Respiratory Motion Tracking With Predicted KV Image Timing
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Solution Overview
Problem
Existing radiotherapy techniques face challenges in accurately tracking tumor movement during treatment due to patient motion, leading to reduced treatment effectiveness and potential damage to healthy tissue, with existing tracking methods like 4DCT introducing inaccuracies and KV imaging increasing patient dose.
Innovation Solution
A method and device for tracking patient body regions using motion estimation techniques to predict optimal times for KV image acquisition, reducing the number of images taken and minimizing patient radiation dose while maintaining accurate tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If KV images are taken frequently to track tumor movement accurately, then tracking precision is improved, but patient radiation dose increases
Solution Approach 1:
The system performs preliminary motion analysis using surrogate signals (chest surface movement, respiratory signals) to predict future tumor positions. By anticipating tumor motion based on correlated respiratory patterns, the system schedules KV images at optimal moments without requiring continuous imaging, thereby maintaining tracking precision while reducing radiation exposure.
Solution Approach 2:
The patent introduces surrogate signals as intermediaries between respiratory motion and tumor position. These surrogates (chest surface markers, respiratory flow signals) serve as mediators that correlate with internal tumor movement, allowing the system to infer tumor position without direct continuous imaging, thus reducing the number of KV images needed.
2Measurement precision
If 4DCT imaging is used to track tumor position, then tracking accuracy is improved, but acquisition time increases and introduces motion averaging inaccuracies
Solution Approach 1:
The system extracts only the essential motion information needed for tracking by using surrogate signals and motion vectors rather than acquiring complete 4DCT datasets. By taking out only the relevant temporal-spatial motion parameters from the breathing cycle, the system achieves tracking accuracy without the time penalty and motion averaging effects of full 4DCT acquisition.
Solution Approach 2:
Instead of performing complete 4DCT reconstruction which averages motion over the entire acquisition period, the system applies partial action by using selective motion estimation from surrogate signals and targeted KV images at specific phases. This partial approach avoids the excessive time requirement while maintaining sufficient accuracy for real-time tracking.
3Reliability
If respiratory gating is used to control radiation application, then safety is improved, but treatment time increases due to assumptions about tumor-surface correlation
Solution Approach 1:
The system implements feedback by continuously monitoring surrogate respiratory signals and using motion estimation algorithms to update predicted tumor positions in real-time. This feedback loop allows the system to adapt to actual patient breathing patterns without relying on fixed assumptions, enabling safer gating decisions that reduce unnecessary treatment interruptions and shorten overall treatment time.
Data Source
AI summary
Disclosed herein is a medical device for tracking movement of a region of a patient's body. The region has a range of motion, for example a range of respiratory motion. The device comprises a controller configured to determine a motion of the region based on one or more initial images depicting at least part of the region. The controller is further configured to predict, based on the determined motion, a motion event time at which at least one property associated with the motion or position of the region will meet at least one criterion, wherein the at least one criterion comprises the region being located at a particular point in its range of motion. The controller is further configured to determine, based on the predicted motion event time, at least one subsequent image capture time at which at least one subsequent image should be captured.