Irradiation dose for personnel during brachytherapy of malignant neoplasms with 32P microsources

Experimental measurements of the local absorbed radiation dose in the most irradiated parts of the bodies of personnel (the skin of the hands and palms, eyes, thorax, and abdomen of operators) by means of high sensitivity TLD-500K thermoluminescence detectors are reported. It is found that, for ³²P microsources with a total activity of 100 MBq, after 6 hours of work without protective x-ray gloves during a simulation of placing a real preparation in the region of the liver of an adult phantom, the maximum local irradiation dose to the hands (the skin of the left middle finger and thumb) from bremsstrahlung with deduction of the natural background and without special protective measures is 0.54 ± 0.001 mGy, the minimum dose (skin on the palm of the right hand) is 0.1 ± 0.01 mGy, and the irradiation of the thorax, abdomen, and eyes of the operator is less than 0.12 mGy. This presents no radiation hazard, even for repeated work with these sources. Translated from Atomnaya énergiya, Vol. 105, No. 4, pp. 233–235, October, 2008.     

Internal irradiation of the thyroid gland in residents of Kaluga Oblast from results of <Superscript>131</Superscript>I content measurements performed in May 1986

The content of ¹³¹I in the thyroid gland of approximately 30000 residents of Kaluga oblast was measured in May 1986. The work was supported by calibration and verification of the measurement means and procedure. The data making it possible to evaluate the individual, average, median, and collective dose of internal irradiation of the thyroid gland in people of different ages in the populated points of the oblast are presented. The irradiation dose to the thyroid gland in children is much higher than for adults. It is found that the individual dose of internal irradiation to the thyroid gland is described by a nearly log-normal distribution. Some of the individuals examined have an individual dose which is several-fold higher than the average and median dose. This indicates the presence of groups with an elevated radiation risk; attention should be focused on this group first when medical-prophylactic and protective measures are taken. The data from Kaluga oblast, combined with similar results from Bryansk oblast and Belarus, have served as basis for reconstructing the individual absorbed irradiation dose to the thyroid gland and as dosimetric support of radiation-epidemiological studies using the case-monitoring procedure. Translated from Atomnaya énergiya, Vol. 105, No. 2, pp. 97–103, August, 2008.     

低剂量α粒子辐照对斑马鱼胚胎初级造血分子标记物的影响

为探究低剂量α粒子辐照对斑马鱼初级造血的影响,使用241Am作为α粒子辐照源,对脱绒毛膜后的5 hpf胚胎进行0、0.425、0.85、1.7 mGy的辐照,采用整体原位杂交技术检测了约14 hpf斑马鱼胚胎初级造血分子标记物gata1a和spi1b的表达,采用实时荧光定量PCR技术检测了22 hpf斑马鱼胚胎初级造血分子标记物gata1a和spi1b的相对表达,并采用联大茴香胺染色法检测了48 hpf血红蛋白含量的变化。通过与对照组相比发现,0.425 mGy剂量组的gata1a表达无显著性差异（p>0.05）,spi1b表达略有减少（p<0.05）,血红蛋白含量显著减少;0.85 mGy剂量组的gata1a和spi1b表达均显著降低（p<0.01）,血红蛋白含量明显减少;1.7 mGy剂量组的gata1a和spi1b表达均显著升高（p<0.001）,血红蛋白含量显著增加。以上结果表明,剂量小于0.85 mGy的α粒子辐照对初级造血产生了抑制作用,而剂量为1.7 mGy的α粒子辐照诱导了胚胎兴奋效应,即剂量为1.7 mGy 的α粒子辐照对胚胎期斑马鱼初级造血具有促进作用。     

Analysis of the characteristics of <Superscript>238</Superscript>U, <Superscript>232</Superscript>Th, <Superscript>237</Superscript>Np,and <Superscript>231</Superscript>Pa radiators for fission ionization chambers for measuring the neutron flux density in the ITER diverter

Computational results, obtained by analyzing possible schemes of nuclear transformations of each of four threshold fission radiators ²³⁸U, ²³²Th, ²³⁷Np, and ²³¹Pa, for fission ionization chambers are presented. The influence of the nuclear reactions (n, ƒ), (n, γ), and (n, 2n) on the characteristics of fission ionization chambers is taken into account in the nuclear transformation schemes for all four radiators. The results are presented in the form of a dependence of the sensitivity of the fission ionization chambers on the neutron fluence in the range 10²¹–10²⁴ cm⁻². The effect of 0.2 and 1 g/cm² thick boron screens is examined. Translated from Atomnaya énergiya, Vol. 106, No. 1, pp. 42–47, January, 2009.     

