Applied Optics Group

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Bill Hersman checking polarizer status
Professor Bill Hersman check polarizer status with undergraduate intern Igor Tsentalovich

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MagniXene
MagniXene™ single-breath MR image of a 22 y.o. female healthy volunteer.

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xenon-tuned chest coil
Dr. Dregely’s work included the development of a xenon-tuned chest coil with 32 radiofrequency receive elements to detect the imaging signals from MagniXene™

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2011 ISMRM Young Investigator Award ceremony
Kai Ruppert (UVa), Isabel Dregely (UNH), and Bill Hersman (UNH and Xemed) at the 2011 ISMRM Young Investigator Award ceremony

Over the past twenty years, members of the UNH Physics Department have been investigating Spin Exchange Optical Pumping (SEOP) to identify new technologies for producing nuclear polarized gases. Originally these efforts were motivated by applications in fundamental physics. Because the lone neutron in 3He dominates the spin and magnetic properties of the composite nucleus, a dense gas of highly polarized 3He can serve as a surrogate neutron target for electron scattering experiments. Also, polarized3He preferentially absorbs neutrons of opposite spin direction allowing volumes of polarized 3He gas to serve as analyzers of neutron polarization in neutron scattering experiments.

More recently our efforts to improve SEOP technologies are also motivated by opportunities to apply hyperpolarized gas as a diagnostic tracer of inhaled lung gas with Magnetic Resonance Imaging. Typically an MRI scanner will study the tissues of the human body by aligning (polarizing) the protons in these tissues using its strong magnetic field. However SEOP can achieve hyperpolarizations nearly a million times greater. Since 1997 our group has been pursuing a new method for hyperpolarizing 129Xe formedical imaging. Our method flows axenon gas mixture at low pressure andhigh velocity through a long chamber against the direction of propagation of the laser beam, efficiently accumulating very high polarizations. This technology motivated the spinout of a small startup company Xemed LLC.

The UNH Center for Hyperpolarized Nuclei collaborates with Xemed and with clinical partners nationwide to demonstrate applications of hyperpolarized 129Xe. Recent UNH Physics graduate student Isabel Dregely performed PhD thesis work by collaborating with Xemed and outside academic institutions. In collaboration with the Martinos Center for Biomedical Imaging at the Massachusetts General Hospital we implemented a 32-elementchest coil for accelerated parallel imaging. In collaboration with the University of Virginia Center for In-Vivo Hyperpolarized Gas MR Imaging we implemented new scanner pulse-sequences to interrogate the saturation rate of xenon entering lung tissues. For her work, Isabel Dregely was honored with the W.S Moore Young Investigator Award by the International Society of Magnetic Resonance in Medicine.

Current projects include refinements of the technology for polarizing helium-3 and xenon-129 and clinical applications. Our technical projects include polarizer refinements to improve polarization and reduce losses, methods to move polarized gases both locally and over long distances without losing the polarization, development of new  powerful line-narrowed pump laser architectures, and development of an inhalation apparatus and RF coil to image premature infants. Clinical studies with collaborators include investigating methods to image premature infants (with University of Missouri) and guiding bronchial thermoplasty to modify airways of severe asthmatics (with Washington University in St. Louis).

Professor: Bill Hersman