Tomosynthesis Marker Artifact Removal via Extraction

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Solution Overview

Problem

Intraoral tomosynthesis imaging faces challenges with spatial instability and marker artifacts, leading to degraded image quality and spatial resolution due to motion and the obscuration of anatomical details by radiopaque markers, which are difficult to place without compromising image quality.

Innovation Solution

The use of an aiming ring with strategically placed markers that are designed to minimize their presence in the projection images, allowing for accurate alignment and subsequent removal of marker artifacts through image processing techniques, thereby improving the quality and spatial resolution of reconstructed tomosynthesis images.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If radiopaque markers are placed within the field of view to facilitate alignment of projection images, then alignment accuracy is improved, but image quality deteriorates due to obscuration of anatomical detail and creation of reconstruction artifacts

Engineering Contradiction:
Improvealignment accuracyVSAvoidmarker artifacts and anatomical obscuration
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent extracts and removes the harmful marker artifacts from the projection images through image processing techniques. The system identifies marker locations and applies processing to eliminate the high-contrast edges and streaking artifacts while preserving the alignment information needed for reconstruction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful high-contrast marker signals into useful alignment information. By processing the marker-containing images to extract geometric transformation parameters, the system uses the markers' strong contrast (which causes artifacts) as reliable alignment features, then removes the markers' harmful effects in the processed images.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of operation

If the field of view is reduced to fit intraoral imaging constraints, then device compactness and ease of operation are improved, but image quality worsens due to significant blurring along depth directions

Engineering Contradiction:
Improvechair-side imaging convenienceVSAvoidspatial resolution and depth information
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent applies dynamic alignment techniques that adapt to the specific geometric transformations present in each projection image. Rather than using a fixed geometric model, the system dynamically determines transformation parameters by comparing marker positions across multiple projections, allowing accurate alignment even with limited scan angles and small fields of view.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter space by working with geometric transformation parameters (rotation, translation, scaling) derived from marker positions rather than assuming fixed geometric relationships. This allows the system to accommodate variations in detector positioning and patient anatomy while maintaining alignment accuracy despite the limited angular range.

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 enables reliable, artifact-free alignment of projection images, enhancing the data quality and spatial resolution of reconstructed tomosynthesis images, reducing the impact of marker artifacts and maintaining image contrast and detail.

Implementation Method 1

X-ray radiography can be performed by positioning an x-ray source on one side of an object (e.g., a patient or a portion thereof) and causing the x-ray source to emit x-rays through the object and toward an x-ray detector

Methodology Applied
Scientific EffectX-ray attenuation: X-Ray

Data Source

PatentEP3253293B1Methods and systems for removing artifacts from a tomosynthesis dataset
Publication Date: 2022.06.08 SIRONA DENTAL INC
  • EP3253293B1 patent drawingFigure 1A
  • EP3253293B1 patent drawingFigure 1B
  • EP3253293B1 patent drawingFigure 1C

AI summary

Method, system, apparatus, and computer program products for removing marker artifacts from a tomosynthesis dataset. In the method, a first plurality of projection images are acquired by tomosynthesis x-ray imaging, the first plurality of projection images containing at least one imaged representation of at least one alignment marker. In one aspect, the imaged representation of the at least one alignment marker on the first plurality of projection images is minimized to generate a second plurality of projection images. In another aspect, a plurality of tomographic images are reconstructed from the second plurality of projection images.