Tuesday, November 15, 2011

Hot Topics in Spin-Hyperpolarization

Nuclear Magnetic Resonance (NMR) spectroscopy, microscopy and imaging techniques (MRI) play a crucial role in numerous fields of science ranging from physics, chemistry, material sciences, biology to medicine. The high information content of modern multi-dimensional NMR spectroscopy makes it possible to obtain structural and dynamical information with atomic resolution. In addition, owing to the low energy excitation in the MHz frequency region, the method is non-invasive, making it one of the most important imaging modalities in medical diagnostics. However, despite all its versatility, the key issue is frequently sensitivity, which limits the applicability of NMR spectroscopy and imaging techniques in the case of fast dynamical processes and detection of lowly concentrated molecules in both in vitro and in vivo applications.

Several strategies for spin-hyperpolarization are used to increase substantially NMR sensitivity. Two of these strategies are based on the transfer of the much bigger electron spin polarization onto the nuclear spin system either during a chemical reaction (Chemical Induced Dynamic Nuclear Polarization, CIDNP) or by using microwave fields (Dynamic Nuclear Polarization, DNP).Parahydrogen Induced Polarization (PHIP) is based on the correlation between a particular quantum mechanical spin state and a rotational state in diatomic hydrogen. In a chemical reaction the hydrogen spin state can be used to generate target molecules with high spin polarization. In spin exchange optical pumping (SEOP) the polarization of excited electrons is transferred onto noble gas atoms such as Helium, Xenon and Krypton to generate highly polarized gases for MRI application to lung studies, characterization of porous media and surfaces.

Although the hyperpolarization strategies differ in their underlying physico-chemical principles they have a number of problems in common. Recently, a network across Europe and associated states has been launched within the ESF COST programme (Action TD1103) to stimulate the communication between technology developers and users of the different hyperpolarisationtechniques. The Lorentz workshop will provide an overview of the current state-of-the-art in spinhyperpolarisation and aims to identify common problems and mutual points of interest to initiate communication and collaborative projects within the COST Action.