| We describe the results of dose measurements and image quality evaluation in mammography using a phantom for the ACR accreditation program. Screen-film images were obtained with the following systems: Min-R 2000 screen and Min-R 2000 film(Kodak), and UM Mammo Fine and UM-MA HC film(Fuji). CR images were obtained with the FCR 7000(Fuji). Compared with the Mo filter system, mean glandular dose with the Rh filter at 28 kV and 30 kV decreased 22% and 10%, respectively. However, at 32 kV and 34 kV, there was no significant difference between the dose with the Mo filter and that with the Rh filter. Area exposure product correlated well with entrance exposure dose and seemed to be useful for approximating glandular dose. Although the quality of images obtained with the Mo filter at 28 kV was acceptable, images obtained with the Min-R 2000 system were superior to those obtained with the other two. According to the mammography quality assurance program established by JSRT, mean glandular dose could be calculated by measurement of the entrance exposure dose for a mammographic phantom. |
