Slip Ring Overlapping Conductors MRI Interference
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Solution Overview
Problem
Magnetic resonance imaging (MRI) systems face interference from magnetic fields generated by slip rings used to supply electrical power to medical devices like linear accelerators, which can degrade MR image quality.
Innovation Solution
A slip ring assembly design featuring overlapping cylindrical conductors with electrically isolated layers and slits to confine current flow, reducing the magnetic field interference by canceling out the magnetic fields generated by the conductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If significant amounts of electrical current are supplied to the medical device through the slip ring assembly, then the medical device can be powered adequately, but the currents generate a magnetic field that affects the measurements made by the magnetic resonance imaging system
Solution Approach 1:
The patent applies the principle of converting harm into benefit by using the magnetic fields generated by the conductors to cancel each other out. The harmful magnetic field interference is transformed into a beneficial cancellation effect, where the combined magnetic field from multiple conductors reduces the net interference with MRI measurements while maintaining adequate power supply to the medical device.
Solution Approach 2:
The patent merges multiple conductors into a single slip ring assembly structure. By positioning conductors within the assembly and allowing their magnetic fields to interact, the design combines individual conductor effects to achieve reduced net magnetic field interference while delivering the required electrical power to the medical device.
2Power
If conventional slip rings are used to supply power to rotating medical devices, then electrical power can be transmitted, but the magnetic field generated degrades MR image quality
Solution Approach 1:
The patent converts the harmful magnetic field effect into a beneficial cancellation mechanism. By carefully positioning multiple conductors within the slip ring assembly, the magnetic fields they generate interfere destructively, reducing the net magnetic field that would otherwise degrade MR image quality while maintaining power transmission capability.
Solution Approach 2:
The patent changes the physical parameters of the conductor arrangement within the slip ring assembly. By modifying the position, orientation, and configuration of conductors, the design alters the magnetic field distribution to achieve reduced net field strength, thereby improving MR image quality while maintaining adequate power transmission to the rotating medical device.
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 design effectively minimizes magnetic field interference, maintaining high-quality MRI images even when significant electrical current is supplied to medical devices, such as linear accelerators, during radiation therapy.
Implementation Method 1
positioning conductors within a slip ring assembly to reduce magnetic field generated by the slip ring assembly. Embodiments use cylindrical conductors that overlap such that the magnetic field that is generated is reduced.
Data Source
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AI summary
A medical apparatus (600) including: a magnetic resonance imaging system (602), a medical device (634), and a slip ring assembly (400, 500) for supplying electrical power to the medical device. The slip ring assembly includes: a cylindrical body (100), a rotating member (402) for rotating the medical device, a first cylindrical conductor attached to the cylindrical body, a second cylindrical conductor (108), a first set of conductive elements (112, 712) connected to the second cylindrical conductor; and a brush assembly (406) comprising a first brush (302) and a second brush (304). The first brush is operable to contact the first cylindrical conductor. The second brush is operable to contact the set of conductive elements. The first and second cylindrical conductive elements overlap at least partially. The second cylindrical conductor is connected to the cylindrical body. The first cylindrical conductor and the second cylindrical conductors are electrically isolated.