X Ray sources with focal spot size of less than 0.1 mm called microfocal X ray radiation sources (MXRS) are widely used in domestic medical practice of X ray diagnosis [6]. Efforts of domestic researchers are focused mainly on microfocal medical X ray diagnosis for injuries and diseases of the locomotor apparatus [3].It has been shown in recent years that microfocal medical X ray diagnosis in combination with digital tech nologies provides a promising approach to microsurgery of bone tissues [4]. As a result, microfocal medical X ray diagnostic apparatuses are widely used in dentistry, max illofacial surgery, rheumatology, traumatology, orthope dics, prosthetics, medical expertise, etc.In recent years MXRS models for voltages 50, 70, 100, 120, and 150 kV, and X ray diagnostic apparatuses on their basis have been developed and manufactured in Russia [7]. The power of such apparatuses is 10 30 W. The exposure dose of such apparatuses is low.Although microfocal roentgenography provides high quality X ray images, specific features noted above impose restriction on the use of MXRS [11].X Ray photography at enhanced anode voltage is an approach to elimination of the disadvantages of microfo cal medical X ray diagnostic apparatuses.It was shown in [6] that correlation between X ray radiation intensity, anode voltage, anode current, and dis tance to the point of measurement (focal distance) is described by the following semiempirical equation:where J is the X ray radiation intensity; k is a scaling fac tor; i A is the anode current; Z M is the atomic number of the target material; U is the anode voltage, n = 2 5 depending on thickness and density of object; R is the focal distance. It follows from Eq. (1) that X ray radiation intensity at invariable anode current can be increased by decreas ing focal distance. Normalized data on the dependence of X ray radiation intensity on anode voltage calculated from Eq. (1) are given in Tables 1 4. The data were normalized to radiation intensity J 0 at standard conditions of X raying [8]: anode voltage, 100 kV; anode current, 50 mA; focal distance, 1000 mm. The calculations were performed for two factors n and two focal distances R.This distance 300 mm was chosen for the following reasons. At focal spot size 0.1 mm allowable image blur of
