Radiation safety

1. Radiation Hazards and
its protection
Dr.Rabia Shah

2. 2013
Sources of RadiationSources of Radiation
Elements such as thorium, uranium, radium, RN-222,
and K-40 are naturally occurring radioactive elements
that can be found in our everyday lives.
These elements can be found in:
– rocks, soil and building materials
– food and water
Some sources are a result of ground nuclear testing,
which is not naturally occurring.

3. 2013
Cosmic and Atmospheric Cosmic and Atmospheric
RadiationRadiation
Cosmic and atmospheric radiation originates from
the sun and stars.
Earth’s atmosphere is very effective in shielding
cosmic radiation, but variations in the density of the
atmosphere can result in uneven distribution of
protection.

4. 2013
Additional Sources of RadiationAdditional Sources of Radiation
Our bodies contain naturally occurring radioactive
elements, such as potassium.
Some consumer products, such as luminous dial
watches and smoke detectors, contain small amounts of
radioactive material.

5. Cosmic radiation can be accumulated through
one cross-country airplane trip.
Tobacco leaves absorb naturally occurring
radioactive materials from the soil and fertilizers
used to grow them.
Hospitalized individuals who undergo medical
procedures are exposed to sources of ionizing
radiation.
2013

6. Annual Dose from
Background Radiation
Total US average dose equivalent = 360 mrem/year
Total exposure Man-made sources
Radon
Internal 11%
Cosmic 8% Terrestrial 6%
Man-Made 18%
55.0%
Medical X-Rays
Nuclear
Medicine 4%
Consumer
Products 3%
Other 1%
11%

7. 2013
Ionizing radiation is produced by the natural decay of
radioactive material.
Beta, gamma, and x-rays are forms of ionizing
radiation that are often used in research.
Ionizing RadiationIonizing Radiation
Beta, gamma, x-rays
remove electrons
from atoms
(Ionization).
Ions are created,
which are more
chemically
reactive than
neutral atoms.
Ions can form
compounds that might
interfere with cell
division and metabolism
or cause chemical
changes in tissue.

8. 2013
X-Rays & Gamma RaysX-Rays & Gamma Rays
X-rays and gamma rays make up part of the
electromagnetic spectrum.
They can travel forever until they hit an object and
one of three reactions occurs:
Absorption
Transmission
Scattering

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Penetrating RadiationPenetrating Radiation
-X-Rays & Gamma Rays--X-Rays & Gamma Rays-
X-rays and gamma rays can penetrate the body and
irradiate internal organs.
Exposure can result in external and internal doses.
Internal exposure can occur when rays are ingested,
inhaled, or absorbed through the skin.

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Beta ParticlesBeta Particles
Beta particles are excess electrons.
Particles can be low or high energy emitters.
Low energy emitters can be shielded by cardboard.
High energy emitters need a more dense shielding
material, such as Plexiglas.

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Non-Penetrating RadiationNon-Penetrating Radiation
-Beta Particles--Beta Particles-
Can not penetrate the body to irradiate internal
organs.
Can penetrate dead outer-layer of skin and result in
damage to live skin cells.
Can cause damage to eye lenses.
Ingestion, inhalation, or absorption through the skin
might result in internal exposure.

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Radiation Absorbed DoseRadiation Absorbed Dose
-RAD--RAD-
RAD is a unit of measurement used to describe the
amount of energy transferred from a source of ionizing
radiation to any material, including human tissue.
It is the quantity of radiation received by a patient.
As a unit of exposure, 1 rad means that each gram of air at 0° C and
1 atmosphere has absorbed 100 ergs of energy.
As a unit of dose, 1 rad means that each gram of exposed tissue has
abosorbed 100 ergs of energy.

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Radiation Equivalent ManRadiation Equivalent Man
-REM--REM-
Different types of ionizing radiation cause differing
degrees of biological effects even when the same level of
energy is transferred (same number of ergs).
Rem is used to express the quantity of radiation received
by radiation workers and populations.
The rate at which an individual is exposed also
influences the level of biological harm.
Dosimeter are used to measure a dose equivalent.

