Electromagnet gradient coil apparatus for micro-device localization

Patent metadata

Field	Value
Publication number	US-11457835-B2
Application number	US-202017097349-A
Country	US
Kind code	B2
Filing date	Nov 13, 2020
Priority date	Nov 13, 2019
Publication date	Oct 4, 2022
Grant date	Oct 4, 2022

Abstract

An apparatus for producing magnetic field gradients includes (a) a first planar electromagnet coil set configured to produce a first magnetic field gradient with respect to a first axis, (b) a second planar electromagnet coil set configured to produce a second magnetic field gradient with respect to a second axis that is orthogonal to the first axis, (c) a third planar electromagnet coil set configured to produce a third magnetic field gradient with respect to a third axis that is orthogonal to the first and second axes, and (d) a controller configured to selectively provide power to the first, second, and/or third electromagnet coil sets to sequentially produce a localization magnetic field gradient with respect to each of the first, second, and third axes, at least a portion of each localization magnetic field gradient having a monotonically-varying magnetic field magnitude along a respective axis.

First claim

What is claimed is:

1. An apparatus for producing magnetic field gradients comprising:
a first planar electromagnet coil set configured to produce a first magnetic field gradient with respect to a first axis;
a second planar electromagnet coil set configured to produce a second magnetic field gradient with respect to a second axis that is orthogonal to the first axis;
a third planar electromagnet coil set configured to produce a third magnetic field gradient with respect to a third axis that is orthogonal to the first and second axes, the first, second, and third planar electromagnet coil sets vertically arranged with respect to the third axis; and
a controller configured to selectively provide power to the first planar electromagnet coil set, the second planar electromagnet coil set, and/or the third planar electromagnet coil set to sequentially produce a localization magnetic field gradient with respect to each of the first, second, and third axes, at least a portion of each localization magnetic field gradient having a monotonically-varying magnetic field magnitude along a respective axis,
wherein the controller is configured to provide power simultaneously to only the first and third planar electromagnet coil sets to thereby produce a first localization magnetic field gradient with respect to the first axis.

2. The apparatus of claim 1 , wherein the first planar electromagnet coil set, the second planar electromagnet coil set, and the third planar electromagnet coil set are stacked.

3. The apparatus of claim 1 , wherein the first planar electromagnet coil set includes a clockwise spiral winding and a counterclockwise spiral winding that are disposed adjacent to each other.

4. The apparatus of claim 3 , wherein the clockwise spiral winding and the counterclockwise spiral winding are each formed by a respective wire.

5. The apparatus of claim 3 , wherein:
the clockwise spiral winding and the counterclockwise spiral winding are each elongated in a direction parallel to the second axis,
the clockwise spiral winding and the counterclockwise spiral winding each have an axis of symmetry that is parallel to the first axis, and
the axis of symmetry of the clockwise spiral winding is aligned with the axis of symmetry of the counterclockwise spiral winding.

6. The apparatus of claim 5 , wherein:
the first planar electromagnet coil set has a width that is parallel to the first axis, and
a ratio of (a) the at least a portion of the localization magnetic field gradient that has the monotonically-varying magnetic field magnitude along the first axis to (b) the width of the first planar electromagnet coil set is within a range of about 1:2 to about 3:4.

7. The apparatus of claim 6 , wherein the ratio is about 2:3.

8. The apparatus of claim 3 , wherein:
the clockwise spiral winding is a first clockwise spiral winding,
the counterclockwise spiral winding is a first counterclockwise spiral winding, and
the second planar electromagnet coil set includes a second clockwise spiral winding and a second counterclockwise spiral winding that are disposed adjacent to each other.

9. The apparatus of claim 8 wherein the first clockwise spiral winding, the second clockwise spiral winding, the first counterclockwise spiral winding, and the second counterclockwise spiral winding are each formed by a respective wire.

