Which layer of a computed radiography (CR) imaging plate is responsible for creating the latent image?

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

Answer: (B)

The layer that creates the latent image is the phosphor layer. This layer contains the photostimulable phosphor material that absorbs X-ray energy and traps electrons in metastable states after exposure. The pattern of trapped electrons corresponds to the X-ray image, forming the latent image stored within this layer. The other layers serve supportive roles: the protective layer guards the phosphor surface, the conductive layer helps dissipate static charges, and the light shield layer prevents ambient light from erasing or activating the plate prematurely. When the plate is later read, a laser stimulates the trapped electrons to release their energy as visible light, which is detected and converted into the digital image.