principles of protection

1. IAEA
International Atomic Energy Agency
Fundamental Principles of Radiation
Protection
Day 3 – Lecture 6

2. IAEA
To review the fundamental principles of
protection recommended in the
international Basic Safety Standards,
General Safety Requirements Part 3
(IAEA GSR Part 3).
Objective
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3. IAEA
The primary aim of radiation protection is to provide an
appropriate standard of protection for man and the
environment without unduly limiting the beneficial practices*
giving rise to radiation exposure.
Radiation Protection Fundamentals
*Practices are any human activity that;
• introduces additional sources of exposure or exposure pathways;
• extends exposure to additional people;
• modifies the network of exposure pathways from existing sources
so as to increase the exposure or the likelihood of exposure of people or
the number of people exposed.
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4. IAEA
The recommendations of the International Basic Safety
Standards are intended to:
• prevent the occurrence of deterministic effects (e.g.
tissue damage) by keeping radiation doses below the
relevant thresholds; and
• to ensure that all reasonable steps are taken to
minimize the risk of stochastic effects (e.g. probability of
cancer induction and of hereditary effects).
Radiation Protection Fundamentals
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5. IAEA
Managing Risk
In most national legal systems, activities not specifically
prohibited by law may be undertaken by people without
official authorization.
Only activities that pose an identifiable risk of injury to
persons or to the environment should be regulated, i.e. prior
permission or specific authorization is required before a
person can conduct that activity.
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6. IAEA
Radiation exposure poses special risks to the health and
safety of persons and to the environment. That risk must be
carefully managed by appropriate legislation.
Furthermore, as everyone in the world is exposed to ionizing
radiation from a wide range of both natural and artificial
sources, the radiation risks to people and the environment
that may arise from the use of radiation and radioactive
material must be assessed and controlled through the
application of standards of safety.
Managing Risk (Cont.…)
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7. IAEA
• These Standards establish requirements to be fulfilled in all facilities
and activities giving rise to radiation risks. For certain facilities and
activities, such as nuclear installations, radioactive waste management
facilities and the transport of radioactive material, other safety
requirements, complementary to these Standards, also apply. The
IAEA issues Safety Guides to assist in the application of these
Standards.
• Exposure of tissues or organs to ionizing radiation can induce the
death of cells on a scale that can be extensive enough to impair the
function of the exposed tissue or organ. Effects of this type, which are
called ‘deterministic effects’, are clinically observable in an individual
only if the radiation dose exceeds a certain threshold. Above this
threshold dose, a deterministic effect is more severe for a higher dose.
Managing Risk (Cont.…)
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8. IAEA
IAEA Basic Safety Standards
[GSR-Part 3 (Interim)]
The Basic Safety Standards (BSS) for Protecting
People and the Environment:
• aim to ensure the control of radiation exposure of
workers, medical patients, the public and the
environment and prevent the occurrence of short
term effects from high radiation doses and to
minimize the risk of long-term effects;
• apply internationally agreed standards;
• provide a practical guide to all involved in
radiation protection;
• are enforced in activities involving IAEA
assistance and support.
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9. IAEA
Types of Exposure Situations
• Planned exposure situations
situations involving the planned introduction and
operation of sources (including decommissioning,
disposal of radioactive waste, rehabilitation)
• Emergency exposure situations
unexpected situations such as those that may occur
during of a planned situation, or from a malicious act,
requiring urgent attention
• Existing exposure situations
situations that already exist when a decision on control
has to be taken, such as those by natural background
radiation and residues from past practices operated
outside the system
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10. IAEA
• Medical exposures of patients
incurred by patients as part of their own medical or
dental diagnosis or treatment; volunteers helping in
the support and comfort of patients; and biomedical
research volunteers
• Occupational exposures
exposure of workers incurred as a result of their work
(with the exception of excluded exposures and
exposures from exempt activities; medical exposure; and
background)
• Public exposures
all exposures of the public other than occupational
exposures and medical exposures of patients
Categories of Exposure
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11. IAEA
“The fundamental safety objective is to protect people and the
environment from harmful effects of ionizing radiation”.
