Conformal pediatric whole-head MEG system with optically-pumped magnetometers

 描述（由申请人提供）：我们对从出生到学龄前的关键几年中正常和异常脑功能发育的理解存在重大差距。这些差距在很大程度上是由于有限的方法，非侵入性地检查在信息处理过程中大脑区域之间的动态时空相互作用的演变，其中小的头部尺寸排除了脑磁图（MEG），只留下空间分辨率相对较差的脑电图（EEG）。我们建议开发一个脑磁图系统，可以检测体感诱发磁场（SEF）在儿童触觉刺激单次试验产生的信号平均。我们将评估与脑电图（EEG）和最好的儿科MEG系统（babyMEG）相比，该系统更好地分离离散皮层源的能力。该系统基于非制冷微制造光泵磁力计（µOPM），而不是传统MEG系统中使用的超导量子干涉器件（SQUID）。新型传感器可以实现：1）MEG可以适合任何尺寸和形状的头部，2）每个µOPM探头和头皮之间的最小间隙（<4 mm）以增加信号强度，3）小尺寸允许非常接近的传感器间距（~15 mm）以提高空间分辨率，以及4）并行制造大型晶圆，这可以降低操作和系统成本。我们设想在未来的系统，这是更相似的EEG系统的成本，多功能性和易用性。我们有三个具体目标：目标1A：开发一个高灵敏度的单通道µOPM MEG系统，其磁强计具有<7 fT/vHz噪声水平和200 Hz带宽。目标1B：实现基线为2 cm、噪声电平<10 fT/vHz、共模抑制比（CMRR）为150的µOPM梯度计。目标2A：研制64通道梯度仪脑磁图系统。我们将改进用于大规模制造µOPM探针的方法，通过开发并行制造工艺而不是串行制造工艺，强调简化以降低成本、再现性和质量控制。目标2B：在美国国家标准与技术研究院（NIST）的标准2层MSR中，在体模和健康成年志愿者上组装和测试64通道µOPM MEG系统。目标3A：在波士顿儿童医院（BCH）的MEG机构评估健康儿童（0-36个月）的64通道系统，重点是在单次试验中检测SEF并确定定位误差。目标3B：评估系统的能力， 定位癫痫患者（1-3年）的发作间期发生器，并分离多个发生器。通过直接比较来自µOPM MEG和基于SQUID的375通道儿科MEG系统（“babyMEG”）的数据，我们希望不仅证明µ OPM用于MEG的可行性，而且还能获得更好的MEG图像，并具有实际优势。

 DESCRIPTION (provided by applicant): There are major gaps in our understanding of the development of normal and abnormal brain function in the critical years from birth to preschool. These gaps are due in large part to limited methods for non-invasively examining the evolution of dynamic spatiotemporal interactions between brain regions during information pro- cessing, where small head size rules out magnetoencephalography (MEG), leaving only electroencephalography (EEG) with relatively poor spatial resolution. We propose to develop a MEG system that could be able to detect somatosensory evoked magnetic field (SEF) in children produced by tactile stimulation on single trials without signal averaging. We will evaluate the ability to better separate discrete cortical sources with the proposed system as compared to electroencephalography (EEG) and the best pediatric MEG system available (babyMEG). The proposed system is based on uncooled microfabricated optically-pumped magnetometers (µOPM) instead of the Superconducting QUantum Interference Devices (SQUIDs) used in conventional MEG systems. The new type of sensors could enable: 1) a MEG that can fit the head of any size and shape, 2) minimal gap (< 4mm) between each µOPM probe and the scalp for increased signal strength, and 3) a small footprint allowing very close sensor spacing (~15 mm) for improved spatial resolution, and 4) manufacturing on large wafers in parallel, which can reduce operating and system cost. We envision a system in the future, which is much more similar to and EEG system with respect to cost, versatility, and ease of use. We have 3 specific aims: Aim 1A: Develop a highly sensitive 1-channel µOPM MEG system with a magnetometer having <7 fT/vHz noise level and 200 Hz bandwidth. Aim 1B: Implement a µOPM gradiometer with a baseline of 2 cm, a noise level of <10 fT/vHz, and a common-mode rejection ratio (CMRR) of 150. Aim 2A: Develop a 64-channel gradiometer MEG system. We will refine our method for large-scale fabrication of the µOPM probes, emphasizing simplification for cost reduction, reproducibility, and quality control by developing a parallel fabrication process instea of a serial one. Aim 2B: Assemble and test the 64-channel µOPM MEG system on a phantom and healthy adult volunteers in a standard 2-layer MSR at the National Institute of Standards and Technology (NIST). Aim 3A: Evaluate the 64-channel system in healthy children (0-36 months) at the MEG facility of Boston Children's Hospital (BCH) with a focus on detecting SEFs in single trials and determining localization errors. Aim 3B: Evaluate the ability of the system to localize interictal generators in epilepsy patients (1-3 years) and separate multiple generators. By directly comparing data from the µOPM MEG and a 375-channel pediatric MEG system ("babyMEG") based on SQUIDs from healthy children and epilepsy patients we expect to demonstrate not only the feasibility of µOPMs for MEG, but also better MEG images paired with practical advantages.