Radiation Detector Recalibration Using Pixel Threshold Shifts
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Solution Overview
Problem
Existing calibration methods for radiation detectors, particularly X-ray detectors in CT systems, are time-consuming and complex, requiring complete retuning due to image quality artifacts and noise effects, which incorporate measurement and evaluation noise, leading to invalidation of tuning tables.
Innovation Solution
A method for recalibration of radiation detectors that involves detecting a similar radiation spectrum to a previous calibration, measuring energy-dependent count rates, and ascertaining pixel-individual shift values to update signal threshold values, allowing recalibrated signal threshold value-signal energy value pairs to be determined without full re-measurement, thus reducing complexity and time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complete retuning is performed to address image quality artifacts and noise effects, then measurement precision is improved, but time consumption and complexity increase significantly
Solution Approach 1:
The recalibration process is segmented into two parts: a complete initial calibration that establishes reference values, followed by a simplified recalibration that only measures shifts relative to those references. This segmentation allows the time-consuming full calibration to be performed once, while subsequent recalibrations focus only on detecting changes, thereby reducing time consumption while maintaining precision.
Solution Approach 2:
Reference signal threshold value-count rate pairs are ascertained in advance during the initial calibration. These pre-established references serve as a baseline for subsequent recalibrations, eliminating the need to perform complete recalibration measurements each time. The preliminary action of establishing these references enables faster, less complex recalibration procedures while preserving measurement accuracy.
2Reliability
If complete retuning is performed to address image quality artifacts, then reliability is improved, but device complexity increases
Solution Approach 1:
The method extracts only the essential recalibration information (shift values of signal threshold values) from the complete calibration process. By taking out and measuring only the changes relative to reference values, rather than repeating the entire calibration procedure, the complexity of the recalibration procedure is reduced while maintaining the reliability needed to address image quality artifacts.
Solution Approach 2:
Instead of performing the full calibration action every time, the method applies partial action by measuring only the shifts in signal threshold values relative to established references. This partial recalibration is sufficient to maintain reliability for correcting image artifacts without requiring the complete, complex retuning procedure, thus reducing device complexity while preserving reliability.
3Manufacturing precision
If pixel-individual shift values are ascertained for all pixels, then manufacturing precision is improved, but measurement effort increases
Solution Approach 1:
The method uses reference signal threshold value-count rate pairs that were ascertained once during initial calibration as templates or copies. During recalibration, instead of performing complete measurements on all pixels, the system measures only the shifts relative to these reference copies. This copying approach maintains manufacturing precision by preserving the original calibration quality while improving productivity by avoiding redundant full measurements.
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
The recalibration method reduces the effort and time required for recalibration, improves image quality by suppressing noise effects, and maintains high detector resolution, enabling precise adjustment of energy thresholds without full retuning.
Implementation Method 1
an X-ray detector for detection of the X-ray radiation. The X-ray detector comprises a detection unit which generates a detection signal for X-ray radiation striking the detection unit
Data Source
AI summary
A method for calibration of a radiation detector with a plurality of pixels is described. In the method, the radiation detector is recalibrated via recalibrated signal threshold value-signal energy value pairs. A recalibration facility is also described. Moreover, a radiation detector and an imaging system are described.