VMAT Dose-Calculation Sectors for Organ-at-Risk Discrimination
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Solution Overview
Problem
Existing radiation treatment plans, particularly volumetric modulated arc therapy (VMAT), face challenges in optimizing treatment parameters due to a huge search space and non-convex problems, leading to locally optimal but inferior solutions, and fail to effectively discriminate between target volumes and adjacent tissues.
Innovation Solution
The approach involves defining non-uniform dose-calculation sectors that contain organs-at-risk and optimizing radiation treatment plans based on these sectors, using a control circuit to manage treatment parameters and gantry movements, allowing for right-sized and complexity-based sector definitions to enhance optimization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct optimization of control points is attempted in VMAT, then treatment plan optimization is pursued, but the huge search space makes the process unfeasible in practice
Solution Approach 1:
The patent segments the continuous VMAT control point optimization problem into discrete angular bins or sectors. By dividing the gantry rotation range into discrete segments and assigning uniform dose rates within each sector, the patent transforms the continuous optimization problem into a discrete one with manageable complexity, making the optimization process computationally feasible while still achieving effective treatment plan optimization.
2Reliability
If optimization explores more of the search space to avoid local optima, then better treatment plans may be found, but the optimization process becomes significantly more complex and computationally intensive
Solution Approach 1:
The patent changes the parameterization of the optimization problem by introducing discrete angular bins and uniform dose rate assumptions within sectors. This parameter transformation simplifies the search space structure, allowing more thorough exploration of viable solutions without requiring exponentially more computational resources. The discretization enables systematic exploration while maintaining optimization quality.
3Device complexity
If uniform dose rates are assumed across gantry angles, then optimization complexity is reduced, but discrimination between target volumes and adjacent tissues deteriorates
Solution Approach 1:
The patent segments the gantry rotation into discrete angular bins where uniform dose rates are assumed within each bin, but different bins can have different dose rates. This segmentation allows the system to maintain low computational complexity within each sector while achieving good dose discrimination across different angular regions by varying the dose rates assigned to different bins, thus resolving the contradiction between simplicity and precision.
Data Source
AI summary
A control circuit accesses information regarding a given patient. That information may include, for example, segmentation information that depicts at least one treatment volume and at least one organ-at-risk. The control circuit then defines a plurality of dose-calculation sectors for the given patient as a function, at least in part, of the information regarding the given patient. Those dose-calculation sectors are not assumed to be uniformly sized. These teachings can then provide for optimizing a radiation treatment plan, such as a volumetric modulated arc therapy radiation treatment plan, as a function, at least in part, of the plurality of dose-calculation sectors to provide an optimized radiation treatment plan.