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Fluorine nuclear relaxation times in chelates with lanthanides
Bobrova, Yulia ; Římal, Václav (advisor) ; Wagnerová, Dita (referee)
Contrast agents containing fluorine have great prospects for magnetic resonance imaging in medicine. Low representation of fluorine in human body and the suitable magnetic properties of its nucleus 19 F, provide great sensitivity. The slow relaxation of 19 F, can be shortened by using paramagnetic complexes.In this thesis, transversal and longitudinal 19 F relaxation times of chelates with different paramagnetic lanthanides (Ce, Yb,Tm, Dy, Ho) were measured in two different magnetic fields: 4,7 and 11,7 T. Their values meet the expected assumptions. Furthermore, the values are compared with Bloch-Redfield- Wangsness theory.While Ho, Tm, and Dy reduce fluorine nuclear relaxation times to milliseconds, which is too short for MRI, relaxation rates of Ce a Yb reach approximately 100ms. Such relaxation rates can be considered as optimal for imaging methods. On the basis of our results it is possible to find suitable candidates for fluorine contrast media and optimize the measurement sequence settings in further research or in clinical use.
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