X-ray CT Collimator Plate Groove Alignment for Flatness
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Solution Overview
Problem
Conventional X-ray CT apparatus collimators face challenges in maintaining the flatness and warpage of collimator plates, especially with wider detection ranges, leading to misalignment and artifacts in images due to instability in the mount surface and shifts in the X-ray focal point.
Innovation Solution
The proposed solution involves a detector-side collimator with an integral structure where collimator plates are supported by grooves in upper and lower supports and an abutment plate, ensuring the continuity of the X-ray focal point and maintaining flatness by forming grooves at the same pitch to align collimator plates properly, reducing the need for alignment between modules and minimizing maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the detection range in the slice direction is widened to about 200 mm or more, then the detection capability is improved, but the flatness and warpage of collimator plates cannot be maintained due to insufficient rigidity
Solution Approach 1:
The collimator is divided into multiple modules, each covering about 20 channels of the detector. Each module contains multiple collimator plates arranged in pairs at different pitches in the channel direction, allowing each plate to face the X-ray focal point while maintaining overall flatness across the wide detection range.
Solution Approach 2:
The patent introduces a new dimensional arrangement by forming grooves in front and rear supports at different pitches in the channel direction. This allows collimator plates to be positioned at angles that make them face the X-ray focal point, solving the flatness issue while maintaining wide detection range.
2Area of stationary object
If module type collimators are arranged to cover the entire detection surface, then the detection range is improved, but alignment cannot be performed and the X-ray focal point shifts due to mount surface instability
Solution Approach 1:
Multiple collimator modules are arranged adjacent to each other along the channel direction to cover the entire detection surface. The modules are integrated into a unified structure with consistent groove arrangements, ensuring continuous X-ray focal point across all detector channels while maintaining stable mounting surfaces.
3Manufacturing precision
If collimator plates are inserted in grooves at different pitches to face the X-ray focal point, then the focal point alignment is improved, but the structure becomes more complex requiring front and rear supports
Solution Approach 1:
The front and rear supports serve multiple functions: they provide structural framework, hold grooves for collimator plate insertion, and position plates at correct pitches. The grooves themselves perform both mechanical support and alignment functions, reducing the need for additional complex positioning mechanisms.
Data Source
Figure 1A~1B
Figure 2A
Figure 2B~3
AI summary
The angle of each collimator plate (504) with respect to an X-ray focal point is determined by fitting the collimator plate in grooves (505) formed in upper and lower supports (500, 501) each having an integral structure. In addition, the warpage of each collimator plate is corrected and its flatness is maintained by fitting the periphery of the collimator plate which is on the X-ray detector side in a corresponding groove of an abutment plate (503) provided on the X-ray detection surface side of the upper and lower supports. Furthermore, each collimator plate is supported by the corresponding grooves of the upper and lower supports and the corresponding groove (506) of the abutment plate at at least three sides.