Some method of regulation is necessery to maintain day-to-day control of developing and fixing and to keep the variations between various processing units to a minimum. I studied in relation to a degree of exhaustion of the developer, the charactristic curve by using the sensitometric strips and electric signal as variation of current against to the constant voltage. As the result, a degree of exhaustion of the developer had a settled margin of safety for sensitivity. The sensitivity dropped hastily just below the allowable settled margin. The sensitivity dropped hastily just below the allowable settled margin. The variation of sensitivity correspond with the electric signal. It is possible to control the developer automatically with the electric signal.
In high energy X and γ-ray (linacgraphy, cobaltgraphy etc.) absorption is depend upon the electron density of the absorbing material rather than its atomic number. Because of this, bone detail is not prominent but soft tissue shadows are better visualized. We selected the combinations of intensifying screen and X-ray film by using MTF, in order to improve the image quality of linacgraphy. In this paper, the radiographic localization of lesions for the proper place of the treatment are investigated, used mainly medical X-ray film. The results obtained are as follows ; 1. We had like to mention about intensifying screen, front screen was best compere with the double screen faced screens and back screen are worse when we consider MTF. 2. Lead screen was better than fluorometallic screen for the improvement of image quality and, it had few intensifying effect. 3. Industrical X-ray film of fine grain was given good image quality rather than medical one. 4. It is proper that film object distance should keep 15〜20cm since the Graedel-effect enlargement effect were contributed the improvement of image quality. 5. Exposure factors of linacgraphy are 0.5rad (that means 0.5sec) using front lead screen and medical X-ray film, and target-film distance is 1m. We can take linacgraphy of every part using this conditions.
The gonad dose was evaluated upon forty-six patients with the hyperthyroid treated with the therapeutic dose of ^<131>I, 2 to 20mCi, These forty-six patients have been derived from all the out-patients, 15787 cases, visiting the Chiba University Hospital in recent twelve years. The gonadal exposure due to gamma rays of ^<131>I was directly measured by the pocket chambers placed close to the gonad of each patient, showing 0.35 to 0.4 rad per one mCi of ^<131>I the first 24 hours after the administration. Those of beta-rays, however, were approximately estimated at 0.3 rad per one mCi by using the specific activities of ^<131>I in the blood and the calculation. The fundamental experiment concerning the gonadal exposure was perfomed with a body-sized phantom containing ^<131>I solution, suggesting that ^<131>I excreted into the bladder had gave considerable contribution to the gonad dose.
The breast bone is rather difficult part to obtain a good x-ray picture for diagnosis purpose by ordinary method. The contiguous photographing method of the breast bone by moving x-ray tube, which we devised, gives rise to tomographic effect. By this method, the lung markings and the neighbouring bones (ribs, thoracic vertebrae) are easily shaded oft, and besides, defect in the breast bone remains in good visualization. The technique of this method is not complicated, and this method is very convenient for daily examination to improve the diagnostic accuracy for the breast bone.
Res-O-Mat T_3 is used for an in vitro ^<131>I-T_3 diagnostic test to determining the T_3 binding capacity of serum. TBC index is obtained by comparing the quantity of T_3 bound by the patient's serum to that bound by pooled normal sera. Several basic experiments and clinical trials in 122 cases were performed. The results obtained are as follows : 1) Standard deviation of the results was 0.01,indicating reproducibility of this test to be satisfactory. 2) Decrease of TBC index was noted in the hyperthyroid cases with the increase of incubation time. 3) Increase of TBC index was noted in the hypothyroid cases with the increase of incubation time. 4) TBC index for the euthyroid cases was stable even when the incubation temperature was increased. 5) TBC index ranged from 0.87 to 1.06 (average 0.97) for 44 euthyroid, 0.55 to 0.97 (average 0.79) for 29 hyperthyroid, 1.12 to 1.25 (average 1.16) for 9 hypothyroid cases. 6) A good correlation between Res-O-Mat T_3 and ^<131>I-T_3 Resin sponge uptake test was observed.
Our hospital established the equipment of Toshiba's linear accelerator (LMR-13) in 1968. The maximum energy of this machine is 13 MeV and it's maximum output is 500R/min. We investigated the technical feasibility of supervoltage roentgenography (linacgraphy), because we thought that the linacgraphy would be utilized widely in diagnostic field in future. The purpose of our study is to improve the quality of linacgraphy in order to increase it's clinical value. Here we report the results of experiment as follows : 1. The energy of linacgraphy, we ordinarily use, is 6 MeV and the exposure conditions are for various regions as follows : chest posterior-anterior 0.15-0.2 sec., lateral 0.2-0.25 sec., nasopharynx 0.15 sec. The target-film distance is 2 meter. The patient receives for a chest exposure less than 1R. The X-ray beam is horizontlly directed in most examinations with up-right position. 2. We use an industrial film, Fuji type 100 and intensifying screens with lead foil 0.1〜0.5mm thickness (Kyokko GS or Toshiba RS). The lead foil reduces the number of very low energy of scattering reaching the film, in order to increase the quality of the linacgraphy. 3. The size of the focal spot of target is an important factor to produce sharpness of X-ray image. Our machine has a focal spot 3×5mm^2 in size. 4. We made a radiograpic filter for our diagnostic use instead of a therapeutic flatness filter. When we use it, we get higher out-put than ever. In conclusion, we describe the advantage of linacgraphy that the shadow of bone are reduced to a minimum and the shadows of underlying soft tissue or air-containing structure are better visualized. That is to say, it is possible to record clearly the structures of the mediastinum without losing any significant detail in the lung fields.