X-ray Opaque Markers for Compression Paddle Deflection

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Solution Overview

Problem

Current mammography systems face imprecision in breast density assessment due to uncertainties in compression thickness measurement, particularly caused by paddle deflection and tilt, leading to significant misjudgments in breast density estimation.

Innovation Solution

Incorporating X-ray opaque marker elements into the compression paddle, which are detected in X-ray images to determine the geometrical alteration of the compression element, allowing for precise calculation of the compression height and accounting for deflections and tilts, thereby improving the accuracy of breast density assessment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If compression thickness is measured at the object distal side where compression force is applied, then the measurement process is simple, but the measurement precision deteriorates due to paddle deflection and tilt causing errors up to 15 mm

Engineering Contradiction:
Improvemeasurement process simplicityVSAvoidcompression thickness measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces X-ray opaque marker elements as intermediary reference objects attached to the compression paddle. These markers serve as mediators between the measurement system and the compression paddle, allowing indirect measurement of the paddle's position and orientation. By tracking the markers' positions in X-ray images, the system can calculate the paddle's deflection and tilt, thereby compensating for measurement errors without changing the simple compression procedure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical measurement of compression thickness with an image-based optical measurement system. Instead of using mechanical sensors that would require complex integration, the system uses X-ray imaging to detect marker positions and computationally determine compression parameters. This substitution of mechanical measurement with optical/image-based measurement achieves higher precision while maintaining operational simplicity.

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

2Measurement precision

If marker elements are incorporated into the compression paddle to track geometrical alteration, then the measurement precision improves to sub-pixel accuracy, but the device complexity increases due to additional components and processing

Engineering Contradiction:
Improvecompression height determination accuracyVSAvoidsystem structural complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the measurement parameter from direct physical distance measurement to indirect coordinate-based calculation. By measuring the positions of marker elements in the X-ray image coordinate system and calculating compression height through geometric relationships, the system achieves sub-pixel accuracy. This parameter transformation allows precise measurement without requiring complex mechanical measurement devices.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a digital copy or model of the compression paddle's geometrical state by tracking marker positions. Instead of directly measuring the complex three-dimensional deformation of the paddle, the system creates a simplified representation using marker coordinates and calculates the necessary parameters from this digital model. This copying approach reduces measurement complexity while maintaining precision.

Inventive Principle:
Principle #26Copying

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 achieves sub-pixel accuracy in determining the compression height, reducing errors to less than 0.5 mm, and significantly enhances the precision of breast density assessment by accounting for the altered geometry of the compression element during imaging.

Implementation Method 1

Incorporating X-ray opaque marker elements into the compression paddle, which are detected in X-ray images to determine the geometrical alteration of the compression element

Methodology Applied
Scientific EffectX-ray attenuation: Absorption (EM radiation)

Data Source

PatentEP2744411B1Image-based determination of compression element deflection
Publication Date: 2020.03.18 PHILIPS GMBH
  • EP2744411B1 patent drawingFigure 1
  • EP2744411B1 patent drawingFigure 2
  • EP2744411B1 patent drawingFigure 3

AI summary

The invention relates to X-ray imaging technology as well as image post- processing and analyzing. An X-ray imaging system element (3), an X-ray imaging system (2), the use of a system element in an X-ray imaging system and the method (40) of determining a deflection of a compression element is disclosed. The X-ray imaging system element (3) comprises two compression elements (8a, 8b), which are movable relative to one another. An object (10) is introducible and compressible between the compression elements. At least one of the compression elements is adapted to alter its geometrical shape and/or alignment relative to the other during compression. At least one partly X-ray opaque marker element (24) is provided on one of the compression elements, which marker element is adapted to allow detection of an alteration of the geometrical shape of the respective compression element (8a, b).