Electron Beam Control for Faster CT Voltage Switching
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Solution Overview
Problem
Existing computed tomography scanners face challenges in reducing the time required to switch between different energy levels for spectral imaging, as current methods are inefficient in transitioning between low and high voltage modes in electron beam generators.
Innovation Solution
The method involves controlling the power drawn by the electron beam generator during transitions between low and high voltage modes, utilizing an electron beam steering module to direct the beam to an X-ray suppression surface during transitions, and modifying the focal spot size and position to minimize X-ray generation during these transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the voltage level is switched quickly between low and high modes for spectral imaging, then the imaging speed and efficiency are improved, but the transition time between voltage modes becomes excessively long
Solution Approach 1:
The electron beam is steered to the X-ray suppression surface before the voltage transition begins, and the focal spot is pre-positioned to minimize X-ray generation during the transition phase. This preliminary positioning ensures that when the voltage switches occur, the beam is already in the correct position to suppress harmful radiation while the voltage changes.
Solution Approach 2:
The system dynamically adjusts the focal spot size and position during voltage transitions. By making the focal spot variable in size and position rather than fixed, the system can optimize beam characteristics in real-time during transitions, allowing faster switching while maintaining control over X-ray generation.
2Loss of time
If the electron beam generator operates at high power during transitions to reduce transition time, then the switching speed is improved, but excessive X-rays are generated during the transition phase
Solution Approach 1:
The harmful X-ray generation function is extracted from the transition phase by steering the electron beam to a dedicated X-ray suppression surface. This separate surface is specifically designed to absorb or redirect electrons without generating harmful X-rays in the detection direction, effectively removing the harmful effect from the transition process.
Solution Approach 2:
The X-ray suppression surface acts as an intermediary between the electron beam and the detection system during transitions. This intermediate surface intercepts the electron beam and converts its energy in a controlled manner that does not produce harmful X-rays in the detection direction, mediating between the high-power beam and the need to suppress radiation.
3Manufacturing precision
If the focal spot size is reduced to improve spatial resolution during transitions, then the imaging precision is improved, but the power drawn by the electron beam generator increases
Solution Approach 1:
The system applies different focal spot characteristics to different spatial locations and time phases. During normal imaging, an optimized focal spot size is used for each mode. During transitions, the focal spot is specifically positioned and sized to match the suppression surface geometry, creating local optimization for the transition phase rather than using a single fixed focal spot configuration.
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 significantly reduces the transition time between voltage modes, ensuring minimal X-ray emission during transitions, thereby improving the efficiency and speed of spectral imaging in computed tomography scanners.
Implementation Method 1
an electron beam generator to generate an electron beam... in which a first voltage level is used to generate the electron beam
Implementation Method 2
an X-ray generation surface, which emits X-rays responsive to incident electrons (from the electron beam)
Data Source
AI summary
A mechanism for controlling an electron beam generator of an X-ray tube that switches between a low voltage mode and a high voltage mode. The proposed mechanism, during a transition between the low and high voltage modes, controls a power drawn by the electron beam generator. In particular, during a transition from a low voltage mode to a high voltage mode, the drawn power is reduced and, during a transition from a high voltage mode to a low voltage mode, the drawn power is increased.