radiation protection principle , kuala lumpur

radiation protection principle

1. National Committee for the Certification of
Radiation Protection Officer
RADIATION PROTECTION RADIATION PROTECTION
PRINCIPLESPRINCIPLES

2. National Committee for the Certification of Radiation Protection Officer
1. Introduction1. Introduction
3. Radiation Protection Systems 3. Radiation Protection Systems
5. Protection Against Radiation Hazards 5. Protection Against Radiation Hazards
4. Intervention4. Intervention
2. Objectives of Radiation Protection2. Objectives of Radiation Protection
6. References6. References
Contents

3. National Committee for the Certification of Radiation Protection Officer
Radiation protection principles are related
to the source and individual.
•Proposed and continuing practice that
cause exposure,
•Intervention that reduces exposure.
Both systems are used in three types of
exposures, i.e. workers, medical and public.
There are two systems of radiation protection;
IntroductionIntroduction

4. National Committee for the Certification of Radiation Protection Officer
Prevent the occurrence of deterministic
effect by restricting doses to individuals
below the relevant thresholds.
Reduce induction of stochastic effect.
Deterministic effect is the effect where the intensity of
effect increases with dose. There are thresholds for
deterministic effects.
Stochastic effect is the probability of occurrence is
proportional to the dose. No threshold can be invoked
for them.
Objectives of Radiation ProtectionObjectives of Radiation Protection

5. National Committee for the Certification of Radiation Protection Officer
Justification of Practice
Optimization of Protection and Safety
Dose Limit
3 Principles used in Radiation Protection
Systems:
Radiation Protection SystemsRadiation Protection Systems

