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Radiation Safety Training
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OUTLINE

• RADIATION PHYSICAL FORMS BASIC DEFINITIONS
• RADIOISOTOPE DATA
• UNITS DEFINITIONS USED IN RADIATION
• RADIATION DOSIMETRY UNITS
• DOSE LIMITS
• PRECAUTIONS FOR AVOIDING UNNECESSARY RADIATION
  EXPOSURE
• RADIOACTIVE MATERIAL SPILLS
• BADGING OF PERSONNEL

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RADIATION PHYSICAL FORMS BASIC DEFINITIONS
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Structure of the Atom
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Elements and Isotopes
Periodic Table of Elements
Chart of the Nuclides
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Radioactivity
Definition Any spontaneous change in the state of
the nucleus accompanied by the release of energy.
Major Types
alpha (?) particle emission (decay) beta (?)
particle emission (?-), positron emission (?)
and orbital electron capture (ec) gamma (?)
decay including internal conversion
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Radioactivity

• Radioactivity and radioactive properties of
  nuclides are
• Determined by nuclear considerations only!
• Independent of the chemical and physical states
  of the radioisotope
• Cannot be changed by any means except for decay
• Unique to the respective radionuclide

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Ionizing Radiation
Definition - Any type of radiation possessing
enough energy to eject an electron from an atom,
thus producing an ion.
Major Types of Ionizing Radiation Alpha, Beta,
Gamma
Alpha Particle
Large Mass (nuclei) Helium Atom with a 2 charge
Beta Particle
Small Mass - Electron (subatomic particle)
No Mass (Electromagnetic Radiation)
Gamma Photon and X-Rays
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? Decay
? has a discrete energy that can be measured and
related to the parent. The neutron to proton
ratio is to low !
4He Nucleus Ejected from Nucleus
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Most of the energy associated with
? (monoenergetic)
This is radioactive!!
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? Decay
Either too many neutrons or too many protons
Change a neutron into a proton take away - charge
neutrino
(negatron)
anti-neutrino
Change a proton into a neutron take away charge
(positron)
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Electron Capture
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? Decay

• Emission of a photon from the nucleus
• Most often occurs after ? or ? emission when
  nucleus is left in an excited state
• Given off with discrete energies
• Can measure photon energy and possibly identify
  parent

or
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RADIOISOTOPE DATA
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Units Definitions Used in Radiation
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Activity
Definition The rate of decay of a radioactive
sample, i.e. by the number of atoms that decay
per unit time.
Units of Activity
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International Unit of Activity
Becquerel (Bq) 1.00 Bq 1 dps 60.00 Bq 1
dpm 1.00 Ci 3.7 x 1010 Bq
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Know the difference!!!!
radiation energy in the form of particles or
waves emitted from a radiation source
contamination radioactive material in an
undesirable location
Can radiation be contamination?Can
contamination be radiation?
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HALF-LIFE (T1/2)
The time required for a radioactive substance to
loose 50 percent of its activity by decay.
Each radionuclide has an unique half-life.
Half-life is expressed by the following Expression

A A0e-l(Dt)
Where Ao original activity l
.693/half-life of nuclide Dt difference
between reference date and present time
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Counts, Count Rate, Net Count Rate Background
Counts are the number of non-qualifiable
radioactive events seen by a detector Count
rate is the number of counts seen per unit time
as counts per second (cps) and counts per minute
(cpm). Net count rate is the number of counts
seen per unit time adjusted for the background
count rate Background is the ambient count rate
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Counting Efficiency
Counting efficiency is the calibration of count
rate in a specific detector where to quantify
and express the observed count rate in units of
radioactivity Cpm/dpm efficiency Each isotope
of interest has it own counting efficiency,
Liquid Efficiencies (LSC) H-3 (.35), C-14 (.85),
P-32(.98), P-33(.85) S-35(.85), I-125(.75),
I-131(.85) P-32 Cerenkov(.30)
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Liquids/Wastes Counting Calculations
Sample CPM Background CPM 2.22E6 DPM/uCi X EFF
X V(G)uCi/V(G)
Liquid Efficiencies (LSC) H-3 (.35), C-14 (.85),
P-32(.98), P-33(.85) S-35(.85), I-125(.75),
I-131(.85) P-32 Cerenkov(.30)
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Wipe Test Calculations
Results must be in DPM/100 cm2
DPM/ 100 cm2 Wipe CPM BKG CPM
(Eff)
For all Isotopes Eff 0.33
Therefore
DPM/ 100 cm2 (Wipe CPM BKG CPM) X 3
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Determination of Minimum Detectable Activity (MDA)