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Biological Effects of radiationBiological Effects of radiation
Exposure above permissible levels may result in:Exposure above permissible levels may result in:
Somatic Effects
Physical effects
May be immediate or delayed
Genetic Effects
Birth defects due to irradiation to reproductive
cells before conception
Teratogenic Effects
Cancer or congenital malformation due to
radiation exposure to fetus in utero

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Biological EffectsBiological Effects
-Threshold--Threshold-
Threshold effects might occur if an individual receives
a dose above the threshold level.
Acute Radiation Syndrome: large whole body dose in a short time
Effects occur at 100 rad
Radiation-induced cataract formation
Acute effects occur at 200 rad
Chronic effects occur at 800 rad
Other thresholds
Severe skin injury occurs at 1,500 rad
Teratogenic effects occur at 20 rad

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Biological EffectsBiological Effects
-Non-threshold--Non-threshold-
Non-threshold effects might occur from any amount
of exposure to radiation.
Chance of effect occurrence is proportional to the received dose.
Severity of effects are not necessarily related to exposure level.
Chance effects include:
Cancer - estimated to be 5 deaths per 10,000 persons, whom each

received 1,000 mrem
Genetic effects

17. Summary of Biological
Effects of Radiation
Radiation may…
•Deposit Energy in Body
•Cause DNA Damage
•Create Ionizations in Body
•Leading to Free Radicals
Which may lead to biological damage

18. Radiation Effects on Cells
Radiosensitivity Theory of Bergonie &
Tribondeau (1906).
Stem cells are radiosensitive, mature cells are
radioresistant.
Younger tissues are radiosensitive.
Tissues with high metabolic activity are
radiosensitive.
A high proliferation rate and a high growth rate
result in increased radiosensitivity.

19. Response to radiation depends
on:
Total dose
Dose rate
Radiation quality
Stage of development at the time of
exposure

20. Whole Body Effects
Acute or Nonstochastic
•Occur when the radiation dose is large enough to
cause extensive biological damage to cells so that
large numbers of cells die off.
•Evident hours to a few months after exposure (Early)
•Skin burns

21. Late or Stochastic (Delayed)
•Exhibit themselves over years after acute exposure.
•Radiation induced cancers
•Leukemia
•Genetic effects
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22. Low SensitivityLow Sensitivity
Mature red blood cellsMature red blood cells
Muscle cellsMuscle cells
Ganglion cellsGanglion cells
Mature connective tissuesMature connective tissues
Intermediate SensitivityIntermediate Sensitivity
Gastric mucosaGastric mucosa
Mucous membranesMucous membranes
Esophageal epitheliumEsophageal epithelium
Urinary bladder epitheliumUrinary bladder epithelium
High SensitivityHigh Sensitivity
Primitive blood cellsPrimitive blood cells
Intestinal epitheliumIntestinal epithelium
SpermatogoniaSpermatogonia
LymphocytesLymphocytes
Radiosensitivity of cells

23. Radiation Protection

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When working with radioactive
material, remember to minimize your
exposure at all possible times.
Minimize Exposure

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Measure Your Radiation Dose
-Dosimeters-
Use to measure the occupational dose equivalent from x-ray,
gamma, and high energy beta emitters. Dosimeters cannot
detect radiation from low energy beta emitters.
Luxel Ring Dosimeter Fetal Dosimeter
Measures…Whole body exposureExtremity exposureExposure to a fetus
Is worn… On the torso or area of
highest likely exposure
On either hand under the
gloves with the name
facing the radiation source
At the waist line
X-rays & gamma rays:
1 – 1,000,000 mrem
X-rays & gamma rays:
30 – 1,000,000 mrem
Can detect…
High energy beta emitters:
10 – 1,000,000 mrem
High energy beta emitters:
40 – 1,000,000 mrem

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Maximum Permissible
Dose Limits (MPD)
State and Federal regulations set maximum
permissible yearly radiation dose (MPD) limits for
adults.
Exposure up to dose limits is not expected to cause
adverse health effects.
ADULT MAXIMUM PERMISSIBLE DOSES
Whole Body – head, neck, torso, upper arms and legs 5,000 mrem
Lens of the eye 15,000 mrem
Extremities, skin, and internal organs 50,000 mrem
Declared pregnant woman 500 mrem

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As Low As Reasonably
Achievable (ALARA)
Always practice ALARA
AS LOW AS REASONABLY ACHIEVABLE

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Why Practice ALARA?
Any type of ionizing radiation poses some risk. As
exposure increases, so does risk.
Research shows that some people’s DNA is more
resistant or susceptible to damage, and some people
have an increased risk of cancer after exposure to
ionizing radiation.
Limit your exposure whenever possible.

