Dynamic Collimation for Digital Tilt CT Radiation Reduction
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Solution Overview
Problem
Conventional CT imaging modalities require mechanical tilting of the gantry to generate non-perpendicular image slices, which is costly and complex, and digital tilt techniques only represent a fraction of the object, leading to unnecessary radiation exposure.
Innovation Solution
A CT imaging modality with a pre-object collimator that dynamically adjusts radiation attenuation in the fan-angle direction during the examination, allowing for the generation of tilted images without mechanical tilting, thereby optimizing radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If mechanical tilt of the gantry is used to generate non-perpendicular image slices, then the image orientation requirement is satisfied, but the device complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical gantry tilt system with a digital image processing approach. Instead of physically tilting the gantry to achieve non-perpendicular image slices, the system uses computational methods to generate tilted images from standard axial CT data, eliminating the need for complex mechanical tilt mechanisms while maintaining the desired image orientation.
Solution Approach 2:
The patent changes the parameter space from physical gantry orientation to digital image reconstruction parameters. By adjusting reconstruction parameters during image processing rather than changing the physical geometry of the scanning system, the system achieves varied image orientations without mechanical modifications.
2Device complexity
If digital tilt technique is used to avoid mechanical tilting, then device complexity is reduced, but radiation exposure increases because only a fraction of the object is represented in the tilted image
Solution Approach 1:
The patent applies local quality by selectively attenuating radiation in specific regions of the fan beam. Instead of uniformly exposing the entire object, the system uses dynamic collimation to concentrate radiation only on the portion of the object that will be represented in the final tilted image, reducing unnecessary radiation exposure to other areas.
Solution Approach 2:
The patent introduces dynamic collimation that adjusts the fan beam attenuation in real-time during the scanning process. The collimator dynamically modifies the radiation distribution based on the desired tilted image geometry, allowing optimal radiation utilization while minimizing exposure to areas not needed for the final image.
3Object-affected harmful factors
If dynamic collimation adjustment is implemented, then radiation exposure is reduced, but device complexity increases due to the collimator adjustment mechanism
Solution Approach 1:
The patent makes the collimator system multi-functional by integrating it with the existing CT scanner components. The dynamic collimator works in conjunction with the radiation source and detector array, serving both radiation control and image quality optimization functions, thereby reducing the need for separate dedicated systems.
Solution Approach 2:
The system incorporates feedback mechanisms where the collimator adjustment is controlled based on real-time information from the scanning process. The dynamic collimator receives feedback about the desired image geometry and adjusts radiation attenuation accordingly, optimizing the balance between radiation reduction and image quality without requiring overly complex manual intervention.
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 reduces radiation exposure to the object by selectively attenuating radiation in areas not intended for image reconstruction, improving the efficiency of image generation and reducing the dose applied to the object.
Implementation Method 1
a pre-object collimator configured to dynamically adjust, in a fan-angle direction, attenuation of emitted radiation during an examination of an object
Data Source
AI summary
Among other things, one or more systems and/or techniques are described for dynamically adjusting, in a fan-angle direction, attenuation of radiation during an examination of an object such that portions of the object that are not represented in resulting (tilted/targeted) images of the object are exposed to less radiation than portions of the object that are represented in resulting (tilted/targeted) images of the object. As a rotating gantry is rotated, blades of a pre-object collimator are dynamically repositioned to selectively attenuate emitted radiation. A collimator adjustment component may be configured to determine how to reposition the blades based at least in part upon at least one of a desired tilt of the resulting (tilted) image(s), a translational position of the object, and a gantry rotation angle, for example.