Why must PSP plates be in light-blocking envelopes?

• A. Prevent light exposure
• B. Prevent radiation exposure
• C. Prevent dust accumulation
• D. Prevent heat buildup

Answer: (B)

PSP plates store a latent image in a photostimulable phosphor, and once exposed to x-rays they hold that image by trapping energy. Ambient light can release those trapped electrons and erase or fog the latent image, degrading image quality. Keeping the plate in a light-tight envelope prevents this unwanted light exposure until the plate is read, preserving the stored data. Radiation exposure during imaging is a separate issue handled by shielding and proper technique, not by the envelope. Dust or heat are less critical factors, but the primary purpose of the light-blocking envelope is to stop ambient light from fogging the image.