X-ray Detector Calibration via Energy Interval Segmentation
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Solution Overview
Problem
Existing X-ray measuring devices face challenges in efficiently correcting beam hardening effects, which lead to image artifacts in CT scans, requiring extensive calibration efforts with multiple test bodies.
Innovation Solution
The method involves preparing the X-ray measuring device to detect energy from incident X-ray photons in multiple intervals, selecting a reference interval with negligible energy dependence, and determining a correction function based on absorption measurements from a test object with known geometry, allowing for calibration that corrects beam hardening with minimal effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple test specimens are used to correct beam hardening, then the correction accuracy is improved, but the calibration effort and complexity increase significantly
Solution Approach 1:
The patent changes the parameter of energy resolution from a continuous spectrum to discrete energy intervals. By dividing the X-ray spectrum into multiple energy intervals and selecting a reference interval with negligible energy dependence, the method transforms the complex multi-specimen calibration into a simplified single-specimen process. The correction function is determined by comparing absorption measurements across different energy intervals, eliminating the need for multiple test specimens with different geometries.
2Reliability
If multiple test specimens with known geometry and thickness are used for calibration, then the beam hardening correction is improved, but the time and effort required for calibration increases
Solution Approach 1:
The patent performs preliminary action by pre-selecting a reference energy interval with negligible energy dependence before the actual calibration measurement. This preliminary selection of the reference interval allows the calibration to proceed with a single test specimen, as the reference interval serves as a built-in reference that eliminates the need for multiple pre-characterized test specimens, thereby reducing calibration time while maintaining reliability.
3Adaptability or versatility
If energy-resolved detection is implemented, then the ability to correct beam hardening is improved, but the device complexity and measurement complexity increase
Solution Approach 1:
The patent applies segmentation by dividing the continuous X-ray energy spectrum into discrete energy intervals. The spectrally sensitive X-ray detector is configured to resolve photons into multiple energy intervals, and a reference interval is selected from these segmented energy ranges. This segmentation approach enables beam hardening correction through energy-comparative measurements while keeping the detector design feasible and the measurement process manageable.
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 enables effective correction of beam hardening effects, reducing the need for multiple test bodies and simplifying the calibration process, while maintaining accurate absorption profile corrections and image quality.
Implementation Method 1
The X-ray measuring device is prepared for a measurement with a resolution of a plurality of different energy intervals such that the energy of incident X-ray photons of an X-ray beam is divided into the individual energy intervals by the X-ray detector
Implementation Method 2
Beam hardening is based on the physical principle that absorption is energy-dependent, meaning that in the X-ray spectrum, higher-energy photons are absorbed to a lesser extent by human tissue or materials with similar optical properties than lower-energy X-ray photons
Data Source
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AI summary
The invention describes a method for calibrating an X-ray measuring device (10) comprising a spectrally sensitive X-ray detector, wherein the X-ray measuring device (10) is prepared for a measurement with a resolution of a plurality of different energy intervals (ΔEj), a test object (16) is positioned in the beam path (14) of an X-ray beam (8), the test object (16) is irradiated by the X-ray beam (8t), and an intensity measurement of the test object (16) is carried out by means of the X-ray measuring device (10) with a resolution corresponding to the energy intervals (ΔEj), an absorption function (a) of the test object (16) is determined on the basis of the intensity measurement of the test object (16), one of the energy intervals (ΔEj) is prepared as a reference interval (ΔER1, ΔER2) such that the absorption function (a) can be determined over the reference interval (ΔER1, ΔER2) exhibits a negligible energy dependence,a correction function of the absorption function (a) for at least one further energy interval is determined based on at least one value of the absorption function (a) in the reference interval (ΔER1, ΔER2), and the X-ray measuring device (10) is calibrated based on the correction function.