Morphed Fluence Maps for Faster Radiation Plan Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing radiation treatment plans face challenges in accurately discriminating between target volumes and adjacent tissues, leading to increased computational loading and reduced accuracy due to simplified dose calculation methods.
Innovation Solution
The use of morphed fluence maps generated through morphing techniques between calculated fluence maps, allowing for optimized radiation treatment plans with reduced computational time and increased accuracy by predicting fluence maps for beam directions without explicit dose calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a dense set of radiation beam directions is used for dose calculations, then treatment plan accuracy is improved, but computational loading and time frames increase
Solution Approach 1:
The patent creates a lookup table of pre-calculated fluence maps for various beam directions and patient geometries. During optimization, these pre-computed fluence maps are retrieved and interpolated rather than performing full dose calculations for each beam direction, effectively copying previously computed results to avoid redundant computational work while maintaining accuracy.
Solution Approach 2:
The patent performs dose calculations and fluence map generation in advance for a comprehensive set of beam directions and patient geometries before the actual optimization process. These pre-computed results are stored in lookup tables and then rapidly queried during optimization, eliminating the need for time-consuming real-time calculations while ensuring accurate treatment planning.
2Loss of time
If simplified internal dose calculators are used to reduce computational loading, then time requirements are reduced, but accuracy deteriorates
Solution Approach 1:
Instead of using simplified approximations, the patent copies pre-computed fluence maps from lookup tables that were generated using accurate dose calculation methods. These copied fluence maps maintain the accuracy of full dose calculations while enabling rapid retrieval during optimization, avoiding the trade-off between speed and accuracy that plagues simplified calculators.
Solution Approach 2:
The patent introduces fluence maps as an intermediary representation that bridges accurate dose calculations and rapid optimization. Rather than directly calculating doses for every beam direction during optimization (which is slow) or using simple approximations (which are inaccurate), the fluence maps serve as pre-computed intermediaries that can be quickly interpolated to provide both accuracy and speed.
3Reliability
If numerous dose calculations are performed from a dense set of beam directions, then treatment plan quality is improved, but device complexity and computational resources increase
Solution Approach 1:
The patent segments the complex optimization problem into two stages: first, pre-calculating and storing fluence maps for discrete beam directions and patient geometries in lookup tables; second, interpolating between these pre-computed segments during optimization. This segmentation reduces the computational complexity of the optimization process while maintaining treatment plan quality by using the pre-computed segments as building blocks.
Solution Approach 2:
The patent copies pre-computed fluence maps from lookup tables during the optimization process rather than performing new dose calculations for each beam direction. This copying approach significantly reduces computational resource requirements and device complexity while preserving treatment plan quality, as the copied fluence maps are derived from accurate pre-computed data.
Data Source
AI summary
A control circuit calculates at least a first and a second fluence map corresponding to a given patient and then provides at least a third fluence map by morphing between the first and the second fluence map. Radiation treatment plan optimization can proceed as a function, at least in part, of those fluence maps. These teachings will accommodate initially subdividing a treatment arc corresponding to the radiation treatment plan into a plurality of dose calculation sectors. In such a case, the foregoing calculations can include calculating the first fluence map for a first one of the dose calculation sectors and calculating the second fluence map for a second one of the dose calculation sectors. By one approach, the first dose calculation sector does not overlap with the second dose calculation sector. By one approach, the first and second dose calculation sectors are adjacent to one another.