Table of contents :

• electromagnetic radiations (EMR).
• light amplification by stimulated emission of radiation (LASER) : a device which transforms light of various frequencies into an extremely intense, small, and nearly nondivergent beam of monochromatic radiation in the visible region with all the waves in phase. Capable of mobilizing immense heat and power when focused at close range, it is used as a tool in surgical procedures, in diagnosis, and in physiologic studies. With proper equipment, any EMR can made to operate like a LASER :
• microwave amplification by Stimulated Emission of Radiation (MASER)
Web resources : Laser Fundamentals
Pathogenesis : chemists already knew that magnetic fields can affect certain chemical reactions involving radicals, molecules that contain unpaired electrons. But these reactions rely on molecules not found in living creatures. The question remained whether such magnetic-field effects occur in real biological systems. A mutant strain of the bacterium Rhodobacter sphaeroides called R-26 lacking a protective chemical known as a carotenoid that normally soaks up damaging radicals:
• nonionizing radiations (NIR) (n < 3,000 THz ; E < 10 eV)
• radiofrequencies (RF) is the name given to that section of the electromagnetic spectrum from frequencies of 300 kHz to 300 GHz => radiofrequency electromagnetic fields (RFEMF). Frequencies in the THz range (THz = 1012 Hz) are difficult to measure directly (they can be measured by heterodyning: observing the difference frequencies they make with reference signals).

Classification systems :
• divided into bands whose wavelengths and frequencies begin and end on metres times a power of 10. Because the speed of light is close to 3 ^.10⁸ m/s, when these bands are expressed in frequencies, their limits are 3 times a power of 10 Hz
• bands allotted for specific types of communication.
Subdivision :
• radiowaves
• super low and extra low frequency (ELF) => extremely low frequency electromagnetic fields (ELF-MF / ELF-EMF) (0 Hz < n < 300 Hz)

Sources : electricity authorities power lines (50 < n < 60 Hz)
Biological effects :
• cell damage
• considerable long-term exposure to 50-Hz EM fields among nonsmoking power linesmen is associated with a slight increase in lymphocytes with chromatid-type breaks, expecially among those power linesmen who had worked earlier in their life^ref
• synergism
• cells exposed to both ionizing radiation and 60 Hz magnetic fields demonstrated an enhanced frequency of near tetraploid chromosome complements, a feature not observed following exposure to only ionizing radiation^ref
• cancers :
• residential magnetic field exposures commonly experienced by US women do not influence risk of breast cancer^ref
• childhood leukemia
• risk of acute lymphoblastic leukemia (ALL) in children 0-9 years of age whose mothers were exposed to the highest occupational levels of ELF-MF during pregnancy^ref. Studies with aneuploid cell lines raised the hypothesis that ELF EMF may act as a coleukaemogen by compromising DNA damage response to genotoxic agents such as ionising radiation^ref.
• various studies observed an increased risk for tumours in the hematopoietic and lymphatic tissue of people living in the proximity of TV and radio broadcast transmitters. However, methodological limitations to these studies have been identified and their findings are controversial.
• exposure of human peripheral blood mononuclear cells to extremely low frequency pulsed electromagnetic fields (PEMFs) increased both the spontaneous and the PHA- and TPA-induced production of IL-1 and IL-6^ref.
• childhood exposure to residential contact currents may play a role in explaining any possible association between residential magnetic fields and childhood leukemia
• CNS alterations :
• significant 5-HT increase at birth, 15 and 21 days, in the cerebral cortex of growing rats exposed during pregnancy^ref
• increased risk of
• Alzheimer's disease (AD) (RR up to 4 among welders and other workers occupationally exposed to ELF-MF^ref; long-term exposure >=0.2 mT in lifetime principal job leads to a multivariate-adjusted relative risks of 2.3 for AD and 2.0 for dementia. Similar patterns were not seen in women, which may in part be the result of a greater exposure misclassification in women than in men. A similar sex-specific pattern was seen for the associations with average ELF-MF exposure throughout the work life. A dose-response relation was suggested in men, with multivariate-adjusted relative risks of 2.4 for AD and 2.5 for dementia for the upper tertile of lifetime average exposure^ref)
• amyotrophic lateral sclerosis (ALS) (RR up to 2.2 among welders and other workers occupationally exposed to ELF-MF.
• teratogenicity :
• IVF-derived mouse embryos are more sensitive than NB-generated embryos to ELF-MF, and that this sensitivity occurs earlier in development^ref
• the human auditory response to pulses of radiofrequency (RF) energy, commonly called RF hearing, is a well established phenomenon. RF induced sounds can be characterized as low intensity sounds because, in general, a quiet environment is required for the auditory response. The sound is similar to other common sounds such as a click, buzz, hiss, knock, or chirp. Effective radiofrequencies range from 2.4 to 10 000 MHz, but an individual's ability to hear RF induced sounds is dependent upon high frequency acoustic hearing in the kHz range above about 5 kHz. The site of conversion of RF energy to acoustic energy is within or peripheral to the cochlea, and once the cochlea is stimulated, the detection of RF induced sounds in humans and RF induced auditory responses in animals is similar to acoustic sound detection. The fundamental frequency of RF induced sounds is independent of the frequency of the radiowaves but dependent upon head dimensions. The auditory response has been shown to be dependent upon the energy in a single pulse and not on average power density. The weight of evidence of the results of human, animal, and modeling studies supports the thermoelastic expansion theory as the explanation for the RF hearing phenomenon. RF induced sounds involve the perception via bone conduction of thermally generated sound transients, that is, audible sounds are produced by rapid thermal expansion resulting from a calculated temperature rise of only 5 x 10^-6 °C in tissue at the threshold level due to absorption of the energy in the RF pulse. The hearing of RF induced sounds at exposure levels many orders of magnitude greater than the hearing threshold is considered to be a biological effect without an accompanying health effect. This conclusion is supported by a comparison of pressure induced in the body by RF pulses to pressure associated with hazardous acoustic energy and clinical ultrasound procedures.
• ultra low frequency (ULF) (300 Hz < n < 3 kHz) : electromagnetic waves in this range are not strongly absorbed by water or the earth. They may therefore be used to communicate with submarines and with mines. The wavelengths are so long that antennae may be huge. One disadvantage is that, with such low frequency, one can only modulate their amplitude or frequency very slowly (eg with morse code) so they cannot carry much information. This is not a disadvantage if only the phase is required, as is the case for

Sources : navigation systems
• very low frequency (VLF) (3 < n < 30 kHz; l > 10 km) : again, the information carrying capacity is limited.

Sources : navigation systems.
• low frequency (LF) (30 < n < 300 kHz; 1 < l < 10 km) : this band has the advantage that it can propagate around the Earth, by refraction and reflection at the ionisphere or the surface of the Earth itself. Indeed, these 2 conductors form a waveguide for waves in this range, which can therefore be used to communicate across the oceans and around the world.

Sources : radioamateur stations
• medium frequency (MF) (300 kHz < n < 3 MHz; 0.1 < l < 1 km) : these waves are not so well reflected/refracted by the ionosphere, but at night there is enough reflection that one can pick up radio stations hundreds or thousands of km away

Sources : Amplitude Modulated (AM) radio band (535 kHz - 1.605 MHz (200 < l < 600 m)). The frequencies 30-535 kHz are used for maritime communication and navigation and for aircraft navigation. Carrier frequencies of 540 to 1600 kHz are assigned at 10 kHz intervals. You do not need an antenna that has a comparable length, although the strength of the signal will increase as you increase the antenna length.
• high frequency (HF) (3 < n < 30 MHz; 10 < l < 100 m) : as the frequency of the carrier wave increases, it becomes possible to encode more information and to crowd channels (proportionately) closer together.

Sources :
• short waves : 1.605 < n < 54 MHz (5.55 < l < 187 m)
• 1,605 kHz - 30 MHz : amateur radio, government radio, international shortwave broadcast, fixed and mobile communications.
• 30-50 MHz  : government and non-government, fixed and mobile. Includes police, fire, forestry, highway, and railroad services.
• 50-54 MHz : amateur
• citizens band (CB) radio : several bands around 27 MHz.
• channels used for radio control
• very high frequency (VHF) (30 < n < 300 MHz; 1 < l < 10 m) : you need an unobstructed path to the transmitter that is not much different from a straight line. Antennae are often made to be about one quarter or one half wavelength long.

