CT Control Scan Parameter Selection for Needle Artifact Reduction
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Solution Overview
Problem
Existing computed tomography scanner arrangements face challenges in reconstructing clear images of control scans due to image artifacts caused by metal objects like needles, which result in dark streaks and signal attenuation, leading to parts of the object disappearing in the images.
Innovation Solution
A method and system that utilize an evaluation model to assess the risk of image artifacts by analyzing object path data and control scan data, adjusting parameters such as radiation dose, gantry orientation, and tube settings to minimize artifact risk, using machine learning algorithms and geometric optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the dose of computed tomography scans is reduced to a low level to minimize radiation exposure, then patient safety is improved, but image quality deteriorates and objects may disappear in the images
Solution Approach 1:
The patent applies local quality by differentiating between different regions in the image and applying different reconstruction techniques. Specifically, it uses a dual-stage reconstruction approach where a first reconstruction is performed for the entire image, and a second, more sophisticated reconstruction is applied specifically to regions containing objects (needles). This allows optimized image quality in critical areas without requiring high dose across the entire scan volume.
Solution Approach 2:
The patent employs parameter changes by utilizing multiple reconstruction parameters and algorithms. It transforms the reconstruction process from a single fixed-parameter approach to a multi-parameter approach that includes iterative reconstruction, resolution recovery, and artifact reduction techniques. This allows the system to maintain image quality at low doses by dynamically adjusting reconstruction parameters based on the specific imaging conditions and object characteristics.
2Measurement precision
If scan parameters are optimized to maintain image quality at low dose, then measurement precision is improved, but the complexity of the scanning and reconstruction process increases
Solution Approach 1:
The patent applies segmentation by dividing the reconstruction process into distinct stages and regions. It segments the image into regions with objects and regions without objects, applying different reconstruction strategies to each. The process is segmented into a first reconstruction stage for initial image formation and a second reconstruction stage for refined object visualization. This segmentation manages complexity by handling different regions with appropriate levels of processing intensity.
Solution Approach 2:
The patent employs preliminary action by performing a first reconstruction before the second, more complex reconstruction. This initial reconstruction provides a baseline image that guides subsequent processing, allowing the system to identify object locations and apply targeted refinement only where needed. This preliminary step simplifies the overall process by preparing the data structure for more efficient subsequent processing.
3Ease of operation
If objects are imaged along paths completely within the scan plane for ergonomic reasons, then ease of operation is improved, but image artifacts increase due to beam-hardening and scatter
Solution Approach 1:
The patent converts the harmful effect of objects being within the scan plane into a benefit by using the known object positions and paths to guide the reconstruction process. Instead of treating artifacts as unwanted side effects to be eliminated, the system uses object location information from the first reconstruction to target and correct artifacts in the second reconstruction. This transforms the problem of artifacts into an opportunity for focused improvement.
Solution Approach 2:
The patent implements feedback by using the results of the first reconstruction to inform and guide the second reconstruction process. The object positions, paths, and artifact patterns identified in the initial reconstruction provide feedback that directs the application of resolution recovery and artifact reduction techniques in the subsequent reconstruction. This feedback loop allows the system to adaptively optimize image quality based on actual imaging conditions.
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
The method effectively reduces the risk of image artifacts by optimizing scan parameters, ensuring accurate reconstruction of object positions in computed tomography images without vanishing objects.
Implementation Method 1
x-rays are attenuated along the whole object which results in a quite low primary signal
Implementation Method 2
Those artifacts are caused by the physical effects of beam-hardening and scatter
Implementation Method 3
Those artifacts are caused by the physical effects of beam-hardening and scatter
Data Source
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AI summary
Computer-implemented method for providing parameter data for carrying out at least one control scan with a computed tomography scanner arrangement, comprising: receiving object path data, at least comprising geometric information about a planned movement path of an object; receiving predefined control scan data, at least comprising information about the position and orientation of at least one scan plane of at least one planned control scan for controlling the movement path of the object; receiving an evaluation model configured to provide parameter data for performing the at least one control scan at least depending on the received object path data and the received control scan data; applying the evaluation model and providing parameter data for performing the at least one control scan, wherein at least the object path data and the predefined control scan data are input data of the evaluation model.