Position Determination Device for Tubular Structures
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Solution Overview
Problem
Existing position determination methods for elongated medical instruments within tubular structures, such as catheters or bronchoscopes, face inaccuracies due to inhomogeneities in electromagnetic fields and errors in interpolation and integration of curvature information, limiting their precision.
Innovation Solution
A position determination device that provides local distributions of curvature and strain values along a path within the tubular structure, allowing for precise positioning of instruments by comparing these values with pre-determined or simulated data, reducing sensitivity to global measurement errors and eliminating the need for shape reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electromagnetic tracking or optical shape sensing is used to determine instrument position, then positioning capability is provided, but measurement precision deteriorates due to field inhomogeneities and interpolation errors
Solution Approach 1:
The patent divides the continuous curvature profile into discrete local curvature segments at multiple measurement points along the instrument. By comparing these segmented local curvature values with pre-measured curvature profiles of the tubular structure, the system achieves more accurate position determination that is less sensitive to global measurement errors and field inhomogeneities.
Solution Approach 2:
The invention focuses on measuring and comparing local curvature characteristics at specific points along the instrument rather than relying on global shape reconstruction. This local approach uses curvature values at multiple discrete locations to determine position, making the measurement less vulnerable to cumulative errors and inhomogeneities in the electromagnetic or optical fields.
2Measurement precision
If global shape reconstruction is performed to determine instrument position, then complete position information is obtained, but measurement precision deteriorates due to cumulative errors in interpolation and integration
Solution Approach 1:
The patent extracts only the essential local curvature information at multiple points along the instrument, eliminating the need for complete global shape reconstruction. By comparing these extracted local curvature characteristics with pre-measured profiles of the tubular structure, the system determines instrument position without the cumulative errors associated with full shape integration and interpolation.
3Ease of operation
If electromagnetic or optical tracking systems are used, then positioning functionality is provided, but device complexity increases due to field inhomogeneities and calibration requirements
Solution Approach 1:
The system creates a pre-measured curvature profile map of the tubular structure before the intervention procedure. During the procedure, only local curvature measurements at discrete points need to be taken and compared against this pre-existing map, significantly simplifying the real-time operation while maintaining high positioning accuracy without complex global tracking requirements.
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 approach significantly enhances the accuracy of instrument positioning within tubular structures by using local information, reducing sensitivity to measurement errors and allowing for precise determination without requiring shape reconstruction, thus improving navigation and intervention accuracy.
Implementation Method 1
Optical shape sensing is typically performed by evaluating multiple optical curvature sensors, which in turn are composed of strain sensors arranged concentrically around the fiber's cross-section
Data Source
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AI summary
The invention relates to a position-determining device (5) for determining the position of an elongate object (4) within a tubular structure. The position-determining device (5) comprises a first providing unit (6) for providing a first distribution of curvature values at a plurality of first points along a path within the tubular structure. The position-determining device (5) also comprises a second providing unit (7) for providing a second distribution of extension values or curvature values at a plurality of second points along the object (4) and a position-determining unit (8) for determining the position of the object (4) relative to the path on the basis of the first and second distributions.