Inverse Planning for Radiation Dose Conformality

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Solution Overview

Problem

Conventional radiation treatment planning methods face challenges in achieving optimal conformality and homogeneity due to reliance on anatomical images alone, which lack molecular and chemical information, and require tedious manual processes to integrate functional image data, leading to inaccuracies and inefficiencies.

Innovation Solution

The development of an inverse planning process that automatically identifies regions of high cell density from functional images like PET, allowing for customized radiation dose distribution by overlaying functional image data with anatomical images, enabling automated contour generation and dose constraint application for precise radiation delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional forward treatment planning is used, then the treatment planning process is straightforward, but independent control of tumor dose and healthy tissue dose is not achieved, resulting in suboptimal conformality

Engineering Contradiction:
Improvedose conformalityVSAvoidplanning complexity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent applies inverse planning methodology where instead of calculating dose distribution from a given beam configuration (forward planning), the system starts with desired dose constraints for tumor and healthy tissue, then automatically determines the optimal beam directions, weights, and configurations to achieve those constraints. This inversion enables independent control of tumor dose and healthy tissue dose, resolving the contradiction between dose conformality and planning complexity.

Inventive Principle:
Principle #13The other way round (Inversion)

2Loss of information

If manual integration of functional image data is performed, then anatomical and functional information can be combined, but the process is tedious and prone to inaccuracies

Engineering Contradiction:
Improvefunctional image data integrationVSAvoidmanual processing time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The system implements automated contour generation by having the software automatically identify and delineate tumor sub-regions based on functional image data (such as PET scan intensity variations) without requiring manual intervention. The system self-corrects and self-optimizes the contour generation process, eliminating the tedious manual integration process while preserving all functional image information, thus resolving the contradiction between information retention and processing time.

Inventive Principle:
Principle #25Self-service

3Reliability

If uniform radiation dose is applied to the entire tumor volume, then delivery is simple, but regions of high cell density receive insufficient dose reducing treatment efficacy

Engineering Contradiction:
Improvetreatment efficacyVSAvoiddose distribution complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by differentiating the tumor volume into sub-regions based on functional image characteristics (e.g., high intensity regions indicating high cell density). Each sub-region is assigned different dose constraints and optimization weights, allowing the treatment plan to deliver higher doses to aggressive sub-regions while maintaining appropriate doses to less aggressive areas. This localized differentiation improves treatment efficacy without requiring overly complex delivery mechanisms, as the complexity is managed through software-based dose optimization.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS7400755B2Inverse planning using optimization constraints derived from image intensity
Publication Date: 2008.07.15 ACCURAY LLC
  • US7400755B2 patent drawing
  • US7400755B2 patent drawing
  • US7400755B2 patent drawing

AI summary

A method of automatically identifying a region of differing intensity in a functional image is described.