The author had some doubts about the effects of the general method with grid to eliminate scattered radiation in high voltage radiography. He measured the changes in degree of scattered radiation with increase of tube voltage and examined ways of absorbing scattered X-ray, adapting the degree of scattered radiation. Good results were obtained in out line.
In this 9th report, the influence of intensifying power on X-ray photographic contrast was studied ; high intensifyingscreen "Kyokko" HS and low intensifying screen "Kyokko" FS were used in the comparative study and examined by the tangent of the Al absorption wave within the tube voltage between 60kV and 120kV ; to verify the result, they were also examined in chest radiography. The following result wasproved ; degree of contrast under various intensifying powers depends not on the intensifying screen itself buton the condition of radiography in which the screen is used.
In tomography, the nearer the lightened shadow of the unnecessary object is drawn to the blurring of the tomographic image, the easier becomes the interpretation of tomography. The blackening was examined in theory ; the relation of blackening with distance between unnecessary object and shaft and with the length of blurring of unnecessary ofject was studied. Moreover, the effect of various tube voltage on the quality of tomography was discussed.
The author studied and reported here on the following problems ; 1) To what extent penumbra due to the size of focus can be eliminated by lengthening the distance between object and focus. 2) How the resolving power changes with the changes of the size of focus and the length of distance between object and focus.
The semi-high voltage radiography at charged voltage 90kV and at dischaged voltage 87-89kV by the condenser dischaged type X-ray apparatus in which a triode-controlled shutting method was applied, was compared with the high voltage radiography at 120 kV by the transform type apparatus and the following result was obtained ; the former stands comparison with the latter in showing contrast in bone. And the scattered radiation in the former is relatively little and can be eliminated by a small grid ratio.
Concerning the residual voltage after discharge in X-ray apparatus discharged type that gives an electric shock, the changes of residual voltage in proprotion on the change of charged voltage and in course of time after discharge was measured reported here.
Complete grounding to prevent electric shock is an important problem in radiographic work. In the case of fluosography which demands many movements of the apparatus, complete grounding is sometimes difficult. Concerning the earth poles of several apparatus, the effect was experimentally measured in various instances with Kohlarausich's bridge and L-9 type earth resistance meter and the following results became clear ; it is sometimes difficult for the effect of the earth to reach to the value of 3rd Ground Wire Work desided in the Provison of Electric Works.
The general methods of radiography of the bladder have been insufficient to diagnosis the fundus and posterior wall of the bladder and have been unable to satisfy the recent demands of the field of urology. The author contrived and reported here a way of synthetic diagnosis of bladder lesions which is the combination of five methods, i.e., anteriorposterior, "Takayasu-Nishiura "-midification, basal, axial and dorsal cystography with injection of X-SOL (barium sulfate) into the bladder.
In radiography of the patella, a distinct full image is very difficult to obtain because of the anatomical position and only lateral images have been used. It is proper, however, that a full image should be used in detailed radiography of the patella. Taking a radiogram of the patella from two direction, posterolateral and posteromediar, with the application of a modification (Kaikaku Satsueiho), a distinct full image was obtained with radiography of the detailed structure of the patella.
To rationalize the radiography of patients in plaster casts, basic studies were made as follows ; Coefficients of exposure of phantoms in plaster casts in several thichneses were measured and from the results, a table was made to facilitate calculations of the best condition for radiography of patients in plaster casts. Satisfactory results were obtained clinically.
In the contrast radiography of the parotid, a distinct image is difficult to obtain because of the overshadowing mandible and cervical vertebrae. The author examined the posture of the patient and incident angle of normal X-ray with a positioning board and special cone and obtained satisfactory results. The contrast media to be used for it were also investigated.