The European Radiation Dosimetry Group (EURADOS) was founded in 1982. Since then, the group has continuously developed and is currently a network of 80 institutions and more than 600 individual scientists across Europe, including exchange with the scientific community outside of Europe. EURADOS supports research and development of dosimetry and harmonising dosimetric practices. This paper describes the major milestones in the history of the organization. It starts from the very beginning when the idea was born and describes periods during which the role and strategy of the network had to be defined, elaborated and refined. Finally, it ends to date where EURADOS appears as an independent self-sustainable association, which is a reliable partner for various international organisations in radiation research and radiation protection. Major activities of EURADOS are highlighted such as (1) establishment and coordination of Working Groups, (2) regular organization of dosimetric intercomparisons for quality assurance of dosimetry procedures, (3) development and organization of education and training events, and (4) contributions towards the development of strategic and integrated radiation research in Europe.

The objective of microdosimetry was, and still is, to identify physical descriptions of the initial physical processes of ionising radiation interacting with biological matter which correlate with observed radiobiological effects with a view to improve the understanding of radiobiological mechanisms and effects. The introduction of therapy with particles starting with fast neutrons followed by negative pions, protons and light ions necessitated the application of biological weighting factors for absorbed dose in order to account for differences of the relative biological effectiveness (RBE). Dedicated radiobiological experiments in therapy beams with mammalian cells and with laboratory animals provided sets of RBE values which are used to evaluate empirical 'clinical RBE values'. The combination of such experiments with microdosimetric measurements in identical conditions offered the possibility to establish semi-empirical relationships between microdosimetric parameters and results of RBE studies.

The objective of the present study was to identify advantages and limitations of the application of microdosimetric concepts for inhaled radon progeny activities in the lungs. The methods employed for this analysis were a recently developed Monte-Carlo microdosimetry code for the calculation of energy deposition in bronchial target cells and the Probability Per Unit Track Length (PPUTL) model, which relates these microdosimetric parameters to cellular radiation effects. The major advantages of internal microdosimetry of radon progeny in bronchial airways are: (i) quantitative characterisation of non-uniform dose distributions and identification of target sites with enhanced carcinogenic potential, (ii) quantification of low doses of alpha particles by the number of cells hit and the dose received by those cells, (iii) illustration of the random variations of cellular doses by specific energy distributions and (iv) establishment of a direct link to cellular radiobiological effects. At present, a major limitation of microdosimetry is the extrapolation of the response of individual cells to the resulting tissue response, which is still not fully explored.

Since low dose effects of alpha particles are produced by cellular hits in a relatively small fraction of exposed cells, the present study focuses on alpha particle interactions in bronchial epithelial cells following exposure to inhaled radon progeny. A computer code was developed for the calculation of microdosimetric spectra, dose and hit probabilities for alpha particles emitted from uniform and non-uniform source distributions in cylindrical and Y-shaped bronchial airway geometries. Activity accumulations at the dividing spur of bronchial airway bifurcations produce hot spots of cellular hits, indicating that a small fraction of cells located at such sites may receive substantially higher doses. While presently available data on in vitro transformation frequencies suggest that the relative biological effectiveness for alpha particles ranges from about 3 to 10, the effect of inhomogeneous activity distributions of radon progeny may slightly increase the radiation weighting factor relative to a uniform distribution. Thus a radiation weighting factor of about 10 may be more realistic than the current value of 20, at least for lung cancer risk following inhalation of short-lived radon progeny.

The Ninth Symposium on Neutron Dosimetry has been expanded to cover not only neutron radiation but heavy charged particle dosimetry as well. The applications are found in such fields as radiation protection, aircrew dosimetry, medicine, nuclear power and accelerator health physics. Scientists from many countries from around the world presented their work, and described the latest developments in techniques and instrumentation.

The newsletter 'European Research in Radiological Sciences' is jointly published by the European Late Effects Project Group and the European Radiation Dosimetry Group to disseminate information about research projects and activities carried out under the EURATOM Framework Programme. Since May 2003, the Newsletter is operated interactively from the Internet. The new site uses a dedicated database that automatically generates HTML pages. This system developed at the University of Cambridge provides an innovative approach to improve the dissemination of project information.

