Photon-Counting CT Threshold Switching for Single-Scan Spectral Imaging

Solution Overview

Problem

Spectral CT systems with limited comparators and counters per pixel are ill-suited for applications requiring multiple energy thresholds, leading to poor time-domain alignment of energy bin information and motion artifacts due to multi-rotation scanning, which also increases radiation dose.

Innovation Solution

A scanning method for a CT device with a photon counting detector that adjusts the threshold voltage of threshold comparators sequentially to multiple energy thresholds using trigger signals, allowing simultaneous acquisition of energy bin information across these thresholds in a single scan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multi-rotation scanning is used to acquire energy bin information across multiple energy thresholds, then the spectral CT system can obtain energy bin information at multiple thresholds, but poor time-domain alignment of energy bin information results, leading to motion artifacts and additional radiation dose

Engineering Contradiction:

Improveenergy threshold coverageVSAvoidtime-domain alignment

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent dynamically adjusts the threshold voltage of the comparator during a single scan rotation by applying different offset voltages to the reference voltage input of the comparator. This allows the energy threshold to be varied continuously or in discrete steps while maintaining synchronization with the detector's readout timing, thereby achieving multi-energy-threshold capability without requiring multiple rotations and preserving time-domain alignment.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If multi-rotation scanning is used to acquire energy bin information across multiple energy thresholds, then the spectral CT system can obtain energy bin information at multiple thresholds, but motion artifacts occur due to temporal interval between acquisitions

Engineering Contradiction:

Improveenergy threshold coverageVSAvoidmotion artifacts

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent dynamically adjusts the threshold voltage of the comparator during a single scan rotation by applying different offset voltages to the reference voltage input of the comparator. This allows the energy threshold to be varied continuously or in discrete steps while maintaining synchronization with the detector's readout timing, thereby achieving multi-energy-threshold capability without requiring multiple rotations and preserving time-domain alignment.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If multi-rotation scanning is used to acquire energy bin information across multiple energy thresholds, then the spectral CT system can obtain energy bin information at multiple thresholds, but additional radiation dose is incurred

Engineering Contradiction:

Improveenergy threshold coverageVSAvoidradiation dose

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The patent dynamically adjusts the threshold voltage of the comparator during a single scan rotation by applying different offset voltages to the reference voltage input of the comparator. This allows the energy threshold to be varied continuously or in discrete steps while maintaining synchronization with the detector's readout timing, thereby achieving multi-energy-threshold capability without requiring multiple rotations and preserving time-domain alignment.

Inventive Principle:

Principle #15Dynamics

4Device complexity

If limited comparators and counters are used per pixel, then design and integration complexity is reduced and costs are lowered, but the system is ill-suited for applications requiring multiple energy thresholds

Engineering Contradiction:

Improvecomparator and counter quantityVSAvoidenergy threshold capability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent changes the operating parameter (threshold voltage) of the existing comparator dynamically by adding an adjustable offset voltage to its reference input. This allows a single comparator to effectively perform multiple energy threshold comparisons that would otherwise require multiple comparators, thereby maintaining low device complexity while achieving multi-energy-threshold capability for applications like K-edge imaging and multi-material discrimination.

Inventive Principle:

Principle #35Parameter changes

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

Improves time-domain matching of energy bin information, reducing motion artifacts and radiation dose by enabling simultaneous acquisition of energy bin information at multiple thresholds, thereby enhancing image reconstruction quality.

Implementation Method 1

a threshold voltage of at least one threshold comparator disposed in the photon counting detector is adjusted to a voltage corresponding to each of the multiple sets of energy thresholds

Methodology Applied

Scientific EffectVoltage comparison:

Data Source

PatentUS20250383461A1Scanning method for CT device, photon counting detector, and energy spectrum CT system

Publication Date: 2025.12.18 WUHAN UNITED IMAGING LIFE SCIENCE INSTRUMENT CO LTD

AI summary

This disclosure relates to the field of X-ray based medical imaging technology, providing a method, device, and CT scanning imaging system for spectral CT imaging, which may improve the efficiency of reconstructed images. In this disclosure, after obtaining multiple data frames collected by the detector, each data frame is cached in energy segments and stored in memory; Read the data frames required for image reconstruction from memory or disk; Obtain reconstructed images using the read data frames.