Thesis--Copenhagen University. / Summary in Danish. Includes bibliographical references (p. 177-190) and index.

Thesis--Copenhagen University. / Summary in Danish. Includes index. Bibliography: p. 177-190.

Bismuth based nanomaterials have recently attracted attention as heavy element X-ray contrast agents because of the high atomic number and predicted biological compatibility of bismuth. Nanoparticle X-ray contrast agents may enable a number of novel medical imaging applications, including blood pool and site-directed imaging. However these hypothetical applications are hindered by lack of suitable synthetic methods for production of imaging agents. This dissertation describes synthesis of a novel class of bismuth nanoparticles that are aqueously stabilized using poly and monosaccharides. These particles are synthesized using highly biologically compatible reagents and are oxidatively stable in water and in moderately basic buffered solutions. Bismuth nanoparticles stabilized by the polysaccharide dextran have a large hydrodynamic radius and a relatively small bismuth nanocrystal core (4% bismuth by volume.) Glucose-capped particles have a much higher ratio of bismuth by volume (>60%), and experimental CT scans of these particle solutions demonstrate higher X-ray contrast versus a current clinically used radiocontrast agent. Additional syntheses of hydrophobic organoamine-capped bismuth nanoparticles by reduction of an iodobismuth cluster, and development of other X-ray contrast materials, such as a radiopaque surgical sponge marker and ink, using bismuth micoparticles produced by a top-down ball milling method, are also described.

Ioversol and Iomeprol are radiological contrast media commonly used interchangeably in many South African imaging facilities for coronary angiography. Despite differences in chemical composition, they are presumed to have similar renal safety profiles. However, no studies directly compare the renal safety of these two contrast media for coronary angiography in a predominantly healthy population. A systematic review was performed to establish which contrast medium is safer. Articles were sourced from Medline, CINAHL, Scopus, Science Direct, and PubMed Clinical Queries databases. Eligible studies were peer-reviewed articles of coronary angiography examinations carried out on a healthy adult population, where Ioversol or Iomeprol or both were administered, with contrast-induced nephropathy as an end-point. Six articles with a total population of 2431 patients were selected. The Cochrane Risk of Bias Tool was used in evaluating included articles. Pooling studies using the random effects model did not show a statistically significant reduction in contrast-induced nephropathy when Iomeprol was administered (Risk ratio 1.14, 95% confidence interval 0.797-1.643, p = 0.466). Moderate heterogeneity (I2=54.21%) across the studies was observed. Study limitations included potential bias during data extraction because this was performed by a single reviewer, and language restrictions to include only English titles. Iomeprol may be better for use in the clinical setting because of more a predictable renal safety profile. / Health Studies / M. P. H. (Health Studies)

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