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Three Effective Strategies
-Time-
Minimize the time and you will minimize the dose.
Pre-plan the experiment/procedure to minimize
exposure time.

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Doubling the distance from the source can reduce
your exposure intensity by 25%.
Use forceps, tongs, and trays to increase your
distance from the radiation source.
Move the item being worked on away from the
radiation area if possible.
Know the radiation intensity where you perform
most of your work, and move to lower dose areas
during work delays.
Three Effective Strategies
-Distance-

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Position shielding between yourself and the source of
radiation at all permissible times. Take advantage of
permanent shielding (i.e. equipment or existing
structures).
Select appropriate shielding material during the
planning stages of the experiment/procedure.
Plexiglas, plywood and lead are effective in shielding
radiation exposure. Use the proper shielding for the
type of radioactive material present.
Three Effective Strategies
-Shielding-

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Shielding X-Rays & Gamma RaysShielding X-Rays & Gamma Rays
Lead shielding will reduce the intensity of x-rays
and gamma rays being emitted from a source of
radiation.
To reduce exposure by a certain desired percent,
lead shielding must be a certain thickness for each
type of emitter.
Remember:
Lead shielding does not reduce exposure by 100%.

34. Room shielding
Lead lined plaster board Lead glass viewing window

35. Personal Protective Equipment
Fig 3. Overshoes
Often worn routinely in the
Radiopharmacy for sterility reasons.
Not always otherwise worn routinely
to prevent the spread of
contamination, but widely used for
this purpose following a spillage.

36. Radiation protection in X-ray

37. 2013 37
Radiation SafetyRadiation Safety
-Laboratory Rules--Laboratory Rules-
1. Smoking, eating, and drinking are not permitted in
radionuclide laboratories.
2. Food and food containers are not permitted in the
laboratory.
3. Radionuclide work areas shall be clearly designated
and should be isolated from the rest of the laboratory.
4. All work surfaces shall be covered with absorbent
paper which should be changed regularly to prevent
the buildup of contamination.

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Radiation SafetyRadiation Safety
-Laboratory Rules--Laboratory Rules-
5. Protective clothing shall be worn when working with
radioactive materials. This includes laboratory coats,
gloves, and safety glasses.
6. Dosimeters shall be worn when working with
relatively large quantities of radionuclides which
emit penetrating radiation.

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7. All containers of radioactive materials and items
suspected or known to be contaminated shall be
properly labeled with tape or tagged with the
radiation logo and the word “RADIOACTIVE”.
8. All contaminated waste items shall be placed in a
container specifically designed for radioactive
waste.
Radiation SafetyRadiation Safety
-Laboratory Rules--Laboratory Rules-

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Warning LabelsWarning Labels
Mark all items used to manipulate or store
radioactive material.
Label all contaminated items.
CAUTION:
Radioactive
Material
Remove all radiation labels
and warnings on containers
that no longer contain
radioactive material and are
not contaminated.

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MUSTMUST be clearly visible, durable, and MUSTMUST state:
““CAUTION: RADIOACTIVE MATERIAL”CAUTION: RADIOACTIVE MATERIAL”
Warning Label RequirementsWarning Label Requirements
Labels must provide sufficient information on the
container to minimize exposure and to make sure all
proper precautions have been taken.
Radionuclide(s)
Estimated activity
Date

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Radioactive Waste DisposalRadioactive Waste Disposal
Radioactive waste includes anything that contains or
is contaminated with radioactive material.
Collect radioactive waste in proper containers.
Keep containers closed and secured unless you are
adding waste.
Report the proper information on the radioactive waste
tag when material is put in the waste container.
Keep a tag on the waste container at all times.

43. THANKS
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