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Gadolinium Concentration Analysis in a Brain Phantom by X-Ray FluorescenceAlmalki, Musaed Alie Othman January 2009 (has links)
The study was conducted to develop a technique that measures the amount of gadolinium based contrast agent accumulated in a head tumour by x-ray fluorescence, while a patient is exposed to neutrons or during external beam radiotherapy planning. In this research, measurements of the gadolinium concentration in a vessel simulating a brain tumour located inside a head phantom, by the x-ray fluorescence method were taken, where the Magnevist contrast medium which has gadolinium atom, in the tumour vessel, was excited by a 36 GBq (0.97 Ci) 241Am source that emits gamma rays of 59.54 keV, in 35.7 % of it’s decays, resulting the emission of characteristic fluorescence of gadolinium at 42.98 keV that appeared in the X-ray fluorescence spectrum. A Cadmium Telluride (CdTe) detector was used to evaluate and make an analysis of the gadolinium concentration. Determinations of the gadolinium content were obtained directly from the detector measurements of XRF from gadolinium in the exposed tumour vessel. The intensity measured by the detector was proportional to the gadolinium concentration in the tumour vessel. These concentrations of gadolinium were evaluated for dose assessment. The positioning of the head phantom was selected to be in the lateral and vertex positions for different sizes of tumour vessels. Spherical tumour vessels of 1.0, 2.0, 3.0 cm and an oval tumour vessel of 2.0 cm diameter and 4.0 cm length, containing the gadolinium agent, contained concentration between 5.62 to 78.63 mg/ml. They were placed at different depths inside a head phantom at different positions in front of the detector and the source for the measurements. These depths ranged from 0.5 cm to 5.5 cm between the center of the tumour and interior wall of the head phantom surface. The total number of measurements in all four sizes of the tumour vessel was 478; 78 examinations of a 1.0 cm spherical tumour vessel, 110 examinations of a 2.0 cm spherical tumour vessel, 150 examinations of a 3.0 cm spherical tumour vessel and 140 examinations of a 2.0 x 4.0 cm ellipsoid tumour vessel. To measure the size and the shape of the tumour by the alternative radiographic method, a general x-ray machine with radiograph film was used. Based on that, the appropriate shape of concentration could be selected for therapy. The differences of optical density in the x-ray films showed that the noise was increased with low concentration of the Gd. Because radiographic film may be subjected to different chemical processes where the darkness will be affected, these measurements would be very hard to be quantitative. Accordingly it is difficult to use the film for Gd concentrations. The obtained data show that the method works very well for such measurements.
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Photophysics of emission color in flourescent proteins /Shu, Xiaokun. January 2007 (has links)
Thesis (Ph. D.)--University of Oregon, 2007. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 176-185). Also available for download via the World Wide Web; free to University of Oregon users.
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Clinical application of QLF and DIAGNOdent : two new methods for quantification of dental caries /Tranæus, Sofia, January 2002 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2002. / Härtill 5 uppsatser.
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Development of yeast-based methods to screen for plant cytokinin-binding proteinsWang, You. January 2004 (has links)
Thesis (M.Sc.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: leaf 115-122.
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865 |
Quantum dot labeling of membrane associated targets : the development of small molecule conjugates to interrogate the serotonin transporter proteinWarnement, Michael Robert. January 1900 (has links)
Thesis (Ph. D. in Chemistry)--Vanderbilt University, Dec. 2008. / Title from title screen. Includes bibliographical references.
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k-Space image correlation spectroscopy theory, verification, and applications /Kolin, David L. January 1900 (has links)
Thesis (Ph.D.). / Written for the Dept. of Chemistry. Title from title page of PDF (viewed 2008/01/12). Includes bibliographical references.
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867 |
Design, synthesis and photophysics of fluorescence "turn-on" conjugated polymer chemosensorsFan, Li-juan. January 2006 (has links)
Thesis (Ph. D.)--State University of New York at Binghamton, Department of Chemistry, 2006. / Includes bibliographical references.
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Fluorescence resonance energy transfer studies of protein interactions /Martin, Sarah Friede. January 2008 (has links)
Thesis (Ph.D.) - University of St Andrews, May 2008.
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869 |
Molecular characterization of type 1 endometrial carcinomas /Levan, Kristina, January 2009 (has links)
Diss. (sammanfattning) Göteborg : Univ. , 2009. / Härtill 4 uppsatser.
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Chlorophyll fluorescence as a measure of cold hardiness and freezing stress in 1 + 1 Douglas-fir seedlings : response to seasonal changes in the nursery /Fisker, Susan E. January 1992 (has links)
Thesis (M.S.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references (leaves 37-42). Also available on the World Wide Web.
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