• B.S., 1989, University of Michigan
• Ph.D., 1995, Princeton University

Research Interests:

Professor Saam joined the faculty in October, 1999. He is currently interested in the physics and some of the many applications of laser-polarized noble gases. Certain gas isotopes (notably ³He and ¹²⁹Xe) can have their nuclear spins aligned (polarized) to 50% or more by undergoing collisional spin exchange with an optically pumped and polarized alkali-metal vapor. The polarizations of these so-called hyperpolarized gases are typically 4-5 orders of magnitude above thermal equilibrium, allowing all kinds of magnetic resonance experiments with them that are not otherwise possible because of the low density and corresponding weak signal intensity. Hyperpolarized gases are studied and used all over physics, including the study of fundamental symmetries, as polarized targets, and as neutron-spin filters.

Professor Saam’s most recent focus has been the application of hyperpolarized ³He to magnetic resonance imaging (MRI) of the lung in small animals and humans. Liter quantities of 50% polarized ³He gas can now be produced, inhaled by an animal or human volunteer, and thus used to provide an image of static or dynamic ventilation. Visualization of ventilation with such a high degree of spatial and temporal resolution has never before been possible, and the technique has tremendous potential for addressing important questions concerning the physiology of healthy and diseased lung. Professor Saam is currently initiating a collaboration with imaging and pulmonary scientists at Pacific Northwest National Laboratory. ³He MRI will be used to validate computational models of air flow in the lung.

In addition to the medical application, Professor Saam is also interested in the atomic physics of spin-exchange optical pumping and the study of condensed phases of hyperpolarized ¹²⁹Xe. This work includes NMR studies of the interaction of ³He with various surfaces and the possibility of transferring the large polarizations in ¹²⁹Xe to nuclei of interest in other substances, (e.g., biological molecules).

Selected Recent Publications

• "Wall Relaxation of ³He in Spin Exchange Cells" (with R.E. Jacob, S.W. Morgan and J.C. Leawoods), Phys. Rev. Lett. 87, 143004 (2001).
• "Hyperpolarized ³He Gas MR Imaging" (with J.C. Leawoods, D.A.Yablonskiy, et al.), Concpets Magn. Reson. 13, 277-293 (2001).
• "Polarization Transfer Using Hyperpolarized Supercritical Xenon," Chem. Phys. Lett. 327, 359-364 (2000).
• "NMR Imaging of Diffusion of ³He Gas in Healthy and Diseased Lungs" (with D.A. Yablonskiy, et al), Magn. Reson. Med. 44, 174-179 (2000).
• "Rapid Imaging of Hyperpolarized Gas Using EPI" (with D.A. Yablonskiy, et al.), Magn. Reson. Med. 42, 507-514 (1999).
• "Low Frequency NMR Polarimeter for Hyperpolarized Gases" (with M.S. Conradi), J. Magn. Reson. 134, 67-71 (1998).
• "Edge Enhancement Observed with Hyperpolarized ³He" (with N. Drukker and W. Happer), Chem. Phys. Lett. 264, 481-487 (1996).
• "Magnetic Resonance Imaging with Laser-Polarized Noble Gases," Nature Med. 2, 358-359 (1996).
• "Nuclear Relaxation of ³He in the Presence of O₂" (with W. Happer and H. Middleton), Phys. Rev. A 52, 862-865 (1995).
• "Biological Magnetic Resonance Imaging using Laser-polarized ¹²⁹Xe" (with M.S. Albert, G.D. Cates, et al.), Nature 370, 199-201 (1994).