_________________ MDA in dpm 2.71 4.66 v bkg
cpm x count time
(eff) (count time)

______________ MDA in uCi/ml 2.71
4.66 v bkg cpm x count time
(2.22E6 DPM/uCi)(Sample Vol.)(eff) (count time)

MDA is the activity threshold for the counting
instrument for a given backgroundto decrease
this value, increase your counting timeot
increase your sample size. Results less than
this value are reported as ltMDA
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Radiation Dosimetry Units
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Radiation Dosimetry Units Exposure, X
amount of charge produced anywhere in air by the
complete stoppage of all electrons liberated by
photons in an incremental volume of air per unit
mass of air in that volume.
Standard International (SI) unit
Coulomb/kilogram (C/kg) Traditional unit
roentgen ( R ) 1 R 2.58x10-4 C/kg
Exposure definition applies only to photons of
energy less than or equal to 3 MeV interacting in
air.
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Radiation Dosimetry Units Absorbed dose
RAD
is the energy deposited by any type of ionizing
radiation in a volume element of mass.
SI unit gray (Gy)
Traditional unit rad 1Gy 100 rad
Absorbed dose definition applies to all forms of
ionizing radiation in any material.
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Relative Biological Effectiveness and Quality
Factor
Relative Biological Effectiveness (RBE)
Quality factor (Q) radiation Q photon,
? 1 proton, neutron 10 alpha 20
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Relative Biological Effectiveness
Ln (S)
Shoulder of curve indicates cell repair at low
doses
No shoulder - no cell repair
Neutrons
Effect
Gamma Photons
Dn
Dg
Same Biological Effect Different Dose from 2
types of radiation
Dose
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Radiation Dosimetry Units Dose Equivalent
Dose equivalent allows the description of the
biological effect of an absorbed dose of a
particular type of radiation or mixed radiations
for the Human Body.
Dose Equivalent (DE) in Rem Dose in Rads x Q
SI unit sievert (Sv) traditional unit rem
1 Sv 100 rem millirem
For photons 1 R ? 1 rad 1 rem
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DOSE LIMITS
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Occupational Dose Limits for Radiation Workers
Source of Radiation
Whole Body Dose is not to exceed 5 rem/ yr
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Occupational Exposure Limit to the Extremities
The Dose Limit to the Extremities may not exceed
50 rem / yr
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Occupational Dose to the Lens of the Eye
Dose must not exceed 15 rem/ yr
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Occupational Dose Limit for Declared Pregnant
Mothers and Occupational Minors
Dose must not exceed 0.5 rem or 500 mrem during
the gestation period for declared pregnant
mothers. Occupational minors must not exceed
this dose in a year long period
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Radiation Effects for EmbryoDeclaration of
Pregnancy for Occupational Mothers

• Rapidly dividing and non-specialized cells are
  more sensitive to radiation
• Birth defects have been observed
• Dose limit to embryo / fetus is 500 mrem for the
  gestation period

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Protecting the Embryo/Fetus

• The only way to protect the embryo/fetus from
  excess radiation is to protect the mother
• Belly badge for the baby is issued
• Bioassay for radioactive material intake is
  initiated and repeated monthly
• Dose to baby is measured/ estimated and reported
• Historically, pregnant women were not allowed to
  work with radiation
• Loss of position and Loss of pay
• To protect her baby, a mother must voluntarily,
  in writing, declare herself pregnant
• Present to Principal User/Supervisor and to the
  Radiation Control Office
• Additional information is available through the
  Radiation Control Office
• Confidential discussions with RSO about radiation
  risks to embryo/fetus
• Even if just planning to get pregnant
• Arrangements may be made to discuss with female
  radiation health professional

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Annual Dose Limit to a General Member of the
Population
X-ray room
Must not exceed 0.1 rem or 100 mrem
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PRECAUTIONS FOR AVOIDING UNNECESSARY RADIATION
EXPOSURE
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External Radiation Exposure
Definition Exposure of the body from radiation
originating outside of the body
Level of Hazard and Control Depend Upon
1. Type of Radiation (Alpha, Beta Gamma)
2. Energy of the Radiation (Low or high energy)
3. Dose Rate (Low or high dose rate)
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Reducing External Radiation Exposure

