MRI Actuator Positioning via Flexible Coupling
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Solution Overview
Problem
Current MRI-compatible robotic systems face challenges in minimizing magnetic and electromagnetic interferences, which can disrupt the functionality of actuators and pose safety risks, especially in high-field MRI scanners used for small animal studies, limiting precise targeting of brain nuclei.
Innovation Solution
A positioning system with actuators positioned at a distance D from the MRI bore, coupled to the insertion element through form-fit and force-fit mechanisms, using conventional actuators like step motors and piezo motors to minimize interference, and employing belt drives for precise movement control, allowing for accurate targeting of deep brain nuclei.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If actuators are placed close to the MRI bore for precise positioning, then positioning precision is improved, but magnetic and electromagnetic interferences increase causing safety risks and functional disruption
Solution Approach 1:
The actuator is positioned outside the MRI bore (spatial dimension change) and connected to the insertion element through a flexible coupling mechanism. This separates the actuator from the high magnetic field region while maintaining positioning capability through the coupling mechanism that transmits motion across the boundary.
Solution Approach 2:
A flexible coupling mechanism acts as an intermediary between the actuator and the insertion element. This intermediary transmits the actuating force and motion while isolating the actuator from the harmful magnetic and electromagnetic environment inside the bore, solving both precision and safety requirements.
2Device complexity
If conventional actuators are used to reduce cost and complexity, then device complexity is reduced, but magnetic and electromagnetic interferences increase
Solution Approach 1:
The actuator is extracted from the MRI bore environment and placed outside. This removes the conventional actuator (which would be complex and expensive to make MRI-compatible) from the harmful magnetic field region, allowing use of simple, low-cost conventional actuators while maintaining system functionality through the coupling mechanism.
Solution Approach 2:
The functional capability of MRI-compatible actuation is achieved by copying the motion transmission function through a flexible coupling mechanism, rather than using expensive specialized MRI-compatible actuators. This allows conventional actuators to perform the required function at lower cost and complexity.
3Reliability
If actuators are positioned at a distance from the bore to minimize interference, then safety and functionality are improved, but positioning accuracy may deteriorate
Solution Approach 1:
The direct mechanical connection between actuator and insertion element is replaced with a flexible coupling mechanism. This substitution allows the actuator to be positioned at a safe distance while the coupling mechanism transmits the actuating force with sufficient precision to maintain targeting accuracy, bridging the gap between safety distance and positioning precision.
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 and safe targeting of brain nuclei with high accuracy and low costs, compatible with high-field MRI scanners, and adaptable to small animal models, overcoming the limitations of existing systems.
Implementation Method 1
said at least one actuator is arranged with a distance D from the bore to minimize magnetic and/or electromagnetic interferences between the imaging device and the at least one actuator
Implementation Method 2
said at least one actuator is arranged with a distance D from the bore to minimize magnetic and/or electromagnetic interferences between the imaging device and the at least one actuator
Data Source
AI summary
A positioning system for an imaging device, in particular a MR imaging device to position an insertion element on or in the body of a subject, in particular an animal, wherein the imaging device comprises a bore, in which the subject is received, wherein the positioning system comprises a robot which can be at least partially arranged in the bore of the imaging device and comprises a holding element to hold the insertion element; wherein the robot further comprises at least one actuator acting on the holding element, such that an end portion of the insertion element is movable, wherein said at least one actuator is arranged with a distance D from the bore to minimize magnetic and/or electromagnetic interferences between the imaging device and the at least one actuator and said first actuator is coupled to the holding element in a form-fit- and/or a force-fit-manner.