Mammographic screening for breast cancer was recommended in a notification issued by the Japanese Ministry of Health, Labour and Welfare (Notification Roken No. 65) in 2000. To reduce mortality due to breast cancer, the Central Committee on Quality Control of Mammographic Screening (Central Committee) was organized by six screening-related societies in 1997, and attempts had been made to establish a quality control system before Notification Roken No. 65. The Education and Training Committee and the Mammography Facility Image Evaluation Committee were created by this committee. Physicians and technicians who are approved in the training course then receive certification by the former committee. Image evaluation was started in 2001. Initially, only screen-film (S/F) images were evaluated ; however due to the increase in the use of digital mammography systems, the evaluation of digital images (hard copies) was started in 2004 based on the same criteria as those for S/F images. In this paper, we describe (1) changes in image quality evaluation methods, (2) changes in image quality evaluation, and (3) changes in the numbers of evaluations of digital and S/F facilities.
Control of mammographic screening is being developed. However, the number of systems that have undergone facility image evaluation is approximately 1,000, which accounts for only one-third of all installed systems. It would be desirable for all facilities conducting mammographic screening as well as detailed mammography examinations to undergo facility image evaluation.

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Since the differences in X-ray absorption between various breast tissues are small, a dedicated X-ray system for examination of the breast and a high-contrast, high-resolution screen/film system (SFM) (light-receiving system) are employed for X-ray diagnosis. Currently, however, there is a strong trend toward digital imaging in the field of general radiography, and this trend is also reflected in the field of mammographic examination. In fact, approximately 70% of facilities purchasing new mammography systems are now selecting a digital mammography system (DRM).
Given this situation, this report reviews the differences between SFM and DRM and discusses the radiographic techniques and quality assurance procedures for digital mammography.

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Both the axial and lateral resolutions of ultrasonography have recently been greatly improved, owing to complete digitalization of the machine as well as narrowing of the beam width and adoption of high frequency band scanners. Particularly for ultrasound examination of areas close to the skin surface, high frequency band scanners are useful because they enable detection of minute lesions only a few millimeter in size.
On the other hand, the treatment of breast cancers has generally tended to focus on minimizing the extent of surgical resection, because of the introduction of sentinel node biopsy, popularization of minor surgery preserving the breast, and tailor-made individualization of postoperative adjuvant therapy. Thus clinicians in this field have made increasing efforts to detect breast cancers at an early stage, including DCIS, and high-quality ultrasonography is expected to be a useful tool for this purpose.
In order to detect very tiny lesions, an extremely high-quality ultrasonography machine and skilled operation are required. Examiners can now finely control functions that are important for quality control, such as the receiving frequency, gain and frame rate, and images are displayed on a monitor and recorded as a printed picture.
The completely digitalized ultrasonography machine now mainly used employs electric focusing, by which signals sent from receiving probes can be managed by controlling the timing through a delay circuit, instead of focusing by means of an acoustic lens. By using this mechanism, the quality of images has improved. The delay circuit fixes the received sound speed at about 1,530m/s or 1,540m/s, calculates the delay time, and forms an electrically focused image. The fat content of the breast differs among women ; sound speed is slower when the breast is rich in fat and higher when fat is sparse. Thus the grade of the delay circuit changes according to differences in breast fat content, and image blurring can occur. The type of machine that has been widely adopted has a “beam compound system”, which radiates sound in many directions to make an image, and therefore blurring is increased.
We have found experimentally that controlling the speed of sound received actually yields a change in image quality. By comparing blurred images due to differences in sound speed with improved-quality images as a control, we wish to stress the usefulness of this newly developed function, by which sound speed correction can be performed, and employed to detect tiny lesions during ultrasound scanning of the breast.

