Non-Ionizing Radiation

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Non-Ionizing Radiation. I o n i z i n g. N o n – I o n i z i n g. - PowerPoint PPT Presentation

Transcript of Non-Ionizing Radiation

  • includes all kinds of electromagnetic radiations with frequencies < 1015 Hz and wavelengths = 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.-Rays X-rays UV VL IR MW R a d i o I o n i z i n gN o n I o n i z i n g

  • UV Light is invisible radiation with = 100- 400 nm, Sources: natural (Sun), artificial (mercury lamps )

    Classification:UVA- long wave,black-tanning light = 315 - 400 nmUVB- medium wave,inflamatory = 280 - 315 nmUVC- short wave,killing germs = 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 O2Ozone O3 and O2 lower the intensity of UVA and UVB lights and totally absorb UVC lightOzone holes- increase a level of UV radiation!

  • Skin: Erythema- early red coloured skin inflammation(appears after 2-3 hours) Tanning (delayed pigmentation, because production of melanine.( it starts approx. 24- 48 hours after expo- sure) Vitamine D production Skin Aging (Wrinkles, Dry skin, Skin cancer-melanoma)Eye: Inflammation- Conjunctivitis, Pain, CataractIMUNITY: increases. Overexposure - decreases

  • Avoid tanning newborns and small childrenAvoid tanning between 10 a.m.- 2 p.m, when intensity of Sun light is the highest Always take sunscreens- wear glasses with UVA and UVB factors, cover head by wide hats, protect body with summer dress, and use grease without perfumsSUNNSCREENS must contain both UV-A and UV B protecting factors (at least No 20 for level of Sun radiation)Do not tan when taking remedies (e.g. antibiotics, sulfonamids, etc.)Avoid visit solaria frequently - mainly persons with blond hair and light colored skin - do it with care! Skin has its own memory and re-members its burning by UV-light overexposure!Burning of skin in childhood is very dangerous, leading to cancer in adult age, as well !Take into account the Solar index

  • It is an electromagnetic (elmg.)radiation with frequencies btw. 300-3000 MHz, and = 1 - 0.1mIs kind of non-ionizing radiation Is used at TV and Mobile TransmissionsMobile 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 ( 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- 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. 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
  • Alpha particlesBeta particlesGamma rays (or photons)X-Rays (or photons)Neutrons

  • Alpha Particles: 2 neutrons and 2 protonsThey travel short distances, have large massOnly a hazard when inhaledIonizing 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:ProtonsNeutronsElectrons

  • 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

  • Radioactive AtomX-raygamma ray

  • Protons

    Alpha Particles

    Beta Particles

    Positron Particles

  • Neutrons

    Gamma 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.

  • Terminology:Exposure rate = amount radiation possible to receive per unit time.Dose = total amount of radiation received.

  • Early risk associated with use of ionizing radiationskin erythema dose - 25yrs1928 - ROENTGEN introduced by ICRP

  • Pronounced rentgen with a hard gLimitationsonly applies to photonsonly applies in aironly 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 equivalentDose in health record is in units of rem1 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 damageX-rays, gamma rays, & beta particles 1Neutrons & High energy protons 10Alpha 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 dpsBecquerel (Bq) = 1 dpsMaximum Dose/year = 5 REM or 50 mSvMaximum Dose/year for Declared Pregnant Woman & Minors= 0.5 REM or 5 mSv

  • 0-150 remNo or minimal symptoms150-400 remModerate to severe illness400-800 remSevere illness deaths start above 500 remAbove 800 remFatal

    ***Acute whole body doses

  • **A gamma particle is a photon. It is produced as a step in a radioactive decay chain when a massive nucleus produced by fission relaxes from the excited state in which it first formed towards its lowest energy or ground-state configuration. * How this can be dangerous How we can protect ourselves- Types will be discussed later

    *- Symbols*- Radiation studies began in 1895 with the discovery of x-rays

    - Early physicist and therapist eventually knew that ionizing radiation was hazardous, however, there was no definite way to quantify the dose or damage. No suitable unit. Many injuries and deaths.

    - For therapy-dose making skin red

    - International Committee of Radiation Protection*- 4 bullets will transition 1 by 1

    - Imphasize abbv. rules

    - Ionizations produced in air*- 3 bullets will transition 1 by 1

    - 1953

    - dose relates to an irradiated medium

    - 1 Roentgen equivalent to 95 ergs/g of tissue

    - gamma vs. neutron (LET) *- 5 bullets will transition 1 by 1

    - For biological damage (tissue) purposes

    *- Table Pg. 5

    - Function of LET

    - Higher LET - Higher Q*- 2 bullets will transition 1 by 1

    - Transformation of the nucleus- DECAY

    - Decay per unit time - Activity

    - Beta(H3) vs. Photon(Co-60)

    - A transformation may produce more than one photon/particle emmision (dependent on radionuclide-Table Vol. II, Tab M)

    *0-150 Perhaps increased cancer with long latency\\\150-400 increased cancer risk---400-800 GI damage at higher rates