In the measurement of X-ray quantity in the diagnostic radiology, it is well known that the intensity at point along the central axis of the X-ray beam is inversely proportional to the square of the distance from the focus of the X-ray tube. However, we have often experience that the data are not adapted to the inverse square law, when we measure the output of the X-ray generator and the exposure dose. The main reason is the loss of ion recombination in a chamber. The ion loss is depend on the high dose rate of the X-ray beam, and on the electric field strength (volt/cm) according to the design of a chamber. In this paper, it will be discussed that the mean efficiency can be read easily from the Boag's graph as a function of the rate of the dose rate at two points.
Image processing by optical filtering technique is applied for enhancement of radiologic images. Generally, special techniques and equipment are required for this purpose. But the photographic masking method is practical because special equipment is not required. In this study, the masking method was investigated enhance radiologic images. The form of filters were examined and X-Ray pictures were processed by high-pass or band-pass filters. By those processed, details of bone structure, vessels and so on were clearer and sharper then original images.
It is known that physical system characteristics affecting radiographic image quality are configurated in sharpness, granularity and characteristic curve. In this paper, we pointed out to the radiographic mottle ; it is the dominant factor which affects radiographic image quality in the high sensitivity system like a image intensifier photofluolography. And we evaluated radiographic image quality from the data of granularity which derived from Wienner spectrum and Root Mean Square granlarity, for getting better radiographic image quality on concerning dose reduction.
The purpose of this study was to described the rationale and technique of stereoscopic magnification angiography. This method had advantages of both magnification angiography and stereoscopic angiography. Visualization of the small vesseles was apparently improved by the employment of this new method and the diagnostic value of angiography has been considerebly increased.
As one of the causes of variation of Thermoluminesence Dosimeter dose values, energy absorption of elements is considered. In the experiment, CaSO_4 : Tm with a high effective atomic number, BeO : Na with a low effective atomic number and Mg_2SiO_4 : Tb with an intermediate number were used. The elements were labeled, the label was directed towards the direction of irradiation with X-ray, and the dose was calculated after irradiation with X-ray in the diagnostic field. The surface of the element exposed to X-ray (use F), or the surface of X-ray passage (use B), was directed toward the direction of photomultiplier of the apparatus for measurement. When the dose on surface F of the element was assigned the Value of 100.0%, the dose on surface β was 80.0% to 86.5% in CaSO_4 : Tm, 94.2 to 98.8% in BeO : Na, and 92.6% to 93.1% in Mg_2SiO_4 : Tb. The difference between the average dose on surfaces F and β was statistically significan in CaSO_4 : Tm and Mg_2 SiO_4 : Tb but not in BeO : Na. The variation of measured values was less than 5%. In dosimetry requiring precision, therefore, the constant surface of the element should always be irradiated and measured, to obtain high precision.
We have tried to get choledocho-cho1ecysto graphy by direct injection of "Urografin, into a biliary tract on occasion of the surgery. In order to get a better choledocho-cholecystography, we researched on the human simulating model with gallstones. The results we obtained were as follows : (1) Minimal ga1lstone shadow recognigable on the film depends on the correlation between the R-kVp and the concentration of urografin. (2) When a large stone and small stones were overlapped eachother in the medium of "60%-Urografin., the shadow of large stone disappeared on the film and, on the contrary, the shadow which may have been accepted as the small stone, became visual. (3) We obtained theoretically following conclusion : in a certain latitude of cncentration of Urografin, the higher concentrated urografin we used, the smaller became the stone shadow to smaller stone shadow than original stone. We analysed theoretieally these phenomena and obtained some findings. The results may be applied not only to the choledocho-cholecystography at the surgical operation, ie, percutneous trans hepatic choleangiography or endoscopic retrograde choleangiography.
