Tech Primer
Digital x-ray imaging is leading a revolution in diagnostic radiology. In conventional x-ray systems, only less than 40% of the original image information is available to produce an image owing to the signal attenuation in each component. By adding a digital photo detector array to digital x-ray imaging, it’s possible to capture more than 80% of the original image information to further improve the image quality. Using digital x-ray imaging can also decrease patients’ exposure to radiation, reduce diagnosis time, and save cost as well.
The digital x-ray imaging can be achieved in two ways, direct and indirect conversion. Direct conversion imaging utilizes flat-panel selenium to absorb x-rays directly and convert them into electric charges. In indirect conversion process, x-ray signals are converted into light first, and then converted into electric charges by using photodiode, CCD or CMOS imaging sensors. These small signals (electric charges) are amplified and converted into digital signals by AFE, and then sent to signal processing module for the final display. FPGA, DSP can be used to implement these functions. These image data can be transmitted to computers by USB/UART or wireless for further analysis.
At present, the well-known semiconductor companies around the world such as ADI, TI can provide the solutions for digital x-ray. Other semiconductor manufacturers like Altera, Freescale, Maxim and ST also can provide some relevant devices.
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