Mammography Scatter Correction via Pre-Exposure Mask

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Solution Overview

Problem

Conventional X-ray mammography systems face image degradation due to X-ray scattering, with existing methods either increasing X-ray doses or requiring additional image acquisitions to correct for scattered radiation, which is not feasible for single-image radiography.

Innovation Solution

A method and system that utilize a pre-exposure image with a radio-opaque mask to determine acquisition conditions, allowing for the extraction and correction of X-ray scatter in main images without increasing the X-ray dose or requiring additional images, by using a processing unit to calculate and subtract scattered radiation from the final image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If anti-scatter mechanical grids are used to reduce scattered radiation, then scattered radiation is reduced, but the X-ray dose must be increased to maintain image quality

Engineering Contradiction:

Improvescattered radiationVSAvoidX-ray dose

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The patent replaces the mechanical anti-scatter grid system with a computational method. Instead of using physical grids to block scattered radiation, the system acquires a pre-exposure image with radio-opaque mask elements to measure scatter, then uses image processing to calculate and remove scatter contributions from the final diagnostic image, eliminating the need for mechanical grids and their associated dose increases.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a pre-exposure image acquisition step with radio-opaque mask elements as an intermediary measurement. This intermediate image serves as a proxy to quantify scattered radiation without affecting the final diagnostic image quality, allowing scatter correction to be applied computationally rather than mechanically.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If opaque masks are inserted in the X-ray beam to estimate scattered radiation, then scattered radiation can be measured, but additional image acquisition is required which is not feasible for single-image radiography

Engineering Contradiction:

Improvescattered radiation measurementVSAvoidimage acquisition efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent merges the scatter measurement function with the existing pre-exposure image acquisition step that is already performed for automatic exposure control and positioning. By utilizing the pre-exposure image that is routinely taken before the diagnostic image, the system obtains scatter information without requiring any additional image acquisitions, thus maintaining single-image radiography workflow.

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If anti-scatter mechanical grids are used, then scattered radiation is reduced, but image quality still degrades due to incomplete scatter prevention

Engineering Contradiction:

Improvescattered radiationVSAvoidimage quality

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent replaces the imperfect mechanical scatter prevention of anti-scatter grids with a computational scatter removal method. The system measures actual scatter in the pre-exposure image and subtracts it from the diagnostic image, achieving complete scatter removal rather than the partial prevention (15-20% transmission) provided by mechanical grids.

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 approach enhances image quality by accurately correcting for X-ray scatter without increasing the X-ray dose or needing additional image acquisitions, effectively addressing the limitations of existing methods.

Implementation Method 1

a mask comprising radio-opaque elements is in an acquisition position, the acquisition position being when the mask is in the X-ray pathway leading from the source to the object

Methodology Applied

Scientific EffectX-ray absorption by radio-opaque materials: Absorption (EM radiation)

Implementation Method 2

when X-rays pass through the object, a phenomenon of scattering is observed, resulting from interaction between the X-rays and the different constituent materials of the object

Methodology Applied

Scientific EffectX-ray scattering: Scattering

Data Source

PatentUS8867700B2Method for estimating and correcting scattering in mammography

Publication Date: 2014.10.21 GE PRECISION HEALTHCARE LLC

AI summary

A method for correcting at least one image of an object obtained with a mammography system is provided. The method comprises: acquiring a pre-exposure image of an object to determine the acquisition conditions for main images, the pre-exposure image comprising regions corresponding to the projection of radio-opaque elements, wherein a mask comprising radio-opaque elements is in an acquisition position; acquiring the main images resulting from the passing through the object of X-rays at higher doses than the dose used for acquisition of the pre-exposure image, wherein the mask comprising radio-opaque elements is in a retracted position; extracting regions from the pre-exposure image which correspond to the projection of radio-opaque elements; and determining the contribution of X-ray scatter at every point of the at least one image of the object, on the basis of the regions extracted from the pre-exposure image.