• Time
• reduce time spent in radiation area

• Distance
• stay as far away from the radiation source as
  possible

• Shielding
• interpose appropriate materials between the
  source and the body

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Reduction of Exposure Time

• Training
• should include a full rehearsal of the procedures
  outside of the radiation area to improve
  efficiency and confidence

Power and automated equipment Lab design allows
easy access to the equipment and
components Practice your procedures 5 times with
colored water. This will allow you to work
faster, will save your lab money, and reduce the
chance of having an accident.
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Distance from the Source
Okay if the distance between the source and point
of interest is at least five (5) times the
greatest dimension of the source.
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Control of Distance
remote operation manipulating devices, remote
handling tools

• moving away from sources
• remain near a source only when it is necessary
• Leave the radiation work area if you are not
  needed for the procedure

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• Shielding
• Basic principle
• Place materials between the source and person to
  absorb some or all of the radiation
• a radiation no shield required for external
  exposures dead skin layer stops ?s
• b radiation ranges of meters in air some can
  penetrate dead skin layer thin Plexiglas shields
  adequate
• x and ? radiation highly penetrating, best
  shields are high atomic number materials (lead)

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RADIOACTIVE MATERIAL SPILLS
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Radioactive Material Spills All Disposable Spill
Kit in Immediate Location Required Materials
Absorbents- Powder and/or Pads -Neutralizing
Material
Barriers - CAUTION Tape / Rope / Signs
PPE - Gloves / Lab coat / Apron / Booties / Eye
wear / Respiratory protection if trained and fit
tested
Clean-Up Supplies - Small brush and dustpan /
Detergent solution / Scrub pad / Paper towels
Waste Containers - Clear plastic Bags - assorted
sizes / Material to seal bags
Wipe Test Supplies - Filter paper to fit your
system / Containers for filters / Envelopes /
Planchets or vials / Wipe test forms / Marker for
containers / Sharpie / Grease Pencil / Tape
Survey Equipment On Hand - Appropriate to
Isotopes used
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RADIOACTIVE MATERIAL SPILLS

• Materials
• Determine Spill Confinement
• Determine Exposure Rate
• Apply Absorbent (if necessary)
• Restrict Access to Spill Area
• Don PPE
• Mark Area of Spill
• Clean Up Spill
• Wipe Test
• Manage Clean Up Waste
• Personal Exit Survey
• Evaluate the Wipe Test
• Reporting

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BADGING OF PERSONNEL
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UGA Dosimetry Policy

• All rad workers are provided dosimetry for 6
  months
• RCO provides 1 permanent badge per authorized
• Principal Investigator free of charge.
• After 6 months, rad workers badges receiving
  less than
• 100 mRem are terminated unless Principal
  Investigator
• decides to keep those rad workers badged and
  covers
• the cost of dosimetry.
• Most X-ray workers are permanently badged by
  regulation

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External Radiation Dosimetry

• Primary UGA dosimeter is the TLD Badge
• Sensitive to gamma and hard beta radiations
• Provides UGAs RSO dose information on a monthly
  or quarterly basis

Responsibility Your Responsibility to exchange
your badge !!
Badge Exchange -Not contaminated -Change out
procedure with departmental badge
coordinator

• Does not provide information during a real time
  exposure to radiation

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Body Badge Location
Badge
Source
Between Neck and Waist Closest to Source of
Radiation
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Ring Badge Location
Your Ring Badge will come with your name on it.
Wear the badge with the name plate facing the
source of radiation.
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Exchanging your Dosimetry Badge
WHERE? Usually at your departments main
office or designated laboratory WHO? A
designated person who handles all the badges for
your department, typically someone in your
departments main office. WHEN? Quarterly badges
are exchanged at the end of every calendar
quarter March 31, June 30, September 30 and
December 31
Monthly badges are exchanged at the end of every
month !
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Questions ???
If you have any questions while reading the
Radiation Safety Procedures
Please Feel Free to Contact The Radiation
Safety Office
Environmental Safety Division University of
Georgia 240A Riverbend Road Athens, Georgia
30602-8002
542-5801