Dual-Energy CT Projection Correction for Metal Artifact Regions
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Solution Overview
Problem
Existing methods for correcting artifacts in medical images with metal regions, such as those caused by bone fixation bolts, suffer from errors in specifying the metal region, leading to blurring and inadequate correction due to interpolation processes.
Innovation Solution
An information processing apparatus and method that utilizes dual-energy CT to acquire and correct artifacts by comparing low-energy and high-energy projection data, employing interpolation and residual error reduction processes to enhance accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If metal region is specified from CT image, then artifact correction can be performed, but errors occur in metal region specification due to artifacts in the image
Solution Approach 1:
The patent performs preliminary actions by acquiring projection data at multiple energy levels before specifying the metal region. This allows the system to identify metal regions based on energy-dependent attenuation characteristics before artifact correction is attempted, thereby improving specification accuracy and preventing error propagation.
Solution Approach 2:
The patent introduces an intermediary approach by using projection data from multiple energy levels as a mediator to identify metal regions. Instead of directly specifying metal regions from artifact-contaminated CT images, the system uses energy-dependent projection data characteristics as an intermediate step to accurately locate metal regions.
2Manufacturing precision
If forward-projection of metal region image is performed, then projection data correction can be applied, but blurring occurs due to interpolation process
Solution Approach 1:
The patent applies parameter changes by performing forward-projection at multiple energy levels and combining the results. This approach changes the energy parameter dimension to avoid the blurring effect of single-energy interpolation, thereby maintaining image sharpness while achieving accurate projection data correction.
Solution Approach 2:
The patent uses a composite approach by combining forward-projection data from multiple energy levels. This is analogous to composite materials where multiple components are combined to achieve properties superior to individual components alone - in this case, the combined multi-energy data provides both correction precision and sharpness.
3Device complexity
If single-energy projection data is used, then processing is simpler, but artifact correction accuracy is insufficient
Solution Approach 1:
The patent transitions from single-energy to multi-energy processing by adding the energy dimension. This dimensional change enables more accurate metal region identification and projection data correction, as the energy-dependent attenuation characteristics provide additional information for distinguishing metal from surrounding tissues.
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
Improves the accuracy of artifact correction by reducing interpolation errors and restoring lost structures, ensuring clearer medical images.
Implementation Method 1
first projection data output from a detector that has detected radiation of a first energy transmitted through a subject and second projection data output from the detector that has detected radiation of a second energy transmitted through the subject
Data Source
AI summary
An information processing apparatus includes a processor, in which the processor acquires first projection data output from a detector that has detected radiation of a first energy transmitted through a subject and second projection data output from the detector that has detected radiation of a second energy transmitted through the subject, the second energy being different from the first energy, and performs a correction process of correcting artifacts in a region in which an amount of change between the first projection data and the second projection data is equal to or greater than a threshold value.