SCREEN LAG refers to:

SCREEN LAG refers to:

• A. static electricity
• B. focal spot blur
• C. phosphorescence/afterglow
• D. light diffusion

Answer: (C)

Screen lag is the persistence of light emission from the phosphor layer after the exposure ends. The phosphor stores some energy during x-ray exposure and slowly releases it as light, creating a faint afterglow that can appear on subsequent images or cause a ghost image on the same image. This is different from static electricity (electrical discharges), focal spot blur (geometric blur from the focal spot size), or light diffusion (light scattering within the screen). Understanding lag helps explain why older screens show lingering images and why newer phosphors are designed to minimize afterglow.

Screen lag is the persistence of light emission from the phosphor layer after the exposure ends. The phosphor stores some energy during x-ray exposure and slowly releases it as light, creating a faint afterglow that can appear on subsequent images or cause a ghost image on the same image. This is different from static electricity (electrical discharges), focal spot blur (geometric blur from the focal spot size), or light diffusion (light scattering within the screen). Understanding lag helps explain why older screens show lingering images and why newer phosphors are designed to minimize afterglow.