Large-Area X-Ray Imaging Using Tomosynthetic Forward Projections
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Solution Overview
Problem
Existing x-ray imaging systems, such as mobile or stationary C-arms, are limited to capturing a small area due to detector size, leading to artifacts and distortions when combining multiple images, especially in interventions requiring large-area imaging like spinal column representation or contrast agent tracking, and cannot handle scene changes effectively.
Innovation Solution
A method involving recording x-ray images using different geometries, reconstructing a tomosynthetic volume, and generating synthetic forward projections to create an artifact- and distortion-free large-area x-ray image, which can be displayed on a touch or GUI-capable device, using software updates or computer programs to enhance existing systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple x-ray images are simply combined using image registration, then the coverage area is extended, but artifacts and distortions arise due to cone beam geometry and different view angles
Solution Approach 1:
The patent transitions from 2D image stitching to 3D tomosynthesis by reconstructing a volumetric representation of the imaged object. Multiple x-ray images taken at different angles are processed to create a 3D volume, which is then sliced into 2D sections. This dimensional transformation resolves the congruency problem by providing a consistent 3D reference frame that accounts for different view angles and eliminates artifacts from simple 2D concatenation.
2Device complexity
If planar detectors are used with x-ray point sources, then the imaging system is simple, but objects further from the central detector point become increasingly distorted
Solution Approach 1:
The patent creates a virtual copy of the imaging process through synthetic forward projections. The reconstructed 3D volume allows generation of synthetic x-ray images from any desired viewpoint and geometry. This virtual copying enables distortion-free imaging by selecting optimal projection geometries and compensating for detector limitations through computational methods rather than hardware changes.
3Loss of information
If contrast agents are injected during imaging, then diagnostic information is enhanced, but image registration fails due to scene changes and spreading of the contrast agent
Solution Approach 1:
By reconstructing a 3D tomosynthetic volume, the system creates a temporal and spatial reference framework that captures the evolving contrast agent distribution. The 3D volume allows tracking of contrast agent movement through time and space, maintaining registration reliability even as the scene changes. Multiple time points can be reconstructed and compared in three dimensions, preserving diagnostic information about contrast flow while maintaining geometric consistency.
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 the generation of a seamless, large-area x-ray image with reduced artifacts and distortions, allowing for precise medical procedures by aligning the preview image with the current device orientation and handling scene changes, such as contrast agent injection.
Implementation Method 1
an x-ray device which generates x-rays in a fan beam geometry
Data Source
AI summary
Method for providing a large-area x-ray image of an object mounted by means of an object platform and providing additional synthetic x-ray projections, comprising Recording of a plurality of x-ray projections by means of an x-ray device, wherein the plurality of x-ray projections are recorded during a linear movement of the object platform and/or the x-ray device; preparation of at least one tomographic volume from the plurality of x-ray projections; preparation of at least one first synthetic forward projection from the at least one tomographic volume, wherein the at least one synthetic forward projection yields a large-area x-ray image; representation of the large-area x-ray image on a suitable display device; selection and/or marking of an area of interest within the large-area x-ray image; preparation of at least one second synthetic forward projection comprising the area of interest; representation of the at least one second synthetic forward projection on a suitable display device; characterised in that the at least one second synthetic forward projection is prepared in a projection geometry that corresponds to the current orientation of the x-ray device in space.