Main text Since 1978, 10 laboratories have submitted 18 samples of 67Ga to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ga-67. Recently, the CMI (Czechia) participated in the comparison and the key comparison reference value (KCRV) has been fully revised. The degrees of equivalence between each equivalent activity measured in the SIR and the updated KCRV have been calculated and the results are given in the form of a table. A graphical representation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Main text Three new participations in the BIPM.RI(II)-K1.Co-57 comparison have been added to the previous results and this has produced a revised value for the key comparison reference value (KCRV), calculated using the power-moderated weighted mean. A link has been made to the CCRI(II)-S6.Co-57 comparison piloted by the International Atomic Energy Agency (IAEA) in 2008 for which one sample of the 57Co radioactive solution was sent to the SIR. Two NMIs used the S6 comparison to update their degree of equivalence. The degrees of equivalence between each equivalent activity measured in the International Reference System (SIR) and the KCRV have been calculated and the results are given in the form of a table for the remaining seven NMIs in the BIPM.RI(II)-K1.Co-57 comparison and the three eligible participants in the CCRI(II)-S6.Co-57 comparison. A graphical presentation is also given. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/. The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Since 2009, four national metrology institutes (NMI) have submitted four samples of known activity of Cu-64 to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Cu-64. The values of the activity submitted were between about 3 MBq and 260 MBq. There are now five results in the BIPM.RI(II)-K1.Cu-64 comparison. A key comparison reference value (KCRV) has been calculated for the first time for this nuclide. The degrees of equivalence between each equivalent activity measured in the SIR and the KCRV have been calculated and the results are given in the form of a table. A graphical presentation is also given.

An international exercise, registered as EUROMET project no. 907, was launched to measure both the activity of a solution of (124)Sb and the photon emission intensities of its decay. The same solution was sent by LNE-LNHB to eight participating laboratories, six of which sent results for photon emission intensities both in absolute and in relative terms. From these results and including previous published values, a consistent decay scheme was worked out, proving that problems in activity measurements have not been due to decay scheme data.

An international exercise, registered as EUROMET project no. 907, was launched to measure both the activity of a solution of (124)Sb and the photon emission intensities of its decay. The same solution was sent by LNE-LNHB to eight participating laboratories. In order to identify possible biases, the participants were asked to use all possible activity measurement methods available in their laboratory and then to determine their reference value for comparison. Thus, measurement results from 4pibeta-gamma coincidence/anti-coincidence counting, CIEMAT/NIST liquid-scintillation counting, 4pigamma counting with well-type ionization chambers and well-type crystal detectors were given. The results are compared and show a maximum discrepancy of about 1.6%: possible explanations are proposed.

The activity of electron capture radionuclides is usually determined by 4pi(proportional counter, PC)-gamma coincidence counting. The corrections necessary for the final activity value calculation are obtained by an extrapolation method. Variation of the PC detection efficiency can be achieved through different methods, e.g. by changing the self-absorption of the source using absorbing foils or by adding carriers. Another possibility is a "wet" extrapolation method, which utilises an absorption change during the drying of a water droplet added onto the source surface. In this paper, slopes of extrapolation curves and resulting activity values obtained by different methods are compared for several radionuclides ((54)Mn, (139)Ce, (88)Y, (57)Co). In some cases a digital coincidence system was used for the analysis of measured data. The "wet" extrapolation, due to its very simple procedure, seems to be convenient for routine measurement and its accuracy is similar to the other methods.

In recent years the software coincidence counting system, designed for absolute activity measurement, has been developed in the Czech Metrology Institute. In this system a true coincidence count rate is calculated from the records of time and amplitude data of individual pulses and may be determined by two different methods. The first one uses a coincidence resolving time, in a manner similar to a classical coincidence measurement. The second method applies the pulse mixing method formulae, so that it does not use the resolving time and the correction for accidental coincidences. Both methods have been tested on the same data from a 4πβ (PC)-γ coincidence measurement of 60Co sources. The difference between the results obtained from both calculation methods applied on the data from the same measurement did not exceed 0.015%. The details of both methods and the results of their comparison are presented.

A system designed for absolute activity measurement is described using a digital method. The system is based on data recording from a coincidence measurement and subsequent software processing of the data records. The data acquisition device collects amplitudes of individual pulses from analogue-to-digital converters and supplies them with time information. Software processing of data records from this system offers many benefits in comparison to conventional coincidence counting, for example it enables to perform time and pulse height analysis and setting of coincidence parameters by using a wide variety of evaluation methods to one data record. The digital system was tested with a 4pi beta-gamma coincidence detectors arrangement consisting of a proportional counter and two NaI(Tl) scintillation detectors. The results obtained with a 60Co source are presented.

Previous research has indicated that intracerebral injection of potassium chloride, and the resultant electrical silence of the brain, lead to the attenuation of a previously conditioned emotional response; this response may reflect conditioned fear. The data reported here indicate that the normal mobilization of corticosteroids, perhaps a second index of emotionality, is also attenuated by such injections.

Drug Prescribing for Patients with Chronic Kidney Disease in General Practice: a Cross-Sectional Study