The Role of Radiobiology and Nuclear Medicine in Protection from the Effects of Ionizing Radiation (Domestic Experience).

This article presents the domestic experience in nuclear medicine, radiobiology, radiotoxicology, radiation protection, and health maintenance of nuclear industry workers and residents of the region of location of radiation hazardous facilities of the Russian Federation. In addition, the authors address the history and stages in the establishment of nuclear medicine and radiobiology in Russia, as well as modern projects and the prospects of further development of healthcare provision for workers in the nuclear industry.

[Early medical consequences of the radiation accidents in the former USSR Territory].

The paper sums up the information on radiation incidents at the former USSR territory, which incidents are related to the human exposure of clinically significant effects. Within more than 60 years (since 1949), at least 356 radiation incidents accompanied by the clinically significant human exposure have happened at the former USSR territory, which has resulted to clinically significant health effects in 765 victims. This exposed cohort includes 348 acute radiation sickness (ARS) patients including cases aggravated by local radiation injuries (LRI). 407 victims were affected by local radiation injuries only. Totally, 71 radiation induced fatalities were observed within first 3-4 months after the irradiation. The maximum adverse effects as a result of accidental exposure of radiation incidents in the former USSR territory, had a place for professional workers whose work is associated with sources of ionizing

[Study of effectiveness of long-term per oral and parenteral cincacine administration at parenteral 241Am incorporation into the organism].

Effect of long-term (during 4 weeks) cincacine administration following single parenteral 241Am intake has been studied on rats depending on method (per oral or parenteral), dosage and time of treatment initiation. Cincacine administration leads to limitation of radionuclide incorporation in the major organs of deposition for the both methods of introduction. At the parenteral 241Am intake in the organism parenteral cincacine administration was found to be more effective compared to per oral cincacine administration even in case of its dose increase by a factor of 6 and 12. At the parenteral introduction of the preparation, time of treatment beginning is more significant than at per oral administration.

[Medical-prophylactic properties of the low-molecular-weight chitosan at environmental radiation injury]. / Lechebno-profilakticheskie svoistva nizkomolekuliarnogo khitozana pri éksperimental'nom luchevom porazhenii.

The possibility of the successful modification of radiation injury by chitosan with low molecular weight (10 kDa) has been established under experimental conditions. The survival of mice increased up to 72.7 and 44.7% respectively at intravenous and intramuscular injection 30 min before gamma-irradiation with a dose 8 Gy (LD97). In guinea pigs the effect was 50-52.6% at intravenous and 40% at intramuscular administration 1-3 h after irradiation with a dose 5 Gy (LD90). Radioprotective efficiency of 10 kDa chitosan is close to that of high-molecular-weight (65-70 kDa) preceding (medicine RS-10 and RS-11).

[Dependence of radioprotective activity of chitosan on its molecular mass]. / Izuchenie zavisimosti radiozashchitnoi aktivnosti khitozana ot ego molekuliarnoi massy.

The influence of chitosan molecular mass (70, 10 and 5 kDa) on its radioprotective efficiency in mice experiments was studied. It was shown that chitosans with molecular masses of 70 and 10 kDa had similar radioprotective properties. The survival of mice increased up to 73% and 87% respectively at intravenous injection 15-30 min before a whole-body exposure to 137Cs gamma-radiation at a dose of 8 Gy (Cd97/30). Practically absolute loss of radioprotective activity occurred below a threshold of about 10 kDa. The results showed a high chitosan radioprotective activity in a wider range of molecular masses than it was supposed earlier.

[Potency of peroral and parenteral administration of Zinc-DTPA for decorporation of 241Am from the gastrointestinal tract]. / Effektivnost' tsinkatsina pri peroral'nom i parenteral'nom putiakh vvedeniia v dekorporatsii 241Am, postupivshego v pishchevaritel'nyi tract.

