[en] In this report for Accreditation to Supervise Researches (HDR), the author, after his curriculum and an indication of his publications and registered patents, presents his research project. This presentation first comprises works performed for the development of a new instrument aimed at producing real-time images of the position of radioactive medicines which emit low energy β radiation. These works notably resulted in the production of the 'Beaver' instrument, a gaseous detector which notably comprises competitive PIM microstructures (Parallel Ionisation Multiplier). Then, he addresses the direct detection of dark matter with detectors containing Xenon operating in double liquid/gas phase. This detector is particularly interesting for very-low background noise works in the study of dark matter in the Universe, for example through the XENON100 and XENON1T experiments which have been enhanced by the introduction of the ReStoX unit which extends the experiment capacity. The last part addresses the development of 3-photon medical imagery, a new imagery technique at very low dose, in which Xenon plays a key role as it is the active heart of 3-photon cameras. The precise measurement of the ionisation signal is performed with MIMELI detectors which are presented. This builds up a new generation of cameras which can be very useful for nature observation.

[en] Autoradiography is a widely used technique in pharmacology and biological fields. It is able to localize in 2 dimensions molecules labeled with beta emitters. The gaseous detector incorporating micromesh Parallel Ionization Multiplier (PIM) has already shown its ability to localize precisely electrons from low-energy emitters like ³H and ¹⁴C with a high resolution or on a large area. We report on a new prototype devoted to precise determination of beta emitters. It could be used to image gamma emitters distribution by using autoradiography of the associated beta particles present on a large number of useful gamma radioelements such as ¹³¹I, ⁴⁶Sc, ¹⁸F, etc. By proceeding with a dedicated method, we expect to locate in 2 dimensions the position of gamma emitter with a precision greater than 150 μm. This new prototype could also be used for traditional low-energy beta autoradiography of ³H, ¹⁴C or ¹²⁵I with a spatial resolution better than 50 μm and real-time imaging. First results obtained with this new prototype are presented.

[en] Since the seventies, positron emission tomography (PET) has become an invaluable medical molecular imaging modality with an unprecedented sensitivity at the picomolar level, especially for cancer diagnosis and the monitoring of its response to therapy. More recently, its combination with x-ray computed tomography (CT) or magnetic resonance (MR) has added high precision anatomic information in fused PET/CT and PET/MR images, thus compensating for the modest intrinsic spatial resolution of PET. Nevertheless, a number of medical challenges call for further improvements in PET sensitivity. These concern in particular new treatment opportunities in the context personalized (also called precision) medicine, such as the need to dynamically track a small number of cells in cancer immunotherapy or stem cells for tissue repair procedures. A better signal-to-noise ratio (SNR) in the image would allow detecting smaller size tumours together with a better staging of the patients, thus increasing the chances of putting cancer in complete remission. Moreover, there is an increasing demand for reducing the radioactive doses injected to the patients without impairing image quality.

There are three ways to improve PET scanner sensitivity: improving detector efficiency, increasing geometrical acceptance of the imaging device and pushing the timing performance of the detectors. Currently, some pre-localization of the electron-positron annihilation along a line-of-response (LOR) given by the detection of a pair of annihilation photons is provided by the detection of the time difference between the two photons, also known as the time-of-flight (TOF) difference of the photons, whose accuracy is given by the coincidence time resolution (CTR). A CTR of about 10 picoseconds FWHM will ultimately allow to obtain a direct 3D volume representation of the activity distribution of a positron emitting radiopharmaceutical, at the millimetre level, thus introducing a quantum leap in PET imaging and quantification and fostering more frequent use of ¹¹C radiopharmaceuticals.

The present roadmap article toward the advent of 10 ps TOF-PET addresses the status and current/future challenges along the development of TOF-PET with the objective to reach this mythic 10 ps frontier that will open the door to real-time volume imaging virtually without tomographic inversion. The medical impact and prospects to achieve this technological revolution from the detection and image reconstruction point-of-views, together with a few perspectives beyond the TOF-PET application are discussed. (roadmap)

[en] This publication gathers Power Point presentations and texts of contributions to a meeting which notably addressed dark matter and double beta decay without neutrino. The contributions contains activity reports, presentations of works and researches, lists of publications related to different programs, experiments and projects. A report first proposes an introduction of the physics of rare events, and states opinions and recommendations about the various projects and experiments which are then the matter of more detailed presentations (activity reports, presentations of researches, works and results). These projects and experiments are Edelweiss (direct detection of non-Baryonic dark matter), Xenon (direct detection of dark matter with the use of liquid xenon), SUPERNEMO (ultra low background physics experiment with double beta decay search), and several R and D projects such as DAMIC-M (Dark Matter In CCDs at Modane), CENNS/Ricochet (collaborative project on Coherent Elastic Neutrino-Nucleus Scattering), Dark Side (development of a dark matter detector), MIMAC (experimental project for the detection of non-Baryonic dark matter by using an underground matrix of time projection chambers), CROSS and CUPID (search for a crystal for double beta decay without neutrino).

