Dynamic MLC Tracking With EPID Signal Acquisition Regions
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Solution Overview
Problem
Existing radiation therapy systems face challenges in accurately tracking the movement precision of multileaf collimators (MLCs) during dynamic conformal radiation therapy, particularly in stereotactic radiosurgery and stereotactic body radiation therapy, which affects the efficacy of treatment.
Innovation Solution
A system and method for dynamic MLC tracking using an electronic portal imaging device (EPID) to identify working leaves and determine a signal acquisition region based on planned position trajectories, with a sampling rate adjusted according to the planned speed profiles, to improve measurement accuracy and reduce motion blur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the EPID captures images at a high sampling rate to track fast-moving MLC leaves, then the measurement precision of leaf position is improved, but the amount of imaging data and processing time increase
Solution Approach 1:
The patent applies local quality by determining a signal acquisition region (SAR) that covers only the specific area where MLC leaves are moving, rather than capturing the entire imaging plane. This localized approach reduces the amount of data acquired while maintaining measurement precision in the critical region where leaf positions need to be tracked.
Solution Approach 2:
The patent segments the imaging process by dividing the full imaging plane into multiple regions, identifying and acquiring data only from the signal acquisition region where MLC leaves are located. This segmentation allows the system to reduce overall data volume while preserving measurement quality in the relevant area.
2Manufacturing precision
If the EPID captures images at a high sampling rate to reduce motion blur, then the manufacturing precision of leaf position tracking is improved, but the processing time and data volume increase
Solution Approach 1:
By focusing the EPID acquisition on a localized signal acquisition region rather than the entire imaging plane, the patent reduces the processing time required while maintaining tracking precision. The reduced data volume from localized acquisition allows for faster processing without sacrificing measurement accuracy in the critical leaf position regions.
3Area of stationary object
If the EPID acquires data from the entire imaging plane, then complete coverage is ensured, but the measurement precision of MLC leaf position is reduced due to increased data volume and processing complexity
Solution Approach 1:
The patent extracts only the necessary signal acquisition region from the full imaging plane, identifying and acquiring data solely from the area where MLC leaves are positioned. This extraction eliminates redundant data from regions without leaves, reducing overall data volume and processing complexity while maintaining complete coverage of the relevant leaf positions.
Data Source
AI summary
The present disclosure provides systems and methods for dynamic multileaf collimator (MLC) tracking. A method may include identifying a plurality of working leaves of the MLC at a control point; determining, for the control point, a signal acquisition region of an electronic portal imaging device (EPID) based on a plurality of planned position trajectories of the plurality of working leaves, wherein the signal acquisition region is part of an imaging plane of the EPID and includes a plurality of acquisition rows; and obtaining an image from the EPID at the control point, wherein the image includes information acquired in the signal acquisition region.