Isomeric yield ratios in the photoproduction of 52m,gMn from natural iron using 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung

The isomeric yield ratios for the ^natFe(γ,xn1p)^52m,gMn reactions have been measured by the activation and the γ-ray spectroscopic methods at 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung energies. The high purity natural iron foils in disc shape were irradiated with uncollimated bremsstrahlung beams of the Pohang Accelerator Laboratory. The induced activities in the irradiated foils were measured by the high-resolution γ-ray spectrometry with a calibrated high-purity Germanium (HPGe) detector. In order to improve the accuracy of the experimental results the necessary corrections were made in the gamma activity measurements and data analysis. The obtained isomeric yield ratios for the ^natFe(γ,xn1p)^52m,gMn reactions at 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung energies are 0.27 ± 0.03, 0.33 ± 0.04, 0.34 ± 0.04, and 1.25 ± 0.15, respectively. The present results at 50-, 60-MeV, and 2.5-GeV bremsstrahlung energies are the first measurements. We found that the isomeric yield ratio of the ^natFe(γ,xn1p)^52m,gMn reaction depends on the incident bremsstrahlung energy and the mass difference between the product and the target nucleus when we compared the present results with other experimental data at different energies.     

Separation of the no-carrier-added 109Cd from Ag, Cu and 65Zn by use of a precipitation and AG1-X8 resin

The ¹⁰⁹Cd radionuclide was produced in the cyclotron via ^natAg(p,n)¹⁰⁹Cd reaction. The radiochemical separation of ¹⁰⁹Cd from silver and non-isotopic impurities comprised of two stages. The optimum conditions of the ¹⁰⁹Cd separation methods were: Ag precipitation with 0.015 M HCl and Cu and ⁶⁵Zn by use of 0.015 M HCl on AG1-X8 strong anion-exchange resin. Chemical and radionuclidic purity of ¹⁰⁹Cd were measured by ICP-AES and gamma-ray spectrometry respectively. Recovery yield and radionuclidic purity were obtained 99.7% and 99%, respectively.     

Production method of no-carrier-added186Re

No-Carrier-Added¹⁸⁶Re was produced using the¹⁸⁶W(p,n)¹⁸⁶Re nuclear reaction with 13.6 MeV protons on thick targets of 99.79% isotopically enriched¹⁸⁶WO₃. The theoretical excitation functions for producing¹⁸⁶Re, and possible radionuclidic impurities of¹⁸²Re,¹⁸³Re, and¹⁸⁴Re were calculated using the ALICE code. Cross-sections of the¹⁸⁶W(p,n)¹⁸⁶Re reaction were measured up to 20 MeV using the stacked target method with thin foils of natural composition tungsten metal. The experimental and theoretical excitation functions were in good agreement. Targetry used at the TIARA cyclotron, and a radiochemical separation scheme for¹⁸⁶Re are described.     

Contribution to the radioanalytical determination of heavy metals in the working environment of welders

Heavy metals can be the most important toxic substances in welding environments. Their chemical behavior is related to welding aerosols; hence, reliable analysis of these aerosols is quite important. Activation analysis by fast neutrons (14 MeV), and radionuclidic X-ray fluorescence analysis (241-Am source) were used to determine selected metals (Fe, Mn, Cr, Ni, Mo) in aerosols produced during welding of high-alloy steels with MIG technology. Sampling was done by filtration using micro-pore filters. A multichannel analyzer (MCA S80 CANBERRA) and Si/Li, Ge/Li detectors were used to process the analytical signals. Appropriate statistical parameters were calculated.     

Optimization of the production of [61Cu]Diacetyl-bis(N 4-methylthiosemicarbazone) for PET studies

Summary Copper-61 produced via the ^natZn(p,x)⁶¹Cu nuclear reaction was used for the preparation of [⁶¹Cu]diacetyl-bis(N⁴-methylthiosemicarbazone) ([⁶¹Cu]ATSM) (4) using a house-made ATSM ligand. After a proton irradiation of an electroplated zinc layer by 22 MeV protons at 180 mA for 3.2 hours, ⁶¹Cu was recovered by two-step chromatography using a cation and an anion exchange column. About 222 GBq (6.00 Ci) of ⁶¹Cu²⁺ was obtained with a radiochemical separation yield of more than 95% and a radionuclidic purity of better than 99%. Colorimetric methods showed that traces of chemical impurities in the product were below the accepted limits. The [⁶¹Cu]ATSM production was optimized for reaction conditions (buffer concentration and temperature) with a radiochemical yield of higher than 80%, radiochemical purity of better than 98% and a specific activity of about 246 Ci/mmol. The produced [⁶¹Cu]ATSM is a PET radiotracer for hypoxia imaging with an intermediate half life and a satisfactory quality, suitable for future PET studies.     

