ディジタルマンモグラフィにおける最適化撮影のための画質と被曝線量の検討 Discussion of image quality and patient dose for optimization of exposure conditions of digital mammography
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To optimize the target/filter combinations and tube voltages for the detection of low-contrast objects using full-field digital mammography system (FFDMS) Senographe DS (GE) under the conditions of a matched average glandular dose (AGD). Optimization of technical factors was carried out for acrylic breast thickness from 1.7, 3.7 and 5.7 cm, respectively. On each thickness of the phantom, exposure parameters (anode, filter, entrance exposure) recommended by Senographe DS were used as a standard radiation exposure for FFDMS. The AGD for standard radiation exposure in each breast thickness was calculated based on half-value layer and entrance exposure measurements. Beam current that matched AGD at each phantom thickness, while varying target/filter combinations and tube voltages across the full range available for FFDMS, was calculated. Contrast-detail (C-D) images were acquired under the constraint of matching the AGD for each breast thickness. C-D images were scored by observers. In general, there were no significant differences between C-D scores and technical factors (target/filter combinations, tube voltages) for FFDMS under matched AGD. However, our results indicated that the Mo/Mo anode-filter combination and low tube voltage were preferable for a thin breast, and Rh/Rh and higher kV preferable for a thicker breast. Our observer performance results indicate that the detection of low-contrast objects is optimized for FFDMS under constraint of matched AGD.
- Journal of The Society of Photographic Science and Technology of Japan
Journal of The Society of Photographic Science and Technology of Japan 68(Suppliment2), 33-34, 2005
THE SOCIETY OF PHOTOGRAPHY AND IMAGING OF JAPAN