Interior CT Reconstruction Without Prior Information
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Solution Overview
Problem
Conventional interior CT image reconstruction methods require prior information about the object, which is not always available, limiting their practicality and versatility, especially in cases where exact image reconstruction is needed without such information.
Innovation Solution
The method involves measuring additional projection data not passing through the Region Of Interest (ROI) and using a combination of differential reverse projection and truncation Hilbert transform in the Filtered Backprojection (FBP) process to achieve mathematically exact image reconstruction, even without prior information, by controlling the aperture angle of X-ray beams and utilizing Scout-View scan projection data or lower spatial resolution beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional interior CT image reconstruction methods are used, then image reconstruction can be performed, but the methods require prior information about the object which is not always available, limiting practicality and versatility
Solution Approach 1:
The patent introduces Scout-View scan projection data as an intermediary element that bridges the gap between incomplete interior CT projection data and the full object information needed for exact reconstruction. This additional data serves as a mediator that provides the missing information without requiring prior knowledge of the object's internal structure
Solution Approach 2:
The patent performs preliminary scanning (Scout-View scan) before the main interior CT measurement to obtain projection data of the entire object. This preliminary action collects additional information that will be used later to enable exact reconstruction of the ROI without requiring prior information about the object's internal characteristics
2Object-affected harmful factors
If only projection data passing through ROI is measured, then exposure dose and detector requirements are reduced, but mathematically exact image reconstruction becomes impossible
Solution Approach 1:
The patent applies partial action by measuring projection data only for the ROI region during the main scan, while obtaining only the necessary additional data from Scout-View scan. This avoids the excessive action of measuring all projection data through the entire object, thereby reducing exposure dose while still achieving exact reconstruction through the combination of partial measurements
3Adaptability or versatility
If approximate reconstruction methods are used, then image reconstruction can be performed without prior information, but errors occur in low frequency components and artifacts are generated
Solution Approach 1:
The patent uses Scout-View scan projection data as an intermediary to eliminate artifacts and low frequency errors that plague approximate reconstruction methods. This additional data acts as a corrective element that enables exact reconstruction without requiring assumptions about the object's internal structure
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 enables high-accuracy image reconstruction in interior CT, ensuring uniqueness of the solution and reducing artifacts, thus overcoming the limitations of conventional methods that rely on prior information.
Implementation Method 1
measuring line integral values of the physical quantity distribution within an object or body by radiating quantum beams through the object
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
[Object] Providing an interior CT image generation method for enabling the image reconstruction at high accuracy through the exact solution even in the case where the prior information cannot be used, i.e., being high in multiplicity of use. [Solving Means] An image generation method of an interior CT, comprising the following steps: a step for obtaining interior CT projection data by measuring only all of quantum beams passing through a region of interest (ROI) in an inside of photographing object in a geometrical system for CT measurement; and a step for obtaining partial entire projection data by measuring quantum beams passing through an entire of said photographing object from a segment in an outside of said photographing object in said geometrical system for CT measurement; wherein further including a processing step for exactly reconstructing said ROI upon basis of said interior CT projection data obtained and said partial entire projection data.