Radioactive Contamination and Procedures of Decontamination

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Radioactive Contamination and Procedures of
Decontamination
Training Course on Radiation Protection for Radiation Workers and
RCOs of BAEC, Medical Facilities and Industries, TI, AERE, BAEC
Savar, 27 October 2021
Dr. MD. IDRIS ALI
CSO, HPRWMU
INST, AERE, Savar

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Contents
• Radiation Basics
• Radioactive Contamination Basics
• Types, Units and Detection of Contamination
• Personal & Workplace Contamination Control
• Decontamination Basics
• Decontamination Procedures

Radiation Basics: Radiation & its Origin-1
Radiation is energy traveling in the form of electromagnetic wave (EM) wave or
particle which may be nuclear or non-nuclear in nature. Example: Light, x-ray,
alpha ray, beta ray, gamma ray etc.
Nuclear Radiation is the radiation that is emitted from the nucleus of an atom.
Example: Alpha, beta, neutron & gamma ray.
Non-Nuclear Radiation is the radiation that is emitted from other than nucleus
such as vibration of atoms, excitation of electrons. Example: X-ray, light etc.
Non-Nuclear Radiation Nuclear Radiation
Origin: Nucleus of the atom
Origin:
• Vibration of atoms
• Excitation of electrons
Energy Spectrum

Radiation Basics: Atom and Molecule -2
Molecule
Atom
An atom is smallest particle in an
element that has the properties of
the element.
Molecules are formed by the combination of
two or more atoms. The atoms are bonded
together in a molecule.
Carbon Atom
Proton
Z
Neutron
N
Electron
+
_
6+6C= 12C

Radiation Basics: Nuclear Radiation & Radioactivity-3
Radioactivity: Unstable atomic nuclei spontaneously decay to form
stable nuclei. The decomposition process is called radioactivity and
was discovered by Henri Bequerel in 1896. The energy and/or
particles which are released during the decomposition process are
called Nuclear Radiation.
Stable unstable
Hydrogen Carbon Uranium
238U has 92 proton
and 146 neutrons
12C has 6 proton and
6 neutrons

• Radioactive material/Radionuclide/Radioisotope are
synonymous
Radiation Basics: Nuclear Radiation & Radioactivity- 5
Radiation: Types
1. Particle Type: Alpha, beta, neutron etc.
Wave Type: X-ray, gamma etc.
2. Charged Type: Alpha, beta etc.
Uncharged Type: Gamma, neutron etc.
3. Ionizing Type: Alpha,
beta, gamma, neutron, X-
ray etc.
Non-ionizing: Light,
microwave, UV ray etc.

Radiation Basics: Types of Radioactive Materials- 7
Solid Gaseous
Liquid
Co-60, U-235, Ra-
226, Pu-239, Th-
232, K-40, Cs-137,
etc.
I-131, P-32 for
radiotherapy,
reactor core etc.
Ar-41, Kr-85, Rn-
222, Xe-133, C-14,
I-131 etc.
Unsealed Sources
Sealed Sources
I-131, P-32, H-3, Tc-
99m for etc.
Co-60, Cs-137, Cf-
252, etc.
Radiotherapy
Head
Reactor core

Radiation Basics: Radioactivity and Half-life- 8
Isotope: Same Proton number (Z) and
different Neutron number (N) and thus
different Mass number A. Exam. 12C is a stable
isotope of Carbon.
Radioisotope: Element with unstable nucleus
undergoing spontaneous decay to end up with
an stable decay product. Exam: 14C is a
radioisotope of Carbon with a half-life of 5730
years.
Radioactivity and Half Life
The rate of decay of a nuclear substance is defined
by its activity. The unit is: Curie (Ci) or Becquerel
(Bq).
1 Bq = 1 disintegration per second (dps)
1Ci = 3.7 x 1010 Bq or dps
Half-life: The amount of time required for an
initial activity to be reduced by ½ or 50%.
Elements Half-life Radiation
Tc-99m 6 h , 
Iodine-131 8 d , 
Co-60 5.27 y , 
Cs-137 30.17 y , 
Am-241 433 y 
Ra-226 1600 y 

