When X-rays strike a photostimulable phosphor material, _____________ is released.

• A. Electrons
• B. Protons
• C. Neutrons
• D. Photons

Answer: (A)

When X-rays interact with a photostimulable phosphor, they impart energy that frees electrons from their bound states. Some of these electrons are captured in metastable traps inside the phosphor, storing energy for later. This stored energy is then released as visible light when the plate is later stimulated (read out) by a laser, causing the trapped electrons to return to lower energy levels and emit photons that form the image. Protons or neutrons aren’t the particles released in this process, and while photons are produced during readout, the immediate release caused by X-ray exposure is electron liberation and trapping.