X-ray Tomography Slice-by-Slice Reconstruction
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Solution Overview
Problem
Digital Tomosynthesis (DT) faces limitations due to incomplete projection datasets, leading to limited angle artefacts and incomplete 3D reconstruction, requiring extensive processing and high computational demands for image reconstruction.
Innovation Solution
A method utilizing an array of x-ray emitters and detectors to reconstruct images slice-by-slice, employing back-projection and weighting factors to produce average intensity images, followed by convolution with a ramp filter, allowing for interactive reconstruction and reduced memory demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional CT reconstruction methods are used to process the entire volume, then complete 3D information can be reconstructed, but the processing time is extensive and computational demands are high
Solution Approach 1:
The patent divides the 3D reconstruction process into discrete slices along the z-axis. Each slice is reconstructed independently using a 2D reconstruction algorithm, allowing parallel processing and significantly reducing computation time compared to processing the entire volume sequentially. This segmentation enables faster reconstruction while maintaining complete 3D information through systematic slice-by-slice processing.
2Measurement precision
If conventional CT reconstruction methods are used to process the entire volume, then complete 3D information can be reconstructed, but computational demands are high
Solution Approach 1:
The patent segments the volumetric reconstruction into independent 2D slice reconstructions. Each slice requires significantly less computational power than processing the entire 3D volume at once, enabling the use of less powerful computing hardware while achieving the same reconstruction quality. This reduces memory requirements and computational complexity from O(N³) to O(N²) per slice.
3Object-affected harmful factors
If DT is used to reduce radiation dose and provide 3D imaging, then lower radiation dose is achieved, but limited angle artefacts appear and 3D information is incomplete
Solution Approach 1:
The patent introduces a third dimension (z-axis slicing) to the traditional 2D DT reconstruction approach. By reconstructing multiple parallel slices at different z-positions, the system recovers 3D structural information that would be lost in single-plane DT. This dimensional extension allows complete volumetric reconstruction from limited-angle projections while maintaining low radiation dose benefits.
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
Enables faster and more efficient reconstruction of higher contrast images, particularly for thick objects, with the ability to reconstruct slices independently, reducing computational load and improving image quality.
Implementation Method 1
emitter panel comprising a plurality of x-ray emitters; emitting a respective cone of x-ray radiation from each emitter toward the detector panel
Implementation Method 2
producing respective attenuation images at the detector panel in response to each respective cone of x-ray radiation impinging the detector panel; reconstructing a density function indicative of attenuation of the x-ray radiation
Data Source
AI summary
The majority of image reconstruction algorithms are common to DT and CT, and require reconstruction volume allocation and are based on ray tracing techniques. Reconstructed three-dimensional images become available only after the entire volume is processed and the algorithm completes. The present invention performs reconstruction on a slice-by-slice basis, instead of waiting for completion of the algorithm by back-projecting each pixel in each attenuation image towards the emitter that generated that image, onto a selected reconstruction slice and determining a proportion of overlap with grid cells in the slice to obtain weighting factors in order to calculate an average back-projected intensity for each grid cell in the selected reconstruction slice.