Dynamic Post-Patient Filter for CT Scanners
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Solution Overview
Problem
Conventional bowtie filters in CT scanners are not adaptable to varying subject shapes and orientations, leading to inadequate x-ray flux at the periphery, which can decrease the fidelity of detector output and hinder the generation of diagnostically valuable images.
Innovation Solution
A dynamic post-patient filter system with adjustable filter segments that move in front of the detector array to selectively filter unattenuated and peripheral radiation based on the subject's shape, ensuring optimal x-ray flux distribution during scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional bowtie filter is used, then radiation efficiency is improved, but adaptability to varying subject shapes deteriorates
Solution Approach 1:
The patent applies the dynamics principle by making the bowtie filter adjustable and reconfigurable to adapt to different subject shapes and sizes. The filter can be dynamically modified during scanning operations to match the specific anatomical profile being imaged, thereby maintaining optimal radiation efficiency across diverse scanning scenarios.
Solution Approach 2:
The patent implements parameter changes by allowing modification of the bowtie filter's physical parameters (such as attenuation coefficients and geometric configuration) to match varying subject characteristics. This enables the filter to optimize radiation distribution for different body types while maintaining efficiency.
2Device complexity
If a fixed bowtie filter profile is used, then device complexity is reduced, but image fidelity deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed filter profile to a dynamically adjustable profile that can be modified based on subject characteristics. This enables the system to maintain high image fidelity across different scanning scenarios without requiring multiple fixed filters, thus managing complexity effectively.
Solution Approach 2:
The patent implements universality by creating a single adjustable bowtie filter that can serve multiple functions across different subject types and scanning scenarios. This multi-functional approach eliminates the need for multiple specialized filters, reducing overall device complexity while maintaining image quality.
3Loss of energy
If peripheral rays are heavily filtered, then radiation efficiency is improved, but photon flux at beam edges deteriorates
Solution Approach 1:
The patent applies local quality by implementing differential filtering across different regions of the beam. The bowtie filter provides varied attenuation levels for different radial positions, allowing optimization of radiation efficiency in central regions while preserving adequate photon flux at peripheral regions to maintain image quality.
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 dynamic filter system enhances image fidelity by adjusting to the subject's shape and orientation, improving radiation efficiency and maintaining high diagnostic value of images by optimizing x-ray flux distribution.
Implementation Method 1
A dynamic post-patient filter including one or more filter segments is configured to selectively and dynamically move in front of the detector array between the detector array and the examination region and into and out of a path of the radiation beam illuminating the detector pixels during scanning an object or subject based on a shape of the object or subject, thereby filtering unattenuated radiation and radiation traversing a periphery of the object or subject
Data Source
AI summary
An imaging system includes a radiation source (310) configured to rotate around an examination region about a z-axis and having a focal spot that emits a radiation beam that traverses the examination region. The system further includes a radiation sensitive detector array (314) with a plurality of detector pixels that detects radiation traversing the examination region and generates projection data indicative of the detected radiation. The system further includes a dynamic post-patient filter (316) including one or more filter segments (402, 802, 902, 1004, 1102). The filter is configured to selectively and dynamically move in front of the detector array between the detector array and the examination region and into and out of a path of the radiation beam illuminating the detector pixels during scanning an object or subject based on a shape of the object or subject, thereby filtering unattenuated radiation and radiation traversing a periphery of the object or subject.