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Division of Medical Physics and Radiation Safety
617 638 7052
Radiation Safety Awareness
for
This training does not substitute for Basic Radiation Safety Training.
You will
Chemistry Students
Disclosure
This training does not substitute for Basic Radiation Safety Training offered to BU Radioisotope
Authorized Users.
You are only authorized to use radioactive material for during this class-XX.XX.
Massachusetts Department of Public Health Radiation Control Program (RCP) issued Radioisotope License to:
Boston University and Boston Medical Center
(BU) and (BMC) Medical + Research Patient Use X-ray, Therapy Units, and Lasers
Radioactive Materials Licensure
4 RPO
BROAD SCOPE MATERIALS LICENSE
BUBU
RSC
Permit Holder
User
DMPRS
Radiation Supervisor/Lab Coordinator
Radiation Use at BU and BMC
Radiation is used at BU and BMC as:
Radioactive Materials Radiation Generating
Devices Irradiators
Radiation Protection Office\Dept\12 Training Program Management\Maintenance Training
Radiation Uses at BU and BMC
Examples: Research with radioisotope tracers to study
diabetes, infection, cancer and DNA Medical Use Irradiating patient’s blood to prevent transfusion
reactions Heart Scans Treating Prostate Cancer Diagnostic X-rays (Dental, Chest, CT, etc.)
7 RPO
ALARA An acronym for "As Low As Reasonably Achievable." It
means making every reasonable effort to maintain exposures to ionizing radiation as far below the dose limits as practical.
The goal of radiation protection is to keep radiation doses As Low As Reasonably Achievable
BU is committed to keeping radiation exposures to all personnel ALARA
The National Council on Radiation Protection and Measurements (NCRP) published a study of the U.S. population’s exposure to radiation in 2009. The chart below shows sources that contributed to an annual average dose of 620 millirem per year. This is a national average, individual exposures will vary.
Sources of Radiation Exposure NCRP Report No. 160 (2009)
9 RPO
Do you workdirectly with a
source of radiation?
NoBadge
Required
Is the radiationsource an
isotope or a machine?
No
Yes
Do you work with at least one of the followingisotopes (greater than activity indicated)?(badge type in ( ).
Brachytherapy Sources (1,4) >1 mCi/qtr. of gamma or positron emitter (1,4) >1 mCi high (>500 keV) max energy Beta emitter (1,4) Nuclear Radiology Isotopes (1,4)
Do you work with any one of the following machines?(badge type in ( )
Fluoroscope (2,3) LINAC (1) Diagnostic x-ray (2,3) CT (2,3)
Isotope Machine
A badge is mandatory
A badge is voluntary
Yes
NoBadge Type1 – Whole body2 – Collar3 – Waist4 - Ring
Dosimetry Requirement Decision Tree
No
Basic Terms
Radiation: energy in transit in the form of high speed particles and electromagnetic waves.
Radioactivity: Characteristic of an unstable atom that releases energy in the form of a particle or electromagnetic wave.
12
Types of Ionizing Radiation
Alpha particles: contains 2 neutrons and 2 protons, which is ejected from the nucleus of a radioactive atom.
Beta particles: A high-speed electron or positron, usually emitted by an atomic nucleus undergoing radioactive decay. Electrons carry a negative charge.
X-rays: Electromagnetic radiation originating in the electron field of an atom.
Gamma rays: A gamma ray is an electromagnetic radiation originating in the nucleus of an atom.
13
Types of Radiation
Ionizing Radiation: Radiation capable of liberating electrons from an atom. ex. beta particles, x-rays
Non-ionizing radiation: Radiation not capable of liberating electrons, but can excite the atom.
ex. microwaves, radio waves, lasers
14
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Terms and Definitions
Radiation: Energy in transit in the form of high speed particles and electromagnetic waves.
Radioactivity: Characteristic of an unstable atom that releases energy in the form of a particle or electromagnetic wave.
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Units
There are two systems of units used in the measurement of radioactivity and radiation dose.
The older units (Curie,Rad and Rem) - the American System and U.S. regulatory units.
The widely-used international units (Becquerel, Gray and Sievert) – International System or “SI” system.
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Radiation Quantities
Curie: 3.7x1010 disintegrations per second or 2.2x1012 disintegrations per minute.
1 curie (Ci) = 2.2 x 1012 dpm 1 millicurie (mCi) = 2.2 x 109 dpm 1 microcurie (µCi ) = 2.2 x 106 dpm
Example: 100 µCi = 0.1 mCi = 2.2 x 108 dpm
Becquerel: One disintegration per second. (SI system) 1 mCi = 37 Megabecquerels (MBq) 1 µCi = 37 kilobecquerel (kBq)
Example: 0.1 mCi = 3.7 MBq = 100 µCi
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Radiation Units
Roentgen: unit for measuring the amount of ionization in air (exposure) due to gamma or x-rays.
RAD: Radiation Absorbed Dose.Unit used to describe the amount of energy absorbed from radiation in any type of medium.
100 rads = 1 Gray (SI)
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Radiation Units
REM: Unit used for measuring human dose equivalent. 100 rem = 1 Sievert (SI) 1 rad of alpha = 20 rem 1 rad of beta = 1 rem
Note: Two different types of radiation may deliver the same absorbed dose, but produce a different biological affect, and hence, dose equivalent.
1 rad of alpha = 20 rem 1 rad of beta = 1 rem
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Half-Life
The time required for any given radioisotope to decrease to one-half of its original activity by radioactive decay.
