Compact RF Apparatus with Flexible Waveguide for Rotatable Gantries

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Solution Overview

Problem

Designing a beam generation subsystem for radiotherapy systems that enables high performance and versatile gantry movement is challenging due to the complexity and size of conventional RF apparatus, making it difficult to implement on a rotatable gantry.

Innovation Solution

The use of a compact RF apparatus with a three-port circulator and flexible waveguide arrangement, which reduces the overall size and allows stable RF power transmission, enabling efficient mounting on a rotatable gantry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional RF apparatus is used in radiotherapy systems, then reliable RF power transmission is achieved, but the device size and complexity increase, making it difficult to implement on a rotatable gantry

Engineering Contradiction:
ImproveRF power transmission stabilityVSAvoidRF apparatus size and complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The RF apparatus is divided into separate functional modules: a RF power source, a three-port circulator, and a transmission waveguide. This segmentation allows each component to be optimized independently and reduces the overall complexity while maintaining reliable RF power transmission to the acceleration waveguide.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A three-port circulator is introduced as an intermediary device between the RF power source and the transmission waveguide. The circulator manages RF power flow directionally, isolating the power source from reflections and ensuring stable power transmission, thereby reducing the complexity of direct connections.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If conventional RF apparatus is used, then sufficient RF power is provided, but the mechanical performance and versatility of the gantry are limited due to size constraints

Engineering Contradiction:
ImproveRF power outputVSAvoidGantry movement versatility
Core Design Contradiction:
PowerVSAdaptability or versatility

Solution Approach 1:

The transmission waveguide is designed to be flexible rather than rigid, allowing it to accommodate dynamic movements of the rotatable gantry. This flexibility enables the RF apparatus to maintain stable connections during gantry rotation and positioning, enhancing the versatility of the system without compromising RF power delivery.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The use of a flexible transmission waveguide allows the RF apparatus to adapt to the mechanical movements of the gantry. The flexible waveguide maintains RF power transmission while accommodating changes in position and orientation, thereby enabling versatile gantry movement without power loss.

Inventive Principle:
Principle #30Flexible shells and thin films

3Adaptability or versatility

If a compact RF apparatus is designed, then the gantry versatility is improved, but the stability of RF power transmission may be compromised

Engineering Contradiction:
ImproveGantry mounting flexibilityVSAvoidRF power transmission stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The three-port circulator provides automatic feedback control for RF power flow. It monitors the RF conditions and adjusts the power direction accordingly, ensuring stable power transmission to the acceleration waveguide while maintaining a compact apparatus design suitable for gantry mounting.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The circulator acts as an intermediary that stabilizes RF power transmission by isolating the power source from load variations and reflections. This intermediary component ensures reliable power delivery while maintaining the compact design needed for gantry versatility.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration facilitates improved mechanical performance and versatility of the gantry, allowing for more precise and efficient delivery of radiotherapy treatments by reducing system size and enhancing alignment with the rotatable gantry.

Implementation Method 1

The RF apparatus comprises an RF power source arranged to transmit RF power towards a three-port circulator along a first direction. The three-port circulator is arranged to transmit the RF power towards a transmission waveguide along that first direction.

Methodology Applied
Scientific EffectRF power transmission: Electromagnetic Induction

Implementation Method 2

The transmission waveguide is arranged to be coupled to an acceleration waveguide. The transmission waveguide is flexible and is arranged to accommodate mechanical movement of a rotatable gantry.

Methodology Applied
Scientific EffectWaveguide transmission: Waveguide

Implementation Method 3

The acceleration waveguide is arranged to accelerate electrons into a target to generate X-rays.

Methodology Applied
Scientific EffectElectron acceleration: Electromagnetic Induction

Implementation Method 4

The acceleration waveguide is arranged to accelerate electrons into a target to generate X-rays.

Methodology Applied
Scientific EffectX-ray generation: X-Ray

Data Source

PatentEP4642170A1Radiofrequency apparatus for a radiotherapy system
Publication Date: 2025.10.29 ELEKTA AB
  • EP4642170A1 patent drawingFigure 1
  • EP4642170A1 patent drawingFigure 2
  • EP4642170A1 patent drawingFigure 3

AI summary

Disclosed herein is radiofrequency, RF, apparatus for a radiotherapy system, the RF apparatus comprising an RF power source, a three-port circulator; and a transmission waveguide arranged to be coupled to an acceleration waveguide, wherein the RF power source is arranged to transmit RF power towards the three-port circulator along a first direction and the three-port circulator is arranged to transmit RF power towards the transmission waveguide along the first direction.