Optical Fiber Collision Detection for MRI Magnet Safety

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Solution Overview

Problem

Existing collision detection systems for MRI systems using cylindrical magnets are not compatible with the magnetic and RF field requirements, and previous technologies are not suitable for use in MRI environments, posing safety risks for patients and surgical teams.

Innovation Solution

A fiber-optic collision detection system is integrated into the MRI magnet, utilizing a flexible body with optical fibers that bend upon impact, allowing for detection of collisions without interfering with the magnetic field, and featuring a resilient under layer and stiffer surface layer to adjust sensitivity and spatial resolution, with a foam layer for cushioning and a cleanable coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional collision detection systems are used in MRI systems, then collision detection capability is provided, but compatibility with magnetic and RF field requirements is lost

Engineering Contradiction:
Improvecollision detection capabilityVSAvoidcompatibility with magnetic and RF field requirements
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces traditional mechanical or electronic collision detection systems with an optical fiber-based detection system. The optical fiber sensor detects collisions through changes in light transmission properties when bent by impact forces, eliminating the need for mechanical components or electronic sensors that would be incompatible with MRI's magnetic and RF fields.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces optical fiber as an intermediary element that mediates between the physical collision event and the detection system. The optical fiber translates mechanical impact into optical signal changes (light transmission variations) that can be detected and processed, providing indirect collision detection that is compatible with MRI environmental constraints.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a detection device is mounted on the magnet, then collision detection is enabled, but magnetic field homogeneity may be affected

Engineering Contradiction:
Improvecollision detection functionVSAvoidmagnetic field homogeneity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent replaces mechanical or electronic detection components with optical fiber sensors that do not contain metallic or magnetically sensitive elements. The optical fiber is embedded in a flexible body mounted on the magnet surface, detecting collisions through light transmission changes without introducing magnetic field disturbances.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses a flexible body (such as a foam layer or flexible membrane) as the mounting structure for the optical fiber sensor. This flexible body is attached to the magnet surface and deforms upon collision, causing optical fiber bending that triggers detection. The flexible material is non-magnetic and does not interfere with field homogeneity while providing effective collision sensing.

Inventive Principle:
Principle #30Flexible shells and thin films

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 system effectively detects collisions without affecting the MRI's magnetic field homogeneity, is MR-compatible, and can differentiate between various contact levels, ensuring patient and surgical team safety by communicating with the magnet mover control system.

Implementation Method 1

the detection device (20) comprising a flexible body within which is mounted at least one optical fiber (35) arranged such that the impact causes bending of the optical fiber (35); and detecting changes in light transmission through the at least one optical fiber (35) to detect the bending and thus the collision

Methodology Applied
Scientific EffectOptical fiber bending detection: Optical Fibre

Data Source

PatentEP2002217B1Detection of collisions in medical procedures
Publication Date: 2020.08.26 IMRIS INC(CA)
  • EP2002217B1 patent drawingFigure 1
  • EP2002217B1 patent drawingFigure 2
  • EP2002217B1 patent drawingFigure 3

AI summary

A method of detecting collisions between elements in a medical procedure such as between a magnet and another element in the procedure mounting on the medical device a flexible body within which is mounted one or more parallel side by side optical fibers arranged such that the impact causes bending of one or more of the optical fibers and detecting changes in light transmission through the optical fiber to detect the bending and thus the collision. The single fiber or fibers are located in a junction between a lower body of resilient foam and a surface layer of a stiffer flexible material.