Photon-Counting CT Projection Correction for Spectral Accuracy

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Solution Overview

Problem

Existing CT imaging technologies face challenges in achieving high spatial resolution, low electronic noise, and accurate spectral decomposition, particularly in photon-counting computed tomography (PCCT), which affects image quality and radiation dose efficiency.

Innovation Solution

A method and system for CT imaging that includes air correction, basis material decomposition, and optimization correction using a Photon-Counting detector, employing a response model and optimization parameter to enhance image quality by correcting projection data in the projection domain, thereby improving material quantification and reducing artifacts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional CT imaging is used, then the imaging process is simple, but spatial resolution and spectral decomposition accuracy are insufficient

Engineering Contradiction:
Improvespatial resolutionVSAvoidimaging process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the imaging process into distinct correction steps: air correction using an air correction table, basis material decomposition, and optimization correction using a response model. Each segment addresses specific sources of error independently, improving spatial resolution and spectral decomposition accuracy without overwhelming system complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary corrections in the projection domain before image reconstruction. The air correction table and response model are pre-computed and applied to projection data early in the pipeline, preventing error propagation to later stages and enabling high-resolution imaging with manageable complexity

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If Photon-Counting detector is used, then spectral decomposition accuracy improves, but electronic noise and radiation dose become critical issues

Engineering Contradiction:
Improvespectral decomposition accuracyVSAvoidelectronic noise and radiation dose
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback through the optimization correction step, where the response model uses system calibration data to refine the projection data. This feedback loop compensates for electronic noise and optimizes the spectral decomposition accuracy while minimizing the required radiation dose

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes key parameters including the introduction of an air correction table and response model parameters derived from system calibration. These parameter transformations enable the Photon-Counting detector to achieve high spectral decomposition accuracy while managing electronic noise and radiation dose through optimized correction algorithms

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If air correction and optimization correction are performed, then image quality improves, but processing time and computational complexity increase

Engineering Contradiction:
Improveimage qualityVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs computationally intensive corrections in the projection domain before reconstruction, rather than after. The air correction table and response model optimizations are pre-computed from calibration data, reducing real-time processing requirements and minimizing loss of time while maintaining high image quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses calibration data to create corrected versions of projection data through the response model. This copying approach allows pre-computed correction factors to be applied efficiently, reducing computational burden during actual imaging while maintaining high image quality through multiple correction passes

Inventive Principle:
Principle #26Copying

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 and system achieve higher quality medical images with improved spatial resolution, lower electronic noise, and more accurate spectral decomposition, enhancing the overall image quality and reducing radiation dose.

Implementation Method 1

Photon-Counting computed tomography (PCCT) has gradually become one of the important development directions of CT technology

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

obtaining scanning data of a target subject, the scanning data being acquired by scanning the target subject using a CT device

Methodology Applied
Scientific EffectX-Ray: X-Ray

Data Source

PatentEP4609793A1Methods and systems for computed tomography (CT) imaging
Publication Date: 2025.09.03 SHANGHAI UNITED IMAGING HEALTHCARE
  • EP4609793A1 patent drawingFigure 1
  • EP4609793A1 patent drawingFigure 2
  • EP4609793A1 patent drawingFigure 3~4

AI summary

The embodiments of the present disclosure provide a method and system for computed tomography (CT) imaging. The CT imaging method comprises: obtaining scanning data of a target subject, the scanning data being acquired by scanning the target subject using a CT device; determining data after air correction by performing air correction on the scanning data using an air correction table; determining projection data of at least two standard materials by performing basis material decomposition on the data after air correction; and generating a target image based on the projection data of the at least two standard materials.