What triggers the release of light from a PSP after exposure?

• A. Electrical current
• B. Magnetic field
• C. Pressure
• D. Light stimulation

Answer: (D)

Light stimulation is what triggers the release. After x-ray exposure, the PSP stores energy in trap sites within the phosphor crystals. When the plate is scanned with a laser (visible light), the trapped electrons are released and return to ground state, emitting light in the process. This emitted light, known as photostimulated luminescence, is detected to form the image. The other options wouldn’t produce the readout: electrical current, magnetic field, or pressure don’t cause the stored energy to be released in a controlled way for imaging.