Uses of Radioactive Materials
Applications Use Radioisotope
Power Plant Generation electricity 235U, 239Pu etc.
Nuclear Medicine Diagnostic and Therapeutic
processes
Gamma/beta emitters:
131I, 125I, 99mTc, 137Cs, 60Co
Research and
Education
Research on materials, food
irradiation, plant breeding etc.
Gamma and neutron
emitters
Manufacturing Thickness of coatings, weight,
moisture content etc.
Gamma emitters: Co-60,
Cs-134 Cs-137, Sr-90,
Am-241 etc.
Chemical
Processing Density, Sp. Gravity, Pipe
thickness, Corrosion, Wear
Gamma; neutron sources
Am-Be, Pu/Be, Cf-252 etc.
Oil & Gas
Exploration Column scanning, level
measurement etc.
Gamma; neutron sources
Agriculture &
construction
Soil moisture measurements,
location of reinforcing bar etc.
neutron sources
Nondestructive
Test
Weld, valves, parts, pressure
vessels, aircraft structures etc. Co-60, Cs-137, Ir-192 etc.
Radiation Basics: Uses of Radioactive Materials- 9

Module Medical VIII. 25
Radiation
Cytotoxic
Cell death
Tissue injuries /
Scar formation
Metabolic / functional
disturbance
Repair
Transformation
（Low dose）
（High Dose）
cell cycle arrest
Mechanism of Biological Effect
Radiation Basics: Biological Effect- 10

Radiation Basics: Biological Effects- 11
Direct Effect: Interaction with and breaking of DNA, damage of Cellular
structure.
Indirect Effect: Radiation ionizes molecules including water to form toxic
chemical ultimately affecting the DNA.
H2O +  = HOH+ + e- ; H2O + e- = HOH-
HOH+ = H+ + OH* ; HOH- = H* + OH-
Radiation from radioactive
materials enters human cell,
strike the nucleus and damage the
DNA causing uncontrolled
growth of cancer cell
OH* + OH* = H2O2

Specific Effect
General Effect
Radiation Effects
Somatic
Effect
Genetic
Effect
Stochastic
Effect
Deterministic
Effect
Early
somatic
effect
Late
somatic
effect
Acute dose,
shows up in
hours to weeks,
Death, cancer
Chronic dose,
shows up in
years, cancer
Gene
mutation,
Genetically
abnormal
offspring
Has threshold,
Collective damage
of organ,
Cataract, skin burn
etc.
Statistical in
nature, no
threshold, varies
with dose level,
Bone, lung
cancer, genetic
effect etc.
Radiation Basics: Types of Radiation Effects- 12
Self Offspring

Quantity Old Unit Symbol SI Unit Symbol Relationship
Activity Curie Ci Becquerel Bq 3.7 x 1010 Bq = 1 Ci
Absorbed dose RAD RAD Gray Gy 1 Gy = 100 RAD
Equivalent dose REM REM Sievert Sv 1 Sv = 100 REM
Effective dose REM REM Sievert Sv 1 Sv = 100 REM
Dose: A measure of the energy
deposited by radiation in a
target object (any material).
Exposure: The act or condition
of being subject to irradiation.
Exposure can either be external
or internal. Unit is Roengent (R).
Radiation Basics: Exposure, Dose and Units- 13

Radiation Basics: Radiation Weighting Factor (WR) & Tissue
Weighting Factor (WT)- 14
Radiation Type WR
X & Gamma Rays 1
Beta Rays 1
Thermal Neutrons 5
Fast Neutrons 20
Alpha Particles 20
High Energy Protons 2
Tissue weighting factors-ICRP 103 (ICRP 2007)
Tissue Tissue weighting
factor- WT
ΣWT
Bone-marrow (red),
colon, lung, stomach,
breast, remaining
tissues(*)
0.12 0.72
Gonads 0.08 0.08
Bladder, oesophagus,
liver, thyroid
0.04 0.16
Bone surface, brain,
salivary glands, skin
0.01 0.04
Total 1.00
(*) Remaining tissues: Adrenals, extrathoracic region, gall
bladder, heart, kidneys, lymphatic nodes, muscle, oral
mucosa, pancreas, prostate (♂), small intestine, spleen,
thymus, uterus/cervix (♀).
WR for Neutrons ranges from
~2-20 depending energy

