Calibration Selection Module for EM Field Generator Positioning
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Solution Overview
Problem
In interventional procedures, the variability in patient size and clinical factors makes it challenging to achieve a consistent position and orientation of the electromagnetic field generator, leading to sub-optimal performance and errors in EM-US fusion during calibration.
Innovation Solution
A system and method that utilize a data structure with pre-computed calibrations for different positions and orientations of the field generator, indexed to a reference sensor, allowing for the selection of the optimal calibration based on real-time monitoring and matching of the sensor's position and orientation, ensuring accurate and robust placement of the field generator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single calibration is performed during controlled settings, then calibration accuracy is achieved under ideal conditions, but system performance deteriorates when field generator position and orientation vary from calibration settings
Solution Approach 1:
Multiple calibrations are performed in advance during controlled settings, each at different field generator positions and orientations. These pre-computed calibrations are stored in a data structure indexed by position and orientation parameters. During the interventional procedure, the system automatically selects the appropriate pre-computed calibration based on the actual field generator position, eliminating the need for real-time calibration adjustments and ensuring optimal performance under varying clinical conditions.
2Reliability
If field generator position is fixed during calibration, then calibration validity is maintained, but adaptability to different patient geometries and clinical factors is lost
Solution Approach 1:
The system performs calibrations at multiple discrete field generator positions and orientations, storing each calibration with its associated position and orientation parameters. During the procedure, the system changes the selected calibration parameter based on the actual field generator position, allowing the system to adapt to different patient geometries and clinical factors while maintaining calibration validity for each specific configuration.
3Reliability
If multiple calibrations are performed for different positions and orientations, then system robustness to position changes is improved, but calibration selection complexity increases
Solution Approach 1:
The system automatically monitors the field generator position and orientation in real-time and autonomously selects the appropriate pre-computed calibration from the data structure based on the current position parameters. This self-service mechanism eliminates the need for manual calibration selection by operators, reducing the perceived complexity despite the underlying robust multi-calibration framework.
4Measurement precision
If calibration is performed in controlled settings, then measurement precision is achieved, but ease of operation in actual clinical procedures is reduced
Solution Approach 1:
All calibration activities are performed in advance during controlled settings with precise positioning. The multiple calibrations covering various field generator positions and orientations are completed beforehand and stored in an indexed data structure. During the actual interventional procedure, the system automatically selects the appropriate calibration based on the current position, requiring no additional calibration operations from the operator and maintaining both precision and ease of operation.
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
Ensures accurate and robust placement of the field generator, insensitive to position and orientation changes, thereby maintaining optimal calibration and fusion between tracking devices and images throughout the procedure, even under varying clinical conditions.
Implementation Method 1
an EM field generator (FG) is provided near an area of the procedure
Implementation Method 2
The magnetic field generator is driven so as to generate a magnetic field and the probe is moved in a predetermined, known orientation
Data Source
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AI summary
A system for selecting a calibration includes a data structure (138) including non- transitory computer readable storage media having a plurality of calibration entries stored therein and indexed to position and/or orientation criteria for a field generator. The field generator is configured for placement in an environment for sensor tracking. A calibration selection module(140)is configured to determine a position and/or orientation of the field generator and, based on the position and/or orientation, determine, using the data structure, corresponding calibration information stored in the data structure. The calibration information is optimized based upon the position and/or orientation of the field generator.