Flattened-Breast X-Ray Tomosynthesis for Thickness Resolution
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Solution Overview
Problem
Existing x-ray imaging modalities for breast cancer detection, such as mammography and whole-body CT, face challenges in achieving high spatial resolution in the thickness direction of a flattened breast while minimizing radiation dose and patient discomfort.
Innovation Solution
A multi-mode x-ray breast imaging system that includes enhanced tomosynthesis (ET) and breast-only CT modes, utilizing supplemental projection images from varied source trajectories and adjustable x-ray parameters to enhance spatial resolution and reduce radiation dose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional mammography uses a single projection image, then the imaging process is simple and fast, but spatial resolution in the thickness direction is insufficient
Solution Approach 1:
The patent segments the imaging process into multiple projection images taken at different source positions around the breast. Instead of a single projection, the system acquires multiple images (e.g., 15-30 projections) at angular intervals, then reconstructs them into 3D voxel data. This segmentation enables thickness-direction resolution while maintaining computational manageability through structured acquisition protocols.
Solution Approach 2:
The patent transitions from 2D projection imaging to 3D tomographic imaging by adding the angular dimension. The source moves around the breast through a trajectory (e.g., ±15° to ±30° arc), and the system reconstructs images across three dimensions (x, y, and thickness/z directions). This dimensional expansion provides spatial resolution in the thickness direction without requiring additional physical compression.
Solution Approach 3:
The patent employs dynamic source positioning where the x-ray source moves along a defined trajectory around the breast during the imaging sequence. The source position is dynamically adjusted across multiple angles, and the system reconstructs images based on these dynamic positions. This dynamic approach enables 3D reconstruction and improves spatial resolution while keeping the overall imaging time manageable.
2Measurement precision
If enhanced tomosynthesis uses multiple projection images from varied trajectories, then spatial resolution is improved, but radiation dose increases
Solution Approach 1:
The patent optimizes imaging parameters including the angular trajectory range (e.g., ±15° to ±30°), number of projections, kVp (e.g., 28-32 kVp for breast imaging), and mAs settings. By carefully selecting these parameters, the system achieves adequate spatial resolution while controlling the total radiation dose. The trajectory parameters are adjusted to minimize the number of required projections while maintaining image quality.
Solution Approach 2:
The patent uses a partial trajectory approach where the source moves through a limited angular range (e.g., ±15° to ±30°) rather than a full 360° rotation. This partial action reduces the total number of projections needed and consequently lowers the radiation dose while still providing sufficient 3D information for diagnostic purposes. The system avoids excessive imaging actions that would unnecessarily increase dose.
3Measurement precision
If the breast is compressed more strongly, then image quality improves, but patient comfort decreases and compression force increases
Solution Approach 1:
The patent replaces strong mechanical compression with a tomosynthesis imaging approach that uses multiple low-dose projections from different angles. Instead of relying on high compression forces to improve image quality, the system uses computational reconstruction from multiple angled views. This substitution maintains image quality while dramatically reducing the compression force required during the imaging process.
Solution Approach 2:
The patent employs dynamic image reconstruction that processes multiple projections captured during a moving source trajectory. The dynamic acquisition and reconstruction process allows for adequate image quality without requiring static, strong compression. The system captures images at multiple angles while the breast remains in a lighter compression state, and the 3D reconstruction compensates for the reduced compression through algorithmic processing.
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
Improves spatial resolution in the thickness direction of a flattened breast without increasing radiation dose, while maintaining patient comfort and reducing the need for excessive compression force.
Implementation Method 1
a first x-ray source and a first imaging x-ray receptor configured to image the breast in an enhanced tomosynthesis mode ET
Data Source
AI summary
Systems and methods for breast x-ray tomosynthesis that enhance spatial resolution in the direction in which the breast is flattened for examination. In addition to x-ray data acquisition of 2D projection tomosynthesis images ETp1 over a shorter source trajectory similar to known breast tomosynthesis, supplemental 2D images ETp2 are taken over a longer source trajectory and the two sets of projection images are processed into breast slice images ETr that exhibit enhanced spatial resolution, including in the thickness direction of the breast. Additional features include breast CT of an upright patient's flattened breast, multi-mode tomosynthesis, and shielding the patient from moving equipment.