SQUID-Controlled Noise Reduction Coils for Fetal MCG

描述（由申请人提供）： 本提案的目标是创建一种低成本、重量轻的有源降噪系统，以消除心磁图（MCG），特别是胎儿心磁图（fMCG）的电磁噪声干扰。该设备将沿沿着一个测量轴运行，这可能足以满足fMCG的要求。尽管MCG（和MEG）为临床医生提供了独特的、非侵入性的生物功能诊断措施，但该技术易受环境电磁噪声的影响，需要使用大规模且昂贵的磁屏蔽室（MSR），这对许多场所来说是不切实际的。我们建议用一个结合两个商业开发组件的系统来取代用于fMCG的MSR：主动消除和参考SQUiD。我们的系统将仅重数百磅，成本约为MSR的1110英镑。该系统将是一个亥姆霍兹线圈降噪设备，但将是新颖的，不是由室温（磁通门）磁力计驱动，而是由一组SQUID参考通道内置到MCG测量仪器本身。初步结果表明，噪声消除在100 Hz以下最有效，这将覆盖许多临床感兴趣的信号，并且在MSR性能最差的低频（.01 - 1 Hz）下尤其有效。 降噪系统将降低研究和临床MCG仪器的成本并提高性能，并将有助于将非侵入性MCG纳入更多研究人员，临床研究人员和临床专家的预算范围。对于小型、轻型MCG系统（包括在氮气温度下运行的系统）来说，这一优势尤其明显。与MEG和成人MCG相比，fMCG应用的选择是重要的，因为无创胎儿EKG是不可能的;单个MCG数据通道是非常宝贵的（定位不是问题）;感兴趣的信号相对于MEG诱发场（50-100 fT）较大（1-10 pT）。该计划将涉及修改现有的放大器和线圈组，已经开发的商业ETS-Lindgren。特里斯坦将建立一个基于SQUID的仪器，基于自己的商业系统，从以前的生物年龄应用测试的组件。该系统将在真实的噪声环境中进行测试，并在不同距离处使用已知的噪声源。

DESCRIPTION (provided by applicant): The goal of this proposal is to create a low cost, lightweight, active noise reducing system to quiet electromagnetic noise interference for magnetocardiography (MCG), especially fetal magnetocardiography (fMCG). The device will operate along one measurement axis, which may suffice for fMCG Although MCG (and MEG) provides clinicians with unique, noninvasive diagnostic measures of biological function, the technology is vulnerable to environmental electromagnetic noise, necessitating the use of massive and expensive magnetically shielded rooms (MSRs), which are impractical for many sites. We propose to replace the MSR for fMCG with a system combining two commercially developed components: active cancellation and reference SQUiDs. Our system will weigh just hundreds of pounds and will be approximately 1110 the cost of an MSR. The system will be a Helmholtz-coil noise reduction device, but will be novel in not being driven by room-temperature (fluxgate) magnetometers, but instead by a set of SQUID reference channels built into the MCG measurement instrument itself. Preliminary results suggest that the noise cancellation will be most effective below 100 Hz, which will cover many signals of clinical interest, and will be especially effective at low frequencies (.01 - 1 Hz) where MSR performance is poorest. The noise reduction system will lower costs and improve performance for research- and clinical MCG instruments, and will help bring noninvasive MCG into the budgetary range of more researchers, clinical researchers, and clinical specialists. This advantage will be especially strong for small scale, lightweight MCG systems, including those that operate with nitrogen temperature SQUiDs. The choice of fMCG application, in comparison with MEG and adult MCG is significant, since noninvasive fetal EKG is impossible; a single MCG channel of data is invaluable (localization is not at issue); and the signal of interest is large (1-10 pT) in relation to MEG evoked fields (50-100 fT). The plan will involve modifying an existing amplifier and coil set, already developed commercially by ETS-Lindgren. Tristan will build a SQUID-based instrument, based on its own commercial systems, from components tested on prior biomagetism applications. The system will be tested in a realistic noise setting, and with known noise sources at varying distances.