Investigation into Factors Influencing Fuji S-Value Using an Extremity Phantom

Exposure indices are provided by manufacturers to give an indication of exposure for computed radiography (CR). Although there are recommended ranges for exposure index values for various examinations, they may be affected by a number of other factors in addition to exposure. This study using an extremity phantom found collimation to be the most important factor influencing the S-value for a Fuji CR system. It is therefore essential that collimation is kept as tight as possible without excluding relevant anatomy. CR imaging plates should be processed rapidly after exposure to prevent loss of information stored in the latent image. The reliability of the S-value exposure index as an indicator of exposures can be increased with better understanding of how it works, and by practical application of this knowledge to radiography.