Radiation Safety Training

Transcription

1 Radiation Safety Training

2 Radioactivity is the property of certain nuclides to spontaneously emit particles and/or waves (photons) These nuclides are called radionuclides, radioisotopes, or just isotopes The nucleus in the atom of a radioisotope is unstable To become stable, it releases particles or rays

3 Radiation is the emission and propagation of energy in the form of particles or waves through a medium Particulate radiation includes alpha, beta, and neutron radiation Wave radiation include light, UV radiation, gamma radiation, and x-rays

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5 Particulate: alpha, beta and neutron Wave: gamma and x-ray (photons)

6 Particulate radiation consisting of an electron Relatively light particle moving at up to 99% the speed of light Travels deep into matter depending upon its energy An internal or external health hazard depending on the isotope Plexiglas shielding

7 H-3: Energy max = 0.19 Mev: Internet Hazard C-14: Energy max = 0.26 Mev: Internet Hazard S-35: Energy max = 0.17 Mev: Internet Hazard P-32: Energy max = 1.7 Mev: Internet and external hazard

8 Particulate radiation consisting of two protons and two neutrons (helium nucleus) Emitted by heavy nuclides (uranium, thorium, radium, and radon) Relatively heavy particle moving at 80% The speed of light Does not travel very deep in matter Internal health hazard

9 A wave radiation consisting of a photon Travels at the speed of light Highly energetic Deeply penetrating in matter Lead shielding required depending on the energy of the radiation Internal and external hazard Cr-51 (0.32 MeV), I-125 (0.04 MeV)

10 A wave radiation traveling at the speed of light and similar to gamma radiation Deeply penetrating in matter Lead shielding required depending on the energy of the radiation Internal and external hazard Also produced by x-ray machine

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14 Literally: breaking radiation Electromagnetic radiation produced when an electrically charged particle is slowed down by the electric field of an atomic nucleus Example: the electron emitted by a P-32 atom will interact with lead to give off an x-ray

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16 The Curie: abbreviated Ci 1 Ci = 37E10 disintegrations per second 1 Ci = 2.2E12 disintegrations per minute 1 Ci = 1000 millici 1E6 micro Ci

17 The Becquerel: abbreviated Bq International Unit 1 Bq = 1 disintegration per second 1 Bq = 2.7E-11 Ci Also megabq and gigabq

18 250 microcuries Curies 9.25 megabecquerels 9, dps

19 A disintegration is the same as a transformation. For example when P-32 disintegrates it is actually transforming to S-32, which is a stable isotope. Some radioisotopes transform to another radioisotope, which is also radioactive. Example: Radium transforms to Radon

20 The half life of a materials is the time required for half of the radioactive atoms present to decay The half life is a distinct value for each radioisotope Radiological or physical half life Biological half life

21 Nitrogen 17: 4.14 seconds Phosphorus-32: 14.3 days Tritium: 12.3 years Carbon-14: 5,730 years Uranium: 4,500,000,000 years

22 You receive a shipment of 250 uci of P-32 The half life of P-32 is 14.3 days If you do not use the P-32 until 14.3 days after receiving the material, you will only have 125 uci left If you wait 28.6 days, you will only have 62.5 uci left After 10 half lives, there will only be 0.24 uci left

23 The Roetgen: named after discoverer of the x-ray Ability of photons to ionize air Applies only to photons in air Equal to 2.58E-4 Coulombs/Kg

24 Absorbed Dose (D) D in Units of Rads Energy actually depositied in matter 1 Rad 100 ergs of deposited energy per gram of absorber International Unit: 1 Gray 100 Rads

25 Dose Equivalent (H) H in units in REM H quality factor (Q) times the absorbed dose (D) Q equals 1 for beta, gamma and x-rays, 5-20 for neutrons, and 20 for alpha International Unit 1 Sievert = 100 REM

26 Anticipate only beta, gamma and x-ray emitters Quality factor equals 1 Therefore a Roetgen equals a Rad equals a Rem Exposure reports in REM

27 Natural and man-made sources of radiation everybody is exposed to in their daily lives. Can show up as exposure on an individuals film badge if not corrected with a control badge Typically 40 to 50 mrem per month 620 mrem/yr according to NCRP Report 160 published in 2009

28 Terrestrial: rocks, soil, and radon Cosmic: the sun and outside the solar system Man-made: medical, consumer goods and nuclear power

29 Uranium and daughter products in rocks and soil (U238 Ra226 Rn222 Po218) Radon in houses Pb-210 and P0-210 in tobacco Tritium in the atmosphere Radon in domestic water Potassium-40 in foods

