Iterative Volume Image Reconstruction Using Synthetic Projections
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current diagnostic imaging techniques, such as cone-beam computed tomography (CBCT), face challenges in reducing patient exposure to X-ray radiation and minimizing image artifacts like view aliasing, which affect the quality and accuracy of 3D volume reconstruction.
Innovation Solution
A method that involves obtaining a set of acquired projection images, generating synthetic projection images, and combining them with the acquired images for iterative reconstruction, allowing for reduced patient exposure and improved image quality by selectively using synthetic images in the reconstruction process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the number of X-ray exposures is reduced to limit patient radiation exposure, then patient safety is improved, but image quality deteriorates and view aliasing artifacts increase
Solution Approach 1:
The patent creates synthetic projection images that are copies or simulations of what additional real projections would look like. These synthetic images are generated by forward-projecting the initial 3D volume reconstruction to create virtual views at angles where no actual measurements were taken, effectively copying the information that would have been obtained from additional X-ray exposures without actually exposing the patient to more radiation.
Solution Approach 2:
The patent performs preliminary reconstruction using the limited acquired projections to create an initial volume estimate before generating the synthetic projections. This preliminary action allows the system to create synthetic views based on an initial reconstruction, which are then used to refine the final image quality without requiring additional patient exposure.
2Manufacturing precision
If more projection images are acquired to improve reconstruction accuracy, then image quality is improved, but patient radiation exposure increases
Solution Approach 1:
Instead of acquiring additional real projection images that would require more patient exposure, the patent generates synthetic copies of these projections by forward-projecting the initial volume reconstruction. This allows the reconstruction algorithm to work with a complete set of angular views without actually taking additional measurements from the patient.
Solution Approach 2:
The patent introduces synthetic projection images as an intermediary between the limited acquired projections and the final reconstruction. These synthetic images act as a bridge, providing the missing angular information needed for accurate reconstruction without requiring additional direct measurements from the patient.
3Manufacturing precision
If iterative reconstruction with synthetic projections is performed for multiple iterations, then image quality and artifact reduction are improved, but processing time increases
Solution Approach 1:
The patent performs preliminary generation of synthetic projections using the initial reconstruction before entering the iterative refinement process. This preliminary action prepares the data structures and synthetic views in advance, so that during iterative refinement, the system only needs to perform updates rather than generating synthetic projections from scratch each iteration, reducing overall processing time.
4Object-generated harmful factors
If synthetic projection images are generated and combined with acquired images, then view aliasing artifacts are reduced, but computational complexity increases
Solution Approach 1:
The patent generates synthetic projections by forward-projecting the initial volume reconstruction, creating copies of what the projections would look like at unmeasured angles. This copying approach provides the complete angular sampling needed to eliminate view aliasing artifacts without requiring complex alternative reconstruction algorithms.
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 reduces the number of required X-ray exposures, minimizes view aliasing artifacts, and enhances image quality, particularly in regions of fine detail, while maintaining artifact-free reconstruction.
Implementation Method 1
The X-ray source directing, from various points along its orbit around the subject, a divergent cone beam of X-rays toward the subject
Data Source
AI summary
A method for imaging a subject obtains a first set of acquired projection images of a subject volume, wherein each projection image in the first set has a corresponding acquisition angle and forms an initial reconstructed volume image. A second set of synthetic projection images is generated according to processing of the acquired projection images and combined with the first set to form a combined set of projection images. The method augments the initial reconstructed image to form an improved reconstructed image by at least a first iteration of an iterative reconstruction process using the initial reconstructed image with the combined set of acquired and synthetic projection images and at least a subsequent iteration of the iterative reconstruction process using the first set of acquired projection images and fewer than, or none of, the second set of synthetic projection images. The improved reconstruction image is rendered on a display.