Computed Tomography Collimator Beam Shaping
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Solution Overview
Problem
Computed tomography images reconstructed from sparsely sampled projection data often have reduced image quality due to incomplete radiation usage and increased scattered radiation, leading to noise and artifacts.
Innovation Solution
A projection data acquisition apparatus that generates pulsed radiation beams with varying shapes using a collimator to block or attenuate the radiation, reducing scattered radiation and improving image quality by using a correction unit to process scatter data, while adhering to spatial radiation dose constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If sparsely sampled projection data is used to reduce radiation dose, then radiation dose is reduced, but image quality deteriorates due to incomplete sampling and increased scattered radiation
Solution Approach 1:
The patent applies local quality by using a collimator to selectively block radiation in specific angular ranges, creating different beam shapes at different acquisition positions. This allows the system to optimize radiation usage locally - using full beams where needed and restricted beams where scattered radiation is problematic - thereby improving image quality in specific regions without uniformly increasing the overall radiation dose.
Solution Approach 2:
The patent employs dynamic beam shaping through a movable collimator that adjusts the radiation beam shape adaptively at different acquisition positions along the trajectory. This dynamic adjustment allows the system to optimize the balance between radiation dose and image quality for each specific position, using smaller beams when scattered radiation would be problematic and larger beams when complete sampling is needed.
2Object-generated harmful factors
If smaller pulsed radiation beams are used at certain acquisition positions, then scattered radiation is reduced and signal-to-noise ratio is increased, but complete radiation sampling is compromised
Solution Approach 1:
The patent applies partial action by using smaller pulsed radiation beams at selected acquisition positions rather than uniformly using full beams throughout. This partial blocking strategy is implemented selectively - using restricted beams at positions where scattered radiation would degrade image quality, while using complete beams at positions where full sampling is critical. The collimator dynamically adjusts to apply the appropriate level of blocking at each position, achieving optimal balance between reducing scattered radiation and maintaining data completeness.
3Object-generated harmful factors
If a collimator is used to shape the radiation beam, then scattered radiation is reduced, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the collimator as a multi-functional component that simultaneously performs beam shaping, scattered radiation reduction, and adaptive adjustment across multiple acquisition positions. The single collimator structure serves multiple purposes: it blocks radiation in specific angular ranges, dynamically adapts to different positions along the trajectory, and works in conjunction with the pulsed radiation source to achieve optimal imaging conditions throughout the scan, thereby reducing scattered radiation without proportionally increasing overall system complexity.
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 solution enhances the signal-to-noise ratio and improves the quality of computed tomography images by reducing scattered radiation and noise, while maintaining controlled radiation doses, thus achieving better image reconstruction.
Implementation Method 1
the collimator is adapted to partially block the radiation beam such that a shadowed region and a non-shadowed region are generated on the detection device
Implementation Method 2
the detection device is adapted to generate the projection data based on the pulsed radiation beam directed onto the non-shadowed region and to generate scatter data based on radiation, which has been scattered onto the shadowed region
Implementation Method 3
the projection data acquisition apparatus further comprises a correction unit for correcting the generated projection data based on the scatter data
Data Source
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AI summary
The invention relates to a projection data acquisition apparatus (31) for acquiring projection data. The projection data acquisition apparatus comprises a radiation device (32) for generating a pulsed radiation beam (4) for traversing an object and a detection device (6) for generating projection data being indicative of the pulsed radiation beam (4) at different acquisition positions, wherein the radiation device (32) is adapted to generate the pulsed radiation beam (4) such that at different acquisition positions the pulsed radiation beam (4) has different shapes, i.e. is differently blocked and/or attenuated. Thus, not the complete radiation providable by the radiation device is used at each acquisition position, but at least at some acquisition positions only a smaller pulsed radiation beam is used. This can lead to less scattered radiation and hence to improved projection data and an improved computed tomography image, which may be reconstructed based on the acquired projection data.