Sources :
• frequency modulation (FM) radio (88 - 108 MHz) : the wavelength are about 3 metres, so simple antennae should be about 1/4 or 1/2 this length.
• television (several different bands between 54 and 220 MHz) : television carries more information than radio does--pictures plus sound-- and so needs broader bands for each channel
The carrier frequencies for VHF television Channels 2-4 cover the frequency range 54 to 72 MHz. There is a band from 72-76 MHz which is reserved for government and non-government services, including a standard aeronautical beacon at 75 MHz. VHF TV channels 5 and 6 are between 76 and 88 MHz. The FM radio band is from 88 to 108 MHz between VHF television Channels 6 and 7.Above the FM is a range 108-122 MHz for aeronautical navigation including localizers, radio ranging and airport control. From 122 to 174 MHz is another general service band for both government and non-government signals. It includes fixed and mobile units and amateur broadcast. Channels 7 through 13 span the frequency range 174-216 MHz. 216-470 MHz includes a number of fixed and mobile communication modes, including some aeronautical navigation and citizens radio. 470-890 MHz includes UHF television channels 14 to 83. Frequencies 890-3000 MHz include a variety of aeronautical and amateur uses, studio-transmitter relays, etc. There are radar bands 1,300-1,600 MHz. The FM stations are assigned center frequencies at 200 kHz separation starting at 88.1 MHz, for a maximum of 100 stations. These FM stations have a 75 kHz maximum deviation from the center frequency, which leaves 25 kHz upper and lower "gaurd bands" to minimize interaction with the adjacent frequency band. Television channels have 5 MHz separation.
Biological effects : the weight of evidence available indicates that, for a variety of frequencies and modulations with both short and long exposure times, at exposure levels that do not (or in some instances do) heat the biological sample such that there is a measurable increase in temperature, RF exposure does not induce DNA strand breaks,  chromosome aberrations, sister chromatid exchanges (SCEs), DNA repair synthesis, phenotypic mutation, or transformation. While there is limited experimental evidence that RF exposure induces micronuclei formation, there is abundant evidence that it does not. There is some evidence that RF exposure does not induce DNA excision repair, suggesting the absence of base damage. There is also evidence that RF exposure does not inhibit excision repair after the induction of thymine dimers by UV exposure, as well as evidence that indicates that RF is not a co-carcinogen or a tumor promoter. Teratologic effects can occur only from exposure levels that cause biologically detrimental increases in body temperature.
Medical applications : radiofrequency ablation (RFA)
• microwaves (MW) => high frequency electromagnetic fields (HF-EMF) (300 MHz < n <  300 GHz ; 1 mm < l < 1 m. Some consider microwaves those with 800 MHz < n < 300 GHz and 37.5 cm < l < 1 m. The term "microwaves" can be misleading as the shortest wavelength is 1 millimeter not 1 "micro" meter)
• ultra high frequency (UHF) (300 MHz < n < 3 GHz; 10 < l < 100 cm)