30 Smoke detectors Coleman lantern mantles Airport luggage scanners Fiesta ware Static eliminators Building material Luminous watches

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33 Terrestrial (Cosmic) Radon Medical Consumer products 81 mrem 229 mrem 298 mrem 12 mrem Total 620 mrem

34 Data based on large exposures to individuals in the first half of the century Exposure to radiation in excess of 50 rads over a short period of time Exposure to individuals at nuclear power plants, hospitals, and research orders of magnitudes smaller All occupational exposure limited by city, state, or federal regulations

35 Researchers first working with radioactive material and radiation producing devices Early use of radiation in the medical profession Radium dial painters Exposure to atomic bomb detonation Radioactive material in medical research

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40 Damages cells by breaking the DNA bonds Chemical or mechanical reaction Chemical: Generates peroxides which can attack the DNA Mechanical: Direct hit to the DNA by the radiation Damage can be repaired for small amounts of exposure

41 Muscle Radioresistant Stomach Radiosensitive Bone Marrow Radiosensistive Human Gonads Very Radiosensitive

42 Acute exposure: large dose in short period Acute Effects: symptoms arise soon after exposure (nausea, vomiting, loss of hair, blood changes, etc) Chronic exposure: small doses over long period Latent Effects: symptoms appears some time, perhaps years, after an exposure (cataracts, cancer, genetic effects)

43 If an individual receives a dose in excess of 100 Rem in a short period of time, he/she will experience acute effects (changes in blood composition observable).

44 Skin: early researchers using x-rays Leukemia: Early radiologists and bomb survivors Bone Cancer: Radium dial painters Lung Cancer: Miners in radium mines

45 The amount of time over which the dose was received The type of radiation The general health of the individual The age of the individual The area of the body exposed

46 The level of exposure is related to the risk of illness While the risk for high levels of exposure is apparent, the risk for low levels is unclear Estimated that 1 rem of exposure increase likelihood of cancer by 1 in 10,000 Though the likelihood of cancer in ones life time is 1 in 3 from all other factors

47 No direct evidence of increased birth defects or childhood leukemia or other cancers from exposure at universities May extrapolate from high-dose data, but may subject to uncertainty The incident from radiation exposure would be masked by the natural incidence due to all other factors.

48 In embryo stage, cells are dividing very rapidly and undifferentiated in their structure More sensitive to radiation exposure Especially sensitive during the first 2 to 3 months after conception Risk of cancer and retardation

49 State of Maine required dose limit: 5 rem WB USM policy requires that action be taken at: 0.5 rem Anticipated exposure at USM is far below the 0.5 rem amount Exposure limit to the embryo/fetus: 0.5 rem to a women who has declared she is pregnant and avoid month-to-month variation in the dose.

50 Declared Pregnancy Ordering Radioactive Material Receipt of Radioactive Material With warning labels Without warning labels Tracking Material Radioactive Waste Transfer of Material to another institution

51 Contact the RSO if you know or suspect your pregnant Issued a special dosimeter during the term of the pregnancy Limit total dose to 0.5 rem with a monthly dose of 0.05 during the term of the pregnancy Follow all mandatory procedures and use protective devices Must continue to perform duties unless alternative arrangements are made with PI If concerned may resign or request a leave of absence Remains in effect until the declared pregnant woman withdraws the declaration in writing.

52 Patient exposure for treatment and therapy Patient exposure in diagnostic procedures Radiation exposure to nuclear power plant workers Radiation exposure to radiologist, radiological technicians, and nurses Radiation exposure to medical research staff

53 Time: minimize the time you are exposed to radiation Distance: Maintain the maximum distance possible between yourself and the source of the ionizing radiation. Shielding: Protect yourself with shielding when you are working with ionizing radiation.

54 Reduce time Increase distance - inverse square law - dose a = dose b x(r b/r a ) 2 Use appropriate shielding

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56 At one (1) foot the dose rate from a I-125 source is 10 mrem/hour. If you stand back to two (2) feet from the source, the dose rate will decrease to 2.5 mrem/hour. If you stand back three (3) feet from the source, the dose rate will be 1.1 mrem/hour.

