MRI Radiotherapy Apparatus with Split RF Array
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Solution Overview
Problem
The limited space within cylindrical superconducting magnets used in magnetic resonance imaging (MRI) systems poses a challenge for positioning a target zone at the rotational axis of radiotherapy sources during MRI-guided radiotherapy, restricting the ability to optimize therapeutic efficacy.
Innovation Solution
The system eliminates the volume body coil, utilizing multiple transmit-and-receive coils and a split multi-element RF array to free up space, allowing for 6-dimensional subject movement and positioning of the target zone at the rotational axis of the LINAC beam, while maintaining compatibility with existing subject handling systems and carbon fiber table tops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a volume body coil is used in the MRI system, then MRI data acquisition is enabled, but space within the magnet is insufficient for positioning the target zone at the rotational axis of the radiotherapy source
Solution Approach 1:
The single volume body coil is segmented into multiple local transmit-and-receive coils distributed around the subject. These coils are positioned at different locations (e.g., head, torso, limbs) to collectively cover the entire subject volume, freeing up central space while maintaining comprehensive MRI coverage capability
Solution Approach 2:
The MRI coverage is transitioned from a centralized volumetric approach to a distributed spatial arrangement. Multiple coils are placed at different spatial dimensions around the subject, creating a networked sensing system that achieves whole-body coverage without occupying the central bore space
2Adaptability or versatility
If the radiotherapy source rotates about the magnet axis, then multiple angle irradiation is achieved, but the target zone cannot be positioned at the rotational axis due to limited space
Solution Approach 1:
The centralized MRI system is segmented into distributed local coils that can be independently positioned. This segmentation allows the central bore space to be cleared for target zone positioning while the distributed coils maintain comprehensive imaging capability through coordinated operation
Solution Approach 2:
Multiple local coils act as intermediaries to provide MRI coverage. Instead of a single central coil blocking the path, these intermediary coils are placed around the subject to indirectly achieve the same imaging function while clearing the central space for target positioning
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 enables more precise and efficient positioning of the target zone, maximizing therapeutic efficacy by allowing the target anatomy to be placed at the center of rotation of the LINAC beam, minimizing radiation exposure to surrounding tissues, and optimizing MRI data acquisition without physical interference with the therapy beam.
Implementation Method 1
The magnetic resonance imaging system comprises a magnet for generating a magnetic field within an imaging zone
Implementation Method 2
a radiotherapy source for directing electromagnetic radiation into the target zone
Data Source
AI summary
A therapeutic apparatus comprising a radiotherapy apparatus for treating a target zone and a magnetic resonance imaging system for acquiring magnetic resonance imaging data. The radiotherapy apparatus comprises a radiotherapy source for directing electromagnetic radiation into the target zone. The radiotherapy apparatus is adapted for rotating the radiotherapy source at least partially around the magnetic resonance magnet. The magnetic resonance imaging system further comprises a radio-frequency transceiver adapted for simultaneously acquiring the magnetic resonance data from at least two transmit-and-receive channels. The therapeutic apparatus further comprises a processor and a memory containing machine executable instructions for the processor. Execution of the instructions causes the processor to: calibrate the transmit-and-receive channels; acquire the magnetic resonance data; reconstruct a magnetic resonance image; register a location of the target zone in the image; and generate radiotherapy control signals using the registered image.