Conformal Avoidance Radiation Planning Inversion

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Solution Overview

Problem

The complexity of tumor target definition in head and neck cancer radiation therapy, particularly in intensity-modulated radiation therapy (IMRT), leads to substantial physician planning time and discourages the use of effective IMRT techniques due to the difficulty in defining tumor volumes and surrounding lymph nodes.

Innovation Solution

A method that reverses the treatment planning process by defining areas of normal tissue and subtracting them from an encompassing field covering both normal and tumorous tissue, using a graphical user interface to simplify the planning process and reduce planning time, allowing for rapid treatment area definition based on easily identifiable normal tissue structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional target definition approach is used for IMRT planning, then treatment accuracy is improved, but physician planning time increases substantially

Engineering Contradiction:

Improvetreatment accuracyVSAvoidphysician planning time

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The patent inverts the conventional planning approach by starting with the complement set (normal tissue structures) rather than the target tumor volume. Physicians define normal tissue structures (parotid glands, spinal cord, etc.) that should receive reduced dose, and the treatment area is automatically determined by subtracting these from the field of view. This inversion transforms the complex task of delineating irregular tumor volumes and lymph nodes into the simpler task of outlining well-defined normal tissue boundaries.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts the definition task from the complex tumor target delineation and relocates it to the simpler normal tissue structure outlining. By removing the difficult-to-define tumor and lymph node regions from the planning process and replacing them with the extraction of normal tissue complements, the system achieves both accuracy and efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

If tumor volume and lymph node areas are defined for IMRT, then treatment conformance is improved, but planning complexity increases

Engineering Contradiction:

Improvetreatment conformanceVSAvoidplanning complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies inversion by reversing the logical set operation from 'define tumor and surrounding nodes' to 'define normal tissue and subtract from field'. This transforms the planning complexity from delineating multiple complex regions (tumor GTV, CTV, lymph nodes) to outlining simpler normal tissue structures with well-defined boundaries in standard imaging.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent segments the planning process into two distinct operations: (1) defining the field of view encompassing all relevant structures, and (2) identifying and subtracting normal tissue structures that require dose avoidance. This segmentation separates the complex radiation delivery planning from the simpler anatomical landmark identification, reducing overall planning complexity.

Inventive Principle:

Principle #1Segmentation

3Reliability

If conventional target definition approach is used, then treatment dose distribution is improved, but physician workload increases

Engineering Contradiction:

Improvetreatment dose distributionVSAvoidphysician productivity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent inverts the planning paradigm to achieve both reliable dose distribution and improved productivity. By defining normal tissue structures (parotid glands, spinal cord, etc.) that should receive minimal dose and subtracting these from the field of view, the system automatically generates treatment areas that ensure accurate dose delivery to tumors while protecting normal tissues, all with reduced physician time investment.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The system performs self-service by automatically calculating the treatment area as the complement of the defined normal tissue structures within the field of view. Once physicians outline the normal tissue boundaries, the computer automatically determines the treatment zone without requiring manual tumor contouring or lymph node delineation, thereby maintaining dose distribution reliability while significantly reducing physician workload.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS7508967B2Radiation treatment planning using conformal avoidance

Publication Date: 2009.03.24 WISCONSIN ALUMNI RES FOUND

AI summary

A system and method of radiation planning. The system and method are configured to implement or include the steps of (a) obtaining an image of a patient encompassing tumorous and non-tumorous tissue, (b) applying an encompassing field to the image having an area covering the tumorous and non-tumorous tissue, (c) using a graphical user interface to subtract subset fields from the encompassing field corresponding to radiation sensitive non-tumorous tissues to define a treatment area, and (d) inputting the treatment area to a computer program to generate a radiation treatment plan based on at least one prescribed dose to the treatment area.