The introduction of new ICRP recommendations, especially the new Human Respiratory Tract Model (HRTM) in ICRP Publication 66 led us to focus on some specific parameters related to industrial uranium aerosols collected between 1990 and 1999 at French nuclear fuel fabrication facilities operated by COGEMA, FBFC, and the CEA. Among these parameters, the activity median aerodynamic diameter (AMAD), specific surface area (SSA), and parameters describing absorption to blood f(r), s(r) and s(s) defined in ICRP Publication 66 were identified as the most relevant influencing dose assessment. This study reviewed the data for 25 pure and impure uranium compounds. The average value of AMAD obtained was 5.7 microm (range 1.1-8.5 microm), which strongly supports the choice of 5 microm as the default value of AMAD for occupational exposures. The SSA varied between 0.4 and 18.3 m2 g(-1). For most materials, values of the absorption parameters f(r), s(r), and s(s) derived from the in vitro experiments were generally consistent with those derived from the in vivo experiments. Using average values for each pure compound allowed us to classify UO2 and U3O8 as Type S, mixed oxides, UF4, UO3 and ADU as Type M, and UO4 as Type F based on the ICRP Publication 71 criteria. Dose coefficients were also calculated for each pure compound, and average values for each type of pure compound were compared with those derived using default values. Finally, the lung retention kinetics and urinary excretion rates for inhaled U03 were compared using material-specific and default absorption parameters, in order to give a practical example of the application of this study.

A Monte Carlo code has been developed to calculate the local energy deposited by alpha emitters deposited on the inner surface in the lung airway. Developed to deal further with airway bifurcations, this code has been as a first step validated in a cylindrical airway configuration by comparison with well-established analytical codes in the case of contamination of bronchiolar airways with actinides. The code has then been applied to the study of uniform and non-uniform contamination of cylindrical bronchial airways by radon progeny in indoor and mine exposure conditions. In addition to the microdosimetric spectra, the average microdosimetric parameters (zp, n, z) have been evaluated. The work currently in progress consists in adapting this developed Monte Carlo code to the configuration of an airway bifurcation with realistic particles deposition.

Measuring in vivo contamination remains a difficult task for some actinides such as Pu-239 due to the high absorption of low energy X rays associated with alpha decay. X rays and low energy gamma ray methods based on high purity germanium detectors are most suitable in view of their quasi-ideal combination of high energy resolution, typical of semiconductor materials, and high efficiency curve due to the high atomic number of Ge. Their application, however, is often Limited for practical reasons relating to the need to cool the HPGe crystal to liquid nitrogen temperature during the operation, and to the minimum size of the crystal, which increases the background response of the detector. The investigations carried out with passive implanted planar silicon (PIPS) detectors, presented as a viable alternative to HPGe detectors for same applications, are summarised here. Taking into account the steeper efficiency curve of silicon relative to energy, the quantitative information obtained using silicon prototypes shows which new developments may be most beneficial.

Dosimetry in targeted radiotherapy (TR) uses different calculation methods, whose degree of refinement is closely conditioned by the particular objective sought.It is more generally performed to establish a correlation between the quantity of radiation delivered to a target and the biological damage observed or that can be reliably predicted.It can thus be used to optimise treatments and allow comparison of different therapeutic approaches, as well. as to study the basic methods of irradiation of biological matter.Two broad types of investigations can be found in the literature: microdosimetric ones (stochastic approaches used to study energy deposits) and macrodosimetric ones (non-stochastic or deterministic approaches). The mathematical formalism is consistent between these two types, and the calculation methods currently used are often similar.This review presents different approaches to the dosimetry of radionuclides used in TR.The introduction defines the general problem, the role of dosimetry in TR and the specific problems raised by targeting (non-uniformity of source distributions).The first part considers the types of calculation methods found in TR in relation to the basic quantities used to represent stochastic energy deposit on a cellular scale. In particular, it compares the formalism and the methods used in microdosimetric or conventional macrodosimetric approches. Although microdosimetry, or even track structure calculations, can provide the basic elements for modelling the absorbed dose process, a simplified dosimetric approach may be adequate to describe the phenomena observed. The scheme proposed by the MIRD committee relates to such an approach and is presented together with other methods allowing the calculation of the mean dose delivered (analytic methods, dose point kernels, Monte-Carlo, etc.).The second part shows the application range for the various methods, providing selected examples of dosimetric approaches in TR on different scales, from the organ (or tissues) to the cell or even DNA, and a brief presentation of bone marrow dosimetry.

Measurement systems with the capability of imaging tissues contaminated with radioactive materials would find relevant applications in medical physics research and possibly in health physics. The latter in particular depends critically on the performance achieved for sensitivity and spatial resolution. An original approach of computer assisted collimation gamma camera (French acronym CACAO) which could meet suitable characteristics has been proposed elsewhere. CACAO requires detectors with high spatial resolution The present work was aimed at investigating the application of the CACAO principle on a laboratory testing bench using silicon detectors made of small pixels.

