Which of the following components is NOT utilized in an indirect capture flat-panel digital image detector system?

• A. Photodiode
• B. Scintillation layer
• C. Analog-to-digital converter
• D. Photoconductor

Answer: (D)

In indirect capture flat-panel detectors, X-rays first encounter a scintillator layer that converts them to visible light, then the light is sensed by a photodiode that turns it into an electrical signal, which is finally digitized by an analog-to-digital converter. A photoconductor is used in direct-conversion detectors, where X-rays are converted directly into charge without producing light first. Because indirect systems rely on the scintillator-to-photodiode light-to-electrical signal path, a photoconductor is not utilized in this type of detector.