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Radiation Basics: Effects of Whole Body Dose- 15
Acute Dose Effect (Whole Body) Dose
Lowest dose for any statistical risk of cancer 50 mSv
Mild radiation sickness (headache, infection) 0.5-1 Sv
Light radiation poisoning (mild to moderate nausea,
fatigue, 10% risk of death after 30d
1-2 Sv
Severe radiation poisoning (Vomiting, hair loss, 35%
risk of death after 30d
2-3 Sv
Severe radiation poisoning (bleeding in mouth, under
skin, 50% risk of death aft 30d (Lethal Dose)
3-4 Sv
Acute radiation poisoning (bone marrow destroyed,
nearly 100% death after 14 days
6-10 Sv
Acute radiation poisoning (massive diarrhea,
internal bleeding, coma)
10-50 Sv
Coma in secs. or minutes, death within hours 50-80 Sv
Instant death >80 Sv

ALARA
(As
Low
As
Reasonably
Achievable
Justification Optimization
Dose limitation
Risk < Benefit
Parameters Workers
(mSv/y)
Public
(mSv/y)
Effect Dose 20 1
Equivalent Dose
Lens of eye
Skin
Extremities
150
500
500
15
50
50
Radiation Basics: Radiation Protection Principles-16
Principles of Radiation Protection
Radiation Protection Technique
• Time
• Distance
• Source Barrier
• Personal Barrier
• Source Reduction
• Effect Mitigation
• Optimal Technology
• Limitation of Other Exposures
Shielding
Additional…

Radiation Basics: Radiation Protection Principles-17
Radiation Shielding Materials

•Radioactive Material
o Any substance that
spontaneously gives off
radiation
o Can be in various chemical
forms
o If not contained (sealed source)
can lead to contamination -
External, Internal or Both
•Radiation
– The energetic emissions of
radioactive material
– Can be subatomic particles (,
, n), photons (X-ray, ) or
combinations
– Results in ionization of the
absorbing material (if living
tissue  radiation injury)
Radioactive Contamination Basics- 1
Radiation vs Radioactive Material

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Radioactive Contamination is defined as the presence of radioactivity in
an unwanted area. Contamination occurs when radioactive material
(liquid, powder, etc.) is deposited on or in an object or a person or in a
place. Radioactive materials released into the environment can cause air,
water, soil, buildings, people to become contaminated.
Radiation Exposure is irradiation of the body resulting in an absorbed
dose. When a person is exposed to radiation, the energy penetrates the
body. This is called radiation exposure. For example, when a person has
an x-ray, he/she is exposed to radiation.
Radiation Radioactive materials give off a form of energy that travels in
waves or particles is called radiation.
Radiation Contamination

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How Contamination Differs From Exposure
A person exposed to radiation is not contaminated with radioactive material. A
person who is exposed to radiation has had radioactive waves or particles
penetrate the body. For a person to be contaminated, radioactive material must
be on or inside of his/her body. An uncontaminated person can be exposed by
being too close to radioactive material or a contaminated person, place, or thing.
Exposure Contamination
, ,
, n



n

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Exposure vs. Contamination

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Sources of Contamination
• A nuclear power plant accident
• An atomic bomb explosion
• An accidental release from a medical/industrial device
• Nuclear weapons testing
• Terrorism with RDD
• Practices using the radioactive sources
• Transportation
• Unwanted use of orphan sealed sources
The Dangers from Contamination
 External radiation exposure to the personnel
 Internal absorption if comes into contact with skin or is
inhaled or ingested contaminated food
 Interference with experiments being conducted in the lab

Contamination Basics: Sources- 6
NPP operation Contaminated food
Radioactive materials in Labs.

Reactor Accident Weapon Test Transport Accident with
RMs
Dispersal of Orphan
Sealed Sources
Spillages/leaks of
Radioactive Materials
Contamination Basics: Incidents Inducing Con.- 7

Contamination Basics: Ultimate Effect of Contamination- 8

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Personal or Individual
Contamination
• External Contamination
• Internal Contamination
Internal Contamination
• Inhalation
• Ingestion
• Absorption
• Injection
• Transplacental
• Fixed Contamination
•Removable or loose
Contamination
Area or Equipment
Contamination
Types of Contamination
Water, Airborne radioactivity & Cont. food
radioactive material in any chemical or physical
form that is present in ambient water, air and
food above natural background.
Radioactive Contamination Basics: Types- 9
Contamination of
Environment Soil, water & air

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External Contamination occurs when radioactive
material, in the form of dust, powder or liquid comes
into contact with a person's skin, hair or clothing. In
other words, the contact is external to a person's
body.
Instructions: Start at the head, continue
systematically over the whole body,
including the feet and soles. Repeat on
other side of the body. Full survey can
take several minutes.
How to diagnose-
• Scan with appropriate radiation survey meter.
Personal Contamination

