A feasibility study on novel MEG and NMFD-fMRI with optically pumped atomic magnetometers

光泵原子磁强计(OPAM)具有不需要低温冷却的固有优势。因此，目前预计OPAM将超过SQUID。在这项研究中，我们致力于利用OPAM开发新型的脑磁图和功能磁共振成像。首先，我们试图提高OPAM的灵敏度，使其能够达到测量生物磁场的灵敏度。随后，我们演示了不仅要测量心磁图(MCGs)，还要测量脑磁图(MEGS)。同时，我们还开展了具有自旋锁定序列的磁共振成像的理论和实验研究，该序列有可能像功能磁共振成像一样检测神经磁场依赖(NMFD)的MR信号强度的变化。在这项研究中，我们可以观察到发生在自旋锁定脉冲和振荡磁场之间的二次磁共振。此外，我们计算出大约200pT的磁场可以被探测到。

Optically pumped atomic magnetometers (OPAMs) have the intrinsic advantage of not requiring cryogenic cooling. Therefore, OPAMs are currently expected to overtake SQUIDs. In this study, we tackle to develop novel MEG and fMRI using the OPAM. First, we tried to improve the sensitivities of the OPAM and could make it possible to reach its sensitivity capable for measure measuring biomagnetic fields. Subsequently, we demonstrated to measure not only magnetocardiograms (MCGs) but also magnetoencephalograms (MEGs). Meanwhile, we also carried out theoretical and experimental studies on a MRI with spin-lock sequence, which has potential to detect neural magnetic field dependent (NMFD) changes in MR signal intensities as fMRI. In this study, we could observe the secondary magnetic resonance occurring between the spin-lock pulses and oscillating magnetic fields with a loop coil phantom. In addition, we figured out that magnetic fields of approximately 200 pT could be detected.