Integrating and Counting CT Detectors for Drift Correction
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Solution Overview
Problem
Dual-source CT systems face challenges with high drift in energy-selective counting detectors, requiring frequent calibration and limited dynamic range, which affects image quality and diagnostic accuracy.
Innovation Solution
A computed tomography system with two sets of detector elements, where integrating detector elements measure radiation over the entire energy spectrum and counting detector elements measure in multiple energy ranges, allowing for correction of energy-resolving measurements to reconstruct tomographic image datasets without prior calibration, and utilizing integrating measurements to correct counting detector data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If energy-selective counting detectors are used to measure radiation in multiple energy ranges, then energy resolution and material differentiation are improved, but detector drift increases and frequent calibration is required
Solution Approach 1:
The patent combines integrating detector elements and counting detector elements into a single detector unit, allowing both measurement modes to operate simultaneously. The integrating detector provides stable reference measurements that compensate for the drift in counting detectors, while maintaining energy resolution capabilities.
Solution Approach 2:
The system uses measurements from integrating detector elements as feedback to correct and normalize the measurements from counting detector elements. This feedback mechanism continuously compensates for detector drift without requiring external calibration during the scan.
2Loss of information
If counting detector elements are used for energy-resolving measurements, then spectral information is improved, but the dynamic range is limited and saturation occurs in high dose rate ranges
Solution Approach 1:
The patent merges the capabilities of integrating and counting detectors into a unified system where each detector type compensates for the other's limitations. The integrating detector handles high dose rates without saturation, while the counting detector provides spectral information in lower dose rate ranges.
Solution Approach 2:
The system dynamically changes the measurement parameters by switching between integrating and counting modes based on the radiation dose rate. In high dose rate situations, the integrating detector is used; in lower dose rate situations, the counting detector provides spectral resolution.
3Measurement precision
If frequent calibration of counting detectors is performed to compensate for drift, then measurement accuracy is maintained, but measurement time and system complexity increase
Solution Approach 1:
The integrating detector elements are used to perform preliminary normalization measurements that account for detector drift during the scan. This preliminary action eliminates the need for separate calibration steps between scans, as the normalization is performed continuously using the co-measuring integrating detectors.
4Manufacturing precision
If dual-source CT system with both integrating and counting detectors is used, then image quality and diagnostic accuracy are improved, but device complexity increases
Solution Approach 1:
The patent integrates both integrating and counting detector elements within a single detector unit rather than requiring separate detector systems. This merging approach maintains the dual-functionality needed for high image quality while reducing the overall system complexity and space requirements.
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 eliminates the need for frequent calibration of counting detectors, enhances spatial resolution, and improves contrast-to-noise ratio by correcting for detector drift and augmenting data in high dose rate ranges, thereby improving image quality and diagnostic accuracy.
Implementation Method 1
at least one first set of integrating detector elements measures incident radiation over the entire energy spectrum of the incident radiation in an integrating manner
Implementation Method 2
at least one second set of counting detector elements measures incident radiation in at least two energy ranges in a resolving manner
Implementation Method 3
by way of the integrating measurements of the at least one first set of integrating detector elements, the energy-resolving measurements of the at least one second set of counting detector elements are corrected
Data Source
AI summary
A method and a computed tomography system are disclosed for generating tomographic image datasets of a measurement object with multiple simultaneously operable sets of detector elements. In at least one embodiment, at least one first set measures incident radiation over the entire energy spectrum of the incident radiation in an integrating manner and at least one second set measures incident radiation in at least two energy ranges in a resolving manner, wherein furthermore by way of the integrating measurements, the energy-resolving measurements relating in each case to rays traversing a measurement object in a spatially identical manner are corrected and a tomographic image dataset of the measurement object is reconstructed at least from the corrected energy-resolving measurements.