The European intercomparison of in-vivo monitoring laboratories: the EIVIC-2020 project.

The EIVIC project was launched in 2020, and the main goal was the organisation of a European intercomparison of in-vivo monitoring laboratories dealing with direct measurements of gamma-emitting radionuclides incorporated into the body of exposed workers. This project was organised jointly by members of EURADOS Working Group 7 on internal dosimetry (WG7), the Federal Office for Radiation Protection (BfS, Germany) and the Radioprotection and Nuclear Safety Institute (IRSN, France). The objective was to assess the implementation of individual-monitoring requirements in EU Member States on the basis of in-vivo measurements and to gain insight into the performance of in-vivo measurements using whole-body counters. In this context, a total of 41 in-vivo monitoring laboratories from 21 countries, together with JRC (EC) and IAEA participated. The results were submitted in terms of activity (Bq) of the radionuclides identified inside phantoms that were circulated to all participants. The measured data were compared with reference activity values to evaluate the corresponding bias according to the standards ISO 28218 and ISO 13528. In general, the results of the different exercises are good, and most facilities are in conformity with the criteria for the bias and z-scores in the ISO standards. Furthermore, information about technical and organisational characteristics of the participating laboratories was collected to test if they had a significant influence on the reported results.

METHODOLOGY AT CIEMAT WHOLE BODY COUNTER FOR IN VIVO MONITORING OF RADIOIODINE IN THE THYROID OF EXPOSED POPULATION IN CASE OF NUCLEAR EMERGENCY.

Iodine-131 is one of the main concerns from the point of view of radiological protection in a short term after a nuclear accident. The WBC Laboratory of CIEMAT has developed a methodology for in vivo monitoring of radioiodine in the thyroid of exposed individuals in case of emergency. Thyroid-neck phantoms of different sizes are required for calibrating the detection systems in appropriate counting geometries for the measurement of exposed population. A Low-Energy Germanium (LEGe) detector and a Fastscan Counter were calibrated using a set of thyroid phantoms fabricated by CIEMAT. Each neck phantom consists of a Lucite cylinder with a vial source of 131I. Counting efficiencies depending on age and thyroid sizes were obtained to be used to determine the activity of 131I in internally contaminated people. DL of 131I varies with the age, being in the range of 5-8 Bq for the LEGe detector and 26-42 Bq for the Fastscan. Detection of intakes resulting in Committed Effective doses far below 1 mSv are guaranteed for thyroid monitoring in a few days after the accidental exposure assuming a scenario of acute inhalation or ingestion of 131I by members of the public.

EFFICIENCY STUDY OF A LEGe DETECTOR SYSTEM FOR THE ASSESSMENT OF 241Am IN SKULL AT CIEMAT WHOLE BODY COUNTER.

(241)Am incorporation due to an incident or chronic exposure causes an internal dose, which can be evaluated from the total activity of this isotope in the skeleton several months after the intake. For this purpose, it is necessary to perform in vivo measurements of this bone-seeker radionuclide in appropriate counting bone geometries with very low attenuation of surrounded tissue and to extrapolate to total activity in the skeleton (ICRP 89, Basic anatomical and physiological data for use in radiological protection: reference values. 2001. 265). The work here presented refers to direct measurements of americium in the Cohen skull phantom at the CIEMAT Whole Body Counter (WBC) using low-energy germanium (LEGe) detectors inside a shielding room. The main goal was to determinate the most adequate head counting geometry for the in vivo detection of americium in the bone. The calibration of the in vivo LEGe system was performed with four detectors with 2 cm of distance to Cohen phantom. Two geometries were measured, on junction of frontal to parietal bones and frontal bone. The efficiencies are very similar in both geometries, the preferred counting geometry is the most comfortable for the person, with the LEGe detectors in the highest part of the frontal bone, near the junction with the parietal bone, CIEMAT WBC participated in a skull intercomparison exercise organised by WG7 of EURADOS (European Radiation Dosimetry Group e.V.). Efficiencies using three different skull phantoms were obtained. Measurements were performed for different head counting positions, four of them in the plane of symmetry and others over the temporal bone. The detector was placed in parallel with the calibration phantom at a distance of 1 cm. The main gamma emission of (241)Am, 59.5 keV (36 %), was used for comparing efficiency values. The lower efficiency was obtained over the frontal and occipital bones. Measurement with one LEGe detector over the parietal bone is the most efficient. The activity of each skull phantom was calculated using CIEMAT head calibration. Results of the EURADOS intercomparison are presented here for discussion.

THE CHALLENGE OF CIEMAT INTERNAL DOSIMETRY SERVICE FOR ACCREDITATION ACCORDING TO ISO/IEC 17025 STANDARD, FOR IN VIVO AND IN VITRO MONITORING AND DOSE ASSESSMENT OF INTERNAL EXPOSURES.

