APPARATUS AND METHOD FOR INFLUENCING AND/OR DETECTING MAGNETIC PARTICLES IN A FIELD OF VIEW HAVING AN ARRAY OF SINGLE-SIDED TRANSMIT COIL SETS

• US 20120310076A1
• Filed: 01/28/2011
• Published: 12/06/2012
• Est. Priority Date: 02/08/2010
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Buzug, Thorsten Manuel, Sattel, Timo Frederik, Knopp, Tobias, Biederer, Sven
• Granted Patent: US 9,008,749 B2
• Time in Patent Office: Days
• US Class Current: 600/409
• CPC Class Codes: A61B 5/05 Detecting, measuring or recording for diagnosis by means of electric currents or magnetic fields; Measuring using microwaves or radio waves impedance plethysmography A61B5/0295; 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 Class Codes: A61B 5/0515 Magnetic particle imaging

Abstract

The present invention relates to an apparatus and a method for influencing and/or detecting magnetic particles in a field of view. To increase the field of view and, at the same time, allow access to the patient during imaging, the apparatus comprises two or more transmit coil sets (200) wherein neighboring coil sets are partially overlapping, a transmit coil set comprising: a pair (210) of concentrically arranged selection field coils (211, 212) 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 and a second sub-zone (54) having a higher magnetic field strength are formed in the field of view (28), and at least one pair (220, 230) of drive field coils (221, 222; 231, 232) 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 particles changes locally, said at least one pair (220, 230) of drive field coils being arranged parallel to said pair (210) of selection field coils (211, 212) and being formed by two neighboring coil loops.

Claims

1. An apparatus for influencing and/or detecting magnetic particles in a field of view, which apparatus comprises:

i) two or more transmit coil sets, wherein neighboring coil sets are partially overlapping, a transmit coil set comprising;

a pair of concentrically arranged selection field coils for generating a magnetic selection field having a pattern in space of its magnetic field strength such that a first sub-zone having a low magnetic field strength and a second sub-zone having a higher magnetic field strength are formed in the field of view, and

at least one pair of drive field coils for changing the position in space of the two sub-zones in the field of view by means of a magnetic drive field so that the magnetization of the magnetic particles changes locally, said at least one pair of drive field coils being arranged parallel to said pair of selection field coils and being formed by two neighboring coil loops,

ii) generator means for generating current signals for provision to said selection field coils and said drive field coils for generating the desired magnetic fields by said coils, and

iii) control means for controlling said generator means to generate direct currents of opposite directions for provision to the two selection field coils of said pair of selection field coils and alternate currents of opposite directions for provision to the two drive field coils of said at least one pair of drive field coils.

2. An apparatus as claimed in claim 1,

comprising two pairs of drive field coils, said two pairs of drive field coils being arranged parallel to each other and to said pair of selection field coils and being rotated with respect to each other by a rotation angle (α

) in the range between 0° and

180°

.

3. An apparatus as claimed in claim 2,

wherein the two pairs of drive field coils are rotated with respect to each other by a rotation angle (α

) in the range between 75° and

105°

, in particular by a rotation angle of 90°

.

4. An apparatus as claimed in claim 2,

wherein said control means is adapted for controlling said generator means to generate alternate currents of opposite directions for provision to the two selection field coils of said pair of selection field coils in addition to the direct currents of opposite directions.

5. An apparatus as claimed in claim 1,

wherein the at least one pair of drive field coils is formed by identical coil loops.

6. An apparatus as claimed in claim 1,

wherein a pair of drive field coils is formed by two, particularly identical, neighboring D-shaped or rectangular-shaped coil loops, wherein two linear branches of said loops are directly neighboring each other.

7. An apparatus as claimed in claim 1,

wherein the two coil loops of a pair of drive field coils are arranged symmetrical to a symmetry plane going through a coil axis to which said selection field coils are arranged concentric.

8. An apparatus as claimed in claim 1,

wherein the pair of selection field coils and the at least one pair of drive field coils of a transmit coil set have substantially identical outer dimensions and are disk-like arranged above each other.

9. An apparatus as claimed in claim 1,

further comprising

iv) receiving means comprising at least one receiving coil for acquiring detection signals, which detection signals depend on the magnetization in the field of view, which magnetization is influenced by the change in the position in space of the first and second sub-zone, and

v) processing means for processing said detection signals, in particular for reconstructing an image from said detection signals and/or for localizing said magnetic particles within the field of view, in particular within an object placed within the field of view.

10. An apparatus as claimed in claim 1,

comprising a plurality of transmit coil sets, which are equidistantly spaced and substantially arranged within one or more flat or curved planes.

11. An apparatus as claimed in claim 1,

wherein the control means is adapted for controlling said generator means to generate currents for provision to the coils of the transmit coil sets such that for transfer of the first sub-zone from a first transmit coil set to a second transmit coil set the first sub-zone is driven to the border of the field of view of the first transmit coil set, the magnetic selection field of the first transmit coil set is decreased and the magnetic selection field of the second transmit coil set is increased.

12. An apparatus as claimed in claim 1,

wherein the control means is adapted for controlling said generator means to generate currents for provision to the coils of the transmit coil sets such that two or more first sub-zones are generated and simultaneously moved.

14. Computer program comprising program code means for causing a computer to control an apparatus as claimed in claim 1.

15. A transmit coil set for use in an apparatus for influencing and/or detecting magnetic particles in a field of view as claimed in claim 1, which transmit coil set comprises

a pair of concentrically arranged selection field coils for generating a magnetic selection field having a pattern in space of its magnetic field strength such that a first sub-zone having a low magnetic field strength and a second sub-zone having a higher magnetic field strength are formed in the field of view, and

at least one pair of drive field coils for changing the position in space of the two sub-zones in the field of view by means of a magnetic drive field so that the magnetization of the magnetic particles changes locally, said at least one pair of drive field coils being arranged parallel to said pair of selection field coils and being formed by two neighboring coil loops.

13. An method for influencing and/or detecting magnetic particles in a field of view, which method comprises the steps of:

i) generating magnetic fields by two or more transmit coil sets, wherein neighboring coil sets are partially overlapping, said step of generating magnetic fields comprising;

generating a magnetic selection field having a pattern in space of its magnetic field strength such that a first sub-zone having a low magnetic field strength and a second sub-zone having a higher magnetic field strength are formed in the field of view by a pair of concentrically arranged selection field coils and

changing the position in space of the two sub-zones in the field of view by means of a magnetic drive field so that the magnetization of the magnetic particles changes locally by at least one pair of drive field coils, said at least one pair of drive field coils being arranged parallel to said pair of selection field coils and being formed by two neighboring coil loops,

ii) generating current signals for provision to said selection field coils and said drive field coils for generating the desired magnetic fields by said coils, and

iii) controlling said generator means to generate direct currents of opposite directions for provision to the two selection field coils of said pair of selection field coils and alternate currents of opposite directions for provision to the two drive field coils of said at least one pair of drive field coils.