Moscow-Bordeaux project RF dosimetry
Abstract
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Oversight the World Health Organisation, a collaborative study between laboratories in France (PIOM, Bordeaux) and Russia (Institute of Biophysics, Moscow) has for objective to confirm the Russian previous results on immunological effects of microwaves. The aim of our project is to control precisely dosimetry and RF exposure system, and to analyse the coupling between electromagnetic waves and whole body exposed animal at 2375 MHz.
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Partners
XLIM – UMR 6172 CNRS
Web site: www.xlim.fr
Official contact
Mr Philippe LEVEQUE
XLIM – CNRS
Duration
12 months
Summary
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1) Introduction
The work presented in a series of Russian and Ukrainian articles dealt mainly with the effects on the immune system of rats exposed to a continuous wave (CW) radiofrequency (RF) electromagnetic field (EMF) at around 2375 MHz (0.1 to 10 W/m²). These bioeffects were observed after long-term low-intensity exposure and in the absence of precise dosimetry, so it was deemed necessary to confirm the Russian results with the help of independent laboratories. In this context, two laboratories in France (PIOM, Bordeaux) and Russia (Institute of Biophysics, Moscow) will replicate the studies on immunological effects of microwaves. XLIM is in charge of the electromagnetic part of these studies, specially the dosimetry of the exposure system used for replications. The expected results are the specific absorption rate (SAR) values induced inside the rats by RF EMF and the measured values of the electrical fields produced by the exposure system. Finally, Russian physicists and biologists will become aware of RF dosimetry problems.
2) State of the art
In vivo studies require optimised methodological approaches to test a hypothesis. The delivery of precise doses of RF EMF into animals is a complex and often underestimated task. The global and locally induced fields or SAR for a defined incident fields strength depend on many extrinsic and intrinsic parameters such as frequency, polarisation, field impedance, animal size, posture, age, sex, humidity, … So good scientific practise requires precise and sufficient data for comparison with similar studies or replications.
3) Scientific methodology
The 2375 MHz exposure system consists of a magnetron generator, a cylindrical horn antenna with elliptic polarisation. The conditions of exposure will simulate an EM plane wave. Sixteen animals are placed in an annular fashion, in plastic cages, with one animal per cage. Animals are free to move.
The dosimetry and especially the assessment of uncertainties and variations will be determined. They require accurate and very effective tools. The anatomy of animals is highly complex, consisting of hundreds of different parts. We will used simulation tools based on the finite-difference time-domain (FDTD) method which are capable of handling such objects. The SAR will be evaluated : whole body, different tissues/organs, averaged and spatial peak values, considering the real exposure conditions.
The incident power density will be measured at the location of the cages in the absence of the animals with the help of a broadband meter (EMR-20/-30, Narda STS, Germany, or equivalent). Such measurements will be carried out at regular intervals and the power of the generator monitored in real time. Overall dosimetry will be determined initially by XLIM as an independent expert and monitored regularly by local experts.
4) Partnership, skills
This study will be made in relation with two laboratories : PIOM (Bordeaux, France) and Institute of Biophysics (Moscow, Russia).