CT Detector Module Alignment via Modular Mounting
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Solution Overview
Problem
The alignment of detector modules in computed tomography (CT) systems is challenging due to increased length and complexity, leading to tolerance stack-up issues during assembly, which is difficult to control both in manufacturing and in-field, especially when replacing failed modules in installed systems.
Innovation Solution
A detector sub-assembly with a support structure featuring Y-axis and X-axis mount surfaces and apertures, along with a mounting screw with a smaller outer diameter than the aperture, allows for precise alignment and attachment of mini-modules, enabling easier assembly and replacement without disassembling the entire detector assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the detector length is increased to cover more slices (256 or more), then the imaging coverage and productivity are improved, but the alignment precision and manufacturing complexity deteriorate due to tolerance stack-up
Solution Approach 1:
The detector is divided into multiple independent mini-modules along the Z-axis, each with its own mount block and alignment features. This segmentation allows each module to be manufactured and aligned separately, preventing tolerance accumulation across the entire detector length while still achieving large total coverage when modules are assembled together.
2Manufacturing precision
If the detector is assembled as a monolithic structure to ensure alignment, then the manufacturing precision is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
Rather than assembling a single complex monolithic detector, the system uses multiple standardized mini-modules with identical mount blocks and alignment features. This reduces assembly complexity by making modules interchangeable and simplifies manufacturing while maintaining alignment precision through repeated modular units.
Solution Approach 2:
Each mini-module is pre-assembled with its mount block and alignment features before being integrated into the complete detector. This preliminary assembly ensures proper alignment is built into each module independently, reducing the complexity of final detector assembly while maintaining precision.
3Reliability
If the entire detector assembly is removed to replace a failed module, then the reliability is improved by ensuring proper alignment, but the loss of time and productivity increase
Solution Approach 1:
The detector is segmented into independently replaceable mini-modules, allowing failure isolation to the module level rather than requiring complete detector removal. The standardized mount blocks and alignment features enable quick module replacement while maintaining alignment reliability through the modular design.
Solution Approach 2:
Failed mini-modules can be quickly removed and replaced with new or refurbished modules without affecting the rest of the detector assembly. The standardized interface and alignment features allow for rapid exchange, minimizing downtime while ensuring proper alignment through the modular architecture.
4Manufacturing precision
If tight tolerances are enforced during module assembly to control stack-up, then the manufacturing precision is improved, but the ease of manufacture and assembly deteriorate
Solution Approach 1:
By segmenting the detector into mini-modules with individual mount blocks, the tolerance stack-up problem is contained within each module rather than accumulating across the entire detector. This allows for practical tolerance control at the module level while maintaining ease of manufacture through standardized, repeatable assembly processes.
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 solution improves the alignment and assembly efficiency of CT detector modules, reducing manufacturing and maintenance costs by allowing for precise positioning and easy replacement of modules within the CT system, minimizing downtime and operational expenses.
Implementation Method 1
a mounting screw having an outer diameter that is smaller than an inner diameter of the aperture and passing through the aperture and into the second aperture when the Y-axis planar surface is on the Y-axis mount surface
Data Source
AI summary
A detector sub-assembly for a CT system includes a detector module that includes a mount block having a top planar surface, a Y-axis planar surface that is parallel with the top planar surface, an X-axis planar surface that is orthogonal to the first Y-axis planar surface, and an aperture passing through the X-axis planar surface. The module includes a substrate having a pixelated photodiode positioned thereon, and a two-dimensional anti-scatter grid (ASG) positioned on the pixelated photodiode. The detector sub-assembly includes a support structure including a Y-axis mount surface and an X-axis mount surface, and a second aperture passing through the X-axis mount surface, a mounting screw having an outer diameter that is smaller than an inner diameter of the aperture and passing through the aperture and into the second aperture when the Y-axis planar surface is on the Y-axis mount surface.