Sources :
• radio and television broadcast antennas :
• satellite communications (L-band : 390-1550 MHz)
• global positioning system (GPS) : 1.2 -1.6 GHz
• cellular or mobile phones (CP) : MW are made by a transmitter chip and an antenna
• analogue cellular technologies
• C-450, C-Netz , and Nordic Mobile Telephones/450 (NMT450) : 450 MHz
• advanced mobile phone system (AMPS) and narrowband AMPS (N-AMPS) : 800 MHz
• Nordic Mobile Telephones/900 (NMT900), NMT France (NMT-F) and total access communications system (TACS) / Japan access communication system (JTAC) : 900 MHz
• digital cellular technologies
• UltraPhone 110 : 350-500 MHz
• digital AMPS (D-AMPS) : 824-849 and 869-894 MHz
• wireless application protocol (WAP)
• internet protocol (IP)
• IS-54, IS-95 : 800 MHz
• global system for mobile (GSM : the original acronym standed for Groupe Spécial Mobile) communication phones (900 MHz)
• GSM corldless telephone system (CTS). In the home environment, GSM-CTS phones communicate with a CTS Home Base Station (HBS), which offers perfect indoor radio coverage. The CTS-HBS hooks up to the fixed network and offers the best of the fixed and mobile worldsTelecentre-H : 350-500 MHz and 800-1000 MHz
• personal digital cellular (PDC) : 800 and 1500 MHz
• iDEN® (Integrated Digital Enhanced Network) : 800 MHz, 900 Mhz and 1.5 GHz bands
• digital cordless standard (DCS) / GSM1800 / E-Netz (1800 MHz)
• JS-008 : CDMA based standard for 1,900 MHz.
• universal mobile telecommunication system (UMTS) : 2 GHz
• Zigbee UWB Standard : 2.4 GHz
Biological effects :
• 900 MHz
• CNS alterations :
• a 'Phantom Scalp' was constructed from a conducting foam mat to form a layer under a 62-electrode EEG cap closely approximating the electrical properties of a human scalp. The mat was placed over a polystyrene manikin head to preserve a correct anatomical arrangement. Electrical signals were recorded with a GSM communications mobile phone handset in place against the side of the 'head'. Amplitude spectra were compared for 3 phone conditions: 'off', 'standby' and 'transmit'. At 217 Hz, significant differences were obtained between 'transmit' and the other 2 conditions, but no significant differences were noted for the physiologically important range 0.5-30 Hz. An anomalous difference was noted for one electrode in the range 30-45 Hz^ref
• traditional EEG was full of noises during operation of a cellular phone. Using a 16-channel telemetric electroencephalograph (Expert^TM) in awake subjects, all the noise was eliminated, and EEG showed interesting changes: after a period of 10-15 s there was no visible change, the spectrum median frequency increased in areas close to antenna; after 20-40 s, a slow-wave activity (2.5-6.0 Hz) appeared in the contralateral frontal and temporal areas. These slow waves lasting for about one second repeated every 15-20 s at the same recording electrodes. After turning off the mobile phone, slow-wave activity progressively disappeared; local changes such as increased median frequency decreased and disappeared after 15-20 min. We observed similar changes in children, but the slow-waves with higher amplitude appeared earlier in children (10-20 s) than adults, and their frequency was lower (1.0-2.5 Hz) with longer duration and shorter intervals^ref
• 30 min mobile phone use has no short-term adverse effects on the human auditory system as assessed with auditory brainstem response (ABR), the ABR recovery function and middle latency response (MLR)^ref
• attention functions may be differentially enhanced after exposing to the electromagnetic field emitted by mobile phones. Furthermore, this transient facilitation effect might be dose dependent^ref
• human peripheral blood lymphocytes (PBLs)
• no statistically significant differences were detected in terms of either human PBLs micronucleus frequency (evaluated by applying the cytokinesis-block micronucleus assay) or cell cycle kinetics in continuous-wave (CW) intermittent exposure (SAR = 1.6 W/kg) for 6 min followed by a 3-h pause (14 on/off cycles) or Global System of Mobile Communication (GSM) modulated signal, intermittent exposure as described above or GSM signal, intermittent exposure as described above 24 h before stimulation with PHA (8 on/off cycles) or GSM signal, intermittent exposure (SAR = 0.2 W/kg) 1 h per day for 3 days^{ref (8/2003)}
• a linear increase in chromosome 17 aneuploidy was observed as a function of the SAR value after in vitro exposure of human PBLs to continuous 830 MHz electromagnetic fields, demonstrating that this radiation has a genotoxic effect. The SAR dependent aneuploidy was accompanied by an abnormal mode of replication of the chromosome 17 region engaged in segregation (repetitive DNA arrays associated with the centromere), suggesting that epigenetic alterations are involved in the SAR dependent genetic toxicity. Control experiments (i.e., without any RF radiation) carried out in the temperature range of 34.5-38.5 degrees C showed that elevated temperature is not associated with either the genetic or epigenetic alterations observed following RF radiation-the increased levels of aneuploidy and the modification in replication of the centromeric DNA arrays. These findings indicate that the genotoxic effect of the electromagnetic radiation is elicited via a non-thermal pathway^{ref (2/2003), comment1, comment2}.
• tumors
• REFLEX study, a 4-year project performed by 12 research groups in 7 European countries and led by Franz Adlkofer of Verum Foundation, a research organization based in Munich, Germany found that levels of radiation equivalent to those from a phone prompted breaks in individual strands of DNA in a variety of human cells, types of damage have been linked with cancer. The level of injury increased with the intensity of radiation and the length of exposure. Hints, but not conclusive evidence, were found for other cell changes, including damage to chromosomes, alterations in the activity of certain genes and a boosted rate of cell division. The damaging effects occurred when cells were exposed to EMR of intensities 0.3-2 W/kg, overlapping with the level of radiation typically emitted by phones of around 0.2-1 W/kg. Other research groups might have missed equivalent harm in their studies because they exposed cells to radiation for too short a time or used laboratory cell types that are resistant to damage. There is a need for more extensive studies to test whether mobile phone radiation damages DNA in people, and whether this is linked to disease. Until then, users should keep their time on the phone to a minimum and use headsets if they are concerned about the risks.
• chronic exposure to 835.62 MHz FDMA or 847.74 MHz CDMA RF radiation had no significant effect on the incidence of spontaneous tumors in F344 rats^ref
• incidence rates for malignancies arising in the head and neck, including those sites that hypothetically receive the highest levels of radio frequency radiation during cellular telephone use, have not changed materially since the introduction of cellular telephones to New Zealand in 1987 to 2003^ref. In studies of a possible association between brain tumours and mobile phone use, the average period mobile phones use was short compared to the known latency period of brain tumours. Although these studies did not establish an overall increased risk of brain tumours associated with mobile phone use, there were some indications of an association. Immediate effects associated with mobile phone use have been observed in human experimental studies that cannot be explained by conventional thermal mechanisms. In total use of analogue cellular telephones gives an increased risk for brain tumours with OR=1.3, whereas digital and cordless phones do not overall increase the risk significantly. Ipsilateral use of analogue phones gives OR=1.7, digital phones OR=1.3 and cordless phones OR=1.2. The risk for ipsilateral use is significantly increased for astrocytoma for all studied phone types, analogue phones OR=1.8, digital phones OR=1.8, cordless phones OR=1.8. Use of a telephone on the opposite side of the brain is not associated with a significantly increased risk for brain tumours. Regarding anatomical area of the tumour and exposure to microwaves, the risk is increased for tumours located in the temporal area on the same side of the brain that is used during phone calls, significantly so for analogue cellular telephones OR=2.3. For acoustic neurinoma OR=4.4 is calculated among analogue cellular telephone users. When duration of use is analysed as a continuous variable in the total material, the risk increased per year for analogue phones with OR=1.04. For astrocytoma and ipsilateral use the trend was for analogue phones OR=1.10, digital phones OR=1.11, and cordless phones OR=1.09. There was a tendency of a shorter tumour induction period for ipsilateral exposure to microwaves than for contralateral, which may indicate a tumour promotor effect^ref. An increased odds ratio of 3.45, 95% confidence interval (CI) 1.77-6.76, was found for vestibular schwannoma (VS) associated with the use of analogue cell phones. During the time period 1960-1998, the age-standardized incidence of VS in Sweden significantly increased yearly by +2.53%. A significant increase in the incidence of VS was only found for the latter of the two time periods 1960-1979 and 1980-1998. For all other brain tumors taken together, the incidence significantly increased yearly by +0.80% for the time period 1960-1998, although the increase was only significant for benign tumors other than VS during 1960-1979^ref. In Denmark (106 acoustic neuroma patients and 212 healthy controls) the overall estimated relative risk of acoustic neuroma was 0.90. Use of a cell phone for > 10 years did not increase acoustic neuroma risk over that of short-term users. Furthermore, tumors did not occur more frequently on the side of the head on which the telephone was typically used, and the size of the tumor did not correlate with the pattern of cell phone use. The results of this prospective, population-based, nationwide study, which included a large number of long-term users of cellular telephones, do not support an association between cell phone use and risk of acoustic neuroma^ref. Even in Sweden (148 patients and 600 controls) the overall OR for VS associated with regular mobile phone use is 1.0, but 10 years after the start of mobile phone use the estimates relative risk increases to 1.9; when restricting to tumors on the same side of the head as the phone is normally used, the relative risk is 3.9^ref.
• use of a mobile phone, either in the short or medium term, was not associated with an increased risk of glioma among 966 people aged 18 to 69 years diagnosed with a glioma from 1 December 2000 to 29 February 2004. This is consistent with most but not all published studies. The complementary positive and negative risks associated with ipsilateral and contralateral use of the phone in relation to the side of the tumour might be due to recall bias. The overall odds ratio for regular phone use was 0.94 (CI₉₅ = 0.78 to 1.13). There was no relation for risk of glioma and time since first use, lifetime years of use, and cumulative number of calls and hours of use. A significant excess risk for reported phone use ipsilateral to the tumour (1.24, 1.02 to 1.52) was paralleled by a significant reduction in risk (0.75, 0.61 to 0.93) for contralateral use^ref
• cutaneous blood flow is modified by non-ionizing electromagnetic radiations, emitted by a cellular phone^ref :
• without CP contact with the skin
• CP turned off but in contact with the ear skin : + 61.38%
• CP contact and turned on : + 131.74%
• CP contact, turned on and receiving : + 157.67%
• CP contact and set turned on : + 139.21%
• CP contact and turned off : + 122.90%;
• without CP contact : 57.58+/-10 PU
In such exposures, the electromagnetic energy may reach very high values of power density in peak at relatively low time-averaged levels of power density.
Web resources :
• Independent Expert Group on Mobile Phones (IEGMP)
• Stewart Report : "Mobile Phones and Health" : children could be more at risk from the radiowaves emitted by mobile phones because their brains are still developing and their skulls are thinner, making it easier for the radiowaves to penetrate them.
• Mobile Operators Association (MOA), formerly known as the Mobile Telecoms Advisory Group (MTAG) within the Federation of the Electronics Industry (FEI)
• National Radiological Protection Board (NRPB)
• Advisory Group on Non-Ionising Radiation (AGNIR)
• Advisory Group Report
• INTERPHONE Study, coordinated by the WHO's International Agency for Research on Cancer (IARC) in Lyon, France, was set up in 1998 to investigate whether exposure to the radio-frequency electromagnetic fields from mobile phones causes damaging health effects. It involves 13 countries (Australia, Canada, Denmark, Finland, France, Germany, Israel, Italy, Japan, New Zealand, Norway, Sweden and the UK). In order to maximise the power of finding a risk if it exists, the studies are mainly focused on tumours in relatively young people (30-59 – who had the highest prevalence of mobile phone use 5 to 10 years ago) and on regions within the participating countries with longest and highest use of mobile phones. It is expected that the studies will include about 6000 cases of gliomas and meningiomas (both benign and malignant), 1000 cases of acoustic neurinoma, 600 cases of parotid gland tumours and their respective controls. Studies are now complete in nearly all the countries involved in the INTERPHONE project, and the final results are expected to be released in early 2005, according to Elisabeth Cardis, chief of the radiation and cancer unit at the IARC. 5 of the countries involved in the project are also planning to start prospective studies following 250,000 people (50,000 in each country) to confirm any effects that INTERPHONE finds.
• super high frequency (SHF) (3 < n < 30 GHz; 1 < l < 10 cm)

Sources :
• communication with satellites
• civilian, police and military RAdio Detecting And Ranging (RADAR) used on aircraft, ships and weather forcasters : 1,300 to 1,600 MHz. An electronic instrument using UHF radio waves to detect distant objects and measure their range by how they scatter or reflect radio energy. Precipitation and clouds are detected by measuring the strength of the electromagnetic signal reflected back. Examples are doppler radar (weather radar that measures direction and speed of a moving object, such as drops of precipitation, by determining whether atmospheric motion is horizontally toward or away from the radar. Using the Doppler effect, it measures the velocity of particles) and next generation weather radar (NEXRAD) (a network of advanced Doppler radars implemented in the United States between 1992 and 1996, it detects the location and intensity of precipitation out to a range of 143 miles from the radar site. NEXRAD Doppler radar is highly sensitive and can detect precipitation from very light rain and snow up to the strongest thunderstorms with accuracy and detail. Sometimes, however, the radar's extreme sensitivity will cause ground clutter and other non-precipitation echoes to be displayed in the vicinity of the radar site)
• long distance trunk telephone communications
• TErrestrial Trunked RAdio (TETRA)
• microwave ovens : 2.45 GHz (MW are made by a magnetron)
• extra high frequency (EHF) (30 < n < 300 GHz; l < 1 cm)

Sources :
• cosmic microwave background radiation (CMR) is the leftover heat emitted 400,000 years after the big bang. It permeates the entire universe at a temperature of 2.725 +/- 0.001°K. Close examination of slight CMR intensity variations in different parts of the sky help cosmologists study the formation of galaxies. The intensity is measured in Mega Jansky per steradian
• not much used for radio communication, because of the technological difficulty of encoding and decoding amplitude and frequency modulation at such high frequencies.
Other sources : pulsed electromagnetic fields (PEMFs)
• a variety of industrial inductive and dielectric heating devices
• traffic speed cameras
• medical devices such as MRI and diathermy devices
• stars
Medical applications : microwave coagulation therapy (MCT)
Biological effects :
• non-thermal effect
• no evidence of a co-promoting effect of exposure to GSM-900 signals using the 7,12-dimethylbenz(a)anthracene (DMBA) female Sprague-Dawley rat model^ref
• thermal effect : they are absorbed by the lens causing acquired cataract
Web resources : Neurological effects of radiofrequency electromagnetic radiation
• infra-red (IR) radiations (0.3 < n < 385 THz; 760 nm < l < 1 mm)
• near-IR (NIR) : 0.76 - 5 mm

