[en] Solving the problem of traceability of the absorbed dose to the tumour for the radiation fields of small and very small dimensions, like those used for new treatment modality usually results in the use of dosemeters of much smaller size than those of the beam. For the realisation of the reference in primary standards laboratories, the absence of technology likely to produce absolute small-size dosemeters leaves no possibility for the direct measurement of the absorbed dose at a point and implies the use of passive or active small-size transfer dosemeters. This report intends to introduce a new kind of dose quantity for radiotherapy similar do the Dose Area Product concept used in radiology. Such a new concept has to be propagated through the metrology chain, including the TPS, to the calculation of the absorbed dose to the tumour. (authors)

[en] This study is part of a project aimed at developing a new monitoring system to improve measurements of lung retention for ²³⁹Pu. To cover the thoracic volume, the proposed system uses 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 ²³⁹Pu to be lowered by a factor of 2. (author)

[en] Within the frame of the CONRAD European project (Coordination Network for Radiation Dosimetry), and more precisely within a work group paying attention to uncertainty assessment in computational dosimetry and aiming at comparing different approaches, the authors report the simulation of an irradiator containing a caesium 137 source to calculate the kerma in air as well as its uncertainty due to different parameters. They present the problem geometry, recall the studied issues (kerma uncertainty, influence of capsule source, influence of the collimator, influence of the air volume surrounding the source). They indicate the codes which have been used (MNCP, Fluka, Penelope, etc.) and discuss the obtained results for the first issue

[en] Within the framework of the European project CONRAD (Coordinated Network for Radiation Dosimetry, contract FP6-12684) coordinated by EURADOS (European Radiation Dosimetry group), WP4 was devoted to numerical dosimetry under the title 'Uncertainty assessment in computational dosimetry: an intercomparison of approaches'. Within this activity, a working group sent a list of eight exercises, dealing with radiation transport of photons, neutrons, protons and electrons, to be solved by the international community. This paper presents exercise number 4, dealing with the calculation of air kerma for a ¹³⁷Cs beam. This problem was aimed at estimating the components of the uncertainty on the air kerma which cannot be measured, namely those due to geometrical data such as the source location, the diameter of the collimator, the material density, etc. 12 institutes of 10 different countries took part in this work, showing the interest in this proposal. (authors)

[en] The purpose of this work is to present an innovative approach for the creation and application of voxel phantoms associated with the Monte Carlo calculation (MCNP) for the calibration of whole-body counting systems dedicated to the measurement of fission and activation products. The new method is based on a graphical user interface called 'OEDIPE' that allows to simulate a whole measurement process using all measurement parameters, the final goal being to approach a numerical calibration of the facilities. The creation of voxel phantoms and validation of the method are presented in this paper using the IGOR phantom. Finally, the efficiency of the method is discussed, in particular, with the perspective of validating IGOR as a suitable human-equivalent phantom and for the assessment of uncertainties in dose estimation due to the inhomogeneous distribution of activity in the body, correlated to the bio-kinetic behaviour of the radionuclides. (authors)

[en] LNE-LNHB is involved in a European project aiming at establishing absorbed dose-to-water standards for photon-radiation fields down to 2 x 2 cm². This requires the calibration of reference ionization chambers of small volume. Twenty-four ionization chambers of eight different types with volume ranging from 0.007 to 0.057 cm³ were tested in a ⁶⁰Co beam. For each chamber, two major characteristics were investigated: (1) the stability of the measured current as a function of the irradiation time under continuous irradiation. At LNE-LNHB, the variation of the current should be less than ±0.1% in comparison with its first value (over a 16 h irradiation time); (2) the variation of the ionization current with the applied polarizing voltage and polarity. Leakage currents were also measured. Results show that (1) every tested PTW (31015, 31016 and 31014) and Exradin A1SL chambers demonstrate a satisfying stability under irradiation. Other types of chambers have a stability complying with the stability criterion for some or none of them. (2) IBA CC01, IBA CC04 and Exradin A1SL show a proper response as a function of applied voltage for both polarities. PTW, Exradin A14SL and Exradin A16 do not. Only three types of chambers were deemed suitable as reference chambers according to LNE-LNHB requirements and specifications from McEwen (2010 Med. Phys. 37 2179-93): Exradin A1SL chambers (3/3), IBA CC04 (2/3) and IBA CC01 (1/3). The Exradin A1SL type with an applied polarizing voltage of 150 V was chosen as an LNE-LNHB reference chamber type in 2 x 2 cm² radiation fields.

