[Results and future of the activities of the Department of Medical Radiation Physics of the Central Scientific Research Roentgenoradiology Institute of the USSR Ministry of Public Health]. / Itogi i perspektivy deiatel'nosti otdela meditsinskoi radiatsionnoi fiziki Tsentral'nogo nauchno-issledovatel'skogo rentgenoradiologicheskogo instituta Minzdrava SSSR.

The main directions of research activities, pursued in the Department of Medical Radiation Physics over 25 years, are reviewed. The staff-members have done a lot for the development of Soviet modern radiotherapeutic engineering (electron accelerators). They are devising a cyclotron complex for purely medical purposes. Investigations in fundamental dosimetry, software for radiation therapy, computer use in x-ray studies will permit research in the following directions: --physicotechnical aspects of medical use of cyclotrons; --automation of radiation therapy technology (including software and control systems); --procedures to ensure quality in radiation therapy; --dosimetric maintenance of radiobiological experiments; --computer use for analysis of medical images.

[Characteristics of diamond detectors of ionizing radiation]. / Kharakteristiki almaznykh detektorov ioniziruiushchikh izluchenii.

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]. / Izmerenie doznykh polei razlichnymi detektorami.

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]. / Radiatsionnye kharakteristiki uzkikh fotonnykh puchkov.

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.

[Computational methods for determining the mean tissue doses during x-ray procedures]. / Vychislitel'nye metody opredeleniia srednetkanevykh doz pri rentgenologicheskikh protsedurakh.

The Soviet and Finnish authors presented a short description of two computer methods to determine doses in the patients' organs. Based on the general principles, such as a semiempirical mathematical description of dose fields and a realistic anthropomorphous phantom, these methods differed significantly in the algorithms used and ways of solving specific problems. The comparison of these methods and calculated dose values with the results of experimental measurements on the phantom showed a good convergence of the results. The divergence of calculated and experimental data by the values of the mean absorbed doses in the organs did not exceed +/- 35%. The advantages and prospects of the use of the computer methods for the evaluation of doses received by patients, were demonstrated.

[Basis for allowable errors in determining doses to patients during roentgenologic examinations]. / Obosnovanie dopustimoi pogreshnosti opredeleniia dozovykh nagruzok na patsientov pri rentgenologicheskikh issledovaniiakh.

Basing on the utilization of the benefit-injury concept the authors put forward an approach to the substantiation of permissible errors in the values of the mean doses intended for the patient's critical organs in x-ray examination. It was shown that in the elaboration of methods to determine the mean tissue doses one should aim at reaching a mean quadratic error of +/- 30% in their values.

[Optimal conditions for the formation of a radiation beam in gamma-therapeutic equipment]. / Ob optimizatsii trakta formirovaniia rabochego puchka izlucheniia terapevticheskikh gamma-apparatov.

The symmetry and reproducibility of the radiation field in the gamma-therapeutic device should be considered in terms of the recommendations given in the IEC Publications for medical electron accelerators, since the requirements for the exposed dose are similar in both cases. The calculations of the relationship between the source volume luminosity and the dimensions of the collimator system have shown that the increase in the diameter of the shutter hole for the operating beam results in much lower requirements for the source-shutter alignment, and so asymmetry and instability of the radiation field are essentially excluded.

[Dosimetric characteristics of the bremsstrahlung beam from the LUE-15M medical linear electron accelerator]. / Dozimetricheskie kharakteristika puchka tormoznogo izlucheniia meditsinskogo lineinogo uskoritelia élektronov LUE-15M.

The paper presents methods and results of a study of radiation-physical characteristics of inhibitory radiation beam with the Grenz energy of 15MeV generated by an electron linear accelerator LUE-15M. Special emphasis is laid on primary dosimetric information used for the planning of radiotherapy: depth doses, beam profiles, dose functions of a collimated beam. It has been shown that in general the accelerator meets the requirements of the International Electrotechnical Commission. General error in the focal absorbed dose at the expense of variable parameters of the accelerator was evaluated. It does not exceed +/- 3.5%.

[Use of narrow photon beams to irradiate small intracranial targets]. / Ispol'zovanie uzkikh puchkov fotonov dlia oblucheniia malykh vnutricherepnykh mishenei.

Using a specially designed program, the authors managed to obtain dose distributions in irradiation by a rotation method in two planes of small intracranial targets with narrow photon beams (up to 1cm) with the energy of 0.2; 1.25; 15MeV. It has been shown that though these distributions less correspond to clinical requirements than those for proton beams the use of narrow photon beams seems promising in this field of radiology.

[Semi-automatic device for measuring relative distribution of doses of ionizing radiation]. / Poluavtomaticheskoe ustroistvo dlia izmereniia otnositel'nykh raspredelenii doz ioniziruiushchego izlucheniia.

During operation and adjustment of ionizing radiation sources it becomes necessary to determine relative distribution of the radiation doses. A semiautomatic device for taking and registering relative distribution of doses in any of the 3 aqueous phantom coordinates, based on an analogue recording of the 2 signals ratio on the self-recording potentiometer tape and upon synchronous movement of the transducer relative to the recording tape. A 0.05 cm3 ionization chamber was used as the transducer.