Radiotherapy Motion Target Volume for Shape Change

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Solution Overview

Problem

Current radiotherapy systems fail to accurately account for changes in the shape of target volumes, such as tumors, during treatment, leading to potential underdosing or overdosing of the intended area and exposure of surrounding healthy tissues due to the assumption of a rigid tumor shape.

Innovation Solution

A system and method for generating a motion target volume that accounts for shape changes by receiving and co-registering multiple electronic medical images taken at different time points, using mathematical transformations to align the images and define a three-dimensional volume that encompasses the target region's varying shapes, thereby creating a more accurate representation for treatment planning and tracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If current radiotherapy systems assume a rigid tumor shape based on prior imaging, then the treatment planning process is simplified and faster, but the accuracy of radiation dose delivery deteriorates due to unaccounted shape changes

Engineering Contradiction:
Improveradiation dose delivery accuracyVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system transitions from assuming a static, rigid tumor shape to dynamically tracking and adapting to the tumor's changing shape during radiotherapy. Multiple images taken at different time points are co-registered to capture the tumor's motion and deformation, enabling the treatment system to adjust radiation delivery according to the actual tumor position and shape at each moment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary co-registration of multiple images taken at different time points before radiation delivery. By pre-establishing the relationship between images captured at different moments and positions, the system prepares accurate three-dimensional target volumes that account for tumor shape changes, enabling precise radiation dose delivery without requiring complex real-time adjustments during treatment.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If multiple electronic medical images are co-registered to account for tumor shape changes, then radiation dose delivery accuracy improves, but the processing time and computational complexity increase

Engineering Contradiction:
Improvetarget region shape measurement accuracyVSAvoidimage processing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The co-registration of multiple images and the generation of accurate three-dimensional target volumes are performed in advance, before radiation delivery begins. This preliminary processing allows the system to pre-calculate the tumor's motion patterns and shape changes, storing the results for rapid retrieval and application during treatment, thereby minimizing real-time processing delays.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system creates simplified digital representations (copies) of the tumor's three-dimensional shape and motion patterns from the co-registered images. These digital models serve as surrogates that can be quickly manipulated and applied during radiation delivery, avoiding the need for complex real-time image processing while maintaining measurement precision.

Inventive Principle:
Principle #26Copying

3Productivity

If the system tracks only the location of the target region assuming constant shape, then the tracking system remains simple, but the efficacy of radiotherapy deteriorates due to incorrect dose delivery

Engineering Contradiction:
Improveradiotherapy efficacyVSAvoidtracking system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The tracking system evolves from monitoring only the tumor's center position to dynamically tracking both the location and shape changes of the target region. By co-registering multiple images taken at different time points and positions, the system captures the tumor's deformation and motion patterns, enabling adaptive radiation delivery that maintains high efficacy while managing tracking complexity through efficient image processing algorithms.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3634577B1Systems and methods of accounting for shape change during radiotherapy
Publication Date: 2024.03.27 ELEKTA AB
  • EP3634577B1 patent drawingFigure 1
  • EP3634577B1 patent drawingFigure 2
  • EP3634577B1 patent drawingFigure 3A

AI summary

Embodiments of the disclosure may be directed to a system for generating a motion target volume representative of shape changes of a target region in a patient. The system may comprise at least one computer system configured to receive a plurality of electronic medical images that include the target region, and each of the plurality of images may have been taken at a different time point. The computer system may be configured to define a three-dimensional volume containing the target region in each of the plurality of images, and the three-dimensional volume may be different in at least two of the plurality of images due to differences in shape of the target region in the at least two images. The computer system may also be configured to co-register the three-dimensional volumes and generate the motion target volume, wherein the motion target volume encompasses each of the three-dimensional volumes.