MR-Guided Radiotherapy Real-Time Dose Recalculation
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Solution Overview
Problem
Current radiation therapy plans often lose accuracy due to daily variations in organ position, tumor size, and physiological processes, leading to increased damage to healthy tissue and side effects, as they rely on static images and do not account for real-time changes during treatment.
Innovation Solution
A magnetic resonance guided radiotherapy system that includes a bore-type magnet, split-type gradient coil, RF coil, radiation source, and processor-based controller to acquire pre-treatment and intra-treatment images, determine target and non-target volume contours and positions, and adjust radiation dose delivery in real-time to ensure precise targeting and minimize healthy tissue exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a static volumetric image is used to generate a therapy plan, then the planning process is simple and quick, but the therapy plan loses accuracy due to daily variations in organ position and tumor size
Solution Approach 1:
The patent transitions from static imaging to dynamic real-time imaging during radiation therapy delivery. The MRI system continuously acquires images of the target volume and surrounding tissues throughout the treatment session, allowing the system to adapt to daily variations in organ position and tumor size, thereby maintaining therapy plan accuracy without requiring excessive complexity
Solution Approach 2:
The system implements a feedback mechanism where real-time MRI images are acquired during radiation delivery, the images are processed to determine current positions and contours of target and non-target volumes, and this information is used to adjust the radiation dose distribution accordingly. This closed-loop feedback ensures accuracy while managing system complexity through automated processing
2Object-affected harmful factors
If a larger volume is irradiated to account for positioning uncertainties, then the therapeutic effect is maintained, but healthy tissue damage and side effects increase
Solution Approach 1:
By implementing real-time adaptive imaging and re-planning during treatment sessions, the system can dynamically adjust radiation delivery to match the actual position and size of the target volume. This eliminates the need to irradiate a larger safety margin volume, thereby reducing healthy tissue damage while maintaining reliable therapeutic effects through continuous monitoring and adjustment
Solution Approach 2:
The system changes the parameter of radiation dose distribution in real-time based on measured variations in target volume position and size. By adjusting dose parameters dynamically rather than using fixed margins, the system achieves reliable therapeutic effects with reduced exposure to healthy tissues
3Measurement precision
If a new therapy plan is generated when the target volume changes significantly, then the therapy plan accuracy is maintained, but treatment time increases
Solution Approach 1:
The patent implements continuous or near-continuous MRI imaging during the entire radiation therapy session, allowing for real-time detection of target volume changes. This continuous monitoring enables the system to maintain therapy plan accuracy throughout treatment without interrupting the overall process to generate completely new plans, thereby minimizing treatment time loss while preserving precision
Solution Approach 2:
The real-time feedback from continuous MRI imaging allows the system to detect significant changes in target volume and automatically adjust the radiation plan during treatment. This feedback mechanism maintains accuracy while avoiding the time penalty of stopping treatment to manually re-plan, as adjustments can be made automatically or with minimal interruption
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 approach reduces radiation exposure to healthy tissue by allowing for real-time adjustments in radiation dose delivery based on actual target and non-target volume positions, improving the accuracy and effectiveness of radiation therapy while minimizing side effects.
Implementation Method 1
a bore-type magnet configured to generate a static magnetic field in an examination region
Implementation Method 2
a radiofrequency (RF) coil configured to induce and manipulate magnetic resonance in a subject in the examination region and/or acquire magnetic resonance data from the examination region
Implementation Method 3
a radiation source disposed laterally to the bore-type magnet, the radiation source being positioned to transmit the gamma rays or x-rays radiation beams through the magnet and gradient coil radiation translucent regions to an isocenter
Data Source
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AI summary
A combined magnetic resonance (MR) and radiation therapy system (10) includes a bore-type magnet (12) with a magnet radiation translucent region (16) which allows radiation beams to travel radially through the magnet and a split-type gradient coil (18) includes a gradient coil radiation translucent region (20) aligned to the magnet radiation translucent region (16). A radiation source (24), disposed laterally to the magnet, administers a radiation dose through the magnet and gradient coil radiation translucent regions (16, 20) to an examination region (14). A dosage unit (66) determines the actual radiation dose delivered to each voxel of a target volume (30) and at least one non-target volume based on a pre-treatment, intra-treatment, and/or post-treatment image representation of the target volume (30) and the at least one non-target volume. A planning processor (60) updates at least one remaining radiation dose of a radiation therapy plan based on the determined actual radiation dose.