X-Ray Ripple Markers for Accurate C-Arm Registration
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Solution Overview
Problem
Existing C-arm registration methods for mobile X-ray systems in minimally invasive surgeries lack accuracy and reliability, hindering advanced imaging and 3D measurements due to the need for additional hardware and impacting surgical workflow.
Innovation Solution
A X-ray ripple marker that generates X-ray imaged waves with characteristics dependent on the C-arm's pose, utilizing features like copper or steel balls to enhance registration algorithm robustness, allowing for precise C-arm registration without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If hardware tracking markers (optical or inertial) are installed on the C-arm, then C-arm registration accuracy is improved, but device complexity and workflow impact worsen due to multiple components and installation requirements
Solution Approach 1:
The patent extracts the registration marker from the C-arm itself and places it on the patient table or operating room floor instead. This separates the marker from the C-arm, eliminating the need for complex hardware installation on the C-arm while maintaining registration accuracy through the ripple pattern's geometric features
Solution Approach 2:
The patent replaces mechanical/optical tracking markers with an X-ray-based ripple pattern that is imaged directly by the C-arm's own imaging system. This substitution eliminates the need for separate optical tracking hardware and integrates the registration function into the existing X-ray imaging pathway
2Measurement precision
If traditional markers (steel balls or geometric features) are used for C-arm registration, then registration can be performed, but measurement precision and reliability are insufficient for advanced imaging and 3D measurements
Solution Approach 1:
The patent transforms the registration marker from discrete geometric features (steel balls, cubes) into a continuous ripple pattern with specific frequency, amplitude, and phase parameters. These wave parameters provide richer information for pose estimation, improving both accuracy and reliability for advanced imaging applications
Solution Approach 2:
The ripple pattern combines multiple sinusoidal wave components with different frequencies and orientations to create a composite pattern that provides robust registration information from multiple directions, enhancing reliability compared to single-feature markers
3Measurement precision
If a marker with multiple opaque features is used for accurate registration, then measurement precision improves, but productivity worsens due to workflow disruption and image quality impact
Solution Approach 1:
The ripple pattern uses subtle variations in radiographic density (analogous to color changes) rather than opaque features. This allows the marker to be visible for registration purposes while remaining transparent to the surgical workflow and not obscuring the patient anatomy in the X-ray images
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
Enables accurate and reliable C-arm registration, facilitating advanced imaging and 3D measurements by determining the C-arm's position and orientation relative to a fixed coordinate system, improving surgical precision and workflow efficiency.
Implementation Method 1
generate an X-ray image of features of the marker to perform the C-arm Registration
Data Source
Figure 1~2D
Figure 3A~3B
Figure 4A
AI summary
Various embodiments of the present disclosure include a C-arm registration system employing a controller (70) for registering a C-arm (60) to an X-ray ripple marker (20) including a ripple pattern (50) radially extending from a fixed point (40) of the X-ray ripple marker (20). In operation, the controller (70) identifies the ripple pattern (50) within an X-ray image generated from an X-ray projection by the C-arm (60) and illustrative of a portion or an entirety of the ripple pattern (50), the identification of the ripple pattern (50) within the X-ray image is characteristic of a pose of the X-ray projection by the C-arm (60) relative to the X-ray rippler marker (20). The controller (70) further analyzes the ripple pattern (50) within the X-ray image to derive one or more transformation parameters definitive of the pose of the X-ray projection by the C-arm (60) relative to the X-ray rippler marker (20), and registers the C-arm (60) to the X-ray ripple marker (20) based on the transformation parameter(s).