# US 2013/0154636 A1 · Magnetic resonance imaging apparatus, magnetic field adjustment implement for magnetic resonance imaging apparatus, magnetic resonance imaging method, and method of adjusting magnetic field for magnetic resonance imaging apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0154636 A1 - Document ID: US20130154636A1 - Status: Published application - Kind: A1 - Application number: 13/766,831 - Filed: 2013-02-14 - Published: 2013-06-20 - Earliest claimed: 2011-05-10 - Assignees: Toshiba Medical Systems Corporation; Kabushiki Kaisha Toshiba - Inventors: Shohei TAKAMI; Yoshitomo SAKAKURA; Kazuto NOGAMI; Hidekazu TANAKA - Web page: https://patentgrep.com/patent/US20130154636A1 ## CPC - G01R 33/421: of main or gradient magnetic field - G01R 33/3873: using ferromagnetic bodies {; Passive shimming} - G01R 33/3875: using correction coil assemblies, e.g. active shimming - A61B 5/0046: {Arrangements of imaging apparatus in a room, e.g. room provided with shielding or for improved access to apparatus} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract According to one embodiment, a magnetic field adjustment implement for a magnetic resonance imaging apparatus includes a magnetic field adjustment unit and a placing unit. The magnetic field adjustment unit is configured to improve a uniformity of a static magnetic field formed by a magnet of the magnetic resonance imaging apparatus. The static magnetic field is formed under an influence of a circumstance in a shield room in which the magnet is placed. The magnetic field adjustment is placed outside the magnet. The placing unit is configured to place the magnetic field adjustment unit outside the magnet. ## Claims ### Claim 1 A magnetic field adjustment implement for a magnetic resonance imaging apparatus comprising: a magnetic field adjustment unit configured to improve a uniformity of a static magnetic field formed by a magnet of the magnetic resonance imaging apparatus, the static magnetic field being formed under an influence of a circumstance in a shield room in which the magnet is placed, the magnetic field adjustment being placed outside the magnet; and a placing unit configured to place said magnetic field adjustment unit outside the magnet. ### Claim 2 (depends on 1) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 1, wherein said placing unit is configured to place said magnetic field adjustment unit in a bed side outside an acquisition region of magnetic resonance signals, the acquisition region being formed in the magnet. ### Claim 3 (depends on 1) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 1, wherein said placing unit is configured to place said magnetic field adjustment unit in a side opposite to a bed, the side being outside an acquisition region of magnetic resonance signals, the acquisition region being formed in the magnet. ### Claim 4 (depends on 1) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 1, wherein said magnetic field adjustment unit uses a coil configured to improve the uniformity of the static magnetic field. ### Claim 5 (depends on 1) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 1, wherein said magnetic field adjustment unit uses a ferromagnetic substance configured to improve the uniformity of the static magnetic field. ### Claim 6 (depends on 5) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 5, wherein said placing unit is configured to place the ferromagnetic substance to a bed. ### Claim 7 (depends on 4) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 4, wherein said placing unit is configured to place the coil in a side opposite to a bed, the coil being placed outside an acquisition region of magnetic resonance signals, the acquisition region being formed in the magnet. ### Claim 8 (depends on 1) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 1, wherein said magnetic field adjustment unit has: a coil configured to improve the uniformity of the static magnetic field; a storage unit configured to store current values to be supplied to said coil according to placed objects in the shield room, the objects each influencing the static magnetic field; and a current supply unit configured to supply a current to said coil, the current having a current value read from said storage unit. ### Claim 9 (depends on 1) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 1, wherein said magnetic field adjustment unit has a coil which can be divided with a connector, the coil improving the uniformity of the static magnetic field, and said placing unit is configured to place said coil so as to set a top plate of a bed inside said coil. ### Claim 10 (depends on 1) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 1, wherein said magnetic field adjustment unit has a coil configured to improve the uniformity of the static magnetic field; and said placing unit is configured to fix said coil inside a gantry in which the magnet is built. ### Claim 11 (depends on 1) The magnetic field adjustment implement for the magnetic resonance imaging apparatus of claim 1, wherein said magnetic field adjustment unit has a ferromagnetic substance configured to form a magnetic circuit with the shield room by leading magnetic flux lines to the shield room, the magnetic flux lines being formed by the magnet and passing inside said ferromagnetic substance, the magnetic circuit being formed in a bed side outside an acquisition region of magnetic resonance signals formed in the magnet. ### Claim 12 A magnetic resonance imaging apparatus comprising: an imaging unit configured to perform a magnetic resonance imaging by forming a static magnetic field with a magnet and acquiring magnetic resonance signals from an object sent by a bed into an acquisition region of the magnetic resonance signals formed in the magnet; and a magnetic field adjustment unit configured to improve a uniformity of the static magnetic field formed under an influence of a circumstance in a shield room in which the magnet is placed, the magnetic field adjustment being placed outside the magnet. ### Claim 13 (depends on 12) The magnetic resonance imaging apparatus of claim 12, wherein said magnetic field adjustment unit has a ferromagnetic substance, the ferromagnetic substance being an element of the bed. ### Claim 14 (depends on 12) The magnetic resonance imaging apparatus of claim 12, wherein said magnetic field adjustment unit has a ferromagnetic substance on the bed. ### Claim 15 (depends on 12) The magnetic resonance imaging apparatus of claim 12, wherein said magnetic field adjustment unit has: a coil configured to improve the uniformity of the static magnetic field, the coil being placed in a side opposite to the bed and outside the acquisition region of the magnetic resonance signals; and a ferromagnetic substance placed to the bed or in a bed side, said ferromagnetic substance being a part of the bed or a part added to the bed. ### Claim 16 (depends on 12) The magnetic resonance imaging apparatus of claim 12, wherein said magnetic field adjustment unit has a ferromagnetic substance whose height is changed with a top plate of the bed so as to improve the uniformity of the static magnetic field by said ferromagnetic substance when a height of the top plate has become a height for sending the top plate into the acquisition region of the magnetic resonance signals. ### Claim 17 (depends on 12) The magnetic resonance imaging apparatus of claim 12, wherein said magnetic field adjustment unit has a ferromagnetic substance placed to the bed or in a bed side, said ferromagnetic substance being a part of the bed or a part added to the bed, the bed being configured to move a top plate with a larger torque than a magnetic force attracting the ferromagnetic substance to the magnet. ### Claim 18 A method of adjusting a magnetic field for a magnetic resonance imaging apparatus comprising: arranging a magnetic field adjustment unit outside a magnet of the magnetic resonance imaging apparatus; and improving a uniformity of a static magnetic field by the magnetic field adjustment unit, the static magnetic field being formed by the magnet, the static magnetic field being formed under an influence of a circumstance in a shield room in which the magnet is placed. ### Claim 19 A magnetic resonance imaging method comprising: performing a magnetic resonance imaging by forming a static magnetic field with a magnet and acquiring magnetic resonance signals from an object sent by a bed into an acquisition region of the magnetic resonance signals formed in the magnet; and arranging a magnetic field adjustment unit outside the magnet and improving a uniformity of the static magnetic field by the magnetic field adjustment unit, the static magnetic field being formed by the magnet, the static magnetic field being formed under an influence of a circumstance in a shield room in which the magnet is placed.