Static CT Scatter Measurement via Sequential Emitter Shadowing
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Solution Overview
Problem
Static CT devices face challenges in accurately determining scattered radiation distribution, leading to image artifacts due to the inability to irradiate detectors from different projection angles, which is not feasible with collimators designed for rotating CT devices.
Innovation Solution
A method and device for a static CT device with a stationary detector ring and emitter ring, where a subgroup of radiators are sequentially activated to generate X-ray fans, and absorbers create shadows within these fans to directly measure scattered radiation, allowing for patient-specific distribution determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If collimators are inserted between detector elements to reduce scattered radiation, then scattered radiation is reduced, but this solution is not applicable to static CT scanners where detectors are irradiated from lateral positions
Solution Approach 1:
Instead of blocking scattered radiation with collimators in the conventional path, the invention inverts the approach by using absorbers to create shadows that allow scattered radiation to reach detectors from lateral positions. This inverted shadow-based method enables static CT scanners to measure scattered radiation that would otherwise be blocked, making the solution adaptable to different scanner types while reducing harmful scattered radiation effects
Solution Approach 2:
The invention introduces absorbers as intermediary elements that create shadows between the X-ray source and detectors. These absorbers mediate the measurement process by blocking primary radiation while allowing scattered radiation to reach detectors, enabling scattered radiation measurement in static CT scanners without requiring rotating components
2Device complexity
If computational methods are used to determine scattered radiation distribution, then measurement complexity is reduced, but patient-specific scattered radiation distribution cannot be accurately determined
Solution Approach 1:
The system performs self-service by using its own detector array to measure scattered radiation distribution directly during the CT scan process. The same detectors that capture primary radiation also measure scattered radiation through the shadow technique, eliminating the need for separate measurement systems or complex computational models while achieving patient-specific accuracy
Solution Approach 2:
The invention changes the measurement parameter approach by directly measuring scattered radiation intensity distribution using absorber shadows rather than computing it from primary radiation data. This parameter change from computational estimation to direct measurement enables accurate patient-specific scattered radiation distribution determination while maintaining manageable system complexity
3Productivity
If scattered radiation is not corrected, then image acquisition is faster, but image realism deteriorates due to artifacts from scattered radiation
Solution Approach 1:
The system performs preliminary measurement of scattered radiation distribution using the absorber shadow technique before or during image acquisition. By measuring scattered radiation in advance with the same detector array, the system can correct image data subsequently without slowing down the overall acquisition process, maintaining both speed and image realism
Solution Approach 2:
The invention implements feedback by using measured scattered radiation distribution to correct primary radiation measurements. The detected scattered radiation values are fed back into the image reconstruction process to subtract scattered radiation contributions, improving image realism while maintaining acquisition efficiency through automated correction
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
Enables direct measurement and correction of scattered radiation during CT scans, improving image realism by subtracting scattered radiation intensity, thus reducing radiation exposure and enhancing image quality without increasing patient exposure.
Implementation Method 1
the emitter ring comprises a plurality of emitters, comprising the steps of sequentially activating one or two emitters from a subgroup of the plurality of emitters of the emitter ring to generate one or two beam fans of X-radiation
Implementation Method 2
generating an absorber shadow within the respectively generated beam fan by at least one absorber arranged in the beam fan
Implementation Method 3
detecting the X-radiation in the absorber shadow by the detectors of the detector ring each arranged in the absorber shadow and thereby acquiring measured values
Data Source
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AI summary
The present invention provides a method and a computed tomography device (1) for measuring a scatter radiation distribution in an object (3) which is arranged in the computed tomography device (1) with a stationary detector ring (7) and a stationary source ring (4). The detector ring (7) comprises a plurality of detectors (8) and the source ring (4) comprises a plurality of sources (5).The method comprises the following steps: - Sequential activation (101) of one or two emitters (5) from a subgroup of the plurality of emitters (6) of the emitter ring (4), to generate one or two beam fans (9) of X-rays, - Generation of an absorber shadow (102) within the respective generated beam fan (9) by at least one absorber (10) arranged in the beam fan (9), - Detection of the X-rays (103) in the absorber shadow (11) by the detectors (8) of the detector ring (7) arranged in the respective absorber shadow (11) and thereby acquisition of measured values, and - Calculation of the scattered beam distribution (104) based on the acquired measured values.