Search

Activity measurements of 3 H, 241 Am and 60 Co solutions were performed to compare digital coincidence modules used at PTB and POLATOM for TDCR and 4πβ(LS)-γ coincidence counting. The activities determined with various coincidence modules connected in parallel to the same counter at PTB were found to be consistent. Observed discrepancies caused by differences in the coincidence resolving time did not exceed 0.14%. Accidental coincidences simulated by a frequency generator were registered, and the coincidence resolving time was determined., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Application of a new coincidence module using the pulse-mixing method in the 4π(LS)-γ coincidence system with TDCR detector in the beta channel (TDCRG) is presented. The pulse-mixing method extended for the TDCR system with gamma channel was compared with the classical coincidence method where the coincidence resolving time is introduced. The characteristics of the resolving and dead time of the above two methods were investigated. The level of accidental coincidences in the system was determined. The new developed coincidence module was validated by activity measurement of a set of 51 Cr, 54 Mn, 60 Co, 65 Zn, 85 Sr and 134 Cs standards., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A bilateral comparison between ENEA-INMRI (Italy) and NCBJ RC POLATOM (Poland) of 131 I-solution activity measurements was organized in the year 2015 and piloted by POLATOM, which provided the sources for the comparison. The 131 I master solution was standardized independently at both institutes by using Liquid Scintillation Counting and ionization chamber techniques. The 131 I master solution was then sent by POLATOM to the BIPM International Reference System (SIR). The comparison was registered as an EURAMET.RI(II)-K2.I-131 key comparison allowing the ENEA-INMRI result to enter in the SIR database., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

An international key comparison, identifier CCRI(II)-K2.Ge-68, has been performed. The National Institute of Standards and Technology (NIST) served as the pilot laboratory, distributing aliquots of a 68 Ge/ 68 Ga solution. Results for the activity concentration, C A , of 68 Ge at a reference date of 12h00 UTC 14 November 2014 were submitted by 17 laboratories, encompassing many variants of coincidence methods and liquid-scintillation counting methods. The first use of 4π(Cherenkov)β-γ coincidence and anticoincidence methods in an international comparison is reported. One participant reported results by secondary methods only. Two results, both utilizing pure liquid-scintillation methods, were identified as outliers. Evaluation using the Power-Moderated Mean method results in a proposed Comparison Reference Value (CRV) of 621.7(11)kBqg -1 , based on 14 results. The degrees of equivalence and their associated uncertainties are evaluated for each participant. Several participants submitted 3.6mL ampoules to the BIPM to link the comparison to the International Reference System (SIR) which may lead to the evaluation of a Key Comparison Reference Value and associated degrees of equivalence., (Published by Elsevier Ltd.)

The gamma emitting impurities in 99m Tc solution obtained from enriched molybdenum 100 Mo metallic target after its irradiation in a cyclotron were measured using a high-purity germanium (HPGe) detector. The radioactivity range of tested samples of 99m Tc was rather low, in the range from 0.34 to 2.39 MBq, thus creating a challenge to investigate the standard measurement HPGe system for impurity detection and quantification. In the process of 99m Tc separation from irradiated target the AnaLig® Tc-02 resin, Dionex H + and Alumina A columns were used. Fractions of eluates from various steps of separation process were taken and measured for radionuclidic purity. The overall measurement sensitivity of gamma emitters in terms of minimum detectable activity (MDA) was found at the level of 14-70Bq with emission lines in range of 36 - 1836keV resulting in impurity content range of 6.7 × 10 -4 to 3.4 × 10 -3 % for 93 Tc, 93m Tc, 94 Tc, 94m Tc, 95 Tc, 95m Tc, 96 Tc 96 Nb, 97 Nb, 99 Mo contaminants and 9.4 × 10 -3 % for 97m Tc. The usefulness of the chosen measurement conditions and the method applied to testing the potential contaminators was proved by reaching satisfactory results of MDAs less than the criteria of impurity concentration of all nuclides specified in the European Pharmacopoeia., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The aim of the work was to develop new radioactive standard sources based on epoxy resins. The optimal proportions of the components and the homogeneity of the matrices were determined. The activity of multigamma sources prepared in Marinelli beakers was determined with reference to the National Standard of Radionuclides Activity in Poland. The difference of radionuclides activity values determined using calibrated gamma spectrometer and the activity of standard solutions used are in most cases significantly lower than measurement uncertainty limits. Sources production method and quality control procedure have been developed., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

A new technology for the production of radiopharmaceutical (90)Y microspheres in the form of spherical yttrium oxide grains obtained by sol-gel method has been described. The authors present and discuss the results of investigations performed in the development of new production technology of yttrium microspheres and determination of their physic-chemical properties. The final product has the structure of spherical yttrium oxide grains with a diameter 25-100μm, is stable and free from contaminants. Irradiation of 20mg samples of grains with diameter of 20-50μm in the thermal neutron flux of 1.7×10(14)cm(-2)s(-1) at the core of MARIA research nuclear reactor allowed to obtain microspheres labelled with the (90)Y isotope on the way of the nuclear reaction (89)Y(n, ɤ)(90)Y. Specific activity of irradiated microspheres has been determined by application of absolute triple to double coincidence ratio method (TDCR) and has been evaluated at 190MBq/mg Y. (90)Y microspheres prepared by the proposed technique can be regarded as a promising medical material for radioembolization of liver malignancies., (Copyright © 2016 Elsevier B.V. All rights reserved.)

