Hamamatsu-photonics K.k.

Kyoto University

Canon Kabushiki Kaisha

Tetsuo Kobayashi

Motohiro Suyama

Takahiro Moriya

Akinori Saito

Takenori Oida

Natsuhiko Mizutani

Sunao Ichihara

Shuji Taue

Hideyuki Sugioka

Yosuke Ito

Akira Terao

Norihisa Kato

Kiyoshi Ishikawa

A brain measurement apparatus includes: a static magnetic field forming unit for forming a static magnetic field in a measurement area; a gradient magnetic field coil for forming a gradient magnetic field in the measurement area; a transmission coil for transmitting a transmission pulse toward a subject in the measurement area; a detection coil for detecting a nuclear magnetic resonance signal generated in the subject by transmission of the transmission pulse; and a generator for generating an MR image based on the nuclear magnetic resonance signal detected by the detection coil.

Brain measurement apparatus

A brain measurement apparatus configured to generate an MR image and a brain's magnetic field distribution of a subject includes: an MRI module having a transmission coil configured to transmit a transmission pulse toward the subject and a detection coil configured to detect a nuclear magnetic resonance signal generated in the subject by the transmission pulse; an optically pumped magnetometer configured to detect a brain's magnetic field of the subject; a generator configured to generate the MR image based on the nuclear magnetic resonance signal detected by the detection coil and generating the brain's magnetic field distribution based on the brain's magnetic field detected by the optically pumped magnetometer; a marker displayed on the MR image generated by the generator; and a helmet-type frame to which the detection coil, the optically pumped magnetometer, and the marker are attached and which is attached to a head of the subject.

Brain measurement apparatus and brain measurement method

A brain measurement apparatus includes: a magnetoencephalograph including optically pumped magnetometers, magnetic sensors for measuring geomagnetic field at positions of the optically pumped magnetometers, magnetic sensors for measuring a fluctuating magnetic field at the positions of the optically pumped magnetometers, nulling coils for cancelling the geomagnetic field, and an active shield coil for cancelling the fluctuating magnetic field; an MRI apparatus including nulling coils for applying a static magnetic field and a gradient magnetic field, a transmission coil, and a receive coil; and a control device that, when measuring a brain's magnetic field, controls currents supplied to the nulling coils and the active shield coil based on measured values of the magnetic sensors and, when measuring an MR image, controls the static magnetic field and the gradient magnetic field by controlling currents supplied to the nulling coils and generates an MR image from an output of the receive coil.

A brain measurement apparatus includes: a magnetoencephalograph including optically pumped magnetometers, magnetic sensors for measuring a static magnetic field at positions of the optically pumped magnetometers, and a nulling coil for canceling the static magnetic field; an MRI apparatus including a permanent magnet, a gradient magnetic field coil, a transmission coil, and a receive coil for detecting a nuclear magnetic resonance signal; and a control device that, when measuring the brain's magnetic field, controls a current to be supplied to the nulling coil based on measured values of the magnetic sensors and operates so as to cancel a static magnetic field at the position of each of the optically pumped magnetometers and, when measuring an MR image, controls the gradient magnetic field by controlling a current to be supplied to the gradient magnetic field coil and generates an MR image based on an output of the receive coil.

Provided is a brain measurement system including: a geomagnetic correction coil; a geomagnetic gradient correction coil; a transmission coil; a receiving coil; a plurality of resonance adjustment circuits; a plurality of OPM modules provided corresponding to each of the plurality of resonance adjustment circuits for detecting a signal having a resonance frequency output from the resonance adjustment circuit; and a control device for generating an MR image based on the signal detected by the OPM module, wherein, when a direction parallel to a central axis of a head portion of a subject is defined as a Z-axis direction, the resonance frequency related to each of the plurality of resonance adjustment circuits is set according to a magnetic field gradient in the Z-axis direction generated by control of a position of the corresponding receiving coil in the Z-axis direction and a tilted magnetic field.

Brain measurement system

An optically pumped magnetometer includes cells configured to form a first cell region and a second cell region on a measurement target, a pump laser, a probe laser, a first optical system configured to cause pump light to be incident on the first cell region, a second optical system configured to cause the pump light having passed through the first cell region to be incident on the second cell region, a third optical system configured to cause first probe light to be incident on the first cell region, a fourth optical system configured to cause second probe light to be incident on the second cell region, detection portions configured to detect the first probe light having passed through the first cell region and the second probe light having passed through the second cell region, and a deriving portion configured to derive an intensity of a magnetic field.

