A plastic step-block for testing film quality.
NIOSH 1975 May; :II-11-II-12
A discussion of the use of a plastic step-block for testing chest X- ray film quality. The requirements for film quality are intended to produce optimum films for diagnosis of coal worker's pneumoconiosis.
Occupational Medicine Symposia, Division of Occupational Health Programs, NIOSH, Rockville, Maryland, HEW Publication No. (NIOSH) 75-189