Non-cryogenic Fieldable Interleaved Magnetoencephalography and Magnetic Resonance Imaging based on Multichannel Atomic Magnetometers

该提案旨在开发第一个非低温可现场多通道系统，以实现交叉 测量磁共振成像（MRI）在超低场（ULF）制度（<< 1 T）和磁- 脑电描记术（MEG）是对人类大脑的一种检查。这两种模式的结合是唯一能够连接 生物磁脑活动（MEG）的来源与特定的解剖脑结构（ULF MRI）， 出色的时间和空间分辨率。此外，该组合基本上消除了配准误差 基于常见的MEG-MRI坐标系。这种先进的生物医学技术将提高 了解人类大脑功能，帮助诊断和治疗多种大脑疾病，如 癫痫病灶，改善神经外科手术计划。以前，MEG-MRI组合仅实现 使用多个低温超导量子干涉器件（SQUID）传感器。然而，需求 用于低温冷却和屏蔽室是主要的缺点。我们将建造一个更实用的装置， SQUID与一种新型的原子磁力计（AM）。基于激光和碱金属蒸气电池， 是目前最灵敏的无冷冻剂磁传感器。具体目标是：（1）开发一个原创 紧凑型16通道AM模块，用于MEG。它提供了大量的传感通道的基础上，一个大的 蒸气室和两个宽的几乎平行的激光束。这种新方法导致成本大幅降低 与基于SQUID的MEG系统相比。(2)制作一个可穿戴的全头MEG头盔。我们将 生产15-20个紧凑型AM MEG模块，用于安装在头盔上，以实现全头部覆盖， 渠道由于激光器与光纤的耦合，模块位置可针对不同的头几何形状进行调整 以使传感器更接近头部。这将导致改进的定位和灵敏度。我们将获得 脑磁图头盔的功能图(3)构建一种基于单通道的新型多通道超低频MRI设备， 模块多通道AM耦合到多个通量变换器（FT）。对于MRI，将修改AM设计， 允许正交激光束，并将施加偏置磁场以将AM调谐到目标MRI频率 约200 kHz。每个FT将由两个连接的线圈组成，一个位于人体头部附近，另一个位于人体头部附近。 靠近AM蒸汽室，将MRI信号传输到AM。FT线圈可以灵活地布置在 以增强MRI信号。我们将展示人类头部的ULF MRI测量结果， 优化的FT阵列。(4)联合收割机将全头MEG头盔和ULF MRI设备结合在一台仪器中。 将通过将MRI FT线圈连接到MEG头盔来实现组合。该装置将安装在 在屏蔽室中验证可行性，然后在人体大小圆柱形高导磁合金磁屏蔽中形成 从而实现移动的应用。我们将对大脑活动和结构进行交错成像， 时间和空间分辨率我们还将开发用于数据采集/分析的MEG和MRI算法， 高精度生物磁源定位。

This proposal aims to develop a first non-cryogenic fieldable multichannel system to enable interleaved measurements of magnetic resonance imaging (MRI) in the ultra-low field (ULF) regime (<< 1 T) and magneto- encephalography (MEG) of the human brain. The combination of the two modalities is uniquely capable of linking the sources of biomagnetic brain activity (MEG) to the specific anatomical brain structure (ULF MRI) with both excellent temporal and spatial resolution. In addition, the combination essentially eliminates co-registration errors based on the common MEG-MRI coordinate system. This advanced biomedical technology will enhance understanding of human brain function, aid in diagnosis and treatment of multiple brain disorders such as the epileptic focus, and improve neurosurgical planning. Previously, the MEG-MRI combination was realized only using multiple cryogenic superconducting quantum interference device (SQUID) sensors. However, the demand for cryo-cooling and a shielded room is a major drawback. We will build a more practical device by replacing SQUIDs with a novel type of atomic magnetometers (AMs). Based on lasers and alkali-metal vapor cells, AMs are currently the most sensitive cryogen-free magnetic sensors. Specific aims are to: (1) Develop an original compact 16-channel AM module for MEG. It delivers a large number of sensing channels based on a single large vapor cell and two broad nearly parallel laser beams. This new approach leads to significant cost reduction compared to commercial SQUID-based MEG systems. (2) Construct a wearable full-head MEG helmet. We will produce 15–20 compact AM MEG modules for mounting on a helmet for full-head coverage with up to 320 channels. Due to the laser-to-fiber coupling, the module positions will be adjustable for different head geometries for closer proximity of sensors to the head. This will result in improved localization and sensitivity. We will obtain functional brain maps with the MEG helmet. (3) Construct a new multichannel ULF MRI device based on a single- module multichannel AM coupled to multiple flux transformers (FTs). For MRI, the AM design will be modified to allow orthogonal laser beams, and a bias magnetic field will be applied to tune the AM to target MRI frequencies of ~200 kHz. Each FT will be composed of two connected coils, one located near the human head and the other near the AM vapor cell, to transfer MRI signals to the AM. The FT coils can be flexibly arranged around the human head to enhance an MRI signal. We will demonstrate ULF MRI measurements of the human head with an optimized FT array. (4) Combine the full-head MEG helmet and the ULF MRI device in a single instrument. The combination will be achieved by attaching the MRI FT coils to the MEG helmet. The device will be installed in a shielded room for a proof of feasibility and then in a human-sized cylindrical mu-metal magnetic shield for enabling mobile applications. We will perform interleaved imaging of brain activity and structure with high temporal and spatial resolution. We will also develop MEG and MRI algorithms for data acquisition/analysis and high accuracy biomagnetic source localization.