Post on 24-Jan-2016
description
includes all kinds of electromagnetic radiations with frequencies < 1015 Hz and wavelengths λ = 10-8 - 104 m. i.e. ultraviolet radiation UV- light ,Visible light, Infrared radiation IR-light, Microwaves, Long ,Medium, Short, and Ultra-short radiowaves). These elmg. radiations never create electrically charged IONS (cations+ and anions-) when targeting atoms or molecules.γ-Rays X-rays UV VL IR MW R a d i o
I o n i z i nI o n i z i n gg N o n – I o n i z i n g
UV Light is invisible radiation with λ = 100- 400 nm,
Sources: natural (Sun), artificial (mercury lamps )
Classification:UVA- long wave,“black-tanning light“ λ = 315
- 400 nmUVB- medium wave,“inflamatory“λ = 280 - 315
nmUVC- short wave,“killing germs“λ = 100 - 280
nm (comes only from artificial sources)
Earth is targeted from Sun by UVA (90%) and UVB (10%) lights. 90% of UVB is absorbed by O3 and O2
Ozone O3 and O2 lower the intensity of UVA and UVB lights and totally absorb UVC light
Ozone holes- increase a level of UV radiation!
SkinSkin: ErythemaErythema- „early red coloured skin inflammation“(appears after 2-3 hours)
TanningTanning (delayed pigmentation, because
production of melanine.( it starts
approx. 24- 48 hours after expo-
sure) Vitamine DVitamine D production Skin AgingSkin Aging (Wrinkles, Dry skin, Skin
cancer-melanoma)EyeEye: Inflammation- Inflammation- Conjunctivitis, Pain, Pain,
CataractCataractIMUNITY: IMUNITY: increases.increases. OOverexposureverexposure - -
decreasesdecreases
1. Avoid tanning newborns and small children2. Avoid tanning between 10 a.m.- 2 p.m, when
intensity of Sun light is the highest 3. Always take sunscreens- wear glasses with
UVA and UVB factors, cover head by wide hats, protect body with summer dress, and use grease without perfums
4. SUNNSCREENS must contain both UV-A and UV B protecting factors (at least No 20 for level of Sun radiation)
5. Do not tan when taking remedies (e.g. antibiotics, sulfonamids, etc.)
6. Avoid visit solaria frequently - mainly persons with blond hair and light colored skin - do it with care!
7. Skin has its own „memory“ and re-members its burning by UV-light overexposure!
8. Burning of skin in childhood is very dangerous, leading to cancer in adult age, as well !
9. Take into account the Solar index
It is an electromagnetic (elmg.)radiation with frequencies btw. 300-3000 MHz, and λ = 1 - 0.1m
Is kind of non-ionizing radiation Is used at TV and Mobile Transmissions Mobile Phones work mostly under
frequency 900 and 1800 MHz. Mobile phone is small transceiver,
periodically connecting by radiowaves with Basic Mobile Station (BMS are placed on the top of hills, on the roofs, etc.)
The intensity of electromagnetic radiation in a vicinity of BMS is very high and danger for body
During calling EM radiation from mobile spre-ads to an environment as a radiosignal. The weaker is a received signal ( e.g. in car, train, or in buildings of steel and concrete) the higher is an intensity of emitted EM radiation. This radiation affects the head, ear, neck also the digits and hand of calling person on the side where a phone is taken by hand.
The depht of penetration of mobile radiation to tiss-ues is 1-2 cm (affecting mostly the brain structu-res).
The index for Specific Rate of Absorbtion (SAR ) for brain tissue was established. N= 1.6- 2.0 (W.kg-1)
For a particular value of SAR in different types of phones see the box where the mobile is stored.
The intensity of mobile radiation is low (2 W), however in brain, the intensity may be add together (summated) above normal value of SAR. Thus,the effects depend both on an intensity of mobile EM radiation and a time of calling (exposure)
1. Thermal Effects-Thermal Effects- passing the tissue radiowaves create heat - temperature within the brain rises up ( approx. 0.10 C during 12 min. time of phone call), and this, in turn may damage the neurons. Disorders of the optic and cochlear nerves were also published lately. Also a lower production of hormon melatonine was found. Subjectivelly, persons are complainted on : burning and itching of skin with erythema, some feeling of heat in the ear, bad concentration, sleeping disorders, etc.
2.2. Non Thermal Effects-Non Thermal Effects- to-date mechanisms are obscure, however scientists presume possibility for appearance of brain cancer e.g. astrocytoma (with location at the side of head, that is directly touched by phone)
- Buy only phones with SAR <1.6 (W.kg-1):look for SAR number being placed on the box
- Do not call when driving or travelling by train (i.e. avoid do make calls at all places with low signal !)
- Do not call over 2 minutes, as well. Rather use „hands free“ set.
