Which material in the sensor chain is responsible for converting X-ray energy to light?

• A. PSP
• B. Silicon
• C. ADC
• D. Scintillator

Answer: (D)

The first step in turning X-ray energy into a detectable signal is done by the scintillator. When X-rays strike the scintillator material, it absorbs part of that energy and re-emits it as visible light. The amount of light produced is proportional to the X-ray exposure, providing the initial optical signal in the sensor chain. That light is then detected by a silicon-based photodetector (like a photodiode, CCD, or CMOS) that converts the light into an electrical signal, which is finally digitized by an ADC. A PSP is used in a different radiography approach (computed radiography) and stores energy for later readout; it’s not the direct X-ray-to-light converter during exposure.