Method and System for Determining an Orientation and an X-Coordinate of a Movable Object Relative to a B0 Field Magnet

A system for determining an orientation of a movable object relative to a B0 field magnet of a magnetic resonance tomography device in an xz-coordinate plane by a three-dimensional magnetic field strength sensor arranged at a fixed relative position on the object, the system comprising:

• a first interface configured to receive B0 reference data of the B0 field magnet with characteristic magnetic field strengths for a number of xyz-coordinates;
• a second interface configured to receive first measurement values of the magnetic field strength sensor at a first position, the first measurement values including at least field strength components of the B0 field;
• a third interface configured to receive second measurement values of the magnetic field strength sensor at a second position, the second measurement values including at least field strength components of the B0 field;
• and
• a controller in communication with the first, the second, and the third interfaces and configured to:
• position the object at a first position outside the B0 field magnet with regard to a z-coordinate axis;
• determine a first angle value based on the first measurement values of the magnetic field strength sensor at the first position and the B0 reference data;
• position the object at a second position within the B0 field magnet with regard to the z-coordinate axis;
• determine a second angle value based on the second measurement values of the magnetic field strength sensor at the second position and the B0 reference data;
• correct the first angle value based on the second angle value to determine a corrected first angle value;
• and
• provide the corrected first angle value in electronic form as a data file.

An apparatus comprising:

• one or more processors;
• and
• memory storing instructions that, when executed by the one or more processors, cause the apparatus to:
• position a movable object at a first position, with respect to a z-coordinate axis, outside a B0 field magnet of a magnetic resonance tomography device;
• obtain first measurement values of a three-dimensional magnetic field strength sensor at the first position, the first measurement values including at least field strength components of a B0 field;
• determine a first angle value based on the first measurement values of the magnetic field strength sensor at the first position and B0 reference data of the B0 field magnet with characteristic magnetic field strengths for a number of xyz-coordinates;
• position the object at a second position within the B0 field magnet with respect to the z-coordinate axis;
• obtain second measurement values of the magnetic field strength sensor at the second position, the second measurement values including at least field strength components of the B0 field;
• determine a second angle value based on the second measurement values of the magnetic field strength sensor at the second position and the B0 reference data;
• correct the first angle value based on the second angle value to determine a corrected first angle value;
• and
• determine an orientation of the movable object relative to the B0 field magnet based on the corrected first angle value.