Variable View Duration CT Imaging for Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Computed tomography (CT) imaging systems face challenges in achieving desired image quality for large patients or low-dose scans due to limitations in radiation flux, leading to artifacts, photon starvation, and electronic noise, which affect image quality and radiation dose management.
Innovation Solution
The system adjusts the view duration of CT imaging data acquisition by varying the duration of views as a function of rotation angle or view angle, allowing for improved signal-to-noise ratio and image quality without increasing radiation dose, by employing a CT acquisition unit with an X-ray source and detector that rotate around the object, and a processing unit that controls the view duration to optimize imaging information collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If automatic exposure control modulates radiation flux to achieve desired image quality, then image quality is improved, but for large patients the system reaches flux limits and cannot generate enough radiation, introducing low flux artifacts
Solution Approach 1:
The patent applies dynamics by making the view duration variable rather than fixed. The processing unit dynamically adjusts the view duration based on the projection data characteristics and desired image quality, allowing the system to adapt to different patient sizes and attenuation levels. This enables the system to maintain adequate signal accumulation time even when radiation flux is limited, resolving the contradiction between achieving desired image quality and being constrained by maximum flux capacity.
Solution Approach 2:
The patent changes the parameter of view duration from a fixed value to a variable parameter that can be adjusted based on imaging conditions. By modifying this temporal parameter, the system can compensate for insufficient radiation flux in large patients, allowing adequate signal accumulation without increasing the maximum flux capacity or compromising image quality.
2Quantity of substance
If low dose scans are used to reduce radiation, then radiation dose is reduced, but photon starvation and electronic noise dominate the measurements, adversely affecting imaging
Solution Approach 1:
The system dynamically adjusts view duration based on the balance between radiation dose and image quality requirements. By extending the view duration when operating at low doses, the system compensates for photon starvation and electronic noise, maintaining measurement precision while keeping radiation dose low. This dynamic adjustment resolves the contradiction between reducing radiation dose and maintaining imaging quality.
Solution Approach 2:
The patent ensures continuous and adequate signal accumulation by extending the view duration during low-dose scans. This continuous action allows sufficient photons to be detected throughout the extended acquisition period, preventing photon starvation and reducing the impact of electronic noise, thereby maintaining imaging quality while using low radiation doses.
3Device complexity
If uniform view duration is used for all views, then the acquisition process is simple, but the system cannot optimize signal-to-noise ratio for different viewing angles or patient characteristics
Solution Approach 1:
The patent applies local quality by making the view duration specific to each view's imaging conditions rather than using a uniform duration for all views. The processing unit evaluates the projection data characteristics for each view and adjusts the duration accordingly, optimizing the signal-to-noise ratio for each specific viewing angle and patient region. This localized optimization resolves the contradiction between acquisition simplicity and measurement precision.
Solution Approach 2:
The system transitions from a static, uniform view duration to a dynamic, variable view duration that adapts to local imaging conditions. This dynamic adjustment allows each view to have optimized acquisition time based on its specific requirements, significantly improving signal-to-noise ratio while adding manageable complexity to the acquisition process through automated processing unit control.
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 enhances image quality while maintaining a limited radiation dose, improving the signal-to-noise ratio and reducing noise in images, thereby addressing the limitations of existing automatic exposure control systems.
Implementation Method 1
an X-ray source may be rotated around an object to obtain imaging information. X-rays from the source attenuated by the object may be collected or detected by a detector
Data Source
AI summary
An imaging system includes a computed tomography (CT) acquisition unit and a processing unit. The CT acquisition unit includes an X-ray source and a CT detector configured to collect CT imaging data of an object to be imaged. The X-ray source and CT detector are configured to be rotated about the object to be imaged and to collect a series of views of the object as the X-ray source and CT detector rotate about the object to be imaged. The processing unit is operably coupled to the CT acquisition unit and configured to control the CT acquisition unit to vary a view duration for the views of the series. The view duration for a particular view defines an imaging information acquisition period for the particular view, wherein the series of views includes a first group of views having a first view duration and a second group of views having a second view duration that is different than the first view duration.