Coordinate Transformation for Navigation-Guided Procedures
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Solution Overview
Problem
Existing navigation-guided medical procedures face challenges in accurately determining coordinate transformation between imaging diagnostic tools and position-determining systems, particularly due to interference from sterile covers and inconsistent marker detection, which limits accuracy and compatibility with various position-determining systems.
Innovation Solution
A system and method utilizing a spatial reference structure on the imaging diagnostic tool, contacted by a pointer with detectable markers, to calculate a transformation matrix recursively, allowing precise alignment between the imaging diagnostic tool and position-determining system, even with a sterile cover film in place, and accommodating various position-determining systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If markers are arranged on the X-ray radiation receiver for position determination, then the position-determining system can detect markers, but the sterile cover film interferes with marker detection and reduces accuracy
Solution Approach 1:
The patent introduces a separate reference structure as an intermediary element that can be contacted by the pointer. This reference structure is distinct from the X-ray radiation receiver, allowing position determination without requiring markers to be directly on the receiver surface where sterile cover interference occurs. The pointer contacts the reference structure to establish coordinate transformation, bypassing the sterile cover barrier.
Solution Approach 2:
The system separates the reference structure from the X-ray radiation receiver into distinct components. The reference structure is a separate element that can be contacted independently, allowing the pointer to determine position through contact with this separate structure rather than relying on markers on the receiver surface that are blocked by sterile cover.
2Adaptability or versatility
If markers are arranged on the X-ray radiation receiver, then position determination is possible, but the system cannot operate with other position-determining systems without mechanical modifications
Solution Approach 1:
The reference structure is designed as a universal interface that can work with different types of position-determining systems. Instead of integrating system-specific markers into the X-ray radiation receiver, the patent uses a standardized reference structure with known geometry that can be contacted by a pointer detected by various position-determining systems (electromagnetic, optical, mechanical), making the system adaptable without mechanical modifications to the imaging device.
3Measurement precision
If a reference structure is detachably connected to the X-ray radiation receiver for registration, then coordinate transformation can be performed, but the added mass affects C-arm kinematics and torsion
Solution Approach 1:
The patent extracts the reference structure determination process from the physical C-arm assembly. Instead of attaching a heavy reference structure to the C-arm that would affect its mass distribution and kinematics, the system uses a lightweight reference structure on the X-ray radiation receiver that is determined through pointer contact. This separates the registration function from the mechanical C-arm structure, eliminating the mass and stability issues.
4Measurement precision
If multiple markers are used on the imaging device for position determination, then detection accuracy may improve, but the system complexity and cost increase
Solution Approach 1:
Instead of using multiple physical markers on the imaging device, the patent uses a single reference structure with known geometry that is contacted by a pointer. The pointer tip position is determined by the position-determining system, and this single contact point combined with the known reference structure geometry provides sufficient information for coordinate transformation without requiring multiple markers, thereby reducing system complexity and cost.
Data Source
AI summary
The invention relates to a method and device for performing coordinate transformation for navigation-guided procedures using an imaging diagnostic tool, especially an X-ray diagnostic tool, and a position-determining system. In the vicinity of the image receiver, the diagnostic tool has one or more three-dimensional reference structure that can be touched with a pointer of a position-determining system. From the known geometry of the three-dimensional reference structure and the coordinates of the touched points determined by the position-determining system, a coordinate transformation is created between the coordinate system of the diagnostic tool and the coordinate system of the position-determining system. Navigation for an instrument captured by the position-determining system can be performed in reconstructed images of the diagnostic tool after the registration procedure.