Radiotherapy Fluence Map Optimization Using Anatomy Projections

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Solution Overview

Problem

The process of creating radiation therapy treatment plans is time-consuming and subjective, often requiring trial-and-error adjustments to balance target dose versus organ-at-risk sparing, especially with complex anatomies involving multiple critical organs, leading to uncertainty in plan quality.

Innovation Solution

Utilizing a trained machine learning model, such as an artificial neural network, to generate fluence maps based on patient anatomy projections, optimizing fluence distributions for improved radiotherapy planning and reducing the need for manual adjustments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional offline treatment planning with manual trial-and-error optimization is used, then the treatment plan can be customized for each patient, but the process is time-consuming and subjective

Engineering Contradiction:
Improveplan quality accuracyVSAvoidtreatment plan creation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The system performs preliminary actions by pre-training the neural network model on extensive treatment plan data before actual treatment planning. This pre-computed knowledge enables rapid generation of accurate fluence maps during clinical use, eliminating the need for time-consuming manual trial-and-error optimization while maintaining high plan quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical trial-and-error optimization process with an artificial neural network-based system. The neural network learns complex optimization patterns from training data and automatically generates optimized fluence maps, substituting manual planner efforts with automated intelligent computation that is both faster and more consistent

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If the number of organs-at-risk increases, then the treatment plan complexity increases, but the difficulty of sparing critical organs increases significantly

Engineering Contradiction:
Improvehandling complex anatomiesVSAvoidoptimization process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The neural network transforms the complex multi-constraint optimization problem into a parameter estimation problem. By learning from training data containing multiple organs-at-risk scenarios, the network internalizes complex spatial relationships and dose constraints, enabling it to handle complex anatomies through parameter optimization rather than explicit constraint satisfaction

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces anatomy projection images as an intermediary representation between the complex 3D anatomical data and the fluence map generation process. This 2D projection view simplifies the input complexity while preserving essential anatomical information, making the problem more tractable for the neural network to process

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If manual treatment planning is used, then the planner can apply clinical judgment, but the process is subjective and leads to uncertainty in plan quality

Engineering Contradiction:
Improveplan quality consistencyVSAvoidplanning process simplicity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system incorporates feedback mechanisms through the neural network's learning process, where the model continuously improves by learning from training data containing optimal treatment plans. This feedback loop enables the system to capture and reproduce expert clinical judgment patterns, providing consistent and reliable plan quality without subjective variation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The neural network performs self-service by automatically generating optimized fluence maps without requiring manual intervention. The system serves itself by using the trained model to directly produce treatment plans, eliminating the need for planners to repeatedly apply subjective judgment while maintaining consistency across all cases

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4200872B1Machine learning optimization of fluence maps for radiotherapy claim for priority
Publication Date: 2025.10.22 ELEKTA AB
  • EP4200872B1 patent drawingFigure 1
  • EP4200872B1 patent drawingFigure 2A
  • EP4200872B1 patent drawingFigure 2B

AI summary

Systems and methods are disclosed for generating fluence maps for a radiotherapy treatment plan that uses machine learning prediction. The systems and methods include identifying image data that indicates treatment constraints for target dose areas and organs at risk areas in an anatomy of the subject, generating anatomy projection images that represent a view of the subject from respective beam angles, using a trained neural network model to generate the computer-simulated fluence map representations based on the anatomy projection images, where the fluence maps indicate a fluence distribution of the radiotherapy treatment at each of the beam angles.