Capri, THz, 2002 Bernard Veyret PIOM Laboratory College of Chemistry and Physics, Bordeaux Biological Effects in the Microwave, Thz, and Infrared Regions Biological Effects in the Microwave, Thz, and Infrared Regions
Capri, THz, 2002 Frequency Spectrum 1 fm 1 GHz 50/60 Hz static RF THz gap
Capri, THz, 2002 History Microwaves (radars, hyperthermia) Mobile telephony (analog, TDAM, CDMA) Wireless communications
Capri, THz, 2002 Biophysical intercation Biochemical changes Biological effect Health effect
Capri, THz, 2002 Scientific approaches Biological models Dosimetry Biological models Dosimetry animals cells Foundations epidemiology humans
Capri, THz, 2002 Sources of information Databases –WHO EMF project ( IEEE, Information Venture, etc. Reports, Reviews –ICNIRP, WHO, … –‘ McKinlay ’, ‘ Stewart ’, ‘ Zmirou ’ ‘ Health Canada ’, etc. Scientific societies –BEMS, EBEA, URSI, etc.
Capri, THz, 2002 Sources of information Peer-reviewed articles Out of 31,049 refs, only one on THz!
Capri, THz, 2002 WHO database mobile telephony signals Cancer relevant or related completed ongoing total epidemiology bioassays sensitized in vivo acute in vivo in vitro Total
Capri, THz, 2002 WHO database mobile telephony signals Non cancer completed ongoing total epidemiology human acute in vivo in vitro Total
Capri, THz, 2002 WHO database mm waves: 12 references (< 94 GHz) THz and IR: 0 reference
Capri, THz, 2002 Centimetre waves ( > 3 cm) Mechanism: heating Metric: SAR (W/kg) ICNIRP basic restriction: 2 W/kg (10 g) Dosimetry (dielectric properties, numerical simulations, etc.): satisfactory Epidemiology: –Cancer: unconclusive, large study in progress –Symptoms: unconclusive
Capri, THz, 2002 cm waves Humans –Minor alterations of sleep, EEG, etc. –No evidence of hypersensitivity
Capri, THz, 2002 Whole-body exposure system ITIS mice
Capri, THz, 2002 Head-only exposure Loop antenna
Capri, THz, 2002 Head-mainly exposure
Capri, THz, 2002 cm waves Animals –Cancer: negative –Blood-brain-barrier: some evidence > 1 W/kg
Capri, THz, 2002 In vitro: exposure systems Petri dishes 1800 MHz Kuster et al.
Capri, THz, 2002 cm waves Cells –Proliferation: negative –Genotoxicity: negative –Heat shock proteins: positive?
Capri, THz, 2002 Millimetre waves (3 cm > > 3 mm) Basic restriction: irradiance E ICNIRP: 10 W/m 2 Absorption by the skin Initial article from Germany: Grundler, W. and Keilmann, F. (1978) Nonthermal effects of millimeter microwaves on yeast growth. Z Naturforsch [C], 33,
Capri, THz, 2002 mm waves in the FSU Basic research and medical applications Betski ’s school: 10 mW/cm 2 non resonant Sitko ’s school: µW/cm 2 resonant Skin disorders, gastric ulcers, heart disease, and cancer Today, most of the Russian scientists work in Europe and USA
Capri, THz, 2002 mm waves Main review: Pakhomov, Bioelectromagnetics, 19, (1998) Main research groups: Temple University, Philadelphia, and Brooks AF base, TX, USA, Research activity likely to increase in the coming years (R-Lan, radar, etc.)
Capri, THz, 2002 Main target: skin
Capri, THz, 2002 mm waves: cancer Carcinogenesis 2001 Oct;22(10): Lack of effect of 94 GHz radio frequency radiation exposure in an animal model of skin carcinogenesis Mason et al. Brooks, TX, USA 3.33 W/m 2, 10 sec, twice a wk for 12 wks
Capri, THz, 2002 Spectrum of water IR THz
Capri, THz, 2002 THz (3 mm > > 15 µm) ICNIRP: 1000 W/m 2 (1,041 µm to 1 mm, 10 s to 8 h) based on thermal effects on the cornea
Capri, THz, 2002 Far infrared (15 µm > > 3 µm) Few studies besides the thermal effect on the cornea
Capri, THz, 2002 Mechanisms Very low energy of the microwave photon 1 GHz = 4 x eV 1 THz= 4 x eV kT = 3 x eV covalent bond = 3 eV ionisation= 12.5 eV Only well-established mechanisms is heating Other mechanisms are being explored and tested in the laboratory
Capri, THz, 2002 Conclusion Most of the research is done in the cm range because of mobile communications Above 10 GHz, –The skin is the main target –A lot more research is needed for health risk assessment –Exposure systems and biological models are becoming available