Coil device and magnetic field generating device

• US 8,062,204 B2
• Filed: 04/22/2005
• Issued: 11/22/2011
• Est. Priority Date: 04/23/2004
• Status: Expired due to Fees

• Current Assignee: Kanazawa University
• Original Assignee: Kanazawa University
• Inventors: Ikehata, Yoshio, Nagano, Isamu
• Primary Examiner(s): Marmor, II; Charles A
• Assistant Examiner(s): Burk; Catherine E
• Application Number:
  US11/578,951
• Publication Number:
  US 20080114429A1
• Time in Patent Office: 2,405 Days
• Field of Search: 600 9- 15, 219/632, 219/677, 174/15.1
• US Class Current: 600/13
• CPC Class Codes: A61N 1/403 for thermotherapy, e.g. hyperthermia
• CPC Class Codes: A61N 2/02 using magnetic fields produced by coils, including single turn loops or electromagnets A61N2/12 takes precedence
• CPC Class Codes: H05B 6/362 with flat coil conductors

Abstract

Problems to be solved: to provide a coil device and a magnetic field generating device with reduced energy loss that are suitable for use in the thermotherapy method.

Means for solving the problem: a coil device according to the present invention can be used in a magnetic field generating device for the thermotherapy method in which a magnetic flux is irradiated to the patient to selectively heat a specific portion of the patient. Said coil device is a bread-shaped coil device having a current path extending in the shape of a spiral in a substantially same plane, said current path comprising a hollow cylindrical member (10) of a nonmagnetic material inside which a space is formed and a plurality of conductive wires (11, 12) covered with an insulation material on the peripheries thereof. In the present invention, the current path comprising a plurality of conductive wires covered with an insulation material which are arranged in a circle, energy loss caused by the skin effect and energy loss caused by the line capacity can be reduced, making it possible to generate a strong magnetic field. Also, by using the hollow cylindrical member (10), it is possible to easily configure a current path in a predetermined diameter and to inhibit increase in temperature of the coil (3) to avoid fluctuation of the resonance frequency of the resonance circuit. With this, a magnetic field generating device that is suitable for use in thermotherapy, particularly cancer therapy, can be realized.

Claims

1. A magnetic field generating device used for a thermotherapy method comprising:

a series resonance circuit having a magnetic field generating coil and a resonance condenser, said magnetic field generating coil comprising a disc-shaped coil device comprising a current path extending in a shape of a spiral in substantially a single plan, said current path comprising a hollow cylindrical member of a nonmagnetic material inside which a space is formed and a plurality of conductive wires covered with an insulation material are arranged on a periphery of said hollow cylindrical member, wherein;

each conductive wire is arranged in a circumference of a circle in a predetermined diameter seen from a cross-sectional direction of the current path,

said conductive wires are provided with a twist along a line of a central axis of the current path,

the diameters of said conductive wires range from 0.06 mm to 0.1 mm,

the inner diameter of said hollow cylindrical member ranges from 5 mm to 40 mm,

a cooling agent is circulated inside said hollow cylindrical member,

a core plate of a high permeability material having an outer diameter equal to or larger than an outermost diameter of said disc-shaped coil is arranged on one side of the plane of said disc-shaped coil device, and

said magnetic field generating device is used for the thermotherapy method in which a magnetic flux is irradiated from outside to a patient to selectively heat a specific portion of the patient.

2. The magnetic field generating device according to claim 1, wherein said conductive wires are arranged onefoldly or twofoldly along the periphery of the hollow cylindrical member.

3. The magnetic field generating device according to claim 1, wherein the number of the conductive wires arranged on the periphery of said hollow cylindrical member ranges from 1,000 to 100,000.

4. The magnetic field generating device according to claim 1, wherein said disc-shaped coil device and said core plate are arranged inside a case of a nonmagnetic material in which a cooling agent is circulated to cool off the coil device and the core plate.

5. The magnetic field generating device according to claim 1, wherein said conductive wires are arranged twofoldly along the periphery of the hollow cylindrical member.