The computer aided collimation gamma camera is aimed at breaking down the resolution sensitivity trade-off of the conventional parallel hole collimator. It uses larger and longer holes, having an added linear movement at the acquisition sequence. A dedicated algorithm including shift and sum, deconvolution, parabolic filtering and rotation is described. Examples of reconstruction are given. This work shows that a simple and fast algorithm, based on a diagonal dominant approximation of the problem can be derived. Its gives a practical solution to the CACAO reconstruction problem.

A silicon drift detector (SDD) prototype where the drift electrode also plays the role of a high-voltage divider has been realised and characterised for spectroscopic applications at near-room temperatures. Among the advantages of this design, is the absence of metal on the sensitive surface which makes this detector interesting for soft X-rays. The detector prototype has a large sensitive area (2 x 130 mm(2)) and the charge is collected by two anodes (butterfly-like detector),The energy resolution of a such a detector has been investigated at near-room temperatures using a commercial, hybrid, low-noise charge-sensitive preamplifier. The results obtained for the X-ray lines from Fe-55 and Am-241 are presented. (C) 2000 Elsevier Science B.V. All rights reserved.

Medical PhysicsVolume 26, Issue 5 p. 848-852 Letters to the editor Response to the Letter to the Editor “Estimating RBEs at clinical doses from microdosimetric spectra” [Med. Phys. 25, 1055 (1998)] P. Pihet, P. Pihet Institut de Protection et de Sûreté Nucléaire, Département de Protection de la santé de l'Homme et de Dosimétrie IPSN, BP n° 6, F 92265 Fontenay-aux-Roses Cedex, FranceSearch for more papers by this authorH. G. Menzel, H. G. Menzel European Commission, Radiation Protection Research Action, DGXII-F6, Mo75 4/21, B-1200 Brussels, BelgiumSearch for more papers by this author P. Pihet, P. Pihet Institut de Protection et de Sûreté Nucléaire, Département de Protection de la santé de l'Homme et de Dosimétrie IPSN, BP n° 6, F 92265 Fontenay-aux-Roses Cedex, FranceSearch for more papers by this authorH. G. Menzel, H. G. Menzel European Commission, Radiation Protection Research Action, DGXII-F6, Mo75 4/21, B-1200 Brussels, BelgiumSearch for more papers by this author First published: 04 May 1999 https://doi.org/10.1118/1.598595Citations: 6AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume26, Issue5May 1999Pages 848-852 RelatedInformation

The design and characteristics of a spectroscopy system prototype, featuring a high energy resolution semiconductor detector operating at room temperature, is presented with a view to its use for solving radiation protection monitoring problems. This device combines large-area (3x3 cm2) strip silicon detectors and discrete analogue electronics including multiplexed readout circuits and anticoincidence shielding. The applications of such a system are discussed in the light of germanium detector technology. Contaminated wounds, thyroid and small biological samples are reviewed as examples of operational cases relevant to individual monitoring.

This study is part of a project aimed at developing a new monitoring system to improve measurements of lung retention for Pu-239. To cover the thoracic volume, the proposed system used silicon detectors operating at room temperature. This report gives the first conclusions of this feasibility study. The results were obtained using a detection module composed of silicon strip detectors. Analogue electronics were specially designed to optimise signal-to-noise ratio and to investigate background by using anticoincidence between the silicon detectors. Overall counting efficiency determination was carried out by scanning the surface of a Livermore phantom. Combining these measurements, the detection limits are discussed for the complete modular system with emphasis on the competition between efficiency and background to demonstrate the innovative feature of such a system as an alternative to germanium detectors systems. The proposed new monitoring system may enable the detection limit for Pu-239 to be lowered by a factor of 2.

Specification of radiation quality is an important issue in fast neutron therapy since the biological effectiveness of the beams varies to a large extent with neutron energy. It must meet specific criteria, mainly derived from the accuracy requirement for absorbed dose delivery. A first approach to this problem consists in identifying physical parameters that can be related to Relative Biological Effectiveness (RBE) and which describe the beam production technique (e.g. neutron-producing reaction, p + Be or d + Be, energy of the incident particle). A second is based on microdosimetry, which provides a description of the secondary radiation components to which the biological consequences of irradiations are more directly correlated. A third approach consists in experimental RBE determinations in reference conditions: intestinal crypt regeneration in mice after irradiation to the whole body with single doses is proposed as a standard biological system for radiobiological calibrations of clinical fast neutron beams. Dosimetric, microdosimetric and radiobiological intercomparisons are encouraged since they provide a homogeneous set of data which facilitate the exchange of clinical information. They also constitute a basis for the clinical RBE approach and an overall check of the irradiation procedure. Therefore they should be recommended in every non-conventional radiation therapy facility.