MRI-Guided Visual Servoing for Positioning Instruments
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Solution Overview
Problem
Medical robots face material compatibility issues in MRI environments due to strong magnetic fields, which affect the precision operation of servo motors and sensors, and existing visual servoing methods are inadequate for controlling robot movements in these conditions.
Innovation Solution
An MRI-guided visual servoing system that uses continuous data from an MRI scanner to provide feedback for controlling the movement of medical robots, determining fiduciary landmarks, and directing actuators based on image Jacobian matrices to optimize positioning within the MRI environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If medical robots use servo motors and sensors for precision operation, then positioning accuracy is improved, but material compatibility issues arise in high magnetic field environments
Solution Approach 1:
The patent removes servo motors and sensors from the robot system that are incompatible with MRI environments. Instead, it uses MRI imaging itself as the feedback mechanism, extracting the positioning function from traditional robotic sensors and replacing it with medical imaging-based visual feedback.
Solution Approach 2:
The patent replaces the mechanical feedback system (servo motors and sensors) with an imaging-based visual feedback system. MRI images are processed to provide positioning information, substituting mechanical sensing with optical/imaging sensing that is compatible with magnetic field environments.
2Ease of operation
If traditional visual servoing uses external cameras mounted on robots, then motion control is achieved, but the system complexity increases and MRI compatibility is compromised
Solution Approach 1:
The patent merges the imaging function and the visual servoing function into a single integrated system. The MRI scanner serves both as the diagnostic imaging device and as the visual feedback source for robot control, eliminating the need for separate external cameras and reducing overall system complexity.
Solution Approach 2:
The MRI scanner is given a dual function: it performs both medical imaging and visual servoing feedback. This multi-functionality eliminates the need for dedicated robotic vision systems, simplifying the overall system while maintaining motion control capabilities.
3Measurement precision
If MRI data is used continuously for visual feedback, then positioning precision is improved, but data processing time and computational load increase
Solution Approach 1:
The patent performs preliminary processing of MRI data by pre-identifying fiduciary landmarks and establishing their spatial relationships before they are needed for real-time control. This preparation work is done in advance, reducing the computational burden during actual robot positioning operations.
Solution Approach 2:
The patent focuses on detecting and processing only the essential fiduciary landmarks that are critical for positioning, rather than processing all MRI data. This selective approach provides sufficient positioning precision while minimizing computational time and processing load.
Data Source
AI summary
An exemplary robotic system and control method is disclosed that employs magnetic-resonance imaging (MRI) guided visual-servo positioning of a medical robot system. In an example, an MR Elastography (MRE) actuator system is disclosed that employs the exemplary MRI-guided visual servoing to assess tissues based on its mechanical properties. The exemplary MRI-guided positioning is directly and solely used as a feedback sensor through its visual output to control multiple degrees of movement of the MRE actuators. The exemplary MRI-guided positioning may be employed in various diagnostics, minimally invasive surgery, or medical procedures for any number of a medical instrument and interventional procedures that can be conducted in an MRI environment or in proximity to an MRI scanner.