Beam-Shaping Filter for Cardiac CT Dose Reduction
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Solution Overview
Problem
Conventional CT imaging techniques irradiate the entire patient to avoid limited field-of-view artifacts, leading to increased radiation dose despite focusing on specific regions of interest, such as the heart, and fail to realize potential dose efficiencies from task-specific tailoring.
Innovation Solution
A method and apparatus that position the region of interest proximate to the isocenter of a CT scanner and use a static beam-shaping filter to attenuate X-ray radiation outside the region of interest, while maintaining a nonzero fluence level, allowing for conventional reconstruction and reducing radiation dose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the entire patient is irradiated to avoid limited field-of-view artifacts, then image quality is preserved, but radiation dose increases
Solution Approach 1:
The patent applies local quality by positioning the region of interest (heart) at the isocenter and using a beam-shaping filter to deliver tailored X-ray fluence distributions. The filter transmits X-rays with highest fluence to the region of interest while attenuating X-rays to peripheral areas, creating spatially varying fluence that matches the clinical need to image only the heart region with high quality while reducing overall dose.
Solution Approach 2:
The patent segments the imaging task by focusing exclusively on the region of interest (heart) rather than imaging the entire patient body. By positioning the heart at the isocenter and using a reduced scan diameter, the system separates the imaging of the heart from the irradiation of the entire patient, enabling dose reduction while maintaining image quality for the clinically relevant region.
2Object-affected harmful factors
If a beam-shaping filter is used to attenuate X-ray radiation outside the region of interest, then radiation dose is reduced, but image quality may degrade
Solution Approach 1:
The patent changes the fluence parameter spatially by using a beam-shaping filter with specific attenuation characteristics. The filter is designed to transmit X-rays with highest fluence to the region of interest (heart) while attenuating X-rays to peripheral areas. This parameter change in fluence distribution enables dose reduction to peripheral tissues while maintaining sufficient fluence to the heart for high-quality imaging.
Solution Approach 2:
The beam-shaping filter acts as an intermediary element between the X-ray source and the patient. It mediates the X-ray fluence distribution by selectively attenuating radiation in specific spatial regions, allowing the system to reduce dose to peripheral tissues while preserving image quality in the region of interest through its positioned at the isocenter.
3Object-affected harmful factors
If the scan field-of-view is reduced to focus on the region of interest, then radiation dose is reduced, but limited field-of-view artifacts may occur
Solution Approach 1:
The patent resolves this contradiction by positioning the region of interest (heart) at the isocenter, where the X-ray beam has highest fluence. This positioning allows the use of a reduced scan diameter that focuses radiation on the heart while maintaining sufficient fluence for high-quality imaging. The beam-shaping filter further enhances this by ensuring highest fluence is delivered to the heart region, enabling dose reduction without compromising image quality or introducing artifacts.
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 radiation dose while preserving image quality by tailoring X-ray fluence and tube current modulation to the specific region of interest, achieving substantial dose reductions with minimal image quality degradation.
Implementation Method 1
the beam-shaping filter is configured to attenuate the X-ray radiation on areas of the imaging target located outside of the region of interest
Data Source
AI summary
Methods, devices, and systems for computed tomography (CT) imaging technologies that are tailored to specific regions of interest and provide a reduced radiation dose. An imaging system for cardiac CT comprises a beam-shaping filtration and exposure control technologies specifically tailored to imaging of the heart.