X-ray Detector Signal Correction for Induction Noise
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Solution Overview
Problem
In computed tomography systems, quantum-counting X-ray detectors face challenges in maintaining high spatial resolution and contrast due to induction-based counting events from adjacent pixels, which can lead to worsened image quality, especially at the pixel edges, and increasing the minimum energy threshold to filter these events results in missing low-energy X-ray photons.
Innovation Solution
A method for correcting spatially resolved photon scans in X-ray detectors by defining reference values for electrical signals generated from incident X-rays, selecting upper and lower threshold values, and generating correction signals to differentiate between true and induced counting events, thereby improving image data sets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the minimum energy threshold is increased to filter induction-based counting events, then image contrast is improved, but low-energy X-ray photons are no longer detected
Solution Approach 1:
The patent segments the counting events into two distinct categories by introducing dual threshold values: an upper threshold for detecting true X-ray photon events and a lower threshold for identifying and correcting induction-based false events. This segmentation allows the system to process and correct different types of signals separately, enabling filtering of induction events without sacrificing low-energy photon detection capability.
Solution Approach 2:
The patent changes the parameter of threshold values from a single value to two distinct values (upper and lower thresholds). By establishing an upper threshold above the reference value for true event detection and a lower threshold below the reference value for induction event detection, the system can differentiate between genuine X-ray photon signals and induction-based false signals, thereby improving image contrast while maintaining sensitivity to low-energy photons.
2Measurement precision
If quantum-counting X-ray detectors are used to achieve high spatial resolution and contrast, then detection capability is improved, but induction-based counting events from adjacent pixels worsen image quality
Solution Approach 1:
The patent implements a feedback mechanism where the lower threshold detection of induction-based events generates correction signals that are used to adjust and correct the upper threshold counting results. This feedback loop allows the system to identify false events caused by induction and systematically correct them, thereby maintaining the high spatial resolution and contrast capabilities of quantum-counting detectors while eliminating the harmful induction-based counting events.
Solution Approach 2:
The patent converts the harmful induction-based counting events into a beneficial correction mechanism. By using the lower threshold to detect induction events and generate correction signals, the system transforms what was previously a source of image degradation into a useful tool for improving image quality. The induction events, rather than merely being filtered out, actively provide information that corrects the main counting results.
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 enhances image contrast by accurately distinguishing between X-ray photon-generated and induction-based signals, allowing for better detection of low-energy photons and maintaining high spatial resolution while minimizing noise.
Implementation Method 1
an incident X-ray photon initially generates a free electron in a semiconductor, for example cadmium telluride, by ionization of one of the lattice atoms
Implementation Method 2
an incident X-ray photon initially generates a free electron in a semiconductor, for example cadmium telluride, by ionization of one of the lattice atoms
Implementation Method 3
Due to the effects of mirror charges, however, an X-ray photon especially in the boundary region of two detector pixels can lead, through induction to a current pulse or a voltage pulse in the adjacent pixel
Data Source
AI summary
A method and an X-ray detector are for correcting a spatially resolved photon scan of the X-ray detector. In an embodiment, the X-ray detector includes processing circuitry configured to: generate, from an incident X-ray photon, a signal contribution in a first electrical signal in a spatially resolved manner, a reference value being defined by an absence of X-ray photons; resolve, in relation to the reference value, positive signal contributions of the first electrical signal and negative signal contributions of the first electrical signal; and provide the positive signal contributions resolved and the negative signal contributions resolved for further processing.