CT Scanner Angular Intensity Modulation for X-Ray Dose Reduction
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Solution Overview
Problem
Current X-ray imaging technologies face challenges in minimizing the X-ray dose while maintaining high image quality, as existing methods for dose reduction often compromise on noise levels and image fidelity.
Innovation Solution
An X-ray imaging apparatus and method that modulate X-ray emissions to occur only at specific 'emission angle intervals' with controlled angular distribution, allowing for a desired angular intensity distribution to be approximately reproduced, thereby minimizing dose exposure while maintaining high local emission intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous X-ray emissions are used to maintain high image quality, then image fidelity is improved, but X-ray dose exposure increases
Solution Approach 1:
The patent applies periodic action by modulating the X-ray tube current in a periodic manner according to a predetermined modulation curve, switching between different current levels (including zero current) at different angular positions. This periodic modulation allows the system to emit X-rays only when necessary (at specific angular intervals) while maintaining the desired angular intensity distribution on average, thereby reducing overall dose exposure while preserving image quality.
Solution Approach 2:
The patent implements dynamics by making the X-ray tube current variable and adaptive rather than constant. The controller dynamically adjusts the tube current based on the modulation curve and detected object characteristics, allowing the system to optimize the balance between image quality and dose reduction in real-time during the scanning process.
2Object-affected harmful factors
If X-ray tube current is modulated to reduce dose, then X-ray dose exposure is reduced, but image noise increases
Solution Approach 1:
The patent applies parameter changes by modifying the tube current parameter dynamically during scanning according to a predetermined modulation curve. By changing the current parameter in a controlled periodic manner rather than maintaining a constant low current, the system achieves dose reduction while preventing excessive noise through strategic high-current emission intervals.
3Object-affected harmful factors
If X-ray emissions are concentrated at specific angle intervals, then dose exposure is reduced, but angular intensity distribution uniformity worsens
Solution Approach 1:
The patent applies local quality by allowing different angular intervals to have different emission characteristics. The modulation curve is designed to provide different current levels at different angular positions, creating a non-uniform local emission pattern that, when averaged over the complete scan, reproduces the desired uniform angular intensity distribution while maintaining localized dose reduction.
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 X-ray dose exposure while preserving image quality by bundling emissions into intervals, enabling iterative reconstruction methods to maintain image fidelity even with reduced flux, thus minimizing noise and signal degradation.
Implementation Method 1
an X-ray source for emitting X-rays towards the object from different viewing angles
Data Source
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AI summary
The invention relates to an X-ray imaging apparatus and a method, particularly to a CT scanner (100) for generating sectional images of an object such as the body (P) of a patient. A given desired angular intensity distribution (Ides) is reproduced by emitting X-rays (X) in emission angle intervals (EAI) only, wherein the angular distribution of these emission angle intervals and the associated local emission intensities (1(α)) are chosen such that they reproduce, in the angular mean, the desired angular intensity distribution (Ides). Modulation of incident X-ray flux is hence realized by the modulation of the angular sampling density. The X-ray source may preferably be realized by a grid switching tube (101).