As more local governments adopt mammography for breast cancer screening, the shortage of qualified doctors skilled in interpreting mammograms must be resolved. Local medical associations, local governments, hospital medical departments, and other groups interested in breast cancer screening are expected to hold more mammogram training courses under the joint auspices of the Central Committee for Quality Control of Mammographic Screening (CCQCMS). The Subcommittee for Education in the CCQCMS has distributed questionnaires since the first training course in Osaka, in order to assess the quality of the training courses and to provide more effective programs based on stratification of participants by experience. In this study, eleven training courses held before March 2001 were reviewed to see how the participants in α-rank courses (for beginners) could obtain higher results. The percentage of doctors who obtained grades A or B in α-rank courses (4 courses) was 31-56%, lower than that for β-rank (4) and γ-rank courses (3) (for more experienced doctors), except in Nagoya 1 (α-rank). In Nagoya 1, achievement was equal to a γ-rank course ; among level1 (with the least experience) doctors, 17% (8% of all participants) obtained grade A, and 67% obtained grade B (33% of all). Ninety percent of the participants obtained grade A or B. Answers to questionnaires revealed that many beginners in Nagoya had regularly participated in workshops on mammogram interpretation. This indicates that attending workshops in Nagoya-style or small-scale training courses before the larger training course helps to improve performance in an α-rank training course.

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We investigated 501 cases of breast cancer with a tumor diameter of 2.0 cm or less in our clinic between April 1988 and December 2000, and also studied prognoses in cases showing metastasis to the lymph nodes. Of the 501 cases, 81.8% had no metastasis, 13.4% had 1-3 metastases, 2.2% had 4-9, 0.8% had over 10, and 1.8% revealing metastasis at initial examination. The metastatic ratio based on tumor diameter was 3.5% with 1.0 cm diameter, 21.8% with 1.1-1.5 cm and 23.2% with 1.6-2.0 cm. The ratio for those of 60 years or older was about half of those less than 59 years old. The ratio based on histologic type was 1.3% in tumor diameters of 1.0 cm, at 3.0% ; the highest with in scirrhous carcinoma. Where diameters exceeded 1.1 cm, the rate was about 10% in mamilliductal carcinoma, 32% in scirrhous carcinoma, and the median rate was noted in massive ductal carcinoma and other specific types.
There were 22 recurrences (4.4%) after surgery, and a higher rate was noted in those with lymphatic metastasis. There were 16 cases with distant metastasis, 6 with focal recurrence. The recurrence rate among elderly patients was low. During the follow-up period of 72 months, the survival rate was 96.8%, including three deceased cases due to other diseases.

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Quality control is one of the most important aspects of breast cancer screening. Since mammographic screening was started by the Ibaraki Health Service Association in 1995, semi-annual conferences have been held to monitor the quality of the screening. Mammograms classified by screening between April 1998 and September 1999 as Categories 4 and 5 were discussed in a subsequent conference. Ten of those cases had been diagnosed as normal or benign in the hospitals. We requested each hospital to reconsider the cases. As a result, three cases of breast cancer were found. We emphasize here that the whole screening process must be subject to stringent quality control. Conferences allow better understanding between the screening facilities and the hospitals.

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Guidelines for breast cancer screening using mammography in women aged 50 years and over were announced by the Ministry of Health and Welfare in 2000. We tested the effectiveness of mammography for breast cancer screening in a study funded by the Ministry between 1998 and 1999, through the Sendai City Medical Association. The subjects were 2, 285 women aged between 50 and 69. Firstly, MLO imaging was performed on both breasts. The patient then took the mammograms to an individually chosen private practice for reading and a clinical breast examination. Finally, the mammograms were collected in the screening center and read by specialists in mammography.
Overall recall rate was 4.5% ; the rate from clinical breast examination was 1.0%. Seven breast cancers were detected in 2, 285 subjects by the specialists with the doctors in private practice detecting four of the cases. Six of the seven cancers were node negative. Five months after screening, one woman was diagnosed as having breast cancer. The sensitivity, specificity and positive predictive values of the screening were 87.5%, 95.8% and 6.8%, respectively.
The introduction of mammography for breast cancer screening in private practice is likely to rise and contribute to a higher level of breast cancer screening nationwide.

