Catheter Force Calibration via Rolling Element Redirection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Invasive probes, such as catheters, face challenges in accurately measuring contact force due to varying relationships between actual contact force and sensor measurements, necessitating a reliable calibration method to ensure precise force measurement across different angles of contact with body tissue.
Innovation Solution
A calibration system using a flexible silicone rubber ball and a sensing device to redirect and measure forces applied by the catheter's distal tip, allowing for the computation of calibration coefficients that translate distortion measurements into accurate force readings, which are stored for later use during medical procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a force sensor is embedded in the catheter to measure contact pressure, then contact force measurement capability is improved, but measurement precision deteriorates due to varying relationships between actual contact force and sensor measurements across different angles
Solution Approach 1:
The patent applies preliminary action by performing calibration before actual use. A calibration curve is pre-established by measuring the relationship between distal tip distortion and actual contact force at multiple angles using a calibration apparatus. This pre-established calibration data is then used to correct sensor readings during actual procedures, ensuring accurate force measurement across varying contact angles.
Solution Approach 2:
The patent changes parameters by measuring distal tip distortion at multiple different angles of contact (e.g., 0°, 45°, 90°) during calibration. By collecting data across multiple angular parameters, the system establishes a comprehensive calibration model that accounts for angle-dependent variations in force measurement, thereby improving precision across all operating conditions.
2Measurement precision
If calibration is performed to improve measurement precision across multiple angles, then accuracy is improved, but device complexity increases due to the need for calibration apparatus and procedures
Solution Approach 1:
The patent uses an intermediary approach by introducing a calibration apparatus that includes a spherical object and a distortion measurement device. This intermediary calibration system allows for the establishment of calibration curves without requiring complex integration into the final catheter product. The calibration apparatus serves as a separate, standalone system that simplifies the overall device complexity while still enabling precise calibration.
3Reliability
If distortion measurements are used to determine contact force, then force measurement capability is improved, but measurement precision deteriorates due to variation in the relationship between distortion and actual force at different angles
Solution Approach 1:
The patent applies preliminary action by pre-establishing calibration curves that capture the relationship between distal tip distortion and actual contact force at multiple angles. These calibration curves are determined before actual use through systematic measurement using a calibration apparatus. During actual procedures, the pre-established calibration data is used to accurately translate distortion measurements into contact force values, ensuring consistent and reliable measurements across varying angles.
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 consistent force measurement across multiple angles of contact, ensuring precise control of force exerted by the catheter on body tissue, thereby improving the reliability of medical procedures by providing high-accuracy force data.
Implementation Method 1
a sensing device for sensing a downward force exerted by the distal tip on the planar surface
Implementation Method 2
a flexible, resilient rolling element, such as a silicone rubber ball, resting on a planar horizontal surface coupled to a sensing device
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An apparatus, consisting of a rolling element (46), which is resting on a surface (48), and a force-sensing device (50), which is coupled to the surface. The force-sensing device is configured to make a first measurement indicative of a force exerted in a direction perpendicular to the surface. The force is exerted by a force-sensing probe (26) pressing against the rolling element so as to hold the rolling element stationary. The apparatus further includes a calibration processor, which is configured to collect the first measurement from the sensing device, to collect a second measurement indicative of the force from the force-sensing probe, and to calibrate the force-sensing probe based on the first and second measurements.