What type of phosphor material is typically found in the storage screens used in Computed Radiography (CR)?

What type of phosphor material is typically found in the storage screens used in Computed Radiography (CR)?

• A. Europium activated barium fluorohalide (BaFl:Eu)
• B. Calcium tungstate
• C. Strontium bromide
• D. Cadmium sulfide

Answer: (A)

The correct response identifies europium activated barium fluorohalide (BaFl:Eu) as the phosphor material commonly used in storage screens for Computed Radiography (CR). This phosphor is particularly effective due to its ability to absorb X-ray energy and then release it as visible light when stimulated by a second light source, typically a laser during the readout process.

This characteristic is essential in CR systems, as it allows for the conversion of X-ray information into a digitally reconstructable format. The europium activator enhances the luminescent properties of barium fluorohalide, providing high sensitivity and resolution, making it well-suited for medical imaging.

The other options, while they are phosphors used in other contexts, do not serve the same purpose in CR systems. Calcium tungstate, for example, was historically used in traditional film-screen systems rather than in the modern digital context of CR. Strontium bromide and cadmium sulfide are also not typically employed in CR technology, serving different applications or historical contexts in imaging. Thus, europium activated barium fluorohalide remains the standard due to its performance characteristics specific to the needs of Computed Radiography.