Preparation of manganese-53

The nuclide⁵³Mn was produced by the following three nuclear reactions,⁵²Cr(d, n)⁵³Mn,⁵¹V(³He n)⁵³Mn and⁵⁰Cr(α, n), (α, p)⁵³Mn. Enriched⁵²Cr and⁵⁰Cr metal targets were prepared on copper plate holder by electrodeposition. The commercially available natural vanadium foil was used for the⁵¹V(³He, n)⁵³Mn reaction. Each target was bombarded in a cyclotron. Manganese was extracted and purified without using carrier from the bombarded targets by anion and cation exchanges and solvent extraction. The isotopic ratio⁵³Mn/⁵⁵Mn was measured by mass spectrometry and the amount of⁵⁵Mn was determined by neutron activation analysis. The activity of⁵³Mn obtained was 7 dpm by 750 millicoulombs in³He bombardment (E³He=20 MeV). The activity due to by-product⁵⁴Mn was about several thousands times higher than that of⁵³Mn in³He and deuteron bombardments, which were produced through⁵¹V(³He, γ)⁵⁴Mn and⁵³Cr(d, n)⁵⁴Mn. In alpha bombardment (E_α=15 MeV), the activity of⁵³Mn produced was 8 dpm by 95 millicoulombs. The activity ratio, dpm⁵⁴Mn/dpm⁵³Mn, was about 3, and this ratio was the best one among the results so far obtained.     

Production of123I on linear electron accelerator using highly-enriched124Xe

Highly enriched xenon¹²⁴Xe /99.85%/ has been used for the experimental production of iodine¹²³I by the /,n/ reaction. As the radiation source served a 30–45 MeV electron beam produced by a linear accelerator and converted by a tungsten converter to -radiation. The yield and radionuclidic purity of¹²³I have been estimated, the content of isotopic impurities /¹²⁴I and¹²⁵I/ being for 30 MeV irradiations lower than 4×10^–3%/.     

Production of iodine-124

Iodine-124 is produced in high yield by the¹²⁴Te/d, 2n/¹²⁴I reaction and >99.5% radionuclidic purity at 48 h post irradiation. The production yield was 0.55±0.06 mCi/Ah. Radiochemical separation and targetry methodology are described.For earlier papers in this series see: R.M. Lambrecht and M. Sajjad, Radiochimica Acta /in press/.     

Trial preparation and evaluation of a 81mKr-generator for medical use

A prototype 81mKr-generator consisting of an ion exchange column and some attachments for handling was prepared on trial. Parent nuclide 81Rb obtained by the reaction of 82Kr(p, 2n)81Rb was absorbed on the resin, and radionuclidic purity, sterility and apyrogenicity of the generator eluate were examined. Analysis of gamma-ray spectrum obtained with a Ge(Li) detector and a multichannel pulse height analyzer revealed that the nuclidic purity of the 81mKr in the eluate was 99.997-99.999% with 0.001-0.003% of 79Kr at the start of the elution. Sterility and apyrogenicity of the eluate were proved by J.P. sterility test and limulus test respectively. All results obtained show that the 81mKr-generator is very suitable for medical application.     

Rapid determination of molar ratios in binary systems by 14 MeV neutron activation analysis

The magnetic characteristics of barium ferrite, a compound widely used for magnetic materials, depend on the molar ratio of iron(III) oxide to barium oxide. On account of this fact, activation analysis using 14 MeV neutrons was applied for the rapid and non-destructive determination of the molar ratio of iron(III) oxide to barium oxide in barium ferrite. Iron was detected as⁵⁶Mn produced from the⁵⁶Fe(n, p)⁵⁶Mn reaction, and barium as^137mBa originating from the¹³⁸Ba(n, 2n)^137mBa reaction. A linear relation was obtained between the ratio of counts of⁵⁶Mn and^137mBa and the molar ratio of iron(III) oxide to barium oxide; the corrected gradient of the experimental calibration curve, obtained with^137mBa internal standard, agreed well with the calculated value. The molar ratios of iron(III) oxide to barium oxide obtained by activation analysis and by chemical analysis were in good agreement.     

Rapid determination of molar ratios in binary systems by 14 mev neutron activation analysis

The 14 MeV neutron activation analysis method was applied for the rapid and non-destructive determination of the molar ratios of iron(III) oxide and zinc oxide in zinc ferrites. Iron was detected as⁵⁶Mn produced from⁵⁶Fe by the (n, p) reaction, and zinc as the sum of the coincidence counts of the annihilation radiations of the positrons emitted from⁶³Zn and⁶⁴Cu produced from⁶⁴Zn by the (n, 2n) and (n, p) reactions respectively. The ratios of the counts of⁵⁶Mn and the sum of the coincidence counts were not linearly related to the molar ratios of iron(III) oxide and zinc oxide in zinc ferrites. However, by corrections of the mutual contributions to the counts, linear relations were obtained between the ratios of the counts and the molar ratios when the corrected sum of the coincidence counts was used as an internal standard. The experimental and theoretical slopes of the analytical lines agreed within a difference of approximately 10%. The deviations between the results of the activation analysis and those of the chemical analysis were less than 5% of the chemical results.     

