Cyclotron production of <Superscript>169</Superscript>Yb: a potential radiolanthanide for brachytherapy

In the present study, ytterbium-169 was produced via the ¹⁶⁹Tm(p, n)¹⁶⁹Yb nuclear process at the AMIRS (Cyclone-30, IBA, Belgium) cyclotron, irradiating Tm₂O₃ with proton particles of 15 MeV primary energy and 20 μA current for 20 min. Deposition of Tm₂O₃ on Cu substrate was carried out via by the sedimentation method. The 543 mg of thulium(III)oxide with 108 mg of ethyl cellulose and 8 mL of acetone were used to prepare a Tm₂O₃ layer of 11.69 cm². Yields of about 0.643 MBq ¹⁶⁹Yb per μAh were experimentally obtained. ¹⁶⁹Yb was separated in 80 ± 5% radiochemical yield using liquid–liquid extraction. Solvent extraction of no-carrier-added ¹⁶⁹Yb from irradiated thulium(III)oxide target hydrochloric solution was investigated using di-(2-ethylhexyl)phosphoric acid (HDEHP).     

Production and chemical separation of <Superscript>48</Superscript>V

Summary Vanadium-48 was produced with an activity of 222 MBq (6 mCi) by the ^natTi(d,xn)⁴⁸V nuclear reactions in the U-120 cyclotron. The energy of the irradiating beam was 13 MeV, its intensity 5 μA, and the metallic Ti target dimension 11’11 mm² (0.1 mm thickness). For target cooling, circulated water in target backside was used. After 3 cooling days, only ⁴⁸V and some ⁴⁶Sc (T_1/2 = 83.8 d), produced by the side nuclear reaction ⁴⁸Ti(d,α)⁴⁶Sc were found in the target. For production of the radiotracer of ⁴⁸V and for the preparation of source for standardization of ⁴⁸V by 4πβ-γ coincidence, the Ti target was dissolved either in HF or in H₂SO₄. For both dissolving methods an ion-exchange separation procedure was developed.     

<Superscript>47</Superscript>Sc production development by cyclotron irradiation of <Superscript>48</Superscript>Ca

The therapeutic radionuclide ⁴⁷Sc was produced through the ⁴⁸Ca(p,2n) channel on a proton beam accelerator. The obtained results show that the optimum proton energies are in the range of 24–17 MeV, giving the possibility to produce ⁴⁷Sc radionuclide containing 7.4% of ⁴⁸Sc. After activation, the powdery CaCO₃ target material was dissolved in HCl and scandium isotopes were isolated from the targets. The performed separation experiments indicate that, due to the simplicity of the operations and the chemical purity of the obtained ⁴⁷Sc the best separation process is when scandium radioisotopes are separated on the 0.2 µm filter.     

Targetry and specification of <Superscript>167</Superscript>Tm production parameters by different reactions

In recent years, there has been a rapid expansion in the use of radio nuclides for therapeutic purposes. Thulium–167 is an important radionuclide (T _1/2 = 9.25 d) due to it could be used for tumor and bone studies in nuclear medicine. ¹⁶⁷Tm complexed with hydroxy ethylene diamine tetra-acetic acid (HEDTA) could be used with the aim of bone imaging. ¹⁶⁷Tm emits a prominent γ ray of 208 keV energy and low energy electrons. This study describes calculations on the excitation functions of ¹⁶⁵Ho(α,2n)¹⁶⁷Tm, ¹⁶⁷Er(p,n)¹⁶⁷Tm, ^natEr(d,xn)¹⁶⁷Tm and ^natEr(p,xn)¹⁶⁷Tm reactions by ALICE/ASH (hybrid and GDH models) and TALYS-1.0 codes. In addition, calculated data by codes were compared to experimental data that earlier were published and TENDL-2010 database. Moreover, optimal thickness of the targets and physical yield were obtained by SRIM (stopping and range of ions in matter) code for each reaction. According to the results, the ¹⁶⁷Er(p,n)¹⁶⁷Tm and ¹⁶⁵Ho(α,2n)¹⁶⁷Tm reactions are suggested as the best method to produce ¹⁶⁷Tm owing to minimum impurities. The TALYS-1.0 code, predict the maximum cross-section of about 382 mb at 11 MeV and 849 mb at 26 MeV for ¹⁶⁷Er(p,n)¹⁶⁷Tm and ¹⁶⁵Ho(α,2n)¹⁶⁷Tm reactions, respectively. Finally, deposition of ^natEr₂O₃ on Cu substrate was carried out via the sedimentation method. The 516 mg of erbium(III)oxide with 103.2 mg of ethyl cellulose and 8 mL of acetone were used to prepare a ^natEr₂O₃ layer of 11.69 cm². ¹⁶⁷Tm was produced via the ^natEr(p,n)¹⁶⁷Tm nuclear process at 20 μA current and 15 → 7 MeV protons beam (1 h). Yield of about 3.2 MBq ¹⁶⁷Tm per μA h were experimentally obtained.     