10. The apparatus of claim 8 , wherein:
the first clockwise spiral winding and the first counterclockwise spiral winding are each elongated in a direction parallel to the second axis,
the first clockwise spiral winding and the first counterclockwise spiral winding each have an axis of symmetry that is parallel to the first axis,
the axis of symmetry of the first clockwise spiral winding is aligned with the axis of symmetry of the first counterclockwise spiral winding,
the second clockwise spiral winding and the second counterclockwise spiral winding are each elongated in a direction parallel to the first axis,
the second clockwise spiral winding and the second counterclockwise spiral winding each have an axis of symmetry that is parallel to the second axis, and
the axis of symmetry of the second clockwise spiral winding is aligned with the axis of symmetry of the second counterclockwise spiral winding.

11. The apparatus of claim 10 , wherein:
the first planar electromagnet coil set has a width that is parallel to the first axis,
the second planar electromagnet coil set has a length that is parallel to the second axis,
a ratio of (a) the at least a portion of the localization magnetic field gradient that has the monotonically-varying magnetic field magnitude along the first axis to (b) the width of the first planar electromagnet coil set is greater than or equal to about 1:2, and
a ratio of (c) the at least a portion of the localization magnetic field gradient that has the monotonically-varying magnetic field magnitude along the second axis to (d) the length of the second planar electromagnet coil set is less than or equal to about 1:2.

12. The apparatus of claim 11 , wherein:
the ratio (a) the at least a portion of the localization magnetic field gradient that has the monotonically-varying magnetic field magnitude along the first axis to (b) the width of the first planar electromagnet coil set is within a range of about 1:2 to about 3:4, and
the ratio of (c) the at least a portion of the localization magnetic field gradient that has the monotonically-varying magnetic field magnitude along the second axis to (d) the length of the second planar electromagnet coil set is within a range of about 1:2 to about 3:4.

13. The apparatus of claim 11 , wherein the third planar electromagnet coil set includes a spiral winding having a form of an annulus.

14. The apparatus of claim 13 , wherein:
the annulus has an outer diameter measured parallel to the first axis, and
a ratio of (e) the at least a portion of the localization magnetic field gradient that has the monotonically-varying magnetic field magnitude along the third axis to (f) the outer diameter of the annulus is within a range of about 1:4 to about 2:5.

15. The apparatus of claim 14 , wherein the ratio of (e) the at least a portion of the localization magnetic field gradient that has the monotonically-varying magnetic field magnitude along the third axis to (f) the outer diameter of the annulus is about 1:3.

16. The apparatus of claim 1 , wherein the first localization magnetic field gradient comprises a total magnetic field produced by the first and third planar electromagnet coil sets.

17. The apparatus of claim 16 , wherein the controller is configured to provide power simultaneously to only the second and third planar electromagnet coil sets to thereby produce a second localization magnetic field gradient with respect to the second axis.

18. The apparatus of claim 16 , wherein the second localization magnetic field gradient comprises a total magnetic field produced by the second and third planar electromagnet coil sets.

19. The apparatus of claim 17 , wherein the controller is configured to provide power to only the third planar electromagnet coil set to thereby produce a third localization magnetic field gradient with respect to the third axis.

20. The apparatus of claim 17 , wherein the controller is configured to selectively provide the power according to a predetermined time sequence to encode each localization magnetic field gradient.

21. A method for manufacturing comprising:
forming a first planar electromagnet coil set

Assignees

• California Inst Of Techn

Inventors

• Sharma Saransh
• Shapiro Mikhail
• Emami Azita

Classifications

• A61B5/05 Primary

  Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves (measuring movement of the entire body or parts thereof A61B5/11; detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof A61B5/24) · CPC title

• G01B7/31

  for testing the alignment of axes · CPC title

• G01R33/385

  using gradient magnetic field coils · CPC title

• A61B5/076

  Permanent implantation · CPC title

• A61B5/6861

  Capsules, e.g. for swallowing or implanting · CPC title