A compilation of cross-sections for the reaction (n, 2n) with 14 MeV neutrons for some important fusion reactor structural materials

A compilation of the cross section (n, 2n) for⁴⁶Ti,^{50, 52, 54}Cr,⁵⁵Mn,^54,56Fe,⁵⁹Co,^58,59Ni,⁹³Nb,^92,100Mo with 14 MeV neutrons is presented in the form of a table containing the results of nearly 190 different measurements, mainly obtained by activation analysis. Brief assessment of the experimental methods and the data status are given.     

Development of [103Pd]-2-acetylpyridine 4 N-methyl thiosemicarbazone complex for targeted therapy

Summary Due to interesting biological properties of palladium-thiosemicarbazono complexes, production of a ¹⁰³Pd-labeled anti-cancer complex, i.e., [¹⁰³Pd]-2-acetylpyridine ⁴N-methylthiosemicarbazone ([¹⁰³Pd]-APMTS) was developed. Palladium-103 (T_1/2 = 16.96 d) produced via the ¹⁰³Rh(p,n)¹⁰³Pd nuclear reaction using natural rhodium target, was separated from the irradiated target material. Proton energy was 18 MeV with 200 mA irradiation for 15 hours (final activity 700 mCi of ¹⁰³Pd²⁺, RCY>95%, radionuclidic purity>99%). The final activity was eluted in form of Pd(NH₃)₂Cl₂ in order to react with 2-acetylpyridine-⁴N-methylthiosemicarbazone to yield [¹⁰³Pd]-APMTS. Chemical purity of the final product was confirmed to be within the accepted limits by polarography. [¹⁰³Pd]-APMTS was prepared with a radiochemical yield of more than 80% at room temperature after 3 hours. The labeling reaction was optimized for time, temperature and radioactivity and ligand ratio. A mixture of APMTS and Pd activity in ethanol was heated at 90 °C for 3 hours followed by reverse phase SPE purification using C₁₈ plus Sep-Pak. Radiochemical purity of more than 99% using RTLC and specific activity of about 12500 Ci/mol was obtained. The stability of the tracer was checked in the final product and the presence of human serum at 37 °C up to 3 hours. The partition coefficient of the final complex was determined by octanol : saline buffer distribution.     

Development of [<Superscript>64</Superscript>Cu]-DOTA-anti-CD20 for targeted therapy

Copper-64 was produced as a by-product of ⁵⁵Co via ⁶⁴Ni(p,n)⁶⁴Cu by 15 MeV proton bombardment of ^natNi resulting in a thick target yield of 5.31 MBq/μAh (143.5 μCi/μAh) and a radiochemical separation yield of 95% (radionuclide purity >97% after 25 hours of bombardment). Rituximab was successively labeled with [⁶⁴Cu]-CuCl₂. N-succinimidyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA-NHS) was prepared at 25 °C using DOTA and N-hydroxy succinimide (NHS) in CH₂Cl₂ followed by the addition of 1 ml of a Rituximab pharmaceutical solution. Radiolabeling was performed at 37 °C in 3 hours. Radio thin-layer chromatography showed an overall radiochemical purity of 90–95% at optimized conditions (specific activity=30 GBq/mg, labeling efficacy; 82%) using various chromatography systems. The final isotonic ⁶⁴Cu-DOTA-Rituximab complex was passed through a 0.22 μm filter and checked by gel electrophoresis for radiolysis control. Stability of the final product was checked in the formulation and in presence of human serum at 37 °C.     

Development of a process for routine production of123I using the127I(p, 5n)123Xe→123I reaction

The object of this paper is to give details of a production method for¹²³I, now in routine use at Harwell. We employ the (p, 5n) reaction, irradiating a liquid target of di-iodomethane (CH₂I₂) spiked with additional iodine, with 58 MeV protons. A yield of ∼9 mCi/μAh is obtained; the only detectable radionuclidic impurity is¹²⁵I, present to the extent of ∼0.15% by activity at the time of separation of Xe from I.     

