ELECTROMAGNET CURRENT CONSTRAINTS
In some implementations, a system includes: a housing having a bore in which a subject to be imaged is placed; a main magnet accommodated by the housing and configured to generate a substantially uniform magnetic field within the bore; an N electromagnet comprising a conductive member that includes a first set of one or more non-conductive paths that define at least one conductive channel and a second set of one or more non-conductive paths that, when an electric current is applied to the electromagnet, constrain the electric current along a defined portion of the at least one conductive channel; and a power amplifier configured to apply an electric current to the electromagnet.
1 . A magnetic resonance imaging system comprising:
a housing having a bore in which a subject to be imaged is placed;
a main magnet accommodated by the housing and configured to generate a substantially uniform magnetic field within the bore;
an electromagnet comprising a conductive member that includes a first set of one or more non-conductive paths that define at least one conductive channel and a second set of one or more non-conductive paths that, when an electric current is applied to the electromagnet, constrain the electric current along a defined portion of the at least one conductive channel; and
a power amplifier configured to apply an electric current to the electromagnet.
2 . The magnetic resonance imaging system of claim 1 , wherein the second set of non-conductive paths are included in a location on the conductive member corresponding to the center of a gradient coil pattern of the electromagnet.
3 . The magnetic resonance imaging system of claim 1 , wherein the second set of non-conductive paths are included in a location on the conductive member corresponding to the edges of a gradient coil pattern of the electromagnet.
4 . The magnetic resonance imaging system of claim 1 , wherein the conductive member is a metal sheet.
5 . The magnetic resonance imaging system of claim 1 , wherein the first set of non-conductive paths are recesses in the conductive member from which conductive material has been removed.
6 . The magnetic resonance imaging system of claim 5 , wherein the second set of non-conductive paths are recesses in the conductive member from which conductive material has been removed.
7 . The magnetic resonance imaging system of claim 1 , wherein the second set of non-conductive paths are transverse to the first set of non-conductive paths.
8 . The magnetic resonance imaging system of claim 7 , wherein the second set of non-conductive paths are substantially perpendicular to the first set of non-conductive paths.
9 . The magnetic resonance imaging system of claim 1 wherein the defined portion of the at least one conductive channel is a portion of the conductive channel through which the electric current was assumed to flow when the electromagnet was designed.
10 . The magnetic resonance imaging system of claim 1 wherein the defined portion of the at least one conductive channel is a center portion of the conductive channel.
11 . The magnetic resonance imaging system of claim 1 , comprising at least one electrical connector connected in a series circuit with the electromagnet, the electrical connector including at least one conductive channel and a set of one or more non-conductive paths that, when an electric current is applied to the electromagnet, constrain electric current through the electrical connector along a defined portion of the at least one conductive channel of the electrical connector.
12 . A method of forming a magnetic resonance imaging system, the method comprising:
forming an electromagnet, wherein forming the electromagnet includes:
forming, in a conductive member, a first set of one or more non-conductive paths that define at least one conductive channel;
determining a portion of the at least one conductive channel to which electric current is to be constrained when electric current is applied to the at least one conductive channel;
forming, in the conductor, a second set of one or more non-conductive paths that constrain the electric current along the determined portion of the at least one conductive channel when electric current is applied to the at least one conductive channel;
coupling the electromagnet to a power amplifier configured to apply an electric current to the electromagnet;
assembling the electromagnet and power amplifier with a housing having a bore in which a subject to be imaged is placed and a main magnet accommodated by the housing and configured to generate a substantially uniform magnetic field within the bore.
13 . The method of claim 12 , wherein forming, in the conductor, a second set of one or more non-conductive paths includes forming one or more constraint cuts in a location on the conductive member corresponding to the center of the gradient coil pattern of the electromagnet.
14 . The method of claim 12 , wherein forming, in the conductor, a second set of one or more non-conductive paths includes forming one or more constraint cuts included in a conductive member on the electromagnet corresponding to the center of a gradient coil pattern of the electromagnet.
15 . The method of claim 12 , wherein forming, in the conductor, the first set of one or more non-conductive paths includes forming recesses in the conductive member by removing conductive material.
16 . The method of claim 15 , wherein forming, in the conductor, the second set of one or more non-conductive paths includes forming recesses in the conductive member by removing conductive material.
17 . The method of claim 16 , wherein forming, in the conductor, the second set of one or more non-conductive paths includes filling the recesses in the conductive member with electrical insulation material.
18 . The method of claim 12 , wherein forming, in the conductor, the second set of one or more non-conductive paths includes forming the second set of non-conductive paths transverse to the first set of non-conductive paths.
19 . The method of claim 18 , wherein forming, in the conductor, the second set of one or more non-conductive paths includes forming the second set of non-conductive paths perpendicular to the first set of non-conductive paths.
20 . The method of claim 12 wherein the portion of the at least one conductive channel to which electric current is to be constrained is a portion of the conductive channel through which the electric current was assumed to flow when the electromagnet was designed.