MRI Patient Bed Positioning Using Magnetic Field Sensing
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Solution Overview
Problem
Existing methods for positioning a patient within the field of view of a magnetic resonance imaging (MRI) scanner are cumbersome and lack precision, particularly in determining the longitudinal position of the patient table relative to the MRI scanner's field of view, often relying on visual markers or rough estimates that do not align with the high accuracy capabilities of modern MRI systems.
Innovation Solution
A position-determining device with a magnetic field sensor, preferably a three-dimensional Hall sensor, is used to accurately determine the marker position on the patient table or patient, which communicates with the MRI's control unit to align the patient's position with the scanner's field of view, utilizing a magnetic field map and optical markers for easy user guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If visual markers or rough estimates are used to position the patient table, then the operation is simple, but the positioning precision is insufficient
Solution Approach 1:
A magnetic field sensor serves as an intermediary device between the user and the patient table positioning system. The sensor detects the magnetic field at the marker position and communicates this information to the control unit, enabling precise positioning without requiring the user to directly measure or estimate positions. This intermediary measurement device bridges the gap between simple operation and high precision.
2Ease of operation
If laser marking devices are used to indicate position, then visual guidance is provided, but the workflow becomes cumbersome due to multiple adjustment steps
Solution Approach 1:
The system implements automatic feedback control where the magnetic field sensor continuously monitors the marker position, and the control unit automatically calculates and executes the necessary patient table adjustments. This closed-loop feedback mechanism eliminates the iterative manual adjustment process required by laser marking devices, reducing both time and operational complexity.
Solution Approach 2:
The positioning system performs self-service by automatically determining the target position and executing the positioning action without requiring continuous user intervention. Once the marker is placed, the system independently completes the positioning task, freeing the user from the cumbersome back-and-forth adjustments needed with laser marking devices.
3Ease of operation
If markings along the patient bed edge are used, then position selection is simplified, but only rough indication of position is achieved
Solution Approach 1:
The patent replaces the mechanical marking system on the patient bed edge with a magnetic field-based measurement system. Instead of relying on physical markings that provide only rough guidance, the magnetic field sensor provides precise digital measurement of the marker position, maintaining ease of operation while dramatically improving precision.
4Device complexity
If the patient table is manually adjusted to align with field of view, then no additional devices are needed, but alignment precision cannot meet high accuracy requirements
Solution Approach 1:
The magnetic field sensor acts as an intermediary measurement device that provides precise feedback on the marker position relative to the patient table and field of view. This single intermediate device enables high-precision alignment while maintaining relatively simple overall system complexity, as the sensor integrates seamlessly with the existing MRI system control.
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
The method provides a simple, accurate, and intuitive way to position the patient within the MRI scanner's field of view, enhancing workflow efficiency and alignment precision without interfering with the MRI process.
Implementation Method 1
a position-determining device with a magnetic field sensor, preferably a three-dimensional Hall sensor
Implementation Method 2
A position-determining device with a magnetic field sensor, preferably a three-dimensional Hall sensor
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a method for positioning a patient bed (8) in a patient receptacle (3) of a magnetic resonance imaging (MRI) device (1), wherein the patient receptacle (3), which is in particular cylindrical, is defined by a main magnet unit (2) with a main magnet (4) generating a main magnetic field, wherein: - a position fixing means (14, 14') comprising a magnetic field sensor (16), in particular a three-dimensional one, is positioned at a marker position on the patient bed (8) or on a patient (7) lying on the patient bed (8), - the sensor data of the magnetic field sensor (16) are evaluated by means of a control device (13) to determine the marker position in a coordinate system (10) of the MRI device (1), in which a field of view position of a field of view (5) of the MRI device (1) is also known.- by means of the control device (13) a desired target position of the field of view (5) relative to the marker position is determined from the marker position at least in a longitudinal direction of the patient bed (8) corresponding to a direction of movement of the patient bed (8) for a subsequent measurement of magnetic resonance data, and - by means of the control device (13) the patient bed (8) is controlled by the control device (13) using the marker position and the field of view position such that the desired relative target position of the field of view (5) to the marker position is set.