Comparison of Image Quality and Mean Absorbed Dose to the Breast for Two Mammographic Films

Abstract

A film intended for mammography (Kodak SO 155 MRH-l) was tested and compared to one (Kodak SO 177 Ortho M) used earlier.Both films including the cassette could resolve 20 Ip/mm. For a processing time of 90 s the new film gave the same overall image quality and irradiation dose to the breast as the old system. If, instead, the processing time was increased to 150 s, a 43% reduction in kerma could be attained with the new film. With a developing temperature of 36°C and 150 s processing time, the noise is clinically acceptable. A nonparametric test showed no significant difference between the 2 films on the 0.01 level. At an X-ray tube potential difference of25 kY,the mean absorbed dose to a 4.5-cm-thick breast was reduced from 1.7 mGy with the old combination to 1.0 mGy with the new one. The measurements were made with a moving grid.