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[Radiation safety in space flights in the Intercosmos program].

This paper reviews the basic stages in the development of radiation safety of space flights within the framework of the Intercosmos program, including ground-based experiments on charged particle accelerators and gamma-emitters and actual flight studies onboard biosatellites and orbital stations. The paper also discusses norms and standards of radiation safety as related to flights of varying duration. It emphasizes the contribution made by Intercosmos cooperative projects into the development of space flight radiation safety parameters adopted as standards by the USSR Standardization Committee.

Humans↗
PubMed1988

The effect of accelerated argon ions on the retina.

It has been postulated that high energy heavy ions cause a unique form of damage in living tissue, which results from the high linear energy transfer of accelerated single particles. We have searched for these single-particle effects, so-called "microlesions," in composite electron micrographs of retinas of rats which had been irradiated with a dose of 1 Gy of 570 MeV/amu argon ions. The calculated rate of energy deposition of the radiation in the retina was about 100 keV/micron and the influence was four particles per 100 micron 2. Different areas of the irradiated retinas which combined would have been expected to be traversed by approximately 2400 particles were examined. We were unable to detect ultrastructural changes in the irradiated retinas distinct from those of controls. The spatial cellular densities of pigment epithelial and photoreceptor cells remained within the normal range when examined at 24 h and at 6 months after irradiation. These findings suggest that the retina is relatively resistant to heavy-ion irradiation and that under the experimental conditions the passage of high energy argon ions does not cause retinal microlesions that can be detected by ultrastructural analysis.

Animals↗
PubMed1987

[Peroperative radiotherapy in cancer of the pancreas].

7 patients presenting with unresected (6 cases) or resected (1 case) cancer of the pancreas were treated peroperatively by radiotherapy. Tumors were treated with 15 to 20 Gy delivered by a particle accelerator. There were no post-operative complications. Three patients who were experiencing pain before radiotherapy no longer had pain after radiotherapy and this effect was maintained. Five patients died during the follow-up period after 5 to 10 months. Two patients are still alive after 4 and 9 months' follow-up. This experience with peroperative radiotherapy should be continued.

Aged↗
PubMed1991

Transient expression of beta-glucuronidase in Arabidopsis thaliana leaves and roots and Brassica napus stems using a pneumatic particle gun.

Successful transient expression of beta-glucuronidase (GUS) in Arabidopsis thaliana leaves and roots and Brassica napus stems was obtained after gene delivery with a pneumatic particle gun driven by compressed air. Effects of the pneumatic pressure used to accelerate the particles (accelerating pressure; 85 to 200 kg/cm2) and of preculture periods of plant tissues (0 to 6 days) on the efficiency of gene delivery were studied. In A. thaliana leaves, best results were obtained at 115 kg/cm2 of accelerating pressure and 3 days of preculture. In A. thaliana roots, the optimum was at 200 kg/cm2 of accelerating pressure and 3 days of preculture. These results indicate that both preculture period and accelerating pressure are vital factors that determine the efficiency of gene delivery by particle gun.

Atmospheric Pressure↗
PubMed1978

[Medical applications of cyclotrons (author's transl)].

Isochronous cyclotrons used to accelerate different charge particles (protons, deuterons, alphas...) at variable energies, have important medical applications, for neutron teletherapy, in vivo or in vitro activation analysis or production of short-lived radioisotopes for nuclear medicine. The characteristics of the cyclotron presently available are described for these three applications (low energy "compact" cyclotrons, cyclotrons of intermediate and high energies), and their advantages are discussed from the points of view of the medical requirements, the financial investments and the results obtained.

Activation Analysis↗
PubMed1986

Early alveolar clearance of particles in rabbits undergoing acute and subchronic exposure to ozone.

The concentration-response relationship for changes in early alveolar clearance resulting from O3 inhalation were investigated. Groups of five rabbits were exposed to 0.0, 0.1, 0.6, or 1.2 ppm O3, 2 hr/day X 1 day; or to 0.0, 0.1, or 0.6 ppm O3, 2 hr/day X 13 days. Following the initial O3 exposure all rabbits inhaled an aerosol of 85Sr-tagged, 3.0-micron, polystyrene latex particles and particle retention was determined daily for the following 14 days. Single exposures to O3 produced a concentration related trend from accelerated clearance at 0.1 ppm to a transient impairment of clearance at 1.2 ppm. Subchronic exposure resulted in a significant acceleration of particle clearance at both 0.1 and 0.6 ppm, with the effect more pronounced at the higher level. These results demonstrate that single or repeated exposure of rabbits to 0.1 ppm O3, a level below the current National Ambient Air Quality Standard, produces alterations in early alveolar clearance. The effects observed at higher levels of O3 appeared to depend on both the concentration and exposure regime; acute exposures produced a concentration related trend toward an initial retardation of clearance, which was followed by an acceleration in particle removal, while repeated exposures resulted in a persistent acceleration of clearance.

Animals↗
PubMed1976

Morphologic and morphometric analysis of the early effects of x-ray and heavy-ion irradiation of hamster lung.

Morphometric methods were to used to compare the early effects of graded single doses of x-rays with accelerated heavy particle (helium or neon) irradiation of hamster lung. Increased values in the volume densities of both capillary lumina and inflammatory cells at 2 weeks postirradiation were observed. Neon-ion irradiation wes statisically different from x-irradiation at all dose levels, while helium-ion irradiation showed significant increases only at higher doses (1000 to 1500 rads). At 1 month post-irradiation, the volume densities of capillary lumina after heavy particle irradiation began to return to control values, while those in x=irradiated lungs continued to be elevated. The volume density of inflammatory cells remained increased for all types of irradiation, and the highest values were obtained in neon-ion irradiated lungs. Accelerated heavy particle irradiation would therefore appear to elicit a more intense early radiation than does x-irradiation but the chronic significance of these findings is not yet known.

Animals↗
PubMed1979

[Possibilities of variation in skip pendulum irradiation (author's transl)].

Irradiation techniques should be judged not by dose distribution only but also by the effort necessary for their realization. Skip pendulum irradiation is a technique excelling not only through suitable dose distribution but through effortless adjustment as well. The possibilities of variation in skip pendulum irradiation are examined, a schedule facilitates the choice of field breadth and pendulum angle. Skip pendulum irradiation should gain importance, too, for the bremsstrahlung from a linear accelerator.

Humans↗
PubMed1989

Locus specificity for mutation induction in human cells exposed to accelerated heavy ions.

The relative efficiencies of two types of densely ionizing particles were compared for the induction of mutations at two distinct genetic loci in human cells. Mutations to 6-thioguanine resistance (hgprt locus) or to trifluorothymidine resistance (tk) locus were scored in TK6 human lymphoblastoid cells exposed to graded doses of 40Ar ions (470 MeV/amu, LET = 95-97 keV/microns) or 28Si ions (456 MeV/amu, 61 keV/microns). The autosomal tk locus was more efficiently mutated than the X-linked hgprt locus following heavy particle irradiations. This was predominantly due to the contribution of a class of slowly growing mutants scored at the tk locus. Silicon ions were more efficient per unit dose than argon ions for the induction of mutants at either locus. When the mutant yield for a particular ion was compared with particle fluence, similar numbers of hgprt mutants are induced by equal numbers of 40Ar or 28Si ions. Comparison of the number of tk mutants with particle fluence demonstrates an increased efficiency for 28Si ions over 40Ar. These data suggest that the LET-RBE relationship may be different for individual genetic loci in human cells.

Argon↗