[Progress of imaging diagnosis for the cancer therapy--breast cancer]

As two main modalities for the breast cancer, ultrasonography (US) and mammography (MMG) were discussed about the efficacy and limitation of qualitative diagnosis. The accuracy rate of US and MMG for the breast cancer were 90.0% and 92.7% at the Aichi Cancer Center Hospital during these 2 years (1986-1988). The number of patients with the breast cancer is increasing recently in Japan. This cancer, however, is one of the curable cancer at the early stage. Therefore, it is very important thing to detect a small malignant mass less than 1cm in a diameter by using these modalities. In addition, the establishment of the mass screening system for breast cancer is desired. In order to make a precise diagnosis, it is necessary to add some devices on the ordinary modalities. For examples, mechanical improvement of the Moribuden tube with 0.1mm focus, operation of ductgraphy and cystography by double contrast method in MMG and application of 10MHz transducer in US. Furthermore, needle biopsy under US or X-ray is expected positively to make a fast diagnosis. On the other hand, DMR (Digital Mammo-Radiography) system has a bright prospect for the mass screening of the breast cancer in the respect of efficacy, cost and radiation hazard. DMR system has many advantages as follows, 1. The system is capable of bringing out clearly very minor differences of contrast. 2. Tumor shadows can be easily displayed. 3. The lateral projection only is sufficient (allowing examination of the chest wall also). 4. The X-ray dose is small: 0.03-0.05mSv. 5. The equipment is inexpensive to use. 6. Patient positioning is simple, and examinations take little time. 7. Long operator training programs are unnecessary. 8. The system uses digital signals, and so automatic diagnosis is possible. 9. Theoretically, at least, tumors as small as 0.2 mm in diameter can be detected.