Hitachi, Ltd.

Hitachi Medical Corporation

Other

Hokkaido University

Hitachi Car Engineering Co., Ltd.

Ryuya Ando

Mitsushi Abe

Manabu Aoki

Takeshi Nakayama

Makoto Yamakado

Noriyuki Maekawa

Kiyotaka Ogura

Atsushi Sekine

Hiroyuki Watanabe

Yusuke Vincent Fujii

Kikuo Umegaki

Tsutomu Yamamoto

Ryoji Nakagawa

Kenji Sakakibara

Takeshi Kawamura

Takeshi Yatsuo

Takeo Nemoto

Masanao Terada

Yukinobu Imamura

Taeko Matsuura

Hiroki Shirato

Shinichi Shimizu

Tomoo Chiba

Akihisa Miyazoe

Yoshiya Higuchi

Yukihiro Murata

Takuro Honda

A particle therapy system includes an acceleratorwhich generates a particle beam for extraction, an irradiation apparatuswhich irradiates the particle beam to an irradiation target, a gantrywhich rotates together with the irradiation apparatus, and an MRI apparatuswhich rotates together with the gantry. The MRI apparatusincludes a magnetic circuit composed of an iron coreand a plurality of coilsserving as a magnetic flux source. The iron coreincludes two oppositely disposed magnetic polesA andB, and a return yokefor connecting the magnetic polesA andB. The magnetic polesA,B have cavitiesA,B. The particle beam passing through the cavityA is irradiated to the irradiation target

Particle therapy system

A computer executes: calculating a first volume distribution (v.d.) of magnetic materials on a shim tray, based on a first magnetic field strength distribution (m.f.s.d.) in a magnetic field space (S); acquiring a first composite distribution (c.d.) representing a volume by addition of volumes of magnetic materials for each region of the shim tray, and positions of the regions (S); calculating a virtual m.f.s.d. created by magnetic materials supposed to be arranged as in the first c.d. (S); calculating a second m.f.s.d. by addition of the first m.f.s.d. and the virtual m.f.s.d. (S); calculating a second v.d. of magnetic materials on the shim tray, based on the second m.f.s.d. (S); acquiring a second c.d. representing a volume by addition of volumes of magnetic materials for each region, and positions of the regions (S); and displaying the positions of regions and the volumes in the first c.d. and second c.d. (S).

Magnetic field homogeneity adjustment method, magnet device, and magnetic resonance imaging apparatus

This superconducting magnet includes: a superconducting coil that is formed by winding a first superconducting wire rod; a second superconducting wire rod, which is disposed by being thermally in contact with and electrically insulated from the superconducting coil, and which has a superconducting transition temperature that is lower than that of the first superconducting wire rod; voltage terminals that are disposed at a plurality of areas of the second superconducting wire rod; a voltmeter connected to the voltage terminals; and a switch circuit connected to the voltmeter. The switch circuit interrupts a current when receiving an output from the voltmeter, the current being one that is to be supplied to the superconducting coil.

Superconducting magnet

In a gradient magnetic field coil device including: a plurality of main coils generating in an imaging region of a magnetic field resonance imaging device a magnetic field distribution in which an intensity linearly inclines; and a plurality of shield coils, arranged on an opposite side of the imaging region across the main coils, suppressing residual magnetic field generated by the main coils on the opposite side. The plurality of main coils and the plurality of shield coils are connected in series. The device further includes a plurality of current adjusting devices, connected to the shield coils in parallel, independently adjusting currents flowing through the shield coils, respectively, to enhance symmetry of the residual magnetic field. The gradient magnetic field coil device is provided which can suppress generation of eddy current magnetic field even if there is a relative position deviation between the main coils and shield coils.

Gradient magnetic field coil device, adjustment method therefor, and magnetic resonance imaging apparatus

A superconducting magnet device is configured to include: a refrigerant circulation flowpath in which a refrigerant (R) circulates; a refrigerator for cooling vapor of the refrigerant (R) in the refrigerant circulation flowpath; a superconducting coil cooled by the circulating refrigerant (R); a protective resistor thermally contacting the superconducting coil and having an internal space (S); a high-boiling-point refrigerant supply section for supplying a high-boiling-point refrigerant having a higher boiling point than the refrigerant (R) and frozen by the refrigerant (R) to the internal space (S) in the protective resistor; and a vacuum insulating container for at least accommodating the refrigerant circulation flowpath, the superconducting coil, and the protective resistor.

Superconducting electromagnet device, cooling method therefor, and magnetic resonance imaging device

A superconducting magnet apparatus includes: a bobbin around which a superconducting coil is wound, the bobbin serving as a protective resistor; a persistent current switch for supplying a persistent current to the superconducting coil; a first closed circuit with the superconducting coil and the persistent current switch connected in series to the coil; and a second closed circuit with the superconducting coil and the bobbin connected in series to the coil.

Superconducting magnet apparatus

A measured error magnetic field distribution is divided into eigen-mode components obtained by a singular decomposition and iron piece arrangements corresponding to respective modes are combined and arranged on a shim-tray. An eigen-mode to be corrected is selected in accordance with an attainable magnetic field accuracy (homogeneity) and appropriateness of arranged volume of the iron pieces. Because the adjustment can be made with the attainable magnetic field accuracy (homogeneity) being known, an erroneous adjustment can also be known, and the adjustment is automatically done during repeated adjustments. As a result, an apparatus with a high accuracy can be provided. In addition, there is an advantageous effect of being able to detect a poor magnet earlier by checking the attainable homogeneity.

