| US 7,576,540 B2 | ||
| Gradient coil and magnetic resonance imaging apparatus using the same | ||
| Mitsushi Abe, Hitachinaka (Japan); Yukinobu Imamura, Hitachi (Japan); and Takeshi Yatsuo, Kashiwa (Japan) | ||
| Assigned to Hitachi Medical Corporation, Tokyo (Japan) | ||
| Filed on Aug. 24, 2007, as Appl. No. 11/844,519. | ||
| Claims priority of application No. 2006-259868 (JP), filed on Sep. 26, 2006. | ||
| Prior Publication US 2008/0074112 A1, Mar. 27, 2008 | ||
| Int. Cl. G01V 3/00 (2006.01) | ||
| U.S. Cl. 324—318 | 14 Claims |
| 1. A gradient coil that is used for an open type magnetic resonance imaging apparatus and adapted to encode information on
the spatial position of a subject into a nuclear magnetic resonance signal, the gradient coil comprising:
a primary gradient coil that generates a gradient magnetic field in an imaging area; and
a shielded gradient coil that is placed on the side opposite to the imaging area relative to the primary gradient coil and
cancels the gradient magnetic field that has been generated by the primary gradient coil;
wherein the shielded gradient coil has a first area that includes a central axis perpendicularly extending through a central
portion of the imaging area and a second area that is located at an outer periphery of the first area, the second area being
bent to the side of the imaging area at an angle larger than the first area, the shielded gradient coil having a plurality
of annular conductors that are spirally arranged, the plurality of annular conductors being arranged so that a number of the
annular conductors that are each partially located in the second area is larger than a number of the annular conductors that
are located only in the first area.
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