Annular Bearing Alignment Features for Imaging Iso-Center Accuracy
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Solution Overview
Problem
Current imaging systems face challenges in accurately aligning rotating components with the iso-center, leading to reduced image quality and radiation dose inefficiencies due to high machining costs and inherent inaccuracies in tight tolerance approaches.
Innovation Solution
An imaging system utilizing an annular bearing with alignment features to spatially align the detection system with the iso-center, decoupling the rotating gantry from the tolerance chain, allowing for reduced machining tolerances and more accurate alignment through complementary alignment features and an alignment device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tight tolerances are applied to bearing, rotating frame, and detection system interfaces to achieve accurate alignment, then alignment accuracy is improved, but manufacturing cost increases due to higher machining costs
Solution Approach 1:
The patent segments the alignment function into two independent parts: (1) the bearing provides a precisely machined mounting surface for the detection system, and (2) the rotating frame provides alignment features that interface with the bearing's precision surface. This segmentation allows the precision machining to be concentrated on the bearing only, rather than requiring tight tolerances on all interfacing surfaces of the rotating frame and detection system, thereby reducing overall manufacturing cost while maintaining alignment accuracy.
Solution Approach 2:
The patent replaces the traditional mechanical alignment approach (using multiple tightly toleranced mating surfaces between bearing, rotating frame, and detection system) with a simplified mechanical system where the bearing's precision surface serves as the primary alignment reference. The rotating frame's alignment pins engage with precision holes in the bearing, substituting complex multi-surface mechanical interfaces with a simpler pin-and-hole alignment mechanism that reduces machining requirements.
2Manufacturing precision
If tight tolerances are applied to component interfaces to achieve accurate alignment, then image quality is improved, but inherent inaccuracy remains due to manufacturing limitations and tolerance stack up
Solution Approach 1:
The patent extracts the precision alignment function from the rotating frame and concentrates it entirely in the bearing. The bearing is machined with a precise concentric circle or cylinder that serves as the sole alignment reference for the detection system. By taking out the alignment responsibility from the rotating frame's multiple interfaces and concentrating it in the bearing's single precision surface, the patent eliminates tolerance stack-up across multiple components and ensures consistent alignment regardless of manufacturing variations in the rotating frame or detection system mounting surfaces.
3Manufacturing precision
If tight tolerances are applied to component interfaces, then alignment accuracy is improved, but radiation dose efficiency decreases due to misalignment causing undetected x-rays
Solution Approach 1:
The patent performs alignment in advance by precisely machining the bearing's mounting surface and alignment features before assembly. The detection system is pre-aligned to the bearing's precision surface, ensuring that the x-ray tube focal spot, detection system, and rotating frame are all coaxial with the bearing center (iso-center) before the scanning process begins. This preliminary alignment action prevents misalignment during operation, ensuring that all x-rays traversing the subject are properly detected and eliminating radiation dose inefficiencies.
Data Source
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AI summary
An imaging system (100) includes an annular bearing (404) with an iso-center (406). The annular bearing includes a stationary side (4041) and a rotatable side (4042) with at least one alignment feature (420). The imaging system further includes a rotating gantry (410) mechanically coupled to the rotatable side. The imaging system further includes an imaging component (412, 416, 418). The imaging components includes at least one complementary alignment feature (602, 804) that is complementary to the at least one alignment feature (420, 802, 1200) of the rotatable side. The rotating gantry is between the imaging component and the rotatable side, and the imaging component is aligned with the iso-center through the at least one alignment feature and the at least one complementary alignment feature.