%0 Journal Article %J Review of Scientific Instruments %D 2007 %T Multipole shimming of permanent magnets using harmonic corrector rings %A Jachmann, R. C. %A Trease, D. R. %A Bouchard, L. S. %A Sakellariou, D. %A Martin, R. W. %A Schlueter, R. D. %A Budinger, T. F. %A Pines, A. %K field %X

Shimming systems are required to provide sufficient field homogeneity for high resolution nuclear magnetic resonance (NMR). In certain specialized applications, such as rotating-field NMR and mobile ex situ NMR, permanent magnet-based shimming systems can provide considerable advantages. We present a simple two-dimensional shimming method based on harmonic corrector rings which can provide arbitrary multipole order shimming corrections. Results demonstrate, for example, that quadrupolar order shimming improves the linewidth by up to an order of magnitude. An additional order of magnitude reduction is in principle achievable by utilizing this shimming method for z-gradient correction and higher order xy gradients. (c) 2007 American Institute of Physics.

%B Review of Scientific Instruments %V 78 %8 Mar %@ 0034-6748 %G English %U ://WOS:000245320800056 %N 3 %M WOS:000245320800056 %! Multipole shimming of permanent magnets using harmonic corrector rings %R Doi 10.1063/1.2713438 %0 Journal Article %J Journal of Magnetic Resonance %D 2004 %T High-resolution NMR of static samples by rotation of the magnetic field %A Meriles, C. A. %A Sakellariou, D. %A Moule, A. %A Goldman, M. %A Budinger, T. F. %A Pines, A. %K hz %X

Mechanical rotation of a sample at 54.7degrees with respect to the static magnetic field, so-called magic-angle spinning (MAS), is currently a routine procedure in nuclear magnetic resonance (NMR). The technique enhances the spectral resolution by averaging away anisotropic spin interactions thereby producing isotropic-like spectra with resolved chemical shifts and scalar Couplings. It should be possible to induce similar effects in a static sample if the direction of the magnetic field is varied, e.g., magic-angle rotation of the B-0 field (B-0-MAS). Here, this principle is experimentally demonstrated in a static sample of solid hyperpolarized xenon at similar to3.4mT. By extension to moderately high fields, it is possible to foresee interesting applications in situations where physical manipulation of the sample is inconvenient or impossible. Such situations are expected to arise in many cases from materials to biomedicine and are particularly relevant to the novel approach of ex situ NMR spectroscopy and imaging. (C) 2004 Elsevier Inc. All rights reserved.

%B Journal of Magnetic Resonance %V 169 %P 13-18 %8 Jul %@ 1090-7807 %G English %U ://WOS:000222161900002 %N 1 %M WOS:000222161900002 %! High-resolution NMR of static samples by rotation of the magnetic field %R Doi 10.1016/J.Jmr.2004.03.023 %0 Journal Article %J Proceedings of the National Academy of Sciences of the United States of America %D 1997 %T In vivo NMR and MRI using injection delivery of laser-polarized xenon %A Goodson, B. M. %A Song, Y. Q. %A Taylor, R. E. %A Schepkin, V. D. %A Brennan, K. M. %A Chingas, G. C. %A Budinger, T. F. %A Navon, G. %A Pines, A. %K humans %X

Because xenon NMR is highly sensitive to the local environment, laser-polarized xenon could be a unique probe of living tissues. Realization of clinical and medical science applications beyond lung airspace imaging requires methods of efficient delivery of laser-polarized xenon to tissues, because of the short spin-lattice relaxation times and relatively low concentrations of xenon attainable in the body. Preliminary results from the application of a polarized xenon injection technique for in vivo Xe-129 NMR/MRI are extrapolated along with a simple model of xenon transit to show that the peak local concentration of polarized xenon delivered to tissues by injection may exceed that delivered by respiration by severalfold.

%B Proceedings of the National Academy of Sciences of the United States of America %V 94 %P 14725-14729 %8 Dec 23 %@ 0027-8424 %G English %U ://WOS:000071182800090 %N 26 %M WOS:000071182800090 %! In vivo NMR and MRI using injection delivery of laser-polarized xenon %R Doi 10.1073/Pnas.94.26.14725 %0 Journal Article %J Proceedings of the National Academy of Sciences of the United States of America %D 1996 %T NMR of laser-polarized xenon in human blood %A Bifone, A. %A Song, Y. Q. %A Seydoux, R. %A Taylor, R. E. %A Goodson, B. M. %A Pietrass, T. %A Budinger, T. F. %A Navon, G. %A Pines, A. %K gas %X

By means of optical pumping with laser light it is possible to enhance the nuclear spin polarization of gaseous xenon by four to five orders of magnitude, The enhanced polarization has allowed advances in nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI), including polarization transfer to molecules and imaging of lungs and other void spaces, A critical issue for such applications is the delivery of xenon to the sample while maintaining the polarization, Described herein is an efficient method for the introduction of laser-polarized xenon into systems of biological and medical interest for the purpose of obtaining highly enhanced NMR/MRI signals. Using this method, we have made the first observation of the time-resolved process of xenon penetrating the red blood cells in fresh human blood-the xenon residence time constant in the red blood cells was measured to be 20.4+/-2 ms. The potential of certain biologically compatible solvents for delivery of laser-polarized xenon to tissues for NMR/MRI is discussed in light of their respective relaxation and partitioning properties.

%B Proceedings of the National Academy of Sciences of the United States of America %V 93 %P 12932-12936 %8 Nov 12 %@ 0027-8424 %G English %U ://WOS:A1996VT05400048 %N 23 %M WOS:A1996VT05400048 %! NMR of laser-polarized xenon in human blood %R Doi 10.1073/Pnas.93.23.12932