Increase of Nuclear Magnetic Resonance Signal in Ultra-low-field by Hyperpolarization of ¹³¹Xe by Spin-exchange Optical Pumping

Abstract

Magnetic resonance imaging (MRI) has been used in clinical as major tomographic inspection with CT scans. Compared with CT, MRI has a number of advantages for example no radiation exposure. However, MRI has also disadvantages e.g. large size, high cost and never use to patients who have implant devices or metals because have to use strong field. Therefore, ultra-low-field MRI (ULF-MRI) has attracted attention because of usage of ultra-low fields such as earth field about 40∼50 μT. But there is a fatal weakness of ULF-MRI which SN ratio decreases. In this paper we show that spin-exchange optical pumping (SEOP) can increase ¹³¹Xe nuclear magnetic resonance (NMR) signals. We also show that SEOP is possible at very low power LASER with field in pulse sequence of NMR measurement.