Transcript Slide 1

Radiation Safety Training
ALARA
Washington State University
Radiation Safety Office
The Guiding Principle and Philosophy of Radiation
Safety is:
ALARA
(As Low As Reasonably Achievable)
It is also a regulatory requirement!
So what does ALARA mean ?
ALARA is an acronym for As Low As
Reasonably Achievable. This is a radiation
safety principle for minimizing radiation doses
and releases of radioactive materials by
employing all reasonable methods.
ALARA is not only a sound safety principle,
but it is also a regulatory requirement for all
radiation safety programs.
What is the basis for ALARA ?
Current radiation safety philosophy is based on
the conservative assumption that radiation dose
and its biological effects on living tissues are
modeled by a relationship known as the “Linear
Hypothesis”.
The assertion is that every radiation dose of any
magnitude can produce some level of detrimental
effects which may be manifested as an increased
risk of Genetic mutations and cancer.
RADIATION DOSE/RESPONSE MODELS
 Two models:
(1) Linear
2) Threshold
 Preferred (Regulatory) model is Linear No-Threshold Dose Model:
Biological Response
Biological Response
 Conservative Hypothesis - For any dose, no matter how small, there is some
effect, and as the dose is increased, the effect also is increased in proportion.
Dose
Dose
Threshold
How is ALARA Implemented ?
 An effective ALARA program is only possible when a
commitment to safety is made by all those involved. This
includes the Radiation Safety Office staff, the
Radiation Safety Committee, research faculty and all
radiation workers. The WSU Radiation Protection
Program Manual provides the guidelines for the
Responsibilities and good practices which are consistent
with both the ALARA concept and the regulatory
requirements of the Washington State Administrative
Code (Title 246 Chapter 220-254).
WSU radiation safety program.
 The WSU radiation safety program attempts to lower
doses received by radiation workers by utilizing
practical, cost effective measures.
How do we do this?
With the 4 basic Radiation Protection Principles.
 Time
 Distance
 Shielding
 Contamination Control
T IM E
EXPOSURE
Decreasing the amount of time near the source decreases
your exposure.
How do you decrease your time
exposure?
 Plan and Set Up Your Experiment Before Using
Radioactive Materials.
 Perform Dry Runs - (Use NO Radioactive Material).
 Practice Handling Techniques (pipetting/aliquotting).
 Work Quickly but Safely.
NCE
DISTA
EXPOSURE
Increasing the distance from the source decreases your
exposure.
Attenuation of Radiation Intensity with Distance
Increasing the distance from a source from
3 feet to 10 feet reduces the radiation intensity
by 91%.
Increasing the distance from a source from
3 feet to 32 feet reduces the radiation intensity by
99.9912%.
Increasing the distance from a source from
3 feet to 60 feet reduces the radiation intensity by
99.9975%.
Inverse Square Law 1/(distance)2
If you double the distance from a point source of
radiation, the exposure is reduced to ¼ the intensity
at the closer distance.
---------------------- I1 (100 mR/hr)
D1 (1 meters)
-------------------------------------------------------------------- I2(?)
D2 (8 meters)
Given: I1 = 100 mR/hr
D1 = 1 meters
D2 = 8 meters
I2 = (d1)2 X I1
(d2)2
= 1.6 mR/hr
DING
SHIEL
EXPOSURE
Increasing the amount of shielding
decreases your exposure.
Proper thickness and appropriate materials are
critical to shield you from a radiation hazard.
Shielding Examples
SHIELDING
Appropriate Shielding


High "Z" Materials (Pb) for photons
Low "Z" Materials (Acrylic or Plexiglas) for beta radiation
Using Storage Containers (pigs)

Shipping Containers from RAM
Suppliers
Using Local Shielding (Plexiglas L-Blocks & Pb - Bricks)
Using Vial & Syringe Shields –
Balance between shielding and time. (If it takes a long time to
insert RAM into a shield it may not be ALARA!)
CONTROLLING EXTERNAL HAZARD
 TIME: Radiation dose is proportional to the
duration of the exposure.
 DISTANCE: Radiation dose is proportional to
1/(Distance)2.
 SHIELDING: Radiation dose is determined by
the type and thickness of shielding materials used.
Correct selection of Shielding Materials
are a function of type and energy of radiation.
So how do we control the internal
hazard?
By Contamination Control
 The major hazard for most radioactive materials on
the WSU campus comes from internalizing the
radioactive material.
 Once the radioactive materials are inside your body,
you lose all the protections from TIME, DISTANCE
AND SHIELDING.
 Contamination Control is the key to preventing
internalization of radioactive materials.
Radionuclides can enter the
body in four ways.
Inhalation, ingestion, absorption through the skin and wounds.
Contamination Control
 Protect Yourself
Wear gloves properly.



