Abstract: There is provided a magnetic shield which can shield external magnetic fields in the direction of an axis of a tubular magnetic shield and in the direction vertical to the axis. A magnetic shield has a cylindrical ferromagnetic substance 2-1 having openings on both ends and two superconducting loops housed in the respective insides of superconducting loop containers 1-1, 1-2. The superconducting loops are constructed of high critical temperature superconducting wire. The two superconducting loops have semicircle shapes and are arranged in x-direction so as to be symmetrical with respect to an axis of the cylindrical ferromagnetic substance 2-1. The superconducting loop containers 1-1, 1-2 are arranged in the insides near both open ends of the cylindrical ferromagnetic substance 2-1 with supports 20. The superconducting loops are arranged to be vertical to the axis of the cylindrical ferromagnetic substance 2-1. The superconducting loops are cooled by liquid nitrogen or a refrigerator.

Abstract: The distribution of the impedance characteristic of a test object is detected by applying an alternate magnetic field of a low frequency to the test object and measuring the induced current generated therefrom.

Abstract: A biomagnetic field measuring apparatus has a plurality of fluxmeters disposed externally of a living body and each including a superconducting quantum interference device (SQUID) for detecting a biomagnetic field generated from the living body, the plurality of fluxmeters being operative to detect a temporal change of a component of the biomagnetic field in a first direction which is vertical to the surface of the living body, an operation processor for performing computation for determining a temporal change of a value proportional to a root of square sum of differential value of the first-direction magnetic field component in second and third directions which cross the first direction and computation for integrating the temporal change of the value over a predetermined interval to determine an integral value, and a display for displaying the determined integral value. Distribution of magnetic fields generated from the heart is determined with a small number of fluxmeters.

Abstract: A biomagnetic measurement technique which can obtain a potential waveform corresponding to a ventricular muscle cell action potential in a non-invasive manner. The biomagnetic measurement apparatus including an operating circuit for magnetometer. The output data of the operating circuit for the magnetometer is collected and a current vector at time t is calculated. Further, an absolute value Ixy of the current vector, a potential waveform V (t) in time corresponding to depolarization of a heart from the absolute value of the current vector, and a potential waveform V (t) in a refractory period of the heart to a period corresponding to repolarization from the absolute value of the current vector are calculated.

Abstract: Disclosed herein is a biomagnetic measurement apparatus capable of visualizing cardiac electrical current distributions with information on the cardiac morphology of a subject. A magnetic field component in the z direction, vertical to the chest surface of a subject, is measured from two directions, front and back of the chest, and then to calculate the current distributions in the two directions and the distributions of the amplitudes of those current distributions. A three-dimensional standard heart model is created from average data on the cardiac morphology obtained from plural healthy subjects. An optimal position of the model is determined using the coordinates of the sinus node and the coordinates of the left ventricle. Then, a weight coefficient is obtained by front and back current distributions and front and back the distributions of the amplitudes of those current distributions on a set boundary of the model.

Abstract: The present invention discloses a magnetic detecting device comprising an apply coil 1 for generating an alternate magnetic field of variable frequency and a power source 2 for the apply coil; a magnetic sensor 5 for detecting a change in the magnetic field induced by a test object 9 placed at a distance from a surface of said apply coil and toward said test object, said magnetic sensor being provided with a cancel coil 6 for canceling a magnetic field generated at the position of the magnetic sensor by a direct magnetic field and/or said apply coil; a measurement circuit 7 for the magnetic sensor for measuring a detection signal of said magnetic sensor; a lock-in amplifier circuit 8 for detecting an output of said measurement circuit for the magnetic sensor into two signals having the same frequency as that of said apply coil and phases different from each other by 90 degrees; and an analysis means 10 for analyzing a phase change of the output of said magnetic sensor 5 using an output signal from said lock-i

Abstract: 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.

Abstract: A display method for a magnetic field measuring apparatus which includes detecting a magnetic field generated from a biotest sample by a plurality of magnetic sensors and displaying measurement data obtained on the basis of the detected magnetic field in any display mode, which further comprises displaying an operating information display screen, the operating information display screen having a processing function display section selecting an operation menu including a biotest sample list, data measurement or data analysis; a biotest information display section; and a data display area.

