A COMPARISON OF TWO DIFFERENT PROCESSING CHEMICALS FORMAMMOGRAPHY: REPERCUSSION ON DOSE TO PATIENTS

摘要

The main technical objective of screen-film mammography is to reach the best image quality with the lowest dosernto the breast. Sensitometric gradient and speed are factors related with both subjects respectively. For a givenrnchoice of film, these factors are affected by processing variables. By this reason, manufacturers have developedrndiferent types of films that are recommended for particular processing conditions.rnThe purpose of this work is to compare the variations of both sensitometric characteristics of mammographicrnscreen and film systems induced by two different manufactured chemicals: RPX-Omat EX/LO (Kodak) andrnG139/G334 (Agfa). A comparison of thirteen mammographic films by means of light sensitometry wasrnperformed at different processing conditions: 90s/Kodak, 120s/Kodak, 180s/Kodak, 90s/Agfa, 120s/Agfa andrn180s/Agfa. Secondly, 99 combinations of screens and films were evaluated by X-ray sensitometry at 120s/Kodakrnand 120s/Agfa processing. At light sensitometry, variations in processing time led to different modifications inrnfilm speed, depending on the chemicals used. At X-Ray sensitometry, Agfa chemicals induced higher values ofrnsensitivity for almost all combinations, while Kodak chemicals gave higher gradient/speed quotient. The resultsrnshow that dose to patients in mammography and image contrast are highly dependent on the chemicals selected atrnmedium cycle (120s) processing.