The material and thickness of an additional filter have been investigated for angiography. The resule is that the copper filter reduce effectively, the patient dosage with little increase in tube loading. The 0.15-mm copper filter reduce skin exposure 35% using the 1.0-mm aluminum filter for abdominal angiography. The 0.15-mm copper filter achieves an exposure reduction as much as the 0.12-mm gadolinium filter with about 30% less tube loading under the same iodine contrast.
Some methods were devised for fitting the X-ray film characteristic curve. The usually measurement value has some errors, so we considered the approximation method was superior to interpolation method. We attempted an approximation of the X-ray film characteristic curve by using the Fourier Series method. Fundamental studies were performed with light sensitometry of which the measurement points were 21, 11 and 7. Then, it was applied to X-ray sensitometry and the inverse square law. The results are as follows. 1. 10-th Fourier homonics showed good adaptation to the X-ray film characteristic curve with 21-points, 8-th with 11-points, 7-th with 7-points. 2. The Fourier method was superior to the other methods for coefficient of correlation, standard deviation and residual sum of squares. 3. At the average gradient, there was no change in the variance of the number of measurement points. 4. Calculation time of this method was 9-sec at 21-points, 10-th Fourier homonics. 5. The Fourier method was useful for daily sensitometry.
This paper describes an scanning technique for synchronization with respiration. We have these problem that are moving artifact for peridiaphragmatic mobile (a baby, a patiant can not stop a breath) during CT examinations. Therefore, the authors have developed two scan techniques for synchronization with respiration (one is synchronization with rest expiratory, the other is synchronization with voice.) that are capable of solving these problems.
For an image intensifier (hereafter I.I.) , one key component of cineangiographic system, further grading up of its image (especially, the improvement of image noise characteristics) is requested recently. Now, a I.I., whose image noise and spatial frequency (MTF) characteristics are improved by an improved input phosphor screen, has been newly developed (hereafter a Super Metal I.I.). We assembled this type of I.I. into a cine fluorographic apparatus, evaluated and investigated its clinical usefulness.
As for Dual Energy Scan by the Rapid kV Switching method (RKS method), there is no influence of movement in comparison with the conventional 2-scan method. Also, various processing of the high reliability that was not obtained when the post-reconstruction method is used, because it is using the pre-reconstruction method when dual processing is produced. There is a Monoenergetic Image (MEI) as one of those processings. It is one of the simulated images that is made by using a single X-ray spectrum. To improve the accuracy of the CT-value by the thing that it decreases beam-hardening effect can. Also, it consists of one means clarifying the constitution substance of a photographic subject. Thereupon, we carried out a basic evalution, by using a phantom.
To improve image quality by removing scattered radiation more perfectly, various anti-scatter devices have been designed and reported. With conventional Bucky's device, when grid's transmission of primary radiation is large and its transmission of scattered radiation is little, we can expect considerable improvement of image quality. A high ratio grid with wood spacer satisfy these conditions. In our hospital, we have changed grid ratio of Bucky's device to 16:1 instead of 10:1, thus enabling a high quality image with little exposure.
It is necessary that radiographing during operation is carried out speedily with high accuracy. Also, it is important that the image produced can provide a doctor with highly valuable diagnostic information. Until now, we have radiographed patients by inserting a conventional cassette together with a staitionary grid into a narrow space in the operation table, or directly into the back of the patient. For this reason, it has often been necessary to re-radiograph the patient due to accidental slippage of the staitionary grid. Also, since it has been difficult to put the cassette in the proper position, there was great difficalty in handling them. At the same, there have been various problems in the radiographic images. We have devised and manufactured a stationary grid-combined cassette which is suitably adaptable to operation tables, measured and compared the sharpness and graininess of radiographic images obtained by use of a conventional cassette and a stationary grid-combined cassette, respectively, together with the use of Konica Intensifying Screens and Konica New A film.