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Incorporation of bone seeking alpha-emitting radionuclides such as 241Am are of special concern, due to the potential of alpha particles to damage the extremely radiation-sensitive bone marrow. In the case of an internal contamination with 241Am, direct in vivo measurements using Gamma-detectors are typically used to quantify the incorporated activity. Such detectors need to be calibrated with an anatomical phantom, for example of the skull, of known 241Am activity that reproduces the anatomy of the measured individual as closely as possible. Any difference in anatomy and material composition between phantom and individual will bias the estimation of the incorporated activity. Consequently, in this work the impact of the most important anatomical parameters on detection efficiency of one of the germanium detectors of the Helmholtz Center Munich (HMGU) partial body counter were systematically studied. For that a detailed model of the germanium detector was implemented in the Monte Carlo codes GEANT4 and MCNPX. To simulate the detector efficiency, various skull voxel phantoms were used. By changing the phantom dimensions and geometry the impact of parameters such as shape and size of the skull, thickness of tissue covering the skull bone, distribution of 241Am across the scull and within the skull bone matrix, on the detector efficiency was studied. Approaches to correct for these parameters were specifically developed for three physical skull phantoms for which Voxel phantoms were available: Case 102 USTUR phantom, Max-06 phantom, BfS phantom. Based on the impact of each parameter, correction factors for an ‘individual-specific’ calibration were calculated and applied to a real 241Am contamination case reported in 2014. It was found that the incorporated 241Am activity measured with the HMGU partial body counter was about twice as large as that estimated when using the BfS skull phantom without applying any correction factor for person-specific parameters. It is concluded that the approach developed in the present study should in the future be applied routinely for skull phantom measurements, because it allows for a considerably improved reconstruction of incorporated 241Am using partial body counters.

The International Commission on Radiological Protection (ICRP) has embarked on a process to review and revise the current System of Radiological Protection (‘the System’). To stimulate discussion, the ICRP published two open-access articles: one on aspects of the System that might require review, and another on research that might improve the scientific foundation of the System. Building on these articles, the ICRP organized a Workshop on the Future of Radiological Protection as an opportunity to engage in the review and revision of the System. This digital workshop took place from 14 October–3 November 2021 and included 20 live-streamed and 43 on-demand presentations. Approximately 1500 individuals from 100 countries participated. Based on the subjects covered by the presentations, this summary is organized into four broad areas: the scientific basis, concepts and application of the System; and the role of the ICRP. Some of the key topics that emerged included the following: classification of radiation-induced effects; adverse outcome pathway methodologies; better understanding of the dose–response relationship; holistic and reasonable approaches to optimization of protection; radiological protection of the environment; ethical basis of the System; clarity, consistency and communication of the System; application of the System in medicine and application of the principles of justification and optimization of protection.

Since 2012, the European Radiation Dosimetry Group (EURADOS) has developed its Strategic Research Agenda (SRA), which contributes to the identification of future research needs in radiation dosimetry in Europe. Continued scientific developments in this field necessitate regular updates and, consequently, this paper summarises the latest revision of the SRA, with input regarding the state of the art and vision for the future contributed by EURADOS Working Groups and through a stakeholder workshop. Five visions define key issues in dosimetry research that are considered important over at least the next decade. They include scientific objectives and developments in (i) updated fundamental dose concepts and quantities, (ii) improved radiation risk estimates deduced from epidemiological cohorts, (iii) efficient dose assessment for radiological emergencies, (iv) integrated personalised dosimetry in medical applications and (v) improved radiation protection of workers and the public. This SRA will be used as a guideline for future activities of EURADOS Working Groups but can also be used as guidance for research in radiation dosimetry by the wider community. It will also be used as input for a general European research roadmap for radiation protection, following similar previous contributions to the European Joint Programme for the Integration of Radiation Protection Research, under the Horizon 2020 programme (CONCERT). The full version of the SRA is available as a EURADOS report (www.eurados.org).

