Automatic Tube Current Modulation via Surface Contour Characterization
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Solution Overview
Problem
Existing CT imaging systems fail to accurately adjust radiation exposure based on patient anatomy, leading to increased dose due to assumptions of uniform shape and density, and require additional scout images that defeat the purpose of automatic tube current modulation.
Innovation Solution
An automatic tube current modulation method that uses surface contour characterization to determine optimized tube current modulation, accounting for actual patient shape and density without the need for scout images, by acquiring reflectance images, forming a virtual anatomy model, and computing modulation factors at each modulation point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing ATCM systems use orthogonal scout images to compute tube current modulation, then tube current can be adjusted according to body part characteristics, but patient radiation dose increases due to requiring additional scout images
Solution Approach 1:
The patent extracts only the essential surface contour information needed for tube current modulation, eliminating the requirement for full orthogonal scout images. By using a simplified surface mapping approach that captures only the necessary anatomical dimensions, the system achieves modulation accuracy without the additional radiation burden of complete scout imaging.
Solution Approach 2:
The system performs preliminary surface contour characterization using non-radiographic methods (such as optical surface scanning or simplified projection) before the actual CT acquisition. This preliminary action provides the necessary anatomical information for tube current calculation without exposing the patient to additional radiation during the scanning preparation phase.
2Device complexity
If existing ATCM systems assume uniform symmetric shape and contour, then device complexity is reduced, but manufacturing precision and adaptability to actual patient anatomy deteriorate
Solution Approach 1:
The patent applies local quality by characterizing the patient's surface contour with position-specific parameters rather than assuming uniform symmetry. The system divides the body surface into multiple measurement points or regions, each with its own contour characteristics, allowing accurate representation of asymmetric and variable patient anatomy while maintaining computational efficiency.
Solution Approach 2:
The system changes from fixed geometric assumptions to variable parameter representation of patient anatomy. By using measured surface contour parameters (such as radial distances, curvature values, or thickness measurements) that can vary at different angular positions and z-locations, the system accurately captures actual patient shape without requiring complex full 3D modeling.
Data Source
AI summary
A method for generating a modulation tube current waveform acquires reflectance images of a subject and generates a surface contour characterization of the subject according to the reflectance images. The surface contour is registered to the imaged field of view. A volume image is formed according to the generated surface contour. A modulation factor for the radiographic volume imaging apparatus is determined at a plurality of modulation points. A modulation tube current waveform is generated using the modulation factor.