Hitachi, Ltd.

Sony Corporation

Hitachi Medical Corporation

Sony Computer Entertainment Inc.

Other

Sony Interactive Entertainment Inc.

Hitachi Engineering Co., Ltd.

Kenji Sakakibara

Hirotaka Takeshima

Hikaru Hanada

Yoshihide Wadayama

Takuya Fujikawa

Mitsushi Abe

Takeshi Yatsuo

Hiroyuki Watanabe

Kazuto Nakagawa

Hiroaki Masuda

Kiyokazu Miyazawa

Yu Togasaki

Takao Honmei

Tsutomu Yamamoto

Nobuyuki Takahashi

Takashi Sogabe

Shigeru Kakugawa

Kazuya Wakabayashi

Munetaka Tsuda

Tsuyoshi Wakuda

Katsunori Azuma

Akira Kurome

Ryuya Ando

Hisako Nagao

Akihiro Shimada

Kazuya Odagiri

Shin Hoshino

Naka Shibata

Hirofumi Motoshiromizu

Kunihito Suzuki

In order to provide a static magnetic field homogeneity adjustment method capable of reducing an arrangement amount of magnetic pieces and achieving desired magnetic field homogeneity with high accuracy in magnetic field homogeneity adjustment, there is provided a static magnetic field homogeneity adjustment method in an imaging space of computing positions of a plurality of magnetic pieces separated from the imaging space through shimming computation with respect to a static magnetic field in the imaging space generated by a magnetic field generation device, and disposing the plurality of magnetic pieces at the positions obtained through the shimming computation, the method including an adjustment step of imposing restriction that a polarity of a magnetic field distribution generated in the imaging space by the magnetic pieces disposed at the positions is either positive or negative during the shimming computation, and adjusting the static magnetic field homogeneity.

Magnetic resonance imaging apparatus, static magnetic field homogeneity adjustment method, program, and computer

In the present invention, a current plane which is virtually disposed and surrounds a measurement position is assumed from magnetic field measurement values, and a current distribution (or magnetic moment distribution) which mimics a measured magnetic field is reproduced with current potentials. This is used to perform shimming calculation by a truncated singular value decomposition method with discrete shim trays that are actually used and ideal virtual continuous shim trays to carry out shimming under conditions for shimming having a uniformity that is close to ideal shimming.

Magnetic field adjusting method

The present invention provides a shimming method in which an electric current surface that is virtually placed so as to surround a measurement position is assumed from a magnetic field measurement value, in which an electric current distribution that reproduces a measurement magnetic field is reproduced through an electric current potential, and in which the reproduced magnetic field distribution is used. A magnetic moment or an electric current distribution that reproduces a magnetic field distribution obtained by a magnetic field measurement device is estimated on a predetermined closed surface, and, from the estimated magnetic moment or electric current distribution, a magnetic field distribution of an arbitrary point that exists in the closed surface is estimated. Then, on the basis of the estimated magnetic field distribution, a shim magnetic body distribution that produces a correction magnetic field for correcting the magnetic field distribution at the arbitrary point is output.

Shimming system and shimming method including a sensor unit having a pluraly of magnetic field sensors

A magnetic moment arrangement calculation method for magnetic field adjustment by combining correction of a component of a low-order mode with correction of a component of a high-order mode among the eigenmodes so as to calculate arrangement of the magnetic moment for approximately correcting the error magnetic field distribution, in which the low-order mode is an eigenmode group from the first of eigenmode numbers assigned to respective eigenmodes in the magnitude order of singular values to an eigenmode number specified by a first threshold value, in which the high-order mode is an eigenmode group with an eigenmode number more than the first threshold value, and in which a correction amount of the component of the high-order mode is smaller than a correction amount of the component of the low-order mode.

Magnetic moment arrangement calculation method for magnetic field adjustment, magnetic field adjustment device and program

Even if there is a restriction in an amount of magnetic pieces which can be disposed at each position in a shim tray, a distribution of a static magnetic field is measured so that an error magnetic field between the distribution of the static magnetic field and a target magnetic field is calculated, and respective reachable magnetic field homogeneities in a case where the magnetic pieces are disposed at one or more of the plurality of positions in the shim tray are calculated while changing the target magnetic field. The target magnetic field is selected in which an amount of magnetic pieces at each of the positions in the shim tray is equal to or less than a predetermined upper limit value, and the reachable magnetic field homogeneity is equal to or less than a predetermined value.

Magnetic field homogeneity adjustment method, magnetic field homogeneity adjustment program and magnetic field homogeneity adjustment device

Static magnetic field inhomogeneity is reduced by measuring inhomogeneity of a static magnetic field distribution in an imaging space, evaluating a distribution of a correction magnetic field that should be generated by a correction magnetic field generating unit disposed in the vicinity of the imaging space based on the measured static magnetic field distribution, reducing the electric current value of the superconducting coil to a predetermined (greater than zero) low current value smaller than a rated current value, notifying an operator to set a correction magnetic field of the correction magnetic field generating unit to the correction magnetic field evaluated by calculation in a state where an electric current at the low current value is flowing in the superconducting coil and a low static magnetic field B_low is being generated, and repeating the above operations.