6. National Committee for the Certification of Radiation Protection Officer
In proposed and continuing practices, the
justification of practice must be such that the
work uses radiation because it gives benefit (or
gain) to the exposed individuals or to society
that exceeds radiological risk.
Justification of PracticeJustification of Practice
Justification in intervention provides more
benefit in comparison to if there were no
intervention.
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7. National Committee for the Certification of Radiation Protection Officer
Optimization of Protection and SafetyOptimization of Protection and Safety
Based on the principles of ALARA (As Low As
Reasonably Achievable).
For any given radiation source within a practice,
the magnitude of individual doses, the number of
people exposed, and the likelihood of incurring
exposures should be kept to as low as reasonably
achievable, taking economic and social factors
into considerations.
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8. National Committee for the Certification of Radiation Protection Officer
Dose LimitDose Limit
Dose limit is used to apply controls on each
individual’s accumulation of dose.
•a line of demarcation between “safe”
and “dangerous”,
•the sole measure of the stringency of
a system of protection.
Dose limits do not include medical exposures
and natural background radiation.
Dose limits are not :
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9. National Committee for the Certification of Radiation Protection Officer
radiation workers;
members of the public;
trainees of radiation;
planned special exposures; and
female pregnant workers.
Annual Dose Limits (ADLAnnual Dose Limits (ADL))
There are different categories of dose limits
for :
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10. National Committee for the Certification of Radiation Protection Officer
Application ADL (mSv)
Annual dose limit for the whole body exposure of
worker
20
Female pregnant worker: dose to the foetus
accumulated over the period of time between
confirmation of pregnancy and the date of birth
< 1
Partial body exposure of a worker :
i. Limit for the effective dose-equivalent
ii. Limit on average dose in each organ or tissue
iii.Limit for lens of the eyes
iv.Limit on equivalent dose for the hands and feet
50
500
150
500
1. ADL for Occupational Exposure
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11. National Committee for the Certification of Radiation Protection Officer
Application ADL (mSv)
Dose limit for the whole body exposure 1
Average dose for lens of the eyes 15
Average dose for the skin 50
Effective dose limit for a person who knowingly assits
in the support of a patient during the period of
diagnostic examination or treatment of the patient
< 5
Effective dose limit for a person below the age of 16
years visiting patient undergoing treatment or
diagnostic examination
< 1
2. ADL For Exposure of Members of Public
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12. National Committee for the Certification of Radiation Protection Officer
3. Dose Limit for Apperentice and Students
Apprentices and students in radiation work (in a
supervised or controlled areas) must not be less
than 16 years old.
Application In a calendar year
(mSv)
Dose limit for the whole body exposure 6
Average dose for lens of the eyes 50
Equivalent dose to the extremities 150
Equivalent dose to the skin 150
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13. National Committee for the Certification of Radiation Protection Officer
i. Allowed only in situations when alternative techniques,
which do not involve such exposure, cannot be used.
Dose Limit in Special CircumstancesDose Limit in Special Circumstances
Refers to voluntary exposure during normal operation
whereby one or more of the annual dose limits for a worker
are likely to be exceeded.
iii. Temporary and is subjected to review by the
appropriate authorities
ii. Shall be carried out when approved by the appropriate
authorities (i.e. AELB or the Ministry of Health of
Malaysia).
Conditions
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14. National Committee for the Certification of Radiation Protection Officer
•an emergency situation occurred;
•a directive issued by appropriate authority in any other
temporary exposure situation to reduce or avert temporary
exposures;
•the appropriate authority directs the remedial action to
reduce or avert chronic exposure as specified by them.
4. Intervention4. Intervention
The form, extent and duration of intervention shall be
optimized to produce the maximum net benefit in the social
and economic circumstances.
InterventionIntervention is carried out when:
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15. National Committee for the Certification of Radiation Protection Officer
Made based on engineering as well as administrative controls.
5. Protection Against Radiation Hazards 5. Protection Against Radiation Hazards
Working areas may be classified according to :
clean area,
supervised area &
controlled areas.
One method of control against radiation hazard employing both
engineering and administrative controls is through the classification
of areas.
Classification of areas take into account
the likelihood and magnitude of potential
exposures (risk) and the nature and extent
of the required protection and safety
procedure.
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Clean Area Clean Area
Work area where the annual dose
received by a worker is not likely to
exceed the dose limit for a member of
the public.
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Work area for which the occupational exposure
conditions are kept under review even though
specific protective measures and safety provisions
are not normally needed.
Supervised AreaSupervised Area
Area is clearly demarcated with radiation warning
signs and legible notices clearly posted.
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18. National Committee for the Certification of Radiation Protection Officer
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Work area where specific protection measures and safety
provisions could be required for controlling normal
exposures or preventing the spread of contamination
during normal working condition and preventing or
limiting the extent of potential exposures.
Controlled AreaControlled Area
Annual dose received by a worker in this area is likely
to exceed 3/10 Annual Dose Limit.
Area is clearly demarcated with radiation warning signs and
legible notices clearly posted.
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19. National Committee for the Certification of Radiation Protection Officer
