Capri, THz, 2002 Bernard Veyret PIOM Laboratory College of Chemistry and Physics, Bordeaux...
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Capri, THz, 2002
Bernard VeyretPIOM 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 SpectrumFrequency SpectrumFrequency SpectrumFrequency Spectrum
1 GHz50/60 Hz
static RF
THz gap
Capri, THz, 2002
HistoryHistory
• Microwaves (radars, hyperthermia)
• Mobile telephony (analog, TDAM, CDMA)
• Wireless communications
Capri, THz, 2002
Biophysicalintercation
Biochemical changes
Biological effect
Health effect
Capri, THz, 2002
Scientific approachesScientific approaches
Biological modelsDosimetry
Biological modelsDosimetry
animalsanimals
cellscells
FoundationsFoundations
epidemiologyepidemiology
humanshumans
Capri, THz, 2002
Sources of informationSources of information• Databases
– WHO EMF project (www.who.int/peh-emf/), 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 informationSources of information
• Peer-reviewed articles
Out of 31,049 refs, only one on THz!
Capri, THz, 2002
WHO database mobile telephony signals
WHO database mobile telephony signals
• Cancer relevant or related• completed ongoing total
epidemiology 8 18 26bioassays 6 8 14sensitized in vivo 11 7 18acute in vivo 22 5 27in vitro 50 26 76Total 97 64 161
Capri, THz, 2002
WHO databasemobile telephony signals
WHO databasemobile telephony signals
• Non cancer• completed ongoing total
epidemiology 4 0 4human 45 21 66acute in vivo 32 10 42in vitro 15 10 25Total 96 41 137
Capri, THz, 2002
WHO databaseWHO database
• mm waves: 12 references (< 94 GHz)
• THz and IR: 0 reference
Capri, THz, 2002
Centimetre waves ( > 3 cm)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 wavescm waves
• Humans– Minor alterations of sleep, EEG, etc.– No evidence of hypersensitivity
Capri, THz, 2002
Whole-body exposure systemWhole-body exposure system
ITIS
mice
Capri, THz, 2002
Head-only exposureHead-only exposure
Loop antenna
Capri, THz, 2002
Head-mainly exposureHead-mainly exposure
Capri, THz, 2002
cm wavescm waves
• Animals – Cancer: negative– Blood-brain-barrier: some evidence > 1 W/kg
Capri, THz, 2002
In vitro: exposure systemsIn vitro: exposure systems
Petri dishes
1800 MHz
Kuster et al.
Capri, THz, 2002
cm wavescm waves
• Cells– Proliferation: negative– Genotoxicity: negative– Heat shock proteins: positive?
Capri, THz, 2002
Millimetre waves (3 cm > > 3 mm)Millimetre waves (3 cm > > 3 mm)
• Basic restriction: irradiance E ICNIRP: 10 W/m2
• 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, 15-22.
Capri, THz, 2002
mm waves in the FSUmm waves in the FSU
• Basic research and medical applications
• Betski ’s school: 10 mW/cm2 non resonant
• Sitko ’s school: µW/cm2 resonant
• Skin disorders, gastric ulcers, heart disease, and cancer
• Today, most of the Russian scientists work in Europe and USA
Capri, THz, 2002
mm wavesmm waves
• Main review: Pakhomov, Bioelectromagnetics, 19, 393-413 (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: skinMain target: skin
Capri, THz, 2002
mm waves: cancermm waves: cancer
• Carcinogenesis 2001 Oct;22(10):1701-8
• 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/m2, 10 sec, twice a wk for 12 wks
Capri, THz, 2002
Spectrum of waterSpectrum of water
IR THz
Capri, THz, 2002
THz (3 mm > > 15 µm)THz (3 mm > > 15 µm)
• ICNIRP: 1000 W/m2 (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)Far infrared (15 µm > > 3 µm)
• Few studies besides the thermal effect on the cornea
Capri, THz, 2002
MechanismsMechanisms• Very low energy of the microwave photon
1 GHz = 4 x 10-6 eV 1 THz = 4 x 10-3 eVkT = 3 x 10-2 eV
covalent bond = 3 eVionisation = 12.5 eV
• Only well-established mechanisms is heating
• Other mechanisms are being explored and tested in
the laboratory
Capri, THz, 2002
ConclusionConclusion
• 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