MRI Table Orientation Tracking via B0 Field Sensor Triangulation

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Solution Overview

Problem

The process of manually moving a patient table towards a B0 field magnet in an MRI scanner is prone to inaccuracies due to vibrations, necessitating a method to simplify and stabilize the orientation and positioning of movable objects relative to the B0 field magnet.

Innovation Solution

A method using three-dimensional magnetic field strength sensors arranged on the object to determine position and orientation data, independent of the object's orientation, which are then filtered based on known sensor positions to provide accurate orientation and position values for automatic navigation and docking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual moving of patient table is used, then ease of operation is improved, but positioning precision deteriorates due to vibrations

Engineering Contradiction:
Improvemanual operationVSAvoidpositioning precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces the manual mechanical positioning system with an automated navigation system that uses magnetic field sensors to detect position and orientation relative to the B0 field magnet. The system automatically calculates navigation data and controls the patient table movement, eliminating manual operation vibrations while achieving precise positioning through electronic control and feedback mechanisms.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If automated gripping device is used to correct positioning inaccuracies, then positioning precision is improved, but device complexity increases

Engineering Contradiction:
Improvepositioning accuracyVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements preliminary action by pre-defining the target position and orientation of the patient table relative to the B0 field magnet before movement begins. The navigation system calculates the optimal path and required corrections in advance, allowing the automated gripping device to make precise, pre-planned adjustments rather than reactive corrections, thereby reducing the complexity of real-time control mechanisms.

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If magnetic field strength sensors are used to determine position independent of orientation, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveposition measurement accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses the magnetic field itself as an intermediary reference system. Magnetic field strength sensors detect the characteristic magnetic field strengths of the B0 field magnet, and the system calculates position data based on these field measurements. This intermediary magnetic field reference allows the system to determine position independently of the patient table's orientation, achieving high measurement precision without requiring complex mechanical alignment systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables precise, automated, and efficient alignment of the patient table with the B0 field magnet, enhancing patient comfort and reducing manual intervention.

Implementation Method 1

providing BO reference data of the B0 field magnet with characteristic magnetic field strengths for a variety of XYZ coordinates; determining position data for each magnetic field strength sensor by evaluating measured component values of the respective magnetic field strength sensor

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP4650805A1Method and system for determining an orientation and a position of a moving object relative to a b0 field magnet
Publication Date: 2025.11.19 SIEMENS HEALTHINEERS AG
  • EP4650805A1 patent drawingFigure 1
  • EP4650805A1 patent drawingFigure 2~3
  • EP4650805A1 patent drawingFigure 4

AI summary

Method for determining the orientation and position of a moving object (120) relative to a B0 field magnet (110) of a magnetic resonance imaging scanner (100) in an XZ coordinate plane in an XYZ coordinate system aligned with the B0 field magnet (110), the method comprising at least the following steps: providing (40) B0 reference data of the B0 field magnet (110) with characteristic magnetic field strengths for a plurality of XYZ coordinates; providing (41) at least three three-dimensional magnetic field strength sensors (145, 146, 147) arranged in a fixed relative position on the object (120); Determining (42) position data for a respective magnetic field strength sensor (145, 146, 147) by evaluating measured component data of the respective magnetic field strength sensor (145, 146, 147) that are independent of the respective orientation of the moving object (120) in the XZ coordinate plane;Filtering (43) the determined position data of the magnetic field strength sensors (145, 146, 147) based on the fixed relative position of the magnetic field strength sensors (145, 146, 147) and providing filtered position data; providing (44) an orientation value and a position of the moving object (120) relative to the B0 field magnet (110) based on the filtered position data.;