Dynamic CT Filter for Varying Subject Adaptation
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Solution Overview
Problem
Conventional CT scanners with static bowtie filters struggle to adapt to varying subject sizes and orientations, leading to inadequate photon flux at the edges, which compromises image fidelity due to insufficient calibration and inconsistent filtering profiles.
Innovation Solution
A dynamically adjustable filter with two moveable regions of uniform thickness and homogeneity, positioned based on the subject's shape and orientation, to optimize radiation attenuation and calibration across the detector array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a static bowtie filter is used to attenuate peripheral rays, then radiation efficiency is improved, but the filter cannot adapt to varying subject sizes and orientations, leading to inadequate photon flux at the edges
Solution Approach 1:
The patent applies the dynamics principle by replacing the static bowtie filter with a dynamic filter that can change its attenuation profile in real-time. The filter is divided into multiple independently controllable regions (first and second regions) that can adjust their attenuation levels dynamically. This allows the filter to adapt to varying subject sizes and orientations while maintaining radiation efficiency, resolving the contradiction between fixed filtering performance and adaptability.
Solution Approach 2:
The patent implements parameter changes by allowing the attenuation characteristics of the filter regions to be adjusted dynamically. The first and second regions can change their attenuation parameters (such as material density or thickness) based on the detected subject characteristics. This enables the filter to optimize photon flux distribution for different scanning scenarios, maintaining both radiation efficiency and adaptability.
2Device complexity
If a static bowtie filter is used, then the filter structure is simple, but calibration becomes difficult when subjects are positioned off-center or have varying profiles
Solution Approach 1:
The patent applies segmentation by dividing the bowtie filter into multiple independent regions (first region and second region) that can be controlled separately. Each region can be independently adjusted and calibrated, which simplifies the overall calibration process compared to a monolithic static filter. This segmentation allows precise calibration for off-center positions and varying subject profiles while maintaining reasonable structural complexity.
Solution Approach 2:
The dynamic nature of the filter allows real-time adjustment during scanning, enabling the system to compensate for off-center positioning and varying subject profiles. The filter can dynamically reconfigure its attenuation profile to match the actual scanning conditions, improving calibration precision without requiring complex pre-calibration procedures for every possible scenario.
3Loss of energy
If peripheral rays are heavily filtered to reduce flux, then radiation efficiency improves, but photon flux at the edges decreases, compromising image fidelity
Solution Approach 1:
The patent applies local quality by implementing different attenuation characteristics in different regions of the filter. The first and second regions can be configured to provide different levels of attenuation based on the specific scanning requirements. This allows optimized filtering in peripheral regions while maintaining adequate photon flux in critical areas, thereby preserving image fidelity while improving overall radiation efficiency.
Solution Approach 2:
The dynamic adjustment capability allows the filter to change its attenuation parameters in real-time based on the detected subject and scanning conditions. This enables the system to optimize the balance between radiation efficiency and image fidelity by adjusting the attenuation level dynamically, rather than using a fixed heavy filtering profile that would compromise edge 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
Enhances image quality by ensuring precise calibration and consistent filtering, maintaining high photon flux across the detector array, even for subjects of varying sizes and orientations, thereby improving diagnostic image quality.
Implementation Method 1
a filter, disposed between the source and the examination region, that filters peripheral regions of the emitted radiation
Data Source
Figure 1(A)~2(C)
Figure 3
Figure 4~5
AI summary
An imaging system including a source (310) having a focal spot (406) that emits a radiation beam that traverses an examination region, a radiation sensitive detector array (316) having a plurality of pixels that detects radiation traversing the examination region and generates projection data indicative of the detected radiation, and a filter (314), disposed between the source and the examination region, that filters peripheral regions of the emitted radiation, wherein the filter includes two separate and moveable regions (402), each region having a substantially same thickness and constant homogeneity.