MR Linac Tumor Gating With Real-Time Slice Registration

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Solution Overview

Problem

Existing radiation therapy treatment plans are challenged by changes in the position of target tumors during delivery, leading to misalignment and potential damage to surrounding healthy tissues due to the time-consuming and offline nature of current imaging and planning methods.

Innovation Solution

An adaptive image-guided therapy delivery system that utilizes real-time imaging and machine learning to rapidly acquire and register imaging slices, allowing for contemporaneous adjustments to the therapy protocol to align with the actual tumor position, incorporating deformable vector fields and machine learning models to determine and compensate for tumor movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If offline treatment planning and imaging methods are used, then treatment plan creation can be completed with sufficient detail, but the position of the target tumor changes during delivery leading to misalignment

Engineering Contradiction:
Improvetumor position accuracyVSAvoidtime delay between planning and treatment
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system transitions from static offline treatment planning to dynamic real-time adaptive planning. The treatment plan is continuously updated during radiation delivery based on real-time tumor position feedback from imaging, allowing the plan to adapt dynamically as the tumor moves throughout the treatment session.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system performs preliminary imaging and treatment planning before radiation delivery, then uses this information to guide real-time adjustments. The offline plan serves as a preliminary framework that is subsequently refined based on actual tumor position observations during treatment.

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If real-time imaging and adaptive planning are implemented, then tumor position accuracy is improved, but the complexity of the treatment delivery system increases

Engineering Contradiction:
Improvetumor position accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system merges multiple functions into an integrated adaptive treatment delivery system. Imaging acquisition, real-time image processing, tumor position tracking, and treatment plan modification are combined into a unified system that operates seamlessly during radiation delivery, reducing the need for separate independent systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system introduces an intermediary adaptive planning layer between the original treatment plan and actual beam delivery. This intermediary component processes real-time imaging data, calculates tumor position deviations, and generates corrected beam parameters, acting as a mediator that translates observed tumor position into appropriate treatment adjustments.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If traditional offline treatment planning is used, then the treatment process is simpler to execute, but surrounding healthy tissues may be damaged due to tumor movement

Engineering Contradiction:
Improvetreatment delivery simplicityVSAvoiddamage to healthy tissue
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The system implements feedback control by continuously monitoring tumor position through real-time imaging and using this information to adjust treatment parameters. The feedback loop compares actual tumor position against the planned position and automatically modifies beam targeting to compensate for deviations, preventing healthy tissue damage while maintaining treatment simplicity.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4013493B1Automatic gating with an mr linac
Publication Date: 2025.12.03 ELEKTA AB
  • EP4013493B1 patent drawingFigure 1A
  • EP4013493B1 patent drawingFigure 1B
  • EP4013493B1 patent drawingFigure 2

AI summary

Systems and methods are provided for registering images. The systems and methods perform operations comprising: receiving, at a first time point in a given radiation session, a first imaging slice corresponding to a first plane; encoding the first imaging slice to a lower dimensional representation; applying a trained machine learning model to the encoded first imaging slice to estimate an encoded version of a second imaging slice corresponding to a second plane at the first time point to provide a pair of imaging slices for the first time point; simultaneously spatially registering the pair of imaging slices to a volumetric image, received prior to the given radiation session, comprising a time-varying object to calculate displacement of the object; and generating an updated therapy protocol to control delivery of a therapy beam based on the calculated displacement of the object.