Radiation Therapy Plan Evaluation Using LET-Based Dose Categorization

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Solution Overview

Problem

Current radiation therapy treatment planning methods fail to effectively optimize linear energy transfer (LET) distribution, leading to suboptimal treatment plans that can cause excessive damage to both tumor cells and surrounding healthy tissues, particularly due to inaccuracies in relative biological effectiveness (RBE) modeling and inadequate dose distribution optimization.

Innovation Solution

A method that categorizes dose distributions into 'Clean' and 'Dirty' doses based on LET thresholds, allowing for visualization and optimization of radiation therapy plans to minimize high LET doses in organs at risk (OAR) and maximize them in target volumes, using computer-based systems for parameter optimization to improve plan quality and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high LET radiation is used to increase cell damage to tumor cells, then treatment efficacy is improved, but damage to surrounding healthy tissues increases

Engineering Contradiction:
Improvetreatment efficacyVSAvoiddamage to healthy tissues
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by differentiating dose evaluation based on location: high LET doses are encouraged in target volumes (tumor) while being restricted in organs at risk (OAR). The system calculates separate dose metrics for different anatomical regions, allowing high biological effectiveness where needed while protecting sensitive structures nearby.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the radiation dose into two distinct categories: high LET dose and low LET dose. This segmentation allows independent evaluation and optimization of each dose type's distribution, enabling the system to maximize high LET dose in tumors while minimizing it in healthy tissues, thereby resolving the contradiction between efficacy and safety.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If conventional dose distribution optimization is used, then treatment planning is simplified, but LET distribution is not effectively optimized leading to suboptimal treatment plans

Engineering Contradiction:
Improvetreatment planning complexityVSAvoidtreatment plan quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces a new parameter category system that divides doses into high LET and low LET categories based on LET threshold values. This parameter change enables the optimization system to specifically control and evaluate LET distribution independently of conventional dose metrics, improving treatment plan quality without significantly increasing planning complexity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary evaluation layer that sits between dose calculation and treatment plan assessment. This intermediary system calculates separate high LET and low LET dose metrics, providing detailed feedback to guide optimization toward better LET distribution while maintaining compatibility with existing treatment planning workflows.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If RBE modeling is improved for accurate biological effectiveness assessment, then treatment accuracy is improved, but computational complexity and modeling requirements increase

Engineering Contradiction:
Improvebiological effectiveness accuracyVSAvoidmodeling complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent simplifies RBE modeling by changing the approach from continuous RBE calculation to categorical dose separation. By dividing doses into high LET and low LET categories based on LET thresholds, the system achieves accurate biological effectiveness assessment without requiring complex continuous RBE models, thereby improving measurement precision while controlling modeling complexity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11426606B2Method and system of evaluating a radiation therapy treatment plan
Publication Date: 2022.08.30 RAYSEARCH LAB
  • US11426606B2 patent drawing
  • US11426606B2 patent drawing
  • US11426606B2 patent drawing

AI summary

A method of evaluating a radiation therapy (RT) treatment plan for a treatment volume, divided into sub-volumes and having a target volume and one or more organs at risk, OAR. It includes obtaining a RT treatment plan; calculating the linear energy transfer, LET, in each sub-volume; dividing the dose distribution into doses of a first category and a second category in each sub-volume, wherein the first category comprises doses with energy depositions with an LET below a first LET threshold and the second category comprises doses with energy depositions with an LET above a second LET threshold; determining amounts of doses of the first and of the second category in each sub-volume; and performing an analysis of the quality of the RT treatment plan by metrics based on the obtained distribution of doses of the first and of the second category in the target volume and in the OAR.