Applications : metal nanoshells
• mid-IR (MIR) / intermediate IR (IIR) : 5-30 mm
• far-IR (FIR) : 30-1000 mm
Sources :
• fire
• living organisms
• remote control signals can be detected by most camcorders
• night vision scopes/goggies use a special camera that senses IR ands converts the image to visible light. Some IR cameras employ an IR lamp to help illuminate the view.
• IR LASERs are used for burining objects (ex. product best-before date-codes)
Detection : heat receptors (some snakes have IR sensors)
Biological effects : they are absorbed by the lens causing acquired cataract
• visible light (385 < n < 750 THz; 400 < l < 760 nm)

Sources : Sun optic window 290-1400 nm
Laboratory examinations : luximeter (luminance)
Biological effects :
• vision
• photosynthesis
• retinal burns
• computer vision syndrome (CVS)
• asthenopia, headache
• retinal degeneration from chronic exposure to blue light
The diodes used in solar cells work at a potential difference of about 0.6 V, so every visible photon has enough energy to shift one electron across the interface
• ultra-violet (UV) radiations (750 < n < 3,000 THz; 200 < l < 400 nm) : beyond the violet end of the spectrum; said of electromagnetic rays or radiation between the violet rays and the x-rays. These rays have powerful actinic and chemical properties. Physicists have divided UV light into :
• near UV (NUV) : 300-400 nm (near the visible spectrum)
• medium UV (MUV) : 200-300 nm
• vacuum UV (VUV) / far UV (FUV) : 100-200 nm
• extreme UV (EUV / XUV) : 10-100 nm
In the 1930's the Commission Internationale de l'Eclaraige (CIE : International Commission on Illumination) introduced for photobiological spectral bands :
• ultraviolet A (UVA) (320 < l < 400 nm), comprising > 99% of UV reaching the surface of the earth. UVA enhances the harmful effects of UVB radiation and is also responsible for some photosensitivity reactions; it is used therapeutically in the treatment of a variety of skin disorders.
• UVA-1 (340 < l < 400 nm)

Biological effects : they are absorbed by the derm and vitreous humor
• UVA1/2 for DNA altering effects at 340 nm.
• UVA-2 (320 < l < 340 nm)

Biological effects : they are absorbed by the derm and vitreous humor, and can inactivate previtamin D₃
• ultraviolet B (UVB) (290 < l < 320 nm : the CIE originally divided UVA/B at 315 nm, later some photo-dermatologists divided it at 320 nm), comprising < 1% of the UV radiation reaching the earth's surface

Sources : those produced by the Sun are partially filtered by ozonosphere
Biological effects : they are absorbed by
• basal layers of the epidermis
• convert provitamin D₃ in previtamin D₃
• acute exposures leads tosunburn
• chronic exposure leads to
• atrophic/dystrophic dermatitis
• damaging photochemical changes within cells, including damage to DNA, leading to premature aging of the skin, premalignant and malignant changes, and a variety of photosensitivity reactions
They induce a transient appearance of neutrophils in papillary derm already 5 hrs after irradiation, reaching a peak at 24 hrs : this causes a T_h2 shift thanks to IL-4.
• minimal erythemogenic dose (MED) is the quantity of radiant energy required to produce a E+/- erythema 24 hours after exposure. A template with holes (approximately 1 x1 cm) is placed on a sun-protected area (hip or buttock) which is then irradiated with different doses of UV-B at a fixed distance. If broadband UVB are used, the following escalating doses are recommended : 20, 40, 60, 80, 100, and 120 mJ/cm²; if narrowband UVB are used : 200, 400, 600, 800, 1000, and 1200 mJ/cm²
The erythema action spectrum is believed to parallel the one for carcinogenesis. UV-induced DNA damage gives rise to mutations and skin cancer.
Prevention :
• sunscreens and other skincare products already contain a range of products - such as antioxidants from green tea - which are thought to prevent DNA damage. But because these are marketed as cosmetics, they have not been as rigorously tested as drugs. They passively block damaging UV rays but are sometimes ineffective because users often do not apply them frequently enough or in sufficient quantities
• dioxybenzone : an ultraviolet sunscreen applied topically to the skin
• bacterial DNA repair enzyme T4 endonuclease V in a liposomal delivery vehicle applied topically (T4N5 liposome lotion) lowers the rate of new actinic keratoses and basal-cell carcinoma in patients with xeroderma pigmentosum^ref
• treatment of skin cells in vitro with thymidine dinucleotide (pTT) activates p53^ref and increases the ability of cells to repair subsequent UV-induced DNA damage by enhancing endogenous DNA repair capacity^ref. Topical pTT pretreatment enhances the rate of DNA photoproduct removal, decreases UV-induced mutations, and reduces photocarcinogenesis in UV-irradiated hairless WT repair-proficient and Xpc^+/- heterozygous partially repair-deficient mice, both transgenic for the lacZ/pUR288 mutation-indicator gene : treated animals stayed free of pre-cancerous skin lesions for 16 weeks, while unprotected ones succumbed after 9 weeks. These data support the existence of inducible mammalian DNA damage responses that increase DNA repair capacity after DNA damage and hence reduce the impact of future exposures to environmental carcinogens. The ability of topically applied pTT to induce protective physiologic responses that normally result from DNA damage suggests a previously undescribed means of reducing skin cancer in high-risk individuals : the fragments could be a powerful new ingredient in sunscreens - one whose effect lasts days rather than hours^ref
• cornea
• vitreous humor
Applications : treatment of skin disorders.
• ultraviolet C (UVC) (200 < l < 290 nm)

Sources :
• Sun => they are totally filtered by ozonosphere
• artificial source
Biological effects : absorbed by cornea and epidermis
Applications :
• used for germicidal purposes
• ultraviolet phototherapy
Sources :
• Sun
• objects hotter than the sun (eg some massive young stars)
Biological effects : a UV photon has enough energy to damage DNA molecules in your cells
Bumble-bees can see light in the UVA range and so flowers have UV colours to attract them (bees can also see the polarisation of light, which they use to navigate)
Laboratory examinations :
• field analyzers (e.g. TE307 Acritalia or 15 ID Alenia) (from ELF to UHF)
• magnetic field (H) [A/m or tesla (T)]
• electric field (E) [V/m]
• power density (S) = E x H [W/m²] (from SHF to EHF)
• spectrum analyzer (e.g. Hewlett Packard)
• specific absorption rate (SAR) [W/kg] (from VHF to EHF)
• biological effects of ionizing radiation (BEIR)
Electromagnetic interference (EMI) : despite the introduction of modern pacemakers (PM) and bipolar lead systems, EMI still remains to be a concern during daily lives when patients are exposed to cellular phones, electronic security systems, and several household appliances : anyway there is no EMI risk of an induction oven in patients with bipolar or right-sided unipolar pacemakers^ref
Web resources :
• The International EMF Project at WHO
• International Commission on Non-Ionizing Radiation Protection (ICNIRP)
• actinic or ionizing radiations (IR) : pertaining to those rays of light beyond the violet end of the spectrum (E > 12.4 eV; n > 3,000 THz) that produce chemical effects, as in photography or heliotherapy (actinism / actinicity)
• X rays or Röntgen rays (10 pm < l < 200 nm; 3 ^. 10⁸ < n < 3^.10⁹; 12.4-124 keV)
• 'soft' X rays with longer wavelengths and lower energies are stopped by (enough) air
• 'hard' X rays with shorter wavelengths and higher energies can penetrate deeply into tissue
Sources :
• natural
• some radioactive sources
• very hot objects like neutron stars
• artificial
• kV : conventional roentgentherapy. X-ray machine : smashing DV-accelerated (high energy) electrons into heavy metal targets. X-ray emission apparatuses include
• vacuum tube : a glass tube from which the air has been exhausted to a high degree of vacuum.
• x-ray tube : a glass vacuum bulb containing a diode with DV = 40-150 kV : the cathode (₇₄W) expell electrons by thermoelectric effect (DV = 10 V) towards a rotating anodic disc : catodic electrons interacts with both anodic electrons (one inner anodic electron is excited and replaced by an outer electron, generating heat for 99% and characteristic X-rays for 1%) and anodic nuclei (₇₄W) generating a continuum spectrum of braking radiations). The mA current modifies the width of the focal spot. By increasing
• catodic DV => increased electron expulsion => increased X-ray flow
• catodic-anticatodic DV => increased electron energy => increased X-ray energy => hard X-rays

