Scattered Radiation Correction Using Virtual Reference Image
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Solution Overview
Problem
Existing methods for correcting scattered radiation in three-dimensional medical images are prone to errors and require mechanical interventions or prior knowledge of the object's materials, leading to suboptimal image quality and potential removal of medically relevant structures.
Innovation Solution
A method that uses a virtual three-dimensional reference image and an adaptive scattering model to correct scattered radiation in three-dimensional medical images, without mechanical intervention, by iteratively subtracting the scattering model from the projection images and comparing the results with the reference image until a quality parameter meets an abort criterion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an anti-scatter grid is positioned in front of the detector to filter scattered radiation, then scattered radiation is reduced, but direct radiation is also filtered out requiring higher dose
Solution Approach 1:
The patent extracts and removes the scattering effect from the projection images by determining a scattering model that represents scattered radiation and subtracting it from the measured projection images. This eliminates scattered radiation without requiring physical filters that would also block direct radiation and increase dose.
Solution Approach 2:
The patent replaces the mechanical anti-scatter grid system with a computational approach. Instead of using physical hardware to filter radiation, the method uses software-based scattering model determination and subtraction to remove scattered radiation effects from the images.
2Object-affected harmful factors
If large distance is provided between object and detector to reduce scattered radiation, then scattered radiation is reduced, but magnification increases requiring large expensive detectors
Solution Approach 1:
The patent replaces the mechanical solution of increasing object-detector distance with a computational method. The scattering model subtraction technique allows scattered radiation reduction without changing the physical geometry of the imaging system, thereby maintaining appropriate magnification and detector size.
3Object-affected harmful factors
If trained function is applied to remove scattered radiation from projection images, then scattered radiation is reduced, but medically relevant structures may be removed
Solution Approach 1:
The patent performs preliminary action by determining the scattering model before subtracting it from the projection images. The scattering model is determined based on the specific object and imaging conditions, allowing tailored correction that preserves medically relevant structures while removing scattered radiation.
Solution Approach 2:
The patent replaces error-prone trained functions with a physics-based scattering model determination approach. This computational method uses the actual imaging geometry and object characteristics to model scattered radiation, providing more reliable and accurate correction compared to generic trained functions.
4Object-affected harmful factors
If Boltzmann transport equation is solved to model scattered radiation, then scattered radiation can be corrected, but the method is computationally intensive and prone to error
Solution Approach 1:
The patent changes the parameters and complexity of the scattering model to be more computationally efficient. Instead of solving the full Boltzmann transport equation, the method uses a simplified scattering model determination that is adapted to the specific imaging situation, reducing computational complexity while maintaining accuracy.
Solution Approach 2:
The patent applies partial action by using a simplified scattering model that addresses the most significant scattered radiation effects without attempting to model all possible scattering interactions. This provides sufficient correction for medical imaging purposes while avoiding excessive computational complexity.
5Object-affected harmful factors
If low-frequency function is used to model scattered radiation with iterative adaptation, then scattered radiation can be corrected, but prior knowledge of materials is required and it is computationally intensive
Solution Approach 1:
The patent changes the approach from using low-frequency functions with iterative material-based adaptation to a scattering model determination that does not require prior knowledge of object materials. The model is determined directly from the imaging geometry and measured data, simplifying the computational process.
Solution Approach 2:
The patent extracts the scattering model directly from the imaging situation without requiring extraction or input of material composition information. This eliminates the need for prior knowledge of object materials while still providing accurate scattered radiation correction.
Data Source
AI summary
A computer-implemented method for scattered radiation correction, comprises: receiving a plurality of projection images mapping an object; receiving or determining a virtual three-dimensional reference image mapping the object; determining at least one scattering model; subtracting the at least one scattering model from the projection images to determine corrected projection images; determining a corrected medical image as a function of the corrected projection images; comparing the corrected image with the virtual reference image; and checking whether an abort criteria is met. If the abort criteria is met, then the corrected medical image is provided. If the abort criteria is not met, then the at least one scattering model is adapted and the method is repeated based on the adapted scattering model.