Dose Calculation Using Ray-Sum Image Shape Correction
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Solution Overview
Problem
Current dose calculation methods in X-ray CT imaging do not reliably account for the physical shape of a subject, leading to inconsistent dose calculations due to variations in body width and gantry position, and require complex processes to obtain accurate dose information from multiple tomographic images.
Innovation Solution
A dose calculation apparatus and system that utilize a ray-sum image to specify physical shape information, such as body width and thickness, to acquire correction coefficients and calculate dose based on X-ray intensity, enabling accurate dose calculation by reflecting the subject's physical shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If physical shape information is obtained from AP scanned images, then dose calculation considers body width, but the distance between subject and X-ray tube varies causing inconsistent body width measurements
Solution Approach 1:
The patent transitions from 2D AP scanned images to 3D ray-sum images generated from multiple tomographic images. This dimensional change allows obtaining physical shape information that is independent of gantry position and distance variations, resolving the inconsistency in body width measurements while maintaining dose calculation accuracy.
2Measurement precision
If multiple tomographic images are used to obtain physical shape information, then accurate dose calculation is achieved, but the process becomes complicated requiring specification of one image from multiple images
Solution Approach 1:
The patent combines multiple tomographic images into a single ray-sum image that integrates physical shape information from all images. This merging eliminates the need to select and specify individual images, simplifying the process while maintaining accurate dose calculation based on comprehensive physical shape data.
3Ease of operation
If CTDIvol is used as dose evaluation index, then dose management is simplified, but the physical shape of subject is not considered strictly
Solution Approach 1:
The patent applies local quality by obtaining specific physical shape information (body width and body thickness) from the ray-sum image and applying corresponding correction coefficients to the CTDIvol. This allows the dose calculation to be tailored to the individual subject's anatomy while maintaining the simplicity of CTDIvol-based management.
Data Source
AI summary
A dose calculation apparatus includes a specifying unit that specifies physical shape information of at least one of a body width and a body thickness of a subject using a ray-sum image generated from a plurality of medical images acquired by imaging the subject with an X-ray apparatus, an acquisition unit that acquires a correction coefficient corresponding to the physical shape information of at least one of the body width and the body thickness specified by the specifying unit from a storage unit configured to store a relationship between the physical shape information and the correction coefficient, and a calculation unit that calculates dose in accordance with a physical shape of the subject based on the correction coefficient acquired by the acquisition unit and a value representing X-ray intensity during taking of medical images.