MR Projection Imaging for Radiation Therapy Motion Tracking
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Solution Overview
Problem
Current radiation therapy planning and delivery systems face challenges in accurately adapting to target region motion, particularly due to long imaging acquisition times and latency, which can result in deformation or movement of the target region between imaging and treatment, complicating the process and increasing complexity with multiple organs at risk.
Innovation Solution
The use of MR projection imaging techniques for both simulation and intrafractional imaging to provide real-time or near-real-time adaptation of radiation therapy, allowing for reduced acquisition latency and improved correlation with beam-eye-view portal imaging without exposing the subject to ionizing radiation, enabling more precise localization and prediction of the target region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional 3D MR imaging is used for treatment planning, then comprehensive anatomical information is obtained, but imaging acquisition time is long causing target region motion and deformation between imaging and treatment
Solution Approach 1:
The patent extracts only the essential projection information needed for treatment planning and delivery, rather than acquiring complete 3D volumetric data. By using projection imaging techniques, the system obtains the critical anatomical and positional information required for radiation therapy while significantly reducing acquisition time, thus resolving the contradiction between comprehensive anatomical information and long imaging time.
Solution Approach 2:
The system employs periodic projection imaging during the treatment process, acquiring images at regular intervals to track target region motion. This periodic acquisition strategy provides timely updates on anatomical changes without requiring continuous long-duration imaging, thereby maintaining measurement precision while minimizing time loss.
2Measurement precision
If frequent imaging is performed to track target motion, then motion accuracy is improved, but imaging latency and acquisition time increase
Solution Approach 1:
The patent replaces conventional mechanical 3D MR imaging systems with a projection imaging system that can rapidly acquire 2D projection data. This substitution enables frequent imaging acquisitions with minimal latency, as projection imaging requires much shorter scan times compared to volumetric imaging, thus improving target motion tracking accuracy without significant time penalty.
3Loss of information
If multiple imaging modalities are used for treatment planning, then imaging information completeness is improved, but system complexity and treatment planning time increase
Solution Approach 1:
The patent makes the MR imaging system multi-functional by enabling it to perform both treatment planning imaging and intrafractional motion tracking using projection imaging techniques. This universality eliminates the need for separate imaging modalities, reducing system complexity while maintaining imaging information completeness through a single integrated system.
Solution Approach 2:
The system merges treatment planning and motion tracking functions into a single projection imaging workflow. By combining these previously separate processes, the patent reduces the overall system complexity and treatment planning time while maintaining the completeness of imaging information needed for accurate radiation delivery.
4Measurement precision
If conventional imaging is used for motion tracking, then anatomical detail is maintained, but acquisition speed is slow affecting real-time adaptation
Solution Approach 1:
The patent segments the imaging process by using rapid projection imaging for motion tracking purposes, rather than attempting to capture all anatomical details in each image. This segmentation allows the system to prioritize acquisition speed for motion tracking while maintaining sufficient anatomical detail for treatment accuracy, resolving the contradiction between detail resolution and acquisition speed.
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 significantly reduces imaging acquisition time, improves registration consistency, and enhances the accuracy of radiation delivery by closely correlating imaging information with the anatomical state during treatment, effectively addressing motion-induced challenges and complexity with multiple organs at risk.
Implementation Method 1
nuclear magnetic resonance (MR) imaging
Data Source
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AI summary
Apparatus and techniques are described herein for nuclear magnetic resonance (MR) projection imaging. Such projection imaging may be used to control radiation therapy delivery to a subject, such as including receiving reference imaging information, generating a two-dimensional (2D) projection image using imaging information obtained via nuclear magnetic resonance (MR) imaging, the 2D projection image corresponding to a specified projection direction, the specified projection direction including a path traversing at least a portion of an imaging subject, determining a change between the generated 2D projection image and the reference imaging information, and controlling delivery of the radiation therapy at least in part using the determined change between the obtained 2D projection image and the reference imaging information.