Assessment of subject doses in mammography and its implication in the screening practice

The aim of this paper is to evaluate the equivalent dose to breasts and effective dose from typical mammographic procedure. To calculate the contribution to effective dose from scattered radiation was used an MIRD-type whole body phantom of adult female. In this study, transformed the original MIRD female breast model to simulate the compressed breast. To determine the size of breast, mammographic procedure data were collected from the Korea Cancer Center Hospital in Seoul. These values were applied to the geometrical modeling of compressed breast. Mammographic units chosen for modeling are GE Senographe 600T and LORAD M-IV. Dose assessment was conducted for breast material of gland, homogeneous 50:50 mixture of adipose and glandular tissue, and sole adipose. Patient doses were calculated using the general-purposed Monte Carlo code, MCNPX. The X-ray spectra provided by the SPEC 78 data library were used. The difference in breast dose due to the different breast material compositions and different units was small. The equivalent doses to the breast were decreased aat other ages to became 2.25 mSv for patients undergoing craniocaudal in their 20's and the lowest dose is 0.68 mSv undergoing craniocaudal in their 60's. Similar trend was observed in the mediolateral projections. The contribution of other organ doses to effective does is found negligible so that the effective doses were approximately one-tenth the breast dose. The result of assessment of subject doses in mammography may provide reference of screening practice and groundwork for the national health in radiology