Transcript Albert Einstein College of Medicine of Yeshiva University

University of Notre Dame
Department of Risk Management and
Safety
2013 Radiation Safety
Refresher Training
INTRODUCTION
• Lessons 1-5 will provide a review of some general
knowledge of radiation with which all radioactive
material and radiation producing machines should
be familiar.
• Lessons 6-14 address specific safety practices and
procedures applicable to laboratories at Notre Dame
Lesson 1
Forms of Radiation
Forms of Ionizing Radiation
Ionizing radiation includes emissions with energies
greater than 20 electron volts that cause ionizations
when interacting with matter.
Sources of ionizing radiation at Notre Dame
include:
Particulate Radiation
Photon Radiation
− Alpha
− Gamma
− Beta
− X-Ray
Particulate Radiation
• ALPHA RADIATION
– Consists of two protons and
two neutrons (helium nucleus)
– Massive size, moving at 80%
the speed of light
– Internal Hazard
• BETA RADIATION
– Consists of an electron
– Very small size moving at up
to 99% the speed of light
– Hazard depends on decay
energy of isotope
Examples of Beta Emitters
•
•
•
•
H-3:
C-14:
S-35:
P-32:
Energy max = 19 Kev: Internal Hazard
Energy max = 160 Kev: Internal Hazard
Energy max = 170 Kev: Internal Hazard
Energy max = 1700 Kev: Internal and
external hazard
− The lower energy beta emitters are less penetrating and
present less of a hazard. The concerns with these
isotopes is primarily associated with internal exposure
due to ingestion, inhalation, or skin absorption
− Higher energy beta emitters are more penetrating and
present both internal and external hazards
Photon Radiation
• GAMMA RADIATION
– A wave radiation consisting of
a photon
– Travels at the speed of light
– Created in the nucleus of the
atom
• X-RAYS
– A wave radiation consisting of
a photon
– Travels at the speed of light
– Created in the electron shell
of the atom
Examples of Gamma Emitters
• I-125: Energy max = 35 Kev:
Internal/External
Hazard
• Cs-137: Energy max= 662 Kev: Internal/External
Hazard
− Gamma Emitters have no mass and are very
penetrating
− All gamma emitting isotopes and are considered
both internal and external hazards
Bremsstrahlung Radiation
when an electrically charged particle
is slowed down by the electric field
of an atomic nucleus
− Example: The beta particle emitted
by a P-32 atom will interact with lead
to give off an x-ray
− Bremsstrahlung production must be
considered when planning the
shielding of high energy beta
emitters
e-
Xray
0
0
− Literally: breaking radiation
− Electromagnetic radiation produced
e-
Lesson 2
Units of Radioactivity
Units of Radioactivity
The Becquerel (Bq) - International Unit
1 Bq = 1 disintegration per second
1 MBq = 1,000,000 disintegrations per second
1 GBq = 1,000,000,000 disintegrations per second
The Curie (Ci) – Commonly used in the United States
1 Ci = 3.7E10 disintegrations per second
1 Ci = 2.2E12 disintegrations per minute
1 Ci = 1000 millicurie (mCi) = 1,000,000 microcurie (uCi)
1 Bq = 2.7E-8 mCi
Units of Radioactivity
RAD
• The RAD is the unit commonly used in the United
States for Absorbed Dose (D)
• It is determined by the Energy that is actually
deposited in matter
• 1 Rad = 100 ergs of deposited energy per gram of
absorber
Gray
• International Unit for Absorbed Dose
1 Gray = 100 Rads
Units of Radioactivity
REM
• The REM is the unit commonly used in the United
States for the Dose Equivalent
• Determined by Multiplying the absorbed dose (D)
times a quality factor (Q)
