Counting X-Ray Detector Coincidence Estimation With Temporal Offset
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Solution Overview
Problem
Photon-counting X-ray detectors face issues with spatial and energy resolution due to true coincidences, where the energy of an X-ray quantum is distributed across multiple detector elements, leading to overestimation of coincidences and reduced accuracy.
Innovation Solution
A method to estimate the rate of random coincidences by using a coincidence unit with non-adjacent signal inputs and temporal offset, allowing for precise differentiation between true and random coincidences, thereby improving the accuracy of coincidence counting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If coincidence counters are used to detect true coincidences, then spatial resolution is improved, but random coincidences cause overestimation and reduce measurement precision
Solution Approach 1:
The patent segments the coincidence detection process into two independent parts: a first coincidence counter for detecting true coincidences and a second coincidence counter for detecting random coincidences. By separating the detection of true coincidences and random coincidences into distinct counting channels, the system can independently measure and subsequently subtract random coincidences from the total count, thereby eliminating the overestimation problem while maintaining spatial resolution benefits
Solution Approach 2:
The patent introduces a temporal offset as an intermediary mechanism between the two coincidence counters. The first coincidence counter operates without temporal offset to detect all coincidences, while the second coincidence counter applies a temporal offset to detect only random coincidences. This temporal offset acts as a mediator that enables selective detection of random coincidences without affecting the detection of true coincidences in the first counter
2Manufacturing precision
If detector elements are made smaller to improve spatial resolution, then spatial resolution is improved, but charge distribution across multiple pixels increases true coincidences
Solution Approach 1:
The patent implements a feedback mechanism where the output of the second coincidence counter (random coincidences) is fed back to correct the output of the first coincidence counter (true coincidences). By continuously measuring random coincidences and subtracting them from the total coincidence count, the system compensates for the increased coincidence frequency caused by smaller detector elements, thereby maintaining accurate measurement despite higher coincidence rates
3Productivity
If photon flux is increased to improve productivity, then measurement speed is improved, but random coincidences increase and reduce measurement precision
Solution Approach 1:
The patent applies preliminary action by measuring and characterizing random coincidences before they contaminate the true coincidence measurements. The second coincidence counter with temporal offset预先 identifies the random coincidence rate at the current photon flux level, allowing the system to pre-calculate the correction factor that will be applied to the first coincidence counter's output, thereby maintaining accuracy even at high measurement speeds
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 method enhances the accuracy of coincidence counting, enabling extended usable ranges for higher X-ray fluxes and reducing overcorrection, thus improving spatial and energy resolution in photon-counting detectors.
Implementation Method 1
Photon-counting X-ray detectors are typically based on a converter converting incoming X-ray signals or X-ray photons into electrical signals
Data Source
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AI summary
A method for estimating a rate of random coincidences in a counting X-ray detector (31) having a plurality of detector elements, the method comprising the following steps: - detecting X-ray signals by the X-ray detector (31) and converting the X-ray signals into electrical signals;- forwarding at least some of the electrical signals to signal inputs of a coincidence unit (2), wherein the signal inputs comprise a first signal input and at least one further signal input, - wherein the signals for the first signal input are detected in a first of the detector elements, - wherein the signals for the at least one further signal input are each detected in a different detector element not directly adjacent to the first of the detector elements and/or wherein signals for the at least one further signal input or the signals for the first signal input are temporally offset in an electrical circuit with a defined time interval; - counting coincidences of the signals forwarded to the coincidence unit (2) and estimating a rate of random coincidences;