Simultaneous determination of <Superscript>89</Superscript>Sr and <Superscript>90</Superscript>Sr: comparison of methods and calculation techniques

The presence of ⁸⁹Sr and ⁹⁰Sr in the biosphere constitutes a biological hazard. There are several analytical methods for the determination of ⁸⁹Sr and ⁹⁰Sr. Three analytical methods of various application fields using selective Sr resin for Sr separation and DGA resin for Y separation and measuring techniques, i.e. liquid scintillation spectrometry and Cerenkov counting are discussed in the paper. The calculation techniques are compared in the aspects such as trueness and accuracy of the results and the limit of detection. Uncertainties and detection limits are calculated using the spreadsheet method.     

Radiochemical separation and quality assessment for the <Superscript>68</Superscript>Zn target based <Superscript>64</Superscript>Cu radioisotope production

The radiochemical separation of the different radionuclides (⁶⁴Cu, ⁶⁷Cu, ⁶⁷Ga, ⁶⁶Ga, ⁵⁶Ni, ⁵⁷Ni, ⁵⁵Co, ⁵⁶Co, ⁵⁷Co, ⁶⁵Zn, ¹⁹⁶Au) induced in the Ni supported Cu substrate — ⁶⁸Zn target system, which was bombarded with the 29.0 MeV proton beam, was performed by ion-exchange chromatography using successive isocratic and/or concentration gradient elution techniques. The overlapped gamma-ray spectrum analysis method was developed to assess the ⁶⁷Ga and ⁶⁷Cu content in the ⁶⁴Cu product and even in the post-⁶⁷Ga production ⁶⁸Zn target solution without the support of radiochemical separation. This method was used for the assessment of ⁶⁴⁺⁶⁷Cu radioisotope separation from ⁶⁷Ga, the quality control of ⁶⁴Cu product and the determination of the ⁶⁸Zn (p,2p)⁶⁷Cu reaction yield. The improvement in the targetry and the optimization of proton beam energy for the ⁶⁸Zn target based ⁶⁴Cu and ⁶⁷Ga production were proposed based on the stopping power and range of the incident proton and on the excitation functions, reaction yields and different radionuclides induced in the target system.     

Studies on the adsorption of <Superscript>125</Superscript>I on bromide coated silver rods for the preparation of <Superscript>125</Superscript>I-seeds for brachytherapy applications

This article presents the development, the testing and the efficiency estimation of a system for the monitoring of the atmospheric concentration of radon using a detector ionization chamber type in pulse mode for environmental measurements in which the measurement of the average value of the ionization current is completed with the recording of the impulses of the ionization current caused by the alpha disintegrations from the sensible volume of the detector.     

Determination of <Superscript>137</Superscript>Cs and <Superscript>85</Superscript>Sr transport parameters in fucoidic sand columns and groundwater system

The determination is based on the evaluation of experimentally obtained breakthrough curves using the erfc-function. The first method is founded on the assumption of a reversible linear sorption/desorption isotherm of radionuclides on solid phase with constant distribution and retardation coefficients, whereas the second one is based on the assumption of a reversible non-linear sorption/desorption isotherm described with the Freundlich equation, i.e., with non-constant distribution and retardation coefficients. Undisturbed cores of 5 cm in diameter and 10 cm long were embedded in the Eprosin-type cured epoxide resin column. In this study the so-called Cenomanian background groundwater was used as transport medium. The groundwater containing radionuclides was introduced at the bottom of the columns at about 4 mL h⁻¹ constant flow-rate. The results have shown that in the investigated fucoidic sands: (i) the sorption was in principle characterized by linear isotherms and the corresponding retardation coefficients of ¹³⁷Cs and ⁸⁵Sr, depending on the type of sample, were approximately 13 or 44 and 5 or 15, respectively; (ii) the desorption was characterized by non-linear isotherms, and the retardation coefficients of the same radionuclides ranged between 23–50 and 5–25, respectively. The values of the hydrodynamic dispersion coefficients of these radionuclides varied between 0.43–1.2 cm² h⁻¹.      

