MRI Magnet Field Control for MR-Incompatible Object Detection
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face operational hazards due to the attraction and potential collision of MR-incompatible objects, such as ferromagnetic materials, with the strong magnetic field, which can cause damage to the magnet or harm to patients during scanning.
Innovation Solution
The implementation of a sensor-based detection system that determines the location of MR-incompatible objects relative to the MRI system, using devices like cameras, Gauss meters, or magnetic field probes, to assess operational hazards and automatically reduce or shut down the polarizing magnetic field to prevent accidents, and subsequently ramp up the field when the hazard is mitigated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the polarizing magnetic field strength is increased to improve imaging quality, then the imaging capability is improved, but the risk of attracting MR-incompatible objects increases
Solution Approach 1:
The system performs preliminary detection of MR-incompatible objects using sensor devices (cameras, Gauss meters, magnetic field probes) before initiating or continuing MRI scanning. This allows the system to identify hazards in advance and prevent them from causing harm, resolving the contradiction by enabling high-field operation only when safe.
Solution Approach 2:
The system continuously monitors the environment during MRI operation using sensor devices that detect the presence and movement of MR-incompatible objects. When objects are detected or move into hazardous zones, the system provides feedback to reduce or shut down the magnetic field, allowing safe operation at high field strengths when no objects are present.
2Reliability
If automatic detection and field reduction systems are implemented to improve safety, then patient and system safety is improved, but the system complexity increases
Solution Approach 1:
The safety system is divided into independent modular components: sensor devices (cameras, Gauss meters, magnetic field probes), processing units for analyzing sensor data, and control units for managing magnetic field adjustments. This segmentation allows each component to be optimized independently and simplifies maintenance while maintaining overall system reliability.
Solution Approach 2:
The patent introduces intermediate processing layers between the sensor devices and the magnetic field control system. These intermediaries process sensor data, determine whether objects pose hazards, and generate appropriate control signals, thereby managing complexity through structured information processing rather than direct complex control.
3Object-affected harmful factors
If the magnetic field is reduced to prevent hazards, then safety is improved, but the imaging capability deteriorates
Solution Approach 1:
The magnetic field strength is dynamically adjusted based on real-time detection of MR-incompatible objects. The system maintains high field strength for optimal imaging when no hazards are present, and only reduces field strength when objects are detected or move into hazardous zones. This dynamic adaptation resolves the contradiction by ensuring high imaging quality during normal operation while providing safety when needed.
Solution Approach 2:
The system changes the magnetic field parameter (strength) in response to detected conditions. By monitoring object presence and movement, the system adjusts the field strength parameter to appropriate levels, maintaining high fields for imaging quality when safe and reducing fields to prevent hazards when objects are present, thus resolving the contradiction through conditional parameter modification.
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
This solution effectively prevents damage to the MRI system and ensures patient safety by automatically reducing the magnetic field strength when hazardous objects are detected within the safety zone, allowing for safe operation and rapid recovery when the hazard is removed.
Implementation Method 1
a main magnet accommodated by said housing and configured to generate a polarizing magnet field with the bore
Implementation Method 2
The sensor device may include one of: a Gauss meter, a Hall probe, a magnetic field probe, or an optical tracker
Implementation Method 3
Detecting the location information may include detecting a change in a current that powers a main magnet of the MRI system, the change being induced by a motion of the MR-incompatible object within the polarizing magnetic field
Data Source
AI summary
Some implementations provide a method for safe operation of a magnetic resonance imaging (MRI) system, the method including: determining, at least in part by using a sensor device, location information that indicates a location of an MR-incompatible object relative to the MRI system, the MRI system generating a polarizing magnetic field for imaging a subject; based on the determined location information, determining, by a control unit associated with the MRI system, that the MR-incompatible object poses an operational hazard to the MRI system; and in response to determining that the MR-incompatible object poses an operational hazard to the MRI system, reducing, by the control unit, a strength of the polarizing magnetic field.