Automated Tumor Motion Estimation in Radiotherapy
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Solution Overview
Problem
Current radiotherapy methods inadequately account for tumor motion during treatment, leading to excessive exposure of healthy tissue to radiation due to the time-intensive and non-reproducible manual outlining of tumor motion in two-dimensional slices.
Innovation Solution
A method and apparatus that automate tumor motion estimation through periodic updating of radiation therapy plans using deformable image registration and automated segmentation, allowing for precise adaptation to the current size and location of the tumor during fractionated treatments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual outlining on two-dimensional slices is used to delineate tumor motion, then tumor motion can be estimated, but the process is too time intensive and lacks reproducibility
Solution Approach 1:
The patent replaces manual mechanical outlining with an automated computer-based system that uses image registration algorithms to track tumor motion across multiple phases of the respiratory cycle. The system automatically identifies tumor position in 4D images and generates motion trajectories without manual intervention, eliminating the time-intensive manual process while maintaining or improving measurement precision through consistent algorithmic application.
Solution Approach 2:
The patent creates a virtual model of tumor motion by copying and tracking tumor position across multiple respiratory phases captured in 4D imaging. Instead of manually measuring motion in each slice, the system copies the tumor contour from reference images and transforms it according to registered anatomical landmarks, generating accurate motion estimates automatically through digital replication rather than manual measurement.
2Reliability
If manual outlining is used for tumor delineation, then tumor motion can be accounted for, but the process lacks reproducibility
Solution Approach 1:
The patent replaces variable manual delineation processes with a standardized automated algorithm that applies consistent image registration and contour transformation methods across all cases. This substitution eliminates operator-dependent variability and improves reproducibility, as the same algorithmic rules are applied uniformly regardless of which operator performs the analysis.
Solution Approach 2:
The patent transforms the delineation process from a manual artistic interpretation task into a parameter-driven computational process. By changing the approach from subjective manual tracing to objective algorithmic contour generation based on registered anatomical parameters, the system achieves improved reproducibility while managing complexity through standardized parameter transformations.
3Manufacturing precision
If PTV includes margin to account for motion error, then radiation can be applied to diseased tissue, but healthy tissue is exposed to radiation
Solution Approach 1:
The patent implements dynamic adaptation of the PTV by incorporating real or simulated tumor motion trajectories into the treatment plan. Instead of using a static fixed margin, the system dynamically adjusts the PTV boundaries to follow the actual or predicted tumor position throughout the respiratory cycle, maintaining precise coverage of the moving target while reducing unnecessary exposure of surrounding healthy tissues.
Solution Approach 2:
The patent performs preliminary characterization of tumor motion through 4D imaging and registration analysis before finalizing the treatment plan. By预先 determining the tumor's motion pattern and range, the system can pre-adjust the PTV and radiation delivery parameters to account for expected motion, ensuring accurate tumor coverage while minimizing healthy tissue exposure without needing larger safety margins.
Data Source
AI summary
A method and apparatus accounting for tumor motion during radiation therapy is provided. The method allows for radiation therapy treatments based on updated radiation therapy plans. For each fractionate radiation treatment that results in an updated radiation treatment, radiation treatment images are acquired, automatically segmented, and then subject to deformable registration to develop updated contours and an updated radiation therapy plan.