Dose efficiency of screen-film systems used in pediatric radiography.

Twenty-one screen-film systems were examined using contrast-detail-dose methods in order to determine which were most dose-efficient for use in pediatric radiography. With a given screen, dose efficiency in the noise-limited region (contrast approximately equal to 0.05) was more or less constant (within the range of experimental error) with changes in film speed. When screens with decreased phosphor thickness were used, dose efficiency deteriorated markedly. For a given speed of up to two times Par, rare-earth phosphors offered no advantage over calcium tungstate systems with regard to low-contrast dose efficiency; however, they did increase the speed of the system. Anti-crossover film proved to be an effective means of improving high-contrast detail while maintaining low-contrast dose efficiency.