Magnetic field shimming adjustment: reducing magnetic distribution errors by obtaining current potential distributions of MRI apparatus

The magnetic field homogeneity adjusting device () is characterized by comprising a magnetic field distribution measuring unit () for measuring the magnetic field distribution in the magnetic field space, a temperature variation calculating unit () for calculating the temperature variation of the ferromagnetic bodies needed to improve the homogeneity of the magnetic field space based on the measured magnetic field distribution, and a temperature control unit () for setting a temperature control value of the ferromagnetic bodies according to the calculated temperature variation.

Superconductive magnetic device, magnetic resonance imaging apparatus and magnetic field inhomogeneity compensation method

The active shield superconducting electromagnet apparatus includes: a main switching circuit in which first and second main coils, first and second shield coils, and a first superconducting persistent current switch are connected in series; a sub switching circuit in which a bypass circuit, in which a superconducting fault current limiter and a second superconducting persistent current switch are connected in series, are connected to a series circuit of the first main coil and the second main coil in parallel; a first closed circuit in which at least one of the first main coil and the first shield coil, and a first quench protection circuit are connected in series; and a second closed circuit in which one of the second main coil and the second shield coil, and a second quench protection circuit are connected in series.

Active shield superconducting electromagnet apparatus and magnetic resonance imaging system

A superconducting magnet includes: a superconducting coil for generating a static magnetic field; a refrigerant container for containing the superconducting coil and a refrigerant; a vacuum container for holding the refrigerant container in a vacuum state; a radiation shield between the refrigerant container and the vacuum container; a refrigerator for re-liquidfying the refrigerant; and a dynamic magnetic field shield. The refrigerator includes: first and second regenerative refrigerants. The dynamic magnetic field shield is an electric good conductor and arranged around the first regenerative refrigerant along a motion axis of the first regenerative refrigerant, wherein a direction of the motion axis is aligned with a direction of a magnetic force line of the static magnetic field at the first regenerative refrigerant.

Superconducting magnet with refrigerator and magnetic resonance imaging apparatus using the same

A magnet device has main coils in a pair positioned facing each other to form a static magnetic field space in between and external magnetic flux shielding coils placed coaxially to the main coils. The external magnetic flux shielding coils have a first coil group having a small coefficient of coil coupling and a second coil group having a coefficient of coil coupling greater than that of the first coil group. The first coil group is connected in series to the second coil group. External magnetic flux entering the magnetic field imaging space formed by main coils in a pair positioned facing each other is effectively warded off.

Magnet device

An object of the present invention is to provide a MRI superconductive magnet enables sharp images representing patients' health states to be produced. [Means for Achieving the Object] A MRI superconductive magnet having a superconductive coil, a liquid vessel of liquid helium used to cool the superconductive coil, a heat shield to accommodate the liquid vessel therein, a vacuum chamber to accommodate the heat shield therein, a load supporting body for supporting the superconductive coil from the vacuum chamber and securing the superconductive coil, a second cold part of a multi-stage refrigerator for cooling a heat exchanger to condense evaporated helium gas, and a first cold part of the multi-stage refrigerator for cooling the heat shield, wherein a magnetic shield is provided from the first cold part of the multi-stage refrigerator to an outer periphery of the second cold part of the multi-stage refrigerator.

MRI superconductive magnet

A magnetic resonance imaging apparatus and the magnet apparatus thereof comprise plural pairs of magnetic field generation sources, arranged face to face with each other, for forming a magnetic field space; and magnetic field homogeneity adjusting apparatusesandfor providing homogeneity adjustment of the magnetic field formed in the magnetic field space. The magnetic field homogeneity adjusting apparatusesandcontain a plurality of tapped holesfor installing a magnetic field homogeneity adjusting memberof smaller volume in a plate-formed tray made of a non-magnetic substance; and a plurality of mountsfor installing the magnetic field homogeneity adjusting memberof greater volume, these mounts being formed over the area containing a plurality of through-holes for permitting installation of a magnetic field homogeneity adjusting memberof smaller volume, whereby major magnetic field adjusting work can be performed independently of minor magnetic field adjusting work.

Magnetic resonance imaging apparatus and magnet apparatus therefor

A press-machined fuel induction pipe, a hollow tubular type of fixed corewith a flange at its upper end, and a nozzle holderthat was press-machined into a slender tubular shape and has an orifice plate equipped with a valve seat at the lower end of the nozzle holder, are connected by welding. The upper inner surface of nozzle holderand the outer surface of fixed coreare welded after being press-fit. A movable coreand a valve bodyare connected to the welded assembly via a pointhaving a spring function. On the outer surface of nozzle holderis provided an electromagnetic coil, the outside of which is provided with a tubular yokewhose upper end is connected by welding to the flangeof fixed coreand whose lower end is press-fit on the outer surface of nozzle holder

Electromagnetic fuel injection valve

A press-machined fuel induction pipe a hollow tubular type of fixed core with a flange at its upper end, and a nozzle holder that was press-machined into a slender tubular shape and has an orifice plate equipped with a valve seat at the lower end of the nozzle holder, are connected by welding. The upper inner surface of nozzle holder and the outer surface of fixed core are welded after being press-fit. A movable core and a valve body are connected to the welded assembly via a point having a spring function. On the outer surface of nozzle holder is provided an electromagnetic coil the outside of which is provided with a tubular yoke whose upper end is connected by welding to the flange of fixed core and whose lower end is press-fit on the outer surface of nozzle holder

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Hitachi, Japan

Ryuya Ando