Which layer on a CR imaging plate primarily prevents unintended erasure of the latent image by ambient light?

• A. Protective layer
• B. Phosphor layer
• C. Conductive layer
• D. Light shield layer

Answer: (D)

Ambient light can erase the latent image on a CR plate because light can release trapped electrons in the phosphor layer. The layer that prevents this erasure is the light shield layer, which is opaque to ambient light and positioned to block room light from reaching the phosphor layer. By keeping light out, this layer preserves the stored image until the plate is read. The protective layer only guards the surface, the phosphor layer is where the image is stored, and the conductive layer aids electrostatic properties during handling and scanning.