VMAT Non-Coplanar Trajectory Planning
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Solution Overview
Problem
Current radiotherapy planning systems have limited support for optimizing non-coplanar beam directions due to the combinatorial nature of the problem, making existing approaches like simulated annealing or integer programming too computationally expensive for practical use, especially in Volumetric Modulated Arc Therapy (VMAT) which is restricted to coplanar beams.
Innovation Solution
A method and system that determine candidate beam directions, select non-coplanar beam directions using a fluence optimization algorithm, and optimize delivery options to generate VMAT treatment plans with non-coplanar trajectories, involving both beam rotation and subject support rotation, using a computationally efficient iterative approach to adapt coplanar arc therapy planning algorithms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-coplanar beam directions are optimized using simulated annealing or integer programming, then organ sparing is improved, but computational cost becomes too expensive for practical use
Solution Approach 1:
The optimization process is divided into distinct segments: first determining candidate beam directions, then selecting a subset of non-coplanar directions, and finally optimizing delivery options. This segmentation breaks the computationally expensive combinatorial problem into manageable stages that can be solved efficiently in practice.
Solution Approach 2:
Candidate beam directions are determined in advance before the actual optimization process. This preliminary action reduces the search space for subsequent optimization steps, making the overall process computationally feasible while still achieving improved organ sparing through non-coplanar configurations.
2Device complexity
If VMAT delivery is restricted to coplanar beams, then delivery complexity is reduced, but treatment effectiveness for organ sparing is limited
Solution Approach 1:
The system transitions from static coplanar beam configurations to dynamic non-coplanar trajectories that involve both gantry rotation and couch rotation. This dynamic approach allows the beam to access targets from multiple angles in three-dimensional space, improving organ sparing while maintaining deliverability through coordinated motion.
Solution Approach 2:
The invention adds the couch rotation dimension to the traditional gantry rotation, transforming the system from two-dimensional coplanar delivery to three-dimensional non-coplanar delivery. This dimensional expansion enables superior dose distribution and organ sparing without prohibitively increasing delivery complexity.
3Manufacturing precision
If non-coplanar trajectories are implemented in VMAT, then treatment plan quality is improved, but computational complexity increases
Solution Approach 1:
The treatment planning process is segmented into distinct optimization stages: candidate beam direction determination, subset selection, and delivery option optimization. Each stage handles a specific aspect of the problem, reducing overall computational complexity while maintaining high treatment plan quality through non-coplanar trajectories.
Solution Approach 2:
The system introduces intermediate structures such as candidate beam directions and delivery options that mediate between the raw optimization problem and the final treatment plan. These intermediaries simplify the computational task at each stage while preserving the ability to generate high-quality non-coplanar treatment plans.
Data Source
AI summary
A method includes determining a set of candidate beam directions. The radiation therapy method further includes selecting a sub-set of non-coplanar beam directions of interest from the set of candidate beam directions based on a fluence optimization using a beam angle selection algorithm. The radiation therapy method further includes determining a set of delivery options based on a beam trajectory algorithm, wherein the delivery options at least include a non-coplanar trajectory during radiation treatment delivery. The radiation therapy method further includes optimizing the delivery options to generate a VMAT radiation plan with non-coplanar beam trajectories. The optimizing of the delivery options includes optimizing at least one machine parameter.