Open bore field free line magnetic particle imaging system

A magnetic particle imaging system, comprising:

• a computer control (20);
• a first selection field transmit unit (21) and a second selection field transmit unit (22), the first selection field transmit unit (21) and a second selection field transmit unit (22) adapted to generate and rotate a Field Free Line (FFL) at a desired z-axis position on a plane perpendicular to a z-axis (5),
• wherein each of the first selection field transmit unit (21) and a second selection field transmit unit (22) includes a plurality of power supplies each associated with transmit circuitry, the plurality of power supplies and associated transmit circuitries comprising at least a first power supply (23a) associated with a first transmit circuitry (24a), a second power supply (23b) associated with a second transmit circuitry (24b), a third power supply (23c) associated with a third transmit circuitry (24c), and a fourth power supply (23d) associated with a fourth transmit circuitry (24d),
• a first selection field coil group (1), the first selection field coil group (1) comprising a first selection field coil (1a), a second selection field coil (1b), a third selection field coil (1c), and a fourth selection field coil (1d), the first selection field coil (1a), the second selection field coil (1b), the third selection field coil (1c), and the fourth selection field coil (1d) being fed with respective first current (I1a), second current (I1b), third current (I1c), and fourth current (I1d);
• and
• a second selection field coil group (2), the second selection field coil group (2) comprising a first selection field coil (2a), a second selection field coil (2b), a third selection field coil (2c), and a fourth selection field coil (2d), the first selection field coil (2a), the second selection field coil (2b), the third selection field coil (2c), and the fourth selection field coil (2d) being fed with respective first current (I2a), second current (I2b), third current (I2c), and fourth current (I2d),
• wherein the computer control (20) is adapted to control and monitor currents applied to the selection field coils (1a, 1b, 1c, 1d, 2a, 2b, 2c, 2d),
• wherein the first selection field coil (1a) of the first selection field coil group (1) and the third selection field coil (1c) of the first coil group (1) are upper selection field coils, and the second selection field coil (1b) of the first coil group (1) and the fourth selection field coil (1d) of the first coil group (1) are lower selection field coils,
• wherein the second selection field coil (2a) of the second selection field coil group (2) and the third selection field coil (2c) of the second coil group (2) are upper selection field coils, and the second selection field coil (2b) of the second coil group (2) and the fourth selection field coil (2d) of the second coil group (2) are lower selection field coils, and
• wherein the magnitudes of the currents in the upper selection field coils (1a, 1c) of the first selection field coil group (1) are equal, while their signs are opposite, and the magnitudes of the currents in the lower selection field coils (1b, 1d) of the first selection coil group (1) are equal, while their signs are opposite (I1a=−I1c, I1b=−I1d, I2a=−I2c, I2b=−I2d).

An open bore coil system for magnetic particle imaging, enabling electronic steering and rotation of a Field Free Line (FFL) and exciting magnetic particles inside a volume, comprising:

• a first coil group with two layers of sectoral coil arrays two layers of coils, wherein each layer comprising a plural number of sectoral coils, wherein each sectoral coil has at least two edges adjacent to one edge of each of the two adjacent coils, and the current directions and amplitudes of the coils are arranged such that the magnetic field vanishes inside a desired tubular volume on a planar or-non planar surface between the layers of the sectoral coil arrays;
• a second coil group, generating homogeneous oscillating magnetic field in one or more directions inside a volume to excite magnetizable particles and translate the field free line inside the imaging volume;
• and
• a third coil group generating homogeneous magnetic field inside a volume to steer the field free line to extend the field of view of the imaging volume.