Which device may be used in place of the photomultiplier tube (PMT) within a CR image reader system?

Which device may be used in place of the photomultiplier tube (PMT) within a CR image reader system?

• A. TFT
• B. A-Se
• C. CCD
• D. ADC

Answer: (C)

In a CR image reader, the light emitted from the photostimulable phosphor during readout must be detected and converted into an electronic signal. While a photomultiplier tube has traditionally done this, a CCD can serve the same role. A CCD is a solid-state light detector organized into a pixel array; it collects photons from the scanned light and converts them into charge that forms the digital image with good spatial resolution. It integrates smoothly with the line-by-line readout of CR systems and avoids the high-voltage requirements of a PMT. The other options aren’t suitable here: a TFT is used mainly in flat-panel DR detectors, amorphous selenium is a photoconductor for direct DR, and an ADC is merely a digitizer that comes after detection, not the detector itself. So, a CCD is the appropriate substitute for a PMT in a CR reader.

In a CR image reader, the light emitted from the photostimulable phosphor during readout must be detected and converted into an electronic signal. While a photomultiplier tube has traditionally done this, a CCD can serve the same role. A CCD is a solid-state light detector organized into a pixel array; it collects photons from the scanned light and converts them into charge that forms the digital image with good spatial resolution. It integrates smoothly with the line-by-line readout of CR systems and avoids the high-voltage requirements of a PMT. The other options aren’t suitable here: a TFT is used mainly in flat-panel DR detectors, amorphous selenium is a photoconductor for direct DR, and an ADC is merely a digitizer that comes after detection, not the detector itself. So, a CCD is the appropriate substitute for a PMT in a CR reader.