Medical Instrument Tracking via Marker Offset Calibration
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Solution Overview
Problem
Current medical instrument tracking systems are limited in their ability to accurately track a wide range of medical instruments, especially those with elongated shapes, as they often require pre-stored geometric information and are not effective when the instrument tip is inside a subject.
Innovation Solution
A system that uses an instrument marker, such as biocompatible reflective or fluorescent paint, attached to the medical instrument, along with a processing unit to detect line segments and determine the offset of the instrument tip from a reference marker, allowing for tracking without pre-stored database information and even when the tip is inside a subject.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pre-stored geometric information in a database is used for tracking, then tracking accuracy for known instruments is improved, but the system cannot track unknown or new medical instruments
Solution Approach 1:
The patent extracts the identification features (marker position, line segment characteristics) from the instrument and uses only these essential features for tracking, rather than storing complete geometric information. This allows tracking of any instrument with the required marker without maintaining a comprehensive database of all possible instrument geometries.
Solution Approach 2:
Instead of storing complete instrument models in a database, the system creates a simplified representation by detecting the marker position and line segment in images. This copied information (marker location relative to tip) is sufficient for tracking purposes and eliminates the need for extensive database storage.
2Reliability
If the instrument tip is inside a subject, then the tip position cannot be directly observed in tracking images, but tracking continuity is maintained through offset calculation
Solution Approach 1:
The system performs preliminary calibration by detecting the offset between the marker and tip position when the tip is visible and accessible. This pre-determined offset is then used to calculate tip position during procedures when the tip is inside the subject and cannot be directly observed, maintaining tracking reliability without continuous visual confirmation.
Solution Approach 2:
The marker serves as an intermediary element that remains visible and trackable even when the tip is inside the subject. By tracking the marker's position and applying the pre-determined offset, the system indirectly determines tip position without requiring direct observation of the tip itself.
3Ease of operation
If a marker is placed on the instrument shaft away from the tip, then the marker remains visible and trackable, but the tip position must be calculated with offset
Solution Approach 1:
The offset between marker and tip position is determined in advance during calibration when both are accessible. This pre-measured offset compensates for the distance between the visible marker and the actual tip, maintaining measurement precision despite the marker's remote placement on the instrument shaft.
Data Source
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AI summary
The present invention relates to medical instrument tracking. In order to facilitate tracking a medical instrument, a system (100) is provided for tracking a medical instrument. The system comprises an instrument marker (14), a tracking arrangement (16), and a processing unit (18). The instrument marker is attached to the medical instrument on a marker position (20). The tracking system is configured to detect line segments (22) in the 5 field of interest and to detect the attached instrument marker. The processing unit is configured to identify a line segment (24) on which the attached instrument marker is detected as the medical instrument, and to determine an offset (26) between a position of a medical instrument tip (28) and the marker (14) by touching a reference marker (34) on the subject with the medical instrument (10).