An effect of cincacine at three doses (25, 150 and 300 mumol/kg) has been studied in rats receiving 241Am citrate intragastrically. The radionuclide was introduced every other day for 2 weeks. The total content was 925 kBq/kg. A cincacine administration leads to limitation of radionuclide accumulation in the major organs of deposition independent of the modes of intake. At gastrointestinal 241Am intake peroral cincacine administration is more effective in limiting this radionuclide accumulation in skeleton but less effective in reduction of its accumulation in liver compared to parenteral cincacine. No reliable dependence of cincacine efficacy on dosage has been revealed. A morphology study of organs has shown that cincacine ingestion at a dose of 150 mumol/kg for 4 weeks and at a dose of 300 mumol/kg for 2 weeks produces a toxic effect on the small intestine mucosa. 25 mumol/kg is the optimum dose and per os administration of higher doses is not expedient.

[Investigation of biologically active supplement Marinid as a prophylactic agent in ecologically unfavorable territory]. / Issledovanie biologicheski aktivnoi dobavki marinid v kachestve profilakticheskogo sredstva dlia ékologicheski neblagopoluchnykh territorii.

Physicochemical investigation of the biologically active supplement Marinid has been carried out. Biological accessibility of iodine containing in Marinid has been determined. About 60 micrograms of iodine can be assimilated by thyroid from one 0.5 g Marinid tablet. Daily iodine need for groups of different age can be satisfied by 1-4 tablets. Marinid reduces 90Sr resorption from gastrointestinal tract by 20-40%.

[Study of the influence of peroral zincacin on the removing of ingested Americium]. / Issledovanie vliianiia peroral'nogo primeneniia tsinkatsina na vyvedenie ameritsiia pri ego postuplenii v zheludochno-kishechnyi trakt.

Effect of different cincacine doses was studied in rats ingesting americium citrate during 2 weeks. As a result new data showing the possibility and efficacy of per oral cincacine administration at americium intake into digestive tract have been obtained. Dose dependence of cincacine efficacy has been stated for per oral 241Am intake. Preparation administration at a dose of 25 mumol/kg reduces amount of 241Am in skeleton, liver and kidney by 93, 90 and 33%, respectively and is optimum for radionuclide removal from the body and for the prevention of its deposition in organs. Digestive system organs and kidney structure at cincacine administration at a dose of 150 and 300 mumol/kg) to the rats ingesting 241Am have been studied.

[Study of 137Cs transfer to the rat offspring with breast milk and a modifying effect of ferrocene on this process]. / Issledovanie zakonomernostei perekhoda 137Cs v potomstvo krys s molokom materi i modifitsiruiushchee deistvie ferrotsina na étot protsess.

137Cs transfer to the lactating rats' offspring has been investigated following daily administration of the radionuclide to the females. Certain patterns have been established for 137Cs accumulation dynamics in the female rats and their progeny during 30 days of suckling. Radiocaesium accumulation multiplicity in both female rats and offspring, as well as absorbed dose formation and a modifying effect of ferrocinum on these processes have been studied.

[Study of 137Cs transfer across the placenta to the rat fetuses and effect of ferrocin on these processes]. / Issledovanie zakonomernostei perekhoda 137Cs cherez platsentu v plody beremennykh krys i vliianie ferrotsina na éti protsessy.

The 137Cs placental transfer to the fetuses was studied using a daily oral 137Cs administration to pregnant rats. At day 19 of gestation, the fetuses receive 0.8% of the amount administered to the female. A daily application of ferrocinum reduces the 137Cs content of the female body by 82-84% and decreases the fetal accumulation down to 0.14%.

[Reply to the letter-to-the-editors by V.A. Pitkevich, V.K. Ivanov, S.Iu. Chekin, A.F. Tsyb, "Concerning the problem of radiation exposure levels to the Chernobyl AES accident clean-up participants, included in Russian Medical-Dosimetric State Registry"]. / Otvet na pis'mo v Redaktsiiu V.A. Pitkevicha, V.K. Ivanova, S.Iu. Chekina, A.F. Tsyba "K voprosu o luchevykh nagruzkakh na uchastnikov likvidatsii posledstvii avarii na Chernobyl'skoi AES, zanesennykh v Rossiiskii gosudarstvennyi mediko-dozimetricheskii registr".

