David G. Gadian1, David T. Peat2, Angel J. Perez Linde3, Anthony J. Horsewill2, Walter Kockenberger3, John R. Owers-Bradley2
1UCL Institute of Child Health, London, United Kingdom; 2School of Physics & Astronomy, University of Nottingham, Nottingham, United Kingdom; 3Sir Peter Mansfield MR Centre, School of Physics & Astronomy, University of Nottingham, Nottingham, United Kingdom
We report a series of longitudinal relaxation studies designed to evaluate the effectiveness of certain lanthanides as low temperature relaxation agents. This could be of value in the context of pre-polarizing 13C- or 15N-labelled agents that could then be used, following warming and dissolution, to probe tissue metabolism in vivo. We find that dysprosium-DTPA and holmium-DTPA offer scope for acting as relaxation switches, in the sense of enhancing relaxation at low temperatures without causing undue enhancement of relaxation on returning to room temperature.