Spatial Modulator for CT Image Error Correction
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Solution Overview
Problem
Computerized tomography (CT) systems face errors due to extraneous radiation and temporal lag effects, leading to spatial and temporal errors that result in artifacts, loss of resolution, and contrast degradation in image slices.
Innovation Solution
The implementation of a spatial modulator between the radiation source and the object, which introduces spatial and temporal perturbations in the radiation intensity, allowing for the estimation and subtraction of spatial and temporal errors from measured data, thereby improving image clarity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional CT imaging is performed without spatial modulation, then the imaging process is simple and quick, but spatial errors from scattered radiation and temporal errors from detector lag cause image degradation
Solution Approach 1:
A spatial modulator is introduced as an intermediary component between the radiation source and the object. This modulator patterns the incident radiation with known spatial and temporal characteristics, enabling the system to distinguish between primary radiation and scattered radiation, and to correct for detector lag effects through mathematical processing of the modulated signal
Solution Approach 2:
The spatial modulator applies periodic or patterned modulation to the radiation intensity in both space and time domains. This periodic action creates distinct signal patterns that allow the reconstruction algorithm to separate and correct for various error sources including scattered radiation and temporal lag, thereby improving image quality without significantly increasing overall system complexity
2Measurement precision
If radiation intensity is increased to improve signal quality, then image signal-to-noise ratio improves, but scattered radiation and temporal lag effects are amplified
Solution Approach 1:
The system converts the harmful effects of scattered radiation and temporal lag into useful information. By modulating the radiation pattern with known spatial and temporal characteristics, the system can identify and measure the magnitude of these error sources, then mathematically remove them from the final image reconstruction, effectively turning noise and artifacts into correctable data
3Measurement precision
If spatial modulation is applied to correct errors, then spatial and temporal errors are reduced, but data processing complexity increases
Solution Approach 1:
The spatial modulator applies preliminary spatial and temporal patterning to the radiation before it interacts with the object and detector. This preliminary action embeds known reference patterns into the measurement data, allowing the reconstruction algorithm to efficiently extract and correct errors without requiring complex iterative processing, thus reducing the overall computational burden
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 effectively reduces spatial and temporal errors, enhancing the quality of CT images by correcting for scattering, point-spread, and lagging effects, resulting in improved resolution and contrast.
Implementation Method 1
correcting for scattering, point-spread, and lagging effects
Implementation Method 2
the object, which will absorb some of the radiation based on its size, density, and atomic composition
Implementation Method 3
The source's radiation emanates toward the imaging device in a volume of space defined by a right-circular, elliptical, or rectangular cone having its vertex at the point source and its base at the imaging device
Implementation Method 4
The scintillation plate, which converts the radiation into light that can be readily detected by the semiconductor diodes
Implementation Method 5
Each semiconductor diode, which typically comprises amorphous silicon, generates pairs of free electrons and free holes in response to light received from the portion of the scintillation plate above it
Data Source
AI summary
Disclosed are systems, methods, and computer program products that generate estimates of errors caused by extraneous radiation in tomographic systems, such as cone-beam computerized tomography (CBCT) systems, fluoroscopic tomography systems, radiographic tomography systems, laminar tomography imaging systems, and the like. In one group of inventions, spatial errors are estimated from projection data collected where a known spatial perturbation has been introduced into radiation intensity of the source. In another group of inventions, temporal errors are estimated from a sequence of projections where a known perturbation in the radiation intensity of the source for different projections has been introduced.