Theoretical and practical problems related to the dosimetric data verification for recovery workers at the Chernobyl NPP are considered. The distinctions in definitions epsilon-entropy in paper [1] and delta-entropy in [2] are considered. In a certain measure this distinctions explain distinction in conclusions, made in these papers. Method of dosimetric data collection, used by Institute of Biophysics and its difference from the method of data acquisition, used in national Medical-dosimetric registers is described. Results on determination of a share of participants given for various clean-up worker divisions, contained in pointed delta-shape peaks, received by two various methods, stated in [2] and [6], are compared and their satisfactory conformity with one another is established.

[The irradiation levels of the participants in the cleanup of the aftermath of the Chernobyl accident in 1986-1987 and the verification of the dosimetric data]. / Urovni oblucheniia uchastnikov likvidatsii posledstvii Chernobyl'skoi avarii v 1986--1987 gg. i verifikatsiia dozimetricheskikh dannykh.

It is considered the organization of individual dosimetric monitoring (IDM) within 30-km zone around Chernobyl nuclear power plant (CNPP) in 1986 for different contingents of recovery workers: the CNPP personnel, Management for Construction 605 (MC-605), military recovery workers, persons assigned to 30-km zone. It is concluded that the quality of IDM had decreased in the following series: the MC-605 personnel, the CNPP personnel, the assigned persons, and military units. The method of dosimetric data verification for recovery workers in 1986 is presented which is based on the analyses of the dependency H(delta)/In delta from delta, where delta is a step of the histogram of distribution, and H(delta) is delta-entropy of distribution. The results obtained by this method correspond to the results of the experts' estimation. It was shown that 60% of registered individual doses for the whole contingent of the recovery workers differ from the real exposure doses. Using the theory of hybrid lognormal distribution it was obtained, in our opinion, real external dose distribution for all the recovery workers. It was estimated that 7% of recovery workers received doses more than 0.25 Gy. Also, the data on values of mean and collective doses for different contingents, as well as for all persons involved in recovery operations is presented.

[Characteristics and results of the determination of the doses of internal irradiation of the thyroid gland in the population of contaminated districts of the Byelorussian Republic]. / Osobennosti i rezul'taty opredeleniia doz vnutrennego oblucheniia shchitovidnoi zhelezy dlia naseleniia zagriaznennykh raionov Respubliki Belarus'.

The authors provide the results of studying the reconstruction of individual doses of thyroid radiation among the community living in polluted areas of the Byelorussian Republic according to radiation monitoring data and with regard to the nature of radioactive pollution of the land. Every individual result of estimating the degree of thyroid radiation was characterized by 3 magnitudes: the lower and upper limit of possible values and by the intermediate (basic) value. The authors hold that studies of the correlations between the values of individual doses of thyroid radiation and different parameters of the radiation situation in every region will promote further specification of individual doses of thyroid radiation.

[Characterization of irradiation levels of the population in the controlled areas 4 years after the Chernobyl AES accident]. / Kharakteristika urovnei oblucheniia naseleniia kontroliruemykh raionov za 4 goda posle avarii na Chernobyl'skoi AES.

Based on a summary of the radiation and hygienic control data, the authors suggest empiric mathematic models depicting the dynamics of the formation of external and internal radiation doses within the first 4 years after the Chernobyl NPP accident. It has been established that in the areas of rigid control, the mean radiation dose amounted, within the period indicated, to 3.5 kev, that due to external radiation to 2.67 kev; the collective dose for 273,00 population living in those areas constituted 9.6 kev.

[The regulations of radiation exposure, radiation loads on the population and the medical consequences of the Chernobyl accident]. / Reglamenty radiatsionnogo vozdeistviia, luchevye nagruzki na naselenie i meditsinskie posledstviia Chernobyl'skoi avarii.

The paper is concerned with analysis of strategy of the regulation of radiation exposure of the population and the practical use of the levels of intervention in different phases after the Chernobyl accident. The author represents data on the levels of whole-body irradiation of the population in the areas under strict control, and dose exposure of the thyroid in children and adults. Mean individual and collective doses of whole-body irradiation over the period of 1986-1989 and predictable dose exposures were assessed. Some data on probable pathology of radiation genesis in the population in affect on 1990 were considered.