CT Dose Modulation Around Sensitive Organs Under Speed Limits
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Solution Overview
Problem
Existing X-ray CT apparatuses struggle to maintain image quality while effectively reducing the emission dose to sites with high radiation sensitivity, such as the eye or mammary gland, due to insufficient control over the emission dose and hardware limitations.
Innovation Solution
An X-ray CT apparatus with a controller that modulates the emission dose using a modulation pattern setting section and adjustment section, adjusting the emission dose based on an upper limit speed to ensure reduced exposure to sensitive areas while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the emission dose is increased to improve image quality, then the image quality of the tomographic image is improved, but the exposure dose to the subject increases
Solution Approach 1:
The patent applies local quality by differentiating the emission dose across different spatial locations. Specifically, the modulation pattern setting section reduces the emission dose to sites with high radiation sensitivity (such as eyes and mammary glands) while maintaining or increasing the emission dose to other sites. This spatial differentiation allows the system to protect sensitive areas without compromising overall image quality, as the non-sensitive areas receive sufficient radiation for proper imaging.
2Object-affected harmful factors
If the modulation speed of the emission dose is increased to reduce exposure to sensitive sites, then the emission dose to sensitive sites is reduced, but the image quality deteriorates due to shortage of emission dose
Solution Approach 1:
The patent implements dynamics by making the emission dose modifiable and adjustable in real-time during the imaging process. The modulation pattern setting section dynamically adjusts the emission dose based on the rotational position of the X-ray source, creating a time-varying dose distribution. This dynamic modulation allows the system to reduce exposure to sensitive sites when they are in the imaging path while maintaining sufficient dose for image quality in other positions.
3Measurement precision
If the modulation pattern is adjusted based on upper limit speed, then the emission dose control precision is improved, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing modulation patterns that account for the upper limit speed of the emission dose modulation. The modulation pattern setting section contains pre-established patterns that are designed to work within the hardware constraints, eliminating the need for complex real-time calculations during imaging. This preliminary preparation allows for precise emission dose control while keeping the actual imaging process relatively simple.
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
The apparatus achieves reduced exposure dose to high radiation sensitivity sites while preserving image quality by dynamically adjusting the emission dose according to hardware limitations, ensuring balanced image quality and exposure.
Implementation Method 1
an X-ray source that emits an X-ray to a subject, an X-ray detector that detects the X-ray transmitted through the subject
Data Source
AI summary
An X-ray CT apparatus includes a rotating plate that causes an X-ray source and an X-ray detector to rotate around a subject, an image generation section that generates a tomographic image of the subject based on a detection signal. A controller controls each unit and has a modulation pattern setting section that sets a modulation pattern used for modulation of an emission dose, which is an X-ray dose emitted from the X-ray source while the rotating plate rotates, such that the emission dose to a site having high radiation sensitivity of the subject is reduced more than the emission dose to other sites, and a modulation pattern adjustment section that adjusts the modulation pattern based on an upper limit speed, which is an upper limit of a modulation speed of the emission dose.