Optical Shape Sensing System for Interventional Instruments

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Solution Overview

Problem

Current medical devices lack reliable and flexible systems for integrating optical shape sensing structures in interventional environments, which are essential for accurate strain and temperature measurement during medical procedures, and existing technologies face challenges in optimizing fiber length, coherence length, and data processing for precise shape reconstruction.

Innovation Solution

An integrated optical shape sensing system with a multi-core fiber connector arrangement and an optical interrogation module, where fiber ports or connectors are trackable to provide a known reference position for accurate shape reconstruction, and an optical shape sensing enabled interventional instrument with first and second optical fiber cables connected to these ports for precise feedback collection and imaging registration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If fiber length is increased to improve measurement range, then coherence length requirements become more stringent and system complexity increases

Engineering Contradiction:
Improvefiber lengthVSAvoidcoherence length maintenance
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts the optical interrogation parameters including wavelength sweep range and sampling rate based on the actual fiber length and coherence characteristics. This allows optimization of measurement performance for different fiber lengths without compromising coherence requirements, resolving the contradiction between extended measurement range and coherence maintenance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system implements dynamic configuration of the optical interrogation module where the wavelength sweep characteristics are adaptively adjusted according to the measured fiber properties. This dynamic adaptation enables the system to maintain reliable measurements across varying fiber lengths while managing coherence length constraints.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If multiple fiber cables are integrated to improve shape reconstruction accuracy, then device complexity and connection requirements increase

Engineering Contradiction:
Improveshape reconstruction accuracyVSAvoidconnector arrangement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system divides the shape sensing function into multiple independent fiber channels, each carrying strain and temperature measurements. This segmentation allows parallel processing of multiple spatial measurements and enables independent optimization of each fiber path, reducing the complexity of individual connections while improving overall reconstruction accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The optical interrogation module is designed with universal connectivity that can accommodate multiple fiber cables through a standardized interface. This multi-functional design allows the same interrogation system to handle various fiber configurations and lengths, reducing the need for specialized connection arrangements for each fiber.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If data processing is enhanced to improve measurement precision, then processing time and computational resources increase

Engineering Contradiction:
Improvestrain and temperature measurement precisionVSAvoiddata processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary calibration and reference pattern acquisition during setup, storing processed reference data for rapid comparison during actual measurements. This preliminary processing eliminates the need for complex real-time calibration, significantly reducing measurement processing time while maintaining high precision through pre-computed reference frames.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements real-time feedback processing where measurement data is continuously compared with reference patterns and processed through optimized algorithms. The feedback mechanism allows for adaptive processing that adjusts computational intensity based on signal quality and measurement requirements, balancing precision with processing speed.

Inventive Principle:
Principle #23Feedback

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 system enables accurate and flexible shape reconstruction in interventional environments, optimizing fiber length and coherence length for precise strain and temperature measurement, enhancing the accuracy and efficiency of medical procedures by providing a reliable tracking system for instruments within the clinical setting.

Implementation Method 1

Shape sensing based on fiber optics equates to distributed strain measurement in optical fibers with characteristic Rayleigh scatter patterns. Rayleigh scatter occurs as a result of random fluctuations of the index of refraction in the fiber core, inherent to the fiber manufacturing process.

Methodology Applied
Scientific EffectRayleigh scattering: Rayleigh Scattering

Implementation Method 2

Cross-correlation of the Rayleigh scatter spectra of the fiber in the strained / unstrained states determines the spectral shift resulting from the applied strain.

Methodology Applied
Scientific EffectCross-correlation:

Implementation Method 3

In OFDR, the laser wavelength or optical frequency is linearly modulated over time. For coherent detection, the backscattered wave is mixed with a coherence reference wave at the detector.

Methodology Applied
Scientific EffectOptical frequency modulation: Phase Modulation

Implementation Method 4

For coherent detection, the backscattered wave is mixed with a coherence reference wave at the detector. The detector receives a modulated signal owing to the change of constructive to destructive interference and vice versa while scanning the wavelength.

Methodology Applied
Scientific EffectCoherent detection: Homodyne Detection

Data Source

PatentEP2667815B1Integration of fiber optic shape sensing within an nterventional environment
Publication Date: 2018.11.14 KONINKLIJKE PHILIPS NV
  • EP2667815B1 patent drawingFigure 1
  • EP2667815B1 patent drawingFigure 2A~2B
  • EP2667815B1 patent drawingFigure 3~6

AI summary

An integrated optical shape sensing system and method include an arrangement structure (132) configured to receive a fiber port or connector. A platform (130) is configured to provide a distance relationship with the arrangement structure such that the fiber port or connector is trackable to provide a location reference. The platform secures a patient in proximity to the arrangement structure. An optical shape sensing enabled interventional instrument (102) has a first optical fiber cable connectable to the fiber port or connector. An optical interrogation module (108) is configured to collect optical feedback from the instrument and has a second optical fiber cable connectable to the fiber port or connector such that a known reference position is provided for accurate shape reconstruction.