Dynamic Collimation for CT Scanners
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Solution Overview
Problem
Computed tomography (CT) scanners emit excessive ionizing radiation, damaging cells and increasing cancer risk due to irradiating larger areas than necessary during scans of a region of interest (ROI), as existing collimation methods do not dynamically adjust to the geometry of the ROI.
Innovation Solution
A dynamic collimation system that adjusts the geometry and location of the radiation beam in real-time to match the geometry and location of the ROI, using a collimator controller and detector array to track the ROI's movement, reducing unnecessary radiation exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a fixed collimation is used during CT scanning, then the radiation beam covers a predetermined area, but the patient receives excessive radiation dose by irradiating areas outside the region of interest
Solution Approach 1:
The collimator is made dynamically adjustable during the scanning process. The collimation geometry changes in real-time to match the region of interest, allowing the radiation beam to be confined only to the necessary area while maintaining scanning functionality. This dynamic adaptation resolves the contradiction between fixed collimation and adaptive radiation dose reduction.
Solution Approach 2:
The collimation parameters (aperture size, shape, and position) are continuously changed during scanning based on the region of interest geometry. By adjusting these parameters dynamically, the system achieves both reduced radiation dose and adaptability to different scanning requirements.
2Object-affected harmful factors
If the radiation beam is confined only to the region of interest, then patient radiation dose is reduced, but the collimation system becomes more complex
Solution Approach 1:
The collimator is designed to perform multiple functions: it serves as both a fixed collimation device for standard scans and a dynamically adjustable device for ROI-specific scans. This multi-functionality reduces the need for separate systems while achieving dose reduction through adaptive collimation.
3Object-affected harmful factors
If dynamic collimation is implemented to match ROI geometry, then unnecessary radiation exposure is minimized, but the control system complexity increases
Solution Approach 1:
The collimator controller uses feedback from the scanning system and ROI definition to automatically adjust collimation parameters. This closed-loop control enables the system to adapt to different ROI geometries without requiring complex manual intervention, balancing the trade-off between dose reduction and control 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
This approach significantly reduces the patient dose by ensuring the radiation beam only traverses the region of interest, minimizing exposure to areas outside the ROI, thereby lowering the risk of radiation-induced damage and cancer.
Implementation Method 1
The x-ray tube is configured to emit ionizing radiation at least in a direction towards the examination region
Implementation Method 2
A detector array, located across the examination region and opposite the x-ray tube, detects radiation traversing the examination region and the object or subject
Implementation Method 3
A source collimator collimates the radiation, producing a radiation beam, having a predetermined shape, which traverses the examination region
Data Source
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AI summary
A method includes performing a three dimensional volume scan of a region of interest located in a portion of an object or subject in an examination region, including dynamically collimating a radiation beam used to perform the scan so that a geometry and/or location of the radiation beam tracks, during the scan, to a geometry and/or location of the region of interest, wherein the region of interest is a sub-region of the portion of the object or subject in the examination region.