Abstract: A biomagnetic field map display apparatus for measuring a biomagnetic field generated by a biotest sample at positions arranged in rows and columns and displaying a magnetic field map obtained by processing the measured biomagnetic field. An analysis data display area waveform-displays the measured biomagnetic field at channels in a row or a column of channels which are arranged in rows and columns so as to respectively correspond to the positions. A particular channel is designated as a reference channel for an averaging process out of the plurality of channels or different channels therefrom at which different biosignals from those of the biomagnetic field are acquired from the biotest sample. Means for averaging-processing the measured biomagnetic field using the designated particular channel as the reference channel displays in the analysis data display area a map on the averaging-processed biomagnetic field.

Abstract: A magnetic field measurement apparatus which reduces an interference magnetic field entering into a pick-up coil is provided. The magnetic field measurement apparatus includes a superconducting quantum interference device (SQUID) magnetometer having a pick-up coil for picking up a magnetic field generated from an examination object, a SQUID control unit for controlling the SQUID magnetometer, a magnetometer for picking up the interference magnetic field, a magnetometer control unit for controlling the magnetometer, a modulation circuit, a current converter, a current amount adjusting device, a coil which is positioned outside the pick-up coil and through which the current thus adjusted by the current amount adjusting device flows, a demodulation circuit, a low-pass filter (LPF) for extracting a low frequency element of the output voltage from the demodulation circuit, and a subtraction circuit for subtracting the output of the LPF from the output of the SQUID control unit.

Abstract: A method for processing biomagnetic fields generated by biocurrents resulting from activities of human brain or myocardia and its mapping apparatus are provided, which features biomagnetic measurement and its analysis, magnetic field mapping and its imaging and their waveform generation by a simple operation. Biomagnetic fields emitted from the patient are measured at a plurality of measurement positions, and a contour map of magnetic field obtained as a result of processing of these measured biomagnetic fields is imaged in the magnetic contour map display apparatus, which display apparatus comprises: the process function display area indicating process function items including measurement; and the analysis data display area which displays the waveform together with a designated measurement time, the waveform being generated during measurement at least based on the measured biomagnetic fields and during the designated measurement period of time.

Abstract: Disclosed herein is a biomagnetic measurement apparatus capable of visualizing cardiac electrical current distributions with information on the cardiac morphology of a subject. A magnetic field component in the z direction, vertical to the chest surface of a subject, is measured from two directions, front and back of the chest, and then to calculate the current distributions in the two directions and the distributions of the amplitudes of those current distributions. A three-dimensional standard heart model is created from average data on the cardiac morphology obtained from plural healthy subjects. An optimal position of the model is determined using the coordinates of the sinus node and the coordinates of the left ventricle. Then, a weight coefficient is obtained by front and back current distributions and front and back the distributions of the amplitudes of those current distributions on a set boundary of the model.

Abstract: A living body inspection apparatus including an oscillation coil which passes an AC current, a detection coil which detects an AC magnetic field generated from the detection coil, an amplification circuit which amplifies a voltage generated by the magnetic field induced by the detection coil, a detecting unit for detecting the output signal of the amplification circuit, a low pass filter to which the output signal of the detecting unit is input, a unit for setting the oscillation coil and detection coil in first and second regions of the living body, a recording unit for recording the output of the low pass filter while the first region and the second region of the living body are moving and a displaying unit for displaying the data recorded in the recording unit or results of analysis of the recorded data.

Abstract: A magnetic field measurement system for canceling an external field is provided, in which plurality of sensing magnetometers (3) for measuring a magnetic field signal in a direction perpendicular to the center axis of a cylindrical magnetic shield (1) are arranged in two dimensions on a plane parallel to the center axis and a reference magnetometer (4) for measuring the external field parallel to the center axis as a reference signal is disposed on a plane perpendicular to the plane parallel to the center axis. The reference signal multiplied by a specified factor is subtracted from a difference between signals from the adjacent sensing magnetometers (3). The magnetic field measurement system allows measurement of an extremely weak magnetic field by efficiently canceling the external field.

