Target Motion Simulator for Radiation Therapy Tracking
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Solution Overview
Problem
Current radiosurgery and radiation therapy systems face challenges in accurately compensating for cardiac motion, which is faster than respiratory motion, leading to potential errors in dose delivery due to the inability to track and compensate for the differential motion between fiducials and treatment areas, especially in areas where fiducial placement is difficult or impractical.
Innovation Solution
A target motion simulator system that simulates both respiratory and cardiac motions using actuators synchronized with physiological signals, such as EKG, to accurately track and compensate for the motion of radiation therapy devices, allowing for precise alignment and dose delivery to moving targets like the heart and adjacent tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single fiducial is used for tracking, then the system is simple to operate, but tracking accuracy deteriorates due to differential motion between fiducial and target
Solution Approach 1:
The patent divides the tracking system into multiple independent fiducials placed at different locations (e.g., on the heart surface and on surrounding tissues). Each fiducial tracks local motion independently, allowing the system to capture differential motion patterns across the treatment area. This segmentation enables accurate reconstruction of target position even when fiducials experience different motion patterns than the target itself.
2Measurement precision
If fiducials are placed on the target area, then tracking precision is improved, but device complexity increases due to difficulty of fiducial placement
Solution Approach 1:
The patent introduces intermediary fiducials placed on accessible surrounding tissues (such as skin or subcutaneous tissue near the target) that serve as proxies for tracking the target motion. These intermediary fiducials are easier to place than direct target fiducials, and their motion is correlated with target motion through pre-established geometric relationships or motion modeling, thus maintaining tracking precision while reducing placement complexity.
3Manufacturing precision
If motion compensation is applied, then dose delivery accuracy is improved, but device complexity increases due to additional tracking components
Solution Approach 1:
The patent implements a dynamic tracking system that continuously monitors fiducial positions and updates target position estimates in real-time during radiation delivery. The system adapts to changing motion patterns by processing sequential fiducial measurements and applying motion compensation algorithms dynamically, rather than relying on static pre-treatment positioning. This enables accurate dose delivery despite the added complexity of continuous monitoring and real-time calculation.
Data Source
AI summary
A target motion simulator system for use in verifying target tracking with a radiation therapy device. The system comprises a radiation detection target coupled to a first motion actuator simulating a first motion of a first tissue and a fiducial coupled to a second motion actuator simulating a second motion of a second tissue offset from the first tissue, a component of the first motion being asynchronous with the second motion. A synthetic physiological signal generator is synchronized with the component of the first motion, wherein an output signal from the generator, in combination with a sensed position of the fiducial, may be used by the radiation therapy device in tracking the target.