MRI-Guided Radiation Therapy Layout for Magnetic Interference Control

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Solution Overview

Problem

Existing radiation therapy systems face challenges in tracking subject motion during treatment sessions due to the difficulty in integrating MRI and radiation therapy apparatuses in a compact structure without causing interference, affecting therapeutic quality.

Innovation Solution

A radiation therapy system is designed with a linear accelerator positioned between shielding coils, a deflection magnet to correct electron dispersion, and correction coils to ensure electrons collide vertically on the target, minimizing magnetic interference and optimizing the compact arrangement of components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If MRI apparatus and radiation therapy apparatus are combined in a compact structure, then space utilization is improved, but magnetic field interference between components increases

Engineering Contradiction:
Improvesystem compactnessVSAvoidmagnetic field interference
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

A magnetic shielding structure is introduced as an intermediary element between the MRI apparatus and radiation therapy apparatus. This shielding structure, positioned between the two functional modules, blocks and redirects magnetic field lines to prevent interference between the MRI main magnetic field and the radiation therapy electron beam path, thereby enabling compact integration while maintaining functional independence

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The integrated system is divided into distinct functional modules (MRI apparatus module and radiation therapy apparatus module) that are spatially separated by the magnetic shielding structure. This segmentation allows each module to operate independently within the compact system, reducing mutual interference while maintaining overall system integration

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If linear accelerator is positioned between shielding coils, then space utilization is improved, but electron beam dispersion increases

Engineering Contradiction:
Improvecomponent arrangement compactnessVSAvoidelectron beam positioning accuracy
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

A deflection magnet is introduced as an intermediary component between the linear accelerator and target. This deflection magnet generates a controlled magnetic field that counteracts the dispersion effect caused by positioning the linear accelerator between shielding coils, thereby maintaining electron beam focusing accuracy while enabling compact component arrangement

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically adjusts the magnetic field parameters of the deflection magnet to compensate for electron beam dispersion. By changing the strength and orientation of the deflection magnetic field, the system maintains optimal electron beam positioning accuracy despite the compact arrangement of the linear accelerator between shielding coils

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If deflection magnet is added to correct electron dispersion, then electron beam accuracy is improved, but system complexity increases

Engineering Contradiction:
Improveelectron beam accuracyVSAvoidmagnetic component quantity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The deflection magnet is designed to serve multiple functions: it corrects electron beam dispersion, provides fine positioning control, and works in conjunction with the shielding coils to manage magnetic field distribution. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in system complexity while maintaining electron beam accuracy

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

4Manufacturing precision

If correction coils are added to ensure vertical electron collision, then therapeutic precision is improved, but device complexity increases

Engineering Contradiction:
Improveelectron collision precisionVSAvoidmagnetic component quantity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The correction coils are integrated with the existing magnetic field management system, working in combination with the shielding coils and deflection magnet. This merging approach allows the correction coils to enhance electron collision precision without requiring completely separate magnetic field control systems, thereby limiting the increase in device complexity while achieving vertical collision accuracy

Inventive Principle:
Principle #5Merging (Combining)

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

The system achieves improved magnetic field homogeneity and reduced interference, allowing for precise radiation delivery and real-time imaging guidance, enhancing therapeutic accuracy and compactness.

Implementation Method 1

a linear accelerator configured to accelerate electrons to produce a radiation beam

Methodology Applied
Scientific EffectElectron acceleration: Electromagnetic Induction

Implementation Method 2

a deflection magnet configured to deflect the electrons emitted from the linear accelerator by a deflection angle

Methodology Applied
Scientific EffectMagnetic deflection: Lorentz Force

Implementation Method 3

a plurality of main magnetic coils configured to generate a main magnetic field

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnet

Implementation Method 4

a plurality of shielding magnetic coils, the plurality of shielding magnetic coils being arranged around an axis

Methodology Applied
Scientific EffectMagnetic shielding: Magnetic Field

Data Source

PatentEP4142586B1Radiation therapy system
Publication Date: 2026.02.11 SHANGHAI UNITED IMAGING HEALTHCARE
  • EP4142586B1 patent drawingFigure 1
  • EP4142586B1 patent drawingFigure 2A
  • EP4142586B1 patent drawingFigure 2B

AI summary

The present disclosure is directed to a radiation therapy system. The radiation therapy system may comprise a magnetic resonance imaging (MRI) apparatus. The MRI apparatus may include a plurality of shielding magnetic coils, the plurality of shielding magnetic coils being arranged around an axis. The radiation therapy system may also comprise a radiation therapy apparatus, which includes a linear accelerator configured to accelerate electrons to produce a radiation beam, the linear accelerator being located between two neighboring shielding coils of the plurality of shielding coils, and a length direction of the linear accelerator being parallel with the axis. The radiation therapy apparatus may also include a deflection magnet configured to deflect the electrons emitted from the linear accelerator by a deflection angle in a first portion of a moving trajectory, the first portion of the moving trajectory being on a plane intersecting with a radial plane of the MRI apparatus.