Collimator Module Alignment for Uniform X-ray CT Pitch
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Solution Overview
Problem
Conventional X-ray computed tomography (CT) apparatuses face challenges in manufacturing two-dimensional collimators with uniform thickness and pitch due to the alignment of multiple modules, leading to inconsistencies and increased pitch errors as the number of modules increases.
Innovation Solution
The implementation of a collimator unit comprising a supporter and a fixing unit that aligns and fixes collimator modules in a grid pattern, ensuring uniform thickness and pitch by using a collimator base with arc-shaped plates and modules with orthogonal collimator plates, and employing methods like grooves or engaging portions for precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple collimator modules are arranged and aligned to create a two-dimensional collimator, then the collimator can cover a larger area and eliminate scattered radiation from multiple directions, but the thickness and pitch of the collimator plates become non-uniform due to alignment errors and manufacturing tolerances
Solution Approach 1:
The collimator is divided into multiple independent modules, each with its own collimator plates arranged in a grid pattern. This segmentation allows each module to be manufactured separately with controlled thickness and pitch, then assembled into a larger two-dimensional collimator structure that maintains uniformity across the entire coverage area.
Solution Approach 2:
A support structure with positioning features (such as positioning holes and positioning protrusions) acts as an intermediary between collimator modules during assembly. This intermediary component ensures precise alignment and maintains uniform thickness and pitch across module boundaries, eliminating the non-uniformity that would otherwise result from direct alignment of multiple modules.
2Ease of manufacture
If collimator modules are assembled from separate components, then manufacturing and assembly become more flexible and easier, but pitch errors accumulate as the number of modules increases
Solution Approach 1:
Positioning features (positioning holes and positioning protrusions) are pre-formed on the support structure and collimator modules during manufacturing. These preliminary positioning elements ensure that when modules are assembled, they automatically align with the correct pitch, preventing error accumulation that would otherwise occur with manual alignment of multiple modules.
Solution Approach 2:
The support structure with integrated positioning features serves as an intermediary that mediates the relationship between collimator modules. This intermediary component transfers and maintains the correct pitch dimension across all modules, ensuring uniformity is preserved throughout the entire collimator assembly regardless of the number of modules used.
3Manufacturing precision
If a seamless assembly method is used for collimator plates, then uniform thickness and pitch can be achieved, but it is difficult to create collimators for all channels and slices simultaneously
Solution Approach 1:
The collimator system is segmented into multiple modules that can be independently manufactured with uniform thickness and pitch using seamless assembly methods for each module. These standardized modules can then be assembled in different configurations to accommodate various channel and slice requirements, providing both precision and versatility.
Solution Approach 2:
The collimator modules are designed with universal interfaces and standardized dimensions, allowing the same module design to be used across multiple channels and slices. This universality enables the system to maintain uniform thickness and pitch while adapting to different collimator configurations and coverage requirements.
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 allows for the creation of a collimator with uniform thickness and pitch, reducing artifacts in images and improving the accuracy of radiation detection by ensuring consistent alignment of collimator modules, thereby enhancing image quality.
Implementation Method 1
The collimator unit eliminates scattered radiation from X-rays that are incident on the radiation detector
Implementation Method 2
The collimator includes a one-dimensional collimator that eliminates scattered radiation from a channel direction and a two-dimensional collimator that eliminates scattered radiation from the channel direction and a slice direction
Data Source
AI summary
An X-ray CT apparatus according to an embodiment includes an X-ray detector and a collimator unit. The X-ray detector detects X-rays that have passed through a subject. The collimator unit eliminates scattered radiation from X-rays that are incident on the X-ray detector. The collimator unit includes a plurality of collimator modules, a supporter, and a fixing unit. The plurality of collimator modules each includes a plurality of first collimator plates arranged in a grid along a channel direction and a slice direction that are orthogonal to each other. The supporter supports the collimator modules such that the collimator modules are aligned in a plurality of straight lines along the channel direction and in a plurality of straight lines along the slice direction. The fixing unit is provided to the supporter and fixes positions of the collimator modules in the channel direction and the slice direction.