Medical Imaging
| Over the past twenty years, membersof the UNH Physics Department havebeen investigating Spin ExchangeOptical Pumping (SEOP) to identifynew technologies for producing nuclearpolarized gases. Originally these effortswere motivated by applications infundamental physics. Because thelone neutron in 3He dominates thespin and magnetic properties of thecomposite nucleus, a dense gas ofhighly polarized 3He can serve as asurrogate neutron target for electronscattering experiments. Also, polarized3He preferentially absorbs neutronsof opposite spin direction allowingvolumes of polarized 3He gas to serveas analyzers of neutron polarization inneutron scattering experiments. More recently our efforts toimprove SEOP technologies are alsomotivated by opportunities to applyhyperpolarized gas as a diagnostictracer of inhaled lung gas with MagneticResonance Imaging. Typically an MRIscanner will study the tissues of thehuman body by aligning (polarizing)the protons in these tissues using itsstrong magnetic field. However SEOPcan achieve hyperpolarizations nearlya million times greater. Since 1997our group has been pursuing a newmethod for hyperpolarizing 129Xe formedical imaging. Our method flows axenon gas mixture at low pressure andhigh velocity through a long chamberagainst the direction of propagation ofthe laser beam, efficiently accumulatingvery high polarizations. This technologymotivated the spinout of a smallstartup company Xemed LLC. The UNH Center for HyperpolarizedNuclei collaborates with Xemed and with clinical partners nationwideto demonstrate applications ofhyperpolarized 129Xe. Recent UNHPhysics graduate student IsabelDregely performed PhD thesis work bycollaborating with Xemed and outsideacademic institutions. In collaborationwith the Martinos Center for BiomedicalImaging at the Massachusetts GeneralHospital we implemented a 32-elementchest coil for accelerated parallelimaging. In collaboration with theUniversity of Virginia Center for In-Vivo Hyperpolarized Gas MR Imagingwe implemented new scanner pulse-sequences to interrogate the saturationrate of xenon entering lung tissues. Forher work, Isabel Dregely was honoredwith the W.S Moore Young InvestigatorAward by the International Society ofMagnetic Resonance in Medicine. Current projects include technologyrefinements and clinical applications.Our technical projects include polarizerrefinements to improve polarizationand reduce losses, coil innovationsto allow concurrent proton-xenondual nucleus imaging, and scannerpulse sequences that determine localoxygen concentrations in lungs. Clinicalstudies will investigate using diagnosticimaging to determine benefits of newdrugs, devices, and interventionalprocedures. 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, polarized 3He preferentially absorbs neutrons of opposite spin direction allowing volumes of polarized 3He gas to serveas 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 hyper polarizations nearly a million times greater. Since 1997 our group has been pursuing a new method for hyperpolarizing 129Xe for medical imaging. Our method flows a xenon gas mixture at low pressure and high velocity through a long chamber against the direction of propagation of the laser beam, efficiently accumulatingvery 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 saturationrate 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 technology refinements and clinical applications. Our technical projects include polarizer refinements to improve polarization and reduce losses, coil innovations to allow concurrent proton-xenondual nucleus imaging, and scanner pulse sequences that determine local oxygen concentrations in lungs. Clinical studies will investigate using diagnostic imaging to determine benefits of new drugs, devices, and interventional procedures. |
Professor Bill Hersman check polarizer status with undergraduate intern Igor Tsentalovich
MagniXene™ single-breath MR image of a 22 y.o. female healthy volunteer.
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™
Kai Ruppert (UVa), Isabel Dregely (UNH), and Bill Hersman (UNH and Xemed) at the 2011 ISMRM Young Investigator Award ceremony