One of the important factors affecting radiographic image quality is the scattered radiation arising from the interaction of the photons with the object being radiographed. A large amount of scattered radiation results in the reduction of image contrast. In order to investigate the effects of scattered radiation, we have measured the angular dependence of the responses of the planar Ge detector for the obliquely incident photons.
Our investigation established that the aotive area of, a 6 mmφ×5mm deteotr is 3 mm in diameter and the available. incident angle is within 20°In this region, the measured spectra were successfuly corrected with the monoenergetic response functions calculated by using the Monte Carlo method for a pencil beam of photons impinged normally on the center of the planar Ge detector.
When a grid is used to avoid scatter, obliquely incident scatter is limited. When a grid of the ratio 5: 1 is used, the scatter of incident angle of more than 11°coming crossly to the leaves is removed. Even if the scatter of incident angle of more than 20°is removed by a suitable collimator pinhole, the diagnostic X-ray spectra made using a grid can be measured with a bit of error

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The inverse square law is considered to be valid in measuring characteristic curves virtually governed by this law. But this law is not perfectly applicable to the tube voltage range for conventional radiography. In inverse square law, x-ray intensity is proportional to 1/rm (r means source detector distance)and the value of m is usually 2.0. In the report, the value of m with the ionization chamber and the fluorescent detector is studied.
The value of m measured by the ionization chamber detector changes from 2.1 to 2.0 when the tube voltage alters from 60 kVp to 140 kVp. However, the value of m obtained by the fluorescent screen detector remains at 2.1 in the same tube voltage range

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MFIP is a high speed image processing system with time shared multiframe data bus architecture, consisting of large image memory, the image processor with specially designed hardware, and image input/output units. The data bus with 64 bit bus lines is time shared to four channels, which is capable of transferring image data (16 bits/pixel) at the rate of 40 MW/sec. In this paper, we describe system architecture of WFIP and represent some experimental results.

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We have developed a new type of video memory system by which the image of the traces of moving contrast medium is able to be recorded. This memory system is effective to improve the image quality of the X-ray TV system by reducing the X-ray quantum noise. Then we have applied this memory system to the digital subtraction angiography and evaluated its performance.

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