X-ray Detector Thermal Gain Correction Lookup Table

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Solution Overview

Problem

Current CT detectors face challenges in maintaining consistent thermal gain due to temperature variations, leading to ring artifacts and image quality issues, as they require tight thermal control and calibration across multiple channels.

Innovation Solution

A method involving the creation of a lookup table for thermal correction on a pixel-by-pixel basis, using a single diode to measure temperature and store it for later correction, and implementing a DAS-based thermal gain correction scheme to account for temperature drift, allowing for forward and reverse biasing of diodes for accurate temperature measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If tight thermal control is implemented on the detector, then thermal gain stability is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvethermal gain stabilityVSAvoidthermal control system complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent uses the detector diodes themselves to measure temperature, eliminating the need for separate temperature sensors. Each diode serves dual purposes: detecting x-rays and measuring temperature through its electrical characteristics, thereby reducing system complexity while maintaining thermal gain stability

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent measures temperature by monitoring changes in diode electrical parameters (current or voltage) in response to temperature variations. By establishing a relationship between diode electrical characteristics and temperature, the system achieves thermal monitoring without additional hardware, reducing complexity while maintaining stability

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If multiple temperature sensors are used for accurate temperature measurement, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improvetemperature measurement precisionVSAvoiddetector structure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the detector diodes multi-functional by using them both for x-ray detection and temperature measurement. The same diode structure serves dual purposes, eliminating the need for separate temperature sensors and reducing overall device complexity while maintaining measurement precision

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The detector diodes self-measure their own temperature through their electrical characteristics without requiring external temperature sensors. This self-service approach reduces component count and simplifies the detector structure while achieving accurate temperature measurement

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If thermal calibration is performed on a pixel-by-pixel basis, then manufacturing precision is improved, but time and resource consumption increase

Engineering Contradiction:

Improvethermal correction precisionVSAvoidcalibration time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent performs thermal calibration measurements during the detector manufacturing process before the detector is installed in the CT scanner. By completing the pixel-by-pixel thermal characterization in advance and storing the data in lookup tables, the system achieves high manufacturing precision without adding calibration time to the clinical workflow

Inventive Principle:

Principle #10Preliminary action

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 enables accurate thermal management relaxation, reduces warm-up time, corrects gain drift due to thermal variations, and improves image quality by compensating for temperature-induced changes, while also reducing component costs and process complexities.

Implementation Method 1

The thermal gain temperature coefficient drift in the module may have multiple root causes: a) diode, b) collimator, c) scintillator, d) DAS electronics and finally e) DAS assembly

Methodology Applied

Scientific EffectTemperature coefficient drift:

Implementation Method 2

Current CT detectors generally use scintillation crystal/photodiode arrays, where the scintillation crystal absorbs x-rays and converts the absorbed energy into visible light

Methodology Applied

Scientific EffectScintillation: Scintillation