Fujitsu Corporation

Yale University

Takao Goto

Takehiko Hayashi

Yutaka Igarashi

Yoshiyasu Nakashima

Takaki Shimura

Hajime Hayashi

Kenji Kawabe

Shinichi Amemiya

Norio Fujimaki

Kohtaro Gotoh

Roman B Kuc

James J Szinger

A method and apparatus for performing biomagnetic imaging to determine the location and intensity of current sources within a subject includes a sensor unit for sensing the magnetic field within the subject and for providing sensing signals. A signal processor defines a grid having multiple grid points and performs inverse estimation to determine the distribution of current sources on the defined grid based on the sensing signals. The signal processor then modifies the grid to improve the resolution of the current sources distributed on the grid. A control unit controls the operation of the signal processor and processes image data to provide magnified and non-magnified displays on a display unit. The biomagnetic imaging method and apparatus can be combined with a system for providing magnetic resonance imaging data so as to produce a superimposed display including an MRI image and a biomagnetic image.

Biomedical magnetism imaging apparatus and method

In a method/apparatus of the present invention, a plurality or pickup coils are employed at a plurality of detection points so as to measure magnetic field intensities induced from electric current generated on living organ: the detection points are spatially interpolated/extrapolated; equations to determine relations of a hypothetically located current to the magnetic field intensities at the detection points and the interpolated detection points are established; the magnetic field intensities are measured with the pickup coils; magnetic field intensities are estimated at the interpolated/extrapolated detection points from the magnetic field intensities measured by the pickup coils; and the hypothetically located electric current is calculated by applying said magnetic field intensities at the detection points and said interpolated/extrapolated detection points to said equation. Thus, the electric current value is estimated. The calculation is preferably carried out by a SVD method, where the hypothetically located current is placed at plural current source positions. Matrix constants in the SVD calculation is determined in advance to allow a quick calculation. The interpolated/extrapolated point may be determined according to a linear method or a spline method, or depending on the current location, or on the spatial differentiation of the magnetic field intensity, or may be changed with time.

Biologic magnetometer for determining an electric current distribution

A pick-up coil assembly for a multi-channel SQUID magnetometer. The assembly includes a base plate, a plurality of support bars fixedly mounted on the base plate so as to form a matrix, and a plurality of pick-up coil units fixedly mounted on the support bars, each pick-up coil unit having a first and second pick-up coil block. Each of the pick-up coil blocks has a support body, a pair of pick-up coils, connection pads and connection lines. The pair of pick-up coils, the connection pads and the connection lines are formed by a lithography technique on the support body.

Pick-up coil assemblies and system for use in a multi-channel squid

A plurality of SQUID flux sensors are supplied with their respective bias currents at the same time from a bias source. A superconducting multiplexer multiplexes output signals of the SQUID flux sensors during an interval of time when the bias currents are supplied to the SQUID flux sensors. A multiplexer, placed in a room-temperature environment, distributes each of the multiplexed output signals of the SQUID flux sensors to a respective one of the output terminals which correspond to the SQUID flux sensors. Each signal which has been output to an individual output terminal is counted by a counter, so that an external magnetic flux to a corresponding SQUID flux sensor is measured.

Multichannel SQUID flux meter having multiplexed SQUID flux sensors

A digital superconducting quantum interference device type fluxmeter includes a flux sensor unit which detects external magnetic flux to be measured using a SQUID ring, and outputs pulse signals of corresponding directions and numbers, and a counter unit which counts the number of pulse signals output by the flux sensor unit inclusive of the directions thereof, in order to measure the external magnetic flux based on the counted result of the counter unit. The fluxmeter further includes an offset detection unit which detects the offset quantity of the counter unit generated by the magnetic flux trapped by the SQUID ring, and a feedback unit that feeds back to the flux sensor unit a signal that is obtained based on the detected offset quantity and the counted result of the counter unit.

Digital magnetic flux measuring apparatus using superconducting quantum

In a multi-channel SQUID fluxmeter for detecting magnetic flux signals by use of an array of SQUID flux sensors each comprising a digital SQUID for providing a pulse output, multiplexers and the like are appropriately used to allow pulse signals output from the SQUID flux sensors to be switched on a time series basis in order to obtain a magnetic flux signal for each channel. Thus, only one processing circuit need to be provided for a large number of SQUID flux sensors, thus reducing the scale of the fluxmeter and making the device small.

Multi-channel SQUID fluxmeter with time division feedback

A digital SQUID control system for measuring a weak magnetic flux irradiated from an object includes: a SQUID having Josephson junctions and a superconductively coil; a pick-up coil detecting the weak magnetic flux from the object and flowing a measuring current in the pick-up coil, and an input coil magnetically coupled to the superconductivity coil through the measuring current; a feedback coil magnetically coupled to the superconductivity coil through a feedback current; a feedback circuit for counting positive and negative pulses input from the SQUID, for converting count values to an analog voltage, and for converting the analog voltage to the feedback current; an alternating has current generating circuit connected to the SQUID through an injection terminal, for supplying the alternating bias current to the SQUID; and a pulse rate measuring circuit for calculating a sum of the positive and negative pulses, for converting the sum to an analog voltage, and for outputting the analog voltage to the alternating current generating circuit. Further, the alternating current generating circuit controls an amplitude of the alternating bias current in such a way that the sum of the positive and negative pulses per unit of time becomes constant, and the feedback circuit controls the feedback current under the controls of the alternating bias current amplitude in such a way that a difference between the positive pulses and the negative pulses becomes zero by flowing the feedback current through the magnetically coupled superconductivity coil.

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Kawasaki, Japan

Takao Goto