Recentry external wounds due to traffic accidents and sports are on the increase under this circumstance, the establishment of an ailment-wise radiography method with the object of securing maximum radiographical information which not only contributes to the patiant care but also to QA (quality guarantee) of the x-ray image is a feasible proposition for the field of radiation technology. In this paper, we will present the process for establishing this ailment-wise radiography method in connection with plastic surgery and its results.
Formulae expressing the continuous spectra of x-rays radiated from a capacitor type x-ray apparatus with an inductance in the x-ray tube circuit are introduced and some calculated examples are shown. Continuous spectra radiated from a capacitor type apparatus having no additional impedance in the x-ray tube circuit, and a capacitor type apparatus with a protective resistance in the circuit and a wave tail chopping device are also calculated as references. (1) The continuous spectra radiated from an apparatus with an inductance lack the high photon energy portion which are contained in the ones from an apparatus without the inductance. (2) The continuous spectra radiated from an apparatus with a protective resistance and a wave tail chopping device have less energy fluence in the low photon energy region than the ones from the apparatus without the wave tail chopping device.
The management work in the film processing recently has become much more troublesome, because a largenumber of new types of film and of new type solutions are being rapidly introduced on the market. We have carried out a study on process properties of various types of film and various type solutions. A calibrate sensitometer was used for giving standard exposure for the various types of film. Each series of one type film consisting of 200 sheets of 10×12'size were processed in one type of developing solution, without an additional supply of the solution. Changing the process temperature within a range of 28℃ to 40℃, alteration of the density of the exposed film was measured. In another series, using various types of film, we made a degradation curve for each solution. The"TMG"film showed little change either in the temperature process change or in the degradation of the solution remarkably comparably to the alterations observed on other types of film. The"RD-III"solution showed little degradation for any type of film. This experimental condition is to be different from the process running daily, where a solution has to be much more degradated for a longer period of time. Further studies should be made under such daily conditions.
The metal input X-ray image intensifier (abbreviated to Metal I.I.) produced images much better than those of the conventional I.I. by the use of a glass window. Recently, a new type of metal input/fiber plate output X-ray image intensifier (abbreviated to metal fiber I.I.) was developed. This is provided with a thin metal window and a fiber optic screen substrate. Since the metal window reduces the scattering of X-rays and the fiber optic plate decreases the extension of light metal-fiber I.I. is greatly improved in the contrast and resolution of images. We have used this metal-fiber I.I. with the vascular procedures system. The clinical usefulness of metal-fiber I.I. has been fully demonstrated through improvements in image quality and diagnostic capabilities.
The X-ray film used for intensifying screens consists of silver halide grains of various size and having large dispersion. In conventional radiographs, film emulsion is blackened gradually from silver halide grains of large size and higher sensitivity to those of smaller size and lower sensitivity. In black-and-white reversal processing, larger size grains are mainly removed by bleach. It is thus expected that the final image of reversal-processed film will be formed by blackening of minute silver halide grains. Basing on this assumption, the image quality of reversal-processed radiograph was investigated from the staved point of spatial frequency characeristics, entropy and redundancy analysis. The radiographic granularity measured by Wiener spectrum showed reversal development to be better than conventional development at same density, and reversal development at high exposures and conventional development at low exposures to be advantageous. From the entropy analysis, optimum conditions under which transmitted information or the relative efficiency of transmission η is a maximum were found to exist for both conventional and reversal-processed radiographs. Also, from redundancy analysis, the reversal-processed radiograph at low subject contrast was better than conventional radiographs. Radiographs by reversal processing should thus prove excellent for clinical and detailed diagnostic purposes.