Spherical CT Detector Module Support with Symmetric Steps
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Solution Overview
Problem
Current CT detectors face challenges in manufacturing large Z-coverage systems due to the need for massive mono-structures, which result in manufacturing flaws and image quality issues, especially when trying to image the heart in one rotation, requiring detectors with 256 slices and 1000 channels, leading to geometric gaps between mini-modules.
Innovation Solution
The solution involves fabricating a spherical CT detector using an array of module support structures with symmetrically disposed steps along the Z-axis, allowing detector modules to be positioned closer at the center, reducing gaps between modules, and using mini-modules aligned towards the focal spot, enabling precise collimation and improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a massive mono-structure detector is built to achieve 256 slices and 1000 channels for large Z-coverage, then the detector coverage area is improved, but manufacturing flaws and image quality issues increase
Solution Approach 1:
The detector is divided into multiple mini-modules that can be independently manufactured and tested. Each mini-module contains a subset of detector elements, allowing for reduced complexity in each unit and easier quality control. The mini-modules are then assembled to form the complete detector array, maintaining large coverage while improving manufacturing reliability.
Solution Approach 2:
Multiple mini-modules are nested or stacked together to form the complete detector structure. The mini-modules are arranged in a configured manner that allows them to be positioned at different locations on the detector arc, creating a nested assembly that achieves large Z-coverage through combination of smaller, manageable units.
2Ease of manufacture
If mini-modules are placed on the arc to achieve modular construction, then ease of manufacture is improved, but geometric gaps occur between modules
Solution Approach 1:
The support structure includes varying heights at different locations to compensate for the arc geometry. Specifically, the support structure has a first height at certain locations and a second height at other locations, creating a non-uniform structure that locally adjusts the detector module positions to eliminate gaps while maintaining modular construction.
Solution Approach 2:
The detector elements are arranged on a curved arc surface rather than a flat plane. The support structure is designed with varying heights that correspond to the curvature of the arc, allowing the mini-modules to be positioned at the correct radial distance from the focal spot. This curved arrangement eliminates geometric gaps between modules while maintaining ease of modular assembly.
3Speed
If the detector is designed to image the heart in one rotation, then imaging speed is improved, but the detector size and complexity increase
Solution Approach 1:
The detector is segmented into multiple mini-modules that can be independently manufactured and assembled. This segmentation allows the detector to achieve large Z-coverage (256 slices) through combination of smaller units rather than building a single massive structure, thereby reducing overall complexity while maintaining the capability to image the heart in one rotation.
Solution Approach 2:
The detector elements are arranged in three-dimensional space on a curved arc surface rather than in a simple two-dimensional plane. The support structure with varying heights creates a three-dimensional configuration that allows the detector to cover a large Z-range while maintaining compact radial dimensions, effectively utilizing spatial arrangement to achieve high-speed imaging without proportional increase in complexity.
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 construction of reliable, high-slice CT detectors with reduced gaps and improved image quality by enabling precise alignment and reparability of mini-modules, facilitating the imaging of large areas like the heart in a single rotation without significant manufacturing flaws.
Implementation Method 1
The material used in these detectors generally use scintillation crystal/photodiode arrays, where the scintillation crystal absorbs X rays and converts the absorbed energy into visible light
Implementation Method 2
A photodiode is used to convert the light to an electric current
Implementation Method 3
The detector pixels include collimating elements that are directed toward the focal spot. However, collimation may need to account for the arc in not only the channel direction, but in the Z or slice direction, as well
Data Source
AI summary
A CT system includes a rotatable gantry having, an x-ray tube having a focal spot, and a detector assembly positioned to receive the x-rays that pass through the object. The detector assembly includes an array of module support structures positioned along a channel direction, each module support structure having module support surfaces extending along the Z-axis, the array including a first module support structure and a second module support structure that are side-by-side, and a plurality of detector modules positioned on each module support structure and having collimating elements that are generally aligned toward the focal spot. Each of the first and second module support structures includes two steps symmetrically disposed along the Z-axis, such that a first gap between the detector modules of the first and second module support structures at a center of each is less than a second gap formed at each step.