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 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: Internal Hazard
C-14: Energy max = 0.26 Mev: Internal Hazard
S-35: Energy max = 0.17 Mev: Internal Hazard
P-32: Energy max = 1.7 Mev: Internal 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 photons
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 Produced as an interaction with matter or by
x-ray tube emission
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
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 of REM
H = quality factor (Q) times the absorbed dose (D)
• Q equals 1 for beta, gamma and x-rays
• 5-20 for neutrons
• 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 (R) 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
State of Maine required dose limit: 5 rem whole body (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 pregnant women: 0.5 rem for the term of pregnancy
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
Ingested radioisotopes may accumulate in certain organs
Radium and Stroncium in the bones and Iodine in the thyroid
However, is useful in diagnostic procedure
Technetium-99m
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
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
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 increases with exposure
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.
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 as 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
FACILITIES AND
EQUIPMENT
REQUIRED
TYPE OF LABORATORY
TYPE A TYPE B TYPE C
Low-level survey
meter
YES YES YES
High level survey
meter
YES YES NO
Wipe test counting
instrument
YES YES YES
Shielded isotope
storage areas or
containers
YES YES YES
Shielded waste areas YES YES NO
Shielded L-blocks YES YES NO
Fume Hood YES YES NO
Caution signs YES YES YES
Personnel monitoring YES* YES* YES*
* Depending on isotopes being handled and current approved policies.
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
250 microcuries(uCi)
0.000250 Curies
9.25 megabecquerels
9,250.00 dps
Uranyl Acetate is composed of 99% U238 and <1% U235
Is radioactive and highly toxic
Emits Alpha, Beta, and minute Gamma energies
Used primarily for staining of cells to be viewed using Electron Microscopy
Uranium (VI) Oxide Depleted uranium - U238 Used for staining of cell
structures Is radioactive and highly toxic Emits Alpha, Beta, and minute
Gamma energies
Faxitron X-RAY system
Uses X-ray tube to generate x-ray
Door is double interlocked to prevent x-ray activation when open
Radiation exposure levels depend on distance from tube and energy setting.
Niton XRF Analyzer Hand held x-ray emitting device. Mounts to shielded fixture for
stand alone x-ray examination of samples
Can be “trigger” or button activated menu operated.
Geiger Mueller (G-M)
Gamma and x-ray
High energy beta particles
Sodium Iodide Detector
Gamma and x-ray
Not currently in use
Used for beta, gamma, and x-ray emitting isotopes
Best for P-32, S-35 and C-14
Good for I-125, Cr-51, & U-238
Not good for H-3
Check calibration date
Calibrated annually Check batteries Replace batteries if
necessary Confirm operational
using radioactive source on side of device.
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 – 3mg
Place in scintillation counter
Set scintillation counter to detect radioisotopes used in laboratory
Add 3ml scintillation fluid to vials
Place Q-tip end in scintillation vial
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 For U-238 (Uranyl Acetate & Uranium Oxide),
conduct wipe test after each weighing or handling of substance.
RSO conducts monthly wipes of Core Lab
<200 dpm/100cm2 in unrestricted areas (hallways, offices, and labs not licensed for radioactive material)
<1,000 dpm/100cm2 in restricted 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 spreading of material
Laboratory coat
Gloves
Safety Glasses
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
Required when possibility of receiving greater than 10% of exposure limit. Not required for all individuals working with radioactive materials at USM currently. Issued to employees to record exposure. Never brought home. Return promptly upon receiving new dosimeter.
Records occupational exposure.
Records exposure from gamma, x-ray and high energy beta
Not to be loaned out.
Should never be worn outside of work.