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Internal Contamination results when radioactive material is taken into the
body via inhalation (breathing) or ingestion (food/water) or open wounds.
Some types are eliminated from the body by natural processes (sweat, urine
etc.). Other types of radioactive materials stay in the body depositing in
different body organs and may be removed by medical countermeasures.
Internal contamination continues until the radioactive material decays and
deposition of radioisotopes in organs results in local exposure at that location.
How to diagnose-
• If after external decontamination, an appropriate
radiation survey meter continues to identify
significant residual radioactivity, suspect internal
contamination.
• Swab each nostril separately to help estimate
level of internal (lung) contamination
• Collect ≥70 mL spot urine sample for isotope
measurement
Incorporation- after inhalation, ingestion, or wound contamination, small radioisotope
particles may be transported via blood or lymphatics into cells, tissues, and organs
(thyroid, lungs, kidneys, bones/bone marrow, or liver ).

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Fixed contamination refers to radioactivity remaining on
a surface after repeated decontamination attempts fail to
significantly reduce the contamination level.
Removable contamination or Spill refers to radioactivity
that can be removed from a surface by an absorbent
material, such as filter paper or cotton swabs by rubbing
with moderate pressure and swapping an area (at least
100 cm2).
Workplace/Equipment Contamination
Environmental Contamination- radioactive material in any
chemical or physical form that is present in ambient water,
air and food above natural background may contaminate
the natural environment
Environmental Contamination

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Contamination, High Contamination and Airborne Radioactivity Area
For the purpose of radioactive contamination control, three (3) different postings
are utilized.
CONTAMINATION AREA
If removable radioactive contamination exceeds:
• 1,000 dpm/100 cm2 beta-gamma contamination or
• 20 dpm/100 cm2 alpha emitting contamination
HIGH CONTAMINATION AREA
If removable contamination exceeds 100 times the
Contamination Area levels:
• 100,000 dpm/100 cm2 beta-gamma contamination or
• 2,000 dpm/100 cm2 alpha emitting contamination
AIRBORNE RADIOACTIVITY AREA
If airborne radioactivity concentration exceeds:
• Individual may be exposed to 12 DAC-Hours in a week or
• Individual may be exposed to 100% of a DAC at any time
Contamination is generally reported as the amount of activity measured over a
known surface area. The unit of contamination is: dpm/100cm2, dps/cm2 or
Bq/cm2
Radioactive Contamination Basics: Units & Limits- 11

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Contamination Activity Limit
To determine contamination, compare the background counts/minute to the
counts/minute of the wipe or survey meter. If the ratio of counts/ minute
exceeds 3:1 the area is contamination and should be decontaminated and
resurveyed until the ratio is less than 3:1. For example, if for background is 25
cpm, decontamination needs the area if the survey exceeds 75 cpm.
Detection of Contamination- 1
Beta/gamma monitor
Contamination detection
Alpha monitor Hand-foot Monitor

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Detection of Contamination- 2
Internal Contamination Detection
Whole Body Counter Thyroid uptake system

Limiting, Controlling and Preventing of
Contamination:
Workers/Labs./Facilities

Eleven Golden Rules to Handle Unsealed Radioactive Materials
1. Understand the nature of the hazard and get practical training.
2. Plan ahead to minimise time spent handling radioactivity.
3. Distance yourself appropriately from sources of radiation and use
appropriate shielding for the radiation
4. Always get detailed instruction and advice from experienced radiation
workers before starting work- do initial work under direct supervision.
5. Contain radioactive materials in defined work areas.
6. Wear appropriate protective clothing and dosimeters.
7. Monitor the work area frequently for contamination control.
8. Follow the local rules and safe ways of working.
9. Minimise accumulation of waste and dispose of it by appropriate routes.
10. After completion of work monitor yourself, wash and monitor again .
11. Always discuss work procedures and get detailed advice from experienced
radiation workers.
Personal Contamination Control- 1

• Source sign out/in logs
• Physical inventories
• Leak Tests
− Alpha sources every 3 months
− Others every 6 months
• Lost, stolen, or damaged sources must be
reported to RCO
Rules for Safe Handling of Sealed
Radioactive Sources (SRS)