• Chaoul tube : a low voltage x-ray tube so designed as to permit the anode to be located at 2 cm. from the body, thus permitting intense but very superficial tissue penetration of the ionizing radiation beam.
• Coolidge tube : a vacuum tube for the generation of x-rays in which the cathode consists of a spiral filament of incandescent tungsten and the anode (the target) of massive tungsten.
• Olshevsky tube : an x-ray tube constructed to use only the stronger rays which pass through the target and armoring the rest of the tube.
• exit window
• filter which eliminates low-energy (ie high-wavelenght) characteristic X-rays
• collimator
X photons interact with patient's atoms in 3 ways :
• classical or coherent diffusion => photon diffusion
• photoelectric effect
• Compton effect (conventional X-rays)
• MV :
• linear accelerator (LINAC)  : machine generating ionizing radiation from electricity; these machines are commissioned to treat with x-rays (E = 4-20 MeV) or electrons; depth of treatment varies with energy and type of radiation
• betatron : an apparatus for accelerating electrons to millions of electron volts by means of magnetic induction
Biological effects : their energies are enough to ionise atoms and to destroy chemical bonds
Applications : radiotherapy
• extremely high (millimetre waves, MMW) frequency electromagnetic fields
• g rays (l < 10 pm)

Sources :
• byproduct of radioisotope decays (e.g. ⁶⁰Co or ¹³⁷Cs)
Applications : radiotherapy
Symptoms & signs : after the nuclear power accident at Chernobyl on April 26, 1986, some of the radioactive emissions were carried by the wind to Sweden. Heavy rain caused a relatively large amount, about 5 percent of the Cesium-137 released in the disaster, fell on Sweden, above all along the coastal area of Northern Sweden and northern central Sweden. The fallout in Sweden was unevenly distributed and, compared with the areas close to the nuclear power station at Chenobyl, considerably less. Anyway a statistically determined correlation between radioactive fallout from the Chernobyl accident and an increase in the number of cases of cancer in the exposed areas in Sweden is reported during the years 1988 through 1996. There is a statistically established correlation between the degree of fallout and an observed rise in the number of cancer cases. The increase involves all types of cancer in the aggregate. On the other hand, no clear effect can be seen for individual forms of cancer, not even for those types that have been regarded as especially susceptible to radiation, such as leukemia or thyroid cancer. It is remarkable that an increase in cancer morbidity could have occurred after such a relatively short time following the accident, but just such a short time period has been described for groups exposed to radioactive radiation. If the correlation found here is not a product of chance, or other unknown disturbances than those corrected for in the analysis, then one possible explanation is that the radiation hastened the growth of already established tumors in their early stages, rather than that new tumors occurred.
Dosimetry^ref : the determination by scientific methods of the amount, rate, and distribution of radiation emitted from a source of ionizing radiation
• physical dosimetry : the determination of the level of exposure to ionizing radiation by means of radiation measuring instruments such as environmental monitoring devices or individual dosimeters.
• counter : a device for enumerating ionizing events
• Geiger-Müller counter : a radiation counter that uses a gas-filled tube to indicate the presence of ionizing particles; the type and energy of a particle cannot be determined because the degree of ionization produced is independent of them. It is highly sensitive to b particles, but relatively insensitive to g and x-rays.
• proportional counter : a gas-filled radiation detection tube in which the pulse produced is proportional to the number of ions formed in the gas by the primary ionizing particle; thus it is possible to discriminate among radiations of different energies or types.
• scintillation counter : an instrument for indicating the emission of ionizing particles, making possible the determination of the concentration of radioactive isotopes in the body or other substance; the radiation is absorbed by a specific type of crystal or liquid that subsequently emits minute flashes of light, which are detected and amplified by a photomultiplier tube and counted if they fall within a preset window of energies characteristic of the radioisotope in question
• scintillation or gamma camera : an electronic instrument that produces photographs or cathode-ray tube images of the gamma ray emissions from organs containing tracer compounds
• Anger camera (the original and most commonly used type) : a device used to form an image of the distribution of a gamma ray–emitting radionuclide in a patient. The radiation is passed through a collimator to reduce scatter and interacts with a sodium iodide crystal, resulting in the production of pulses of light, which are detected and converted to amplified electrical signals by an array of photomultiplier tubes behind the crystal. A pulse height analyzer then discards all but those signals arising from the photopeak of the nuclide being imaged, and the remaining signals are used to form an image of the distribution of the radionuclide on a cathode ray tube. It was the original, and is by far the most commonly used, form of scintillation (or gamma) camera, and the terms are often used interchangeably.
• multicrystal versions
• dosage meter / dosimeter : in radiology, an instrument used to detect and measure exposure to radiation of either personnel or radiotherapy patients
• film badge : a pack of radiographic film or films, usually worn on the body during potential exposure to radiation in order to detect and quantitate the dosage of exposure. A.k.a. thermoluminescence dosimeter : thermoluminescence is the production of light by a substance when its temperature is increased
• source activity : 1 Bq (becquerel) = 1 dis/s = 2.7 x 1011 Ci (curie) / mol . 1 Ci = number of disintegrations/s in 1 g of ²²⁶Ra ===> ²²²Rn + a
• linear energy transfer (LET) : total charge of ions (keV) / mm
• high LET (low penetration and direct, densely ionizing) : particulated radiations, less influenced and poorly sensitive to O₂ sensitization
• low LET (high penetration and indirect, sparsely ionizing) : b^- and EMR, highly sensitive to O₂ sensitization
• doses usually referred to a given time
• exposure dose (total electric charge of produced ions / 1 Kg of air) : 1 C/Kg = 3876 R (röntgen) . 1 R = dose of 250 keV X-rays that in normal conditions (T = 0°C and P = 1 atm) is able to produce 2 x 10⁹ ion pairs in 1 cm³ of air in 1 minute.
• Behnken's unit (R) : a unit of x-ray exposure, being that quantity which, when applied in 1 cc of air at 18°C and 760 mm Hg of pressure, engenders sufficient electric conductivity to equal one electrostatic unit, as measured by the saturation current
• Hampson unit : a unit of x-ray exposure; it is one quarter of the erythema dose.
• Kienböck x-ray unit (X) : a unit of x-ray exposure equal to 0.1 erythema dose
• absorbed dose (absorbed energy / tissue mass) = 1 Gy (gray) = 1 J / kg = 100 rad (radiation absorbed dose). 1 rad = 100 erg/g (about 1 R / g)
• specific absorption rates (SARs) averaged over the whole body (W/Kg)
• equivalent dose (absorbed dose from radiations of every type) : 1 Sv (sievert) = 100 REM (röntgen equivalent in man). 1 REM = 1 rad of radiations of every kind.
• relative biological effectiveness (RBE) : the rate between the absorbed dose of standard radiation (X rays with E = 250 keV) able to produce a given biological effect and the absorbed dose of every radiation that produces the same biological effect. It depends on LET
• ionization chamber : a device for measuring ionizing radiation by the measurement of the ionization of the gas contained in the chamber
• free-air ionization chamber : an ionization chamber in which the ionization in an accurately defined volume of free air is measured
• air-equivalent ionization chamber : in radiology, a chamber in which the materials of the wall and electrodes are such that ionizing radiations produce ionization essentially similar to that in a free-air ionization chamber
• thimble chamber : a small, thin-walled ionization chamber, usually with walls of organic material; used as a dosimeter
• tissue-equivalent ionization chamber : an ionization chamber in which the walls, electrodes, and gas are selected to produce ionization essentially equivalent to that which would occur in the tissue under consideration
• biological dosimetry : the determination of the level of exposure to ionizing radiation by measurement of radiation-induced changes such as cytogenetic abnormalities, lymphopenia, and agranulocytosis; the dose is estimated by comparison of the measurements under consideration to those observed in prior radiation accidents.
Radiobiology is the study of events that occur after ionizing radiation is absorbed by a living organism :
• physical stage : excitation and ionization of atoms or molecules
• thermic effect (if E < 1 eV : i.e. from microwaves up to far IR)
• exciting effect (if 1 eV < E < 10 eV : i.e. from near IR up to UV-C). The excited molecule is less electrophilic and so it may be more easily oxidized, producing redox reactions or free radicals (e.g. through photodynamic effect mediated by photosensitizers cycling (380-410 nm : porphirins; 453 nm: bilirubin; eosin; 340-360 nm: flavin; melanin). UVC are specifically absorbed by the aromatic groups in nucleobases (l₁ = 260 nm) leading to dimer formation between consecutive thymine residues in DNA and by aromatic groups in aromatic amino acids (l₁ = 280 nm)
• ionizing (or radicalizing) effect (if E > 10 eV : i.e. X and g electromagnetic radiations and all particulated radiations)