A new electronic radon/thoron monitor employing semiconductor detectors based on a passive diffusion chamber design has been recently developed at the Helmholtz Zentrum Munchen (HMGU). This device allows for acquisition of alpha particle energy spectra, in order to distinguish alpha particles originating from radon and radon progeny decays, as well as those originating from thoron and its progeny decays. A Monte-Carlo application is described which uses the Geant4 toolkit to simulate these alpha particle spectra. Reasonable agreement between measured and simulated spectra were obtained for both 220 Rn and 222 Rn , in the energy range between 1 and 10 MeV. Measured calibration factors could be reproduced by the simulation, given the uncertainties involved in the measurement and simulation. The simulated alpha particle spectra can now be used to interpret spectra measured in mixed radon/thoron atmospheres. The results agreed well with measurements performed in both radon and thoron gas environments. It is concluded that the developed simulation allows for an accurate prediction of calibration factors and alpha particle energy spectra.

MELODI is the European platform dedicated to low-dose radiation risk research. From 7 October through 10 October 2013 the Fifth MELODI Workshop took place in Brussels, Belgium. The workshop offered the opportunity to 221 unique participants originating from 22 countries worldwide to update their knowledge and discuss radiation research issues through 118 oral and 44 poster presentations. In addition, the MELODI 2013 workshop was reaching out to the broader radiation protection community, rather than only the low-dose community, with contributions from the fields of radioecology, emergency and recovery preparedness, and dosimetry. In this review, we summarise the major scientific conclusions of the workshop, which are important to keep the MELODI strategic research agenda up-to-date and which will serve to establish a joint radiation protection research roadmap for the future.

Background and purpose: Systematic investigation of the energy and angular dependence of secondary neutron fluence energy distributions and ambient dose equivalents values (H*(10)) inside a pencil beam scanning proton therapy treatment room using a gantry. Materials and methods: Neutron fluence energy distributions were measured with an extended-range Bonner sphere spectrometer featuring 3 He proportional counters, at four positions at 0 degrees, 45 degrees, 90 degrees, and 135 degrees with respect to beam direction and at a distance of 2 m from the isocenter. The energy distribution of secondary neutrons was investigated for initial proton beam energies of 75 MeV, 140 MeV, and 200 MeV, respectively, using a 2D scanned irradiation field of 11 x 11 cm(2) delivered to a 30 x 30 x 30 cm(3) PMMA phantom. Additional measurements were performed at a proton energy of 118 MeV including a 5 cm range-shifter (PMMA), yielding a Bragg peak position similar to that of 75 MeV protons. Results: Ambient dose equivalent values from 0.3 mu Sv/Gy (75 MeV;90 degrees) to 24 mu Sv/Gy (200 MeV;0 degrees) were measured inside the treatment room at a distance of 2 m from the isocenter. H*(10) values were lower (by factors of up to 7.2 (at 45 degrees)) at 75 MeV compared to those at 118 MeV with the 5 cm range-shifter. At 0 degrees and 45 degrees, an evaporation peak was found in the measured neutron fluence energy distributions, at neutron energies around MeV, which contributes about 50% to total H*(10) values, for all investigated proton beam energies. Conclusions: This study showed a pronounced increase of secondary neutron H*(10) values inside the proton treatment room with increasing proton energy without beam modifiers. For example, in beam direction this increase was about a factor of 50 when protons of 75 MeV and 200 MeV were compared. The existence of a peak of secondary neutrons in the MeV region was demonstrated in beam direction (0 degrees). This peak is due to evaporation neutrons produced in the existing surrounding materials such as those used for the gantry. Therefore, any simulation of the secondary neutrons within a proton treatment room must take these materials into account. In addition, the results obtained here show that the use of a range-shifter increases the production of secondary neutrons inside the treatment room. Using a range-shifter, the higher neutron doses observed mainly result from the higher incident proton energy (118 MeV instead of 75 MeV when no range-shifter was used), due to higher neutron production cross-sections. (C) 2017 American Association of Physicists in Medicine

International audience; Since autumn 2012, the European Radiation Dosimetry Group (EURADOS) has been developing its Strategic Research Agenda (SRA), which is intended to contribute to the identification of future research needs in radiation dosimetry in Europe. The present article summarises-based on input from EURADOS Working Groups (WGs) and Voting Members-five visions in dosimetry and defines key issues in dosimetry research that are considered important for the next decades. The five visions include scientific developments required towards (a) updated fundamental dose concepts and quantities, (b) improved radiation risk estimates deduced from epidemiological cohorts, (c) efficient dose assessment for radiological emergencies, (d) integrated personalised dosimetry in medical applications and (e) improved radiation protection of workers and the public. The SRA of EURADOS will be used as a guideline for future activities of the EURADOS WGs. A detailed version of the SRA can be downloaded as a EURADOS report from the EURADOS website (www.eurados.org).