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How Radioactive Contamination Is Spread
People who are externally contaminated can contaminate other people or
surfaces. For example, people who have radioactive dust on their clothing
may spread the radioactive dust when they sit in chairs or come in contact
with other people.
People who are internally contaminated can expose people near them from
the radioactive material inside their bodies. The body fluids (blood, sweat,
urine) of an internally contaminated person can contain radioactive
materials. Coming in contact with these body fluids can result in
contamination and/or exposure.
How Your Home Could Become Contaminated
People who are externally contaminated can spread the contamination by
touching surfaces, sitting on a chair or even walking through a house.
External contaminants from clothing thus can contaminate house. Homes can
also become contaminated from internally contaminated people from body
fluids. Making sure that others do not come in contact with body fluids from
a contaminated person will help prevent contamination of other people.

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Limiting Contamination
Since radiation cannot be seen, smelled, felt, or tasted, people at the site of an
incident will not know whether radioactive materials were involved.
Following steps can be taken to limit contamination:
- Get out of the contaminated area quickly. Go inside the nearest safe
building or to health officials.
- Remove the outer layer of your clothing. If radioactive material is on your
clothes, getting it away from you will reduce the external contamination
and decrease the risk of internal contamination. It will also reduce the
length of time that you are exposed to radiation.
- If possible, place the clothing in a plastic bag or leave it in the corner of a
room. Keep people away from it to reduce their exposure to radiation.
Keep cuts and abrasions covered when handling contaminated items to
avoid getting radioactive.

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Limiting Contamination…
- Wash all of the exposed parts of your body using lots of soap
and lukewarm water to remove contamination.
- Try to avoid spreading contamination to parts of the body that
may not be contaminated, such as areas that were clothed.
- After authorities determine that internal contamination may
have occurred, treatment and decontamination process
should follow immediately.

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Contamination Control Methods
The most important aspect of preventing the spread of contamination is to
control it at the source which will reduce internal exposure and personnel
contamination. Two contamination control methods are in practice:
Preventative Methods
• Frequent inspection of liquid systems for leaks or potential problems
• Establish adequate controls prior to start working (radiological briefing)
• Change protective clothing frequently (gloves in particular) as necessary to
prevent the cross-contamination of equipment
• Place protective wrapping around non-contaminated items
• Practice good house-keeping and post-job clean-up
• Never eat/drink anything in a place containing radioactive materials
• Minimize the amount of material taken into a contamination area
• Follow approved procedures when working in contamination areas/with
contaminated material

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Engineered Control Methods
• Careful consideration is given when selecting materials
used in various systems subject to activation
• Work-site ventilation is used at times to maintain air-flow
from areas of least contamination to areas of higher
contamination
• High efficiency particulate (HEPA) filters are often used to
remove radioactive particles from the air
• Containment (gloves, bags, drapes, fume hoods, etc.) of
contamination as close to the source as possible

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Protective Clothing
Protective clothing is required when entering contaminated areas. This will help
prevent the cross-contamination of personnel skin and clothing. The degree of
protective clothing required is dependent on the work area radiological
conditions and the nature of the job.
Protective clothing generally consists of the following:
• Coveralls (cloth or paper)
• Cotton glove liners
• Gloves (rubber or surgical) – two sets required for full dress-out
• Plastic shoe covers
• Rubber overshoes
• Respiratory protection kit (full and half mask)
• Hood (full-face or surgeons cap) etc.
Personal Protective Gears (PPGs) or Clothing
With the administrative and engineering controls for radioactive contamination,
protective gears (PGs) or equipment should be used in parallel.

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Donning (wearing) protective clothing Before wearing, one should give a minimum
look for the following: • Inspect the coveralls for tears • Inspect all gloves for holes •
Make sure that the shoe covers and overshoes fit correctly
Gloves Shoe
covers
Respiratory
mask
TLD
Personal Contamination Control-10

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Monitoring of External Personal Contamination
Personal monitoring is required when exiting from contamination areas and
airborne radioactivity areas. A whole body frisk/check will normally be
required when exiting from contamination areas.
• The monitor (frisker) must have audible
(alarm) and visible response
•The frisker should be set up in areas
where the background count rate is less
than 100 counts per minute (cpm)
• The instrument shall be set to alarm at
100 cpm above the background count rate
Example: [CPM] divided by [efficiency] equals
DPM Example: 100 CPM at 20% efficiency =
100/0.2 = 500 DPM