The ionizing mechanism may be :
• Hallwachs photoelectric effect (if 10 eV < E < 0.1 MeV) : incident photon energy is greater than the binding energy of the electron (depends on E^-3 and Z³) => expulsion of a same-energy photoelectron from inner orbitals; no radiation results
• Compton effect or scattering (if 0.1 < E < 10 MeV) : incident photon causes ejection of a Compton recoil electron from outer orbitals (depends on E^-1); a reduced energy photon is scattered by a given angle. In Homo sapiens it occurs only in bones.
• coherent difusion effect : incident photon s deviated by an atomic electron without loss of energy
• pair-production effect (if E > 1.02 MeV) : the incident photon interacts with the nucleus (given that the rest mass of an electron is 0.511 MeV and E=mc², a photon must have at least 1.022 MeV of energy to produce an electron-positron pair) => a b⁺ and a b^- pair results => they annihilate themselves into 2 180°-opposed annihilation photons (g rays each with E = 0.511 keV)
The atomic ionization may be ...
• direct ionization (rare) by charged particles a, b^-, b⁺ and H⁺ : they produce ion pair
• indirect ionization (common) by uncharged particles (neutrons) and X and g electromagnetic radiations : they produce charged particles
• chemical stage : formation of highly reactive free radicals. The biopolymers ionization may be...
• direct ionization (rare)
• indirect ionization (common) : mediated by H₂O ionization or homolysis, both leading to ^.OH production
Ionized molecules may undergo homolysis after reduction or heterolysis. O₂ has a radiosensitizing effect because peroxyls can only be reduced to hydroperoxyls but never reversed !
• biological stage :
• damage to critical targets :
• nuclear DNA : large-sized, complex molecule with difficult repair. Most repair is believed to occur within 6 hours after a treatment.
• single chromosomal strand breaks (SSB) :
• generally repaired readily
• misrepair may result in chromosomal aberrations
• lethal somatic mutation => delayed mitotic or reproductive cell death
• chromosome damage may cause reproductive failure (death at the time of cell division).
• apoptosis is enhanced by toxic treatments
• germinal mutation : heritable change in genes expressed in later generations
• carcinogenesis (somatic cells) : chromosome aberration that may cause oncogene activation or suppressor
• gene loss
• double chromosomal strand break (DSB) are more difficult to repair and may activate an oncogene or inactivate a tumor suppressor gene.
• mitotic or reproductive cell death
• mutation
• carcinogenesis
• only in indirect ionization : damages to nitrogenated nucleobases
• only in indirect ionization :
• proteins
• phospholipid peroxidation
• induction of STP activating expression of genes mediating tissue response
Effects :
• genetic effects (stochastic) : DNA mutations
• somatic effects
• stochastic : cancers
• nonstochastic (see below)
Radiosensitivity is the innate sensitivity of cells, tissues, or tumors to radiation. Both normal and cancer cells are affected by radiation
• factors that influence radiation sensitivity include the following
• increasing radiosensitivity :
• cells in late G₂ and M phases
• hyperoxia. Reoxygenation occurs as the tumor shrinks during RT and previously hypoxic cells become better oxygenated
• poor differentiation (however associated with higher histological grading)
• rapidly dividing cells (anyway also poorly dividing cell types as small lymphocytes and salivary gland cells may experience an interphase death)
• increasing radioresistance :
• cells in the late S phase
• hypoxia
• high differentiation
• nondividing or slowly dividing cells
• large tumor size (often indicates a poorly oxygenated mass that, thus, is less radiosensitive)
• factors related to radiation-induced injury of normal tissue
• patient-related factors
• age
• in children : growth-related factors (e.g., growth retardation, endocrine changes)
• in adults : limited data available
• hemoglobin level
• low hemoglobin has been found to decrease local control probability in cancers such as squamous cell carcinoma of the head and neck, carcinoma of the cervix, and transitional cell carcinoma of the bladder
• little information is available concerning hemoglobin level related to normal tissue reactions.
• smoking : can enhance some early and late effects
• tumor invasion : may interfere with normal tissue reactions
• infection : may increase normal tissue injury, especially when the immune system is compromised
• intrinsic radiosensitivity
• genetic syndromes : clastogenias are associated with increased sensitivity to RT
• autoimmune diseases (e.g., systemic lupus erythematosus)
Tolerance doses (TD) of various normal organs

organ	severe complications	minimal tolerance dose 5/5 (cGy) = the dose, given to a population of patients under a standard set of treatment conditions, that will result in no more than a 5% rate of severe complications within 5 years after treatment.	maximal tolerance dose 50/5 (cGy) = the dose, given to a population of patients under a standard set of treatment conditions, that will result in a 50% rate of severe complications within 5 years after treatment.	whole or partial organ (field size or length)
bone marrow	pancytopenia, leukemias	250 3,000	450 4,000	whole  segmental
liver	acute and chronic hepatitis	2,500 1,500	4,000 2,000	whole  whole (strip)
stomach	perforation, ulcer, hemorrhage	4,500	5,500	100 cm
intestine	radiation enteritis, radiation colitis, radiation proctitis, ulcer, perforation, hemorrhage	4,500 5,000	5,500 6,500	400 cm  100 cm
encephalon	infarction, necrosis	5,000	6,000	whole
spinal cord	infarction, necrosis (radiation myelopathy and transverse myelitis)	4,500	5,500	10 cm
heart	pancarditis (radiation myocarditis and radiation pericarditis)	4,500 7,000	5,500 8,000	60%  25%
lungs	acute and chronic radiation pneumonitis, lung cancer	3,000 1,500	3,500 2,500	100 cm  whole
kidneys	acute and chronic nephrosclerosis	1,500 2,000	2,000 2,500	whole (strip)  whole
bladder	radiation cystitis
fetus	death	200	400	whole
skin	burn wounds, X-ray dermatitis / radiodermatitis, photodermatitis, photoaging, freckle / ephelis, cutaneous malignant melanoma, cutaneous squamous cell cancer (SCC)
thyroid	papillary thyroid carcinoma (90%)
bone	osteosarcoma

