Tool-Mounted Camera for Deflection Compensation in Needle Guidance
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Solution Overview
Problem
Current optical tracking systems for guiding needles in medical procedures are less accurate due to the use of intermediate reference frames, which can lead to errors in needle deflection and increased risk of complications like Pneumothorax, especially when dealing with semi-flexible tools that bend during insertion.
Innovation Solution
A system and method that directly measures the position of a hand-held tool relative to the body in five or six degrees of freedom using a camera attached to the tool, with a marker arrangement on the body surface to determine the tool's position and compensate for deflection, allowing for precise guidance of the tool's distal end to a target without an external reference frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an intermediate reference frame is used to determine tool position relative to the body, then the measurement system can be implemented, but the accuracy of tool position determination deteriorates due to cumulative errors
Solution Approach 1:
The patent extracts and eliminates the intermediate reference frame from the measurement system. By directly measuring the tool position relative to the body without an external reference frame, the system removes the source of cumulative errors and achieves direct measurement of tool coordinates in body coordinates.
Solution Approach 2:
The patent creates an asymmetric measurement architecture where the measurement origin is directly attached to the tool rather than being external and symmetric to both tool and body. This asymmetric configuration enables direct measurement without coordinate transformation.
2Measurement precision
If location sensors are attached to the proximal part of the needle, then the needle can be tracked, but the location determination of the needle's distal tip becomes erroneous due to needle deflection
Solution Approach 1:
Instead of attaching sensors to the proximal part and calculating distal tip position through coordinate transformations, the patent inverts the approach by directly measuring the distal tip position using a camera mounted on the distal end. This inversion eliminates deflection errors by measuring at the target location rather than inferring from the proximal location.
Solution Approach 2:
The patent introduces a camera as an intermediary measurement device mounted on the distal end of the needle. This camera directly captures the position and orientation of the distal tip, serving as a mediator that provides accurate measurement without being affected by needle deflection in the proximal section.
3Measurement precision
If a camera is mounted on the distal end of the tool, then direct position measurement is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the measurement function with the tool itself by mounting the camera directly on the distal end of the needle. This integration combines the diagnostic tool with the measurement device, eliminating the need for separate tracking systems and reducing overall system complexity despite the added camera component.
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 enhances the accuracy of needle guidance, reduces the risk of complications like Pneumothorax, and provides real-time, precise navigation of semi-flexible tools by directly measuring tool position relative to the body, thereby improving the effectiveness of medical procedures.
Implementation Method 1
a camera for generating images
Implementation Method 2
by monitoring three or more identifiable light sources mounted on the tracked object, calculates the location and orientation of the object in up to six degrees of freedom (6 DOF) through triangulation calculations
Data Source
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Figure 3A~3B
Figure 4A~4B
AI summary
A system for measuring the position of a hand-held tool relative to a body in five or six degrees of freedom is provided. The system comprises a rigid or semi-flexible tool with a distal end for insertion into the body and a proximal portion for manual manipulation outside the body, and a flexible patch carrying a plurality of markers, wherein the patch is configured to be applied or attached to an external surface of the body. The system also comprises a camera for generating images and a mechanical linkage is configured to attach said camera to the proximal portion of said tool such that said camera moves together with said proximal portion of said tool, and said camera is directed with a field of view toward at least part of said distal end of said tool. The field of view includes the markers when the patch is applied or attached to the external surface of the body and the distal end of the tool is inserted into the body. The system further comprises a processing system in data communication with said camera and configured to obtain from the camera images of the external surface of the body including the plurality of said markers, and configured to process the images from said camera to determine a position of at last part of said tool relative to the markers. Furthermore, a method for guiding a distal end of a rigid or semi-flexible tool to a target within a body is provided.