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Internal Radiation Monitoring
An internal radiation dose can be received as a result of radioactive material being
taken into the body through inhalation, ingestion, absorption through the skin or
entry through a wound. A “BASELINE” bioassay may be required prior to working in
authorized areas depending on work assignment.
The methods used for internal monitoring are whole body counts (in-vivo) and
urinalysis (in-vitro) [If the radioactive materials within the body have insufficient
energy to penetrate out of the body (tritium, Strontium-90 or alpha emitters) a
“Whole Body Counter” cannot be used] to determine the amount of radioactive
material taken into the body, and to calculate a dose for the uptake.
Whole Body Counter Thyroid uptake system
In-vitro analysis

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A large percentage of the radionuclides which have entered the body are
eliminated in the first few days. However, a portion will be absorbed in various
organs depending on the chemical nature of the radionuclide. Iodine for
example will concentrate in the thyroid gland, whilst calcium elements
strontium, barium, radium are largely deposited in the bone. The most
important factors to determine the total radiation dose delivered to the target
tissue by the radionuclide is in the body are:
• The amount of radioactive material deposited.
• The type and energy of the radiations emitted.
• The length of time it remains in the body, known
as the Effective Half-life (TE).
This effective half-life depends on two factors, the radioactive decay of the material
(TR) and the rate at which it is eliminated from the body by biological processes (. The
biological half-life is the time taken for the body to reduce the amount of a deposited
element to half its initial value by natural processes. The effective half-life is the time
taken for the amount of a specified radionuclide in the body to decrease to half its
initial value as a result of both radioactive decay and natural elimination.
Biological (TB) and Effective Half-Life (TE)
Terminology Related to Internal Contamination- 13

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Dose Calculation for Airborne Contamination-1
Exposure from Contamination There are two radiological modes of exposure from
contamination. Contamination may cause an external and/or internal hazard. In both
cases, the amount of dose received is highly dependent on the type(s) of radiation
emitted by the material. Contaminants can generally be divided into two groups –
charged particle emitters (i.e. alpha or beta) and non-charged particle emitters (i.e.
gamma-only). Alpha or Beta emitters deliver more dose to the exposed tissue than
materials which emit only gamma radiation.
External Exposure For a gamma-only emitter, the dose received is due to the gamma
radiation from the material. The following rule of thumb can be used to estimate the
gamma dose received:
• 1 Curie = 2.22 x 1012 dpm
• 1000 dpm/100cm2 = 4.5 x 10-10 Ci/100cm2 (for gamma contaminator)
Internal Exposure is controlled based on a limit for the amount of radioactive
material taken into the body in a year. Each radionuclide has a specific limit called
the Annual Limit of Intake (ALI).
The ALI is the amount of a radionuclide which, if taken into the body, would result in
a dose equal to the maximum allowable annual dose for the organ(s) of concern. For
instance, the ALI for Co-60 is 10 uCi – this would result in an effective dose to the
whole body of 20 mSv.

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Airborne Contamination Detection- 2
Personal Air Sampler Portable Air Sampler Fixed Air Sampler
Portable Detector HPGe Detector

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Area/Equipment Contamination Control- 1
Spill
A spill is defined as an uncontrolled release of radioactive material. This could
possibly be in the form of liquid or dry. In the event of a spill, it is important to
remember the following acronym: SWIM’N
• S Stop the source or spread of the spill – for example, upright an overturned
container, close a valve, place absorbent material around the area
• W Warn others in the area
• I Isolate the area – close doors or use convenient items to form a barrier
• M Minimize your exposure – complete initial steps and move away from the
area
• N Notify radiological control personnel ASAP
It is important to note that these steps do not have to be performed in a
certain order. The best advice is to use your initial instinct if you confront a
spill.

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Area/Equipment Contamination Control- 2
INSTRUMENTS TO DETECT CONTAMINATION
Contamination can only be detected with either a wipe test using a liquid
scintillation counter or a gamma counter, or an area survey using a survey meter,
depending on which radionuclides are present and if it is fixed or removable
contamination.
Survey meters cannot be used to survey for removable contamination. This can
only be done with a wipe test. However, a wipe test can not be used to evaluate
an area of fixed contamination. This can only be done with a survey meter.
Swab Sample for Wipe Test

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DECONTAMINATION
• Personal Decontamination
• Area/Equipment Decontamination

