[Dosimetric planning of partial radiation exposure in radiobiological experiments].

The authors describe a new method of dosimetric design of partial radiation exposures (PRE) in radiobiological experiments on rodents, using a universal lead component screen. A choice of a shape of irradiation fields and location of screen elements on the body of an animal is done according to a CT program, developed in the IBM PC version. This method helps to standardize physicotechnical support of PRE in radiobiological experiments.

[Evaluation of the efficiency of the shaping of brehmstrahlung beams on electron accelerators].

Proceeding from analysis of the influence of parameters of the target-filter system on radiation-physical characteristics of braking radiation, some recommendations were issued for assessment of the efficacy of the forming systems of medical accelerators of electrons. A new criterion--a coefficient of the forming system efficacy--was introduced, characterizing a beam formation tract with relation to a whole set of radiotherapeutic problems.

[Characteristics of diamond detectors of ionizing radiation].

The article describes a device for detecting ionizing irradiation on the basis of a diamond detector and gives its characteristics. It has been shown that the diamond detector device by its parameters is superior to a similar device based on the silicon detector and in a number of cases to the ionizing chamber device. It can therefore be used successfully in the systems measuring the dose-radiation field.

[Measurement of dose fields using different detectors].

The authors presented and analyzed the results of measurement of dose fields of photon and electron radiation using 3 types of detectors (ionization camera, Si detector and diamond detector), alternately switched on to the CADSCAN dose field analyzer. The results of a study of dose fields of inhibitory radiation at 18 MeV were indicative of the similarity of data obtained with the help of diamond and Si detectors and an ionization camera. Comparison of the results for electron radiation at 4, 17 and 20 MeV showed that data obtained with the diamond detector, coincided with absorbed dose distributions calculated on the basis of ionization measurements whereas dose accumulation values obtained with the help of the Si detector were very high.

[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.