In recent years, a magnetocardiography (MCG) with superconducting quantum interference device with noise level of 50 fT/√ Hz is used for arrhythmia diagnosis. The MCG is usually installed in a multilayered magnetically shielded room (MSR). In the MCG close to some magnetic noise sources like direct current (dc)‐electrified railway, the MCG can stably measure the magnetic field by increasing the number of layers of MSR. However, increasing the number of layers in the MSR increases the cost and weight. We developed the method to correct the environmental magnetic field (EMF) in the MCG that considers the reduction response of each EMF reduction technology of the MCG including the MSR by referring to the signal measured by the reference magnetic sensor outside the MSR. The effect of the correction was evaluated for each channel of the MCG by using the EMF signal from the dc‐electrified railway as the magnetic noise source. The average value of the correction effect was 18.1 dB, the standard deviation (SD) was 4.1 dB, and the 2SD range was from 9.8 to 26.4 dB. From these results, it is suggested that the developed method has the possibility to improve the EMF in the MCG by more than 9 dB.

中文翻译：

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心电图参考磁传感器对环境磁场噪声校正方法的研制

近年来，具有50 fT /√Hz噪声水平的带有超导量子干涉装置的心磁图（MCG）用于心律失常的诊断。MCG通常安装在多层磁屏蔽室（MSR）中。在靠近某些电磁噪声源（如直流（dc）电气化铁路）的MCG中，MCG可以通过增加MSR的层数来稳定地测量磁场。但是，增加MSR中的层数会增加成本和重量。我们开发了一种校正MCG中环境磁场（EMF）的方法，该方法考虑了MSR外部的参考磁传感器测得的信号，从而考虑了包括MSR在内的MCG的每种EMF降低技术的降低响应。通过使用来自直流电气化铁路的EMF信号作为磁噪声源，评估了MCG各个通道的校正效果。校正效果的平均值为18.1 dB，标准偏差（SD）为4.1 dB，2SD范围为9.8至26.4 dB。从这些结果可以看出，所开发的方法有可能将MCG中的EMF提高9 dB以上。