Medical Tool Orientation Tracking Using Surface Shadow Geometry
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Solution Overview
Problem
Current interventional tool tracking systems rely solely on tracking the tip of the tool after insertion, leading to inaccurate trajectory planning and multiple skin entries, causing discomfort and slower recovery due to the lack of 3D information and physical limitations in tools like ablation catheters.
Innovation Solution
A method for determining the orientation of a tool by obtaining image data of the tool and its shadow on a surface, segmenting the tool and shadow representations, and calculating the elevation angle and orientation using a light source positioned relative to the image sensor, allowing for accurate pre-insertion tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only the tip of the tool is tracked after insertion, then the tracking system remains simple, but the trajectory planning accuracy deteriorates and multiple skin entries are required
Solution Approach 1:
The system performs preliminary tracking of the tool orientation and trajectory planning on the skin surface before insertion, using shadow-based detection to determine the tool's elevation angle and orientation. This preliminary action allows accurate trajectory planning to be completed before the tool enters the body, eliminating the need for post-insertion tip tracking and multiple skin entries.
Solution Approach 2:
The patent introduces a shadow as an intermediary element to indirectly measure the tool's orientation and position. By detecting the shadow cast by the tool on the skin surface and analyzing its geometric relationship with the tool, the system can determine the tool's elevation angle and orientation without directly tracking the tool tip after insertion, thus improving measurement precision while maintaining system simplicity.
2Measurement precision
If 3D information is not visible during trajectory planning, then the planning process is simpler, but the accuracy of needle trajectory prediction deteriorates
Solution Approach 1:
The patent uses shadow-based detection to infer three-dimensional tool orientation (elevation angle and orientation) from two-dimensional shadow measurements on the skin surface. By analyzing the geometric relationship between the tool, its shadow, and the light source, the system recovers 3D spatial information that would otherwise be lost, enabling accurate trajectory prediction without direct 3D visualization.
3Reliability
If multiple skin entries are performed to identify correct tool trajectory, then the probability of achieving correct trajectory increases, but subject discomfort and recovery time increase
Solution Approach 1:
The system performs preliminary measurement and verification of tool orientation and trajectory on the skin surface using shadow-based detection before insertion. This allows the clinician to confirm the correctness of the planned trajectory in advance, ensuring high reliability of the first attempted insertion and eliminating the need for multiple skin entries that cause discomfort and delay recovery.
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
Improves the accuracy of tool orientation determination by considering the tool's entire length, reducing the need for multiple skin entries and enhancing recovery by providing real-time, precise trajectory planning.
Implementation Method 1
a tool shadow on the surface, the tool shadow resulting from light incident on the tool generated by way of at least one light source
Data Source
AI summary
The invention provides a method for determining an orientation of a tool for performing a medical intervention on a subject. The method includes obtaining image data for an image of a surface of, or over, a subject, a tool adjacent the surface and a tool shadow on the surface, the tool shadow resulting from light incident on the tool generated by way of at least one light source positioned at a predetermined position relative to the image sensor. A representation of the surface is obtained and representations of the tool and the tool shadow are segmented from the image data and used to determine an elevation angle of the tool. The orientation of the tool is determined based on the segmented representation of the tool, the segmented representation of the tool shadow and the elevation angle.