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According to the World Health Organization (WHO), roentgenographic examinations constitute the major part of medical X-ray examinations. A roentgenographic apparatus should meet the following requirements: 1) high quality of imaging; 2) possibility of X-raying in main X-ray projections; 3) safety of patients and medical personnel; 4) easy installation and maintenance; 5) easy use; 6) possibility of working with autonomous power supply. The apparatus should implement functions of X-ray table and X-ray support and have three workplaces. According to WHO, apparatuses meeting these requirements are used to perform up to 50% of all X-ray examinations. Apparatuses of this type for film roentgenography are available from many manufacturers [2]. The same requirements can be extended to digital roentgenographic apparatuses, such as the ARTs-01-OKO digital roentgenographic apparatus available from Electron Scientific-Manufacturing Association (Fig. 1).The ARTs-01-OKO digital X-ray apparatus is used for roentgenographic examinations of a patient in standing, sitting, or supine positions. It provides Xraying in more than 100 standard projections of various organs and systems of the human body. A functional diagram of the apparatus is shown in Fig. 2.The X-ray power supply (XRPS) of the apparatus is based on inverter technology with power-line frequency conversion to kilohertz range. Voltage pulsations do not exceed 5%. The power supply allows varying the anode voltage within a range of 40 to 145 kV with a step of 1 kV. The quantity of electricity can be varied discretely within the range of 0.2 to 640 mAsec (34 steps).The X-ray source has a bifocal X-ray tube with focal spot sizes of 0.6 and 1.2 mm and a maximal voltage of 150 kV. The variable aperture diaphragm of the X-ray source has a disk with filters. Use of a high-power mid-range power supply and an X-ray source

Roentgen's discovery of X-rays in 1895 gave rise to the development of systems for imaging of internal structures of the human body. This provided a new basis for medical diagnosis. In spite of harmful biological effects of X-rays and the appearance of less invasive methods of imaging, X-ray still remains the most widely used diagnostic method. The reason is that X-ray diagnosis is highly informative, and X-ray imaging equipment is being constantly upgraded to provide higher image quality.Until X-ray image intensifiers (XII) were developed, X-ray images were either directly viewed on a fluorescent screen or detected with special X-ray films. The method of imaging based on a fluorescent screen has many disadvantages. Because of the detrimental effect of X-ray radiation, dose power in the plane of the screen exceeding 200 i.tR/sec cannot be permitted. The brightness of the screen at such doses is less than 3.10 -3 cd/m 2, so the image is seen with twilight vision and fine details and contrast differences are difficult to discern. A physician cannot extract all information contained in such images because of the limitations of human vision. To solve this problem, the brightness of the image should be intensified to at least 100 cd/m 2. Before XII were developed, high-quality X-ray images for diagnosis were only obtained using X-ray films. At that time, general roentgenoscopy had a limited area of application, mainly for functional examinations and for determining areas of interest for subsequent local roentgenography.Development of XIIs in the 1950s gave rise to the introduction of X-ray television systems into medical practice. These systems have revolutionized X-ray diagnosis, especially in roentgenology departments where XIIs replaced X-ray screens.X-Ray image intensifiers are now an indispensable part of the equipment of X-ray diagnostic departments worldwide. The increased brightness provided by XIIs increases the amount of information obtained during an X-ray examination to be increased severalfold, whereas the required dose power is decrease 3-5 times less than by imaging using an X-ray screen. Also, it is not necessary to observe modern X-ray images in full darkness; only partial dimming of lights is required. Images on a monitor screen can be observed by a group of roentgenologists; this facilitates training of students and junior physicians in X-ray diagnosis.The use of modern digital television technologies provides new advantages of X-ray image intensifiers. Digital processing of images is now possible; this can be used to eliminate interfering parts and to improve sharpness and contrast of an X-ray image. It is also possible to perform local digital roentgenography. In modern industrially developed countries, local digital roentgenography is gradually replacing conventional film roentgenography. This is due to a number of advantages of local digital roentgenography.Digital roentgenography provides high-quality X-ray photographs in real time. The radiation load on the patient is reduced. Digital roentgen...