Dual-energy subtraction mammography was performed for breast examinati
ons. To obtain a dual-energy subtraction image with a digital radiogra
phy unit, high- and low energy images were obtained at an appropriate
time interval under different x-ray exposure conditions. In about 50%
of the patients with breast cancer included in this study, we obtained
better diagnostic accuracy with dual-energy subtraction images than w
ith conventional mammography. In some cases of breast cancer, it was p
ossible to diagnose intraductal spread of this lesion on the subtracte
d images. Furthermore, abnormal lesions commonly observed on mammograp
hy in cases of fibrocystic disease tended to be erased on subtracted i
mages. Thus, dual-energy subtraction mammography provided useful infor
mation for diagnosing breast diseases. However, there were several cas
es in which the subtracted images lacked sufficient image quality, and
several technical problems with subtraction are thought to remain. Co
pyright (C) 1995 by W.B. Saunders Company