CT X-Ray Tube Cathode Layout for Stable Moving Focal Spots
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Solution Overview
Problem
Existing X-ray CT apparatuses experience focal blur and image degradation due to variations in the size of the X-ray focal spot caused by changes in the electron beam's trajectory, which is not effectively addressed by existing methods that move the focal spot to prevent overheating.
Innovation Solution
An X-ray CT apparatus with a cathode having multiple electron sources arranged in a plane facing the anode, allowing selective control of the electron beam emission position based on the target position of the X-ray focal spot, thereby maintaining a consistent focal spot size without altering the electron beam's trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the X-ray focal spot is moved to prevent overheating of the anode, then the heat dissipation is improved, but the focal spot size varies causing focal blur and image quality degradation
Solution Approach 1:
The cathode is divided into multiple electron sources (first electron source and second electron source) arranged in a plane facing the anode. Each electron source can be independently controlled to emit electron beams toward different target positions on the anode, allowing the focal spot to be moved between multiple discrete positions without varying its size, thus preventing overheating while maintaining consistent focal spot dimensions.
Solution Approach 2:
The system dynamically switches between multiple electron sources based on the required target position on the anode. By selectively activating appropriate electron sources, the focal spot position is changed while maintaining constant focal spot size, enabling continuous operation without overheating while preserving image quality.
2Temperature
If the electron beam trajectory is changed to move the focal spot, then the heat distribution is improved, but the focal spot size varies causing focal blur
Solution Approach 1:
Instead of continuously changing the electron beam trajectory, the cathode is segmented into multiple discrete electron sources positioned at specific locations. Switching between these segmented sources changes the focal spot position on the anode while maintaining consistent focal spot size, improving heat distribution without causing focal blur.
Solution Approach 2:
Each electron source is designed to emit electron beams with identical characteristics (same focal spot size) but directed toward different local positions on the anode. This local quality consistency ensures that while the focal spot position changes for heat distribution, the focal spot size remains constant, preventing focal blur.
3Manufacturing precision
If multiple electron sources are used to move the focal spot without changing trajectory, then the focal spot size consistency is improved, but the device complexity increases
Solution Approach 1:
The cathode is segmented into multiple electron sources that can be independently controlled. This segmentation allows the focal spot position to be changed by switching between sources rather than moving a single source, maintaining focal spot size consistency while the increased number of sources adds some structural complexity.
Solution Approach 2:
Multiple electron sources share the same structural design and emission characteristics, making them functionally equivalent but spatially distinct. This universality allows the system to achieve focal spot positioning through source selection rather than trajectory adjustment, where the complexity is offset by the repeated use of a standardized electron source module.
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 reduces focal blur and maintains image quality by ensuring a constant focal spot size during movement, enhancing the resolution and clarity of tomographic images.
Implementation Method 1
a cathode that generates an electron beam and an anode that collides with the electron beam to radiate an X-ray
Implementation Method 2
causes an electron beam emitted from the cathode to collide with the anode to radiate an X-ray from an X-ray focal spot that is a point of collision of the electron beam
Data Source
AI summary
Provided are an X-ray CT apparatus and a control method of the same capable of reducing focal blur even in a case where an X-ray focal spot is moved.There is provided an X-ray CT apparatus including: an X-ray tube including a cathode that generates an electron beam and an anode that collides with the electron beam to radiate an X-ray; an X-ray detector configured to detect the X-ray; a rotating plate configured to rotate the X-ray tube and the X-ray detector around a subject; and an image processing unit configured to generate a tomographic image of the subject based on projection data acquired by the X-ray detector during rotation of the rotating plate, in which the cathode, which has a plurality of electron sources that are arranged within a plane facing the anode and emit the electron beam, is configured such that a position of an electron source, from which an electron beam is to be emitted, is selectively controlled based on a target position of an X-ray focal spot in the anode.