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The results and problems related to the introduction of screening mammography were investigated. Screening mammography was performed on 6, 809 women in St. Luke's Center for Preventive Medicine between April 1999 and March 2000. Patients in the mammography group received clinical breast examination and screening mammography (MLO and CC views). A physical examination alone was done for the rest of the patients, who made up the PE group. The mammographs were interpreted by five experienced radiologists, using the following groupings : normal, benign, dense breast (DB), further examination (FE), needing biopsy (NB) and needing treatment (NT). All patients pointing out a breast mass after self-examination or classified as DB, FE, NB or NT were referred to a breast surgeon to assess malignancy. Of the 2, 579 mammography group patients, 703 were referred to our department, and 588 (83.6%) were examined. Breast cancer was diagnosed in 10 cases. Of the 4, 198 BE group patients, 125 were referred to a surgeon. Ninety patients (72.0%) were examined and breast cancer was diagnosed in six cases. The cancer detection rate was significantly higher in the mammography group than in the PE group (p =0.043). DCIS (ductal carcinoma in situ) and T 1 breast cancer was diagnosed in the mammography group more often than in the PE group (p=0.071, 0.077 respectively). We found that each radiologist interpreted the tests slightly differently. From this we recommend that education and training in the standard classification of screening mammography be made mandatory.

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It has been widely accepted that increasing the optical density of clinical mammograms would possibly achieve higher contrast. Using 5 X-ray mammography units, series of images with optical densities ranging from 0.7 to 2.1 were obtained to investigate the dependence of radiographic contrast on image optical density. The technical factors investigated were an RMI-156 phantom, a moving grid, Mo/Mo, 0.3 mm focus, 28 kV, MinR 2000/MinR 2000, processing time of 90 s and processing temperature of 32-34.2°C. Pixel values measured on digitized images were converted to optical density using a calibration curve, and radiographic contrast was evaluated for a disk, calcification specks and masses.
The results of 5 series of images showed a consistent relationship between radiographic contrast and optical density, indicating that the radiographic contrast would be effectively improved for test objects with a high object contrast, such as disks or specks, by increasing the optical density of the images. On the other hand, the gain in radiographic contrast was small for objects with a low object contrast. These experimental results were supported by theoretical estimation based on the film characteristic curve. The correlation coefficient between measured and estimated contrasts was 0. 987 as an average of 5 series of images.
It is concluded that increasing the image optical density has only limited efficacy for detecting low-contrast breast masses embedded in glandular tissue.

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Quality control of the image is one of the most important elements in mammography. Assessment is generally carried out by visual evaluation of the phantom image. A photographic density of the phantom image of over 1.2 is formally recommended. However, the value of 1.4 has recently been proposed. This paper examines the relationship between visual evaluation and the photographic density of the phantom image. Visual evaluation was significantly improved using density levels of 1.4. However, image quality was greatly affected by film base density, image characteristics of the screen-film system, film contrast and the brightness of the viewing box. The evaluation of breast masses was particularly improved using the highest brightness of the viewing box.

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We performed breast cancer screening using mammography and ultrasonography, combined with clinical breast examination in individuals attending for voluntary general medical check-ups. Of 11, 480 subjects screened, 757 subjects (6.6%) were recalled for closer examination, with 48 subjects subsequently diagnosed as having breast cancer, 29 of them in the early stages. Conservative surgery was performed on 20 of these patients.
Detection rates were 0.04%, 0.56%, 0.44% and 0.54% in subjects aged 30-39, 40-49, 50-59 and over 60 years. As there was a sharp increase in subjects over 40, we consider breast cancer screening most appropriate for women aged 40-49 years. Detection rates in a sample of 48 patients by clinical breast examination, ultrasonography and mammography were 33.3%, 89.6% and 70.8%, respectively, indicating that ultrasonography is more useful mammography in screening for breast cancer. Ultrasonography and mammography would be the most effective approach to breast cancer screening.

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