The Walsworth Group

Harvard-Smithsonian Center for Astrophysics
Harvard University Department of Physics

Novel Approaches to NMR and MRI

We have a long-standing focus on the development of novel approaches to NMR and MRI, as well as application of these techniques in both the physical and life sciences.  Our current research activities include the development of an open-access, low-magnetic-field human MRI instrument, and its application to studies of: (i) traumatic brain injury (TBI); (ii) molecular imaging using hyperpolarized nanoparticles and other media created by dynamic nuclear polarization (DNP); and (iii) pulmonary physiology using inhaled hyperpolarized noble gas (³He and ¹²⁹Xe).  We are also investigating the creation and application of novel spin states in biomolecules, such as long-lived nuclear spin singlet states and coherences between singlet and triplet states.

Our NMR and MRI investigations are performed in the Walsworth Lab at the Center for Astrophysics and the Low-Field Imaging (LFI) Lab at the Martinos Center for Biomedical Imaging.

 

References

• Dependence of nuclear spin singlet lifetimes on RF spin-locking power. S. J. DeVience, R. L. Walsworth, M. S. Rosen. Journal of Magnetic Resonance 218, 5 (2012). arxiv:1201.1482.
  • Supplementary material for the above article.
• Silicon Nanoparticles as Hyperpolarized Magnetic Resonance Imaging Agents. J.W. Aptekar, M.C. Cassidy, A.C. Johnson, R.A. Barton, M.Y. Lee, A.C. Ogier, C. Vo, M.N. Anahtar, Y. Ren, S.N. Bhatia, C. Ramanathan, D.G. Cory, A.L. Hill, R.W. Mair, M.S. Rosen, R.L. Walsworth and C.M. Marcus. ACS Nano. 3 12, 4003-4008 (2009).
  • Supporting material for the above ACS Nano Silicon Nanoparticle aticle. 
• Harvard Catalyst funds LFI. The LFI move to Martinos was featured in an article about Harvard Catalyst that appeared in the Harvard Medical School Dean's annual report.
• Towards Posture-Dependent Human Pulmonary Oxygen Mapping using Hyperpolarized Helium and an Open-Access MRI System. R.W. Mair, L.L. Tsai, C-H. Li, M.J. Barlow, R.N. Scheidegger, M.S. Rosen, S. Patz and R.L. Walsworth. "Magnetic Resonance Microscopy: Spatially Resolved NMR Techniques and Applications, Proc. 2007 International Conference on Magnetic Resonance Microscopy", (WILEY-VCH Verlag GmbH & Co, Weinheim, 2009), p. 117-127.
• An Open-Access, Very-Low-Field MRI System for Posture-Dependent ³He Human Lung Imaging. L. L. Tsai, R.W. Mair, M.S. Rosen, S. Patz and R.L. Walsworth. Journal of Magnetic Resonance, 193, 274-285 (2008).
• Posture-Dependent Human ³He Lung Imaging in an Open Access MRI System: Initial Results. L. L. Tsai, R.W. Mair, C.H. Li, M.S. Rosen, S. Patz and R.L. Walsworth. Academic Radiology, 15, 728-739 (2008). physics/0707.3455.
• NMR measurements of grain and gas motion in a gas-fluidized granular bed. D. Candela, C. Huan, K. Facto, R. Wang, R.W. Mair and R.L. Walsworth. Granular Matter, 9, 331-335 (2007). cond-mat/0510611.
• Noninvasive measurements of gas exchange in a three-dimensional fluidized bed using hyperpolarized ¹²⁹Xe NMR. T. Pavlin, R. Wang, R. McGorty, M.S. Rosen, D.G. Cory, D. Candela, R.W. Mair and R.L. Walsworth. Applied Magnetic Resonance, 32, 93-112 (2007). cond-mat/0605436.
