Photon Counting Detector Calibration With Representative Difference Signals
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Solution Overview
Problem
The high nonlinearity of photon counting detectors in photon counting computed tomography (PCCT) systems makes it difficult to model and manage the vast amount of calibration data required for accurate imaging, especially considering various imaging, subject, and environmental conditions.
Innovation Solution
A calibration apparatus and method that derives a representative detection signal and a difference signal from the photon counting detector's detection elements, reducing the data amount by storing these signals in a database for each detection element group, rather than individual signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration data is acquired for each detection element under various imaging conditions, then measurement precision is improved, but data volume increases significantly
Solution Approach 1:
The patent segments the calibration data into two components: representative detection signals (one per detection element group) and difference signals (for each individual detection element within the group). This segmentation allows storing only essential reference data while using difference signals to represent individual variations, significantly reducing the overall data volume while maintaining calibration precision.
Solution Approach 2:
The patent transforms the calibration data representation by changing from storing complete individual detection signals to storing difference signals relative to representative signals. This parameter transformation reduces data redundancy while preserving the necessary information for accurate calibration correction.
2Reliability
If calibration data is stored for each detection element, then reliability is improved, but device complexity increases
Solution Approach 1:
By dividing detection elements into groups and segmenting calibration data into representative signals and difference signals, the patent reduces data management complexity while maintaining reliability. The segmented structure allows for more efficient storage and retrieval operations compared to managing complete individual signals for all detection elements.
Solution Approach 2:
The patent uses representative detection signals as templates or copies that represent entire detection element groups. Individual detection elements are calibrated by applying difference signals to these representative copies, reducing the need to store and manage complete calibration data for each individual element while maintaining calibration reliability.
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 significantly reduces the data capacity of calibration data, allowing for efficient modeling and management of calibration data, even with nonlinearity, by using representative signals and difference signals.
Implementation Method 1
In the photon counting detector, in a case in which an X-ray photon is incident on a detection element included in the detector, a detection signal corresponding to the number of counts of the incident photons is output
Data Source
AI summary
Calibration data of a photon counting detector consisting of a plurality of detection elements that output detection signals corresponding to photon energies of incident radiation is acquired. A processor is configured to: acquire a plurality of detection signals output from the plurality of detection elements of the photon counting detector in accordance with a predetermined acquisition condition; derive a difference signal representing a difference between at least one representative detection signal that is representative of the plurality of detection signals and the plurality of detection signals; and store the at least one representative detection signal and the difference signal, as calibration data in accordance with the acquisition condition.