Digital X-Ray Image Assembly Using Partial Dose Pre-Imaging
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Solution Overview
Problem
In digital x-ray imaging, existing exposure control methods result in low-dose pre-shots that are not diagnostically useful and incur additional unwanted radiation exposure due to detector and quantum noise, limiting the quality of the acquired image.
Innovation Solution
Determine a preliminary total dose using prior knowledge, acquire a complete pre-image with a partial dose (40-60% of the total), and then use the remaining dose to generate a final image, allowing for diagnostically usable images by combining the pre-image and following image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pre-shot with low dose is performed to control exposure parameters, then the acquisition parameters can be correctly set, but the pre-shot cannot be used for diagnostic purposes and represents additional unwanted radiation exposure
Solution Approach 1:
The total image acquisition is segmented into two separate acquisitions: a first image with partial dose for exposure control and a second image with remaining dose for diagnostic quality. This allows the exposure control function to be separated from the diagnostic imaging function, enabling the first image to serve dual purposes when combined with the second image.
Solution Approach 2:
The first image acquisition with partial dose is performed as a preliminary action to determine the correct exposure parameters before the main diagnostic acquisition. This preliminary exposure control allows optimization of the second image's exposure without requiring a separate discarded pre-shot.
2Reliability
If signals from all individual detectors are acquired separately to create a complete pre-image, then the pre-image can be diagnostically utilized, but the radiation exposure cannot be fully optimized
Solution Approach 1:
The first image is evaluated to provide feedback on the actual exposure conditions, allowing determination of the remaining dose required for the second image. This feedback mechanism ensures that the total radiation exposure is optimized while maintaining diagnostic quality in the combined image.
Solution Approach 2:
The acquisition parameters (particularly dose distribution) are changed between the two acquisitions. The first image uses partial dose for exposure control, while the second image uses the calculated remaining dose. This parameter adjustment allows optimal utilization of total radiation exposure while ensuring diagnostic quality.
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 method ensures optimal utilization of radiation exposure, minimizing noise and unnecessary dose, while enabling high-quality diagnostic images by utilizing the signals from all detectors for the pre-image and combining them with the following image.
Implementation Method 1
x-ray tube (2) for generation of x-rays (3)
Implementation Method 2
a large-surface digital x-ray detector (10) having a number of individual detectors (12) arranged in a matrix-like array
Data Source
AI summary
In a method and apparatus for generation of a digital x-ray image of an examination subject with an x-ray tube and a digital x-ray detector, a preliminary total dose required for correct exposure is determined using prior knowledge and a complete pre-image of the examination subject is acquired with a partial dose that is smaller than the preliminary total dose. A remaining dose is determined from the pre-image by image evaluation. A complete following image is acquired with this remaining dose, and the final x-ray image is assembled from the pre-image and the following image.