Magnetic resonance imaging system, static magnetic field homogeneity adjusting system, magnetic field homogeneity adjusting method, and magnetic field homogeneity adjusting program

To prevent image quality deterioration of an image due to a variable magnetic field generated by a fan motor provided in a position where a measuring magnetic field leaks, a magnetic resonance imaging apparatus has a gantry including a static magnetic field generating magnet; a gradient magnetic field generating coil; and an irradiation coil, a table for placing the object, and an input/output device including a display device and is provided with at least a pair of cooling fan motors arranged almost symmetrically to the central axis that extends along the long-axis direction of the cylindrical space and is located in the center in the horizontal direction of the static magnetic field generating magnet or the vertical plane passing through the central axis.

Magnetic resonance imaging apparatus and operating method of cooling fan motor of magnetic resonance imaging apparatus

There is provided an MRI apparatus including a superconducting magnet that includes a refrigerant container and a superconducting coil, a cryogenic cooling system with which the superconducting magnet is provided, and a controller that controls the operation of the cryogenic cooling system. The cryogenic cooling system includes a cold head, a cryo-cooler, a compressor that supplies a compressed gas to the cryo-cooler, and a detection unit that detects the pressure in the refrigerant container, the refrigerant container being provided with the cold head, the cryo-cooler, the compressor, and the detection unit. An upper limit value of the maximum number of times of halts of the compressor within a predetermined period of time is set in advance. The controller intermittently halts the compressor within a range in which the pressure detected by the detection unit is equal to or lower than a predetermined upper limit value and performs control such that the number of times of halts of the compressor within the predetermined period of time reaches the upper limit value of the maximum number of times of halts.

Magnetic resonance imaging apparatus, and control apparatus of cryogenic cooling system and control method thereof

In order to avoid the duplication of the period and cost required for magnetic field adjustment, minimize the magnetic field adjustment period in a final installation site, and achieve highly efficient magnetic field adjustment of a magnet, a method for adjusting the homogeneity of a static magnetic field generated in a measurement space by a static magnetic field generation means by disposing magnetic field correction means for generating a corrected magnetic field with respect to the static magnetic field comprises: a step for measuring the static magnetic field generated by the static magnetic field generation means; a step for expanding the spatial distribution of the measured static magnetic field in a series; a first magnetic field adjustment step for correcting a high-order term irregular magnetic field components expanded in a series; and a second step for adjusting a low-order irregular magnetic field component, the second step being performed after the first adjustment step.

Method for adjusting static magnetic field homogeneity, static magnetic field generation device for magnetic resonance imaging, magnetic field adjustment system, and program

A first antenna () is disposed closer to a rear touch panel () than to a display panel () in the front-rear direction of a housing (). The first antenna () is disposed so as to be offset with respect to the rear touch panel () in a direction perpendicular to the front-rear direction of the housing () so that at least a part of the first antenna () does not overlap the rear touch panel () in the front-rear direction of the housing (). With such a structure, the display panel and touch panel are provided at the front surface and rear surface, respectively, and good reception sensitivity can be obtained.

Portable type electronic device, portable type electronic device group, and method of manufacturing portable type electronic device

An operation member and an electronic device capable of maintaining operability while enhancing cushioning properties provided in the outer surface of an operation member are provided. An operation stick has a cushion portion and a base portion on which the cushion portion is placed. The base portion is supported to be movable. The base portion has a frame portion surrounding the outer periphery of the cushion portion. The base portion and the frame portion are formed of a material having a higher rigidity than that of the material of the cushion portion.

Operation member provided in electronic device, and electronic device

An electronic device () has hold parts (R,L) constituting respective right and left side parts of the electronic deviceand being available to be held by a user. Operating sticks (R,L) are provided on the respective hold parts (R,L). A rear touch panel () is provided on the rear surface of the electronic device (). The rear touch panel () is provided in at least an area located further upward than a positions P opposite from the operation sticks (R,L). This layout of the rear touch panel () allows a user to smoothly operate the rear touch panel () while holding the hold parts of the electronic device.

Portable electronic device

An electronic device includes a front panel made of resin. The front panel is disposed on the front side of an organic electroluminescent display panel and functions as the front surface of the electronic device; and an adhesive agent layer formed between the organic electroluminescent display panel and the front panel. The organic electroluminescent display panel is fixed to the front panel via the adhesive agent layer. This structure is able to reduce a load applied to the organic electroluminescent display panel and ensure shock resistance for the organic electroluminescent display panel.

Growing community of inventors

Tokyo, Japan

Kenji Sakakibara