CT X-Ray Focal Spot Control for Higher-Resolution Scans
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing CT systems face issues with focal spot sizing, leading to lower spatial resolution in views scanned at lower currents and artifacts in reconstructed images due to fixed focal spot size during continuous X-ray exposure, which is not adjusted based on varying current levels.
Innovation Solution
A CT system with an X-ray tube and controller that dynamically adjusts focal spot size during a scan based on current levels, selecting larger or smaller focal spots for different current ranges to enhance overall spatial resolution and reduce artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the smallest available focal spot is selected to support the maximum instantaneous tube power, then the spatial resolution is high for views at the highest prescribed current, but the spatial resolution becomes lower for views at lower prescribed currents
Solution Approach 1:
The patent applies dynamics by enabling the focal spot size to change dynamically during a continuous X-ray exposure based on the prescribed current level. The system transitions from a static focal spot size selection to a dynamic adjustment mechanism where the focal spot size is modulated in real-time according to the current being applied, allowing optimal spatial resolution for each current level without interrupting the exposure
Solution Approach 2:
The patent implements parameter changes by modifying the focal spot size parameter as a function of the prescribed current. The system changes the physical parameter of focal spot dimensions to match the operational requirements at different current levels, thereby optimizing image quality across the entire current range used during the scan
2Power
If a fixed focal spot size is used throughout the exposure, then the tube power requirements are met, but artifacts appear in reconstructed images due to mismatch between focal spot size and current level
Solution Approach 1:
The patent changes the focal spot size parameter dynamically during the exposure based on the prescribed current level. By adjusting this parameter in real-time, the system maintains appropriate focal spot dimensions for each current level, preventing the formation of reconstruction artifacts while continuing to meet tube power requirements
Solution Approach 2:
The system employs feedback by continuously monitoring the prescribed current level and using this information to adjust the focal spot size accordingly. This closed-loop control ensures that the focal spot size always matches the operational requirements, eliminating the conditions that lead to image artifacts
3Power
If the focal spot size is selected for the highest prescribed current, then the tube power requirements are satisfied, but the overall spatial resolution decreases because the focal spot is too large for lower current views
Solution Approach 1:
The patent implements parameter changes by dynamically adjusting the focal spot size to match the prescribed current level during the exposure. This allows the system to use smaller focal spots for lower current views (improving spatial resolution) while still being capable of delivering the required tube power when higher currents are applied
Solution Approach 2:
The system transitions from a static focal spot size selection to a dynamic adjustment mechanism. The focal spot size is modulated in real-time during the continuous exposure based on the prescribed current, optimizing spatial resolution for each view without compromising the tube's power delivery capability
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 increases the quality of reconstructed images by adjusting focal spot size according to current levels, providing higher spatial resolution without artifacts, even in mA modulated scans.
Implementation Method 1
a focal spot of the electron beam on the target, where the focal spot is created by focusing the electron beam using focusing electrodes and/or magnets
Implementation Method 2
A fan-shaped or cone-shaped beam of X-rays produced by electrons colliding with the target
Data Source
Figure 1~2
Figure 3A~3B
Figure 4
AI summary
Methods and systems are provided for increasing a quality of computed tomography (CT) images. In one embodiment, a CT system (100) comprises an X-ray tube (300) and an X-ray controller (210) including one or more processors having executable instructions stored in a non-transitory memory of the CT system (100) that, when executed, cause the one or more processors to, during a first view of a CT scan of an object, focus an electron beam (312) at a first focal spot (332) on a target (304) of the X-ray tube, the first focal spot (332) of a first size; during a second view of the CT scan, focus the electron beam (312) at a second focal spot (332) on the target (304), the second focal spot (332) of a second size different from the first size; and reconstruct an image of the object from projection data including the first view and the second view.