Robotic Catheter Pose Measurement Using Segmented EM and Fiber Sensors
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Solution Overview
Problem
Manufacturing a catheter that is small enough to navigate through body lumens with diameters as small as 3 mm or less, while incorporating mechanical and sensor structures for remote operation, is challenging due to the need for a tool mount, steerable segment, suction and irrigation lumens, vision system, and sensors for precise anatomy alignment.
Innovation Solution
A robotic catheter system utilizing a combination of electromagnetic and fiber sensors, where a thicker proximal section contains EM sensors for base point measurement and a thinner distal section uses fiber shape sensors for accurate pose measurement, allowing the distal tip to be as small as 3 mm without incurring the inaccuracies of long fiber shape sensors, and featuring a removable vision probe for interchangeable functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a catheter is made small enough to navigate through body lumens with diameters as small as 3 mm or less, then the catheter can access target locations in small passages, but it becomes difficult to accommodate all necessary features including tool mount, steerable segment, suction and irrigation lumens, vision system, and sensors
Solution Approach 1:
The catheter is divided into multiple functional segments: a proximal section containing electromagnetic sensors for pose measurement, a distal section with fiber shape sensors for shape measurement, and interchangeable probes for different medical functions. This segmentation allows each section to be optimized for its specific function while maintaining overall small diameter.
Solution Approach 2:
The catheter system incorporates interchangeable probes that can perform multiple functions including vision, biopsy, ablation, and navigation. The catheter shaft is designed with universal features (steerable segment, sensor system, lumen structure) that work with all probe types, allowing one catheter to replace multiple specialized devices.
2Length of moving object
If only fiber shape sensors are used to measure the pose of the distal tip, then the catheter diameter can be minimized, but measurement accuracy deteriorates due to inaccuracies in long fiber shape sensors
Solution Approach 1:
The system merges two types of sensors: electromagnetic sensors in the proximal section and fiber shape sensors in the distal section. The electromagnetic sensors provide accurate base point measurement while the fiber shape sensors measure the shape of the distal section. This combination achieves both small diameter and high measurement accuracy.
Solution Approach 2:
The fiber shape sensor acts as an intermediary that bridges the gap between the electromagnetic sensor base point and the distal tip. It measures the shape of the distal section extending from the base point, allowing the system to achieve accurate pose measurement without requiring the electromagnetic sensors to be positioned at the distal tip.
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 navigation and precise positioning of the catheter tip within small lumens while maintaining a compact diameter, allowing for the integration of necessary features like steering, sensing, and imaging, enhancing the catheter's ability to perform medical procedures in tight spaces.
Implementation Method 1
The first sensor system is in the first section and configured for measurement of a pose of the first section
Implementation Method 2
a shape sensor system including both electromagnetic and fiber sensors
Implementation Method 3
An electric signal induced in a coil positioned at a location along the flexible structure of the medical instrument can then be analyzed as part of the pose measure
Data Source
AI summary
A medical system may comprise a catheter that includes an elongate body and a main lumen extending longitudinally through the elongate body. The medical system may also comprise a vision probe that includes a tube extendable through the main lumen of the catheter and comprising a flexible body having an outermost wall and an innermost wall, the innermost wall defining a central lumen. The flexible body contains a plurality of channels formed within the flexible body of the tube and separated from the central lumen by the innermost wall. The plurality of channels includes oblong channels for irrigation and suction and auxiliary channels. The oblong channels have concentric arc shaped surfaces forming an arcuate channel cross-section. The auxiliary channels have a different shape than the one or more oblong channels. The vision probe also includes an imaging system and illumination fibers running through respective auxiliary channels in the tube.