Flying Focal Spot CT Interpolation Interlacing
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Solution Overview
Problem
Helical multislice CT systems suffer from windmill artifacts due to insufficient axial sampling, which cannot be practically increased by reducing detector size, and existing methods like flying focal spot and zero-interleaving require time-consuming rebinning and resampling.
Innovation Solution
The method involves using a flying focal point x-ray source with interpolation interlacing, specifically zero or weighted zero interlacing, to increase axial sampling density without rebinning or resampling, effectively reducing windmill artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detector size is reduced to increase axial sampling density, then axial sampling resolution is improved, but detector manufacturing complexity and cost increase
Solution Approach 1:
The detector array is divided into multiple independently controllable detector groups that can be selectively activated. Instead of using all detectors simultaneously, the system segments the detection process across multiple views, activating only subsets of detectors in each view to achieve effective higher sampling density without requiring physically smaller detectors
Solution Approach 2:
The system dynamically controls which detector groups are active in each view through the view activation module. The activation pattern changes between views, creating a time-varying detection configuration that effectively increases sampling density without static hardware changes
2Measurement precision
If rebinning and resampling is performed to increase axial sampling, then axial sampling density is improved, but processing time and computational complexity increase
Solution Approach 1:
The system performs view activation and data selection in advance during the data acquisition phase, organizing projection data by detector group and view index before reconstruction. This preliminary organization eliminates the need for time-consuming rebinning and resampling operations during the reconstruction phase
Solution Approach 2:
The invention extracts and separates the sampling density enhancement function from the reconstruction process. By using view activation to select specific detector groups for specific views, the effective sampling density is increased without requiring extraction and reorganization of data through rebinning operations
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 axial sampling density without the need for physical detector size reduction or time-consuming rebinning, effectively reducing windmill artifacts while maintaining signal-to-noise ratio and improving image resolution.
Implementation Method 1
REB represents the position of the electron beam on the anode in the radial direction, which, due to the angled shape of the anode, has a corresponding focal spot position zfs in the axial direction. Deflection of the electron beam position REB to ±ΔSOD results in two focal spots at zfs=±δ in the axial direction
Implementation Method 2
an x-ray detector disposed to receive x-rays from the x-ray source
Data Source
AI summary
A method of computed-tomography and a computed-tomography apparatus where a flying focal spot x-ray interpolation interlacing is used. Weighted or non-weighted interlacing of zero values is performed, or interpolation interlacing is performed. The interpolation interlacing may be implemented as part of backprojection and or may be a separate process prior to backprojection. In both cases interlacing is performed on post-logged convolved data. The interpolation interlacing may also be incorporated into different parts of the processing chain, such as before convolution.