Diffusion Fluence Map Generation for Accurate Radiation Planning

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Solution Overview

Problem

Current methods for generating fluence maps in radiation therapy lack the ability to accurately predict detailed information from CT images, resulting in fluence maps that are too smooth and differ significantly from real images, necessitating skilled planners and extensive optimization time for effective dose distribution.

Innovation Solution

Employing a denoising diffusion probabilistic model as a deep learning model to generate high-quality fluence maps by inputting radiation information at each beam angle into a fluence map generative model, utilizing likelihood estimation to improve the accuracy and quality of fluence map generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a convolutional neural network is used to predict fluence map from CT image, then the generation speed is improved, but the prediction accuracy deteriorates resulting in fluence maps that are too smooth and differ significantly from real images

Engineering Contradiction:
Improvefluence map generation speedVSAvoidfluence map prediction accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary refinement process between the initial CNN prediction and the final fluence map. The method uses the predicted fluence map as an initial guess and iteratively refines it by comparing with actual dose distribution and adjusting through optimization algorithms. This intermediary step bridges the gap between fast but inaccurate CNN prediction and accurate but slow traditional methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs preliminary action by using the convolutional neural network to generate an initial fluence map prediction before the final optimization. This preliminary fluence map serves as a head start for subsequent refinement processes, reducing the computational burden and iteration time required to achieve accurate results compared to starting from scratch with traditional optimization methods.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If traditional optimization methods are used to generate accurate fluence maps, then the fluence map quality is improved, but the optimization time increases significantly

Engineering Contradiction:
Improvefluence map qualityVSAvoidoptimization time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by using the convolutional neural network to generate an initial fluence map prediction that is already close to the optimal solution. This preliminary prediction significantly reduces the number of iterations required by subsequent optimization algorithms, thereby maintaining high fluence map quality while dramatically reducing the total optimization time compared to traditional methods that start from scratch.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements local quality by applying different processing strategies to different aspects of fluence map generation. The CNN model handles the global structure and general pattern prediction efficiently, while localized refinement algorithms focus computational resources on specific regions requiring higher precision. This division allows the system to achieve high overall quality without uniformly applying computationally expensive optimization across the entire fluence map.

Inventive Principle:
Principle #3Local quality

3Reliability

If skilled planners are involved to adjust fluence maps for effective dose distribution, then the treatment plan quality is improved, but the operational complexity increases

Engineering Contradiction:
Improvetreatment plan qualityVSAvoidplanning process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements self-service by enabling the system to automatically generate and optimize fluence maps with minimal human intervention. The integrated approach combines AI prediction with automated optimization algorithms that can independently adjust fluence maps to achieve effective dose distribution. This reduces reliance on skilled planners while maintaining treatment plan quality, thereby reducing operational complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent incorporates feedback mechanisms where the system continuously evaluates the generated fluence maps against desired dose distribution criteria and automatically adjusts parameters to improve results. This closed-loop feedback system ensures high treatment plan quality by iteratively refining the fluence maps based on performance metrics, reducing the need for manual expert intervention and simplifying the overall planning process.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS12533529B2Fluence map generation method, treatment plan generation method, and electronic device
Publication Date: 2026.01.27 OUR UNITED CORP
  • US12533529B2 patent drawing
  • US12533529B2 patent drawing
  • US12533529B2 patent drawing

AI summary

A fluence map generation method includes: determining radiation information of a target volume at each beam angle of a plurality of beam angles, the target volume including a target area and organs at risk; and inputting the radiation information of the target volume at each beam angle into a fluence map generative model based on a denoising diffusion probabilistic model to obtain a fluence map corresponding to each beam angle. The fluence map corresponding to each beam angle is used to indicate an intensity of each beamlet corresponding to each beam angle in the target volume.