Experimental and clinical studies on the distribution of the contrast agents in vein indicate that the gravity plays a main role. As the hyperbaric contrast agents preferentially flow beneath the blood, posterior walls of the veins are clearly delineated contray to the poor visualization of the anterior walls in supine position. To avoid this disadvantage, the authors stressed that additional to supine, prone or upright lateral and anteroposterior projection were advisable.
The fine structural detail of the temporal bone is difficult to demonstrate in any direction by mean of ordinary roentgenography. Therefore, the tomography of the temporal bone has many advantages as postulated by Lemahieu (1952) for routine examination comparing to ordinary method. Curvilinear tomography, i.e, tomography with circular or similar symmetical movements, will give particularly good results in the examination of bone due to greater blurring of image other than focal plane and etc. Six projections of lateral, frontal, axial, Stenver's Owen's and Schuller's are selected for the precent study of the temporal bone by circular tomography. The best results were obtained in stenver's and axial projection for the three ossicles, in frontal projection for vestibule and internal auditory canal, in Owen's projection for canal, in Stenver's projection for pharyngo tympanic tube and in axial projection for temporal bone.
In the simultaneous bi-plane radiograph, side scattered x-rays from object have influence on another side film and they lower x-ray image quality on account of the fog. Using an automatic isodose plotter, we expressed the foggy films, for percentage of density, which was exposed by some exposure factors. And then we studied and compared the aspet of side scatters.
We examined in the simultaneous photography of mamma with low voltage magnification and contact. The minute focus X-ray tube for low valtage, the photographying bed and the film slide were made for this purpose. The sensitizing paper which only has the back was used for the magnifying photograpey and nonscreen for the contact photography. The magnifying power of three to four times is actually useful and greater power than this can never find any minute substanes. The magnifying photography showed the excellent results that the scattered rays decreased due to the Groedol efficiency, and minute lime precipitated images and fibrous index images were found which cannot be recognized by the contact photography.
In these some ten years, incidence of radiation hazard as well as the exposure of employed has decreased very much as the result of improvments in the construction of X-ray room, equipments and protection techniques. The results of nation-wide survey on the X-ray photofluorography at Health Centers conducted by the Ministry of Health and Weefare were analyzed with respect to the blood counts of the X-ray technicians and compared with normal healthy man. The results are summarized as follows : (1) The mean values for X-ray technicians in Health Centers of leucocyte ; erythrocyte counts and hemoglobin were 6,310±1,300,(472±54)×10^4 and 93.7±9.6%, respectively. Leucocyte counts and hemoglobin value are lower than normal values at 1% significant level. (2) Comparison between the technician and normal person for each age groups also showed significant lower values of blood counts in the technician expect in the age group over 50 years. (3) When geographical grouping were made, the variability of blood counts in the technician was smaller than in normal healthy person. However, the pattern of lower values was significant in the districts Tohoku, Kinki and Kyushu for the leucocyte count, Hokkaido, Shikoku and Kyushu for the erythrocyte count and Hokuriku and Kyushu for the hemoglobin value. (4) This study showed that 111 persons of the total 1,372 investigated technicians, (8.1%), were abnormal in view of the legislative standard for radiation hazard.