Real-Time Radiation Therapy Using Partial Image Fluence Updates
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Solution Overview
Problem
Current radiation therapy systems require high-quality, high-SNR images for accurate target centroid calculation, which are not feasible in real-time due to data acquisition time and imaging dose concerns, leading to potential irradiation of non-target regions.
Innovation Solution
The use of partial images with lower SNR, combined with a radiation-firing matrix, to dynamically update fluence maps in real-time, allowing precise radiation delivery to moving targets by adjusting beamlet patterns and intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-quality, high-SNR images are acquired for accurate target centroid calculation, then measurement precision is improved, but acquisition time increases and imaging dose increases
Solution Approach 1:
The patent applies partial action by using only a subset of available imaging data (e.g., a limited number of projection angles or a specific region of interest) rather than acquiring complete high-quality images. This allows the system to obtain sufficient centroid information with reduced acquisition time and lower imaging dose, while still maintaining adequate measurement precision for real-time tracking
Solution Approach 2:
The system dynamically adjusts imaging parameters such as SNR requirements, image resolution, and acquisition frame rate based on treatment phase and target motion characteristics. By changing these parameters adaptively, the system achieves acceptable measurement precision for real-time control without the time and dose penalties of consistently using high-SNR imaging
2Measurement precision
If high-quality, high-SNR images are acquired for accurate target centroid calculation, then measurement precision is improved, but imaging dose increases
Solution Approach 1:
The patent uses partial imaging data (e.g., limited-angle projections or ROI-based imaging) to calculate target centroid position, avoiding the need for complete high-SNR images. This reduces the imaging dose delivered to the patient while maintaining sufficient measurement precision for accurate target tracking and fluence map updates
Solution Approach 2:
The system introduces an image processing intermediary that extracts essential target location information from low-SNR or partial images through techniques such as registration, filtering, or machine learning-based reconstruction. This intermediary enables accurate centroid calculation from reduced-dose images, decoupling measurement precision from imaging dose
3Productivity
If fluence maps are updated in real-time using partial images with lower SNR, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The system implements a feedback loop where fluence maps are continuously updated based on real-time target position measurements from partial images. The updated fluence maps are immediately applied, and the process repeats with subsequent images, creating a closed-loop control system that maintains target accuracy despite using lower-SNR imaging data
Solution Approach 2:
The patent performs preliminary processing of partial images (e.g., noise filtering, registration, or feature extraction) to enhance the effective SNR before centroid calculation. This preliminary action prepares the degraded image data in advance, enabling accurate target location determination that supports real-time fluence map updates without sacrificing measurement precision
Data Source
Figure 1A~1E
Figure 1F~1H
Figure 2A
AI summary
Disclosed herein are systems and methods for guiding the delivery of therapeutic radiation using incomplete or partial images acquired during a treatment session. A partial image does not have enough information to determine the location of a target region due to, for example, poor or low contrast and/or low SNR. The radiation fluence calculation methods described herein do not require knowledge or calculation of the target location, and yet may help to provide real-time image guided radiation therapy using arbitrarily low SNR images.