Radiotherapy QA Using Couch Motion for Beam Tracking Accuracy

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Solution Overview

Problem

Existing radiotherapy devices with tracking capabilities require expensive and complex phantoms to simulate target region motion for quality assurance, limiting their effectiveness and accessibility.

Innovation Solution

A method and apparatus that use a subject support surface to simulate target region motion, allowing a beam delivery device to deliver a planned radiation dose to a moving target region, with a control system to verify the accuracy of beam tracking and dose delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a specialised phantom with in-built motors is used to simulate target region motion, then the ability to account for motion during treatment is improved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvemotion simulation accuracyVSAvoidphantom complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a simple phantom that copies or replicates the target region's motion characteristics without requiring complex internal mechanisms. The motion is transferred to the phantom from an external source (patient's actual motion or motion data), allowing the phantom to accurately represent target region movement while maintaining simplicity in its construction.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent introduces an intermediary approach where the phantom serves as a mediator between the patient's motion and the treatment delivery system. Rather than making the phantom itself complex with motors, the system uses motion data or external motion transfer mechanisms to enable the phantom to represent target region motion accurately.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a specialised phantom with in-built motors is used to simulate target region motion, then the ability to account for motion during treatment is improved, but the cost increases significantly

Engineering Contradiction:
Improvemotion simulation accuracyVSAvoidphantom cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a simple, inexpensive phantom construction that can be manufactured at low cost. Rather than investing in expensive phantoms with built-in motors, the solution uses affordable materials and designs that achieve the same functional outcome through external motion transfer or data-driven motion simulation.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent creates a simplified copy of the target region's motion characteristics using inexpensive means. The phantom replicates the essential motion patterns without requiring expensive internal mechanisms, achieving cost-effective motion simulation for treatment verification.

Inventive Principle:
Principle #26Copying

3Reliability

If a specialised phantom with limited range of motion is used, then the motion simulation capability is provided, but the adaptability to different motion patterns is reduced

Engineering Contradiction:
Improvemotion simulation capabilityVSAvoidmotion range
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal phantom design that can adapt to various motion patterns and ranges. By using external motion transfer mechanisms or data-driven approaches rather than fixed internal motors, the phantom can be configured to simulate different types of target region motions, making it versatile for various treatment scenarios.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent implements a dynamic motion simulation approach where the phantom's motion characteristics can be adjusted or changed based on the specific treatment requirements. Rather than being constrained by fixed motor ranges, the system can adapt to different motion patterns through external control or data input, providing flexibility across various clinical scenarios.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4308223B1System and method for assessing the performance of a radiotherapy apparatus
Publication Date: 2026.04.22 ELEKTA AB
  • EP4308223B1 patent drawingFigure 1
  • EP4308223B1 patent drawingFigure 2
  • EP4308223B1 patent drawingFigure 3

AI summary

Disclosed herein is a method for controlling a radiotherapy apparatus to perform quality assurance. The radiotherapy apparatus comprises a subject support surface, and a beam delivery device for delivering a planned radiation dose to a moving target region of a patient according to a plan, the plan comprising instructions for instructing the beam delivery device to adjust a positioning of a beam to compensate for motion of the target region. The method comprises receiving motion data, controlling movement of the subject support surface to simulate motion of the target region of the patient, based on the motion data, and controlling the beam delivery device to deliver radiation according to the plan while the subject support surface simulates motion of the target region.