Whilst normal MRI instruments work at a fixed magnetic field, the FFC NMR enables relaxation measurements over a continuous range from the Earth’s magnetic field (~50 mT) of magnetic field strengths up 3T. This corresponds to proton resonance frequencies from 2 kHz to 128 MHz. Such capability has many applications including providing data for the rational development of MRI contrast agents. This will become ever more important as next generation clinical MRIs work at ever higher field strengths – field strengths at which present generation contrast agents perform poorly.