Coil for magnetic induction to tomography imaging

• US 9,207,197 B2
• Filed: 02/27/2014
• Issued: 12/08/2015
• Est. Priority Date: 02/27/2014
• Status: Active Grant

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Feldkamp, Joseph R.
• Primary Examiner(s): Arana, Louis
• Application Number:
  US14/191,941
• Publication Number:
  US 20150241373A1
• Time in Patent Office: 649 Days
• Field of Search: 324/228, 324/243, 324/240, 333/131, 333/124
• US Class Current: 1/1
• CPC Class Codes: A61B 5/0522 Magnetic induction tomography
• CPC Class Codes: A61B 5/4566 Evaluating the spine A61B5/4561 takes precedence
• CPC Class Codes: G01N 27/023 where the material is placed in the field of a coil
• CPC Class Codes: H01F 27/2823 Wires H01F27/2866 takes precedence
• CPC Class Codes: H01F 27/2871 Pancake coils
• CPC Class Codes: H01F 27/303 Clamping coils, windings or parts thereof together
• CPC Class Codes: H01F 7/20 without armatures cores H01F3/00; coils H01F5/00 ; shaping metal by applying magnetic forces B21D26/14; electromagnets specially adapted for NMR applications G01R33/381

Abstract

A coil for facilitating magnetic induction tomography imaging of a specimen, such as a human tissue specimen, using a single coil is provided. The coil can include a plurality of concentric conductive circular loops. The concentric conductive loops can be connected in series with connection traces without allowing the connection traces to distort the fields produced by the plurality of concentric conductive circular loops. The plurality of concentric conductive loops can be arranged in multiple planes (e.g. on a multilayer printed circuit board) as a two layer stack. The spacing between the planes or the plane separation distance can be selected such that mathematically the plurality of conductive loops can be treated as being located in a common plane for purposes of a quantitative analytical model used for magnetic induction tomography imaging.

Claims

1. A coil for magnetic induction tomography imaging of a specimen, comprising:

a plurality of first concentric conductive loops located within a first plane, the plurality of first concentric conductive loops connected in series; and

a plurality of second concentric conductive loops located within a second plane, the second plane spaced apart from the first plane by a plane separation distance, the plurality of second concentric conductive loops connected in series;

wherein the plurality of first concentric conductive loops are connected in series with the plurality of second concentric conductive loops, the plurality of first concentric conductive loops and the plurality of second concentric conductive loops being disposed such that each of the plurality of first concentric conductive loops overlaps one of the plurality of second concentric conductive loops.

2. The coil of claim 1, wherein the plane separation distance is selected such that the plurality of first concentric conductive loops and the plurality of second concentric conductive loops approximate a single plane of concentric conductive loops in a model used for magnetic induction tomography imaging.

3. The coil of claim 1, wherein the plane separation distance is in the range of 0.2 mm to 0.7 mm.

4. The coil of claim 1, wherein the plurality of first concentric conductive loops and the plurality of second concentric conductive loops are connected in series using a plurality of connection traces.

5. The coil of claim 4, wherein the plurality of connection traces are arranged such that fields emanating from the connection traces oppose each other.

6. The coil of claim 4, wherein the plurality of connection traces are radially aligned to connect the plurality of first concentric conductive loops and the plurality of second concentric conductive loops in series such that a current flow of one of the plurality of connection traces located in the first plane is opposite a current flow of one of the plurality of connection traces located in the second plane.

7. The coil of claim 1, wherein each of the plurality of first concentric conductive loops has a gap to facilitate series connection of the plurality of first concentric conductive loops.

8. The coil of claim 7, wherein each of the plurality of second concentric conductive loops has a gap to facilitate series connection of the plurality of second concentric conductive loops.

9. The coil of claim 8, wherein the gap associated with one of the plurality of first concentric conductive loops is offset from the gap associated with one of the plurality of second concentric conductive loops.

10. The coil of claim 1, wherein a first innermost conductive loop of the plurality of first concentric conductive loops is coupled to an RF energy source and a second innermost conductive loop of the plurality of second concentric conductive loops is coupled to a reference node.

11. The coil of claim 1, wherein the coil is coupled to a measurement circuit capable of determining a change in impedance of the coil.

21. The coil of claim 1, wherein the specimen comprises a tissue specimen.

22. The coil of claim 21, wherein the tissue specimen comprises a human tissue specimen.

12. A method for providing a coil for magnetic induction tomography imaging, the method comprising:

arranging a plurality of first concentric conductive loops in a first plane on a multilayer printed circuit board;

arranging a plurality of second concentric conductive loops in a second plane on the multilayer printed circuit board;

coupling the plurality of first concentric conductive loops in series using a plurality of first connection traces; and

coupling the plurality of second concentric conductive loops in series using a plurality of second connection traces;

wherein the plurality of first connection traces and the plurality of second connection traces are radially aligned to connect the plurality of first concentric conductive loops and the plurality of second concentric conductive loops in series such that a current flow of one of the plurality of first connection traces is opposite a current flow of one of the plurality of second connection traces.

13. The method of claim 12, wherein the first plane and the second plane are separated by a plane separation distance.

14. The method of claim 13, wherein the plane separation distance is selected such that the plurality of first concentric conductive loops and the plurality of second concentric conductive loops approximate a single plane of concentric conductive loops in a model used for magnetic induction tomography imaging.

15. The method of claim 14, wherein the plane separation distance is selected to be in the range of about 0.2 mm to about 0.7 mm.

16. The method of claim 12, wherein the method comprises coupling a first innermost conductive loop of the plurality of first concentric conductive loops to an RF energy source and coupling a second innermost conductive loop of the plurality of second concentric conductive loops to a reference node.

17. A system for magnetic induction tomography imaging, comprising:

an RF energy source;

a coil coupled to the RF energy source, the coil comprising a plurality of first concentric conductive loops located within a first plane, the plurality of first concentric conductive loops connected in series with one another;

the coil further comprising a plurality of second concentric conductive loops located within a second plane, the plurality of second concentric conductive loops connected in series with one another; and

a measurement circuit capable of obtaining a measurement of an electrical parameter of the coil when the coil is placed adjacent to a specimen;

wherein the first plane and the second plane are separated by a plane separation distance, the plane separation distance selected such that the plurality of first concentric conductive loops and the plurality of second concentric conductive loops approximate a single plane of concentric conductive loops in a model used for magnetic induction tomography imaging.

18. The system of claim 17, wherein the measurement circuit comprises:

a phase measurement circuit configured to measure a phase angle between a current and a voltage associated with the coil; and

a voltage gain measurement circuit configured to measure a voltage gain based at least in part on the voltage associated with the coil and a voltage across a sense resistor coupled in series with the coil.

19. The system of claim 17, wherein the RF energy source is coupled to an innermost conductive loop of the plurality of first concentric conductive loops.

20. The system of claim 18, wherein the coil comprises a plurality of radially aligned connection traces connecting the plurality of first concentric conductive loops and the plurality of second concentric conductive loops in series such that a current flow of one of the plurality of connection traces located in the first plane is opposite a current flow of one of the plurality of connection traces located in the second plane.