Flux calculation in LSNAA using an <Superscript>241</Superscript>Am-Be source

The CITATION code based on neutron diffusion theory is used for flux calculation inside voluminous sample in prompt gamma activation analysis with an isotopic neutron source (²⁴¹Am-Be). The code used the specific parameters related to energy spectrum source, irradiation system materials (shielding, reflector, etc.), geometry and elemental composition of the sample. The flux distribution (thermal and fast) was calculated on three-dimensional geometry for the system: source, air, and polyethylene and water cylindrical sample of 125 liters. The thermal flux was calculated in series of points inside the sample, and agreed with the results obtained by measurements with good statistical uncertainty. The maximum thermal flux was measured at distance of 4.1 cm and calculated at 4.3 cm by the CITATION code. Beyond a depth of 7.2 cm, the ratio of thermal flux to fast flux increases up to twice and allows us the optimization of the detection system in the scope of in-situ PGNAA.     

Separation of radioarsenic from irradiated germanium oxide targets for the production of <Superscript>71</Superscript>As and <Superscript>72</Superscript>As

A method for the separation of no-carrier-added arsenic radionuclides from the bulk amount of proton-irradiated GeO₂ targets as well as from coproduced radiogallium was developed. The radionuclides ⁶⁹Ge and ⁶⁷Ga produced during irradiation of GeO₂ were used as tracers for Ge and Ga in the experiments. After dissolution of the target the ratio of As(III) to As(V) was determined via thin layer chromatography (TLC). The extraction of radioarsenic by different organic solvents from acid solutions containing alkali iodide was studied and optimized. The influence of the concentration of various acids (HCl, HClO₄, HNO₃, HBr, H₂SO₄) as well as of KI was studied using cyclohexane. The optimum separation of radioarsenic was achieved using cyclohexane with 4.75 M HCl and 0.5 M KI and its back-extraction with a 0.1% H₂O₂ solution. The separation leads to high purity radioarsenic containing no radiogallium and <0.001% [⁶⁹Ge]Ge. The overall radiochemical yield is 93 ± 3%. The practical application of the optimized procedure in the production of ⁷¹As and ⁷²As is demonstrated and batch yields achieved were in the range of 75–84% of the theoretical values.     

Disequilibrium of dissolved <Superscript>234</Superscript>U/<Superscript>238</Superscript>U and <Superscript>210</Superscript>Po/<Superscript>210</Superscript>Pb in Greek rivers

For the first time, a radiological study for the dissolved ²³⁸U, ²³⁴U, ²¹⁰Pb and ²¹⁰Po was held in major Greek rivers across the country. ²³⁴U/²³⁸U activity ratios are above one in all samples and ²¹⁰Po/²¹⁰Pb activity ratios are respectively below the unit indicating the disequilibrium in the samples. Quite satisfactory correlations were observed among ²³⁴U and ²³⁸U as well as among ²¹⁰Po and ²¹⁰Pb values. Uranium isotopes were separated by ion exchange and electroplated on stainless steel plates. ²¹⁰Po was spontaneously deposited on nickel plates, while ²¹⁰Pb was indirectly determined through the ingrowth of ²¹⁰Po. The sources were measured by a-spectrometry.     

<Superscript>31</Superscript>P and <Superscript>51</Superscript>V MAS-NMR Characterisation of Mixed Vanadium and Titanium Phosphates Prepared from Molecular Precursors

Coprecipitation of mixed vanadium and titanium phosphates has been performed by reacting a mixed solution of vanadium alkoxide (VO(OPrⁿ)₃) and titanium alkoxide (Ti(OPrⁿ)₄) with anhydrous phosphoric acid (H₃PO₄). The goal is to obtain a mixture at a molecular level of phosphates with both acidic and redox properties. In protic solvents, such as propanol, the vanadium phosphate precipitation is slow, so, as indicated by the chemical analysis, the coprecipitation is not stoichiometric. The kinetics of precipitation of both vanadium and titanium phosphates are much faster in aprotic solvents such as tetrahydrofuran (THF) and result in homogeneous precipitates. ³¹P and ⁵¹V MAS-NMR experiments, have been used in order to characterise the homogeneity in these samples. Phase separation is observed upon heating at 700C.     