Optically pumped magnetometer having lasers and optical systems used to derive an intensity of a magnetic field

An optically pumped magnetometerincludes: a cell; a pump laserthat emits pump light; one or more pump light mirrors that cause the pump light guided in a first direction; a probe laserthat emits probe light; a splitting unitthat splits the probe light into multiple light components; one or more probe light mirrors that cause each of the probe light components guided in a second direction, which is a direction perpendicular to the first direction; a detection unit that detects each of the probe light components perpendicular to the pump light inside the cell; and a derivation unit that derives a magnetic field corresponding to a region where each of the probe light components and the pump light are perpendicular to each other based on a detection result of the detection unit.

Optically pumped magnetometer having reduced footprint

A magnetoencephalograph Mincludes: multiple pump-probe type optically pumped magnetometersA; a bias magnetic field forming coilfor applying a bias magnetic field in the same direction as a direction of pump light of each of the multiple pump-probe type optically pumped magnetometersA and in a direction approximately parallel to a scalp; a control devicethat determines a current for the bias magnetic field forming coil and outputs a control signal corresponding to the determined current; and a coil power supplythat outputs a current to the bias magnetic field forming coil in response to the control signal output from the control device.

Magnetoencephalograph

A cell for a optically pumped magnetic sensor measures magnetic field by setting alkali metal atoms to a predetermined excitation state by a pump beam and detecting the excitation state by a probe beam. The cell is provided with a glass substrate which seals the alkali metal atoms and an enclosing gas and transmits the pump beam and the probe beam and a coating layer provided on an inner surface of the glass substrate. The coating layer is made of an inorganic material.

Cell for optically pumped magnetic sensor

Provided is an optically pumped atomic magnetometer that can separate and acquire magnetic information of spatially different places at the same time by one probe beam. The optically pumped atomic magnetometer includes a cell containing alkali metal atoms, a pump beam optical system introducing pump beams including circularly polarized light component to different locations of the cell, a probe beam optical system introducing a probe beam including linearly polarized light component to the cell, a detection unit detecting a signal reflecting a rotation angle of a plane of polarization of the probe beam after intersecting with the pump beams, and an information acquisition unit acquiring information related to a magnetic field intensity of each of the different locations from the detected signal. The pump beam optical system includes a modulation unit modulating the pump beams so that one of frequencies and phases of the pump beams is different.

Optically pumped atomic magnetometer and magnetic sensing method

There is provided an optically pumped magnetometer, in which a pump light having a first wavelength to spin-polarize a first alkali-metal atom group is made to enter a cell containing the first alkali-metal atom group and a second alkali-metal atom group interacting via spin exchange with the first alkali-metal atom group, a probe light having a second wavelength different from the first wavelength to measure spin polarization of the second alkali-metal atom group is made to enter the cell to form the same optical axis as the pump light, a wavelength discrimination unit is provided to discriminate between the pump light and the probe light that passed through the cell depending on a different in wavelength, and the rotation angle of a polarization plane of the probe light that passed through the cell is measured so that the degree of flexibility of the device layout can be increased.

Optically pumped magnetometer

A gradiometer in which a probe beam for reading sequentially passes through two magnetic field measurement regions to obtain signals according to magnetic flux densities of the respective regions is formed using an optically pumped magnetometer. In particular, in a gradiometer using a high sensitivity optically pumped magnetometer, a geometric arrangement enabling obtainment of a large signal from a dipole moment as a signal source is defined.

Magnetic gradiometer and magnetic sensing method

An optical pumping magnetometer is provided that is capable of improving the response of the magnetometer with respect to a magnetic field that varies with a period shorter than the transverse relaxation time of electron spin of an alkali metal atom.

Optical pumping magnetometer and magnetic sensing method

An optically pumped magnetometer and a magnetic sensing method acquire information as to strengths of magnetic fields in two different directions. A pump light having a circularly polarized component, first probe light having a liner polarized component and second probe light having a linearly polarized component are emitted to a cell containing a group of alkali metal atoms so as to form a crossing region A magnetic field applying unit applies a static magnetic field in a direction of the pump light incident on the crossing region during the emission of the pump light, the first probe light and the second probe light. And, information as to strengths of magnetic fields in two different directions perpendicular to the direction of the static magnetic field in the cell from the rotation angles of a polarization planes of the first and second probe lights during passage through the cell is calculated.

Optically pumped magnetometer and magnetic sensing method

An atomic magnetometer includes a cell containing an atomic group, a pump light source, a probe light source, a mirror, and a detector. The cell is disposed between the pump light source and the mirror and between the probe light source and the detector. A pump beam emitted from the pump light source is circularly polarized light. The pump beam passes through the cell and is reflected by the mirror and then passes through the cell again. The probe beam emitted from the probe light source is linearly polarized light. An optical path of the probe beam is parallel to the plane of incidence of the pump beam and is also parallel to the surface of the mirror. The optical path of the probe beam crosses the optical path of the pump beam in the cell. The probe beam which has passed through the cell enters the detector.

Growing community of inventors

Kyoto, Japan

Tetsuo Kobayashi