C-arm Tracking System Using Joint Sensors and Kinematic Chain
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Solution Overview
Problem
There is a need for practical and cost-effective ways to accurately track the positions of imaging devices like C-arm x-ray fluoroscopy machines, as existing optical localizers are costly and constrained by the requirement of an unobstructed line of sight, limiting their use in operating rooms and being inefficient in reducing x-ray exposure for medical personnel.
Innovation Solution
The implementation of a tracking system using sensors to monitor the positions of individual joints of the C-arm, treating the imaging machine as a kinematic chain, and calibrating the system using phantoms to account for non-rigid structures and gravitational deformations, allowing for accurate tracking without the need for a highly accurate localizer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical localizers with cameras are used to track C-arm positions, then tracking functionality is provided, but the cost increases significantly and operating room space is constrained due to unobstructed line of sight requirements
Solution Approach 1:
The patent replaces the optical camera-based tracking system with a mechanical sensor system that attaches directly to the C-arm joints. Sensors monitor joint positions and orientations mechanically, eliminating the need for optical cameras and targets, thereby reducing cost while maintaining tracking accuracy.
Solution Approach 2:
The patent extracts the tracking functionality from the optical environment and embeds it directly into the C-arm structure through integrated sensors. This removes the external optical cameras and targets from the operating room, eliminating line of sight constraints and reducing space requirements.
2Measurement precision
If optical localizers are used for tracking, then position monitoring is achieved, but operating room space is limited and positioning of other equipment and personnel is constrained
Solution Approach 1:
The patent nests the tracking sensors directly within the C-arm joint structures. The sensors are integrated into the existing mechanical components of the C-arm, allowing tracking functionality to be embedded within the imaging device itself without occupying additional operating room space.
3Measurement precision
If traditional tracking systems are used, then spatial position tracking is provided, but x-ray exposure time for medical personnel is not sufficiently reduced
Solution Approach 1:
The patent implements real-time feedback by continuously monitoring C-arm joint positions and orientations through the sensor system. This real-time spatial information is fed back to the control system, enabling dynamic adjustment of imaging parameters and procedures to minimize x-ray exposure time while maintaining image quality.
Data Source
AI summary
An imaging system such as a medical C-arm x-ray fluoroscopy machine includes a tracking system that tracks a position of an x-ray source and an x-ray detector using sensors which monitor positions of joints which allow relative motions of segments in a support for the x-ray source and detector. Sensor readings are used in a kinematic chain. One or more segments that behave in a non-rigid manner are replaced by a virtual rigid link in the kinematic chain that takes into account deformations of the segments (e.g. under the influence of gravity). Calibration methods permit calibration of the system using images of phantoms.