 2015. https://hdl.handle.net/2144/13986.
Full textOsteoarthritis (OA) is a painful, chronic, non-inflammatory disease affecting 140 million people worldwide that alters synovial joint structure and function. OA progressively breaks down hyaline cartilage, the hydrated tissue that provides a smooth, nearly frictionless surface and distributes loads applied to articulating joint surfaces. The loss of glycosaminoglycans (GAGs) from the extracellular matrix of cartilage is an early marker of OA. Therefore, imaging methods that quantify the GAG content of cartilage are of interest. This work investigates the synthesis and development of three cationic contrast agents (CAs) for imaging articular cartilage (AC): CA4+, an iodinated small molecule, and tantalum oxide nanoparticles (Ta2O5 NPs) for x-ray Computed Tomography (CT) imaging; and Gadopentetate-dilysine (Gd(DTPA)Lys2), a gadolinium small molecule for Magnetic Resonance (MR) imaging. These cationic contrast agents are attracted to the strong negative fixed charge of extracellular GAG and, therefore, infiltrate cartilage. This work begins with an overview of CT and MR imaging basic principles, current clinical CAs and contrast enhanced imaging of AC. First, the large-scale (50 g) synthesis of CA4+ is described and the partitioning over time of CA4+ into ex vivo AC is correlated to GAG content and cartilage mechanical properties. Similar partitioning studies are applied to anionic, neutral and cationic Ta2O5 NPs, where the cationic NP exhibited substantially greater affinity for AC. Moreover, by maintaining the positive charge on the NP surface and introducing a polyethylene glycol coating, a NP formulation is described for successful in vivo cartilage imaging. Next described is the MRI CA, Gd(DTPA)Lys2, which affords an equivalent T1 signal in cartilage at 1/10th the effective dosage of anionic gadopentetate. Finally, the equilibrium partitioning of the small molecule CT and MRI CAs is directly compared to GAG content and mechanical properties in human finger AC. In summary, results show cationic CAs strongly correlate to both GAG and mechanical properties and distribute in direct proportion to GAG unlike anionic CAs. The use of cationic CAs to quantify the biochemical and mechanical changes of AC may aid drug discovery and improve clinical assessment and intervention of OA for future patients.
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Simard, Mikaël. "Étude de la tomodensitométrie spectrale quantitative et ses applications en radiothérapie." Thesis, 2021. http://hdl.handle.net/1866/25252.
Full textX-ray computed tomography (CT) is an imaging modality that produces a tridimensional map of the attenuation of X-rays by the scanned object. In radiation therapy, CT provides anatomical and quantitative information on the patient that is required for treatment planning. However, CT has some issues, notably (1) a limited accuracy in the estimation of quantitative physical parameters of the patient, and (2) a sensitivity to biases caused by beam hardening artifacts. Finally, (3) in the case where contrast-enhanced CT is performed to help treatment planning, a second scan with no contrast agent is required for dose calculation purposes, which increases the overall dose to the patient. Those 3 problems limit the efficiency of CT for some treatment modalities more sensitive to uncertainties, such as proton therapy. Spectral CT regroups a set of methods that allows the production of multiple X-ray attenuation maps evaluated over various energy windows. The additional energy-weighted information that is obtained allows better material characterization. The potential of one spectral CT modality, dual-energy CT (DECT), is already well demonstrated for radiation therapy, while an upcoming method, spectral photon counting CT (SPCCT), promises more spectral information with the help of energy discriminating detectors. Unfortunately, SPCCT suffers from increased noise and poor conditioning. This thesis thus investigates the following question: is there a benefit to using more, but lower quality energy-resolved information for radiotherapy? The question is studied in the context of the three problems discussed earlier. First, a maximum a posteriori (MAP) estimator is introduced for post-reconstruction tissue characterization for denoising purposes in spectral CT. The estimator is validated experimentally using a commercial DECT. The noise level on the proton stopping power is reduced, on average, by a factor of 3.2 with the MAP estimator. The estimator also generally con- serves the quantitative accuracy of estimated physical parameters. For instance, the stopping power varies on average by 0.9% with respect to the conventional approach. Then, the MAP estimation framework is adapted to the context of contrast-enhanced imaging. Numerical results show clear benefits when using SPCCT for virtual non-contrast imaging compared to DECT, with a reduction of the RMS error on the proton stopping power from 2.7 to 1.4%. Third, the developed tools are validated experimentally on a micro-SPCCT from MARS Bioimaging, which uses the Medipix 3 chip as a photon counting detector. Small benefits in the accuracy of physical parameters of tissue substitutes materials are obtained. Finally, a new parametrization of the attenuation coefficient for pre-reconstruction imaging is pro- posed, whose ultimate aim is to correct beam hardening artifacts. In a simulation study, the proposed parametrization eliminates all biases in the estimated physical parameters of human tissues, which is an improvement upon existing parametrizations. However, no ad- vantage has been obtained with SPCCT compared to DECT, which suggests the need to incorporate MAP estimation in the pre-reconstruction framework using an iterative reconstruction approach.