Radiation Image Processing Using PSF Deconvolution for Scintillator Blurring

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Solution Overview

Problem

Indirect radiation detectors using scintillator panels suffer from blurring due to light scattering, which reduces the sharpness of radiation images and is not effectively addressed by existing methods, leading to lower image quality.

Innovation Solution

A radiation image processing method that involves obtaining a radiation image using an indirect radiation detector with a scintillator panel and a pixel array panel, determining a point spread function (PSF) parameter value, and deconvoluting the image using this PSF to correct blurring, while ensuring image quality references such as DQE and MTF are maintained.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If an indirect radiation detector using a scintillator panel is used, then the radiation image can be obtained through conversion of radiation to visible light, but light scattering occurs in the scintillator panel causing blurring and reduced sharpness

Engineering Contradiction:
Improveradiation to light conversion efficiencyVSAvoidimage sharpness
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent introduces a light guide layer as an intermediary component between the scintillator panel and the pixel array. This light guide layer with a refractive index higher than both the scintillator and the pixel array serves as a mediator to control light propagation, reducing light scattering and improving image sharpness while maintaining the radiation-to-light conversion efficiency of the scintillator panel

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the refractive index parameter of the light guide layer to be higher than both the scintillator panel and the pixel array. This parameter change optimizes light propagation characteristics, reducing light scattering and improving image sharpness without compromising the radiation conversion efficiency

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the scintillator panel thickness is increased to improve radiation detection efficiency, then more radiation photons are converted to visible light, but light scattering increases causing more severe blurring

Engineering Contradiction:
Improveradiation detection efficiencyVSAvoidimage sharpness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The light guide layer acts as a mediator that becomes increasingly important as scintillator thickness increases. It controls and directs the light photons generated in the thicker scintillator panel, preventing excessive scattering and maintaining image sharpness even when detection efficiency is improved through increased thickness

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If conventional scatter radiation removal methods (anti-scatter grid or air gap) are used, then scatter radiation from the subject is reduced, but scattering by the scintillator inside the radiation detector is not removed

Engineering Contradiction:
Improvescatter radiation from subjectVSAvoidscintillator internal scattering
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The light guide layer serves as an internal intermediary within the detector that addresses scintillator internal scattering. By positioning this layer between the scintillator and pixel array with optimized refractive index, it controls light propagation from the scintillator, reducing internal scattering effects that conventional external methods cannot address

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical scatter radiation removal methods (anti-scatter grid or air gap) with an optical solution using a light guide layer. This substitution addresses the remaining scintillator internal scattering problem that mechanical methods cannot solve, as the light guide layer directly manages light propagation within the detector

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method improves the sharpness of radiation images by effectively correcting blurring caused by scintillator panel scattering, maintaining high detective quantum efficiency (DQE) and modulation transfer function (MTF), and reducing radiation exposure dose, while preventing artificial enhancement of image features.

Implementation Method 1

a radiation collides with a scintillator of a scintillator panel to generate a visible light ray

Methodology Applied
Scientific EffectScintillation: Scintillation

Implementation Method 2

the visible light ray is transformed to an image signal through a thin film transistor in which a charge coupled device (CCD) or a photodiode is installed

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

scattering by the scintillator inside the radiation detector is not removed. In addition, when a radiation image is obtained by this radiographic system, a blurring may occur in the radiation image

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP3342342B1Radiation image processing method and radiographic system
Publication Date: 2020.12.09 DRTECH CORP
  • EP3342342B1 patent drawingFigure 1~2
  • EP3342342B1 patent drawingFigure 3~4
  • EP3342342B1 patent drawingFigure 5~6

AI summary

Provided is a radiation image processing method including obtaining a radiation image using an indirect radiation detector comprising a scintillator panel and a pixel array panel, determining a parameter value for defining a point spread function (PSF) according to the scintillator panel or the pixel array panel, and correcting the radiation image by deconvoluting the radiation image using the PSF to which the parameter value is applied.