Coil device and transcranial magnetic stimulation system
A coil device for transcranial magnetic stimulation treatment, that generates an overcurrent uniformly across a wide range inside the head of a patient. The coil device includes a winding frame and a coil. A cylindrical surface of the winding frame has: an inner surface section arranged near the cranial surface during use; and an outer surface section forming a convex curved surface protruding towards the outside of the cylindrical surface, relative to a first direction parallel to a neutral axis and a second direction orthogonal to the first direction. The neutral axis draws a convex curve.
1. A coil device used in a transcranial magnetic stimulation treatment that is configured to be placed on or near a head surface to stimulate neurons by inducing an eddy current in the brain through electromagnetic induction, the coil device comprising:
a spool having a neutral axis acquired by connecting centers of gravity in transverse cross sections and a tubular surface surrounding the neutral axis; and
a coil made up of a conductive wire wound on the tubular surface around the neutral axis,
the tubular surface having
an inner surface portion configured to be located close to the head surface during use, and
an outer surface portion forming a convex curved surface protruding outward of the tubular surface with respect to a first direction parallel to the neutral axis and a second direction orthogonal to the first direction,
the coil having end-part transverse cross sections on one end side and an other end side of the neutral axis smaller than a center-part transverse cross section located at a center between the one end side and the other end side,
the neutral axis forming a convex curve protruding from the inner surface portion toward the outer surface portion.
2. The coil device according to claim 1 , wherein the inner surface portion is a curved surface recessed in a concave shape toward an inside of the tubular surface.
3. The coil device according to claim 1 , wherein the inner surface portion is a flat surface.
4. The coil device according to claim 1 , wherein the coil device has an outer housing portion covering a coil portion located on the outer surface portion.
5. The coil device according to claim 1 , wherein the coil device has an inner housing portion covering a coil portion located on the inner surface portion.
6. The coil device according to claim 5 , wherein the inner housing portion has an outer surface that is a curved surface recessed in a concave shape toward an inside of the tubular surface.
7. The coil device according to claim 1 , wherein the tubular surface has end-part transverse cross sections on one end side and an other end side of the neutral axis smaller than a center-part transverse cross section located at a center between the one end side and the other end side.
8. The coil device according to claim 7 , wherein the transverse cross sections of the tubular surface are configured to become gradually smaller from the center-part transverse cross section toward the end-part transverse cross sections.
9. The coil device according to claim 1 , wherein the neutral axis is an axis passing through centroids or centers of gravity of transverse cross sections of the tubular surface.
10. The coil device according to claim 1 , wherein the spool is made up of a hollow member extending along the neutral axis.
11. The coil device according to claim 1 , wherein the spool is made up of a solid member.
12. A coil device used in a transcranial magnetic stimulation treatment that is configured to be placed on or near a head surface to stimulate neurons by inducing an eddy current in the brain through electromagnetic induction, the coil device comprising:
a spool having a neutral axis acquired by connecting centers of gravity in transverse cross sections and a tubular surface surrounding the neutral axis; and
a coil made up of a conductive wire wound on the tubular surface around the neutral axis,
the coil having end-part transverse cross sections on one end side and an other end side of the neutral axis smaller than a center-part transverse cross section located at a center between the one end side and the other end side,
the tubular surface having an inner surface portion configured to be located close to the head surface during use and an outer surface portion configured to be located away from the head surface during use, both the inner surface portion and the outer surface portion forming convex curved surfaces protruding outward.
13. A transcranial magnetic stimulation system comprising: the coil device according to claim 1 .