Abstract: A magnetic field measurement apparatus includes a plurality of magnetometers each having SQUID's and three detection coils, one of which detects each of three orthogonal directional magnetic field components (Bx, By, Bz) of a magnetic field generated from a subject to be inspected, a display which displays time variation of waveforms of the magnitude (?(Bx2+By2+Bz2)) of magnetic field synthesized by square sum of each of the three orthogonal directional magnetic field components of the magnetic field generated from the subject to be inspected, a holder for holding a Dewar's vessel for arranging magnetometers therein, and a controller for controlling a positional relationship between the subject to be inspected and the Dewar's vessel.

Abstract: The present invention provides a magnetic field measurement apparatus which reduces an interference magnetic field entering into a pick-up coil. The magnetic field measurement apparatus includes, a SQUID magnetometer having a pick-up coil for picking up a magnetic field generated from an examination object, a SQUID control unit for controlling the SQUID magnetometer, a magnetometer for picking up the interference magnetic field, a magnetometer control unit for controlling the magnetometer, a modulation circuit, a current converter, a current amount adjusting means, a coil which is positioned outside the pick-up coil and through which the current thus adjusted by the current amount adjusting means flows, a demodulation circuit, a low-pass filter (LPF) for extracting a low frequency element of the output voltage from the demodulation circuit, and a subtraction circuit for subtracting the output of the LPF from the output of the SQUID control unit.

Abstract: A magnetic field measurement system for canceling an external field is provided, in which plurality of sensing magnetometers (3) for measuring a magnetic field signal in a direction perpendicular to the center axis of a cylindrical magnetic shield (1) are arranged in two dimensions on a plane parallel to the center axis and a reference magnetometer (4) for measuring the external field parallel to the center axis as a reference signal is disposed on a plane perpendicular to the plane parallel to the center axis. The reference signal multiplied by a specified factor is subtracted from a difference between signals from the adjacent sensing magnetometers (3). The magnetic field measurement system allows measurement of an extremely weak magnetic field by efficiently canceling the external field.

Abstract: An apparatus can detect a magnetic field with a high sensitivity using an ordinary-temperature pickup coil even when the pickup coil is arranged outside a cryostat. Specifically, the apparatus for measuring a magnetic field includes a pickup coil for detecting an external magnetic field, a SQUID electrically or magnetically connected to the pickup coil, a cryostat for holding the SQUID at low temperatures, and a driving device for driving the SQUID. The pickup coil is made of a normal-conducting material and is placed at an ordinary temperature outside the cryostat. By arranging outside the cryostat, the pickup coil can be brought close to a subject and can thereby detect a weak magnetic field in the subject with a high sensitivity.

Abstract: The present invention provides a biomagnetic measurement technique which can obtain a potential waveform corresponding to a ventricular muscle cell action potential in a non-invasive manner. The biomagnetic measurement apparatus including an operating circuit for magnetometer, and means collecting output data of the operating circuit for magnetometer, has means calculating a current vector at time t, means calculating absolute value Ixy of the current vector, means calculating potential waveform V (t) in time corresponding to depolarization of a heart from the absolute value of the current vector, and means calculating potential waveform V (t) in a refractory period of the heart to a period corresponding to repolarization from the absolute value of the current vector.

Abstract: A biomagnetic field measuring apparatus has a plurality of fluxmeters disposed externally of a living body and each including a superconducting quantum interference device (SQUID) for detecting a biomagnetic field generated from the living body, the plurality of fluxmeters being operative to detect a temporal change of a component of the biomagnetic field in a first direction which is vertical to the surface of the living body, an operation processor for performing computation for determining a temporal change of a value proportional to a root of square sum of differential value of the first-direction magnetic field component in second and third directions which cross the first direction and computation for integrating the temporal change of the value over a predetermined interval to determine an integral value, and a display for displaying the determined integral value. Distribution of magnetic fields generated from the heart is determined with a small number of fluxmeters.