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Always use protective clothing.
Lab Coat
Gloves
Eyewear
Don’t dress like this guy!
Required by WAC 246-235-130
Lab Coats can be
very fashionable. But
always wear long
pants and full shoes.
The hat is optional.
CONTAMINATION CONTROL
 Always WEAR your lab coat and gloves, including
appropriate leg and foot covering.
Required by WAC 246-235-130
Wear safety glasses/goggles or a face shield
when working with unsealed RAM. These
precautions are especially important when
there is a splash potential.
CONTAMINATION CONTROL
(continued)
 CHANGE gloves frequently and REMOVE
them when leaving the lab and dispose of
them as radioactive waste. To control cross
contamination of yourself, others and
other research items.
Protect Others
 If you contaminate your lab partners.
They will not be happy with you.
 Label your radioactive work area.
Required by
WAC 246-235-130
Protect Others (cont.)
 Label containers and tools used in radioactive
work.
Required by
WAC 246-235-130
Contamination Control (cont.)
 Protect Facilities and Equipment
 Cover all radioactive work areas
with absorbent paper, including
any transfer trays or secondary
containers.
Tape off the work area.
Required by WAC 246-235-130
Check for Contamination
(do surveys)
CONTAMINATION CONTROL
(continued)
 Store and transport liquid radioactive materials in
SECONDARY CONTAINERS, with the capacity to contain
potential spills.
- USE DOUBLE CONTAINMENT –
FOOD and DRINK
 NO eating, drinking, smoking, or chewing in the radioactive
work space. (Internal contamination)
 Do not store food, drink or personal effects in any area,
container, or refrigerator designated for radioactive materials
use or storage. Required by WAC 246-235-130
The presence of empty food and drink
containers in the lab will constitute
a violation of regulations, since it will
be inferred that consumption occurred
on the premises.
CONTAMINATION CONTROL
(continued)

NO mouth pipetting. (Internal contamination)
 Required by WAC 246-235-130


MONITOR hands, clothes and work area
frequently during and after each use.
 Always WASH hands
at the completion of
radioactive work.
ADDITIONAL RADIATION SAFETY PRECAUTIONS
 Work with volatile compounds in a CERTIFIED
OPERATIONAL fume hood. The hood must also be labeled
for radioactive materials use.
- Operational parameters of the fume hood
must be verified before you begin your
radioactive work.
CONTROLLING INTERNAL HAZARD
To minimize the uptake of radionuclides into the body
control the “Routes of Entry”
Inhalation:
Use of fume hood, gloved boxes.
Gases and vapors in experiments.
Radioactive spill of volatile compounds.
Opening of sealed vials.
Ingestion:
No eating, drinking, chewing, smoking or
application of cosmetics in radioactive laboratories.
Use of gloves (preferably double gloves).
No food in radioactive refrigerators.
Washing hands, do monitoring.
Prohibit mouth pipetting.
Absorption:
Wear protective clothing (lab coat, full shoes;
be aware of loose sleeves of lab coat).
On November 1, 2006, Alexander Litvinenko
suddenly fell ill and was hospitalized.
He died three weeks later of polonium-210 induced acute radiation
syndrome. The median lethal dose for polonium-210 is around 238 μCi
or 50 nanograms in the case of ingestion. The polonium-210 was in his
tea.
Polonium-210 is an alpha emitter. As we have seen in
another module, alpha radiation is the highest internal
hazard. If Mr. Litvinenko had not ingested the polonium it
would not have been a radioactive hazard to him. The alpha
radiation emitted by the polonium would not have
penetrated the layer of dead skin on his body.
So keep your lab clean.
Do your surveys.
NO eating, drinking, smoking, or chewing
in the radioactive work space.
Do not store food, drink or personal
effects in any area, container, or
refrigerator designated for radioactive
materials use or storage.
Test Time!
 Follow this link to the test.
https://myresearch.wsu.edu
 Use your WSU user name and password to sign in.
 Click on the training tab.
 Then click on the available training tab
 Find the radiation safety training alara course, in the
OR section, click on it and take the test.