This period of time is called the half-life.P32 - 14.3 days
C14 - 5730 years
H3 - 12.3 years
S35 - 89.7 day
I125 - 60 days
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External Exposure
Common isotopes with external exposure potential
ex: P-32, I-125, Cr-51
Not all radioisotopes are external exposure hazards
ex: H-3, C-14, S-35
External Radiation
Three ways to reduce exposure from external radiation sources
Time
Distance
Shielding
30 min work time in a 40 mR/hr field= ???
.5 hr x 40 mR/hr = 20 mR
Time and exposure have a linear relationship. As time decreases, the exposure decreases proportional to time.
50 cm 100 cm 200 cmDistance from
source:
Dose rate: 40 mR/hr 10 mR/hr 2.5 mR/hr
Distance and exposure have an inversely proportional relationship. As distance increases, photon exposure decreases at the rate of the inverse of distance squared.
99mTc dose in shielded Pb carrying case
The type of shielding that is suitable for one type of radiation may not be suitable in shielding another. Always consult the Radiation Safety Office to ensure that your shielding is appropriate.
26 RPO
How To Minimize External Exposure
DISTANCE : Inverse Square Law 10 mR/hr @ 1 ft At 2 ft. - What is your exposure?
10 mR/hr = 2.5 mR/hr 2 ft.2
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Shielding
Alpha particles can be stopped by a sheet of paper.
Most Beta particles can be stopped by 1-2 cm of Plexiglas.
Most gamma and x-ray photons can be absorbed by several cm of lead.
Neutrons may require several feet of concrete.
CAUTION
Radiation Label
Refers to areas accessible to personnel, in which a major portion of the body could receive a dose of 5 mrem in anyone hour at 30 centimeters from the radiation source or from any surface that the radiation penetrates.
RADIATION AREA
Do NOT enter unless authorized
32
Contamination
Definition: Radioactive material where it shouldn’t be.
e.g. floors, bench tops, hands
All radioisotopes have contamination potential even if they do not have external exposure potential.
The goal is to prevent contamination from getting on to your skin and/or inside your body.
33 RPO
Skin Contamination
Cool water, mild soap
2-3 minutes working up a good lather, dry
No harsh chemicals or detergents
Survey for contamination
Notify the RPO 617-638-7052
34 RPO
SPILLS
S Stop all work and contain spill W Warn others I Isolate Area M Minimize exposure and monitor N Notify RSO
35 RPO
Proper Survey Technique
Use appropriate survey meter Check battery Audible on Check background level
Audio On/Off Switch
Rotary Switch Off Battery Check Scalar Multiplier
Battery Compartment
RPO
Surveys
Geiger Counters used for all isotopes (EXCEPT H-3)
Note: Contamination Surveys use for I-125 use Gamma Scintillator Gamma Scintillator (NaINaI) probe.
End Window PancakePortable
Survey Meter
Gamma Scintillator (NaI) probe
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Survey Meter Face Plate
Top scale : 0 - 4.2 Kcpm on X 1X 1 multiplier
Bottom scale: 0 – 200 mR/hr on X 100X 100 multiplier only
Middle scale: 0 – 2.0 mR/hr on X 1X 1 multiplier
38 RPO
Wipe Tests A wipe test only assesses removable contamination. A dry material to wipe an (100 cm2) area of potential
radioactive contamination. For H-3, a wipe test is the only means to assess
potential contamination. For P-32, S-35, C-14, use Geiger Mueller Probe for
fixed and removable contamination surveys
Liquid Scintillation
Counter
39 RPO
Container Labeling
You must ensure that all containers possessing radioactive material are labeled with: Radioisotope Quantity Date Chemical Name
40 RPO
Sulfur 35- Amino Acid Precautions
Because of volatility: Use fresh stocks Open Stock vial in hood Place charcoal in incubators, water baths,
etc. Monitor with GM (pancake) especially
centrifuges, incubators, bag sealers
Working with Eppendorf tubesWorking with Eppendorf tubes
RPO 41
Use flat top tube opener to reduce radiation levels to fingers
42 RPO
Radioactive Waste Categories
Solid waste Aqueous liquid waste Organic liquid Deregulated liquid scintillation vials Regulated liquid scintillation vials Animal carcass/tissue Volatile material Stock vials
43 RPO
Rad. Waste Guidelines
Put radioactive needles etc., in “radioactive” sharp container
No liquids No lead pig or radiation labels in rad.
waste (deface all radiation labels) Assure rad. waste container labeled to
prevent housekeeper from emptying trash
Call DMPRS for any questions at
617-638-7052
44 RPO
Radiation Safety Records
All records must filled out and up to date!
Inventory Surveys Waste logs Sink logs
45 RPO
Radiation Safety Checklist
All persons completed required training? Are radioactive materials secured? Do you use a survey meter and/or wipes to
assess exposure and/or contamination? No eating, drinking or application of
cosmetics in the laboratory? Report spills to Radiation Safety 617 638
7052?
Security
Security involving research material
All radioactive material must be secure from unauthorized removal or access.
The Authorized User of radioactive material must maintain constant surveillance, and use devices or administrative procedures to prevent use by unauthorized personnel.
47 RPO
Security of Radioactive Material
You can do one or more of the following: Keep radioactive material in constant view Lock up radioactive stock solutions Lock the laboratory Always keep the access door to your floor of
the building locked. ( Use Key Card Access or the Combination Lock )
Risk of exposure to ionizing radiation Minimal Exposure = Minimal Risk
If 100,000 persons were exposed to 10 Rem of radiation each, 800 excess cancer deaths would be expected during their remaining lifetimes in addition to the nearly 20,000 cancer deaths that would occur in the absence of radiation.-BEIR V Report, page 162 - 1989
Latest Biological Effects Studies