• Q equals 1 for beta, gamma and x-rays,
5-20 for neutrons, and 20 for alpha
Sievert
• International Unit for absorbed dose
1 Sievert = 100 REM
Units of Radioactivity
• Most labs at Notre Dame will use only beta, gamma
and/or x-ray emitters
The Quality factor for these forms of radiation is
equal to 1
Therefore the Rad is equal to the Rem
If your lab is one of the few using alpha, remember that
the QF is 20. Therefore, one Rad of alpha is equal to
20 Rem.
• Exposure reports are documented in mREM
1 REM = 1,000 mREM
Lesson 3
Half Life
Half Life
• The half life of a materials is the time required for
1/2 of the radioactive atoms to decay
• The half life is a distinct value for each
radioisotope
Half Life of Selected
Radioisotopes
•
•
•
•
•
Flourine-18:
109.8 minutes
Phosphorus-32:
14.3 days
Tritium:
12.3 years
Carbon-14:
5,730 years
Uranium:
4,500,000,000 years
Example of Half Life
• You receive a shipment of 250 µCi 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 µCi
left
– If you wait 28.6 days, you will only have 62.5 µCi
left
• It is important to consider the half life of the
radioisotope when planning a study that includes
the use of radioactive materials
Lesson 4
Background Radiation
Background Radiation
• Natural and man-made sources of radiation
everybody is exposed to in their daily lives
• Typically 20 to 30 mRem per month
How Might I Be Exposed?
Average Annual Exposure to the
General Public
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•
•
•
Cosmic
Terrestrial
Radon
Medical
• Total
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•
•
•
30 mRem
40 mRem
230 mRem
90 mRem
• 390 mRem
Lesson 5
Biological Effects & Risk
Biological Effects
• Data is largely based on high exposures to
individuals within the first half of the 20th century
• Biological effects occur when exposure to radiation
exceeds 50 rads over a short period of time
• All occupational exposures are limited by city,
state, or federal regulations
Radiation Damage
• Mechanical: Direct hit to the DNA by the
radiation
- Damages cells by breaking the DNA bonds
• Chemical: Generates peroxides which can
attack the DNA
Damage can be repaired for small amounts of
exposure
Radiosensitivity
•
•
•
•
Muscle
Stomach
Bone Marrow
Human Gonads
Radioresistant
Radiosensitive
Radiosensitive
Very Radiosensitive
Radiation Effects
• Acute Effects: Nausea, Vomiting, Reddening of
Skin, Hair Loss, Blood Changes
• Latent Effects: Cataracts, Genetic effects, Cancer
Dose Required for Acute Effects
If an individual receives a dose in excess of 50
Rem (50,000 mRem) in a short period of time,
he/she will experience acute effects
Risk of Cancer
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
It is estimated that 1 rem TEDE of exposure
increase likelihood of cancer by 1 in 1000
The likelihood of cancer in ones life time is
1 in 3 from all other factors
Factors Affecting Risk
• 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
Lesson 6
Occupational Exposure
What are the Occupational
Exposure Limits ?
•
•
•
•
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Whole Body
Extremities
Skin of Whole Body
Lens of Eye
Thyroid
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•
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•
•
5,000 mRem/year
50,000 mRem/year
50,000 mRem/year
15,000 mRem/year
15,000 mRem/year
Other Occupational Limits
• ALARA - As Low As Reasonably Achievable. This is
our policy AND the NRC’s: Don’t expose yourself to
radiation any more than absolutely necessary.
Exposure to the General Public
• Annual limit of 100 mRem to individuals
• This includes anybody in the laboratory who does
not work for Notre Dame
• Examples: salesmen, vendors, family members,
etc.
Prenatal Radiation Exposure
• In the embryo stage, cells are dividing very
rapidly and are undifferentiated in their structure
and are more sensitive to radiation exposure
• Especially sensitive during the first 2 to 3 months
after conception
• This sensitivity increases the risk of cancer and
retardation
Declaring Pregnancy
– Additional dose restrictions are available for the
pregnant worker
– Receive a monthly dosimeter
– Limited to 500 mRem during the term of the
pregnancy
– Also, limited to 50 mRem per month
– DECLARATION IS STRICTLY OPTIONAL
Exposure to Minors
Individuals under the age of 18
– Must not receive an exposure greater than
10% of occupational exposure for adults
– Wholebody Exposure Limit: 500 mRem
– Minors will wear dosimeters in laboratories
licensed for radioactive material use
– Minors should not work with radioactive
material
Lesson 7
Minimizing Exposure
How Do I Protect Myself?