Manifestations of radiation effects occur at different times for different tissues
• acutely responding tissues : damage to epithelial stem cells in rapidly rennovating tissues and flogosis due to necrosis mediators => reversible mucositis and erythema within hours to days
• bone marrow
• ovaries : 2 Gy can wipe out 50% of a woman's oocytes : even women receiving a fraction of a standard dose of abdominal, pelvic or total-body irradiation could be left infertile or have an earlier menopause. In cases where chemotherapy is a good alternative, medics could avoid radiation except as a last resort. For many years these side effects have been largely ignored as doctors focused on the more pressing issue of survival : improved treatments now mean that many women survive once-fatal cancers, so patients' subsequent quality of life is being taken into account. Some women facing cancer treatment are given the opportunity to have their oocytes or ovarian tissue frozen, in the hope of using them in assisted-reproduction techniques later.
• testes
• lymph nodes
• oral mucosa
• salivary glands
• esophagus
• stomach
• small bowel
• colon
• larynx
• arterioles
• capillaries
• skin
• bladder
• vagina
• postirradiation syndrome : a symptom complex caused by massive irradiation, with hemorrhage, anemia, and malnutrition
• acute radiation syndrome : a syndrome caused by exposure to a whole-body dose of over 1 Gy of ionizing radiation. Symptoms, whose severity and time of onset depend on the size of the dose, include erythema, radiation enteritis (nausea and vomiting, diarrhea, gastrointestinal hemorrhage), fatigue, fever, petechiae, bleeding from the mucous membranes, lymphocytopenia, granulocytopenia, and thrombocytopenia, epilation, systemic arterial hypotension, tachycardia, and dehydration; death may occur within hours or weeks of exposure.
• subacutely responding tissues demonstrate effects in weeks to several months after RT and include :
• lungs
• liver
• kidneys
• heart
• CNS :
• encephalon
• somnolence syndrome : a transient condition of drowsiness, lethargy, anorexia, and irritability with electroencephalographic changes, occurring in children after irradiation of the head in the treatment of brain tumors, acute leukemia, or non-Hodgkin's lymphoma.
• spinal cord : transverse myelitis due to endovasculitis
• late-responding tissues : chronic damage to parenchymal tissues due to impaired vascularization and sclerosis => effects months to years after RT and include :
• lymph vessels
• thyroid
• pituitary gland
• breasts
• connective tissues
• bones
• cartilage
• endocrine pancreas
• uterus
• bile ducts
• muscles
IR can cause cancer by :
• DNA mutagenesis
• epigenetic mechanisms => down-regulation of E-cadherin and b-catenin (vital for cell-cell adhesion) and connexin 43 (a component of gap junctions) heritable disruption of epithelial cell interactions^ref
Primary prevention : radioprotectant therapy
• human serum albumin (HSA)
• glycerol
• aminothiols
• N-acetyl cysteine (NAC) isomers
• L-N-acetyl cysteine (LNAC)
• D-N-acetyl cysteine (DNAC)
• cysteamine
• amifostine
• strawberries and blueberries are used in diet of astronauts to protect brain cells from cosmic rays during travels beyond Earth's protective magnetic field
• Ca-channel blockers
• acylmelatonin homologs
• substituted anilines
• curcumin
• liposomal lipid A
• 21-aminosteroid U-74389G
• glutamine (a conditionally essential amino acid)
• vitamin C
• vitamin E (more efficacious when given subcutaneously than when given orally)
• pentobarbital acts as a cerebral radioprotectant
• pilocarpine, a salivary stimulant, has been shown to protect salivary glands from g-radiation-induced damage during the radiotherapy of head and neck tumors
• atropine acts as an intestinal radioprotectant
Web resources :
• US Nuclear Regulatory Commission (NRC)
• National Radiological Protection Board (NRPB)
Doctors across Europe are complaining loudly about new regulations on radiation exposure, which they say will needlessly hinder their use of MRI when treating patients. The European Union Physical Agents Directive, set to become law in April 2008, is aimed at protecting workers in telecommunications and the electricity industry from possible health risks caused by exposure to electromagnetic radiation. Strong fields can induce a current within tissues, which heats them up and may cause damage. Some controversial studies have suggested that such fields may also damage DNA. But the rules will also keep doctors away from MRI machines, which are another source of electromagnetic radiation. This will prevent nervous patients from being accompanied during scans, and may even restrict proper cleaning of the devices. MRI scanners are not dangerous, and that although the electromagnetic frequencies from these devices can gently heat tissues and stimulate nerves in the spine, this does not lead to damage because the heating effects are miniscule. MRI scans have been used to see inside the human body since the beginning of the 1980s, with no known ill effects. Any firm evidence of adverse effects from standing next to a scanner is sparse : unpublished conference abstracts may have fuelled the directive and the advisory guidelines that precede it. Doctors are right to point out the lack of clear evidence of harmful effects, but we are dealing with a new technology and perhaps a bit of caution is necessary. We can't rule out any long-term effect. The directive will turn the UK's current advisory guidelines into law. These guidelines are based on the advice of the International Commission on Non-ionizing Radiation Protection and the National Radiological Protection Board (NRPB). Researchers say these guidelines are also strict, but few people have complained as they are only voluntary. The patients most affected by the changes will probably be anxious children and patients requiring specialized heart investigations. In the absence of a comforting hand, scared children may undergo more harmful but less intimidating X-ray imaging. And nervous patients may have to be anaesthetized before being scanned, subjecting them to an unnecessary risk. Certain heart procedures may also face difficulties. In cardiac catherization, for example, a doctor uses an MRI scan to help guide a tube up the patient's leg to their heart. This would not be possible if the doctor was not allowed in the scanning room. Cleaning the magnet will also be a problem, as technicians will no longer be allowed to get near the magnet. Technicians have been advised to clean the magnet with a sponge on a stick. Given the risk of superbugs, Keevil is horrified at this prospect. Several leading experts in the UK have written to the Secretary of State for Health, requesting 2 years to do research that will justify relaxing the limits in the directive.
• particulated radiations
• neutrons
• slow or thermic neutron : E < 1 MeV
• fast neutron
Sources :
• uranium fission
• cyclotron : large, electrically powered machine that produces neutrons by smashing accelerated deuterons into ³H or Be targets => H⁺, ions with E = 60-300 MeV
• ¹H⁺ (proton) :

Sources : cyclotron
Properties : high LET, straight trajectory, gradual decay =>
• ²H⁺ (deuteron : i.e. proton + neutron) :
• a radiation (⁴He²⁺). E < 3 MeV. Only isotopes with Z > 82 and A > 200 may give such a decay.

Sources :
• cyclotron
• radioisotopes
• b⁺radiation (antielectrons) : only isotopes in which n/p < 1 give such a decay.

Sources :
• radioisotopes
• b^-radiation (electrons) : only isotopes in which n/p > 1 give such a decay.

Sources :
• linear accelerator (LINAC)
• betatron
• radioisotopes
Properties : unelastic collisions => deviated trajectory, high LET, uniform dose in successive layers and sudden decay => ideal for radiotherapy
• meson (p^-) radiation : a short-lived subatomic particle of a mass usually less than that of a proton but more than that of an electron; it may carry either a positive, a negative, or a neutral electric charge.

Sources : smashing accelerated protons into beryllium targets
Properties : ionization density is maximal in depth => ideal for in-depth radiotherapy
• cosmic rays : low fluxes of energetic heavy ions which may be galactic, solar or terrestrial, left over from the Big Bang : during a spacewalk, an astronaut is hit by about 27 times as many cosmic particles than a person on Earth. Matroshka, an 80-kilogram limbless, life-sized mannequin made of natural bone and plastics of various densities that serve as fake organs, will test the human body's exposure received by individual organs in the International Space Station. The doll is coated with a carbon-fibre covering that blocks ultraviolet radiation and deflects space debris, much as a space suit protects a live astronaut. And it has strategically placed radiation sensors to measure cosmic-ray doses to the stomach, lungs, kidneys, colon and eyes. It's because of all these layers that the mannequin is named after the famous hollow Russian dolls that open up to reveal ever-smaller versions of themselves inside. It is expected to spend a year strapped to the outside of the station's Russian Zvezda module, starting on 26 February. During that time, Matroshka will receive three times more radiation than a professional radiation worker's annual dose. Most spacecraft are made of aluminium, through which cosmic rays can easily pass. A round-trip to Mars would take more than two years - far longer than the record 679 days spent on Russia's Mir space station by cosmonaut Valery Polyakov in 1994-95
Sources
• radioactive heavy metals in the fallout nuclear bombs and in waste from nuclear power plants. The chemicals may also be used in a "dirty bomb", a conventional explosive device that contains a small amount of radioactive materials.
• ⁵⁶Mn (biologic t_1/2 = 5.7 days)

Sources : reactors, research laboratories
Exposure type : external, internal
Mode of contamination : not available
Focal accumulation in body : liver
Treatment : not available
• ⁶⁰Co (biologic t_1/2 = 9.5 days)

Sources : medical radiotherapy devices, commercial food irradiators
Exposure type : external, internal
Mode of contamination : lungs
Focal accumulation in body : liver
Treatment : gastric lavage, purgatives, penicillamine in severe cases
• ⁹⁰Sr (biologic t_1/2 = 18,000 days)

Sources : fission product of uranium
Exposure type : internal
Mode of contamination : moderate GI tract
Focal accumulation in body : bones, similar to calcium
Treatment : aluminum phosphate gel (PO 100 ml once immediately after exposure to decrease gut absorption) strontium, calcium, ammonium chloride
• ⁹⁹Mo (biologic t_1/2 = 3 days)

Sources : hospitals - scans
Exposure type : external, internal
Mode of contamination : not available
Focal accumulation in body : kidneys
Treatment : not available
• ^99mTc (biologic t_1/2 = 1 day)

Sources : hospitals - scans
Exposure type : external, internal
Mode of contamination : IV administration
Focal accumulation in body : kidneys, total body
Treatment : potassium perchlorate to reduce thyroid dose
• ¹³⁷Cs (biologic t_1/2 = 70 days)

Sources : medical radiotherapy devices
Exposure type : external, internal
Mode of contamination : lungs, GI tract, wounds, follows potassium
Focal accumulation in body : renal excretion
Treatment : ion-exchange resins, Prussian blue (PO 1 g tid with 100-200 ml water, up to 10 g/d) for >= 3 weeks titrated by urine and fecal bioassay and whole-body counting), chelation therapy
• ¹⁴⁴Ce
• ¹⁵³Gd (biologic t_1/2 = 1,000 days)

Sources : hospitals
Exposure type : external, internal
Mode of contamination : not available
Focal accumulation in body : not available
Treatment : not available
• ¹⁹²Ir (biologic t_1/2 = 50 days)

Sources : commercial radiography
Exposure type : external, internal
Mode of contamination : not available
Focal accumulation in body : spleen
Treatment : not available
• ²²⁶Ra (biologic t_1/2 = 16,400 days)

Sources : instrumental illumination, industrial applications, old medical equipment, former Soviet Union military equipment
Exposure type : external, internal
Mode of contamination : GI tract
Focal accumulation in body : bones
Treatment : MgSO₄ lavage, ammonium chloride, calcium alginates
• ³H (biologic t_1/2 = 12 days)