United States Transuranium and Uranium Registries (USTUR) Case 0102 was the first whole-body donation to the USTUR (1979), of a worker affected by a substantial accidental 241Am intake(1). Half of this man’s skeleton, encased in tissue-quivalent plastic, provides a unique human ‘phantom’ for calibrating in vivo counting systems. In this case, the 241Am skeletal activity was measured 25 y after the intake. Approximately 82 % of the 241Am remaining in the body was found in the bones and teeth. The241Am activity concentration throughout the skeleton (in all types of bone) was fairly uniform(2). A protocol has been proposed by a group of in vivo laboratories from Europe [CIEMAT-Spain, IRSN-France and Helmholtz Zentrum Mu¨nchen (HMGU)-Germany] and Canada (HML) participating in this DOS/USTUR intercomparison. The focus areas for the study included: (1) the efficiency pattern along the leg phantom using Germanium detectors (experimental and computational), (2) the comparison of Monte Carlo (MC) results with experimental values in counting efficiency data and (3) the inflence of americium distribution in the bone material (volume or surface).

A Bonner multi-sphere spectrometer has been installed in 2005 at the Environmental Research Station 'Schneefernerhaus' (2660 m above sea level) on the Zugspitze mountain, Germany, to measure the energy spectrum of cosmic-ray neutrons at high altitudes continuously. The system can be used to investigate small temporal variations in the cosmic radiation intensity. For example, measurements were done during periods of 2 Forbush decreases of the cosmic radiation intensity in July and September 2005, respectively. The results were compared with those obtained by using neutron monitors, and neutron fluence spectra measured during these events are presented and discussed.

This work compares the results of four different unfolding codes, MSANDB, MAXED, FRUIT and BONMA, which are based on different unfolding techniques. Additionally, Bayesian parameter estimation is also considered. All unfolding codes were supplied with the same set of input data acquired at the Environmental Research Station 'Schneefernerhaus' on the Zugspitze mountain, corresponding to continuous measurements of secondary neutrons from cosmic radiation. The HMGU high-energy extended Bonner sphere spectrometer (BSS), consisting of 16 measuring channels with (3)He proportional counters, was used as a reference BSS. The differences in the neutron spectra obtained with the different unfolding codes are discussed, and the uncertainties of integral quantities, like neutron fluence and ambient dose equivalent, are quantified.

Two examples of individual dose assessment of workers in special monitoring programs are presented, a uranium and an americium incorporation case. It is demonstrated that careful model modifications lead to better dose estimates but that in many cases an optimisation of parameters is not necessary to get a reliable assessment of the committed effective dose. In some cases the use of individual SEE values might be more sensitive with regard to the committed effective dose than very sophisticated modifications of biokinetic models.

Since 1987, 134Cs and 137Cs activities have been measured in about 250 soil samples and about 350 samples of different fungal species grown in a coniferous forest in Bavaria, Germany. Variations of 137 Cs 134 Cs ratios are less than 10% within samples from the same soil horizon and year. Similarly, 137 Cs 134 Cs ratios vary within less than 10% in mushroom samples of the same species and year. In contrast, the specific activities of 134Cs and 137Cs in soil samples of the same horizon and in mushroom samples of the same species vary by up to one order of magnitude. Two approaches are presented to estimate mycelium location of fungi. In the static approach, 137 Cs 134 Cs ratios in soil and mushrooms, corrected to May 1986 and averaged over 1987–1994, are analysed. These ratios range from 1.74 ± 0.06 in the L-horizon to 2.41 ± 0.46 in the B-horizon. The corresponding ratios measured in 14 fungal species vary between 1.73 ± 0.12 (Lepista nebularis) and 2.16 ± 0.26 (Russula cyanoxantha). By comparing these ratios, information on the major mycelium location can be gained. In the dynamic approach, the change with time of the 137 Cs 134 Cs ratio in 14 fungal species and in different layers of forest soil is compared. At the investigated site, both approaches yield similar results. The advantages of both methods are discussed.