• Reducing the dose from any source radiation
exposure involves the use of three protective
measures:
–
TIME
–
DISTANCE
–
SHIELDING
Time
− The amount of
exposure an individual
accumulates is directly
proportional to the
time of exposure
− Keep handling time to
a minimum
Distance
− The relationship
between distance and
exposure follows the
inverse square law.
The intensity of the
radiation exposure
decreases in
proportion to the
inverse of the distance
squared
− Dose2 = Dose1 x (d1/d2)2
Shielding
− To shield against beta
emissions, use plexiglass
to decrease the
production of
bremsstrahlung radiation.
− If necessary, supplement
with lead after the
plexiglass
− To shield against gamma
and x-rays, use lead,
leaded glass or leaded
plastic
Internal Exposure
− Only a few commonly
used radionuclides at
Notre Dame present an
external exposure
potential
− All radionuclides
present a potential for
internal exposure if
taken into the body.
Entry into the body can
occur by inhalation,
ingestion, or absorption
through the skin
Minimizing Internal Exposure
• 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
Minimum Protective Equipment
• Laboratory coat
• Gloves
• Safety Glasses
• Dosimeters
Lesson 8
Regulatory Requirements
Notre Dame’s License
• Broadscope license issued by the Nuclear
Regulatory Commission
• Permits the use of radioactive material in research
and development, as well as education.
• Must be renewed every 10 years
Radiation Safety Requirements
• Radiation Safety Officer
• Radiation Safety Committee
• Approved Responsible
Investigators
• Radioisotope Users
Records to be Kept on File
In the Laboratory
- Receipt of material
- Utilization of material
(logs)
- Waste disposal
- Monthly Wipe tests
-Training verification
By Radiation Safety
-Principal Investigator
-Isotope limits
-Receipt of material
-Waste transferred
-Lab inspections
-Exposure reports
The NRC Inspectors will look
specifically for these
completed documents in the
lab Radiation Safety notebooks
which should be stored in
every radiation lab.
Records (Continued)
If radioactivity is not used or stored during a
month, a signed statement may be
substituted for a wipe test
Example of Signed Statement:
“There has been no radioactive material use
or storage in lab ____ during the month of
____”.
Radiation Safety Inspections
• Inspections are conducted at least every other
month
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Review isotope use records and wipe test records
Confirm appropriate postings and labels
Personal protective equipment and dosimetry
Shielding and survey instrument available
Contamination and radiation dose rate survey
Where Will Isotopes be Found?
• In labs labeled with “Caution Radioactive Material”
signs at the entrance
• Usually stored in freezers, refrigerators, or fume
hoods
• Waste stored in labeled containers
• Radioactive waste storage rooms
Postings and Labels
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Entrance to laboratory
Refrigerator/freezer
Equipment/instruments
Radioactive waste containers
Laboratory benches
Fume hoods for use
Labeling Containers
• All containers used for storing radioactive material
or radioactive waste must be stored in labeled
containers
• The label displays the radiation symbol with the
words “Caution Radioactive Material”
• The isotope, activity in uCi or mCi and the start
date should be included on label
Lesson 9
Radiation Detection
Detecting Radiation and
Contamination
• Personal dosimeters are used to detect the
occupational exposure to employees from external
sources of radiation
• 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
Film Badge
 Required when there is a




possibility of receiving
greater than 10% of
exposure limit
Monitors for gamma, x-ray
and high energy beta
Worn for 2 months
These are individual specific
- Do not loan out
Return promptly after
receiving a new one
Ring Dosimeter
 Monitors exposure to the


hands
Used for high energy
beta, gamma and x-ray
radiation
Worn when handling
sources like those listed
above or x-ray machines
Survey Instruments
• Geiger Mueller (G-M)
- Detects alpha, beta, and gamma
radiation
- Best option for detecting beta
contamination
• Sodium Iodide Detector
- Gamma and x-ray only
Survey Instruments
Operational Check
• Check calibration date
• Confirm calibration
date within past year
• Check batteries
• Check response to
radioactive source to
confirm that the meter
is operational
Survey Instruments
• Geiger-Mueller
Detector
– Used for beta, gamma
and x-ray emitters
– Best for P-32, S-35 and
C-14
– Will detect I-125 and
Cr-51
• Sodium-Iodine Detector
– Detects gamma and x-ray
emitters
– I-125 and Cr-51
– Do not use to detect beta
emitters
Wipe Test Method
• The Wipe Test Method is a
means of monitoring for
small amounts of
contamination
• It is the only method in
the lab for detecting H-3
• Wipe test surveys should
include both areas where
contamination is expected
to be found and areas
where it is not expected
Wipe Test
1. Choose equipment and surfaces to wipe
2. Use a filter paper or Q-tip to wipe
approximately 100 cm2.
