A promising approach to portable MRI is operation at ultra-low magnetic field where cost-effective electromagnets become practical. MRI in the ultra-low field (ULF) regime —when the magnetic field used for signal detection is below 10 mT—is inherently challenging mainly due to intrinsically low Boltzmann polarization. We will discuss signal acquisition approaches and hardware methods to...
Creating and maintaining hyperpolarized states is difficult. Unsurprisingly, many of the same limitations are also present when considering biological and medical applications. T1, T2, diffusion or transport to the catalytic site of interest and relaxation processes while bound can all affect our ability to extract useful information from the hyperpolarized sample in vivo. Even when these...
INTRODUCTION: The vast majority of emerging hyperpolarized MRI contrast agents employ heteronuclei (e.g. 13C or 129Xe) for transient storage of hyperpolarization and detection due to much longer lifetimes of the HP state and the lack of background signal. However, clinical MRI scanners are often poorly suited for excitation and detection of heteronuclei as they typically lack the corresponding...
Nuclear spin hyperpolarization uncouples the magnitude of spin magnetization from that of an externally applied magnetic field, making NMR and magneto-optical measurements possible over a wide range of field strengths. In this presentation, we use dissolution dynamic nuclear polarization (D-DNP) and para-hydrogen induced polarization (PHIP) for measurements of NMR and nuclear spin optical...
Nuclear spin hyperpolarization has long been exploited to enable a host of applications, from fundamental physics experiments to enhanced NMR / MRI. In order to take such efforts in new directions, our lab’s collaborative work is investigating the use of two hyperpolarization methods – Spin-Exchange Optical Pumping (SEOP) and SABRE (Signal Amplification By Reversible Exchange, a...
The PREFER (Polarization REsearch for Fusion Experiments and Reactors) collaboration was born to address the challenge of achieving nuclear fusion with polarized fuel, for improved fusion-reactor efficiency, by bringing together techniques and know-how from different fields. Efforts are focused on a variety of tasks and objectives, which are under the responsibility of different institutes....
Over the years, several relaxation mechanisms have been identified, including dipolar coupling, chemical shift anisotropy, paramagnetic relaxation, spin rotation and spin-internal motion, and the scalar relaxation of the second kind. While in principle, many of the mechanisms are well understood, estimating their size can be difficult. Furthermore, multiple experimental examples have been...
The hyperpolarization technique Signal Amplification By Reversible Exchange (SABRE) distills spin polarization from parahydrogen during reversible chemical interactions of the target with a catalyst. Typically, the largest spin polarization can be generated at ultralow magnetic fields (B~10 μT). At these fields, roughly 5% spin polarization may be generated on nuclear targets like $^{13}C$ and...
Signal Amplification By Reversible Exchange (SABRE) is a hyperpolarization method that generates large, non-equilibrium spin polarizations by transferring spin order from parahydrogen ($|S_H ⟩$) to magnetized states on a target nucleus ($|α_L ⟩$). An iridium-based catalyst simultaneously and reversibly binds parahydrogen and a target ligand with spin-1/2 nuclear target(s) L. Under the right...
Level anticrossings (LACs) occur in diverse quantum systems and underpin a plethora of fascinating phenomena. Of particular interest here is the role of LACs in inducing nuclear spin hyperpolarization for sensitivity-enhanced nuclear magnetic resonance (NMR) spectroscopy and imaging. Theoretical and experimental manifestations of LACs in nuclear spin systems incorporating protons from...
Solid-state systems featuring optically polarizable electrons present intriguing possibilities due to the potential for local injection of spin polarization into neighboring nuclear spins. This process results in the enhancement of their magnetic resonance signatures by several orders of magnitude. In this talk, I will discuss the fascinating opportunities arising from these "hyperpolarized"...