Caesium-134 and 137 Cs measurements in about 250 samples from L-, Of-, Oh-, Ah- and B-horizons of a Bavarian forest from 1987 to 1994 are analysed with respect to migration by using a compartment model. The derived ecological half-lives are 2.8 years, 3.8 years, 4.4 years and 7.7 years, respectively. By using these results, caesium behaviour can be predicted for about 25 years. The resulting profile is similar to that found nowadays for weapons fallout caesium, migrating within about 25 years in the same forest. Therefore, the model is suitable for the estimation of future behaviour of radiocaesium in the forest investigated for a period of about 25 years after deposition.

The active radon exposure meter developed recently at the German Research Center for Environmental Health (Helmholtz Zentrum Munchen) was used to measure radon concentrations in 12 tombs located in the Valley of the Kings, Egypt. Radon concentrations in air between 50 ± 7 and 12 100 ± 600 Bq m(-3) were obtained. The device was also used to measure individual radon exposures of those persons working as safeguards inside the tombs. For a measurement time of 2-3 d, typical individual radon exposures ranged from 1800 ± 400 to 240 000 ± 13 000 Bq h m(-3), depending on the duration of measurement and radon concentration in the different tombs. Based on current ICRP dose conversion conventions for workers and on equilibrium factors published in the literature for these tombs, individual effective dose rates that range from 1.5 ± 0.3 to 860 ± 50 µSv d(-1) were estimated. If it is assumed that the climatic conditions present at the measurement campaign persist for about half a year, in this area, then effective doses up to ∼ 66 mSv could be estimated for half a year, for some of the safeguards of tombs where F-values were known. To reduce the exposure of the safeguards, some recommendations are proposed.

The radiation field at flight altitudes is generated by the interaction of the primary cosmic radiation from space with atoms of the atmosphere. The cosmic particle flux is significantly higher on board aircraft than at the ground level and its intensity depends on latitude, altitude, solar activity and solar eruptions. Owing to the complexity of the field of secondary cosmic radiation—in fact this field consists of a variety of different particles including neutrons, protons, electrons, positrons, photons, positive and negative muons, etc., with kinetic energies exceeding the GeV range—there is no dosemeter system available so far that is able to cover the dose contributions of these particles separately.

Two Bonner sphere spectrometers (BSSs) have recently been installed to measure secondary neutrons from cosmic radiation continuously, one at the environmental research station 'Schneefernerhaus' at an altitude of 2650 m in Germany and the other at the Koldewey station close to the North Pole in Ny-Alesund, Spitsbergen. After unfolding, both systems provide neutron fluence energy distributions as a function of time. Based on these distributions and on fluence-to-dose conversion coefficients, mean ambient dose equivalent rate values of 75.0 +/- 2.9 nSv h(-1) and 8.7 +/- 0.6 nSv h(-1) were obtained for October 2008, respectively (quoted uncertainties represent standard deviations of 124 values obtained during the measurement period). Ambient dose equivalent rates measured by means of an extended rem counter at the Schneefernerhaus agree with those based on the BSS neutron energy distributions within 5 %. The ambient dose equivalent rate was also calculated based on simulated FLUKA neutron energy distributions in the atmosphere. Even without detailed modelling of the local environment, an agreement better than 30 % was obtained between the ambient dose equivalent rate based on the FLUKA distributions and those based on the BSS measurements at the Schneefernerhaus, for neutrons above about 20 MeV. This agreement is expected to be even better if the influence of the local environment on the measured neutron fluence energy distribution will be calculated.

The assessment of the exposure to cosmic radiation onboard aircraft is one of the preoccupations of bodies responsible for radiation protection. Cosmic particle flux is significantly higher onboard aircraft than at ground level and its intensity depends on the solar activity. The dose is usually estimated using codes validated by the experimental data. In this paper, a comparison of various codes is presented, some of them are used routinely, to assess the dose received by the aircraft crew caused by the galactic cosmic radiation. Results are provided for periods close to solar maximum and minimum and for selected flights covering major commercial routes in the world. The overall agreement between the codes, particularly for those routinely used for aircraft crew dosimetry, was better than ±20% from the median in all but two cases. The agreement within the codes is considered to be fully satisfactory for radiation protection purposes. © The Author 2009. Published by Oxford University Press. All rights reserved.