Evaluation of the irradiation dose rate for marine biota in the region of the destroyed fukushima reactor (japan) in march–may 2011

The irradiation dose rate in March–May 2011 is evaluated for marine biota in the coastal zone near the destroyed Fukushima reactor and in the open sea. It is shown that for representative marine organisms (fish and mollusks) the irradiation dose rate did not exceed the safe level 0.4 mGy/h (10 mGy/day). In the open sea, 30 km from the nuclear power plant, the irradiation of marine biota is much lower than in the coastal zone near the nuclear power plant. A comparative evaluation is made of the irradiation dose rate for water organisms in the exclusion zones of the Eastern-Urals track of radioactivity and the Chernobyl and Fukushima nuclear power plants.     

<Superscript>59</Superscript>Ni Accumulation in Corrosion-Resistant Steel under the Action of Neutron Flux

A γ-ray line with energy E_γ = 11.3 MeV was detected during an experiment, performed on a nuclear reactor, investigating the characteristics of the energy spectrum of γ-rays. The most likely source of this line is radiative capture of thermal neutrons by ⁵⁹Ni nuclei, which accumulated in the corrosion-resistance steel as a result of the more than 20 years of irradiation in the reactor, via the reaction ⁵⁸Ni(n, γ)⁵⁹Ni. It was found that for thermal-neutron fluence 10²¹ cm⁻² the ⁵⁹Ni concentration is 0.47% of the ⁵⁸Ni concentration. __________ Translated from Atomnaya Energiya, Vol. 99, No. 4, pp. 268–272, October, 2005.     

<Superscript>63</Superscript>Ni-based β-electric current source

The possibility of developing a β-electric atomic battery with microwatt power based on ⁶³Ni with a lifetime of at least 30 years is analyzed. A method is proposed for large-scale commercial production of ⁶³Ni with concentration 80–90% in the final product. A design of a β-electric transducer based on macroporous silicon with optimized configuration and macropore depth (microchannels) is presented and analyzed. ⁶³Ni is deposited on the inner surface of the microchannels. A laboratory model of an atomic battery based on ⁶³Ni has been fabricated. The working parameters and the current-voltage characteristics of a 500 μW(e) atomic battery based ⁶³Ni (90% concentration) are presented. __________ Translated from Atomnaya énergiya, Vol. 103, No. 6, pp. 353–356, December, 2007.     

Determination of <Superscript>131</Superscript>I based dose equivalents for emissions of short-lived iodine isotopes

The coefficients required for evaluating the inhalation dose from short-live iodine isotopes entering the human body during a radiation accident associated with a spontaneous chain reaction are validated computationally. Such coefficients make it possible to reduce the effect of a collection of iodine isotopes to that of an equivalent amount of ¹³¹I. The dose inhalation load from an iodine emission aerosol cloud and the site contamination with ¹³¹I are evaluated for a spontaneous chain reaction in systems consisting of enriched metallic uranium with 10¹⁹ fissions with no localizing facilities present. __________ Translated from Atomnaya énergiya, Vol. 102, No. 5, pp. 311–315, May, 2007.     

Measurement of neutron capture and fission cross sections of <Superscript>236</Superscript>U

The cross sections for radiative capture and fission for ²³⁶U in the neutron energy ranges 1–2000 eV and 1–1000 eV, respectively, have been measured. The measurements were performed on a flight baseline 5.2 m of the FAKEL linear electron accelerator at the National Research Center Kurchatov Institute using a method based on measuring the distribution of the number of particles emitted by an excited nucleus with simultaneous measurement of the energy of each particle. The spectrum of the neutrons incident on a sample was measured by detecting the reaction ¹⁰B(n, α)⁷Li. The cross sections were normalized with respect to the resonance in ²³⁶U at 5.45 eV. The data obtained are compared with the results of other experiments and evaluated data.     

