Within a flat-panel detector, which device acts as the switch to release the collected charge?

Within a flat-panel detector, which device acts as the switch to release the collected charge?

• A. Scintillation Layer
• B. Photodiode
• C. CCD
• D. TFT

Answer: (D)

In a flat-panel detector, the switch that releases the collected charge is the thin-film transistor at each pixel. During readout, the transistor is driven on to connect the stored charge to the data line, allowing it to be read by the readout electronics. The scintillation layer simply converts X-rays to light, and the photodiode converts that light into electrical charge but does not act as the switch. A CCD is a different imaging technology and not the switching element in a typical flat-panel detector.

In a flat-panel detector, the switch that releases the collected charge is the thin-film transistor at each pixel. During readout, the transistor is driven on to connect the stored charge to the data line, allowing it to be read by the readout electronics. The scintillation layer simply converts X-rays to light, and the photodiode converts that light into electrical charge but does not act as the switch. A CCD is a different imaging technology and not the switching element in a typical flat-panel detector.