99mTc internal contaminations measurements among nuclear medicine medical personnel during ventilation - perfusion SPECT lung scans

This paper presents results of measurements of ^99mTc activity concentration in air and nuclear medical personnel blood during ventilation-perfusion SPECT lung scans. ^99mTc activity measurements were conducted at the Nuclear Medicine Department, John Paul II Hospital, Krakow. Technicians and nurses who perform examinations were equipped with personal aspirators enabling air sampling to determine the radiation exposure at their workplaces. Measurements allowed to evaluate the concentration of ^99mTc in 14 air samples and it ranged from 7800 ± 600 to 10,000 ± 1000 Bq m^-3 for air samples collected by technicians and from 390 ± 30 to 600 ± 40 Bq m^-3 for air samples collected by nurses. In addition ^99mTc concentrations in blood of medical personnel were determined in 24 samples. For technicians the maximum ^99mTc blood concentration levels reached 920 ± 70 Bq L^-1 and 1300 ± 100 Bq L^-1. In the case of nurses, the maximum estimated activity concentrations were about ten times lower, namely 71 ± 7 Bq L^-1 and 39 ± 3 Bq L^-1. Although the intakes appear to be relatively high, the resulting annual effective doses are about 34 µSv for technicians and only 2 µSv for nurses.

The radioactive contamination study in south-western Greenland tundra in 2012-2013

The paper presents results of the radioecological investigation carried out in south-western Greenland shoreline. There were examined over 50 samples of lichens and mosses collected from 7 locations during two scientific expeditions conducted in the summer of 2012-2013. The levels, trends and the most likely origin were determined for following natural and artificial radionuclides: ⁹⁰Sr, ¹³⁷Cs, ^{230, 232}Th, ^{234, 238}U, ^{238, 239+240}Pu and ²⁴¹Am. The radioactive pollution was found as relatively low, reaching the maximum values at: 25.3 ± 2.04 Bq/kg for ⁹⁰Sr, 293 ± 27 Bq/kg for ¹³⁷Cs, 4.01 ± 0.13 Bq/kg for ^239+240Pu, 0.1381 ± 0.0070 Bq/kg for ²³⁸Pu and 1.90 ± 0.21 Bq/kg of ²⁴¹Am, 9.15 ± 0.48 Bq/kg for ²³⁰Th, 25.1 ± 1.2 Bq/kg for ²³²Th, 7.5 ± 1.5 Bq/kg for ²³⁴U and 7.26 ± 0.80 Bq/kg for ²³⁸U. Both activity and mass isotopic ratio assays revealed dominant contribution of the global fallout + SNAP 9A on the presence of plutonium isotopes and ²⁴¹Am in Greenland tundra. However, noticeable deviations of ²⁴¹Am/^239+240Pu and to a lesser extend of ²⁴⁰Pu/²³⁹Pu ratios from the GF level have been observed. The origin of ¹³⁷Cs was evidently connected with the coexistence of global and Chernobyl fallout, while the presence of ⁹⁰Sr was caused by nuclear weapon tests and affected by leaching process. The seaborne signature of uranium isotopes was manifested in research material as well.

Sources and variation of isotopic ratio of airborne radionuclides in Western Arctic lichens and mosses

This research concerned radioactivity of lichens and mosses from coastal zones of the Canadian Arctic and Alaska. Over 50 samples were collected from 7 positions during two scientific expeditions in 2012 and 2013. The tundra contamination caused by anthropogenic radionuclides was relatively low, reaching mean values with SD's of: 17.4 ± 3.5 Bq/kg for ⁹⁰Sr, 14.0 ± 2.9 Bq/kg for ¹³⁴Cs, 38.4 ± 7.5 Bq/kg for ¹³⁷Cs, 0.86 ± 0.24 Bq/kg for ^239+240Pu, 0.065 ± 0.017 Bq/kg for ²³⁸Pu and 0.50 ± 0.13 Bq/kg for ²⁴¹Am. The increase of activity concentration with increasing latitudes was noticed mostly in regard to ⁹⁰Sr, Pu isotopes and ²⁴¹Am. The analysis of isotopic ratios exhibited dominant contribution of the global fallout (+SNAP 9A satellite re-entry fallout) for the presence of plutonium isotopes and ²⁴¹Am. The Fukushima fallout signature was identified in a few lichens from Alaska. However, the influence of additional unknown factor on the occurrence of ⁹⁰Sr and ¹³⁷Cs has been detected in western part of Canadian Arctic. Natural radioisotopes of thorium and uranium were found throughout the entire investigated region and the average values of activity concentration with SD's were as follows: 2.92 ± 0.47 Bq/kg for ²³⁰Th, 2.61 ± 0.48 Bq/kg for ²³²Th, 4.32 ± 0.80 Bq/kg for ²³⁴U and 3.97 ± 0.71 Bq/kg for ²³⁸U. Examined Western Arctic tundra was not affected with any technically enhanced natural radioactivity.

