Photon-Counting Detector Pile-Up Correction via Energy Intensity

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Solution Overview

Problem

Energy-discriminating, photon-counting detectors in multi-energy X-ray imaging systems face limitations due to high incident photon flux rates, leading to pile-up effects that result in spectral distortions and errors in material decomposition, particularly in clinical CT imaging.

Innovation Solution

The system employs an energy-discriminating, photon-counting X-ray detector with data processing circuitry to simulate count rates for each energy bin using a detector pile-up model, generating energy intensity-dependent material decomposition vectors for accurate material decomposition, even at high photon flux rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an energy-discriminating, photon-counting detector is used to achieve energy discrimination and material decomposition capability, then the ability to perform multi-energy imaging is improved, but the detector cannot keep pace with high incident photon flux rates, causing pile-up effects and spectral distortions

Engineering Contradiction:
Improveenergy discrimination capabilityVSAvoiddetector accuracy at high flux rates
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary actions by measuring the total energy signal and using it to generate correction factors before the material decomposition process. The pile-up correction is applied in advance to the projection data, allowing the detector to accurately represent high flux rates without spectral distortions affecting the final material decomposition results

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the total energy signal to correct the measured photon counts. By continuously monitoring the energy signal and comparing it with the expected signal based on incident flux rate, the system generates correction factors that feedback into the material decomposition process, eliminating pile-up effects and improving detector reliability at high flux rates

Inventive Principle:
Principle #23Feedback

2Productivity

If the incident photon flux rate is increased to improve imaging speed and productivity, then clinical CT imaging requirements are met, but pile-up effects cause dramatic distortions in the detected signal and errors in material decomposition

Engineering Contradiction:
Improveimaging speedVSAvoidmaterial decomposition accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system changes the parameter approach by introducing energy intensity as a weighting factor in the material decomposition process. Instead of using fixed decomposition vectors, the system dynamically adjusts the decomposition vectors based on the measured energy intensity and corresponding pile-up correction factors, allowing accurate material decomposition even at high photon flux rates where pile-up occurs

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional pile-up correction methods are used that do not account for material decomposition requirements, then pile-up effects are partially addressed, but the need to perform accurate material decomposition in multi-energy imaging is not met

Engineering Contradiction:
Improvepile-up correctionVSAvoidmaterial decomposition capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system merges the pile-up correction process with the material decomposition process into a unified approach. The correction factors derived from the total energy signal are integrated into the material decomposition algorithm, combining what were previously separate correction steps into a single cohesive process that simultaneously achieves pile-up correction and accurate material decomposition

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system creates a universal material decomposition framework that works across different energy spectra and pile-up conditions. The decomposition vectors are generated to be universally applicable by incorporating the energy intensity-dependent correction factors, allowing the same decomposition process to accurately handle both pile-up corrected and uncorrected data across various imaging conditions

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 effectively corrects for pile-up effects and improves the accuracy of material decomposition in multi-energy CT imaging, reducing artifacts and maintaining computational efficiency, making it a cost-effective solution for existing systems.

Implementation Method 1

the underlying physical effects of X-ray interaction with matter are considered, namely, the Compton scattering effects and photoelectric effects

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

the underlying physical effects of X-ray interaction with matter are considered, namely, the Compton scattering effects and photoelectric effects

Methodology Applied
Scientific EffectCompton scattering: Compton Scattering

Implementation Method 3

a signal representing the total energy deposited during the data acquisition time period

Methodology Applied
Scientific EffectEnergy deposition: Absorption (EM radiation)

Data Source

PatentUS9220469B2Systems and methods for correcting detector errors in computed tomography imaging
Publication Date: 2015.12.29 GE PRECISION HEALTHCARE LLC
  • US9220469B2 patent drawing
  • US9220469B2 patent drawing
  • US9220469B2 patent drawing

AI summary

A system includes an energy-discriminating, photon-counting X-ray detector, comprising a plurality of detector cells adapted to produce projection data in response to X-ray photons and to produce an electrical signal having a recorded count for the energy bins and a total energy intensity. The system also includes data processing circuitry adapted to receive the electrical signal, to generate a simulated count rate for each of the energy bins by using the total energy intensity, to determine a set of energy intensity dependent material decomposition vectors, and, for the measured projection data, to perform material decomposition.