Segmented Aperture Edge Profile for CT X-ray Collimator Beam Shaping
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Solution Overview
Problem
Existing CT systems face challenges in efficiently shaping x-ray beams to match curved detectors, leading to beam distortion and increased x-ray exposure due to un-used portions of the beam, which results in reduced dose efficiency and space constraints.
Innovation Solution
A planar collimator with a specifically designed aperture edge profile that includes flat plates, where the central portion corresponds to the central detector and the end portions correspond to the detector ends, providing a discontinuous profile to optimize beam projection and reduce unnecessary exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a substantially planar collimator with a generally rectangular aperture profile is used to shape an x-ray beam for a curved detector, then the collimator structure is simple and compact, but the beam projection coverage is distorted and results in un-used x-ray portions causing patient overdose
Solution Approach 1:
The aperture edge is divided into multiple segments: a first end portion, a second end portion, and a central portion. Each segment has a different profile configuration. The end portions have profiles that project beyond the detector edges to ensure full coverage, while the central portion has a profile that matches the detector curvature to eliminate un-used beam portions and reduce patient overdose.
Solution Approach 2:
Different portions of the aperture edge are given different geometric properties tailored to their specific function. The end portions use one profile type optimized for detector edge coverage, while the central portion uses a different profile type optimized for matching the detector's curved surface, thereby eliminating waste beam portions in the central region.
2Object-affected harmful factors
If a curved collimator is used instead of a substantially planar collimator to match the curved detector, then the beam projection coverage is improved, but the space occupied by the collimator increases significantly
Solution Approach 1:
The aperture edge incorporates curved profiles that match the detector's curved surface geometry. Specifically, the central portion and end portions have profiles designed to conform to the arc of the curved detector, ensuring optimal beam projection coverage without requiring the entire collimator structure to be curved.
Solution Approach 2:
The aperture edge is segmented into different profile types (curved central portion, curved end portions) that together achieve comprehensive detector coverage. This segmentation allows the collimator to maintain a compact planar form factor while delivering curved-detector-optimized beam shaping through its aperture design.
3Loss of energy
If linearly ramped apertures are used to reduce overdose compared to rectilinear shapes, then some dose efficiency is improved, but un-used x-ray beam portions still extend beyond the usable detector area
Solution Approach 1:
The aperture edge uses different profile characteristics in different regions. The end portions have profiles that extend beyond the detector to ensure complete coverage of the detector edges, while the central portion has a profile that precisely matches the detector curvature to eliminate un-used beam portions, thereby optimizing dose efficiency throughout the entire detector area.
Solution Approach 2:
The aperture is divided into functional segments with different profile types. The central portion segment is designed to eliminate waste beam portions for optimal dose efficiency, while the end portion segments are designed to ensure complete detector edge coverage, achieving both goals simultaneously through segmentation.
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 design improves beam shaping and dosage management, reduces x-ray overdose, and allows for a more compact form factor, enhancing the efficiency and space utilization of CT systems.
Implementation Method 1
The collimator includes an x-ray blocking surface that comprises one or more generally flat plates defining an aperture edge of the aperture
Implementation Method 2
the aperture allows x-ray transmission therethrough
Data Source
AI summary
A collimator includes an x-ray blocking surface including one or more generally flat plates defining an aperture edge. The aperture edge includes a first end portion including a first end of the aperture edge, a second end portion including a second end of the aperture edge, and a central portion including a center of the aperture edge. The first end portion of the aperture edge corresponds to a first end portion of a detector, the second end portion of the aperture edge corresponds to a second end portion of the detector, and the central portion of the aperture edge corresponds to a central portion of the detector. A profile of the aperture edge is discontinuous at a point between the first end of the aperture edge and the center of the aperture edge.