Hitachi-High-Technologies Corporation

Hitachi, Ltd.

Waseda University

Masahiro Murakami

Akihiko Kandori

Keiji Tsukada

Tsuyoshi Miyashita

Daisuke Suzuki

Yusuke Seki

Hitoshi Sasabuchi

Mitsuru Onuma

Kuniomi Ogata

Atsushi Ishiyama

Atsushi Watanabe

Takuya Akashi

Yumie Ono

Yoshio Matsuoka

In magnetocardiography, an assisting technique for a doctor diagnosing a heart disease will be provided. In the magnetocardiography, magnetism to be generated from a subject's heart is measured by a magnetic sensor, and from this measured data, a position of center of gravity of excitement wave front in a cardiac muscle excitement propagation process and a transition vector (wave front vector) is calculated by an analyzing computer. With this wave front vector as a feature parameter, the Mahalanobis' distance is calculated from a data base obtained by diagnosing in the past, a possibility (probability) of the subject having a heart disease is presumed on the basis of the Bayes' theorem for displaying. Also, by superimposing on a heart picture, the wave front vector position is displayed, and a cluster classification position in the wave front vector is displayed. Also, by the similar retrieval, another subject extremely similar to the subject in the feature parameter will be retrieved from the data base for screen displaying.

Magnetocardiograph

A biomagnetic field measuring apparatus for performing (1) processes for removing a magnetic field waveform generated by a maternal heart from a waveform of a biomagnetic field measured, (2) processes for obtaining a template waveform of a magnetic field waveform generated by the fetal heart from a waveform, from which the magnetic field waveform generated by the maternal heart has been removed, (3) processes for obtaining a waveform of a cross correlation coefficient between the waveform, from which the magnetic field waveform generated by the mother's hears was removed, and the template waveform, and (4) a process for detecting peaks from a waveform of the cross correlation coefficient, and displaying times of appearance of the detected peaks on a display unit.

Biomagnetic field measuring apparatus

The object of the invention is to provide a biomagnetism measuring device using a high-performance cylindrical shielding apparatus provided with a flange-type plate having an opening formed on a circumferential face, an auxiliary cylinder in which one or plural cylindrical members are connected so that the central axis of the opening of the flange-type plate and each central axis of the cylindrical members are coincident, cylindrical shields having first, second and third angular ranges with the y-axis, a revolving door having a cutout in a portion parallel to the y-axis and acquired by integrating the cylindrical shields, shield bases for supporting the cylindrical shield to which the flange-type plate is connected in a circular-arc part at both ends, revolving parts for revolving the revolving door in a circumferential direction of the y-axis along a circumferential part of the cylindrical shield and opening or closing an opening in the circumferential direction, a cryostat arranged inside the opening of the auxiliary cylinder and the opening and a SQUID fluxmeter arranged on a measurement face parallel to an XY plane inside the cryostat held at low temperature and characterized in that the circumferential part of the cylindrical shield is inserted between the circumferential parts of the cylindrical shields when the revolving door is closed, cylindrical internal space is formed and an environmental magnetic field that invades the internal space is screened.

Magnetic shielding apparatus and biomagnetism measuring device

A biomagnetic measurement apparatus having functions to detect the release of a magnetic field lock in a SQUID fluxmeter operation circuit due to the influence of a much greater noise level than that of a biomagnetic signal, to notify an operator of the release of the magnetic field lock, and to automatically or manually revert to a state for allowing magnetic measurement. The release of the magnetic field lock occurs when an integrator of the fluxmeter operation circuit is saturated. Thus, a high pass filter is provided at a subsequent stage of the integrator, and a function is provided to judge that the integrator is in a saturated state when the noise level of the output after passing through the high pass filter is lower than a pre-set threshold. The biomagnetic measurement apparatus can detect a saturated state of the integrator, which is a cause for the release of the magnetic field lock of the SQUID fluxmeter operation circuit, and thereby when the loading of measured data is conducted in an appropriate operation range of a magnetic sensor, or even when a part of the loaded measured data is data outside an operation range of the magnetic sensor, it is possible to deal with the data so as to properly analyze it.

Biomagnetic measurement apparatus

A biomagnetic field measuring apparatus including: a plurality of magnetometers each employing a superconducting quantum interference device for measuring the magnetic field generated from an organism; a unit for calculating a pseudo-current from a normal component of the magnetic field; a unit for calculating the pseudo-current from the magnetic field obtained from the plurality of magnetometers to integrate the pseudo-current in a fixed direction on the circumference at a fixed distance from each of the associated ones of the sensors; a unit for calculating a maximum value or a minimum value of the integral value obtained by the unit for performing the integral; and a unit for calculating a difference value between the absolute value of the maximum value and the absolute value of the minimum value.

Biomagnetic field measuring apparatus using squid magnetometers for evaluating a rotational property of a current in a subject

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Hitachinaka, Japan

Masahiro Murakami