Tomosynthesis AEC Calibration for Wide-Angle Exposure Accuracy
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Solution Overview
Problem
Wide-angle tomosynthesis systems face challenges in accurately calculating automatic exposure control (AEC) dosage due to variations in x-ray path length and detector count shifts caused by large projection angles, which affect image quality and radiation exposure.
Innovation Solution
The system generates reference detector count maps at various projection angles and uses curve fitting to estimate detector count values, adjusting for heel and angle effects, to calculate the AEC x-ray dosage needed for wide-angle tomosynthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wide-angle tomosynthesis is performed with large projection angles, then image coverage and diagnostic capability are improved, but calculation accuracy of AEC dosage deteriorates due to x-ray path length variations and detector count shifts
Solution Approach 1:
The system performs preliminary calibration by acquiring reference images at multiple known projection angles with a known reference mAs value. These reference images are used to pre-calculate calibration factors that account for path length variations and detector count shifts. During actual tomosynthesis, these pre-calibrated factors are applied to accurately determine the mAs at each projection angle without real-time complex calculations.
Solution Approach 2:
The patent replaces complex real-time mechanical measurement and calculation systems with a computational approach. Instead of using complex hardware to measure and compensate for path length variations, the system uses software-based calibration factors derived from reference images to substitute for direct measurement, simplifying the system while maintaining accuracy.
2Device complexity
If conventional AEC methods are used in wide-angle tomosynthesis, then system complexity is reduced, but image quality and radiation exposure control deteriorate
Solution Approach 1:
The patent introduces calibration factors as an intermediary element between the reference images and the actual tomosynthesis images. These calibration factors serve as a mediator that translates the known reference mAs values to the actual mAs values at each projection angle, enabling accurate radiation dose control without requiring complex real-time measurement systems.
Solution Approach 2:
The system performs preliminary calibration by acquiring reference images at multiple known projection angles with a known reference mAs value. These reference images are used to pre-calculate calibration factors that account for path length variations and detector count shifts. During actual tomosynthesis, these pre-calibrated factors are applied to accurately determine the mAs at each projection angle without real-time complex calculations.
3Device complexity
If conventional AEC methods are used in wide-angle tomosynthesis, then device complexity is reduced, but radiation exposure control deteriorates
Solution Approach 1:
The patent replaces complex real-time mechanical measurement and calculation systems with a computational approach. Instead of using complex hardware to measure and compensate for path length variations, the system uses software-based calibration factors derived from reference images to substitute for direct measurement, simplifying the system while maintaining accuracy.
Solution Approach 2:
The patent introduces calibration factors as an intermediary element between the reference images and the actual tomosynthesis images. These calibration factors serve as a mediator that translates the known reference mAs values to the actual mAs values at each projection angle, enabling accurate radiation dose control without requiring complex real-time measurement systems.
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 method ensures accurate calculation of AEC dosage, minimizing radiation exposure while maintaining clear image quality for detecting breast abnormalities, even at large projection angles.
Implementation Method 1
x-ray source moves relative to the breast. The x-ray images are then processed into a stack of 2D images
Data Source
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Figure 2
AI summary
The present application discloses a system and method to calculate the automatic exposure control (AEC) calibrated dosage for tomosynthesis sweeps. For example, reference images may be acquired, and corresponding reference detector count maps may be generated and stored for a plurality of projection angles using the tomosynthesis imaging system. The tomosynthesis imaging system may then acquire a scout image using a scout dosage, identify the densest region within the scout image, and calculated the average detector count values associated with the densest region. The AEC calibrated dosage can be calculated based on a ratio of the average reference detector count values, corresponding to the detector count values of pixels with a corresponding densest region of the reference image, and the calculated average detector count values.