3. Place filter paper or Q-tip in scintillation
vial and add scintillation fluid (use
enough fluid to fill at least ½ of vial)
4. Place sample in scintillation counter
5. Set scintillation counter to detect
radioisotopes used in laboratory
6. Include a standard or sample containing
a known amount of radioactive material
7. Include a background or control sample
Determining Activity of Wipes
If the scintillation counter
only provides results in
counts per minute (cpm) it
will be necessary to
convert those results to
disintegrations per minute
(dpm). This can be done
by including a control
sample with your wipes
that contains the isotope
of interest.
dpm = cpm / counting
efficiency
Standard (cpm) / Standard
(dpm) = Efficiency
1 uCi = 2.22 X 106 dpm
Decay of the standard’s
activity must be considered.
Lesson 10
Contamination Control
Contamination
• Definition:
• Undesired
locations:
• Types:
Radioactive material in an
undesired location
Surfaces, skin, internal, airborne
Removable – Decontamination is
possible
Fixed – Unable to decontaminate
Contamination Limits
•<20 dpm/100cm2 a in restricted areas
•<1,000 dpm/100cm2 b/g in restricted areas
(radioisotope laboratories)
•>1,000 dpm/100cm2 b/g immediately clean up to
below 1,000 dpm/100cm2
Frequently Contaminated Items
in Laboratories
• Radioactive containers (stock, flasks, beakers)
• Laboratory benches and sinks
• Laboratory apparatus and equipment
(Centrifuge, Freezer, Waterbath)
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Radioactive waste containers
Refrigerator door handles
Laboratory door handles
Gloves and laboratory coats
Contamination Control
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Work in areas designated for radioactive material
Use absorbent pads
Wear appropriate protective clothing
Change gloves frequently
Perform a dry run of the procedure without
radioactive materials
− It is recommend that you set up well-
defined, clearly labeled radioactive
material work stations and restrict
radioactive materials use to those areas
Spill Response
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Notify people working in the laboratory
Control access to the affected area
Wear gloves, lab coat, and safety glasses
Clean spill from the outer perimeter inward
Avoid spattering and generating aerosols
After initial clean up, monitor for contamination
Repeat process if contamination remains
Call the RSO (x2243) if you need help or if the
spill is greater than 100 µCi
Decontamination of Skin
• If the radioactive material is a high energy
beta, gamma, or x-ray emitter, monitor with a
survey meter and record reading
• Gently wash the affected area for 15 minutes
with lukewarm water and a mild soap
• If you continue to find contamination, repeat
washing and monitoring for up to 3 times
• Record final survey meter readings
• Contact Radiation Safety at x2243
Lesson 11
Obtaining Radioactive Materials
Ordering Radioactive Material
• Orders are placed electronically through Buy ND
• All orders must be approved by the Radiation Safety
Office
• When purchasing radioactive material from a vendor
provide the following:
– The Radioisotope
– Amount of material
– Name and phone number of P.I.