Content of cosmogenic <Superscript>7</Superscript>Be in the air layer at the ground at temperate latitudes

The ⁷Be content was measured in aerosols (once per week) and precipitation (once per month) was monitored as part of the monitoring of the radioactivity of the atmospheric layer near the ground in Rostov-on-Don in 2001–2005. Data were obtained on the correlations between the ⁷Be volume activity in aerosols and the Wolf number, temperature, and amount of precipitation. The highest correlation coefficients were observed during the spring (k = 1). It was determined that the volume activity of ⁷Be changes in the second half of the 23rd cycle of solar activity, i.e., the yearly average ⁷Be concentration increases toward the end of the cycle. Data were obtained on the seasonal dependence of the precipitation density and the volume activity of ⁷Be on the meteorological parameters (temperature, amount of precipitation). __________ Translated from Atomnaya énergiya, Vol. 102, No. 6, pp. 370–374, June, 2007.     

Dynamics of <Superscript>137</Superscript>Cs bottom contamination of the Tsimlyanskoe reservoir

Analysis of data obtained in 1990 and 2000 on the ¹³⁷Cs contamination of the bottom of the Tsimlyanskoe reservoir near the dam has revealed the salient variations of this contamination. The global fallout enters the water in the section near the dam from side tributaries and as a result of erosion from the closest water catchment areas. The fallout due to the accident at the Chernobyl nuclear power plant is added primarily with the solid runoff from the more highly contaminated catchment basins of the Don River. It is shown that shore abrasion, flows, and removal of sediment through the water outflow area influence the distribution of the ¹³⁷Cs content over the zones and the characteristics of the variation of this distribution in time. __________ Translated from Atomnaya énergiya, Vol. 103, No. 4, pp. 260–263, October, 2007.     

Calculation of the characteristics of the external irradiation of a human being as a result of <Superscript>137</Superscript>Cs contamination of soil

Monte Carlo estimates of the effect of certain characteristics of the external irradiation of a human being standing on the surface of soil contaminated with ¹³⁷Cs are presented. The spectrum and angular distribution of gamma rays in air and the effect of the height of the individual’s position above the soil surface, the area of the contaminated surface, the contamination depth in the soil, the snow cover, and the walls of a room are estimated. The effect of a change in certain computational parameters on the results is examined. It is shown that the density of the phantom material and soil have the strongest effect on the computational results. __________ Translated from Atomnaya énergiya, Vol. 104, No. 2, pp. 111–115, February, 2008.     

Fission vacuum chambers and secondary-emission detectors as effective tools for measuring the characteristics of <Emphasis Type="Italic">γ</Emphasis> and neutron radiation from intense sources

The results of measurements of the flux of fast neutrons in the density range 2·10⁸–2·10¹⁹ sec^–1·cm^–2 and γ-ray dose rate in the range 2·10^–3–1·10⁹ Gy/sec in different operating regimes of pulsed nuclear reactors and accelerators are presented. The parameters of the delayed photon radiation are presented.     

Use of γ Radiation from Short-Lived Fission Products for Detecting <Superscript>235</Superscript>U and <Superscript>239</Superscript>Pu

It is suggested that γ radiation with E _γ > 4900 keV from short-lived fission products produced by thermal neutrons be used to detect ²³⁵U and ²³⁹Pu in samples. A time regime is substantiated: 120 sec irradiation, 60 sec holding time, and 120 sec measurement time. The contribution of the reaction (n, p) on fast neutrons is studied.__________Translated from Atomnaya Energiya, Vol. 98, No. 5, pp. 365–370, May 2005.     

