Method for real-time motion monitoring and dose accumulation in magnetic resonance guided therapies using simultaneous orthogonal plane imaging
Inventors
Mickevicius, Nikolai • Paulson, Eric
Assignees
Publication Number
US-12076130-B2
Publication Date
2024-09-03
Expiration Date
2039-03-20
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Abstract
Systems and methods for providing image guidance for motion tracking and compensation in magnetic resonance imaging (“MRI”) guided therapies, such as MRI-guided radiation therapies using an MR-linac or other MRI-guided radiation therapy system, are described. Simultaneous orthogonal plane imaging (“SOPI”) is used to acquire images from a first slice that remains static throughout the acquisition, and from a plurality of slices that are orthogonal to the first slice. This first slice can be referred to in some instances as a “tracking” or “navigator” slice, and the plurality of slices that are orthogonal to the first slice can be referred to as “imaging” slices. The tracking slice images can be used to estimate motion of the subject that occurred during the data acquisition, and to track the position of targets (e.g., anatomical targets) during the delivery of radiation treatment.
Core Innovation
The invention introduces a method for real-time motion monitoring and dose accumulation in magnetic resonance guided therapies, specifically utilizing simultaneous orthogonal plane imaging (SOPI) in MRI-guided radiation therapy. SOPI allows for the simultaneous acquisition of images from a static tracker or navigator slice and from one or more orthogonal imaging slices, enabling spatially resolved imaging of motion during radiation therapy procedures.
In this approach, the navigator slice remains fixed throughout data acquisition, while orthogonal imaging slices change position, allowing continuous monitoring and retrospective sorting of imaging data into motion or respiratory phase bins. This enables the estimation of subject motion and tracking of anatomical targets or organs-at-risk during therapy delivery, allowing for real-time adjustment or gating of radiation based on detected movement.
The method overcomes limitations of existing systems by providing immediate, image-based feedback for motion monitoring without relying solely on surrogate signals or deformable registration. Dosimetric calculations and accumulation are improved by correlating imaging data with motion epochs, supporting adaptive updates to treatment plans based on actual delivered dose distributions over the course of therapy.
Claims Coverage
The patent contains a primary independent claim with several dependent claims, defining multiple inventive features based on the simultaneous acquisition and retrospective sorting of MRI images for real-time and retrospective motion management and dose calculation.
Simultaneous acquisition of static and orthogonal moving slices
A method wherein MRI data are acquired from a first, static slice (navigator slice) and a second, orthogonal slice with the position of the second slice changed during each repetition time. This pulse sequence is repeated such that the first slice remains static while the second slice sequentially covers the volume orthogonal to the first.
Concurrent acquisition of additional parallel navigator and imaging slices
The method allows for simultaneously acquiring data from a third slice parallel with the first (with its position changed in each repetition), and a fourth slice parallel with the second (with its position static), enabling dual navigator slice configurations for motion sorting.
Navigator-based retrospective binning and motion epoch formation
The first navigator slice is used to retrospectively bin images acquired at the second slice into motion bins, and the second navigator slice is used to bin images acquired at the third slice, supporting phase-based dose calculation.
The claims cover the simultaneous, orthogonal, and dynamic acquisition of navigator and imaging slices for use in real-time MRI-guided therapy, emphasizing retrospective classification and motion compensation based on direct navigator slice information.
Stated Advantages
Provides real-time tracking of anatomical targets and organs-at-risk for improved control of radiation or other therapies during MRI-guided treatment procedures.
Enables accurate assessment and compensation of dose delivery by correlating imaging data with motion information during therapy, allowing for adaptive updates to future treatment plans.
Allows simultaneous acquisition of cine images for motion monitoring and the creation of serial 4D-MRI epochs, improving visualization and compensation of anatomical changes during treatment.
Can eliminate reliance on deformable registration algorithms for dose accumulation by providing direct, image-based 4D volumetric data with motion information.
Improves spatial and temporal resolution of motion monitoring, enabling more precise dose accumulation through navigator-driven retrospective binning.
Permits super-resolution reconstruction of isotropic 4D-MRI volumes from orthogonal low-resolution datasets, enhancing the accuracy of anatomy delineation for therapy planning.
Documented Applications
MRI-guided radiation therapy (MR-gRT), including use with integrated MRI-linac systems for adaptive and real-time radiation treatment.
Real-time motion monitoring and gating during MRI-guided radiation therapy to control radiation delivery based on target or organ-at-risk (OAR) movement.
Dose accumulation and adaptive treatment planning in MRI-guided therapies by calculating and updating dose distributions based on actual anatomical motion tracked during therapy.
Use in other MRI-guided therapies, such as ultrasound treatment, where real-time monitoring of anatomic targets is required.
Phantom and volunteer studies for validating dose delivery and motion assessment in research and clinical workflow development.
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