Control Against External ExposureControl Against External Exposure
Three methods of radiation protections that can
be used - shielding, time and distance
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20. National Committee for the Certification of Radiation Protection Officer
Shielding
Quality of radiation refers to type of radiation, its energy,
the flux and dimension of source.
Material may be used to attenuate radiation and
thus provide shielding against external exposure.
Shielding takes into consideration
•the density and thickness of shielding materials,
•the quality of radiation.
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21. National Committee for the Certification of Radiation Protection Officer
Selection of shield depends on the types of radiation.
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•Alpha particles lose energy rapidly in passage through
matter and hence do not penetrate far. No shielding is
required against alpha particles.
•Beta particles do not lose energy so rapidly compared to
alpha particles, and are therefore more penetrating.
Materials composed of elements of low atomic number
such as Perspex and aluminum and thick rubber are most
appropriate for the absorbance of beta particles.
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22. National Committee for the Certification of Radiation Protection Officer
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•Neutrons are uncharged particles and can penetrate matter
considerably. Shields use on neutron is directed towards
reducing the energy of the neutrons to levels that can easily be
absorbed
Neutron (< 1 MeV)
A reduction of the energy of neutron is best accomplished
by collisions with atoms of light elements, e.g. hydrogen.
 Neutrons (> 1 MeV)
Energy of fast neutrons is best reduced using water and
paraffin wax. 20 cm of paraffin wax will attenuates 1 MeV
fast neutrons by a factor of 10
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23. National Committee for the Certification of Radiation Protection Officer
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Attenuation of x-and gamma-rays require the use
of high atomic number materials. The most
suitable material is lead and iron.
In the medium energy range (0.50 – 0.75 MeV)
the density of the material is more important than
the atomic number. At higher and lower energy
ranges, materials of higher atomic number are
more effective.
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24. National Committee for the Certification of Radiation Protection Officer
Comparison Comparison
- types of radiation and shielding required
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25. National Committee for the Certification of Radiation Protection Officer
Time
The longer the exposure time the higher is the
dose received and vice versa.
Dose = Dose rate x time
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26. National Committee for the Certification of Radiation Protection Officer
Distance
Reduction of radiation dose inversely proportional
the square of the distance or it follows the inverse
square law equation.
where I
1
and I
2
are radiation intensities at
distances d
1
and d
2
respectively.
I
1
I
2
=
d
1
d
2
2
2
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27. National Committee for the Certification of Radiation Protection Officer
There are three modes of entry by radionuclides into the
body; i.e. inhalation, ingestion and penetration through the
skin.
Control of Internal ExposureControl of Internal Exposure
Protection against such radiation hazards may be
overcome through:
Internal exposure is attributed to radiation exposures from
radionuclides inside the body.
the use of personal protective equipment,
having proper facilities to handle unsealed sources
having procedures to safely handle them.
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28. National Committee for the Certification of Radiation Protection Officer
•Worn by radiation workers to reduce the risk of
radiation exposure from internal radiation
exposure and radioactive contamination.
Radiation Personal Protective Equipment (PPE)Radiation Personal Protective Equipment (PPE)
•The last line of defense in controlling risk from
ionizing radiation.
•Since the radiation hazards still exist, PPE
should only be used to complement other means
of radiation hazard control already in place.
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29. National Committee for the Certification of Radiation Protection Officer
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Examples of personal radiation protection equipments/
clothing include:
 Laboratory coat
 Overall or boiler suit
 Rubber gloves
 Overshoes
 Rubber boots
 Breathing apparatus
(example - Pressurized clothing, SCABA + whole
body suit (Self Contained Breathing Apparatus))
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30. National Committee for the Certification of Radiation Protection Officer
Safety Equipment And Facilities At The Place Of Work Safety Equipment And Facilities At The Place Of Work
Safety facilities include building design incorporating safety
features to handle radiation and radioactivity. Examples of such
equipment and facilities are:
These equipments are not worn by workers but are used by
them to reduce exposure and contamination.
•Remote-handling tongs
•Lead brick
•Liquid transfer system
•Radioactive containers
•Ventilated facility
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31. National Committee for the Certification of Radiation Protection Officer
Safety Procedures and Surveillance Safety Procedures and Surveillance
Safety procedures employed in work related to
handling unsealed sources must stress the importance
of preventing inhalation, ingestion and penetration of
radionuclides through the skin, and contamination of
personnel and working areas in normal routine
procedure and emergency situations.
Handling of unsealed sources increases the risk of
internal radiation exposure and contamination.
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32. National Committee for the Certification of Radiation Protection Officer
Having a safe working procedure does not guarantee its
compliance. Surveillance of compliance and monitoring of
radiation levels must be carried out periodically. Both visual
surveillance and those using radiation monitoring and detectors
must be used.
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33. National Committee for the Certification of
Radiation Protection Officer
Summary

34. National Committee for the Certification of
Radiation Protection Officer
Thank YouThank You
for your attention