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• Decontamination is the removal of radioactive contamination from
the unexpected places (person, object or place).
Personnel Decontamination:
External decontamination during a radiation emergency
Personal Decontamination- 1
It is important to get radioactive material off your body as
soon as possible to lower your risk of harm.
1. Remove outer layer of clothing.
•Take off your outer layer of clothing: Taking off your outer layer of
clothing can remove up to 90% of radioactive material.
•Be very careful in removing your clothing to prevent radioactive dust
from shaking loose. Put the clothing in a plastic bag and put the bag
in an out-of-the-way place, away from other people and pets.
2. Wash yourself off.
• Take a warm shower and gently wash yourself with lots of soap. Do not
scrub, or scratch your skin. Your skin protects the inside of your body RMs.
• Wash your hair with shampoo or soap. Do not use conditioner because it
will cause radioactive material to stick to your hair.
• Keep cuts and abrasions covered when washing to keep from getting
radioactive material in open wounds.
3. Put on clean clothes
Clothes in drawer away from radioactive material are safe to wear.

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Personal decontamination:
External decontamination of an organ is normally accomplished using
mild soap and lukewarm water. This procedure is highly effective for
small, localized areas of contamination.
The method is:
•Wash, dry, then resurvey. The organ/area should be washed with
soap, lukewarm water & clean gauze sponge.
•The gauze should be wet with the cleaning solution, the affected area
gently scrubbed, and the gauze disposed of.
• The affected area should next be dried thoroughly.
• Finally, when the drying is complete, the area should be resurveyed
to check the efficacy of the decontamination efforts.
• If contamination persists but the amount has decreased, continue
using the same solution.
• If three successive washings do not result in a significant decrease,
progression to a different cleaning solution is needed.

Emergency Management of Radiation Causalities
CAUTION

Initial Management of Externally Contaminated Patient
• Gross Decontamination
– Removal of Contaminated Clothing
– Washing and removal of Contaminated Hair
– Removal of Gross Wound Contamination
• Intermediate Stage (at clean location, if necessary)
– Removal of Contaminated Clothing
– Further Local Decontamination, Swabs of Body Orifices
– Supportive Measures, First Aid
• Final Stage
– Patient Discharged with Fresh Clothing
– More Definitive Decontamination (surgical) and Other
Therapy at Dispensary or Hospital

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Internal Decontamination
• Radionuclide-specific
• Most effective when administered early
• May need to act on preliminary information
Radionuclide Treatment Route
Cesium-137 Prussian blue Oral
Iodine-125/131 Potassium iodideOral
Strontium-90 Aluminum phosphate Oral
Americium-241/ Ca- and Zn-DTPA IV/or
Plutonium-239/ nebulizer
Cobalt-60
Questions regarding indications for therapy, onset
and type of treatment, and immediate and long-
term follow-up should be directed to a specialist.

57
Area Decontamination- 1
WIPE TESTING
Wipe testing involves the swabbing of areas of a laboratory to determine
if removable contamination exists. Swabbing may be done with filter
paper or any other dry absorbent material. Each wipe must cover at least
100 cm2 of area.
The swabs, or "wipes" are then counted in either a liquid scintillation
detector or a gamma counter.
Minor spills on benches and floors
1. Demark the affected area.
2. Wear disposable gloves and overshoes if necessary. Change these at
intervals if they become contaminated.
3. Drop paper tissues/towels on the affected area to limit the spread of
contamination.
4. Mop up spilled material, working from periphery inwards. Wash affected
area placing contaminated towels in plastic bags.
5. Monitor surface and repeat washing if necessary.
6. Report incident to RCO.
7. Assess amount and cause of accident.

58
Decontamination: Equipment- 1
EQUIPMENT DECONTAMINATION PROCEDURE
1. Applicability
This procedure applies to all refrigerators, freezers, animal cages, and other equipment,
which have contained radioactive materials or were used for radioisotope research.
2. Safety Precautions
Wear your lab coat, double gloves and goggles. If a gamma/x-ray or strong beta energy
emitting radionuclide was used/stored, be sure to wear whole body and ring TLDs. Be
prepared to collect the excess water used for cleaning by putting trays or paper towels
under the equipment.
• Dispose of all cleaning materials as radioactive waste.
• Remove your gloves and lab coat at the end of the work.
• Wash your hands before leaving the laboratory.
3. Preliminary preparations
I. Remove all loose materials from the equipment. If the materials are for disposal be
sure to follow the appropriate disposal procedure for each type of material (non-
hazardous, hazardous, radioactive, chemical, biological).
II. Clean the equipment using water and a mild detergent. Collect the water and check it for
contamination. To do so, put 0.5 ml of water in a scintillation vial, add 5 ml of scintillation
fluid and measure the vial using a LSC (Liquid Scintillation Counter).

