[A realistic approach to the modelling of nonuniform whole-body radiation exposures in a radiobiology experiment].

The equidosimetric principle for modelling of general nonuniform radiation effects has been formulated. The method for realistic modelling of the effects by dynamic control of radiation exposure of two basic critical systems (active bone marrow and intestine) has been developed.

[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.

[Phantom research in the individual dosimetric planning of the intracavity irradiation of uterine cancer patients].

The paper is concerned with the results of dose measurements on a uterine phantom under the conditions close to those of the practice of radiotherapy of endometrial cancer patients using the AGAT-B unit. Comparison of experimental and rated dose values made it possible to find points of particular clinical alertness as well as a point of the control of accuracy of dose formation during a radiotherapeutic session.

[Individualization of the dosimetric requirements of intracavitary irradiation in the radiotherapy of gynecologic patients].

The authors proposed a method of dosimetric planning in intracavitary irradiation taking into account the individual features of a patient, including the status of the uterus during the introduction of radiation sources into its cavity. To simulate the dynamics of a resultant uterus shift a special device was developed to obtain information required for individual planning. The proposed method is aimed at the prevention of undesirable radiation reactions and complications in healthy organs.

Calculation of the estimated collective effective dose equivalent (SE) due to x-ray diagnostic examinations--estimate of the SE in Finland.

The collective effective dose equivalent caused by diagnostic x-ray examinations in Finland has been estimated. The influence of how the remaining organs are selected, as specified by the International Commission on Radiological Protection (ICRP), on the effective dose equivalent, HE, has been studied. The doses to 23 different organs, including the six primary organs and 17 relevant remaining organs, were calculated.

[Dosimetric basis for joining large fields of complex configuration during total irradiation of the lymphatic collecting vessels].

The paper is concerned with the results of experimental dosimetric studies on an anthropomorphic phantom using thermoluminescent dosimetry at the site of the joining of large fields of complex shape simulating total irradiation of the lymphatic collectors. The studies demonstrated the appropriateness of the joining at a distance of 1 cm between the fields. In such a variant adequate irradiation of the lymphatic system was achieved whereas an increase in a distance between the fields resulted in a risk of recurrence in under-irradiated areas without a significant decrease in radiation dose exposure to healthy organs and tissues.

[Effect of x-ray spectrum transformation on bone marrow dose].

A study was made of change of the spectrum (spectral transformation) of x-ray radiation while passing through the soft tissue. Thirty-two depth spectra computed by the Monte-Carlo method and 16 experimentally measured spectra including 9 depth spectra taken from literature, were analysed. A method of the calculation of an absorbed dose in the red bone marrow with account of spectral transformation was described.

[Computational methods for determining the mean tissue doses during x-ray procedures].

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.

[Basis for allowable errors in determining doses to patients during roentgenologic examinations].

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.