Radiation Therapy Dose Uncertainty Quantification via Geometric Error Modeling
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Solution Overview
Problem
Current radiation therapy systems face challenges in accurately reporting delivered dose for specific treatment fractions and accumulated dose for multiple fractions due to geometric errors introduced by deformable image registration, which leads to uncertainty in dose distribution.
Innovation Solution
The system determines and presents the uncertainty in the accumulated dose for specific regions of interest by quantitatively analyzing geometric errors associated with deformable image registration, allowing for the presentation of best-case, worst-case, and most-likely dosing scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If deformable image registration is used to account for anatomical changes during treatment, then adaptability to patient anatomy changes is improved, but measurement precision of dose distribution deteriorates due to geometric errors
Solution Approach 1:
The system implements feedback by using day-of-treatment imaging to detect anatomical changes and then adjusting the treatment plan accordingly. The deformable image registration process provides feedback on geometric deviations, which are then used to correct dose calculations and account for anatomical variations between the planning stage and treatment delivery.
Solution Approach 2:
The system performs preliminary deformable image registration and geometric error modeling before final dose calculation. By pre-characterizing the geometric errors through registration of treatment fraction images to the planning image, the system prepares correction factors in advance that are then applied to accurately calculate the accumulated dose distribution.
2Loss of information
If deformable image registration is performed to map dose between images, then information completeness about dose distribution is improved, but reliability of dose measurement deteriorates due to geometric errors
Solution Approach 1:
The system introduces a geometric error model as an intermediary between the deformable image registration process and the final dose calculation. This intermediary component characterizes and quantifies the geometric errors introduced by registration, allowing the system to compensate for these errors and maintain reliable dose measurements while still achieving complete dose distribution information.
Data Source
AI summary
A computer-implemented method of generating dose information for a region of patient anatomy includes determining a first set of dose values for a first three-dimensional (3D) image of the region, wherein each value in the first set of dose values is associated with a different voxel of the first 3D image, and wherein the first 3D image is associated with a specific application of dose to the region; determining a second set of dose values for a representative 3D image of the region, wherein each value in the second set of dose values is associated with a different voxel of the representative 3D image; determining a set of geometric error models for the representative 3D image of the region, wherein each geometric error model in the set of geometric error models indicates a geometric error between a voxel of the representative 3D image and one or more voxels of a treatment fraction 3D image of the region; and based on the second set of dose values and the set of geometric error models, determining a set of dose probability values for each voxel of the representative 3D image, wherein each set of dose probability values includes at least one dose value and a probability value that corresponds to the dose value.