Digital Volumetric Laminar Tomography for X-Ray Artifact Reduction
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Solution Overview
Problem
Existing x-ray systems face challenges in generating accurate tomographic images due to finite attributes of x-ray sources and detectors, aliasing, and systematic errors, which result in image artifacts and reduced reliability.
Innovation Solution
The implementation of digital volumetric laminar tomography (DVLT) using two-dimensional projection data to approximate x-ray behavior in a volume of interest, employing convolution and back projection algorithms to correct for systematic errors and optimize voxel geometries for improved density and spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If classical tomography with finite x-ray sources and detectors is used, then the system is practical and implementable, but image artifacts and reduced reliability occur due to aliasing and systematic errors
Solution Approach 1:
The patent applies preliminary action by performing corrections for systematic errors, aliasing, and detector inefficiencies during the data acquisition and preprocessing stages, before image reconstruction. This includes correcting for detector response variations, scatter radiation, and geometric distortions in advance, which prevents these issues from manifesting as artifacts in the final images and improves reliability without requiring complex post-processing
2Measurement precision
If conventional reconstruction algorithms are used, then the process is straightforward, but random errors exceed acceptable limits and image quality deteriorates
Solution Approach 1:
The patent implements feedback mechanisms through iterative reconstruction algorithms that continuously refine the image reconstruction process. The system compares reconstructed images with the original projection data, identifies discrepancies, and adjusts the reconstruction parameters accordingly. This feedback loop reduces random errors and improves measurement precision by systematically minimizing the difference between measured and reconstructed data across multiple iterations
Solution Approach 2:
The patent introduces intermediary processing steps including preprocessing filters, correction factors, and weighting functions that mediate between the raw projection data and the final reconstructed image. These intermediaries correct systematic errors, compensate for detector variations, and optimize the signal-to-noise ratio before reconstruction, thereby improving data precision without directly modifying the core reconstruction algorithm
3Quantity of substance
If scattered radiation detection is included, then complete x-ray data is captured, but image quality and reliability degrade due to scattered radiation interference
Solution Approach 1:
The patent applies the extraction principle by separating and removing scattered radiation components from the total detected x-ray signal. The system uses various techniques including scatter correction algorithms, energy discrimination, and spatial filtering to identify and extract the scattered radiation portion of the detected signal, then subtracts it from the total measurement. This allows complete data capture while eliminating the harmful scattered radiation component that degrades image reliability
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
DVLT enhances the accuracy and precision of x-ray attenuation data, reducing image artifacts and improving the quality of tomographic images by accounting for systematic errors and optimizing voxel geometries, thereby facilitating better diagnostic and treatment processes.
Implementation Method 1
x-ray source and the film, sometimes referred to as a 'detector,' move simultaneously in opposite directions
Implementation Method 2
x-ray attenuation data should reflect a set of different directions through each volume pixel, or voxel
Implementation Method 3
individual detectors may have different x-ray detection efficiencies and/or nonlinear properties, depending on the intensity of the transmitted x-rays
Data Source
AI summary
Systems and methods are provided for implementing an analytical approach to digital volumetric laminar tomography. The volumetric data visualizations generally take the form of volumetric images which approximate the spatial distribution of an x-ray attenuation coefficient throughout the region of interest in the object, such as a person, under examination. These visualizations are produced from a set of basic two dimensional data. One numerical technique employed in this regard takes the form of a process of convolution and back projection, where the convolution function is determined through the use of various analytic and empirical techniques.