• Understanding the breakdown of Fourier’s law in granular fluids. D. Candela and R.L. Walsworth. American Journal of Physics, 75, 754-757 (2007). cond-mat/0510295.
• Development of a Low-Field ³He MRI System to Study Posture-Dependence of Pulmonary Function. Leo L. Tsai, PhD thesis (Harvard).
• A System for Open-Access ³He Human Lung Imaging at Very Low Field. I.C. Ruset, L.L. Tsai, R.W. Mair, S. Patz, M.I. Hrovat, M.S. Rosen, I. Muradian, J. Ng, G.P. Topulos, J.P. Butler, R.L. Walsworth and F.W. Hersman. Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering, 29B, 210-221 (2006).
• ³He Lung Imaging in an Open Access, Very-Low-Field Human MRI System. R.W. Mair, M.I. Hrovat, S. Patz, M.S. Rosen, I.C. Ruset, G.P. Topulos, L.L. Tsai, J.P. Butler, F.W. Hersman and R.L. Walsworth. Magnetic Resonance in Medicine, 53, 745-749 (2005). physics/0403090.
• Study of Gas-Fluidization Dynamics with Laser-Polarized ¹²⁹Xe. R. Wang, M.S. Rosen, D. Candela, R.W. Mair and R. L. Walsworth. Magnetic Resonance Imaging, 23, 203-207 (2005). cond-mat/0407708.
• Xenon NMR Measurements of Permeability and Tortuosity in Reservoir Rocks. R. Wang, T. Pavlin, M.S. Rosen, R.W. Mair, D.G. Cory and R. L. Walsworth. Magnetic Resonance Imaging, 23, 329-331 (2005). cond-mat/0407710.
• Simultaneous Measurement of Rock Permeability and Effective Porosity using Laser-Polarized Noble Gas NMR. R. Wang, R.W. Mair, M.S. Rosen, D.G. Cory, and R.L. Walsworth. Physical Review E, 70, 026312 (2004). cond-mat/0312543.
• NMR Experiments on a Three-Dimensional Vibrofluidized Granular Medium. C. Huan, X. Yang, D. Candela, R.W. Mair, and R.L. Walsworth. Physical Review E, 69, 041302 (2004). cond-mat/0305267.
• Applications of Controlled-Flow Laser-Polarized Xenon Gas to Porous and Granular Media Study. R.W. Mair, R. Wang, M.S. Rosen, D. Candela, D.G. Cory, and R.L. Walsworth. Magnetic Resonance Imaging 21, 287 (2003). cond-mat/0211180.
• Diffusion NMR Methods Applied to Xenon Gas for Materials Study. R.W. Mair, M.S. Rosen, R. Wang, D.G. Cory, and R.L. Walsworth. Magnetic Resonance in Chemistry, 40, S29 (2002). cond-mat/0211179.
• The Narrow Pulse Approximation and Long Length Scale Determination in Xenon Gas Diffusion NMR Studies of Model Porous Media. R.W. Mair, P.N. Sen, M.D. Hürlimann, S. Patz, D.G. Cory, and R.L. Walsworth. Journal of Magnetic Resonance 156, 202(2002). cond-mat/0211182.
• Novel MRI Applications of Laser-Polarized Noble Gases. R.W. Mair and R.L. Walsworth. Applied Magnetic Resonance 22, 159 (2002).
• Measuring surface-area-to-volume ratios in soft porous materials using laser-polarized xenon interphase exchange NMR. J.P. Butler, R.W. Mair, S. Patz, D. Hoffmann, M.I. Hrovat, R.A. Rogers, G.P. Topulos, and R.L. Walsworth. Journal of Physics: Condensed Matter 14, L297 (2002). cond-mat/0108344.
• Measurements of Grain Motion in a Dense, Three Dimensional Granular Fluid. X. Yang, C. Huan, D. Candela, R.W. Mair, and R.L. Walsworth. Physical Review Letters 88, 044301(2002). cond-mat/0108256.
• Tortuosity Measurement and the Effects of Finite Pulse Widths on Xenon Gas Diffusion NMR Studies of Porous Media. R.W. Mair, M.D. Hürlimann, P.N. Sen, L.M. Schwartz, S. Patz, and R.L. Walsworth. Magnetic Resonance Imaging 19, 345 (2001). cond-mat/0211184.
