Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.664675
Title: Development and application of hyperpolarized krypton-83 as a new MRI contrast agent
Author: Hughes-Riley, Theodore
ISNI:       0000 0004 5364 8812
Awarding Body: University of Nottingham
Current Institution: University of Nottingham
Date of Award: 2014
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Abstract:
Hyperpolarized (hp) gases such 129Xe and 83Kr (spin I = 1/2 and I = 9/2 respectively) can allow for significantly enhanced signal in a number of magnetic resonance applications. As a result there has been a growing interest in recent years to advance hp noble gas technology to non-invasively image the airspace of lungs, with the goal of developing a helpful probe for lung pathologies. 83Kr longitudinal relaxation (T1) has been shown to be sensitive to various surface properties, and may prove to be an interesting for identifying certain diseases including those that change surface chemistry (such as cystic fibrosis) or the surface-to-volume ratio in the lung (like in emphysema). This thesis contains several studies furthering 83Kr lung imaging, while also exploring methods for 129Xe imaging. A major focus has been on increasing spin polarization of the noble gases, as an increased polarization yields a greater MR signal strength. A novel low-pressure spin-exchange optical pumping technique has been utilized in this work allowing for 83Kr polarizations exceeding 17.5 %; as opposed to 4.4 % previously reported in literature. Gas produced in this fashion must be pressurized to above ambient before it is possible for it to be delivered to a lung. Two methodologies for pressurizing the noble gas via compression are explored and optimized for hp gas delivery to excised lungs with 83Kr polarizations as high as 13.8 % achievable after compression. This ultimately allowed for the first ever coronal 83Kr lung images in an ex vivo lung model. Further work repeated with isotopically enriched 83Kr achieved a surface-sensitive T1 relaxation map in this system. Finally gas handling techniques where created to allow for efficient and thorough mixing of the hp noble gases and O2 while minimizing relaxation effects. This is vital for any future in vivo studies.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.664675  DOI: Not available
Keywords: WN Radiology. Diagnostic imaging
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