Eddy Current Reduction Gantry for MRI-Guided Radiation Therapy
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Solution Overview
Problem
Current radiation therapy systems face challenges in tracking tumor motion during treatment sessions due to interference between MRI and radiation therapy apparatuses, leading to suboptimal therapeutic quality due to eddy currents and magnetic field interactions.
Innovation Solution
Incorporating an eddy current reduction apparatus into the radiation therapy system, which includes a gantry with internal structures that are electrically disconnected and arranged to break current loops, using materials like manganese zinc ferrite, and dynamically adjusting configurations to minimize eddy current intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an MRI apparatus is combined with a radiation therapy apparatus to provide real-time imaging during treatment, then tumor tracking capability is improved, but eddy current interference and magnetic field interactions occur that degrade image quality and therapeutic precision
Solution Approach 1:
The gantry structure is divided into multiple independent conductive segments that are electrically isolated from each other. This segmentation breaks the continuous current paths that would otherwise form large eddy current loops, thereby reducing the magnitude and impact of eddy currents generated during MRI operation while maintaining the structural integrity and shielding functionality of the gantry.
Solution Approach 2:
Different regions of the gantry are equipped with conductive structures having locally optimized properties. The conductive segments are strategically positioned and dimensioned to provide appropriate electromagnetic shielding in specific areas while minimizing eddy current generation in other regions. This local optimization allows the system to balance shielding requirements against eddy current reduction goals.
2Productivity
If the gantry rotates to deliver radiation therapy, then treatment delivery is enabled, but eddy currents are generated that create artifacts in MRI images and reduce targeting accuracy
Solution Approach 1:
The conductive shielding structure on the rotating gantry is segmented into electrically isolated sections. During gantry rotation, this segmentation prevents the formation of continuous eddy current loops that would otherwise be induced by the time-varying magnetic field. The result is reduced eddy current interference that improves MRI image quality and maintains tumor targeting accuracy throughout the treatment delivery process.
Solution Approach 2:
Electrically insulating materials or structures are introduced as intermediaries between adjacent conductive segments on the gantry. These intermediaries prevent electrical connection between segments while allowing the gantry to maintain its shielding functionality. This intermediary approach enables the gantry to rotate smoothly while minimizing eddy current generation and associated image artifacts.
3Object-affected harmful factors
If conductive shielding structures are added to the gantry to protect against magnetic field interference, then magnetic field shielding is improved, but eddy current loops are formed that generate interference during MRI operation
Solution Approach 1:
The conductive shielding structure is divided into multiple electrically isolated segments rather than forming a continuous loop. This segmentation maintains the local electromagnetic shielding effect of each segment while preventing the formation of large-scale eddy current loops. The insulated segments provide magnetic field protection without generating significant eddy current interference during MRI operation.
Solution Approach 2:
The conductive segments are positioned and dimensioned to provide localized electromagnetic shielding where it is most needed, such as protecting sensitive radiation therapy components from magnetic field interference. By concentrating shielding capability in specific regions rather than using continuous coverage, the system achieves effective magnetic field protection while minimizing the total eddy current generation.
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 solution effectively reduces eddy current interference, enhancing the quality of radiation therapy by minimizing artifacts in MRI images and improving the accuracy and effectiveness of tumor targeting during treatment.
Implementation Method 1
The eddy current reduction apparatus may include at least one structure, wherein each of the at least one structure may include a plurality of internal structures and at least some of the plurality of internal structures are electrically disconnected from each other
Implementation Method 2
The radiation therapy apparatus may be configured to apply therapeutic radiation to at least one portion of the ROI when rotating with a gantry
Implementation Method 3
The MRI apparatus may be configured to acquire magnetic resonance imaging data with respect to a region of interest (ROI)
Data Source
AI summary
The present disclosure relates to a system for radiation therapy. The system may include a magnetic resonance imaging (MRI) apparatus and a radiation therapy apparatus. The MRI apparatus may be configured to acquire magnetic resonance imaging data with respect to a region of interest (ROI). The radiation therapy apparatus may be configured to apply therapeutic radiation to at least one portion of the ROI when rotating with a gantry. The radiation therapy apparatus may include an eddy current reduction apparatus coupled to the gantry. The eddy current reduction apparatus may include at least one structure, wherein each of the at least one structure may include a plurality of internal structures and at least some of the plurality of internal structures are electrically disconnected from each other.