The accreditation of an Internal Dosimetry Service (IDS) according to ISO/IEC 17025 Standard is a challenge. The aim of this process is to guarantee the technical competence for the monitoring of radionuclides incorporated in the body and for the evaluation of the associated committed effective dose E(50). This publication describes the main accreditation issues addressed by CIEMAT IDS regarding all the procedures involving good practice in internal dosimetry, focussing in the difficulties to ensure the traceability in the whole process, the appropriate calculation of detection limit of measurement techniques, the validation of methods (monitoring and dose assessments), the description of all the uncertainty sources and the interpretation of monitoring data to evaluate the intake and the committed effective dose.

EURADOS intercomparison on measurements and Monte Carlo modelling for the assessment of americium in a USTUR leg phantom.

A collaboration of the EURADOS working group on 'Internal Dosimetry' and the United States Transuranium and Uranium Registries (USTUR) has taken place to carry out an intercomparison on measurements and Monte Carlo modelling determining americium deposited in the bone of a USTUR leg phantom. Preliminary results and conclusions of this intercomparison exercise are presented here.

Prospects for detecting supersymmetric dark matter in the Galactic halo.

Dark matter is the dominant form of matter in the Universe, but its nature is unknown. It is plausibly an elementary particle, perhaps the lightest supersymmetric partner of known particle species. In this case, annihilation of dark matter in the halo of the Milky Way should produce gamma-rays at a level that may soon be observable. Previous work has argued that the annihilation signal will be dominated by emission from very small clumps (perhaps smaller even than the Earth), which would be most easily detected where they cluster together in the dark matter haloes of dwarf satellite galaxies. Here we report that such small-scale structure will, in fact, have a negligible impact on dark matter detectability. Rather, the dominant and probably most easily detectable signal will be produced by diffuse dark matter in the main halo of the Milky Way. If the main halo is strongly detected, then small dark matter clumps should also be visible, but may well contain no stars, thereby confirming a key prediction of the cold dark matter model.

[Novelties in the field of progression factors in chronic kidney disease]. / Novedades en el campo de los factores de progresión en la Enfermedad Renal Crónica.

The fight against chronic kidney disease is one of the most relevant aspects of nephrological practice, from both the perspective of clinical activity and research within the field of nephrology. In this brief article, we present in very summarized form some of the aspects in this field in the last year that the authors found of interest. Because the content of the next few pages was necessarily chosen on the basis of the authors' preferences, we assume that many other topics of great interest have been left out of this summary. In any case, we hope that this article will be interesting and useful and also serve as an subject of debate in nephrology forums.

Incidence of Beijing genotype of Mycobacterium tuberculosis in Elche, Spain: a 13-year surveillance study.

Strains of the Beijing genotype family of Mycobacterium tuberculosis have been associated with outbreaks and multidrug resistance. We performed a retrospective thirteen-year surveillance study (1993 - 2005) on the occurrence of this strain in Elche, Spain. Only one of the available isolates from 332 cases of tuberculosis tested positive for Beijing strain. The case, detected in 2001, was that of an immigrant patient from Senegal with pulmonary tuberculosis. The strain was not drug resistant and besides six close contact persons that were infected no secondary cases of this strain were detected. In the Elche area, the incidence of Beijing strains is very low and there is no evidence of transmission or higher virulence.

Acute and subchronic effects of gamma-hydroxybutyrate on isolation-induced aggression in male mice.

Gamma-hydroxybutyrate (GHB) is a new drug with abuse potential popularly known as "liquid ecstasy". It is an endogenous compound of the mammalian brain which satisfies many of the criteria for consideration as a neurotransmitter or neuromodulator. Preliminary studies have found that GHB (100-200 mg/kg) reduces aggressive behavior in mice. This study was designed to assess the effects of low and intermediate doses of GHB (5, 25, 50 and 100 mg/kg, ip) on isolation-induced aggression in male mice, using an ethopharmacological approach. Moreover, the possible development of tolerance after its subchronic administration for 15 consecutive days was also examined. Individually housed mice were exposed to anosmic "standard opponents" 30 min after drug administration, and the encounters were videotaped and evaluated using an ethologically based analysis. Acute treatment with GHB (25-100 mg/kg) significantly reduced offensive behaviors (threat and attack) without affecting immobility, whereas with the lowest dose used (5 mg/kg) a significant increase of attack behaviors was observed. This behavioral profile was maintained when GHB (25-100 mg/kg) was administered during 15 consecutive days, indicating an absence of tolerance to the initial antiaggressive action of the drug. However, the subchronic treatment with 5 mg/kg of GHB produced an opposite effect to that observed after single treatment, suggesting a possible desensitization of postsynaptic dopaminergic receptors.

