Magnetic stimulation coils and ferromagnetic components for reduced surface stimulation and improved treatment depth

Abstract

A TMS device may include treatment coils and ferromagnetic components that are configured to be disposed proximate to corresponding ones of the treatment coils. The treatment coils and ferromagnetic components of the TMS device may cooperatively generate a magnetic field that exhibits one or more characteristics that differ from those of a magnetic field that is generated by the treatment coils alone. For example, the magnetic field may exhibit lower induced electrical stimulation intensity in the cranial nerves, while substantially maintaining a penetration depth into the subject's brain. In another example, the magnetic field may exhibit increased penetration depth into the subject's brain, while substantially maintaining induced electrical stimulation intensity in the cranial nerves. The TMS device may be configured to be adjustable and/or reconfigurable, for instance with respect to the anatomy of a subject (e.g., to the shape of the subject's head).

What is claimed is: 
     
         1 . A system for treating or diagnosing a patient, the system comprising:
 a first stimulation coil and a second stimulation coil, wherein the first and second stimulation coils are circularly shaped;   a first ferromagnetic component configured to at least partially receive the first stimulation coil, and a second ferromagnetic component configured to at least partially receive the second stimulation coil; and   a control circuit in electrical communication with the first and second stimulation coils and configured to provide current to the first and second stimulation coils to generate a magnetic field in a target anatomy of a human subject;   wherein conductive windings of the first stimulation coil are centered on a first axis, and windings of the second stimulation coil are centered on a second axis, wherein the second axis is angularly offset relative to the first axis; and   wherein, when the first and second stimulation coils are configured adjacent the target anatomy of the human subject, the first and second axes pass through a common point within the target anatomy of the human subject.   
     
     
         2 . The system of  claim 1 , wherein the first and second ferromagnetic components are saucer shaped. 
     
     
         3 . The system of  claim 1 , further comprising a bridge member that is configured to support the first and second ferromagnetic components relative to each other, wherein the bridge member is movably attached to the first ferromagnetic component or the second ferromagnetic component. 
     
     
         4 . The system of  claim 3 , wherein the bridge member comprises a first portion that is attached to the first ferromagnetic component and a second portion that is attached to the second ferromagnetic component, wherein the first and second portions of the bridge member are configured to slide past each other to adjust the relative position of the first and second stimulation coils. 
     
     
         5 . The system of  claim 1 , wherein the first ferromagnetic component at least partially surrounds portions of the first stimulation coil, and the second ferromagnetic component at least partially surrounds portions of the second stimulation coil. 
     
     
         6 . The system of  claim 1 , wherein the first ferromagnetic component defines an central opening that is aligned with a central opening of the first treatment coil, and the second ferromagnetic component defines a central opening that is aligned with a central opening of the second treatment coil. 
     
     
         7 . The system of  claim 1 , wherein the first treatment coil is attached to the first ferromagnetic component and electrically isolated from the first ferromagnetic component, and the second treatment coil is attached to the second ferromagnetic component and electrically isolated from the second ferromagnetic component. 
     
     
         8 . A system for treating or diagnosing a patient, the system comprising:
 a first stimulation coil comprising a first plurality of windings, and a second stimulation coil comprising a second plurality of windings, wherein the first and second stimulation coils are circularly shaped;   a first ferromagnetic component configured to be partially received within the first stimulation coil, and a second ferromagnetic component configured to be partially received within the second stimulation coil; and   a control circuit in electrical communication with the first and second stimulation coils and configured to provide current to the first and second stimulation coils to generate a magnetic field in a target anatomy of a human subject;   wherein the first plurality of windings are centered on respective axes that are angularly offset relative to each other;   wherein the second plurality of windings are centered on respective axes that are angularly offset relative to each other; and   wherein, when the first and second stimulation coils are configured adjacent the target anatomy of the human subject, the respective axes of the first plurality of windings and the respective axes of the second plurality of windings pass through a common point within the target anatomy of the human subject.   
     
     
         9 . The system of  claim 8 , wherein respective angular offsets between adjacent ones of the respective axes of the first plurality of windings are the same, and wherein respective angular offsets between adjacent ones of the respective axes of the second plurality of windings are the same. 
     
     
         10 . The system of  claim 8 , wherein respective angular offsets between adjacent ones of the respective axes of the first plurality of windings correspond to respective angular offsets between adjacent ones of the respective axes of the second plurality of windings. 
     
     
         11 . The system of  claim 8 , wherein the first ferromagnetic component and the second ferromagnetic component define respective concave, saucer-shaped coil geometries that encircle respective portions of a head of the human subject. 
     
     
         12 . The system of  claim 8 , wherein the first ferromagnetic component at least partially surrounds portions of the first stimulation coil, and the second ferromagnetic component at least partially surrounds portions of the second stimulation coil. 
     
     
         13 . The system of  claim 8 , wherein a portion of the first ferromagnetic component is received within an aperture defined by the first stimulation coil, and a portion of the second ferromagnetic component is received within an aperture defined by the second stimulation coil. 
     
     
         14 . The system of  claim 8 , wherein the first ferromagnetic component comprises a recess that defines a shape that is similar to a corresponding winding of the first stimulation coil, and wherein the second ferromagnetic component comprises a recess that defines a shape that is similar to a corresponding winding of the second stimulation coil. 
     
     
         15 . A system for treating or diagnosing a patient, the system comprising:
 a first stimulation coil comprising a first plurality of non-concentric windings centered on respective axes, and a second stimulation coil comprising a second plurality of non-concentric windings centered on respective axes, wherein the first and second stimulation coils are circularly shaped;   a first ferromagnetic component configured to be partially received within the first stimulation coil, and a second ferromagnetic component configured to be partially received within the second stimulation coil; and   a control circuit in electrical communication with the first and second stimulation coils and configured to provide current to the first and second stimulation coils to generate a magnetic field in a target anatomy of a human subject;   wherein, when the first and second stimulation coils are configured adjacent the target anatomy of the human subject, the respective axes of the first plurality of windings and the respective axes of the second plurality of windings pass through a common point within the target anatomy of the human subject.   
     
     
         16 . The system of  claim 15 , wherein respective angular offsets between adjacent ones of the respective axes of the first plurality of windings are different, and wherein respective angular offsets between adjacent ones of the respective axes of the second plurality of windings are different. 
     
     
         17 . The system of  claim 15 , wherein respective angular offsets between adjacent ones of the respective axes of the first plurality of windings do not correspond to respective angular offsets between adjacent ones of the respective axes of the second plurality of windings. 
     
     
         18 . The system of  claim 15 , wherein the first plurality of windings are spaced closest together to each other on one side of the first stimulation coil and furthest apart from each other on an opposed side of the first stimulation coil, and wherein the second plurality of windings are spaced closest together to each other on one side of the second stimulation coil and furthest apart from each other on an opposed side of the second stimulation coil. 
     
     
         19 . The system of  claim 15 , wherein the first treatment coil is attached to the first ferromagnetic component and electrically isolated from the first ferromagnetic component, and the second treatment coil is attached to the second ferromagnetic component and electrically isolated from the second ferromagnetic component. 
     
     
         20 . The system of  claim 15 , wherein the first and second stimulation coils are configured to generate the magnetic field in a first and second hemisphere of the human subject's brain.