Porous ZrC-carbon microspheres as potential insoluble target matrices for production of <Superscript>188</Superscript>W/<Superscript>188</Superscript>Re

New microsphere sorbents are reported, which could find application in demanding radiation environments and especially as targets for the production of nuclear medicines by neutron irradiation. An easily-synthesized Zr anionic complex was introduced into quaternary amine-functionalised polystyrene-divinylbenzene-based anion-exchange resins by batch adsorption. Upon carbothermal reduction, the precursors were converted to porous carbon matrices containing particles of ZrC and ZrO₂ polymorphs. The most phase-pure material, ZrAX-1, possessed high surface area, multi-scale porosity and high mechanical strength. Adsorption of Re and W was investigated and its possible deployment as a reusable host for the production of ¹⁸⁸W/¹⁸⁸Re is discussed.     

Determination of <Superscript>3</Superscript>H, <Superscript>226</Superscript>Ra, <Superscript>222</Superscript>Rn and <Superscript>238</Superscript>U in Austrian ground- and drinking water

Screening measurements for ³H, ²²⁶Ra, ²²²Rn and ²³⁸U in ground water were performed within a ground- and drinking water project in Austria. The aim of this project is to get an overview of the distribution of natural radionuclide activity concentration levels in ground water bodies. In some cases this water is used for drinking water abstraction. In this paper methods and results of the screening measurements are presented. Regions with high activity concentrations were identified and in these regions further investigation for ²²⁸Ra, ²¹⁰Pb and ²¹⁰Po will be conducted.     

Preparation of <Superscript>26</Superscript>Al, <Superscript>59</Superscript>Ni, <Superscript>44</Superscript>Ti, <Superscript>53</Superscript>Mn and <Superscript>60</Superscript>Fe from a proton irradiated copper beam dump

The station for pions cancer therapy was operated at PSI from 1980 to 1992. After a cooling time of 12 years it’s made of copper beam dump was cut and samples were taken for analytical purposes. The sampling collected about 500 g of high active copper chips that can be used for separation of exotic radionuclides. The analyses by gamma spectrometry, LSC and AMS showed main nuclides present to be ⁶⁰Co, ⁵⁴Mn, ²²Na, ⁶⁵Zn, ²⁶Al, ⁵³Mn, ⁵⁹Ni, ⁶³Ni, ⁵⁵Fe and ⁶⁰Fe and ⁴⁴Ti with a daughter nuclide ⁴⁴Sc. In the frame of ERAWAST project a procedure combining selective precipitation and ion exchange for the separation of the rare radionuclides from the copper beam dump was developed. The proposed separation procedure is easy for remote controlled implementation in a hot cell. The ion exchange separation of Ni, Al, Mg, Ti and Fe was complete and high decontamination factors for copper and cobalt were achieved. Based on the developed procedure a remotely controlled system for separation of exotic radionuclides from the copper chips was set up. The full scale system was installed in a hot cell where high activity levels can be handled. In order to evaluate the reliability and functionality of the system extensive tests have been done. During the test period 13.86 g in total of the proton irradiated copper beam dump were processed for separation of ²⁶Al, ⁵⁹Ni, ⁵³Mn, ⁴⁴Ti and ⁶⁰Fe. The results showed that the system was operational and the radionuclide separation was selective with high chemical yield. The procedure manages as well the generated liquid wastes containing high level of ⁶⁰Co activity.     

