Tomosynthesis Image Acquisition with Non-Uniform X-Ray Dose Distribution
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Solution Overview
Problem
Mammography machines produce 2D images that often lead to falsely positive or negative interpretations due to superimposed structures, and existing 3D tomosynthesis technologies struggle with sufficient spatial resolution for detecting microcalcifications, resulting in reduced visibility and increased data management complexity.
Innovation Solution
A novel method for obtaining tomosynthesis images using a non-uniform X-ray dose distribution strategy and digital filtering to enhance depth-of-focus and signal-to-noise ratio, allowing for improved detection of radiology signs by optimizing the acquisition geometries and dose distribution based on the size and class of signs to be detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a series of images are acquired at different positions along a path for 3D tomosynthesis reconstruction, then the depth resolution and ability to separate superimposed structures is improved, but the quantity of information to be managed increases significantly and access to clinical information takes much more time
Solution Approach 1:
The patent applies local quality by distributing the X-ray dose non-uniformly across different angular positions, with higher dose concentrated at the central angle (0 degrees) and lower dose at peripheral angles. This creates locally optimized image quality at different positions in the angular series, where the central projection receives sufficient dose for high-quality reconstruction while peripheral projections receive reduced dose, thereby managing the overall data quantity and complexity.
Solution Approach 2:
The patent changes the dose parameter across different angular positions in the acquisition series. By varying the dose as a function of angle (with formula I(α) = I0 * exp(-α²/(2σ²))), the system optimizes the balance between obtaining sufficient projection data for 3D reconstruction and limiting the total data management burden, thereby resolving the contradiction between depth resolution and data complexity.
2Area of stationary object
If the X-ray tube is positioned at borderline orientations far from the middle orientation, then the coverage of the breast volume is improved, but the spatial resolution and signal-to-noise ratio deteriorate due to lower assigned dose
Solution Approach 1:
The patent applies local quality by assigning different dose levels to different angular positions. Central angles (near 0 degrees) receive high dose for optimal spatial resolution and signal-to-noise ratio, while borderline angles receive lower dose. This local differentiation allows the system to achieve adequate volume coverage through multiple angles while maintaining high resolution where it matters most for clinical detection.
Solution Approach 2:
The patent uses partial action by not applying uniform high dose to all angular positions. Instead, it concentrates the majority of the dose (more than 5/9th) on the middle orientation and adjacent angles, accepting that borderline orientations will have lower resolution. This partial approach optimizes the trade-off between coverage and resolution, avoiding the excessive dose that would be required if all angles were treated equally.
3Ease of operation
If a uniform dose distribution is applied across all orientations, then the simplicity of the acquisition protocol is maintained, but the selectivity of radiology sign detection is reduced due to insufficient depth-of-focus optimization
Solution Approach 1:
The patent changes the dose parameter as a function of orientation angle, transitioning from a uniform distribution to a non-uniform distribution centered at 0 degrees. This parameter change optimizes the depth-of-focus for different angular projections, improving detection selectivity for radiology signs at various depths in the breast volume while maintaining a relatively simple automated acquisition protocol.
Solution Approach 2:
The patent implements feedback by using the known geometry of the breast and the reconstruction algorithm requirements to determine the optimal dose distribution across angles. The system automatically adjusts the dose at each angular position based on pre-calculated optimization criteria, eliminating the need for manual protocol adjustment while achieving superior detection selectivity compared to uniform dosing.
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 enhances the selectivity and efficiency of radiology sign detection, reducing the time to review clinical data and improving image quality by ensuring optimal propagation of the signal-to-noise ratio and appropriate depth-of-focus for various radiology signs, particularly microcalcifications.
Implementation Method 1
a body is subjected, during an exposure, to an X-ray irradiation by means of an X-ray tube
Implementation Method 2
a first projection image corresponding to this first orientation is recorded
Data Source
AI summary
In a method for the obtaining a tomosynthesis image for a more selective detection of radiology signs, a dose distribution strategy is proposed. The strategy is defined as a function of a substantially uniform depth-of-focus for a variety of sizes and classes of radiology signs. This strategy is coupled with a digital filtering aimed at ensuring optimum propagation of the signal-to-noise ratio beyond the frequency spectrum. This digital filtering is done by means of a class of adaptive filters required to control the propagation of the noise during the reconstruction. The filter to be applied to each projection of the X-ray tube (4) depends on the dose assigned to this projection.