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To maintain a sufficient number of qualified reading doctors for breast cancer mammography screening, we have held training courses across the nation. Grade-up examinations have been carried out for doctors who had failed to attain grade A or B at the training courses. We have evaluated the quality assurance of the examinations via questionnaires and reported the results on 7 previous occasions.
In the present investigation, we reviewed all answers obtained from questionnaires at the previous 19 examinations, from the first one (November, 2000) until the last one (March, 2007). There were a total of 3,380 applicants, of whom 402 (11.9%) obtained grade A and 2,008 (59.4%) grade B. Thus a total 2,410 applicants (71.3%) obtained either A or B, and this rate was considerably superior to the 56% obtained in the first three examinations, although the former rate included the results of repeated applicants (Report No. 4). These good results may have been due to an increase in the quality of the training courses and may have been affected by conducting the examinations not only in Nagoya but also in Tokyo and Osaka.
In a period of about 10 months after April, 2004, the certification standard was increased and a system of certification reappraisal every 5 years was adopted. At that time, more than 75% of all applicants were A- or B-certified doctors at the 9th and 10th examinations, and the good results might have reflected the fact that many doctors tried hard to maintain a high reading ability.
In February, 2005, the certification standard reverted to the previous one for various reasons, and the rate of A- or B-certified doctors decreased.
In October, 2006, the examination changed from 100 questions concerning one-direction mammography to 50 one-direction questions and 50 two-direction questions, because of the adoption of two-direction mammography to age 40 years.
Since it was widely recognized that the second reading at breast cancer screening should be done by A-certified doctors, many applicants tried to attain grade A after the 15th examination. As a result, the rate of A- or B-certified doctors increased.
An every 5-year reappraisal system will again be adopted in 2007. We must recognize the importance of the original aim of screening to find curable cancers and further increase the quality of examination.

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One hundred eighty-five cases of primary breast cancer cases treated surgically at our hospital between January 2001 and December 2005 were divided into three groups based on the disease state at the time of discovery. These three groups included 40 asymptomatic cases detected by breast cancer screening (screening group), 23 cases of benign conditions detected at follow-up (follow-up group), and 122 cases detected as a result of symptoms (symptomatic group). These groups were then evaluated retrospectively to assess the usefulness of ultrasonography (US) for breast cancer detection.
The average tumor diameter was 14.0mm in the screening group, 10.8mm in the follow-up group, and 24.6mm in the symptomatic group. In these groups, the sensitivity of US was 90.0%, 95.7%, and 100%, respectively, when each category over 3 was considered as positive. The sensitivity of mammography (MMG) was 85.0%, 73.9%, and 96.7%, respectively. Among three cases that were false-negative by US, two were due only to microcalcification and all three were categorized as 2. The average tumor diameter in 16 cases that were false-negative by MMG was 12.9mm, and all were invasive cancers.
The present results indicate that the sensitivity of US is superior to that of MMG for diagnosis of breast cancer. Regular follow-up using US is thought to contribute to the early detection of small invasive cancers. US is complementary to MMG for detection of breast cancer, and therefore the two techniques together are thought to provide better screening sensitivity.

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The American Cancer Society has reported that mammographic high density corresponding to breast cancer is RR>4.0. There are some reports that hormone replacement therapy (HRT) influences MMG density, but many of those studies used Wolfe's classification. We used a same condition MMG as pre-HRT. We examined changes in MMG density before and after hormone therapy (HT), and found that MMG density was higher in women receiving HT than in those receiving no treatment.

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Milk-rejection sign occurs when an infant, who has been nursing since birth from both breasts, abruptly refuses milk from one breast. A malignant mass is later discovered in the lactating breast rejected by the infant.
Here we describe such a case in a 41-year-old woman who had been nursing her 29-month-old son from both breasts since birth. The son complained that milk from the right breast “tasted bad”. The mother noticed an induration in the rejected breast after milk-rejection sign had been initially observed, but the patient attributed this hardening of the tissue to plugged ducts. Five months later, nipple discharge appeared bloody. Six months later, she was diagnosed as having breast cancer and admitted to our hospital. The mass had spread in the upper part of the breast. The patient underwent a modified radical mastectomy. Histological findings showed that the tumor was mainly intraductal papillotubular carcinoma with a small area of focal invasion.
The reason for milk-rejection sign is speculative, but is probably related to biochemical substances in the milk that alter its taste or odor. Elucidation of the biochemical substances present in the milk of a diseased breast and increased awareness of the milk-rejection phenomenon would contribute to early breast cancer detection during lactation.

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