Tomosynthesis Reconstruction with Exponential Convolution Kernel

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Solution Overview

Problem

Conventional mammography methods produce 2D x-ray images that overlay tissue layers, making it difficult to detect tumors, while tomosynthesis provides limited 3D image quality due to incomplete scanning, resulting in reduced depth resolution and inability to quantify attenuation coefficients.

Innovation Solution

A tomosynthesis image reconstruction method using a discrete convolution kernel based on an exponential function for filtered back projection, which enhances image quality by emphasizing edge visualization and allowing diagnostic evaluation with minimal processing effort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional 2D x-ray mammography is used, then the imaging process is simple and fast, but tissue layers are overlaid making tumor detection difficult

Engineering Contradiction:
Improveimaging speedVSAvoidtumor detectability
Core Design Contradiction:
ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent transitions from 2D planar imaging to 3D volumetric imaging by introducing a tomographic dimension. Multiple projection images acquired at different angles are reconstructed into a 3D volume, allowing visualization of breast tissue in depth without overlay artifacts, thereby improving tumor detectability while maintaining imaging efficiency

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of time

If tomosynthesis with restricted angular range is used, then processing time is reduced, but depth resolution deteriorates

Engineering Contradiction:
Improveprocessing timeVSAvoiddepth resolution
Core Design Contradiction:
Loss of timeVSMeasurement precision

Solution Approach 1:

The patent employs iterative reconstruction algorithms that optimize reconstruction parameters including angular sampling density, iteration count, and regularization strength. By adjusting these parameters, the system achieves acceptable depth resolution with fewer projection angles, thereby reducing processing time while maintaining diagnostic quality

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses partial scanning with a restricted angular range (e.g., 15-30 degrees) rather than complete 360-degree scanning. This partial action approach provides sufficient depth resolution for diagnostic purposes while dramatically reducing acquisition and processing time compared to full tomographic scanning

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If complete tomographic scanning is used, then depth resolution is improved, but processing effort and time increase significantly

Engineering Contradiction:
Improvedepth resolutionVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements partial scanning with a limited angular range that provides sufficient depth resolution for clinical diagnosis without requiring complete tomographic coverage. This reduces the number of projection images needed, thereby decreasing processing complexity and computational burden while maintaining adequate depth resolution

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent divides the breast volume into multiple thin slices or layers during reconstruction, processing each slice independently or with localized interpolation. This segmentation approach reduces the overall computational complexity by breaking down the large-scale 3D reconstruction problem into smaller, more manageable 2D reconstruction problems

Inventive Principle:
Principle #1Segmentation

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

The method effectively generates high-quality 3D x-ray images that improve tumor detection and visualization of microcalcifications and tumors, even with incomplete scanning data, by controlling contrast and noise behavior through the parameter 'a', and reduces image errors from truncated projections.

Implementation Method 1

a digital x-ray detector which records detector signals produced by an x-ray tube

Methodology Applied
Scientific EffectX-Ray: X-Ray

Data Source

PatentUS7558366B2Tomosynthetic image reconstruction method, and diagnostic device operating according to the method
Publication Date: 2009.07.07 SIEMENS HEALTHINEERS AG
  • US7558366B2 patent drawing
  • US7558366B2 patent drawing
  • US7558366B2 patent drawing

AI summary

In a tomosynthetic image reconstruction method and diagnostic device operating with such a method, a tomosynthetic 3D x-ray image is reconstructed by a discrete filtered back projection from a number of individual digital projection data recorded from different project angles within a restricted angular range, in which at least one filtering is performed with a convolution kernel that, in the local area outside of its central value, corresponds to an exponential function.