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58 Lead for gamma and x-ray emitters such as I- 125, Cr-51, Na-22, Co-60, etc. Plexiglass for high energy beta emitters such as P-32 and Sr-90

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63 Low-level survey meter High-level survey meter Wipe test counting instrument Shielded storage Shielded waste container Shielded L-block Fume hood Caution signs Personal monitoring

64 Type A Laboratory: Specially designed for handling large activities of highly radioactive materials. Type B Laboratory: Specially designed radioisotope laboratory. Type C Laboratory: Good quality chemical laboratory

65 RADIOTOXICITY OF RADIONUCLIDES TYPE OF LABORATORY REQUIRED TYPE A TYPE B TYPE C VERY HIGH 10 mci 10 uci - 10 mci < 10 uci HIGH 100 mci 100 uci mci < 100 uci MODERATE 1 Ci 1 mci - 1 Ci < 1 mci LOW 10 Ci 10 mci - 10 Ci < 10 mci

66 RELATIVE RADIOTOXICITY OF RADIONUCLIDES VERY HIGH HIGH MODERATE LOW Am-243 Ac-228 Au-198 Co-58m Cf-249 Bi-207 Be-7 Cs-125 Cm-244 Ce-144 C-14 Ge-71 Pa-231 Cl-36 Cr-51 H-3 Pb-210 Co-56 Gd-153 Kr-85 Po-210 Co-60 La-140 Nb-97 Pu-238 Hf-181 Na-24 O-15 Ra-226 I-125 P-32 Os-191m Ra-228 I-131 Ru-103 Rb-87 Th-227 Ir-192 S-35 Rh-103m Th-232 Na-22 Sc-48 Tc-99m U-238 Sb-125 Sr-91 Xe-131m Zr-95 Te-125m Cs V-48 W-187 Y-90 Zn-65 Zn-69m

67 Definition: Radioactive material in an undesired location Undesired locations: surfaces, skin, internal, airborne Types: removable and fixed

68 A survey meter may be used to detect large quantities of high energy beta and gamma emitters on a surface For smaller quantities of contamination on surfaces and low energy beta emitters, use the wipe test method

69 Choose equipment and surfaces to wipe Use a filter paper or Q-tip Moisten the paper or Q-tip Wipe approximately 100 cm 2

70 Place filter paper or Q-tip in scintillation vial Add scintillation fluid Place in scintillation counter Set scintillation counter to detect radioisotopes used in laboratory

71 Routinely, weekly for all radioisotopes Biweekly for P-32, S-35 and C-14 in amounts greater than 10 mci and less than 100 mci Weekly for P-32, S-35 and C-14 greater than 100 mci Biweekly for H-3 greater than 100 mci

72 <200 dpm/100cm 2 in unrestricted areas (hallways, offices, and labs not licensed for radioactive material) <1,000 dpm/100cm 2 in unrestricted areas (radioisotope laboratories) <1,000 dpm/100cm 2 immediately clean up to below 1,000 dpm/100cm 2 It is strongly recommended that you always decontaminate to as low as practicable

73 Radioactive containers (stock, flasks, beakers) Laboratory benches Laboratory apparatus and equipment Radioactive waste containers Refrigerator door handles Laboratory door handles Gloves and laboratory coats

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79 Work in areas designated for radioactive material Use absorbent pads Wear appropriate protective clothing Do not spread contamination on gloves to other items or areas in lab Remove gloves prior to leaving laboratory Avoid spilling or aerosols

80 Laboratory coat Gloves Safety Glass Dosimetry (P-32 or gamma and x-ray emitters)

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84 Ensure that there is nothing obstructing air flow Confirm that the flow rate for the fume hood has been checked Check that it is operational Set the sash at the appropriate level

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86 Follow the correct experimental protocol Wear personal protective equipment If required, use a fume hood No eating, drinking or applying cosmetics Clean up spills promptly Routinely monitor work area Secure radioactive material

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88 Ingested radioisotopes may accumulate in certain organs Radium on the bones and Iodine in the thyroid However, is useful in diagnostic procedure Technetium-99m

89 Geiger Mueller (G-M) - Gamma and x-ray - High energy beta particles Sodium Iodide Detector - Gamma and x-ray

90 Used for beta, gamma and x-ray emitters Best for P-32, S-35 and C-14 Good for I=125 and Cr-51 Not good for H-3

91 Check calibration date Calibrated annually Check batteries Replace batteries if necessary Confirm operational using radioactive material

92 Used for gamma and x-ray emitters I-125 and Cr-51 Also x-ray units Not used for beta emitters such as P-32

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94 Should be kept less than 0.1 mrem/hour Use principle of ALARA Decontaminate area as needed Shield sources as needed Request a waste pickup to remove Hot waste

95 Required when possibility of receiving greater than 10% of exposure limit. Required for all individuals working with radioactive materials at USM. Worn by individual to who it is issued. Never bring home. Return promptly upon receiving new dosimeter

96 Monitors occupational exposure. Worn for 3 months. Typically, monitors for gamma, x-ray and high energy beta Do not loan out. Promptly return after receiving new one.

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98 Monitors exposure to the hands. Used for high energy beta and x- ray radiation. Worn when handling > 500 mci of P-32 or x-ray machines