From Big Medical Encyclopedia

BREMSSTRAHLUNG — the short-wave electromagnetic radiation arising at change of the speed (braking) of charged particles electrostatic field of an atomic nucleus. Examples of T. and. can serve x-ray emission (cm.). magnetobrake, pl sinkhrotropny, the radiation arising at change of speed or it is bent trajectories of the movement of charged particles in magnetic field of the synchrotron. T. and. it is used practically in all fields of science and technology, including in biology and medicine (see the X-ray analysis, Rentge and about it but with Ik's t, Re of N tgenospek-traljn y became from, Rentgepostruk-tu r and y y and and is scarlet and h).

Intensity of T. and. it is inversely proportional to a square of mass of charged particle and is directly proportional to a square of atomic number of substance, in the field to-rogo props x odes of Friday of t about rm about! i iye z and rya in ykh particles. Therefore for gain in yield of photons, i.e. intensity of T. and., use rather light charged particles (more often electrons) and substances with big atomic number (e.g., molybdenum, tungsten, platinum). Besides, intensity of T. and. cos 2 0 is proportional. where 0 — a corner between the direction of the movement of a photon and speed of primary charged particle. At big energy of particles the sharp orientation of T appears. and. and practically all radiation energy is concentrated in a narrow cone of beams in the direction of the movement of a particle. This orientation of T. and. it is used for receiving intensive bunches of photons of high energy by means of accelerators.

A range Other continuous with the maximum energy of photons, an equal motive energy of the braked particles. For receiving T. and. use x-ray ap p arata (see) and particle accelerators (see).

T. and., received by means of X-ray apparatus, the kilo-electron-volt has effective energy from units to hundreds. With increase in energy of loaded spoke rapidly, the power of T. and. increases, reaching at the dynamitron with energy 70 Mei the size about 70% of the brought electric power.

In medicine of T. and. it is used for diagnosis and radiation therapy. For diagnosis (see) use X-ray diagnostic devices with effective energy of photons to 100 — 120 kev.

For radiation therapy (see) apply therapeutic X-ray apparatus (see. X-ray apparatus), linear particle accelerators (see), betatrons and microtrons with energy of photons to 25 Mei. High intensity of T. and. and good spacing of an absorbed energy is created by premises for their successful use at radiation therapy deeply of races-p about l about wives of N y x about and at x about l to it.

Safety of work with T. and. the dignity is provided with observance of rules of work according to requirements. legislations (see. Radiation safety).

Bibliography: Radiation therapy by means of an energetic rays, under the editorship of G. A. Zedgenidze, M., 1964; T yu and and -

N and M., etc. Physical bases of radiation therapy and radiobiology, the lane with fr., M., 1969; A n g e r s t e i n W. Grundlagen der Strahlenphysik und radio-logischen Technik in der Medizin, Lpz., 1975; D e e i e y T h. J. Principles of radiation therapy, L. and. lake, 1976.

A. N. Krongauz.