Tomosynthesis Reconstruction via Direct Back Projection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Tomosynthesis reconstruction using filtered back projection from CT algorithms results in low spatial resolution due to geometric transformation and interpolation, increasing processing time and memory requirements.
Innovation Solution
Direct back projection of tomosynthesis images without geometric transformation into a virtual CT detector arrangement, using a tomogram diagnostic apparatus with an image processing unit that performs coefficient calculation, convolution integral, and back projection to generate high-resolution tomograms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If geometric transformation and interpolation are performed to transform tomosynthesis images into virtual CT detector arrangement, then reconstruction can be performed using standard CT algorithms, but spatial resolution decreases due to interpolation loss
Solution Approach 1:
Instead of transforming tomosynthesis images into virtual CT detector arrangement, the patent inverts the approach by directly applying back projection to the original tomosynthesis detector pixel arrangement. This eliminates the need for geometric transformation and interpolation, preserving spatial resolution while achieving reconstruction.
Solution Approach 2:
The patent extracts and removes the unnecessary geometric transformation and interpolation steps from the reconstruction process. By directly applying back projection to the original detector data without transformation, it eliminates the source of resolution loss while maintaining reconstruction capability.
2Adaptability or versatility
If geometric transformation and interpolation operations are performed, then virtual CT detector data can be obtained, but processing time increases
Solution Approach 1:
The patent removes the time-consuming geometric transformation and interpolation operations from the reconstruction pipeline. By directly applying back projection to the original tomosynthesis data, it eliminates unnecessary processing steps while preserving essential reconstruction functionality.
Solution Approach 2:
The patent skips the intermediate step of geometric transformation and directly proceeds from raw tomosynthesis detector data to tomogram reconstruction via back projection. This shortcut eliminates processing delays while achieving the same reconstruction goal more efficiently.
3Adaptability or versatility
If geometric transformation is performed to match virtual CT detector arrangement, then standard reconstruction algorithms can be used, but memory space requirements increase
Solution Approach 1:
The patent extracts and eliminates the need for storing transformed virtual detector data by directly processing the original tomosynthesis detector images. This removes the additional memory burden associated with holding transformed image data while maintaining reconstruction capability.
4Ease of operation
If interpolation is performed during geometric transformation, then pixel values can be obtained for transformed coordinates, but high-frequency information is lost
Solution Approach 1:
Instead of transforming coordinates and interpolating pixel values, the patent inverts the approach by performing back projection directly on the original detector pixel coordinates. This eliminates interpolation entirely, preserving all high-frequency information in the original data.
Solution Approach 2:
The patent removes the interpolation step from the processing chain by eliminating geometric transformation. By directly applying back projection to original detector data, it extracts only the essential reconstruction operation without information-lossy intermediate steps.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An image processing apparatus which processes an image obtained by tomosynthesis shooting by using a radiation source and a two-dimensional detector. The image processing apparatus includes obtaining means for obtaining a plurality of projection data output from the two-dimensional detector upon tomosynthesis shooting; and reconstruction means for performing analytical reconstruction processing of a tomogram of a subject from the plurality of projection data obtained by tomosynthesis shooting without transforming the projection data into virtual projection data on a virtual CT detection plane virtually set to be perpendicular to a radiation center direction of the radiation source.