What does a photostimulable phosphor store during X-ray exposure?

• A. Light energy
• B. Heat
• C. X-ray energy
• D. Electrical charge

Answer: (C)

When the photostimulable phosphor is exposed to X-rays, the photons transfer their energy to the phosphor and create traps in the crystal lattice where electrons can be held. This stores the energy from the X-ray exposure as trapped electrons, forming a latent image. Later, scanning with a laser releases those trapped electrons, and the released energy appears as light to read the image. So the energy stored during exposure is the energy from the X-rays themselves, captured as trapped electronic states in the phosphor.