[Digital mammo-radiography (DMR) in mass screening for breast cancer]

There are still many problems to be overcome in the development of mammographic apparatus suitable for mass screening purposes, but a certain number of these have been solved in the system discussed in the present paper. The equipment employs the technique of displaying I.I. images on a monitor by means of an image processor. This possesses the advantages of both film mammography and xeromammography, and the X-ray dose involved is small. The following advantages over film mammography are offered: The system is capable of clearly bringing out very minor differences of contrast. Tumor shadows can be easily displayed. The X-ray dose is small: 0.03-0.05 R. The equipment is inexpensive to use. Patient positioning is simple, and examinations take little time. Long operator training programs are unnecessary. The system uses digital signals, and so automatic diagnosis is possible. Theoretically, at least, tumors as small as 0.2 mm in diameter can be detected. The future goal is discovering unpalpable breast cancers. DMR is useful because of low dose, low cost and high safety. In our study as screening for breast cancer, DMR system shows high sensitivity (87.1%), specificity (78.7%) in 391 cases of out patients.