Conventional basilar projection of the skull is ordinarilly taken at suspensible position. Since this positioning gives patients much anxiety and pain, so it is difficult to obtain a satisfactory radiogram, especially in the case of aged people and infants. Then, we have tried basilar projection of the skull at lateral position, that is, we rotate a patient laterally to an angle 90 degrees to the couch surface and turn his face sideways. We use a fixing device of the meatal type on this occasion. And the patient sticks out his chin slightly. We expose X-rays in submento-vertical projection in this way. Moreover, we set a film parallel to anthropological plane, and the central X-ray is vertically exposed to this plane. We have obtained excellent radiograms using a cross-grid. The model of fixing device of the meatal type we used is made of foam styrol, wood, an aluminum plate and an acrylic board.
Technical studies of bilateral simultaneous retrograde brachial angiography for good visualization of the posterior fossa circulation were described. The patient was routinely examined in the Towne projection and simultaneous biplane radiography was used. A19-gauze thin-wall elaster needle was used for the puncture. Two automatic injectors (CISAL-I, Siemens-Elema) were required. Routinely, the injectors were filled with 30 ml of meglumine diatrizoate 65percent on each side. The injections were made simultaneously with an injection pressure of 6kg/cm^2. The method was easier to perform than catheterization and good opacification of the posterior fossa circulation was obtained.
The low extent of the cross-reactions due to the main circulation steroids indicates that radioimmunoassay by the new kit can be directly performed on dried crude extracts of plasma. A radioimmunoassay for the determination of plasma aldosterone is described simply. 1) extraction of aldosterone from 0.5 ml of plasma 2) incubation of the reaction mixture for 20 minutes at 37℃ and for 2 hours at 4℃ 3) absorption of free aldosterone on charcoal-dextran 4) centrifugation at 4℃ and counting of the supernatant However, in a pregnant woman or a patient treated with steroid-hormone, the purification is necessary to be achieved by paper (or column) chromatography. The trial produced paper chromatography box is very useful for these cases.
We have studied method of separation of bound and free type of T_8 by the use of PEG instead of DCC, and the results were as follows : 1) Reproducibility and recovery were also obtained good results. Mean coefficient of variation (CV) of accuracy of the measured T_5 was low level, 2.7% at 50-100ng/100ml, 3.0% at 100-300ng/100ml and 2.8% at over 300ng/100ml. Similarly, reproducibility of two different kit was 5.0%. 2) Recommended incubation time for the assay was two hours. 3) Dissociation of the PEG bound T_3 was found remarkably scarce in comparison with that of DCC bound T_3. 4) With high concentration of T_3 in serum, its value determined by PEG appeared fairly lower than T_3 value measured by DCC. 5) Analysis of sera from 24 normal subjects, 15 hyperthyroid and 6 hypothyroid patients yielded mean value of 149.8±24.4 (SD), 353.3±104.7 and 76.7±14.9 ng/100ml, respectively. T_8 levels in pregnant woman were a little higher than normal levels.
We have made bills about repairing our X-ray apparatuses and made notebooks for writing their conditions down. Then, we investigated them for last one year (from Nov. 1974 to Oct. 1975) and we got the numbe of troubles and of exchanged parts. The results are as follows : 1. The frequency of troubles of our X-ray apparatuses is 98 times a year; once per 3.7 days. 2. The number of exchanged parts amounted to 131. About half of them were relays, diodes and microswitches. We take this phenomenon as a matter of course because these parts are used in the the X-ray apparatuse so many. 3. The apparatus which became out of order most frequently was the one in the Xray-room No.8. It went wrong 26 times a year, that is, it didn't work for about a month during the past one year. 4. As for the systems of the X-ray apparatuses, the one which became out of order most frequently was the cassette changing system. It went wrong 24 times a year. The next one was the low-voltage system. The third one was the fluoroscopic or roentgenographic table and the high-voltage system was the forth. The troubles of the apparatuses are unavoidable, but we knew they had often occurred owing to a trifling one. It is important to check the apparatuses every day and keep them work good.