<Superscript>137</Superscript>Cs content and vertical migration in littoral soil of two lakes in Bryansk Oblast

The dynamics and present state of the radioactive contamination with ¹³⁷Cs of littoral soil of Lake Kozhanovskoe and Lake Svyatoe on the Besed’ River are presented. The parameters of the vertical migration of ¹³⁷Cs in soil-the rate of directional transfer with soil moisture, the diffusion coefficient, and the average velocity of vertical migration-are estimated by comparing the experimental and model distributions of ¹³⁷Cs content over soil depth. It is shown that at the present time the two 5-cm layer of soil can contain 20–90% ¹³⁷Cs depending on the type of soil and landscape. The average values of the diffusion coefficient, the rate of directional transfer, and the vertical migration velocity for 12-, 13-, and 20-year periods after the Chernobyl accident are 0.1–2.8 cm²/yr, 0.1–0.3 cm/yr, and 0.1–0.8 cm/yr, respectively. __________ Translated from Atomnaya énergiya, Vol. 102, No. 5, pp. 306–311, May, 2007.     

<Superscript>243</Superscript>Am neutron fission cross section and resonance parameters

The SVZ-100 lead moderation time neutron spectrometer at the Institute of Nuclear Physics of the Russian Academy of Sciences was used to measure the fission cross section for ²⁴³Am in the neutron energy range E_n = 0.3 eV – 10 keV. The resonance fission integrals and the area and fission width of the resolved resonances were calculated. The properties of the intermediate-structure resonances were evaluated. The results were compared with existing data and recommended evaluations.     

<Superscript>212</Superscript>Pb/<Superscript>212</Superscript>Bi Generator for nuclear medicine

A scheme for producing the α-emitters ²¹²Pb and ²¹²Bi, to be used in a promising method of diagnostics and therapy in oncology – radioimmunotherapy, is proposed. The technology is based on two generators operating in tandem: ²²⁸Th/²¹²Pb and ²¹²Pb/²¹²Bi. The first one is based on separation from an initial solution containing thorium isotopes and gaseous ²²⁰Rn, which secures the purity of the desired products ²¹²Pb and ²¹²Bi. For a ²²⁸Th/²¹²Pb model generator, the efficiency of ²²⁰Rn extraction from solution was ~60%. After conditioning, the ²¹²Pb solution from the ²²⁸Th/²¹²Pb generator was used to charge a column, which functioned as a ²¹²Pb/²¹²Bi generator, with a cation exchanger.     

Direct measurements of the<Superscript>90</Superscript>Sr activity in water using Cherenkov radiation

A computational-experimental investigation of Cherenkov radiation due to⁹⁰Sr−⁹⁰Y in water samples was performed. The Monte Carlo method was used to simulate the generation of photons from the decay of⁹⁰Sr−⁹⁰Y and other isotopes in water in the range 220–600 nm. The Cherenkov radiation was measured using a low-noise photomultiplier with a tellurium-rubidium photocathode on a MgF₂ entrance window. Experiments on measuring the amplitude distributions and counting rates due to Cherenkov radiation from the radioactive solutions of⁹⁰Sr−⁹⁰Y,¹³⁷Cs−¹³⁷Ba, and⁴⁰K were performed. The sensitivity and lowest measurable activity for water samples of⁹⁰Sr−⁹⁰Y was estimated on the basis of the results obtained, 4 figures, 3 tables, 11 references. Russian Science Center “Kurchatov Institute.” Translated from Atomnaya énergiya, Vol. 88, No. 4, pp. 282–286, April, 2000.     

<Superscript>239</Superscript>Pu prompt fission neutron spectra

Calculations of ²³⁹Pu(n, F) prompt fission neutron spectra have been performed for neutron energy up to 20 MeV. The exclusive spectra of pre-fission neutron reactions (n, xnf) were calculated on the basis of the Hauser-Feshbach model simultaneously with the cross sections of (n, F) and (n, 2n) reactions. The spectra of neutrons emitted by fission fragments were approximated by a sum of two Watt distributions. The components of the prompt fission neutron spectra due to pre-fission neutrons are manifested in the prompt fission neutron spectra and the average neutron energy. A correlation is established between this effect in the contribution of emissive fission (n, xnf) in the fission cross-section of ²³⁹Pu(n, F) and ²³⁵U(n, F). It is shown that the ²³⁹Pu(n, F) prompt fission neutron spectra used in applied calculations do not correspond to the experimental differential data and the systematic regularities in the spectra and their average energy found for the most carefully studied nuclei ^235,238U and ²³²Th. __________ Translated from Atomnaya énergiya, Vol. 103, No. 2, pp. 119–124, August, 2007.