• All packages must be addressed to Central
Receiving/Douglas Road attn: Risk Management and
Safety
Receiving Radioactive Material
Ordering
− Typically, orders arrive the
following day
− Ensure that somebody is
available to pick up the
Package
− Wear lab coat and
dosimeter to pick up
package
− Sign receipt log prior to
leaving Safety
Check Contents
− Check box for contamination
using a Geiger counter or
wipe test.
− Confirm that content of
package is not contaminated.
− If it is contaminated contact
Safety.
− Deface or remove any
radiation labels on the box
and discard as regular waste.
Receiving Radioactive Material
− Checking package for contamination (Left)
− Defacing labels (Right)
Lesson 12
Radioactive Waste
Radioactive Waste Disposal
• Minimize generation of waste
• Identify and segregate dry solid waste
- long lived (H-3 and C-14)
- - short lived (P-32 and S-35)
•Complete a waste form for pickup
• Keep disposal records
Do Not Mix Waste Types
• Do not place scintillation vials into dry solid
waste containers
• Do not place dry solid waste into liquid
scintillation vial waste
• Do not place liquid waste container into dry
solid waste containers
• DO NOT MIX LONG AND SHORT HALF-LIVED
WASTE (Break point = 89 days)
Holding Radioactive Waste
for Decay
• Provide appropriate shielding for the waste
• Seal the container to prevent individuals from
adding to the waste
• Label the waste container with the isotope,
amount of radioactive material, and date the
container was sealed
• Hold for 10 half-lives. This will be done by RM&S.
Radioactive Waste Containers
• DO NOT dispose of
radioactive waste in:
- medical waste
containers
- general waste
containers
• Use only approved
radioactive waste
containers supplied by
Radiation Safety which
contains a warning
label “Caution
Radioactive Material”
Scintillation Vials
• Place in a separate container from the dry solid radioactive
waste
• Separate scintillation vials containing long lived isotopes
(H-3 and C-14) from those containing shorter lived isotopes
(P-32, I-125)
• Ensure the lids are secured tightly on the bottles
• Do not overfill the container
• Complete a Radioactive Waste Ticket and send to Safety
when container is full
Contaminated Sharps
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Syringes
Pasteur Pipettes
Scalpel
Needles
– Radioactive sharps must
be segregated from other
radioactive waste and
placed in a radioactive
materials labeled sharps
container.
Collecting Liquid
• Use a durable carboy from RM&S
• Attach a radiation warning label to the bottle
• Document the isotope, activity and date on the
container
• Secure the lid on the container at all times
Lesson 13
Clearing Equipment
Clearing Equipment
For repair by Engineering or Vendor:
• Ensure equipment is empty of all samples,
containers, and radioactive material
• Conduct wipe test and present results to RSO
• Monitor with survey meter
• Decontaminate equipment if required
Lesson 14
Review
When Working with Low Energy
Beta Emitters
• Examples: H-3, C-14, S-35, P-33
• Follow General Safety Requirements
• Use a GM survey meter for large quantities of
C-14, S-35 and P-33
• Isolate, label, and dispose of waste
• Secure material in refrigerator/freezer
When Working with High Energy
Beta Emitters (P-32)
• Use Plexiglas shielding for storage
• Wear Luxel dosimeter and extremity dosimeters
if required
• Handle material behind a Plexiglas shield
• Regularly monitor work area and gloves for
contamination
• Use a GM detector or liquid scintillation counter
Working with Gamma or X-ray
Emitters (I-125)
• Store in leaded containers
• Pre-experiment thyroid scan for work with large
quantities or volatile forms of I-125
• Wear Luxel dosimeter and extremity dosimeters if
required
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•
•
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Use leaded glass/Plexiglas shield
Regularly monitor surfaces gloves
Use NaI detector or liquid scintillation counter
Post experiment thyroid scan for work with large
quantities or volatile forms of I-125
Telephone Numbers
• Radiation Safety: 1-5037
• Fax: 1-8794
• Risk Management & Safety website:
•
www.riskmanagement.nd.edu
After hours, weekends, holidays: Call
ND Security 1-5555