X-ray CT Image Reconstruction Using Constrained Iterative Correction
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Solution Overview
Problem
The existing iterative approximation projection data correction process in X-ray CT apparatuses requires significant time to process due to its application across all detection elements, leading to inefficiencies in image reconstruction.
Innovation Solution
The X-ray CT apparatus employs an application range determining unit to limit the iterative approximation projection data correction process, using a smoothing coefficient for correction intensity, and performs the correction only within determined ranges to generate correction projection data for image reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If iterative approximation projection data correction process is applied to all detection elements, then image quality (noise reduction) is improved, but calculation time increases enormously
Solution Approach 1:
The patent divides the detection elements into two groups: a first group of detection elements for which iterative approximation projection data correction is performed, and a second group for which it is not performed. This segmentation allows the system to apply the computationally intensive correction process only where necessary, thereby reducing overall calculation time while maintaining image quality in critical regions.
Solution Approach 2:
The patent applies different processing qualities to different regions by performing iterative approximation correction only on specific detection elements (first group) while using standard processing for others (second group). This local quality approach optimizes resource allocation by applying high-quality processing only where it provides the most benefit, balancing image quality with computational efficiency.
2Measurement precision
If iterative approximation projection data correction process is applied to all detection elements, then noise reduction is achieved, but processing efficiency deteriorates
Solution Approach 1:
The patent segments detection elements into first and second groups, applying iterative approximation correction only to the first group. This segmentation maintains noise reduction capabilities in critical areas while significantly improving overall processing efficiency by avoiding redundant computations on all detection elements.
Solution Approach 2:
The patent implements partial action by applying iterative approximation correction to only a portion (first group) of detection elements rather than all elements. This partial application achieves sufficient noise reduction for diagnostic purposes while maintaining acceptable processing efficiency, avoiding the excessive computation that would result from universal application.
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 the calculation time required for iterative approximation projection data correction and enables the generation of low-noise images according to examination purposes, improving image quality and processing efficiency.
Implementation Method 1
an X-ray generating device for irradiating an X-ray from the surroundings of an object; an X-ray detection device for detecting an X-ray transmitted through the object
Data Source
AI summary
To provide an X-ray CT apparatus that can reduce calculation time required for an iterative approximation projection data correction process by restricting a range for the iterative approximation projection data correction process and generate low-noise images according to the examination purpose, the calculation device of the X-ray CT apparatus generates correction projection data by performing an iterative approximation projection data correction process for projection data acquired in scanning and reconstructs CT images using the correction projection data. The calculation device determines a range to which iterative approximation projection data correction process is applied based on scanning conditions and reconstruction conditions. For example, a slice direction application range is determined based on an X-ray beam width, and a channel direction application range is determined based on an FOV. The calculation device performs an iterative approximation projection data correction process for projection data corresponding to the determined application range to generate correction projection data.