X-Ray Detector Dual Readout for Saturation Signal Correction
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Solution Overview
Problem
X-ray diagnostic apparatuses face saturation issues due to excessive X-ray doses, leading to incorrect signal reading and artifacts in generated images, with existing saturation correction methods being inaccurate in estimating incident doses.
Innovation Solution
The apparatus employs a dual readout method, including non-destructive reading before exposure termination and destructive reading after exposure, to estimate saturation regions and correct signals using aligned image levels from both readouts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the X-ray detector receives direct rays, then the dose of X-rays incident upon the X-ray detector will exceed a maximum incident dose, causing saturation and incorrect signal reading, but increasing the X-ray dose improves image quality and diagnostic accuracy
Solution Approach 1:
The patent performs a non-destructive readout of the X-ray detector signal before the exposure period ends, allowing the system to detect saturation conditions in advance. This preliminary reading enables the system to identify when the detector is approaching its maximum capacity and take corrective action before complete saturation occurs, thereby preserving measurement accuracy while maintaining the benefit of higher X-ray doses for improved image quality.
Solution Approach 2:
The patent implements a feedback mechanism where the non-destructive readout signal is continuously monitored during the X-ray exposure period. The system compares the readout signal against predetermined threshold values to detect saturation conditions in real-time. When saturation is detected, the system can adjust the X-ray dose or other parameters to prevent complete saturation, ensuring accurate signal reading while maintaining optimal image quality.
2Reliability
If saturation correction is performed by estimating the incident dose in the saturation region, then saturation correction can be applied, but the estimation is difficult and inaccurate
Solution Approach 1:
The patent introduces an intermediary approach by using the non-destructive readout signal as a mediator between the X-ray exposure and the final image processing. This intermediary reading provides an accurate measurement of the incident dose in the saturation region without requiring complex estimation algorithms. The non-destructive readout acts as a bridge, allowing the system to directly measure the saturation condition and use this information for accurate correction, thereby eliminating the difficulty and inaccuracy associated with traditional estimation methods.
3Ease of operation
If a single destructive readout is performed after X-ray exposure, then the signal can be read, but the signal cannot be read before exposure termination, preventing early saturation detection
Solution Approach 1:
The patent segments the signal reading process into two distinct parts: a non-destructive readout performed during the X-ray exposure period and a destructive readout performed after exposure termination. This segmentation allows the system to perform early saturation detection during the exposure period while also maintaining the ability to read the final signal after exposure. The non-destructive readout can be performed multiple times at different timings during exposure, providing flexible and reliable saturation detection without compromising the final signal reading capability.
Data Source
AI summary
According to one embodiment, an X-ray diagnostic apparatus including processing circuitry. The processing circuitry is configured to cause an X-ray detector to read a signal in a non-destructive readout before termination of X-ray exposure, the signal being accumulated in an X-ray detection element; cause the X-ray detector to read the signal in a destructive readout after termination of X-ray exposure; acquire first projection data generated based on the signal read in the non-destructive readout and acquire second projection data generated based on the signal read in the destructive readout; estimate, based on the second projection data, a saturation region in which saturation is occurring; and replace a signal in the saturation region of the second projection data with a signal in the saturation region of the first projection data.