Production of laser-polarized 3He gas via metastability exchange optical pumping for magnetic resonance imaging

The state-of-the-art in the production of hyperpolarized 3He gas for magnetic resonance imaging (MRI) of the human lungs is reviewed. The paper is focused on the metastability exchange optical pumping (MEOP) method, which is preferable in medical applications, because the polarized 3He gas is free of any contaminants. Two strategies, namely, “centralized” and “onsite” production, are compared from the point of view of efficiency, level of achievable polarization, and the cost. A novel design of the polarizer that is based on MEOP operating in nonstandard conditions is also presented. It is the most promising solution for the implementation of the technique in medical clinics, as it uses the magnetic field of the MRI scanner and operates at elevated 3He gas pressure.