Autoexposure Control Using Predicted Time Point Estimation
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Solution Overview
Problem
Existing radiographic imaging systems face challenges in accurately estimating the predicted time point for reaching a target cumulative dose of X-rays due to time lags in X-ray emission, leading to potential over-exposure and inefficiencies in imaging, especially for low-dose and short-irradiation procedures.
Innovation Solution
A radiographic imaging apparatus with a detection panel and dose sampler that monitors radiation and detects the start of irradiation, allowing for precise autoexposure control by sampling the dose signal from the start time and estimating the predicted time point for stopping irradiation based on the cumulative dose, using a correlation between cumulative dose and elapsed time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the cumulative dose is monitored from the reception time of the sync signal, then the autoexposure control can be performed, but the time lag causes inaccurate estimation of the predicted time point for reaching target cumulative dose
Solution Approach 1:
The patent applies preliminary action by detecting the start of irradiation before the sync signal reception time and using this detected start time as the reference point for cumulative dose monitoring. This allows the system to compensate for the time lag by establishing the actual irradiation start moment, thereby accurately estimating the predicted time point when the cumulative dose reaches the target value.
2Object-affected harmful factors
If the irradiation is stopped based on cumulative dose reaching target value, then the radiation exposure to body can be minimized, but the time lag may cause over-exposure in low-dose and short-irradiation procedures
Solution Approach 1:
The patent implements feedback by continuously monitoring the cumulative dose during irradiation and comparing it with the target cumulative dose value. When the monitored cumulative dose reaches the target value, the system provides feedback to stop the irradiation. This closed-loop control ensures accurate exposure control and prevents over-exposure, especially in low-dose and short-irradiation procedures.
Solution Approach 2:
The system performs preliminary detection of the irradiation start time and uses this information to adjust the cumulative dose monitoring timeline, ensuring that the target cumulative dose is reached at the correct moment rather than being offset by system delays.
3Ease of operation
If the sync signal is used to synchronize the start of irradiation with the start of storing, then the imaging process can be coordinated, but the time lag reduces the efficiency of imaging procedures
Solution Approach 1:
The patent applies preliminary action by detecting the actual start of irradiation before the sync signal is received and using this detected start time to initiate cumulative dose monitoring. This eliminates the delay caused by waiting for the sync signal and allows the system to efficiently track the cumulative dose from the true irradiation start moment, improving imaging procedure efficiency.
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 enables precise autoexposure control, reducing the risk of over-exposure and improving the efficiency of imaging procedures by accurately predicting the time to reach the target cumulative dose, even in low-dose and short-irradiation scenarios.
Implementation Method 1
The detection panel, for example, flat panel detector (FPD), detects an X-ray image as electric signal
Data Source
AI summary
In an X-ray imaging apparatus, a detection panel has monitor pixels for monitoring X-rays. A signal processor samples a dose signal of a dose per unit time of X-rays according to an output of the monitor pixels. A start detector checks whether irradiation of X-rays is started according to a result of comparison between the dose signal and a start threshold. An AEC device acquires cumulative dose from a start time of the start of irradiation of X-rays until acquisition time after a predetermined time according to the dose signal. According to the cumulative dose, a predicted time point of a reach of the cumulative dose to a target dose is estimated. A stop signal is transmitted to a radiation source controller at the predicted time point, to stop the irradiation of X-rays.