Progress in Superconductivity

The Korean Superconductivity Society (한국초전도학회)
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Measurement of fMCG Signals using an Axial Type First-Order SQUID Gradiometer System

권선형 1차 미분계를 이용한 태아심자도 신호 측정

  • Yu, K.K. (Korea Research Institute of Standards and Science) ;
  • Kim, K. (Korea Research Institute of Standards and Science) ;
  • Kang, C.S. (Korea Research Institute of Standards and Science) ;
  • Kim, J.M. (Korea Research Institute of Standards and Science) ;
  • Lee, Y.H. (Korea Research Institute of Standards and Science)
  • Published : 2009.04.30
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Abstract

We have fabricated a low-noise 61-channel axial-type first-order gradiometer system for measuring fetal magnetocardiography(MCG) signals. Superconducting quantum interference device(SQUID) sensor was based on double relaxation oscillation SQUID(DROS) for detecting biomagnetic signal, such as MCG, magnetoencphalogram(MEG) and fetal-MCG. The SQUID sensor detected axial component of fetal MCG signal. The pickup coil of SQUID sensor was wound with 120 ${\mu}m$ NbTi wire on bobbin(20 mm diameter) and was a first-order gradiometer to reject the environment noise. The sensors have low white noise of 3 $fT/Hz^{1/2}$ at 100 Hz on average. The fetal MCG was measured from $24{\sim}36$ weeks fetus in a magnetically shielded room(MSR) with shielding factor of 35 dB at 0.1 Hz and 80 dB at 100 Hz(comparatively mild shielding). The MCG signal contained maternal and fetal MCG. Fetal MCG could be distinguished relatively easily from maternal MCG by using independent component analysis(ICA) filter. In addition, we could observe T peak as well as QRS wave, respectively. It will be useful in detecting fetal cardiac diseases.

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References

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