Patent ID: 7576540

Claim:
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.