Patent ID: 9044160
Filing Date: 2015-06-02
Classification: A61B,G01R

Abstract:
1. An apparatus for generating and changing a magnetic field in a field of view ( 28 ), said magnetic field having a ball-shaped or line-shaped, first sub-zone ( 62 ) having a low magnetic field strength and a second sub-zone ( 64 ) having a higher magnetic field strength, which apparatus comprises: at least three pairs of first coils ( at least one pair of second coils ( generator means ( control means ( i) selection field current signals for provision to said first coils ( 136 a - 136 d ) so that the at least three pairs of first coils generate a gradient magnetic selection field having a pattern in space of its magnetic field strength such that the ball-shaped or line-shaped, first sub-zone having a low magnetic field strength and the second sub-zone having a higher magnetic field strength are formed in the field of view and ii) drive field current signals for provision to said second coils ( 116 ) and to two pairs ( 136 a , 136 c ) of first coils so that the at least one pair of second coils and said two pairs of first coils generate a homogeneous magnetic drive field for changing the position in space of the first and second sub-zones in the field of view.