Assessment of the internal dose of 241Am in bone by in vivo measurements of activity deposited in knee.

In case of chronic exposure or long time after an acute intake of (241)Am as a consequence of an incident, the assessment of internal dose might be realised by estimating the total activity content of this element in the skeleton. For this purpose, a new methodology has been developed at the Whole Body Counting Laboratory of CIEMAT. In vivo measurements of this bone-seeker radionuclide in the knee are performed using four low energy germanium detectors inside a shielded room. The sensitivity study of this technique resulted in a minimum detectable activity of 7 Bq, for a counting time of 1800 s. Extrapolation to the total activity in the bone has been carried out by taking into account that the bone content of the knee calibration phantom is equivalent to 10.7% of the whole skeleton mass. The results of in vivo measurements of population and the procedure for internal dose evaluation are presented here.

The Hamaker constant of anatase aqueous suspensions.

The linear relationship of the yield stress with the square zeta potential may be used to determine the Hamaker constants in suspensions. In this work we have obtained the Hamaker constant for the attractive forces between anatase particles in aqueous suspensions using this method and compared them with those obtained by contact angle measurement. The results show excellent agreement.

Monte Carlo based voxel phantoms for in vivo internal dosimetry.

The purpose of this communication is to describe briefly the computer programs developed to generate the MCNP input file corresponding to any segmented tomographic data and its application to the calibration procedures for in vivo internal dosimetry. The method has been applied to the determination of 241Am in bone by measurement in skull and knee using MCNP voxel models of a real human head and knee based on the tomographic Voxelman and Arms Down phantoms developed by Zubal et al. at Yale University.

[Update on gamma-hydroxybutyric acid]. / Actualización del ácido gamma-hidroxibutírico.

AIMS: The article offers an updated review of the main pharmacological aspects of gamma-hydroxybutyric acid (GHB), as well as its clinical and behavioural effects. DEVELOPMENT: A number of pharmacological, neurochemical and electrophysiological studies have clearly shown that endogenous GHB plays a role as a neurotransmitter and/or neuromodulator in the central nervous system (CNS). GHB displays specific synthesis, release and reuptake mechanisms, as well as particular binding sites that suggest the existence of a central GHBergic system. This substance, popularly known as 'liquid ecstasy', is also a potentially abusable drug; if administered for prolonged periods of time it can lead to dependence and withdrawal symptoms after the patient stops taking it. Its chief behavioural actions include sedation/sleepiness, induction of absence seizures, catalepsy or reduced aggression, among others. Some of these effects appear to be related to an interaction that has been reported to exist between the GHBergic system and the dopaminergic and GABAergic receptors in the CNS. From the clinical point of view, its use has been approved in some countries to treat the narcoleptic syndrome, and it has also been considered for possible use in the treatment of alcohol or opiate abuse. Finally, recent studies conducted with laboratory animals suggest the existence of a possible neurotoxic effect following prolonged administration in abusable dosages. CONCLUSIONS: GHB is an extraordinarily interesting compound. It acts as a neurotransmitter/neuromodulator in the CNS. It is also an abusable recreational drug and may also be used to treat a number of different pathological conditions, the most important of which is narcolepsy. The possible development of neurotoxicity following prolonged administration, however, imposes considerable limitations on its usefulness in clinical contexts.

Intrinsic viscosity of SiO2, Al2O3 and TiO2 aqueous suspensions.

The viscosity of dilute suspensions of several metal oxides (SiO2, Al2O3 and TiO2) was measured at different pH values. The intrinsic viscosity, [eta], was derived from the concentration dependence of the viscosity. This magnitude was pH-dependent. A correlation with the shape of the kinetic unity has been proposed.

Effects of (+)SKF 10047, a sigma-1 selective agonist, on isolation-induced aggression in male mice.

sigma-1 Receptors have been identified in numerous brain regions, including areas such as hypothalamus and amygdala, which have long been linked to the regulation of aggression. However, there is no clear information with respect to the possible effects of sigma-1 ligands on aggressive behavior in laboratory animals. Consequently, the present study examined the effects of (+)SKF 10047 (0.5-6 mg/kg, i.p.), a sigma-1 prototypical agonist, on isolation-induced aggression in male mice, using an ethopharmacological approach. Individually housed mice were exposed to anosmic "standard opponents" 30 min after drug administration. Ten minutes of diadic interactions were staged between a singly housed and an anosmic mouse in a neutral area. The encounters were videotaped, and the accumulated time allocated by subjects to 10 broad behavioral categories was estimated using an ethologically based analysis. Results showed that (+)SKF 10047 (6 mg/kg) produced a significant reduction of offensive behaviors, without affecting immobility. Social investigation behaviors were also slightly increased after drug treatment (2-6 mg/kg). These results suggest a role for sigma-1 receptors in aggression modulation in mice.

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