COIL ARRANGEMENT FOR MPI

• US 20140320132A1
• Filed: 11/28/2012
• Published: 10/30/2014
• Est. Priority Date: 12/02/2011
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Schmale, Ingo
• Granted Patent: US 9,759,789 B2
• Time in Patent Office: Days
• US Class Current: 324/322
• CPC Class Codes: A61B 5/0515 Magnetic particle imaging
• CPC Class Codes: G01R 33/385 using gradient magnetic field coils
• 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

The present invention relates to a coil arrangement, in particular for use in a magnetic particle imaging apparatus (100), comprising a coil split into at least two coil segments, wherein the winding direction is inverted between at least one coil segment to another coil segment, and a capacitor coupled between at least two adjacent coil segments. Further, the present invention relates to such a magnetic particle imaging apparatus, in particular an apparatus (100) for influencing and/or detecting magnetic particles in a field of view (28), which apparatus comprises selection means and drive means (120) wherein at least one drive field coil and/or at least one selection field coil representing a selection field element is implemented by a coil arrangement as proposed according to the present invention.

Claims

1. A coil arrangement, in particular for use in a magnetic particle imaging apparatus (100), comprising:

a coil split into at least two coil segments each comprising a plurality of windings and each having a start point and an end point, wherein the winding direction is inverted between neighboring coil segments so that either the start points or the end points of two neighboring coil segments are adjacent to each other, and

a capacitor directly coupled between an end point of a coil segment and a start point of a neighboring coil segment.

2. The coil arrangement as claimed in claim 1,

wherein the winding direction is inverted from coil segment to coil segment.

3. The coil arrangement as claimed in claim 1,

wherein the coil is split into 2 to 10, in particular into 2 to 5, segments.

4. The coil arrangement as claimed in claim 1,

wherein the coil is split into an odd number of coil segments.

5. The coil arrangement as claimed in claim 1,

wherein the coil is a solenoid coil or a saddle coil.

6. The coil arrangement as claimed in claim 1,

wherein the coil segments are made of Litz wire.

7. The coil arrangement as claimed in claim 1,

wherein at least two coil segments comprise a winding of a different winding type, in particular using different wire diameters, different strand wire diameters filling factors, number of wires or strands in parallel, types of conductors, types of insulators and/or types of wires.

8. The coil arrangement as claimed in claim 1,

wherein at least one coil segment uses a winding made from two Litz wires wound in parallel.

9. An apparatus (100) for influencing and/or detecting magnetic particles in a field of view (28), which apparatus comprises:

selection means comprising a selection field signal generator unit (110) and selection field elements (116) for generating a magnetic selection field (50) having a pattern in space of its magnetic field strength such that a first sub-zone (52) having a low magnetic field strength where the magnetization of the magnetic particles is not saturated and a second sub-zone (54) having a higher magnetic field strength where the magnetization of the magnetic particles is saturated are formed in the field of view (28),

drive means (120) comprising a drive field signal generator unit (122) and drive field coils (124;

125, 126, 127) for changing the position in space of the two sub-zones (52, 54) in the field of view (28) by means of a magnetic drive field so that the magnetization of the magnetic material changes locally,

wherein at least one drive field coil and/or at least one selection field coil representing a selection field element is implemented by a coil arrangement as claimed in claim 1.

10. The apparatus (100) as claimed in claim 9 comprising

selection-and-focus means (120) including said selection means for generating a magnetic selection-and-focus field (50) having a pattern in space of its magnetic field strength such that the first sub-zone (52) and the second sub-zone (54) are formed in the field of view (28) and for changing the position in space of the field of view (28) within an examination area (230), said selection-and-focus means comprising at least one set of selection-and-focus field coils (114;

113, 115-119) and a selection-and-focus field generator unit (112) for generating selection-and-focus field currents to be provided to said at least one set of selection-and-focus field coils (114;

113, 115-119) for controlling the generation of said magnetic selection-and-focus field,

wherein said at least one set of selection-and-focus field coils comprises

at least one inner selection-and-focus field coil (113, 115) being formed as a closed loop about an inner coil axis (115a), first inner selection-and-focus field coil (115) and

a group of at least two outer selection-and-focus field coils (116-119) arranged at a larger distance from said inner coil axis (115a) than said at least one inner selection-and-focus field coil (113, 115) and at different angular positions, each being formed as a closed loop about an associated outer coil axis (116a-119a).

11. The apparatus (100) as claimed in claim 10, at least one selection-and-focus field coil.

12. An apparatus (100) as claimed in claim 10,

wherein said selection-and-focus means further comprises at least one pole shoe (310, 320;

510, 520) having a number of pole shoe segments (311-316) carrying the various selection-and-focus field coils and a pole shoe yoke (317) connecting said pole shoe segments (311-316).

13. An apparatus (100) as claimed in claim 10,

wherein said selection-and-focus means comprises

i1) a first set of selection-and-focus field coils (113, 115-119),

i2) at least one second set of selection-and-focus field coils (133, 135, 136), and

i3) a selection-and-focus field generator unit (112) for generating selection-and-focus field currents to be provided to said first and said sets of selection-and-focus field coils for controlling the generation of said magnetic selection-and-focus field.

14. An apparatus (100) as claimed in claim 10,

wherein said drive field coils (125-127) are arranged in the area between said first inner selection-and-focus field coils of the two sets of selection-and-focus field coils.

15. An apparatus (100) as claimed in claim 10,

wherein said drive field coils comprises two pairs of saddle coils (125, 126) arranged around a central symmetry axis (250) perpendicular to said inner coil axis (115a) and a solenoid coil (127) arranged around said central symmetry axis (250).