[en] New bio-metric equations used for assessing the thickness of the overlay plate to be added to the physical phantom were determined based on the Computed Tomography (CT) chest images of 33 adult males in order to improve the calibration of in vivo lung counting systems using the Livermore phantom. These equations are specific to systems composed of four germanium detectors with the measured subject in supine position. A comparison with the bio-metric equations used to date as reference in France was carried out and proved the usefulness of equations directly applicable to the Livermore phantom. (authors)

[en] For monitoring internal exposure, detector systems with sufficiently low detection limits to measure intakes of ²³⁹Pu in lung at low level are missing although much progress has been made in whole-body counting systems equipped with high purity germanium detectors. Passivated implanted silicon detectors can provide an alternative by associating the advantage of high resolution, planar geometry and room temperature operation. The last in particular, would lead to higher flexibility compared with germanium detectors and allow the building of arrays of such detectors to achieve larger total detection areas with more realistic geometry. The paper shows the potential of this approach towards the practical solution of lung monitoring problems for radiological protection in the nuclear fuel processing industry. (Author)

[en] A multichannel OSL Fibre Optic dosimeter based on Optically Stimulated Luminescence (OSL) of alumina is proposed for on-line In Vivo Dosimetry (IVD) in Radiation Therapy (RT). Two types of dosimetric-grade Al₂O₃:C crystals are compared and show different behavior according to manufacturing process. Metrological validations have been performed with a Saturne 43 LINAC in reference conditions at CEA LIST LNHB (French Ionizing Radiation Reference Laboratory). The dose response of OSL integrals under photon beam irradiation (6, 12 and 20 MV) show sub-linearity behavior modeled by second-order equations and exhibit a small energy dependence (between 0.7% and 1.4%), explained by a modified intermediate cavity model adapted to a Linac photon spectrum. Preclinical tests at Institut Gustave Roussy (IGR) prove that a proper design for a PMMA build-up cap leads to a low dependence vs photon beam orientation (± 1.5% and ± 0.9 %) and vs field size in view of surface measurements. (authors)

[en] This document gathers the slides of the available presentations given during these conference days. Twenty seven presentations are assembled in the document and deal with: 1 - GATE: calculation code for medical imaging, radiotherapy and dosimetry (S. Jan); 2 - estimation of conversion factors for the measurement of the ambient dose equivalent rate by in-situ spectroscopy (J.P. Laedermann); 3 - geometry specific calibration factors for nuclear medicine activity meters (F. Bochud); 4 - Monte Carlo simulation of a rare gases measurement system - calculation and validation, ASGA/VGM system (A. Ferragut); 5 - design of a realistic radiation field for the calibration of the dosemeters used in interventional radiology/cardiology (medical personnel dosimetry) (J.M. Bordy); 6 - determination of the position and height of the KALINA facility chimney at CEA Cadarache (L.L. Parisi); 7 - MERCURAD^TM - 3D simulation software for dose rates calculation (R. Abou-Khalil); 8 - PANTHERE - 3D software for gamma dose rates simulation of complex nuclear facilities (M. Longeot); 9 - radioprotection, from the design to the exploitation of radioactive materials transportation containers (S. Kitsos); 10 - post-simulation processing of MCNPX responses in neutron spectroscopy (J.E. Groetz); 11 - last developments of the Geant4 Monte Carlo code for trace amounts simulation in liquid water at the molecular scale (C. Villagrasa); 12 - Calculation of H_p(3)/K_air conversion coefficients using PENELOPE Monte-Carlo code and comparison with MCNP calculation results (J. Daures); 13 - artificial neural networks, a new alternative to Monte Carlo calculations for radiotherapy (E. Martin); 14 - use of case-based reasoning for the reconstruction and handling of voxelized fantoms (J. Henriet); 15 - resolution of the radioactive decay inverse problem for dose calculation in radioprotection (A. Tsilanizara); 16 - use of NURBS-type fantoms for the study of the morphological factors influencing the pulmonary anthropo-radiometry (J. Farah); 17 - evaluation of the GUINEVERE experiment shielding (W. Uyttenhove); 18 - GATE/GEANT4 validation for external radiotherapy (Y. Perrot); 19 - European intercomparison of Monte Carlo code users for the kerma uncertainty calculation in air near a ¹³⁷Cs source (L. De Carlan); 20 - decision threshold and detection limit in gamma dose rate measurement (A. Vivier); 21 - uncertainties spreading from basic data of nuclear reactors key parameters (I. Kodeli); 22 - evaluation of secondary neutrons-related doses received by patients treated by proton-therapy (R. Sayah); 23 - radioprotection optimization for nuclear medicine patients: doses evaluation for the new reference voxelized fantoms of the CIPR (international commission of radiological protection) (L. Hadid); 24 - radiological accident reconstruction using numerical tools: towards a more and more realistic representation of the victim (E. Courageot); 25 - new tools for treatment optimization after internal contamination by Pu/Am/Cm (P. Fritsch); 26 - development of an expert system for the consideration of uncertainties in internal contamination monitoring (E. Davesne); 27 - CUTADOSE, a calculation code for skin dose estimation after skin contamination (X. Michel). (J.S.)