Method and Device for Position Determination in a Magnetic Resonance Tomography Unit

A shim coil comprising:

• a magnetic field strength sensor and an orientation sensor that are arranged on the shim coil,
• wherein the magnetic field strength sensor is configured to record an amount and a direction of a magnetic field vector;
• and
• wherein the orientation sensor is configured to record a relative alignment of the orientation sensor to a predetermined spatial direction.

A magnetic resonance tomography unit comprising:

• a B0 field magnet;
• a device;
• a mobile patient couch;
• a controller;
• and
• a storage unit,
• wherein a magnetic field strength sensor is arranged on the device that is in signal connection with the controller,
• wherein the patient couch is configured, parallel to a z-coordinate axis that is defined by a symmetry axis of the B0 field magnet in a preferred direction of a B0 field, to be moved into a scanning area of the B0 field magnet by the controller,
• wherein a characteristic magnetic field strength Bref of the B0 field magnet in a range of between 20% and 80% of magnetic field strength of the B0 field magnet at an isocenter is stored in the storage unit, and
• wherein the controller is configured to determine a reference z-coordinate zref by moving the patient couch with the device parallel to the z-coordinate axis relative to the B0 field magnet and magnetic field strength values being recorded by the magnetic field strength sensor via a signal line and compared with the characteristic magnetic field strength Bref until a difference between the recorded magnetic field strength values and the characteristic magnetic field strength Bref is smaller than a predetermined tolerance value.