Focused Tomography Adaptive Collimator Radiation Dosage Control
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Solution Overview
Problem
The increasing prevalence of computerized tomography (CT) scans has led to a significant increase in cumulative radiation dosage for patients, posing a risk of cancer due to long-term exposure, as existing technologies often expose entire body slices to full radiation doses, even when only a limited region of interest is needed.
Innovation Solution
The development of focused tomography systems and methods that allow for variable sampling of x-rays, concentrating radiation on the region of interest (ROI) and using dramatically reduced radiation doses outside the ROI, enabling accurate image reconstruction with significantly lower overall radiation exposure, achieved through the use of low and high frequency kernel decomposition and adaptive sampling schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full radiation dose is applied to entire body slices during CT scanning, then complete image data is obtained for all regions, but radiation exposure to radiosensitive organs increases significantly
Solution Approach 1:
The patent applies local quality by differentiating radiation dosage across different spatial regions. High radiation dose is concentrated on the region of interest (ROI) where diagnostic information is needed, while low or zero radiation dose is applied to surrounding areas containing radiosensitive organs. This is achieved through adaptive sampling schemes that weight projections based on their contribution to ROI reconstruction, and kernel decomposition methods that separate local and non-local frequency components.
Solution Approach 2:
The patent segments the frequency spectrum into low and high frequency components using kernel decomposition. High frequency components (which contain fine detail information) are reconstructed primarily from local projections through the ROI, while low frequency components (which contain overall structure information) are reconstructed from non-local projections. This segmentation allows selective application of radiation based on the spatial and frequency characteristics of different image components.
2Object-affected harmful factors
If radiation dose is reduced outside the region of interest, then exposure to radiosensitive organs is minimized, but image reconstruction accuracy may deteriorate
Solution Approach 1:
The patent changes the parameter of radiation dosage from a uniform value to a spatially varying value. The radiation dose parameter is adjusted based on the projection angle and position relative to the ROI. Projections that pass through the ROI are assigned high dose weights, while projections that only pass through non-ROI areas are assigned low or zero dose weights. This parameter change enables selective radiation application while maintaining reconstruction accuracy through mathematical compensation.
Solution Approach 2:
The patent introduces mathematical intermediaries in the form of adaptive sampling weights and kernel functions. These intermediaries mediate between the limited low-dose projections from non-ROI areas and the final high-quality image reconstruction. The adaptive sampling scheme acts as an intermediary that selectively emphasizes projections contributing to ROI quality, while the kernel decomposition serves as a mathematical intermediary that separates and processes different frequency components with appropriate weighting.
3Loss of energy
If variable sampling of x-rays is implemented with adaptive weighting, then radiation dosage is optimized for the region of interest, but system complexity increases
Solution Approach 1:
The patent replaces mechanical complexity with mathematical complexity. Instead of requiring complex mechanical systems to physically adjust radiation dosage for each projection angle, the system uses a single rotating x-ray source that emits uniform radiation, combined with mathematical post-processing through adaptive sampling weights and kernel decomposition. The physical system remains simple (standard CT hardware), while the computational algorithms handle the complexity of selective radiation optimization.
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 reduces radiation dosage by up to 80% while maintaining image quality, making it particularly beneficial for sensitive areas like children and pregnant women, and allowing for precise imaging of cylindrical and non-cylindrical anatomy with minimal exposure to radiosensitive organs.
Implementation Method 1
an x-ray transmitter and an x-ray detector are positioned opposite of each other
Data Source
AI summary
An exemplary focused tomography system comprises an x-ray transmitter that is configured to emit a radiation beam and an x-ray detector that is configured to detect incident radiation from the radiation beam. The system further includes an adaptive collimator device arranged between the x-ray transmitter and the x-ray detector and a controller device connected to the x-ray transmitter that is configured to cause the x-ray transmitter to emit the radiation beam at a first radiation dosage level when a path of the radiation beam intersects a region of interest of the subject and cause the x-ray transmitter to emit the radiation beam at a second radiation dosage level when the path of the radiation beam does not intersect the region of interest of the subject, such that the second radiation dosage level is less than the first radiation dosage level. Data within the region of interest can be reconstructed with image quality equivalent to traditional computed tomography scans.