EPCARD.Net as completely new code is based on the same approved physical algorithm as EPCARD version 3.34. As a major feature, many significant changes were made in the information technology area. There are only a few physical improvements adopted in the parameters database of the new EPCARD.Net. These are mainly 'dynamic' fluence-to-dose conversion coefficients and the most recent model of the world grid cut-off rigidity. Differences between EPCARD.Net and EPCARD version 3.34 are discussed in terms of effective dose. These differences turned out to be less than approximately 8 %.

Dose assessment procedures for cosmic radiation exposure of aircraft crew have been introduced in most European countries according to the corresponding European directive and national regulations (1). The radiation exposure due to solar particle events is still a matter of scientific research (2). Several in-flight measurements were performed during solar storm conditions. First models to estimate the exposure due to solar particle events have been discussed. Recently EURADOS (European Radiation Dosimetry Group, http://www.eurados.org/) has started to coordinate research activities in model improvements for dose assessment of solar particle events. This paper describes the outline and preliminary results of a work package related to the European project CONRAD (Coordinated Network for Radiation Dosimetry) on complex mixed radiation fields at working places. The major aim of a subgroup of that work package is the validation of models for dose assessment of solar particle events, using data from neutron ground level monitors, in-flight measurement results obtained during a solar particle event and proton satellite data.

Resumo Existen relaciones muy estrechas entre los nematodos de los Scolytidos juntados a Araucaria araucaria y A. angustifolia y los nematodos de los Scolytidos paleartidos. En el caso de estas comunidades se trata de isosinusias. La edad minima de la associacion que se compone de estos nematodos y los Scolytidos es probablamente cincuenta milliones anos. Esto se deduce de la distribucion actual y fossil de las araucarias.

Die wesentlichsten morphologisch-anatomischen Merkmale zur Bestimmung des physiologischen Alters der Imagines von Boophthora erythrocepahala und einigen anderen Simuliidenarten des Untersuchungsgebietes sind die Malpighischen Gefase, der Fettkorper und die Gonade der Muckenweibchen. Zur Bestimmung des physiologischen Alters und zur Abgrenzung der nulliparen von den paren Mucken reicht oft ein Merkmal wie beispielsweise der Fettkorper nicht aus. Er ist in einzelnen Generationen, vor allem wahrend der Sommermonate, haufig so schwach entwickelt, wie dies sonst bei Mucken mit einem gonotrophischen Zyklus der Fall ist. Nur die Gonade ermoglicht dann, aufgrund des Restkorpers, die sichere Differenzierung. Eine Bestimmung der gonotrophischen Zyklen nach der Anzahl der auftretenden Dilatationen war sowohl im Laborexperiment als auch bei Freilandpopulationen von Boophthora erythrocephala, Odagmia ornata und Wilhelmina salopiensis nicht moglich. Die Mannchen konnen nach dem derzeitigen Stand der Untersuchungen nur in junge und alte Individuen differenziert werden. Die Muckenweibchen fliegen zu Beginn der Vegetationsperiode bald nach dem Schlupfen die Weidetiere an. Ihre Gonade hat mindestens schon das Entwicklungsstadium IIa erreicht. Vollkommen autogene Weibchen konnten weder bei Boophthora erythrocephala noch bei Odagmia ornata ornata festgestellt werden. Wahrend der Flugperiode im Sommer und Herbst fliegen nullipare und pare Mucken verschiedenen Alters in taglich wechselnden Anteilen an der Gesamtpopulation die Weidetiere an.

Results of in vivo measurements are presented, for a worker who was accidentially contaminated with 241 Am approximately 26 years earlier. The skeletal burden was measured by means of one HPGe detector positioned at different regions of the head. Activities in both lungs and the liver were measured by means of four HPGe detectors. Present activity estimates are about 6600 ± 600 Bq for the skeleton, about 400 ± 60 Bq for the lung, and about 80 ± 30 Bq for the liver. For this case, corresponding results of excretion measurements are 35.8 ± 2.5 mBq per day for urine, and 14.5 ± 2.4 mBq per day for faeces. The results are compared with those from other laboratories, and discussed in terms of currently available biokinetic models. The model used in ICRP Publication 78 is modified in order to describe all experimental data, and dose estimates are given.