Radiation Imaging Noise Control via Adaptive Energy Subtraction

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Solution Overview

Problem

Existing radiation imaging apparatuses face challenges in achieving high-quality energy subtraction images due to differing noise amounts in high-energy and low-energy radiation images, which affect the quality of the energy subtraction image.

Innovation Solution

A radiation imaging apparatus that adjusts radiation irradiation conditions based on noise amounts in high-energy and low-energy images, using equations to optimize the ratio of noise values and control exposure to minimize noise in the energy subtraction image, ensuring the noise ratio falls within a specific range to enhance image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the time over which low-energy radiation is generated is increased to equalize the counts of detected radiations, then the count of low-energy radiation detected is improved, but the noise amount in the low-energy radiation image increases

Engineering Contradiction:
Improvecount of detected radiationVSAvoidnoise amount in image
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by adjusting the radiation generation time based on the object's thickness. For thick objects, the low-energy radiation generation time is extended to equalize detection counts between high and low energy radiations. For thin objects, the time is reduced to minimize noise. This dynamic parameter adjustment resolves the contradiction between achieving sufficient count equalization and minimizing noise accumulation.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the radiation generation time is extended to equalize detection counts for thick objects, then the detection count equality is improved, but the noise amount in the energy subtraction image increases

Engineering Contradiction:
Improveequality of detection countsVSAvoidnoise amount in energy subtraction image
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamics by making the radiation generation time adaptive rather than fixed. The control unit dynamically adjusts the low-energy radiation generation time based on the detected object thickness. This dynamic adjustment allows the system to achieve count equality for thick objects while avoiding excessive noise generation, as the time is optimized for each specific imaging scenario rather than using a uniform extended time for all cases.

Inventive Principle:
Principle #15Dynamics

3Object-affected harmful factors

If the radiation generation time is reduced to minimize noise, then the noise amount in the low-energy radiation image is improved, but the detection count equality deteriorates

Engineering Contradiction:
Improvenoise amount in imageVSAvoidequality of detection counts
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The patent applies parameter changes by adjusting the radiation generation time based on the object's thickness. For thick objects, the low-energy radiation generation time is extended to equalize detection counts between high and low energy radiations. For thin objects, the time is reduced to minimize noise. This dynamic parameter adjustment resolves the contradiction between achieving sufficient count equalization and minimizing noise accumulation.

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

This approach effectively suppresses noise in energy subtraction images, resulting in improved image quality by optimizing radiation irradiation conditions to maintain a controlled noise ratio, thereby enhancing diagnostic capabilities.

Implementation Method 1

a radiation generation unit that generates radiation

Methodology Applied
Scientific EffectX-ray generation: X-Ray

Implementation Method 2

a detection unit that detects the radiation

Methodology Applied
Scientific EffectRadiation detection: Photoelectric Effect

Data Source

PatentEP3662836B1Radiation image pickup device and radiation image pickup system
Publication Date: 2023.11.15 CANON KK
  • EP3662836B1 patent drawingFigure 1
  • EP3662836B1 patent drawingFigure 2~3
  • EP3662836B1 patent drawingFigure 4

AI summary

The present invention provides a radiation imaging apparatus comprising a detection unit configured to generate an image signal according to radiation emitted by a radiation source, an image processing unit, and a control unit. The control unit performs first imaging and second imaging performed after the first imaging using radiations of different energies, the image processing unit generates an energy subtraction image using a first image signal generated by the detection unit in the first imaging and a second image signal generated by the detection unit in the second imaging, and the second imaging is performed under a radiation irradiation condition according to a noise amount included in the first image signal.