- Do not touch the head with an antena - Do not allow children ( at least till 6
years of age) to use and make calls from mobiles
- In patients with cardiostimulator (pacemaker) store the mobile in pocket at least 20 cm from pacemaker and heart (usually on an opposite side of body)
Alpha particles Beta particles Gamma rays (or photons) X-Rays (or photons) Neutrons
Alpha Particles: 2 neutrons and 2 protonsThey travel short distances, have large massOnly a hazard when inhaled
Ionizing Radiation
Beta Particles: Electrons or positrons having small mass and variable energy. Electrons form when a neutron transforms into a proton and an electron or:
Gamma Rays (or photons): Result when the nucleus releases
Energy, usually after an alpha, beta or positron transition
X-Rays: Occur whenever an inner shell orbital electron is removed
and rearrangement of the atomic electrons results with the release of
the elements characteristic X-Ray energy
Neutrons: Have the same mass as protons but are uncharged
They behave like bowling balls
Atoms are composed of smaller particles referred to as:
• Protons
• Neutrons
• Electrons
Atoms are composed of smaller particles referred to as:
• Protons
• Neutrons
• Electrons
Ionizing radiation is produced by unstable atoms. Unstable atoms differ from stable atoms because they have an excess of energy or mass or both.
Unstable atoms are said to be radioactive. In order to reach stability, these atoms give off, or emit, the excess energy or mass. These emissions are called radiation.
Ionizing radiation is produced by unstable atoms. Unstable atoms differ from stable atoms because they have an excess of energy or mass or both.
Unstable atoms are said to be radioactive. In order to reach stability, these atoms give off, or emit, the excess energy or mass. These emissions are called radiation.
or X-
rayneutron
Ionizing Radiation
alpha particle
beta particle
Radioactive Atom
X-ray
gamma ray
Protons
Alpha Particles
Beta Particles
Positron Particles
Neutrons
Gamma Rays
X-Rays
Causes breaks in one or both DNA strands or;
Causes Free Radical formation
Americium-241= Diagnose thyroid disorders, smoke detectors.
Cesium-137= Cancer treatment. Iodine-125,131= Diagnosis &
treatment liver, kidney,heart, lung and brain.
Technetium-99m=Bone and brain imaging; thyroid and liver studies; localization of brain tumors.
Americium-241= Diagnose thyroid disorders, smoke detectors.
Cesium-137= Cancer treatment. Iodine-125,131= Diagnosis &
treatment liver, kidney,heart, lung and brain.
Technetium-99m=Bone and brain imaging; thyroid and liver studies; localization of brain tumors.
Terminology:
• Exposure rate = amount radiation possible to receive per unit time.
• Dose = total amount of radiation received.
Terminology:
• Exposure rate = amount radiation possible to receive per unit time.
• Dose = total amount of radiation received.
Early risk associated with use of ionizing radiation
skin erythema dose - 25yrs 1928 - ROENTGEN introduced by ICRP
Pronounced rent’gen with a hard “g” Limitations
• only applies to photons• only applies in air• only applies to energies less than 3 MeV
Named after Wilhelm C. Roentgen (thus the abbr... is capital “R”)
1 rad = 1 Roentgen
The unit of dose equivalent for any type of ionizing radiation absorbed by body tissue in terms of estimated biological effect - Unit of dose equivalent
Dose in health record is in units of rem
1 rem = 1 Roentgen
Roentgen Equivalent Man
The specific value that accounts for the ability of different types of ionizing radiation to cause varying degrees of biological damage• X-rays, gamma rays, & beta particles 1• Neutrons & High energy protons 10• Alpha Particles 20
Radiation hazard does not solely depend on the activity. It also depends on the type of decay (alpha, beta, photon, etc.)
Named in honor of Pierre Curie
International Units have replaced the RAD and REM
GRAY (Gy) = 100 RADSIEVERT (Sv) = 100 REM
Same Quality Factors apply to the Sv
Curie (Ci) = 2.22 E12 dpm or 3.7E10 dps
Becquerel (Bq) = 1 dps Maximum Dose/year = 5 REM or 50
mSv Maximum Dose/year for Declared
Pregnant Woman & Minors= 0.5 REM or 5 mSv
0-150 rem—No or minimal symptoms 150-400 rem—Moderate to severe
illness 400-800 rem—Severe illness deaths
start above 500 rem Above 800 rem—Fatal
***Acute whole body doses
Activity Typical DoseSmoking 280 millirem/year
Radioactive materials use in a UM lab
<10 millirem/year
Dental x-ray10 millirem per x-ray
Chest x-ray 8 millirem per x-ray
Drinking water 5 millirem/yearCross country round trip by air
5 millirem per trip
Coal Burning power plant0.165 millirem/year