In the recent years, Dynamic Nuclear Polarization (DNP) has emerged as a very promising technique for enhancing the sensitivity of the magnetic resonance spectroscopy and imaging (MRSI). A number of nuclei, namely 13C, 15N, 29Si, 89Y, and 129Xe, have been successfully polarized and a few of them have been employed in the in-vivo studies for functional imaging and metabolism. Hyperpolarized 13C-labeled compounds have wide applications in the metabolic and perfusion studies and can be used for early stage disease diagnosis, response to treatment, prognosis etc. DNP has been demonstrated in the 31P nucleus in nucleotides triphosphates as an application for the structural analysis and identification techniques. In this work, 31P DNP has been successfully applied, optimized and demonstrated in Dimethyl Methyl Phosphonate (DMMP) for the first time. DMMP is a freely diffusible tracer and hyperpolarized DMMP can potentially be used in the perfusion studies using MR imaging and spectroscopic techniques. The polarization buildup and signal enhancements were optimized for two different radicals, a nitroxyl radical TEMPO and a trityl radical OX063. Microwave frequency sweeps were done for both the radicals to find out the optimum frequencies for maximum polarization, Maximum signal enhancement (¡Ö2300 folds) and maximum percent polarization buildup (2.15%) were achieved by polarizing DMMP with the radical OX063 at the microwave frequency of 94.080 GHz with a glassing matrix containing D2O and glycerol and by using D2O in the dissolution step. DMMP was hyperpolarized at the optimum conditions and injected in a mouse for in-vivo spectroscopy and imaging. The results show that hyperpolarized DMMP is a potential candidate for functional imaging and metabolism.
| Identifer | oai:union.ndltd.org:USF/oai:scholarcommons.usf.edu:etd-6536 |
| Date | 07 July 2014 |
| Creators | Afzal, Roha |
| Publisher | Scholar Commons |
| Source Sets | University of South Flordia |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Graduate Theses and Dissertations |
| Rights | default |
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