This objective must be achieved without unduly limiting the
operation of facilities or the conduct of activities that give rise
to radiation risks. Therefore, the system of protection and
safety aims to assess, manage and control exposure to
radiation so that radiation risks, including risks of health effects
and risks to the environment, are reduced to the extent
reasonably achievable.
The System of Protection and Safety
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12. IAEA
• For planned exposure situations, each party with responsibilities for
protection and safety shall ensure, when relevant requirements apply to
that party, that no practice is undertaken unless it is justified.
• For emergency exposure situations and existing exposure situations,
each party with responsibilities for protection and safety shall ensure,
when relevant requirements apply to that party, that protective actions
or remedial actions are justified and are undertaken in such a way as to
achieve the objectives set out in a protection strategy.
• For all exposure situations, each party with responsibilities for
protection and safety shall ensure, when relevant requirements apply to
that party, that protection and safety is optimized.
Application of the Principles of Radiation Protection
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13. IAEA
• For planned exposure situations other than for medical
exposure, each party with responsibilities for protection
and safety shall ensure that, when relevant
requirements apply to that party, specified dose limits
are not exceeded.
• The application of the requirements for the system of
protection and safety shall be commensurate with the
radiation risks associated with the exposure situation.
Application of the Principles of Radiation
Protection (Cont.….)
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14. IAEA
• The government shall establish and maintain an appropriate and effective legal and
regulatory framework for protection and safety in all exposure situations. This
framework shall encompass both the assignment and the discharge of governmental
responsibilities, and the regulatory control of facilities and activities that give rise to
radiation risks. The framework shall allow for the fulfillment of international obligations.
• The government shall ensure that adequate arrangements are in place for the
protection of people and the environment, both now and in the future, against harmful
effects of ionizing radiation, without unduly limiting the operation of facilities or the
conduct of activities that give rise to radiation risks. This shall include arrangements
for the protection of people of present and future generations and populations remote
from present facilities and activities.
Responsibilities of the Government in
Implementing Safety
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15. IAEA
• The government shall ensure that the regulatory body is effectively
independent, in making decisions relating to protection and safety, of
persons and organizations using or promoting the use of radiation and
radioactive material, so that it is free from any undue influence by
interested parties and from any conflicts of interest, and that it has
functional separation from entities having responsibilities or interests
that could unduly influence its decision making.
Responsibilities of the Government in
Implementing Safety (Cont.…)
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16. IAEA
• The regulatory body shall establish requirements for the application of the
principles of radiation protection for all exposure situations and shall establish
or adopt regulations and guides for protection and safety.
• The regulatory body shall adopt a graded approach to the implementation of the
system of protection and safety, such that the application of regulatory
requirements is commensurate with the radiation risks associated with the
exposure situation.
• The regulatory body shall ensure the application of the requirements for
education, training, qualification and competence in protection and safety of all
persons engaged in activities relevant to protection and safety.
Responsibilities of the Regulatory Body in
Implementing Safety
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17. IAEA
The regulatory body shall establish a regulatory system for protection and safety
that includes :
(a) Notification and authorization;
(b) Review and assessment of facilities and activities;
(c) Inspection of facilities and activities;
(d) Enforcement of regulatory requirements;
(e) The regulatory functions relevant to emergency exposure situations and
existing exposure situations;
(f) Provision of information to, and consultation with, parties affected by its
decisions and, as appropriate, the public and other interested parties.
Responsibilities of the Regulatory Body in
Implementing Safety (Cont.…)
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18. IAEA
• The person or organization responsible for any facility or activity that
gives rise to radiation risks shall have the prime responsibility for
protection and safety, which cannot be delegated.
• The principal parties responsible for protection and safety are:
(a) Registrants or licensees, or the person or organization responsible for
facilities and activities for which notification only is required;
(b) Employers, in relation to occupational exposure;
(c) Radiological medical practitioners, in relation to medical exposure;
(d) Those persons or organizations designated to deal with emergency
exposure situations or existing exposure situations.
