On-the-fly Catheter Calibration via Sensitivity Table
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Solution Overview
Problem
The existing calibration methods for magnetic catheter-based location and orientation tracking systems are time-consuming and costly, limiting mass production and requiring individual factory calibration of each catheter, which increases the risk of errors during clinical procedures.
Innovation Solution
A method that estimates calibration values for a magnetic position sensor during a catheterization procedure using a stored sensitivity table and sensor readings, allowing for on-site calibration of the catheter's location and orientation, reducing the need for initial factory calibration and enabling efficient mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If individual factory calibration is performed for each catheter, then calibration accuracy is improved, but calibration time and cost increase
Solution Approach 1:
A sensitivity table is pre-calculated and stored in memory, containing calibration data for multiple orientations. During the procedure, the system performs rapid on-the-fly calibration by retrieving this pre-prepared sensitivity table and applying it to the specific catheter, eliminating the need for time-consuming factory calibration of each individual catheter while maintaining accuracy
Solution Approach 2:
The system performs self-calibration during the catheterization procedure itself. The magnetic position sensor automatically calibrates by utilizing the pre-stored sensitivity table and performing measurements in the organ, allowing calibration to occur without external intervention or separate factory calibration steps
2Measurement precision
If individual factory calibration is performed for each catheter, then calibration accuracy is improved, but manufacturing cost increases
Solution Approach 1:
A single sensitivity table serves as a universal calibration resource for multiple catheters. The pre-calculated sensitivity table contains orientation-dependent calibration data that can be applied to any catheter with a magnetic position sensor, eliminating the need for separate factory calibration equipment and processes for each catheter model
Solution Approach 2:
The system replaces expensive individual factory calibration processes with a low-cost software-based calibration approach. The sensitivity table is a digital asset that can be reused indefinitely without degradation, significantly reducing per-unit calibration costs while maintaining accuracy
3Loss of time
If rapid on-the-fly calibration is performed during procedure, then calibration time is reduced, but calibration complexity increases
Solution Approach 1:
The complex sensitivity table calculation is performed in advance during system setup or manufacturing. The table contains pre-computed calibration data for multiple orientations that simplifies the runtime calibration process to mere data retrieval and application, reducing on-the-fly computational complexity
Solution Approach 2:
The calibration approach transitions from real-time computational calibration to a lookup-based approach using pre-stored orientation-dependent calibration data. By organizing calibration information in a multi-dimensional sensitivity table indexed by orientation, the system trades computational complexity for efficient data retrieval
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 allows for rapid and accurate calibration of catheters in less than a second at the beginning of a procedure, reducing errors and enabling universal initial calibration, thus facilitating efficient mass production and reducing the risk of catheter mispositioning during clinical use.
Implementation Method 1
measure field strengths of magnetic fields generated by two or more field generators
Data Source
AI summary
A method includes retrieving from a memory a stored sensitivity table that associates magnetic position sensor readings with measured magnetic fields. One or more calibration values for the magnetic position sensor are estimated during a catheterization procedure in which a magnetic position sensor, fitted at a distal end of a catheter, is placed in an organ of a patient, based on (i) the stored sensitivity table and (ii) readings acquired by the magnetic position sensor while in the organ. Based on the one or more calibration values, a location of the distal end in the organ is magnetically tracked.