[Radiation characteristics of narrow photon beams].

The paper is concerned with an analysis of the radiation characteristics (depth doses, beam contours, radiation output) of several medical linear accelerators in the formation of high energy narrow beams (up to 2 x 2 cm). Experiments and computer-assisted numerical simulation have shown that the use of an additional collimator makes it possible to obtain characteristics of photon beam dose fields in biaxial rotation comparable to those in irradiation of small intracranial targets with proton beams at the energy of 1000 MeV.