The standardisation of (111)In by 4π(LS)-γ coincidence and anticoincidence counting is presented. Absolute measurements were performed for samples with different concentrations of carrier solution and for different window settings in the gamma channel. The radioactive concentration of the master solution determined on the same reference date was consistent for all measurements performed. The evaluated typical uncertainty was 0.43%. The half-life of (111)In was determined using a time series of measurements performed with an ionisation chamber. A least squares fit of the measured data resulted in a half-life of 2.8067 (34) days consistent with Decay Data Evaluation Project recommended value (0.064% higher than the DDEP value)., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Radionuclidic purity tests of (18)F radiopharmaceuticals (Na(18)F and fluorodeoxyglucose [(18)F]FDG) and radionuclide composition analysis of irradiated water [(18)O]H2O were performed. The measurements were conducted using a High-Purity Germanium (HPGe) detector and a liquid scintillation counter. Radionuclide identification and activity measurements were performed for samples from different stages of the production process. Most of the impurities were detected on QMA (quaternary methylammonium) anion exchange columns and in liquid wastes. Using liquid scintillation counting, the activity of (3)H resulting from the (18)O[p, (3)H](16)O reaction was determined. It was shown that all of the impurities were efficiently determined and eliminated in the radiopharmaceuticals synthesis process and that the final products meet the requirements set by relevant regulations., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The Radioisotope Centre POLATOM organized a proficiency test of activity measurements of (90)Y and (89)Sr with nuclear medicine departments in Polish hospitals. Radioactive solutions used in this exercise were standardized by the TDCR method using the measurement systems of the National Standard of Radionuclides Activity in Poland. Results were analysed in compliance with ISO/IEC 17043:2010 (ISO, 2010) by calculating z scores and ζ (zeta) scores. The overall performance of the participants varied significantly. The sources of errors appeared to be the values of the calibration factor used during activity assay and the underestimation of uncertainties by the participants., (© 2013 Published by Elsevier Ltd.)

Standardization of (153)Sm by 4π(LS)-γ coincidence and anticoincidence counting and the CIEMAT/NIST method in three LS-counters is presented. This short half-life radionuclide is applied in tumor therapy and bone pain palliation. A simplified disintegration scheme of (153)Sm was applied in the calculation of the counting efficiency. Standard uncertainties of 0.4% for the (153)Sm measurements by the 4π(LS)-γ coincidence and anticoincidence techniques and 0.7% by the C/N method were evaluated, respectively. An agreement of the standardization results by both methods within the respective uncertainties was obtained. The half-life of (153)Sm of (1.92895±0.00024) days was determined during one month of measurements and correction for europium isotope impurities by the C/N method in the TriCarb 2910 LS-counter., (© 2013 Published by Elsevier Ltd.)

A new analytical procedure for (90)Sr determination in freshly milked (90)Y from a (90)Sr/(90)Y generator is described. To a solution containing 125 mg of Sr a 200 to 400 MBq sample of (90)Y is added and strontium is separated from (90)Y using DGA column of 1 mL volume. (90)Sr is recovered in a yield close to 100% and counted in a liquid scintillation spectrometer (LSC). The separated strontium is slightly contaminated with (90)Y in the range from 7 to 19% of (90)Sr activity. The separation and counting can be completed within 30 min. The detection limit in 900 s counting time is equal to about 0.2 Bq. This corresponds to (90)Sr/(90)Y activity ratio of 10(-8) level., (Copyright © 2013 Elsevier B.V. All rights reserved.)

An international Key Comparison of (177)Lu has recently been carried out. Twelve laboratories performed assays for radioactivity content on aliquots of a common master solution of (177)Lu, leading to eleven results submitted for entry into the Key Comparison Database of the Mutual Recognition Arrangement. A proposed Comparison Reference Value (CRV) was calculated to be 3.288(4)MBq/g using all eleven results. Degrees of equivalence and their uncertainties were calculated for each laboratory based on the CRV. Most of the values reported by the participating laboratories were within 0.6% of the CRV., (Copyright © 2012. Published by Elsevier Ltd.)

A (85)Sr solution was measured in two liquid scintillation (LS) counters. Scintillation pulses from the delayed transitions in the (85)Sr decay were by and large lost as the dead time of the LS-counter was much longer than the lifetime of the (85)Rb excited level. The registration probability of these pulses has been defined and introduced into the counting efficiency calculation. The results of the (85)Sr solution standardization by the CIEMAT/NIST and the TDCR methods relative to the results from the 4π(LS)-γ coincidence and anticoincidence method were 0.997±0.012 and 0.971±0.019, respectively., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

The Radioisotope Centre (RC) has organized for the first time in Polish hospitals a comparison of activity measurements of (99)Tc(m) and (131)I. From the 58 Polish hospitals invited, 37 participated in the comparison. Each participant got about 4 mL of (99)Tc(m) eluate and two (131)I capsules, low- and high-activity. Sources were standardized in the RC before dispatch using a 4pi ionization chamber calibrated by standard solutions. Participants used their own radionuclide calibrators. The measurement results were evaluated using the E(n) criterion and the z'-score. From all 118 measurement results received from participants, 75 results (64%) lay within +/-5% of the RC value, and 99 results (84%) lay within +/-10.0%., (Copyright 2009 Elsevier Ltd. All rights reserved.)