Systematic radiochemical separation for the determination of <Superscript>99</Superscript>Tc, <Superscript>90</Superscript>Sr, <Superscript>94</Superscript>Nb, <Superscript>55</Superscript>Fe and <Superscript>59,63</Superscript>Ni in low and intermediate radioactive waste samples

A simple and rapid separation procedure was systemized for the determination of ⁹⁹Tc, ⁹⁰Sr, ⁹⁴Nb, ⁵⁵Fe and ^59,63Ni in low and intermediate level radioactive wastes. The integrated procedure involves precipitation, anion exchange and extraction chromatography for the separation and purification of individual radionuclide from sample matrix elements and from other radionuclides. After separating Re (as a surrogate of ⁹⁹Tc) on an anion change resin column, Sr, Nb, Fe and Ni were sequentially separated as follows; Sr was separated as Sr (Ca-oxalate) co-precipitates from Nb, Fe and Ni followed by purification using Sr-Spec extraction chromatographic resin. Nb was separated from Fe and Ni by anion exchange chromatography. Fe was separated from Ni by anion exchange chromatography. Ni was separated as Ni-dimethylglyoxime precipitates after the removal of ^134,137Cs and ^110mAg by Cs-phosphotungstate and AgCl precipitation, respectively. Finally, the radionuclide sources were prepared by precipitation for their radioactivity measurements. The reliability of the procedure was evaluated by measuring the recovery of chemical carriers added to a synthetic radioactive waste solution.     

Mixing of atmospheric <Superscript>210</Superscript>Pb and <Superscript>7</Superscript>Be and <Superscript>137</Superscript>Cs and <Superscript>90</Superscript>Sr fission products in four characteristic soil types

Depth distribution of atmospheric ²¹⁰Pb and ⁷Be and ⁹⁰Sr and ¹³⁷Cs fission products was measured in two types of aeolian soils (desert dust and volcanic ash), irrigated paddy soil and strongly acidic soil. The depth dependence of ²¹⁰Pb, ⁷Be and ¹³⁷Cs show that these radionuclides have been diffused as solid soil particles in surface soil layers. In aeolian soil layers, about 50% of ⁹⁰Sr were diffused in surface soil layer and the remaining 50% had penetrated to deeper layers. The half of the fission particles containing ⁹⁰Sr were shown to have decomposed over the past 35 years.     

DFT calculations of <Superscript>14</Superscript>N, <Superscript>17</Superscript>O,and <Superscript>2</Superscript>H NQR parameters: Investigation of hydrogen bond interactions in sulfapyridine crystalline structure

DFT calculations of electric field gradient (EFG) tensors at the sites of ¹⁴N, ¹⁷O, and ²H nuclei are carried out to characterize the hydrogen bond (HB) interactions in the sulfapyridine crystal structure. One-molecule (monomer) and hydrogen-bonded hexameric cluster models of sulfapyridine are constructed according to available X-ray coordinates where the proton positions are optimized. Then, EFG tensors are calculated for both monomer and target molecule in the hexameric cluster of sulfapyridine to show the effect of HB interactions on the tensors. The calculated EFG tensors are converted to the experimentally measurable nuclear quadrupole resonance (NQR) parameters: quadrupole coupling constant (C _Q ) and asymmetry parameter (η _Q ). The results reveal different contribution of various nuclei to N-H⋯N and N-H⋯O HB interactions in the cluster where the N2 and O1 have major contributions. The computations are performed with B3LYP and B3PW91 functionals DFT method and 6-311+G* and 6-311++G** standard basis sets using the Gaussian 98 package.     

Measurements of <Superscript>210</Superscript>Po and <Superscript>210</Superscript>Pb in total diet samples: Estimate of dietary intakes of <Superscript>210</Superscript>Po and <Superscript>210</Superscript>Pb for Japanese

To estimate the dietary intakes of ²¹⁰Pb and ²¹⁰Po for the Japanese adults and their annual effective doses, ²¹⁰Pb and ²¹⁰Po were measured for 240 daily diet samples collected at two locations of Ishikawa Prefecture in Japan over three years by duplicate portion studies. No appreciable differences in intake rates of ²¹⁰Pb and ²¹⁰Po and their ²¹⁰Po/²¹⁰Pb ratios were seen among the years in each district, and between the two districts. The intake rates evaluated using 240 diet samples were 0.20 Bq/d/p for ²¹⁰Pb and 0.61 Bq/d/p for ²¹⁰Po as a median, respectively. Annual effective doses of ²¹⁰Pb and ²¹⁰Po for Japanese adults were estimated to be 0.050 and 0.053 mSv/y, respectively.