A system that used scintillators that convert X-rays to light, light to electric charge, and store the charge in capacitors is known as a:

• A. CCD
• B. CMOS
• C. Photodiode
• D. Film-screen

Answer: (A)

When X-rays are first turned into light by a scintillator and that light is then converted into electric charge stored in tiny capacitor wells, you’re looking at a CCD-based indirect detector. In this setup, the scintillator (like CsI or gadolinium oxysulfide) emits visible light in response to X-ray photons. That light is captured by a CCD, whose pixels act as charge storage sites; each pixel accumulates charge proportional to the light it received. During readout, the stored charge from each pixel is transferred and converted to a digital image. This combination—scintillator for light production and a CCD that stores charge in capacitors for image readout—is the defining feature of the described system. Film-screen uses chemical changes on film, and a photodiode alone doesn’t inherently store the image as capacitive charge in a grid, while CMOS detectors use a different architectural approach.