MR-CAT Synthesis for Accurate Radiotherapy Dose Planning
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Solution Overview
Problem
Current methods for creating electron density maps from magnetic resonance (MR) images, such as in integrated PET/MR systems or radiation therapy planning, face inaccuracies due to the non-unique correspondence between MR intensities and electron density, leading to potential errors in radiation dose distribution calculations.
Innovation Solution
A magnetic resonance imaging guided radiation therapy apparatus and method that acquires MR data, segments it into tissue types, creates a bulk electron density map, and recalculates radiation dose distributions interactively, allowing for modification and validation of the electron density map to ensure accuracy, thereby improving radiation therapy planning without the need for additional CT imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electron density maps are created from MR images using lookup operations, then the process is simple and fast, but the accuracy of the electron density map is poor due to non-unique correspondence between MR intensities and electron density
Solution Approach 1:
The patent introduces a synthetic CT image as an intermediary representation that bridges MR images and electron density maps. Instead of directly converting MR intensities to electron density (which is inaccurate), the system creates a synthetic CT image that combines MR anatomical information with estimated electron density, allowing for more accurate radiation dose calculations while maintaining the simplicity of the overall workflow.
Solution Approach 2:
The patent creates a synthetic CT image that copies and adapts MR image characteristics into a format suitable for radiation therapy planning. This synthetic representation replicates the functional requirements of a true CT scan (electron density information) without requiring actual CT imaging, thus improving accuracy while avoiding the need for additional imaging modalities.
2Measurement precision
If CT imaging is used for radiation therapy planning, then the accuracy of electron density map is high, but additional imaging resources and time are required
Solution Approach 1:
The patent makes the MR imaging system multi-functional by enabling it to serve both diagnostic purposes and radiation therapy planning purposes. The same MR image data is used to create both the diagnostic diagnosis and the treatment simulation, eliminating the need for separate CT imaging and saving time while maintaining planning accuracy through the synthetic CT approach.
Solution Approach 2:
The patent performs preliminary processing of MR images to create synthetic CT images that are ready for radiation therapy planning. By preparing the electron density information in advance from the MR data, the system eliminates the need for time-consuming CT scans while ensuring that accurate electron density maps are available for treatment simulation.
3Productivity
If MR images are used directly for radiation therapy planning, then no additional imaging is needed, but the accuracy of radiation dose distribution calculation is compromised
Solution Approach 1:
The patent changes the parameter representation from raw MR intensities to electron density values in the synthetic CT image. This parameter transformation allows the system to maintain the efficiency of using only MR imaging while achieving the precision required for accurate radiation dose distribution calculations, as the synthetic CT image contains properly scaled electron density information.
Data Source
AI summary
The present disclosure relates to a method for controlling a magnetic resonance imaging guided radiation therapy apparatus comprising a magnetic resonance imaging system. The method comprises: acquiring magnetic resonance data using the magnetic resonance imaging system and the pulse sequence from an imaging volume; segmenting the magnetic resonance data into a plurality of segments indicating respective tissues in the imaging volume; creating a bulk electron density map of the imaging volume from the plurality of segments; displaying the bulk electron density map and radiation dose distributions for the plurality of segments on a graphical user interface, wherein the radiation dose distributions are determined using the bulk electron density map; receiving a modification signal for modifying at least a first segment of the segments; recreating the bulk electron density map using the modified first segment, and recalculating the radiation dose distribution using the bulk electron density map; redisplaying the bulk electron density map and the radiation dose distributions on the graphical user interface.