Performance of two commercial electron beam algorithms over regions close to the lung-mediastinum interface, against Monte Carlo simulation and point dosimetry in virtual and anthropomorphic phantoms.

Electron radiotherapy is applied to treat the chest wall close to the mediastinum. The performance of the GGPB and eMC algorithms implemented in the Varian Eclipse treatment planning system (TPS) was studied in this region for 9 and 16 MeV beams, against Monte Carlo (MC) simulations, point dosimetry in a water phantom and dose distributions calculated in virtual phantoms. For the 16 MeV beam, the accuracy of these algorithms was also compared over the lung-mediastinum interface region of an anthropomorphic phantom, against MC calculations and thermoluminescence dosimetry (TLD). In the phantom with a lung-equivalent slab the results were generally congruent, the eMC results for the 9 MeV beam slightly overestimating the lung dose, and the GGPB results for the 16 MeV beam underestimating the lung dose. Over the lung-mediastinum interface, for 9 and 16 MeV beams, the GGPB code underestimated the lung dose and overestimated the dose in water close to the lung, compared to the congruent eMC and MC results. In the anthropomorphic phantom, results of TLD measurements and MC and eMC calculations agreed, while the GGPB code underestimated the lung dose. Good agreement between TLD measurements and MC calculations attests to the accuracy of "full" MC simulations as a reference for benchmarking TPS codes. Application of the GGPB code in chest wall radiotherapy may result in significant underestimation of the lung dose and overestimation of dose to the mediastinum, affecting plan optimization over volumes close to the lung-mediastinum interface, such as the lung or heart.

[Altered states of consciousness].

The review of modern ideas concerning the altered states of consciousness is presented in this article. Various methods of entry into the altered states of consciousness are looked over. It is shown that the altered states of consciousness are insufficiently known, but important aspects of human being existence. The role of investigation of the altered states of consciousness for the creation of integrative scientific conception base is discussed.

Validation of a radiotherapy treatment planning system using an anthropomorphic phantom and MTS-N thermoluminescent detectors.

A treatment planning system (TPS) was validated in conditions of simulated radiotherapy (RT) of an anthropomorphic tissue-equivalent phantom. Individually calibrated solid MTS-N (LiF:Mg,Ti) detectors were placed within the treatment volume in this phantom which was then repeatedly irradiated by external 60Co or 6 MV X ray beams. On the basis of TLD-measured depth-dose curves for the two beams, the relative accuracy of determining dose (of the order of 1 Gy) at live depths in a water phantom is about 0.4-0.6%. In the volume of interest representing the target volume, the relative standard difference between the calculated and measured dose values ranged between 1.3% and 2.2% for the 60Co and 6 MV X ray beams, respectively. The TPS-calculated uniformity of irradiation of that volume is within 1%. While fraction-to-fraction repeatability was within 1-2%, systematic underexposure around the reference point, by 2-3%, was found in two consecutive exposures by sets of both beams.

[The physiological effects of the voluntary control of respiration in children and adolescents]. / Fiziologicheskie éffekty proizvol'nogo upravleniia dykhaniem u detei i podrostkov.

The information about the peculiarities of the forming the voluntary control of respiration in age aspects is produced in this article. It is shown, that the respiratory tests: voluntary hyperventilation and voluntary breath holding may be the convenient model for researching this problem. The irregular in the ontogenesis forming of the reactions of main physiological systems of the organism on the voluntary hyperventilation is revealed. The phase analysis of the duration of voluntary breath holding showed, that the volitional control of respiration begins to realize at 12 years old. The dynamics of the indexes of cardio-vascular system and CNS indicates of the high reactivity of vegetative nervous system of adolescents and of more distinct alterations in functional state of CNS in children in comparison with adults during voluntary breath holding. The sex distinctions in the mechanism of synchronization the internal rhythmic processes during the voluntary breath holding, especially in adolescents are revealed.

[Extramedullary plasmacytoma of the maxilla]. / Pozaszpikowy guz plazmatyczno-komórkowy szczeki.

A rare case of extramedullary plasmacytoma in a 71 year old patient is reported. A classification of plasma-cell tumors is given, and differences in the course of the disease, prognosis, and response to treatment between various types of plasma-cell tumors are discussed.

[The participation of the respiration in the rhythmic interactions in the body]. / Uchastie dykhaniia v ritmicheskikh vzaimodeistviiakh v organizme.

The review of the modern notions about the rhythmic interaction of the respiration, cardiovascular system and CNS is produced in this article. The own data of the authors dedicated to individual, sex and age manifestations of this interaction during the voluntary control of respiration are used. The possible mechanisms of the connection of respiratory rhythms with rhythmic processes of cardiovascular system and CNS are discussed.

[The individual manifestations of respiratory rhythms]. / Indivudual'nye proiavleniia dykhatel'noi ritmiki.

The information about the individual peculiarities of the respiratory rhythmics of health people is produced in this article. It is shown, that the functional tests: voluntary hyperventilation, hypoxic hypoxia, their combined influence and natural sleep in normal and hypoxic conditions may be the convenient models for researching this problem. The dependence of the respiratory responses on the individual type of respiration in normal conditions is revealed. The authors concluded that not only the character of normal breathing but also the reactions on functional tests should be taken into account during the prognosis of alterations of the respiratory rhythmics in various conditions.

[The problem of adaptation to space flight]. / Problema adaptatsii k kosmicheskomu poletu.

The presented paper is the review of the theoretical aspects of adaptation as applied to the factors of space flight. The aspects which are used in the professional selection and in the training of cosmonauts are discussed. The theoretical basis of the methods for diagnostics of functional states of the body and for increase of the reserve abilities of cosmonauts is studied. The authors suggest the working of the problem of adaptation to more complicated space flights including interplanetary travels is in sight. The authors conclude that at the present creation of the general conception of adaptation to space flight as to the complex of extreme factors is necessary.

[The voluntary control of breathing under high-altitude hypoxia]. / O proizvol'nom upravlenii dykhaniem v usloviiakh vysotnoi gipoksii.

The effect of voluntary breathing (hyperventilation or breath holding) on the cardio-vascular system and the CNS in hypoxic conditions revealed a phasic dynamics of adaptation to hypoxia and intensification of cardio-vascular function on 6000 m. The mechanisms of the responses are discussed.