Tracking Rigid Object Parts Without Reference Points
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Solution Overview
Problem
Conventional medical navigation systems struggle to effectively track and reposition small, rigid object parts or bone structures that are difficult or impossible to register, especially when detached from a reference object, without detected reference points.
Innovation Solution
An image-assisted navigation system is used to track and reposition rigid object parts by creating a patient data set, marking the object part, and employing reference stars to determine its position relative to a global coordinate system, allowing for precise placement and movement tracking without physical contact detection of reference points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional medical navigation systems are used to track rigid object parts, then reference points can be detected, but small rigid object parts that are difficult or impossible to register cannot be tracked
Solution Approach 1:
The patent introduces a reference object with reference points as an intermediary between the navigation system and the small rigid object part. The reference object serves as a mediator that can be easily detected by the navigation system, while its spatial relationship to the small object part allows indirect tracking of the otherwise undetectable object part
Solution Approach 2:
The patent creates a digital model (copy) of the small rigid object part in the patient data set. By tracking the reference object and using the known spatial relationship, the system virtually copies the position and orientation of the small object part in the digital model, enabling tracking without directly detecting the small object part itself
2Measurement precision
If reference points are required for tracking, then position can be ascertained, but detached or removed object parts cannot be tracked
Solution Approach 1:
The reference object acts as an intermediary carrier that maintains a known spatial relationship to the detachable object part. When the object part is detached, the reference object remains attached to the patient's anatomy and continues to serve as the detection intermediary, allowing the system to track the object part's position even when physically separated
Solution Approach 2:
The patent establishes the spatial relationship between the reference object and the object part in advance, before detachment occurs. This preliminary configuration of coordinates and transformations enables the system to calculate the object part's position based on reference object tracking, even after the object part is removed from its original location
3Measurement precision
If physical contact detection is used for reference points, then accurate registration is achieved, but small rigid object parts cannot be registered
Solution Approach 1:
The reference object with its larger, more accessible reference points serves as an intermediary that can be easily and accurately detected by the navigation system. This mediator approach allows accurate registration to be achieved indirectly, without requiring direct physical contact detection on the small object part itself
Solution Approach 2:
The system creates a virtual representation of the small object part in the digital patient model. By detecting the reference object and copying the spatial transformation to the virtual model of the small object part, accurate registration is achieved without requiring physical contact with the small object part
Data Source
AI summary
A method for tracking at least one rigid object part of a rigid reference object, wherein the rigid object part can be detached or removed from the rigid reference object is provided. The method includes obtaining a patient data set of a region around the object part, attaching a first reference star in a fixed position relative to the object part situated on the reference object, detecting reference points on the reference object and ascertaining three-dimensional spatial positions of the reference points of the reference object, assigning the three-dimensional spatial positions of the reference points of the reference object to corresponding points in the patient data set, attaching a second reference star to the object part, ascertaining positional information of the second reference star; and ascertaining positional information of the object part or tracking the object part based on the positional information of the second reference star.