Surgical Navigation Registration Assembly
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Solution Overview
Problem
The existing methods for registering physical world space with imaging space in surgical navigation systems are time-consuming and burdensome for surgeons, requiring extensive effort to correlate positions and directions in the physical world with scanned image space.
Innovation Solution
A method involving an assembly with positional and directional objects, measured and tracked using a tracking tool, allowing for the computation of transformations to convert positions and directions from the physical world into the imaging space without prior calibration, using a combination of electromagnetic or optical tracking systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing registering methods are used to map physical world space with imaging space, then the transformation can be obtained to correlate positions, but the process requires extra time and extra burden for surgeons to identify and correlate positions and directions
Solution Approach 1:
The patent applies preliminary action by pre-defining the geometric relationships between positional objects and directional objects in the assembly before the surgical procedure. The measuring piece is pre-calibrated with the tracking tool, and the transformation between physical space and image space is pre-computed based on the known geometric constraints. This eliminates the need for surgeons to perform time-consuming iterative identification and correlation during the actual registering process, as the transformation can be directly applied once the assembly is positioned.
2Measurement precision
If existing registering methods are used to correlate physical world space with imaging space, then the transformation can be computed, but the process imposes extra burden on surgeons to identify positions and directions
Solution Approach 1:
The patent implements self-service by designing the assembly to automatically establish the coordinate transformation without requiring surgeon intervention for identification and correlation. The positional objects and directional objects are rigidly connected with known geometric relationships, allowing the system to self-determine the transformation matrix. The measuring piece automatically measures the positions and directions of objects relative to the tracking tool frame, and the computer automatically computes the transformation, freeing the surgeon from complex manual operations.
Solution Approach 2:
The patent introduces an intermediary measuring piece that serves as a mediator between the tracking tool and the objects to be measured. The measuring piece contains measurement markers that can be detected by both the tracking system and the imaging system, establishing a common reference framework. This intermediary element simplifies the surgeon's task by providing a straightforward correlation path: objects are measured relative to the measuring piece, which is tracked relative to the assembly, which is positioned on the patient body.
3Measurement precision
If a measuring piece with prior calibration is used, then accurate measurement can be achieved, but the calibration process adds complexity and time to the preparation
Solution Approach 1:
The patent applies preliminary action by pre-establishing the geometric relationships between the measuring piece and the tracking tool during the design and manufacturing phase. The measuring piece is fabricated with precisely known positions of measurement markers relative to the tracking tool attachment points. This pre-calibration eliminates the need for complex runtime calibration procedures, as the geometric constraints are inherently built into the physical structure of the assembly.
Solution Approach 2:
The patent changes the approach from dynamic calibration to static geometric constraint-based measurement. Instead of performing iterative calibration procedures to determine transformation parameters, the system uses pre-defined geometric parameters (positions of positional objects, orientations of directional objects) that are fixed by the rigid mechanical structure. The computer computes the transformation by solving geometric equations based on these fixed parameters and the measured positions, rather than through iterative calibration adjustments.
Data Source
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AI summary
Methods for measuring and registering positions and directions in image space with that in world space includes: providing an assembly with a tracking tool; the assembly including positional and/or directional objects with positions and available directions measured according to the tracking tool's frame with a measuring piece having a measuring surface for measuring without prior calibration with a measuring tracking tool in a tracking system; placing the assembly on a body and perform scanning; placing a relative tracking tool at the body; in registering time, recording the data for both the relative tracking tool and the tracking tool attached to the assembly; placing a tracking tool on an instrument; in post-registering time, recording both data of the tracking tool attached on the instrument and data of the relative tracking tool; computing converted positions and/or available directions of the tracking tool attached on the instrument in the image space.