Which modality uses photostimulable phosphor plates to capture the image?

• A. Computed Radiography
• B. Direct Digital Radiography
• C. Film-screen Radiography
• D. Digital Fluoroscopy

Answer: (A)

Photostimulable phosphor plates are the imaging medium unique to computed radiography. When you expose the plate to X-rays, the phosphor material stores energy as a latent image. In a CR system, the plate is then placed into a reader that scans it with a focused red laser. The stored energy is released as light (photostimulated luminescence), and this emitted light is captured and converted into a digital signal to form the radiographic image. The plate can then be erased with bright light and reused.

This differs from direct digital radiography, which uses a solid-state detector that captures and transmits the digital signal immediately, with no separate plate or laser readout. Film-screen radiography relies on silver halide film and chemical processing to develop the image, not a digital readout. Digital fluoroscopy provides real-time moving images using a different detector system, not a stationary plate read by laser.