Synthesis and structural characterization of high spin M/Cu (M = Mn, Fe) heterobimetallic and Fe/Cu2 trimetallic phosphinoamides

The heterobimetallic complexes [Mn((i)PrNPPh(2))(3)Cu((i)PrNHPPh(2))] (1) and [Fe((i)PrNPPh(2))(3)Cu((i)PrNHPPh(2))] (2) have been synthesized by the one pot reaction of LiN(i)PrPPh(2), MCl(2) (M = Mn, Fe), and CuI in high yield. Addition of excess CuI into 2 or directly to the reaction mixture led to the formation of a heterotrimetallic [Fe((i)PrNPPh(2))(3)Cu(2)((i)PrNPPh(2))] (3) in good yield. Complexes 1-3 have been characterized by means of elemental analysis, paramagnetic (1)H NMR, UV-vis spectroscopy, cyclic voltammetry, and single crystal X-ray analysis. In all three complexes, Mn or Fe are in the +2 oxidation state and have a high spin electron configuration, as evidenced by solution Evans' method. In addition, the oxidation state of Fe in complex 3 is confirmed by zero-field (57)Fe M?ssbauer spectroscopy. X-ray crystallography reveals that the three coordinate Mn/Fe centers in the zwitterionic complexes 1-3 adopt an unusual trigonal planar geometry.     

Proton activation analysis for chromium,nickel and copper

Proton activation analysis has been applied to develop a procedure for the simultaneous determination of chromium, nickel and copper. The procedure involves the bombardment of the sample with protons to induce⁵²Cr(p, n)^52mMn,⁶⁰Ni(p, n)⁶⁰Cu and⁶³Cu(p, n)⁶³Zn reactions. These reactions have been studied for proton energies from 11 MeV to 15 MeV. Thick target yields for the production of the indicator radionuclides as well as the sensitivities of the determination have been measured in this energy region and are compared with results obtained for other charged particle induced reactions. Detailed data are given on nuclear and instrumental interferences. The trace elements have been determined nondestructively and simultaneously in cobalt with a relative precision of 8 to 15%.     

Synthesis, crystal structures and catalytic abilities of new macrocyclic bis-pyridineamido Mn and Fe complexes

A new macrocyclic ligand H₂L (H₂L = 1,2-[bis(6′-pyridine-2′-carboxamido)-ethane]benzene) has been designed and synthesized by condensation of pyridine-carboxylic acid and diamine. Its Mn(III) and Fe(III) complexes, [Mn(L)Cl (DMF)] and [Fe(L)Cl], were prepared and respectively characterized by IR, UV-Vis, ESI-Mass, elemental analysis and X-ray single crystal diffraction. The catalytic abilities of them were examined, and up to 95% yield was achieved in epoxidation of styrene. The preliminary investigation of catalytic mechanism by manganese complex was carried out, suggesting the involvement of Mn(V) oxo species during catalysis.     

A compilation of charged particle production cross sections by 14 MeV neutrons for Ti,V, Cr and Mn isotopes

A compilation of the cross sections (n, p), (n, n′ p), (n, α), (n, n′ α) and (n, He³) for Ti-46,-47,-48,-49,-50; V-51; Cr-50,-52,-53,-54 and Mn-55 by 14 MeV neutrons is presented in the form of a table containing the results of some 170 different measurements, mainly obtained by activation analysis. Brief assessments of the experimental methods and the data status are given.     

Independent isomeric yield ratios of 95m,gNb in the natMo(γ, pxn) and natZr(p,xn) reactions

The independent isomeric yield ratios of ^95m,gNb from the ^natMo(γ, pxn) reactions with bremsstrahlung end-point energies of 45, 50, 55, 60, and 70 MeV were determined by an activation and an off-line γ-ray spectrometric technique at the Pohang accelerator laboratory (PAL), Korea. The isomeric yield ratios of ^95m,gNb from the ^natZr(p, xn) reactions were also determined in eight different proton energies within 19.4–44.7 MeV by a stacked-foil activation and an off-line γ-ray spectrometric technique using the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences (KIRAMS), Korea. The measured isomeric yield ratios of ^95m,gNb from the present work and the literature data in the ^natMo(γ, pxn) and ^natZr(p, xn) reactions were compared with the similar literature data in the ^natMo(p, αxn) reactions. It was found that the isomeric yield ratio of ^95m,gNb increases with projectile energy, which indicate the effect of excitation energy. However, at the same excitation energy, the isomeric yield ratios of ^95m,gNb in the ^natZr(p, xn) and ^natMo(p, αxn) reactions are higher than those in the ^natMo(γ, pxn) reaction, which indicates the role of input angular momentum. The isomeric yield ratios of ^95m,gNb in the ^natMo(γ, pxn), ^natZr(p, xn), and ^natMo(p, αxn) reactions were also calculated using computer code TALYS 1.4. The calculated isomeric yield ratios of ^95m,gNb from three reactions increase with excitation energy. However, in all the three reactions, the calculated values are significantly higher than the experimental data.