Radiation Therapy Dose Evaluation via Contour Distance Analysis

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Solution Overview

Problem

Inaccuracies in the contours of anatomic structures during radiation therapy treatments, due to deformations and image registration errors, limit the accuracy of dose distribution evaluations and re-planning processes, affecting the estimation of doses absorbed by target structures and organs at risk.

Innovation Solution

A system and method that evaluate the dose distribution in varying distances from the contour of anatomic structures to determine points where specific conditions are met, allowing for the assessment of contour errors' impact on dose evaluations, and visualize these points to users, enabling better accuracy in radiation therapy planning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If deformable image registration is used to determine contour positions and shapes, then the treatment plan can be adapted to changed positions, but inaccuracies in the registered contours limit the accuracy of dose distribution evaluation

Engineering Contradiction:

Improveadaptability of treatment plan to changed positionsVSAvoidaccuracy of contour position determination

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system evaluates the dose distribution at multiple distances from the contour and provides feedback information about the impact of contour inaccuracies on dose evaluation accuracy. This feedback loop allows clinicians to assess whether the contour uncertainty significantly affects the treatment plan validity, enabling informed decisions about plan adaptation or re-planning.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediate evaluation step between contour determination and final dose assessment. By evaluating dose distribution at varying distances from the contour and analyzing the impact of contour errors, the system creates an intermediary assessment that bridges the gap between uncertain contour measurements and critical dose evaluation, allowing for quantification of uncertainty impact.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If the planning image is acquired earlier to allow sufficient time for treatment planning, then the treatment plan can be optimized, but the positions and contours may change during the treatment period

Engineering Contradiction:

Improveoptimization capability of treatment planVSAvoidstability of target structure and OAR positions

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The system performs preliminary evaluation of dose distribution at multiple distances from the contour during the planning phase. This preliminary action assesses the robustness of the treatment plan against potential contour variations before treatment begins, allowing clinicians to evaluate whether the optimized plan remains valid despite positional changes that may occur during the treatment period.

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If deformations of patient anatomy are accounted for by acquiring further images, then the accuracy of contour positions can be improved, but the transformed contours still include errors from image registration inaccuracies

Engineering Contradiction:

Improveaccuracy of contour position determinationVSAvoidcomplexity of image registration process

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the need for complex mechanical re-positioning or repeated imaging with a computational approach. By evaluating dose distribution at multiple distances from the contour and analyzing the sensitivity to contour variations, the system substitutes physical re-measurement with mathematical evaluation, reducing the need for additional complex imaging and registration procedures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11383103B2Evaluation of an anatomic structure with respect to a dose distribution in radiation therapy planning

Publication Date: 2022.07.12 ELEKTA AB

AI summary

The invention relates to a system for assisting in evaluating a contour of an anatomic structure (22) with respect to a dose distribution corresponding to a treatment plan for a radiation therapy treatment of a patient. The system comprises an evaluation unit particularly configured to evaluate the dose distribution in varying distances from the contour of the anatomic structure (22) to determine at least one point where the evaluated dose distribution fulfills a predetermined condition, and to determine the distance between the at least one point and the contour and/or to visualize the at least one point to a user of the system.