[en] These scientific days were organised by the 'technical protection' Section of the French Society of Radiation Protection (SFRP) in cooperation with the French society of medical physicists (SFPM), the Swiss Romandie association of radioprotection (ARRAD) and the associated laboratories of radio-physics and dosimetry (LARD). The objective of these days was to review the existing calculation codes used in radiation transport, source estimation and dose management, and to identify some future prospects. This document brings together the available presentations (slides) together with their corresponding abstracts (in French) and dealing with: 1 - Presentation of the conference days (L. De Carlan); 2 - Simulating radionuclide transfers in the environment: what calculation codes and for what? (C. Mourlon); 3 - Contribution of Monte-Carlo calculation to the theoretical foundation analysis of calibration procedures and dosemeters design for radioprotection photon dosimetry (J.M. Bordy); 4 - Use of calculation codes in R and D for the development of a new passive dosemeter for photons and beta radiations (B. Moreno); 5 - Development of a new virtual sources model for the Monte-Carlo prediction of EPID (Electronic Portal Imaging Device) images and implementation in PENELOPE (I. Chabert); 6 - Prediction of high-resolution EPID images for in-vivo dosimetry (D. Patin); 7 - 4D thorax modeling by artificial neural networks (P.E. Leni); 8 - Presentation of the calculation utilities of the book 'Calculation of ionizing radiations generated doses' (Vivier, Lopez, EDP Sciences 2012) (A. Vivier); 9 - RayXpert^C: a 3D modeling and Monte-Carlo dose rate calculation software (C. Dossat); 10 - TRIPOLI-4^R Version 9 S Monte-Carlo code for radioprotection (F. Damian); 11 - Realistic radioprotection training with the digital school workshop (E. Courageot); 12 - Use of BEAMNRC code for dental prostheses influence evaluation in ENT cancers treatment by external radiotherapy (C. De Conto); 13 - Calculation of secondary doses received by healthy tissues of patients treated by proton-therapy for eye or intracranial tumors (J. Farah); 14 - Use of FLUKA at the design stage of the installation of a X-Ray production facility: THOMX project (J.M. Horodynski); 15 - Shielding study using FLUKA for the construction of a new experimental zone for the N-TOF facility at CERN (J. Vollaire); 16 - Radioprotection studies optimisation for the dimensioning of radioactive materials storage and transport packagings (C. Nicoletti); 17 - Source terms calculation using ALEPH2 (A. Stankovskiy); 18 - Organs dose calculation in scanography (S. Dreuil); 19 - Calculation of beta spectra shape (X. Mougeot); 20 - Implementation of a DNA geometry in GEANT4-DNA Monte-Carlo calculations for radio-induced damages analysis (C. Villagrasa); 21 - Treatment planning optimization in nuclear medicine by personalized Monte-Carlo dosimetry: application to selective internal radiotherapy (SIRT) (A. Petitguillaume); 22 - Comparison between two personalized dosimetry approaches at the voxel scale for yttrium-90 radio-embolization (S. Gnesin); 23 - Criticality accident - Codac and dose assessment (A. Thomassin); 24 - Monte-Carlo calculations about the angular and energy dependence of the efficient dose for low energy photon beams and the impact of leaded clothing use (C. Saldarriaga Vargas); 25 - Study of Xenon-133 external exposure for the overall operating NPPs (A. Perier); 26 - Monte-Carlo codes intercomparison exercise for the modelling of a medical linear accelerator (M. Le Roy); 27 - Automatic determination of the primary electron beam parameters in Monte-Carlo simulations of linear accelerators for radiotherapy (D. Lazaro); 28 - Monte-Carlo determination of collimator opening and correction factors for a CyberKnife 1000 UM/min fitted with fixed collimators (C. Moignier, Presentation not available); 29 - Rooms investigation and characterization prior to dismantling - Coupling between a transport code and a geo-static code (Y. Desnoyers, G. Juhel); 30 - Dimensioning and optimization of thick heterogeneous protections using MCNP5 Monte-Carlo code (C. Mattera)