59
3. If the water used for cleaning is contaminated dispose of the water as liquid radioactive
waste. Be sure to use the appropriate liquid waste container depending on the half-life
of the radionuclide used/stored in the equipment. Repeat step 2.
4. If the water used for cleaning is not contaminated, dispose of it to the drain.
4. Decontamination
If after washing using water and mild detergent, the measurement still indicates a level of
radioactive contamination above the criteria, proceed with more aggressive
decontamination. To do so:
1. Use physical agents such as brushes or abrasive materials. Press hard on the
contaminated surface using a circular motion. Start from the outside of the
contaminated area and work towards the middle to prevent spreading the
contamination.
2. Use chemical agents (decontamination solutions or ion exchange agents).
3. After using chemical or physical agents, wash again with clean water, allow the surface
to dry and measure the contamination.
4. If the surface is still contaminated, the contamination will be considered fixed. In this
case contact the Radiation Control Officer. A RCO will measure the level of the radiation
field and make recommendations for the future use or disposal of the equipment.
Decontamination: Equipment- 2

Contaminated
Waste
Waste
Decontamination Treatment Area Layout
Radiation
Survey
HOT
LINE
STEP
OFF
PAD
CONTAMINATED
AREA
BUFFER
ZONE
CLEAN
AREA
Radiation
Survey
&
Charting
ED
Staff
Clean
Gloves, Masks,
Gowns, Booties
Separate
Entrance
Trauma Room
CAUTION

61
Decontamination Kits- 1
Decontamination kit
A decontamination Kit is a complete set decontamination materials. The
decontamination kit should comprise the following items:
 Decontamination solution or gel
 Protective clothing
 Plastic overshoes
 Plastic aprons or disposable oversuit
 Box disposable gloves
 Disposable face masks
 Large red polythene and smaller specimen bags
 Roll paper towel, paper tissues
 Small forceps or remote handling tools
 Adhesive radioactive warning tape and notice
 Barriers, or ropes for separating affected area
 Soap
 Detergent
 Soft nail brush
 Eye wash
 Notebook, labels and pen

62
Decontamination Kits- 2
Iodowash
Radioactive Iodine Decontamination
Solution- Used for decontamination of
radioactive iodine from nuclear fallouts
and medical facilities.
• Iodowash decontaminates all surfaces
and is gentle enough for use on intact
skin.
Thank You Very Much!

64
The Effective Half-life TE is given by
TR is the radioactive half-life and TB is the biological half-life.
For example, Tritiam (H-3) has a TR of 12.3 yrs and TB of 10 days. So the
value of TE for H-3 is slightly less than 10 days. For the Strontium Sr-90
TR is 28 yrs and TB is 50 yrs giving the value of TE of about 18 yrs. TE is
always less than TR or TB.
Serious internal hazards are presented by those radionuclides which
have long half-lives. Once deposited in the body they remain there,
essentially unchanged in amount, during the lifetime of the individual.
The continued action of the emitted particles can cause significant injury
because they deposit their energy for years in a limited region.
Biological and Effective Half-Life
Terminology Related to Internal Contamination- 15

Radiation Basics: Nuclear Radiation & Radioactivity
Derived Air Concentration is The concentration of a
given radionuclide in air which, if breathed by the
reference man for a working year of 2,000 hours
under conditions of light work (with an inhalation
rate of 1.2 cubic meters of air per hour), results in
an intake of one annual limit on intake (ALI).
The DAC is the activity concentration in air in units
of Bq/m3.
The DAC is obtained by dividing the ALI by the
volume of air breathed by an average worker
during a working year (2400 m3). The DAC is the
average airborne concentration that a radiation
worker may be exposed to for 40 hours/week,
50 weeks/year.
The ALI is the smaller value of intake of a given
radionuclide in a year by the reference man that
would result in either a committed effective dose
equivalent of 5 rems (0.05 sievert) or a committed
dose equivalent of 50 rems (0.5 sievert) to any
individual organ or tissue.

Radioactive Contamination and Procedures of Decontamination

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