Radiography Sensor Triggering via Charge Detection
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Solution Overview
Problem
In filmless dental radiography, existing systems face challenges in minimizing patient exposure to x-rays and achieving accurate image acquisition due to the lack of communication between the x-ray source and the sensor, leading to increased radiation dose and inefficiencies in detecting x-ray pulses.
Innovation Solution
A filmless dental radiography system with a sensor coupled to control circuitry via a link, which automatically detects electromagnetic radiation and triggers image acquisition, using a scintillator to convert x-rays into a detectable signal and control circuitry to monitor and respond to radiation presence, enabling precise timing for image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a partial frame acquisition method is used to detect x-ray presence, then the system can determine when to begin full image acquisition, but a significant portion of the x-ray pulse (10-20%) is consumed for detection, increasing patient radiation exposure
Solution Approach 1:
The sensor array is divided into multiple independent sensor elements that can be selectively activated. During the detection phase, only a subset of sensor elements is used to detect x-ray presence, while during the full image acquisition phase, all sensor elements are activated. This segmentation allows efficient use of the x-ray pulse by dedicating specific sensors to detection and others to imaging.
Solution Approach 2:
The system performs preliminary detection of x-ray presence using a minimal subset of sensor elements before initiating full image acquisition. This preliminary action allows the system to prepare for optimal image capture timing without consuming significant radiation dose, as the detection phase uses only a fraction of the available sensors.
2Reliability
If diodes are added to corners of the intraoral sensor to detect x-ray presence, then detection capability is improved, but the diodes do not cover the entire field of view, resulting in missed x-ray pulses and increased radiation dosage
Solution Approach 1:
The sensor array serves dual functions: individual sensor elements can act as detection elements during the detection phase and as imaging elements during the acquisition phase. This multi-functionality eliminates the need for separate detection components like corner diodes, ensuring complete field of view coverage while maintaining detection capability.
Solution Approach 2:
The sensor array itself performs both detection and imaging functions without requiring additional dedicated detection components. The system uses its own sensor elements to detect x-ray presence and then captures the full image, making the sensor array self-sufficient for both tasks.
3Adaptability or versatility
If the x-ray source and sensor are sold as separate components with no communicative link, then system flexibility is maintained, but the system cannot tell when to begin image acquisition
Solution Approach 1:
A control circuit acts as an intermediary between the x-ray source and the sensor array. The control circuit receives signals from the x-ray source indicating when an x-ray pulse is being emitted and automatically triggers the activation of the sensor array at the optimal time. This intermediary enables automatic coordination between separate components while maintaining their independence.
Solution Approach 2:
The system implements a feedback mechanism where the control circuit monitors the x-ray source operation and uses this information to automatically control the timing of sensor activation. The control circuit receives feedback about x-ray pulse emission and adjusts sensor activation accordingly, enabling automatic image acquisition triggering without requiring integrated components.
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 solution reduces patient radiation exposure by optimizing the detection of x-ray pulses and improving image acquisition efficiency, allowing for shorter exposure times and more accurate imaging without increasing the radiation dose.
Implementation Method 1
use a scintillator to convert x-rays into a detectable signal
Implementation Method 2
an electronic sensor is placed in the patient's mouth behind the tooth to be examined... The x-rays pass through the tooth and impinge on the electronic sensor, which converts the x-rays into an electrical signal
Data Source
AI summary
An apparatus for triggering image acquisition in radiography includes an interconnect, a detector to detect radiation and a switch coupled between the interconnect and the detector to charge the interconnect in response to the radiation while the switch is in an open-circuit state. The apparatus also includes control circuitry coupled to the interconnect to detect the charge on the interconnect and to generate a signal indicating presence of the radiation in response to the charge. A method for triggering image acquisition in radiography includes coupling a switch between an interconnect and a detector, then charging an interconnect with that switch in response to radiation incident upon the switch while the switch is in an open-circuit state. Next, the charge on the interconnect is monitored and a signal is generated indicating the presence of the radiation in response to that charge.