X-ray Photon Discriminator Assembly for Spectral Classification
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Solution Overview
Problem
Conventional x-ray or CT imaging systems using scintillator or direct-conversion detectors in current-integration mode cannot discriminate between the energy level and photon count of individual photons, especially when multiple photons of different energies are detected, leading to inadequate data feedback and increased complexity and cost with the need for multiple hardware energy bins.
Innovation Solution
Implementing a discriminator assembly in the data acquisition system that alternates between two threshold levels during successive x-ray views, allowing for the classification of photon hits into a greater number of energy bins than the number of hardware discriminator channels by modifying photon counts based on energy levels, effectively transforming data into additional bins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If multiple hardware energy bins are used to classify photons into more energy levels, then spectral information increases, but device complexity and cost increase
Solution Approach 1:
The patent applies periodic action by alternating between two different threshold levels during successive x-ray views. The discriminator assembly switches between a first threshold level during odd views and a second threshold level during even views, allowing classification of photons into multiple energy bins using only two hardware channels. This temporal multiplexing approach enables spectral information equivalent to multiple hardware bins while using minimal hardware.
Solution Approach 2:
The patent uses data processing to create virtual copies of hardware discriminator channels. By collecting photon count data at two different threshold levels and using mathematical operations to solve simultaneous equations, the system generates multiple energy bin classifications that are computational copies of what would require multiple physical discriminator channels, thereby reducing hardware complexity while maintaining spectral information.
2Speed
If current-integration mode is used for detector operation, then detection speed is maintained, but ability to discriminate photon energy levels is lost
Solution Approach 1:
The patent introduces threshold levels as intermediaries between the detector and the photon classification process. By setting specific energy thresholds and counting photons that exceed these thresholds, the system enables energy level discrimination without requiring the detector itself to measure individual photon energies. The threshold levels act as mediators that transform the continuous energy spectrum into discrete countable categories, maintaining fast detection while achieving energy discrimination.
Solution Approach 2:
The patent replaces the need for complex energy-resolving detector mechanics with a simpler threshold-based counting system. Instead of using detectors capable of directly measuring and resolving individual photon energy values, the system uses multiple threshold levels with simple photon counters, substituting a mechanical/physical energy measurement system with a computational threshold-crossing approach that achieves the same discrimination goal.
3Loss of information
If photon counting mode is used with multiple energy bins, then spectral information increases, but data acquisition system complexity increases
Solution Approach 1:
The patent applies dynamics by making the threshold levels variable and switchable rather than fixed. The data acquisition system dynamically changes which threshold level is active during different views, allowing the same hardware to perform multiple classification functions. This dynamic switching enables the system to adapt its classification scheme without adding permanent hardware for each energy bin, reducing overall system complexity while maintaining full spectral information capability.
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 the spectral information of the x-ray beam by allowing classification into more energy bins than hardware channels, reducing system complexity and cost while maintaining detailed photon data, thereby improving image reconstruction accuracy.
Implementation Method 1
the detector includes direct conversion detector cells for converting x-rays directly to electrical signals indicative of the amount of energy in the x-rays
Implementation Method 2
the detector includes scintillator detector cells for converting x-rays to light energy and photodiodes for receiving the light energy from the adjacent scintillator and producing electrical signals therefrom
Implementation Method 3
a discriminator assembly configured to count photon hits in the detector that occur at photon energies greater than or equal to a threshold level
Data Source
AI summary
A system and apparatus for classifying x-ray energy into discrete levels include an imaging system comprising an x-ray source, a detector, and a DAS having a discriminator assembly configured to count photon hits in the detector. A computer causes the discriminator assembly to count photon hits in the detector having an energy level greater than or equal to first and second threshold levels during an imaging scan, wherein the second threshold level is distinct from the first threshold level. The computer further modifies the counted photon hits having an energy level greater than or equal to the first threshold level based on the counted photon hits having an energy level greater than or equal to the second threshold level and reconstructs an image based on the modified photon hits and based on the counted photon hits having an energy level greater than or equal to a second threshold level.