| 摘要 |
PURPOSE:To prevent the generation of eddy currents in electric conductor having planar spiral shapes constituting a gradient magnetic field generator for an MRI apparatus by providing these electric conductors with nonconductive parts so as to divide current conducting paths to a plurality without cutting these paths. CONSTITUTION:The gradient magnetic field coil 30 of the gradient magnetic field generator consists of the electric conductors 31. The shapes of the electric conductors 31 exclusive of an outer peripheral part are regulated by spacings 33 between the electric conductors 31 to form the current conducting paths from the points near the center on the left side through the respective spirals on the right side and the left side to the points near the center on the right side. The broad parts of the electric conductors 31 are provided with the non-conducting paths 34 so as to divide the current conducting paths to two without cutting the current conducting paths. As a result, the areas of the electric conductors have no more wide parts and the effective area with respect to generation of the eddy currents are nearly halved. The generation of the eddy currents is thus prevented. Cutting of the currents intrinsic to the gradient magnetic field coil does not arise and the coil patters do not substantially change and, therefore, the coil characteristics do not change.
|
