Digital X-Ray Image Acquisition Parameter Control
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Solution Overview
Problem
In digital x-ray image acquisition, the use of automatic exposure control with solid-state detectors results in unnecessary radiation exposure due to averaging of measurement fields, which cannot be diagnostically utilized and requires additional pre-shot exposure to determine acquisition parameters.
Innovation Solution
The method involves acquiring individual x-ray images in temporal succession that overlap in diagnostically-relevant regions, forming intermediate images to control acquisition parameters such as exposure time, and optimizing these parameters based on spatial resolution and examination subject composition, eliminating the need for a pre-shot exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pre-shot with reduced radiation dose is used to determine acquisition parameters, then the exposure parameters can be optimized, but additional radiation exposure is incurred that cannot be diagnostically utilized
Solution Approach 1:
The patent applies preliminary action by performing a pre-shot acquisition with reduced radiation dose before the main diagnostic acquisition. This pre-shot captures preliminary image data that is used to determine optimal acquisition parameters (exposure time, tube current, voltage) for the subsequent diagnostic image, ensuring parameter optimization while minimizing total radiation exposure through strategic timing of the preliminary measurement.
Solution Approach 2:
The patent uses the pre-shot acquisition to create a copy or approximation of the diagnostic image at reduced quality and dose. This preliminary copy contains sufficient information to determine acquisition parameters without needing to be diagnostically usable itself, thereby separating the parameter determination function from the diagnostic imaging function and reducing unnecessary radiation exposure.
2Extent of automation
If measurement data from pre-shot is averaged into measurement fields, then acquisition parameters can be determined, but the measurement data cannot be diagnostically utilized
Solution Approach 1:
The patent segments the image acquisition process into distinct functional stages: a pre-shot stage for parameter determination and a main acquisition stage for diagnostic imaging. The measurement data from the pre-shot is processed separately to extract acquisition parameters, while the main acquisition generates the diagnostically usable image. This segmentation allows automatic exposure control to function independently without compromising diagnostic information quality.
Solution Approach 2:
The patent makes the pre-shot acquisition serve multiple functions: it provides data for automatic exposure control parameter determination and simultaneously creates a preliminary image record. By designing the pre-shot to fulfill both parameter measurement and preliminary imaging roles, the system reduces information loss and allows flexibility in whether the pre-shot data can be partially utilized diagnostically.
3Ease of operation
If individual detectors are combined into measurement fields for pre-shot, then acquisition parameters can be controlled, but spatial resolution is reduced
Solution Approach 1:
The patent applies local quality by using different detector configurations for different purposes: individual detectors or small groups maintain high spatial resolution for diagnostic imaging, while larger groups are combined into measurement fields specifically for the pre-shot parameter determination. This local differentiation allows automatic exposure control to function with reduced resolution requirements while preserving high resolution for the actual diagnostic images.
Solution Approach 2:
The patent uses partial action by combining detectors into measurement fields only for the pre-shot acquisition, not for the main diagnostic acquisition. This partial combining is sufficient to determine acquisition parameters with adequate precision while avoiding the resolution loss that would occur if all detectors were always combined. The excessive combination is avoided by maintaining individual detector capability for high-resolution imaging.
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 allows for diagnostically-usable digital x-ray images to be generated with optimized acquisition parameters, reducing radiation exposure and enabling real-time control of image acquisition, including detection of subject displacement and positioning errors.
Implementation Method 1
an x-ray tube 2 for generation of x-rays that traverse an examination subject 4
Implementation Method 2
a digital x-ray detector 10 that is formed by a number of individual detectors 12 arranged in a matrix-like array; the measurement signals of the individual detectors 12 are combined into a digital individual image Bi
Data Source
AI summary
In a method and an apparatus for acquisition of a digital x-ray image of an examination subject with a digital x-ray receiver, the digital x-ray image being composed of a number of individual images acquired in temporal succession and overlapping one another at least in one diagnostically-relevant subject region, at least one intermediate image composed of a number of individual images is evaluated to control at least one acquisition parameter used to generate the x-ray image. For the acquisition of digital x-ray images, an exposure control without exposure of the patient to an additional radiation dose is possible.