X-ray CT Gantry Vibration Assessment via Image Artifacts
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Solution Overview
Problem
Conventional methods for measuring gantry vibration in X-ray CT scanners do not always accurately assess its impact on image quality, as the relationship between vibration frequency and image artifacts is not straightforward, and require large equipment for multi-directional measurements.
Innovation Solution
An X-ray CT scanner system that includes a gantry unit, reconstruction unit, extraction unit, and output unit, which uses a phantom to evaluate gantry vibration by generating a CT value profile and frequency spectrum, allowing for quantitative assessment of vibration's impact on image quality and identification of its causes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional vibration measurement methods are used to directly measure gantry displacement, then vibration values can be obtained, but the measurement results do not accurately reflect the actual influence on image quality and require large measurement equipment
Solution Approach 1:
The patent uses image data as a copy or proxy to indirectly measure vibration effects. Instead of directly measuring gantry displacement with complex equipment, the system analyzes artifacts in reconstructed images to infer vibration characteristics. The artifact information serves as a copy of the vibration effect, allowing accurate assessment without large measurement devices.
Solution Approach 2:
The patent replaces mechanical vibration measurement systems with an image-based analysis system. Instead of using mechanical sensors and large measurement equipment to detect gantry displacement, the system uses computational analysis of image artifacts to determine vibration influence, substituting a mechanical measurement approach with an information-processing approach.
2Reliability
If multi-directional vibration measurements are performed to comprehensively assess gantry vibration, then complete vibration data can be obtained, but large equipment is required and measurement complexity increases
Solution Approach 1:
The patent makes the image reconstruction system serve multiple functions: it not only creates diagnostic images but also simultaneously performs vibration assessment. The same imaging hardware and processing software that generate medical images are also used to detect and analyze vibration artifacts, eliminating the need for separate dedicated measurement equipment.
Solution Approach 2:
The system performs self-diagnosis by using its own image data to assess its operational stability. The gantry vibration measurement system uses the images it generates to automatically detect vibration artifacts and evaluate the stability of the imaging system, without requiring external measurement devices.
3Measurement precision
If high-frequency vibration measurements are performed with small amplitude, then detailed vibration characteristics can be captured, but noticeable artifacts occur in reconstructed images
Solution Approach 1:
The patent converts the harmful vibration artifacts into beneficial measurement signals. Instead of treating image artifacts as unwanted noise to be eliminated, the system uses them as informative indicators of vibration characteristics. The artifacts, which were previously considered harmful, now serve as the basis for quantifying and analyzing gantry vibration.
Data Source
AI summary
According to one embodiment, an X-ray CT scanner includes a gantry unit, a reconstruction unit, an extraction unit, and an output unit. The gantry unit includes an X-ray source and an X-ray detector and is configured to rotate the source and the detector. The reconstruction unit generates reconstruction image data by using data acquired by the detector. The extraction unit extracts, when using a predetermined phantom as the object, pixel values of pixels existing on a locus surrounding a tomographic image of the phantom contained in reconstruction image data generated by the reconstruction unit based on data acquired by the detector. The output unit outputs an extraction result obtained by the extraction unit or information obtained based on the extraction result.