CT X-ray Dose Modulation Using Attenuation Data
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Solution Overview
Problem
Current CT scan technologies face challenges in accurately modulating x-ray radiation dose, leading to potential excessive irradiation and image quality issues due to individual subject differences and inaccurate approximation of scan slices as ellipses.
Innovation Solution
The method involves acquiring x-ray attenuation information from finished scanning sequences to modulate the radiation dose for each projection angle at different Z positions, using equations to calculate and adjust the dose based on maximum attenuation values and shape ratios, ensuring consistent noise between CT image reconstructions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If x-ray radiation dose is increased to improve image quality, then image quality is improved, but radiation absorbed by the subject increases causing potential harm
Solution Approach 1:
The patent applies local quality by modulating the x-ray radiation dose according to the specific attenuation characteristics of different scan slices. Instead of using a uniform dose throughout the entire scan volume, the system calculates and applies different dose levels to different Z positions based on the subject's anatomical structure and x-ray attenuation properties, thereby optimizing image quality in each region while minimizing overall radiation exposure
Solution Approach 2:
The patent changes the radiation dose parameter dynamically based on calculated attenuation information. The system determines the appropriate dose level for each projection angle and Z position by considering the subject's anatomical characteristics and the specific imaging requirements, allowing the dose parameter to vary continuously throughout the scan rather than remaining fixed
2Device complexity
If scan slices are approximated as ellipses to simplify processing, then processing complexity is reduced, but accuracy of dose modulation decreases due to individual subject differences
Solution Approach 1:
The patent performs preliminary actions by acquiring reference data from a standard subject before actually scanning the patient. The system pre-calculates attenuation information and dose modulation parameters based on the reference standard, then applies these pre-computed values to the actual patient scan. This preliminary preparation simplifies the real-time processing while maintaining high accuracy through the use of standardized anatomical models
Solution Approach 2:
The patent uses copying by creating a virtual model of the subject's anatomy based on reference data. Instead of directly measuring and processing complex individual anatomical variations in real-time, the system copies the attenuation characteristics from standardized reference subjects and applies them to the actual scan, thereby simplifying processing while preserving accuracy through the use of representative anatomical models
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 effectively reduces radiation absorbed by the subject while maintaining image quality by optimizing x-ray radiation dose modulation, ensuring accurate and consistent CT image reconstructions across different scan regions.
Implementation Method 1
acquire, from data of a finished scanning sequence, a maximum x-ray attenuation value for each of different projection angles of an XY scanning profile at each of different Z positions within a planned scanning sequence
Data Source
AI summary
A method for modulating x-ray radiation dose in CT scan is disclosed. The method may include: acquiring x-ray attenuation information of each Z position within a planned scanning sequence for a scan region of a subject from data of a finished scanning sequence for the subject; and then, based on the acquired x-ray attenuation information, performing dose modulation with respect to the XY scanning profile at each Z position within the planned scanning sequence. The finished scanning sequence can be an axial and/or helical scanning sequence for a scan region wholly or partially same as the scan region and has been performed earlier. The Z position may include a position in Z direction extending from head to foot of the subject or conversely. The XY scanning profile may include a scanning profile of the subject which is vertical to Z direction.