X-ray Tomosynthesis Reconstruction Coordinate Alignment
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Solution Overview
Problem
In combined X-ray imaging systems, the reconstruction of slice images from tomosynthesis recordings using either Cartesian or perspective coordinate systems prevents direct alignment with radiography recordings, leading to navigation challenges due to mismatched voxel positions.
Innovation Solution
A method for generating combined X-ray image data by using a shared X-ray beam source and detector to record radiographic and tomosynthesis data sets from different positions, with the tomosynthesis data set reconstructed in a perspective coordinate system adapted to the radiography system's geometry, ensuring voxel positions match pixel positions, allowing for consistent image data reconstruction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If tomosynthesis recordings are reconstructed using Cartesian or perspective coordinate systems, then the reconstruction can be performed with standard algorithms, but the voxel positions do not align with radiography recording pixel positions, preventing direct navigation
Solution Approach 1:
The patent changes the coordinate system parameters from standard Cartesian or perspective systems to a modified perspective coordinate system specifically adapted to match the radiography system's geometric parameters (focal spot position, detector position, magnification factor). This parameter adaptation ensures that voxels in the tomosynthesis reconstruction align precisely with pixels in the radiography recording, enabling direct navigation while maintaining standard reconstruction algorithms
Solution Approach 2:
The patent introduces an intermediary coordinate transformation layer that maps between the tomosynthesis projection data and the radiography coordinate system. This intermediary transformation uses the geometric relationship between the two systems (shared focal spot and detector positions) to ensure that the reconstructed voxels correspond to the correct pixel positions in the radiography image, solving the alignment problem without requiring changes to the fundamental reconstruction process
2Adaptability or versatility
If a combined X-ray system uses different distances between X-ray beam source and detector for radiography and tomosynthesis, then both modalities can be implemented, but the reconstructed slices no longer match the radiography image
Solution Approach 1:
The patent adjusts the reconstruction parameters of the tomosynthesis data to match the radiography system's geometric parameters. Even though the physical distances differ between radiography and tomosynthesis acquisitions, the reconstruction uses the radiography system's focal spot-to-detector distance and magnification factor as reference parameters. This ensures that the reconstructed slices maintain consistent geometric relationships with the radiography image, enabling accurate navigation and measurement across both modalities
3Loss of information
If tomosynthesis is recorded from multiple positions, then three-dimensional information is obtained, but the angular range limitations cause out-of-plane artifacts that do not remain stationary in the image
Solution Approach 1:
The patent modifies the coordinate system parameters to account for the limited angular range of the tomosynthesis acquisition. By using a perspective coordinate system adapted to the specific geometry and angular coverage, the reconstruction properly localizes out-of-plane artifacts to their correct spatial positions. This prevents artifacts from appearing to move or drift in the image, as their positions are accurately determined by the geometric parameters of the acquisition 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
Enables direct navigation and alignment of image regions between radiography and tomosynthesis recordings, improving diagnostic efficiency by maintaining consistent coordinate systems and reducing artifacts.
Implementation Method 1
a radiographic X-ray projection data set, which was recorded from an examination object from a first position by a radiography X-ray system
Data Source
AI summary
A method for generating combined X-ray image data of an examination object comprises: receiving a radiographic X-ray projection data set, which was recorded from an examination object from a first position by a radiography X-ray system; receiving a tomosynthesis X-ray projection data set, which was recorded from the examination object from a second position, which differs from the first position, by way of a tomosynthesis imaging system; generating a 2D image data set in a perspective coordinate system adapted to the geometry of the radiography X-ray system based on the radiographic X-ray projection data set; and generating a three-dimensional tomosynthesis image data set in the perspective coordinate system adapted to the geometry of the radiography X-ray system based on the tomosynthesis X-ray projection data set.