Sources : luminescent gun sights, muzzle-velocity detectors, nuclear weapons
Exposure type : internal
Mode of contamination : inhalation, GI tract, wounds
Focal accumulation in body : total body
Treatment : dilution with controlled water intake (PO > 3-4 L per day for 3 weeks), diuretics
• ¹³¹I (biologic t_1/2 = 138 days)

Sources : reactor accidents, thyroid ablators
Exposure type : internal
Mode of contamination : inhalation, GI tract, wounds
Focal accumulation in body : thyroid
Treatment : p.o. potassium/sodium iodide (130 mg/d for adults > 40 with thyroid exposure > 500 cGy; 130 mg/d for adults 18-40 with thyroid exposure > 10 cGy, 130 mg/d for pregnant or lactating women with thyroid exposure > 5 cGy; 65 mgd for children and adolescents 3-18 with thyroid exposure > 5 cGy, 16 mg/d for neonates from birth to 1 month with thyroid exposure > 5 cGy) for 7-14 days, propylthiouracil, methimazole
• ²³⁵U (biologic t_1/2 = 15 days)

Sources : depleted uranium, natural uranium, fuel rods, weapons-grade material. 230,000 tons of nuclear waste: that’s how much toxic metal can accumulate after 30 years of mining uranium - and that’s just one waste pile. With all the nuclear waste production throughout the world, this toxic metal is literally “piling up” in more and more places, and is encroaching on inhabited areas. During the process of generating nuclear power and nuclear weapons, radionuclides like uranium are discharged into the environment. These metals pose a serious ecological and health threat and usually contaminate the soil, sediment, and waters surrounding the waste piles. Conventional methods of cleaning up these toxic wastes are often expensive and not very effective. The environment is in dire need of a novel approach to waste clean-up and researchers in Germany may have the answer. Bioremediation is a process that uses microorganisms to return an environment back to its original condition after it has been exposed to contaminants. Nuclear waste pilesare a reservoir for certain strains of bacteria. These bacteria have evolved special mechanisms to survive in this waste that would normally be toxic to other types of microorganisms. The strain Bacillus sphaericus has evolved a crystalline surface layer (S-layer) that covers the outside of the cell. This layer is more than a protective barrier to the bacteria, it serves to accumulate high amounts of toxic metals such as uranium, lead, copper, aluminum, and cadmium. Researchers are currently seeking out ways to exploit the bacteria’s strategies. New technology is incorporating the S-layer structure onto silicon wafers, metals, polymers, nanoclusters, and bioceramic discs. All of these products could be used to remove metals from contaminated water and soil. Additionally, these technologies could be used to recover precious metals such as platinum and palladium from industrial waste sites and recycle them for making electronic products. Bacteria may be the template for new technology aimed at nuclear waste removal. The time may be near when synthetic S-layer discs can be placed in contaminated areas and act as sponges, cleaning up a big toxic mess (Pollman, Biotechnology Advances)
Exposure type : internal
Mode of contamination : GI tract
Focal accumulation in body : kidneys, bones
Treatment : NaHCO₃ (IV 2 ampules 44.3 mEq each, 7.5% in 1000 ml NS, 125 ml/l, or 1 ampule 44.3 mEq, 7.5% in 500 ml NS, 500 ml/h; PO 2 tablets every 4 h until urine pH = 7-8, or 4 g (8 tablets) 3 tid; usually IV for the first 3-4 hours, PO for additional 2 days; continuation of treatment for > 3 days is rare and can be done according to titration of uranium amounts in the body), chelation with EDTA
• ²³⁸U / depleted uranium (DU) (biologic t_1/2 = 15 days), a waste product of ²³⁸U enrichment, is a heavy metal that is 1.6-1.7 times denser than lead. The natural ²³⁵U/²³⁸U isotope ratio is 0.007222.

Sources :
• several civilian applications
• military applications (armor-penetrating munitions, military vehicle armor, and aircraft, ship and missile counterweighting/ballasting). Recent combat applications of DU alloy [i.e., 1991 Persian Gulf War (PGW) and Kosovo peacekeeping objective] resulted in human acute exposure to DU dust, vapor or aerosol, as well as chronic exposure from tissue embedding of DU shrapnel fragments. DU alloy is 99.8% ²³⁸U, and emits approximately 60% of the a, b, and g radiation found in natural uranium (4.05 x 10^-7 Ci/g DU alloy). During the Gulf conflict, Abrams tanks, Apache attack helicopters and A-10 tank-buster planes fired an estimated 300 tonnes of DU munitions : it was claimed to contribute to health problems such as acute myeloblastic leukemia (AML) and the so-named Gulf War syndrome / Balkan syndrome.
Pathogenesis : the radiological and chemical properties of DU can be compared to those of natural uranium, which is ubiquitously present in soil at a typical concentration of 3 mg/kg. Natural uranium has the same chemotoxicity, but its radiotoxicity is 60% higher.
• due to the low specific radioactivity and the dominance of a-radiation no acute risk is attributed to external exposure to DU
• the major risk is DU dust, generated when DU ammunition hits hard targets. Depending on aerosol speciation, inhalation may lead to a protracted exposure of the lung and other organs. After deposition on the ground, resuspension can take place if the DU containing particle size is sufficiently small. However, transfer to drinking water or locally produced food has little potential to lead to significant exposures to DU
It can remain within the body for many years and slowly solubilize. High levels of urinary uranium have been measured in PGW veterans 10 years after exposure to DU fragments and vapors.
Laboratory examinations : since poor solubility of uranium compounds and lack of information on speciation precludes the use of radioecological models for exposure assessment, biomonitoring has to be used for assessing exposed persons : urine, feces, hair and nails record recent exposures to DU.
Symptoms & signs :
• in rats
• there is strong evidence of DU accumulation in tissues including testes, bone, kidneys, and brain
• in vitro tests indicate that DU alloy may be both genotoxic and mutagenic
• in vivo study suggests that tissue-embedded DU alloy may be carcinogenic in rats. T
• about 116 in every 100,000 people were diagnosed in 2001 with cancer in the vicinity of Basra in southern Iraq, where the U.S. military used DU shells in the Persian Gulf War in 1991 : the number marks a 10-fold increase from the 11 cases diagnosed in 1988. An increasing number of families have members who are suffering from cancer, and the death toll from the disease has risen 19-fold during the same period. In 2001, 611 babies were born with no limbs, no eyes or other birth defects, compared with 37 such cases in 1990
• there is limited available data for reproductive and teratological deficits from exposure to uranium per se, typically from oral, respiratory, or dermal exposure routes. Alternatively, there is no data available on the reproductive effects of DU embedded
Prevention : adding acetate into contaminated underground aquifer stimulates the growth of Geobacter spp., which convert soluble uranium to insoluble uraninite, which stays put instead of mixing with water used for drinking or irrigation (70% in 50 days)
Treatment : NaHCO₃ (IV 2 ampules 44.3 mEq each, 7.5% in 1000 ml NS, 125 ml/l, or 1 ampule 44.3 mEq, 7.5% in 500 ml NS, 500 ml/h; usually IV for the first 3-4 hours, PO for additional 2 days; continuation of treatment for > 3 days is rare and can be done according to titration of uranium amounts in the body), chelation with EDTA
• ₉₄²³⁹Pu (biologic t_1/2 = 73,000 days)

Sources : produced from uranium in reactors, nuclear weapons
Exposure type : internal
Mode of contamination : limited lung absorption, high retention
Focal accumulation in body : lungs, bones, bone marrow, liver, gonads
Treatment : chelation therapy with Zn- or Ca-DTPA (IV 1 g in 250 ml NS or 5% glucose, given in 1-2 h, or bolus over 3-4 min; inhalation 1 g in 1:1 dilution with water or NS over 15-20 min; IM 1 g not recommended because of pain) for up to 5 days or EDTA
• ²⁴¹Am (biologic t_1/2 = 73,000 days)

Sources : smoke detectors, nuclear weapon detonation fallout
Exposure type : internal
Mode of contamination : inhalation, skin wounds
Focal accumulation in body : lungs, liver, bones, bone marrow
Treatment : chelating with Zn- or Ca-DTPA (IV 1 g in 250 ml NS or 5% glucose, given in 1-2 h, or bolus over 3-4 min; inhalation 1 g in 1:1 dilution with water or NS over 15-20 min; IM 1 g not recommended because of pain) for up to 5 days or EDTA
• ₉₅²⁴³Am

Chelation therapy
• ²¹⁰Po (biologic t_1/2 = 60 days)

Sources : calibration source
Exposure type : internal
Mode of contamination : inhalation, wounds
Focal accumulation in body : spleen, kidneys
Treatment : lavage, dimercaprol
• ²⁰⁴Tl (see also chemotoxicity)

Chelation therapy
• ²³²Th