The latent image concept in computed radiography describes which of the following?

• A. release of energy from the fluorohalides
• B. stored energy within the fluorohalides
• C. number of x-ray photons leaving the patient
• D. interactions of x-ray photons within the IP

Answer: (B)

The latent image is the stored energy inside the phosphor crystals after x-ray exposure. In computed radiography, the imaging plate uses photostimulable phosphors (often europium-doped barium fluorohalide). When x-rays interact with these crystals, electrons become trapped in metastable states, creating a pattern that corresponds to the x-ray attenuation but remains invisible—the latent image. This energy stays stored until the plate is read, at which point a laser stimulates the trapped electrons to release their energy as light, producing the digital image. So the latent image concept centers on energy that is stored within the fluorohalide phosphors, not on energy release during reading or the immediate count of photons or initial interactions.