• Nuclear Magnetic Resonance Experiments using Laser-Polarized Noble Gas. Glenn P. Wong, PhD thesis (Harvard University).
• Reduced xenon diffusion for quantitative lung study - the role of SF₆. R.W. Mair, D. Hoffmann, S.A. Sheth, G.P. Wong, J.P. Butler, S. Patz, G.P. Topulos, and R.L. Walsworth. NMR in Biomedicine 13, 229 (2000).
• Magnetic resonance imaging of convection in laser-polarized xenon. R.W. Mair, C.H. Tseng, G.P. Wong, D.G. Cory, and R.L. Walsworth. Physical Review E 61, 2741 (2000).
• Biomedical Applications of Low Field MRI in Microgravity. J.P. Butler and R.L. Walsworth. European Radiology 9, B30 (1999).
• A system for low field imaging of laser-polarized noble gas. G.P. Wong, C.H. Tseng, V.R. Pomeroy, R.W. Mair, D.P. Hinton, D. Hoffmann, R.E. Stoner, F.W. Hersman, D.G. Cory, and R.L. Walsworth. Journal of Magnetic Resonance 141, 217 (1999).
• Probing porous media with gas diffusion NMR. R.W. Mair, G.P. Wong, D. Hoffmann, M.D. Hurlimann, S. Patz, L.M. Schwartz, and R.L. Walsworth. Physical Review Letters 83, 3324 (1999).
• Magnetic resonance imaging of laser polarized liquid xenon. C.H. Tseng, R.W. Mair, G.P. Wong, D. Williamson, D.G. Cory, and R.L. Walsworth. Physical Review E 59, 1785 (1999).
• Pulsed-field-gradient measurements of time-dependent gas diffusion. R.W. Mair, D.G. Cory, S. Peled, C.H. Tseng, S. Patz, and R.L. Walsworth. Journal of Magnetic Resonance 135, 478 (1998).
• Low field MRI of laser polarized noble gas. C.H. Tseng, G.P. Wong, V.R. Pomeroy, R.W. Mair, D.P. Hinton, D. Hoffmann, R.E. Stoner, F.W. Hersman, D.G. Cory, and R.L. Walsworth. Physical Review Letters 81, 3785 (1998).
• NMR of laser polarized ¹²⁹Xe in blood foam. C.H. Tseng, S. Peled, L. Nascimben, E. Oteiza, R.L. Walsworth, and F.A. Jolesz. Journal of Magnetic Resonance 126, 79 (1997).
• Gradient echo imaging considerations for hyperpolarized ¹²⁹Xe MR. L. Zhao, R. Mulkern, C.H. Tseng, D. Williamson, S. Patz, R. Kraft, R.L. Walsworth, F.A. Jolesz, and M.S. Albert. Journal of Magnetic Resonance, Series B 113, 179 (1996).
• Determinants of tissue delivery for ¹²⁹Xe magnetic resonance in humans. S. Peled, F.A. Jolesz, C.H. Tseng, L. Nascimben, M.S. Albert, and R.L. Walsworth. Magnetic Resonance in Medicine 36, 340 (1996).
• Temporal dynamics of hyperpolarized ¹²⁹Xe resonances in living rats. K. Sakai, A.M. Bilek, E. Oteiza, R.L. Walsworth, D. Balamore, F.A. Jolesz, and M.S. Albert. Journal of Magnetic Resonance, Series B 111, 300 (1996).
• Hyperpolarized ¹²⁹Xe MR imaging of the oral cavity. M.S. Albert, C.H. Tseng, D. Williamson, E.R. Oteiza, R.L. Walsworth, B. Kraft, D. Kacher, B.L. Holman, and F.A. Jolesz. Journal of Magnetic Resonance, Series B 111, 204 (1996).

• Recent Publications

  • Dependence of nuclear spin singlet lifetimes on RF spin-locking power. S. J. DeVience, R. L. Walsworth, M. S. Rosen. Journal of Magnetic Resonance 218, 5 (2012).
  • Silicon Nanoparticles as Hyperpolarized Magnetic Resonance Imaging Agents. J.W. Aptekar, M.C. Cassidy, A.C. Johnson, R.A. Barton, M.Y. Lee, A.C. Ogier, C. Vo, M.N. Anahtar, Y. Ren, S.N. Bhatia, C. Ramanathan, D.G. Cory, A.L. Hill, R.W. Mair, M.S. Rosen, R.L. Walsworth and C.M. Marcus. ACS Nano. 3 12, 4003-4008 (2009).