Direct Target Registration for Radiation Tracking
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Solution Overview
Problem
Conventional image-guided radiation treatment systems face challenges in accurately tracking small, poorly differentiated tumors within large organs, especially when these tumors are in motion due to patient breathing, as they require invasive fiducial markers and are computationally expensive, leading to slow imaging processing and inaccurate tumor tracking.
Innovation Solution
The method involves direct registration of digitally reconstructed radiographs (DRRs) to detect and track moving targets by generating 2D contours of the target in DRRs, creating regions of interest, and matching them with in-treatment x-ray images using a search algorithm to maximize similarity measures, reducing computational tasks and increasing processing speed for accurate target detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional image-guided systems use 2D-2D registration of in-treatment x-ray images with DRRs, then target detection can be performed, but computational cost is high and processing speed is slow
Solution Approach 1:
The patent segments the DRR into multiple candidate regions (ROIs) that are likely to contain the target, rather than performing registration across the entire image. This segmentation reduces the computational domain and allows faster processing while maintaining detection accuracy through focused comparison of relevant regions only.
Solution Approach 2:
The patent performs preliminary actions by pre-identifying and segmenting candidate target regions in the DRR before the actual registration process. By preparing these ROIs in advance with expected target locations and characteristics, the system reduces the computational burden during real-time processing and speeds up target detection.
2Measurement precision
If fiducial markers are used to track moving tumors, then target tracking accuracy is improved, but the procedure becomes invasive
Solution Approach 1:
The patent uses digitally reconstructed radiographs (DRRs) as synthetic copies of what the in-treatment x-ray images should look like based on pre-treatment 3D imaging data. By comparing actual images with these synthetic copies, the system achieves accurate target tracking without requiring physical fiducial markers, thus avoiding invasive procedures.
Solution Approach 2:
The patent replaces the mechanical approach of inserting fiducial markers into the patient with a computational approach using image registration. The system substitutes physical marker-based tracking with algorithm-based comparison of anatomical structures in x-ray images and DRRs, eliminating the need for invasive marker placement.
3Ease of operation
If small tumors are tracked without fiducial markers, then the procedure remains non-invasive, but target detection accuracy decreases
Solution Approach 1:
The patent applies local quality by focusing computational resources on specific regions of interest rather than treating the entire image uniformly. By identifying and analyzing only the candidate regions where small tumors are likely to be located, the system maintains high detection accuracy for small targets while keeping the overall procedure non-invasive and computationally efficient.
Solution Approach 2:
The patent enhances target detection capability by utilizing the third dimension through 3D-to-2D projection. The system generates DRRs from 3D pre-treatment imaging data and compares them with 2D in-treatment x-ray images, leveraging the additional dimensional information to improve detection of small tumors that would be difficult to identify in 2D images alone.
Data Source
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AI summary
Systems, methods and apparatus for directly tracking radiation targets during image-guided radiation treatment using 2D contouring and adaptive windowing.