PHIPSPIN · Towards long-lived hyperpolarized spin-state

Currently the relatively low sensitivity of magnetic resonance is a main obstacle, which prevents the Magnetic Resonance Imaging (MRI) detection of molecules with low physiological concentration, as for example molecules related to neurodegenerative diseases like Alzheimer or Parkinson. Due to this there are currently worldwide attempts to increase the sensitivity by hyper-polarization techniques. One of these attempts is the usage of the Para Hydrogen Induced Polarization (PHIP) technique, which can cause four orders of magnitude of increase in the sensitivity of MRI. Although the basic feasibility of this approach has been demonstrated the relatively fast decay of the increased signal prevents until now the in-vivo application. In our project we want to solve this problem and develop novel concepts for slowing down the relaxation processes of the created hyperpolarized spin-state. If this problem is solved, hyperpolarized contrast agents with long signal persistence may open new pathways for scientific or commercial application of the PHIP technique in human MRI. My project concentrates on how the molecular structure and the physical state of the sample affect the life-time of the hyperpolarized state. In particular the question is raised to what extend the isotopical composition of the molecule affects the relaxation time of the hyperpolarized spin-state in solids and liquids by studying PHIP-hyperpolarization of fully or partly deuterated molecular models and whether it is possible to conserve the hyperpolarization by freezing the reactant solution. To answers these questions a detailed investigation of the relevant relaxation mechanisms operating in liquid and solid hyperpolarized samples are planned. The knowledge of these mechanisms can be employed as a guideline for designing long life-time target molecules for the hydrogenation which are applicable as magnetic markers in MRI.