Adsorption of volatile polonium species on metals in various gas atmospheres: Part II – Adsorption of volatile polonium on platinum, silver and palladium

This work presents the results obtained from studying the interaction between polonium compounds formed in different atmospheres and platinum, palladium and silver surfaces obtained by thermochromatography. These results are of crucial importance for the design of cover gas filter systems for lead-bismuth eutectic (LBE)-based nuclear facilities such as accelerator driven systems (ADS). The results obtained from studying the interaction of polonium and platinum under inert atmosphere and reducing atmospheres with and without addition of moisture show that polonium is deposited at temperatures between 993 and 1221 K, with adsorption enthalpies ranging from –235 to –291 kJ mol−1, indicating a very strong adsorption of the polonium species present on platinum surfaces. The interaction between polonium and silver was investigated using purified inert, reducing and oxidizing carrier gases. Results show a deposition temperature between 867 and 990 K, with adsorption enthalpies ranging from –205 to –234 kJ mol−1. The interaction of polonium and palladium was studied in purified helium and purified hydrogen. For both conditions a deposition temperature of 1221 K was observed corresponding to an adsorption enthalpy of –340 kJ mol−1. No highly volatile polonium species was formed at any of the applied experimental conditions.

Radionuclides and heavy metal concentrations as complementary tools for studying the impact of industrialization on the environment

The aim of the study was to determine whether using chemical and radiochemical analysis of lake sediments can highlight changes in the climate. Also it was studied whether human impact on the environment can be observed and to what extent such changes are in agreement with historical data. Samples of 16 cm thick sediment cores from the Smreczynski Staw Lake were collected and divided into 1 cm thick sub-samples. The samples were air dried and homogenized. The quantitative analysis of Fe, Mn, Zn, Cr, Cu, Ni, Cd, and Pb in the digested sediment samples was made by using atomic absorption spectrometry. Simultaneously, the radioactivity of ¹³⁷Cs using gamma spectrometry and ²¹⁰Pb_uns using alpha spectrometry, were measured for sediment layer dating. Results showed that iron concentration was in the range 0.3–over 1 % (w/w), and zinc 0.01–0.05 % (w/w). Lesser concentrations were found for copper 18.37–43.6 ppm, manganese 37.5–50.7 ppm, lead 146.1–432 ppm, chromium 12.3–37.4 ppm, nickel 3.1–10.8 ppm and cadmium 0.9–34.6 ppm. Changes in ¹³⁷Cs radioactivity was in the range of 89 ± 11 to 865 ± 62 (Bq kg⁻¹). Sediments composition can accurately reflect (in terms of time and to what extent) air pollution and natural geo-chemical processes in the environment. However, the choice of the analysed object is crucial in this respect. The Smreczynski Staw Lake, due to its location in the mountains and hydrological situation, proved to be very useful for providing undisturbed analytical samples.

Physical and chemical limitations to preparation of beta radioactive stents by direct neutron activation

Pure beta emitters are the sources of choice for intracoronary irradiations in restenosis prevention. In this work we reconsidered preparation of low activity 32P sources by ion-implantation of stable 31P into highly biocompatible pure titanium stents, followed by neutron activation. Gamma-spectrometrical analysis has shown that during activations with high thermal neutrons flux production of gamma-active long-lived contaminants is much beyond the dosimetrically acceptable limit, mainly due to the competing (n,p) reactions induced by the fast neutrons on isotopes of the bulk stent material, and to a lesser extent due to (n,gamma) reactions on chemical impurities. A potential applicability of this method for obtaining alternative beta radioactive stents is discussed.

Radiochemical separation of no-carrier-added 177Lu as produced via the 176Yb(n,gamma)177Yb-->177Lu process

The 176Yb(n,gamma)177Yb-beta(-)-->177Lu process was investigated to provide no-carrier-added (nca) 177Lu. The radiochemical separation of the 177Lu from the macro-amounts of the ytterbium target based on the cementation process, i.e. the selective extraction of Yb by Na(Hg) amalgam from Cl-/CH3COO- electrolytes, followed by a final cation exchange purification. The cementation separation process provides a decontamination factor of Yb(III) of 10(4), the cation exchange purification adding a decontamination factor of > 10(2). The nca 177Lu is available in radiochemically pure form despite the chemical similarity of the lanthanides with 75 +/- 5% overall separation yield within 4-5 h. It can be used to synthesise nca 177Lu labelled radiotherapeuticals.