Abstract
Recently, the increasing breast cancer mortality has made the demand for early diognosis even more urgent, and we are concerned that the standardized technique of mammography has not yet been established. There are a few particular problems in the present method of mammography. One of them is, the poor contrast in the image on account of little difference in x-ray absorption of the soft tissue. Also, it is difficult to obtain suitable homogeneous x-ray graphic density because of the cone shape of the breast and its position. with the use of a special large capacity 'soft x-ray'tube with a glass window, and with the method of compensating the density of mammography byethyl alcohol, we have been able to obtain the image of the whole mamma in homogeneous density. As for positioning the flat mamma, which are more prevalent in Japan than in other countries, we attempted a new technique. By the use of a hollow parafin block and a cechil alcohol block, add with a suction pump, we were able to attract and form the mamma in place. These parafin and cechil alcohol blocks have two functions, namely, density compensation of the x-ray, and the forming of the mamma. We are confident that if the volume of the mamma attracting cavity of the density compensation block fits the mamma well, the effect of attraction will be very great. We have made a mammographic table from other works and have studied the ability of the intensifying screen and the grid ratio in the region of 25kVp-30kVp. The results are as follows : 1. In x-ray graphic contrast, the method of combining a back-screen and 4 : 1 grid ratio is better than the non-screen method. 2. X-ray exposure time by this method is 1/5 of that of the non-screen method.
