Report of the committee study on the dose and image quality in examination of breast cancer

The dose and image quality were studied in 104 facilities conducting mammography and factors influencing on those were analyzed. The purpose of the study was to make the domestic system of the quality assurance/quality control (QA/QC) of mammography for examinee. Each facility irradiated the QC mamma phantom RMI-156 and fluoro-glass dosimeter GD403 provided by the present committee with X-ray generator for mammography with Mo/Mo focus/filter system at 28 kV with auto exposure control mode. The phantom, dosimeter and film were sent back to the committee. Films were analyzed by 4 experts and dose was evaluated by the average glandular dose (Dg), which was DgN(V, HVL, T, P) x R, where DgN: normalized Dg, V: tube voltage, HVL: Al half value layer, T: pressed thickness, P: fat content of the mammary gland and R: irradiation dose. Choice of appropriate imaging equipment and DPE conditions, and education concerning the mammography QA/QC were pointed out important for getting the high quality image. (K.H.)