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Radiation Safety Training
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
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
Particulate: alpha, beta and neutron
Wave: gamma and x-ray (photons)
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
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
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
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)
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
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
The Curie: abbreviated Ci
1 Ci = 37E10 disintegrations per second
1 Ci = 2.2E12 disintegrations per minute
1 Ci = 1000 milliCi – 1E6 micro Ci
The Becquerel: abbreviated Bq
International Unit
1 Bq = 1 disintegration per second
1 Bq = 2.7E-11 Ci
Also megaBq and gigaBq
250 microcuries
0.000250 Curies
9.25 megabecquerels
9,250.00 dps
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
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
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
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
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
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
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
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
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
Terrestrial: rocks, soil, and radon
Cosmic: the sun and outside the solar system
Man-made: medical, consumer goods and nuclear power
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
Smoke detectors
Coleman lantern mantles
Airport luggage scanners
Fiesta ware
Static eliminators
Building material
Luminous watches
Terrestrial (Cosmic)
Radon
Medical
Consumer products
Total
81 mRem
229 mRem
298 mRem
12 mrem
620 mRem
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
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
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
Muscle Radioresistant
Stomach Radiosensitive
Bone Marrow Radiosensistive
Human Gonads Very Radiosensitive
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)
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).
Skin: early researchers using x-rays
Leukemia: Early radiologists and bomb survivors
Bone Cancer: Radium dial painters
Lung Cancer: Miners in radium mines
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
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
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.
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
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.
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
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.
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
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.
Reduce time
Increase distance
- inverse square law
- dosea = dosebx(r b/ra)2
Use appropriate shielding
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.
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
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
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
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 - 100 mCi < 100 uCi
MODERATE ≥1 Ci 1 mCi - 1 Ci < 1 mCi
LOW ≥10 Ci 10 mCi - 10 Ci < 10 mCi
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 - 137 V-48
W-187
Y-90
Zn-65
Zn-69m
Definition: Radioactive material in an undesired location
Undesired locations: surfaces, skin, internal, airborne
Types: removable and fixed
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
Choose equipment and surfaces to wipe
Use a filter paper or Q-tip
Moisten the paper or Q-tip
Wipe approximately 100 cm2
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
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
•<200 dpm/100cm2 in unrestricted areas (hallways, offices, and labs not licensed for radioactive material)
•<1,000 dpm/100cm2 in unrestricted areas (radioisotope laboratories)
•<1,000 dpm/100cm2 immediately clean up to below 1,000 dpm/100cm2
•It is strongly recommended that you always decontaminate to as low as practicable
Radioactive containers (stock, flasks, beakers)
Laboratory benches
Laboratory apparatus and equipment
Radioactive waste containers
Refrigerator door handles
Laboratory door handles
Gloves and laboratory coats
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
Laboratory coat
Gloves
Safety Glass
Dosimetry (P-32 or gamma and x-ray emitters)
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
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
Ingested radioisotopes may accumulate in certain organs
Radium on the bones and Iodine in the thyroid
However, is useful in diagnostic procedure
Technetium-99m
Geiger Mueller (G-M)
- Gamma and x-ray
- High energy beta particles
Sodium Iodide Detector
- Gamma and x-ray
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
Check calibration date
Calibrated annually
Check batteries
Replace batteries if necessary
Confirm operational using radioactive material
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
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
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
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.
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