Responsibilities for Protection and Safety
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19. IAEA
Other parties shall have specified responsibilities in relation to protection
and safety. These other parties include:
(a) Suppliers of sources, providers of equipment and software, and
providers of consumer products;
(b) Radiation protection officers;
(c) Referring medical practitioners;
(d) Medical physicists;
(e) Medical radiation technologists;
(f) Qualified experts or any other party to whom a principal party has
assigned specific responsibilities;
(g) Workers other than workers listed in (a)–(f).
Responsibilities for Protection and Safety (Cont.…)
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20. IAEA
• The relevant principal parties and other parties having specified
responsibilities in relation to protection and safety shall ensure that all
personnel engaged in activities relevant to protection and safety have
appropriate education, training and qualification so that they understand
their responsibilities and can perform their duties competently, with
appropriate judgment and in accordance with procedures.
• The relevant principal parties shall permit access by authorized
representatives of the regulatory body to carry out inspections of their
facilities and activities and of their protection and safety records, and
shall cooperate in the conduct of inspections.
Responsibilities for Protection and Safety (Cont.…)
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21. IAEA
There are three main principles of
radiation protection;
Justification
Optimization of Protection
Dose limitation
103
The 2007 Recommendations of the
International Commission on Radiological
Protection
Principles of Radiation Protection
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22. IAEA
Any decision that alters the radiation
exposure situation should do more
good than harm.
It applies to all three exposure
situations
103
The 2007 Recommendations of the
International Commission on Radiological
Protection
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Justification

23. IAEA
• No practice or source within a practice should be
authorized unless the practice produces sufficient benefit
to the exposed individuals or to society to offset the
radiation harm that it might cause i.e. the practice should
be justified, taking into account social, economic and
other relevant factors.
• Applicants for authorization of a new practice must provide
sufficient evidence to the Regulatory Body of the benefits
versus harms of the intended use of radiation sources
Justification of a Practice
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24. IAEA
Justification of a Practice (Cont.…)
• The following practices are deemed to be not justified whenever
they would result in an increase, by the deliberate addition of
radioactive substances or by activation, in the activity of the
associated commodities or products:
a. practices involving food, beverages, cosmetics or any other
commodity or product intended for ingestion, inhalation or
percutaneous intake by, or application to, a human being; and
b. practices involving the frivolous use of radiation or radioactive
substances in commodities or products such as toys and
personal jewellery or adornments.
c. Human imaging using radiation used as a form of art or for
publicity purposes.
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25. IAEA
Principles of Optimization of Protection
Optimization requires the:
• magnitude of individual doses
• number of people exposed, and the
• likelihood of incurring exposures
to be kept As Low As Reasonably Achievable (the ALARA
principle).
It applies to all three exposures situations
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26. IAEA
Dose limitation
Dose limits should be set to ensure that no
individual faces an unacceptable risk in normal
circumstances.
Application of dose limits
The total dose to any individual from regulated
sources in planned exposure situations other than
medical exposure of patients should not exceed the
appropriate limits recommended by the
Commission
103
The 2007 Recommendations of the
International Commission on
Radiological Protection
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Dose limits

27. IAEA
Individual Dose Limits
Persons working with radiation (and members of the public
who live or work near to radiation sources and who might
receive avoidable and unnecessary radiation exposure) must
be protected to limit any unacceptable individual detriment.
This principle is achieved by prescribing individual dose limits
for occupational exposure and for members of the public.
The dose limits recommended in the IAEA GSR Part 3 are
intended to ensure a widely accepted level of safety
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28. IAEA
For potential hazards such as ionizing radiation, for which no
safe threshold can be assumed for stochastic effects, the
choice of dose limits cannot be based solely on health
considerations.
The definition and choice of dose limits necessarily involves
balancing health risks and social values.
However, it must be emphasized that the limits do not define
a dose limit below which there is no risk nor one which is
deemed dangerous or life threatening if exceeded.
Individual Dose Limits (Cont.…)
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29. IAEA
In summary, the prescribed dose limits:
• are not a demarcation line between “safe” and “dangerous”
exposures,
• are not necessarily the simplest and most effective tool in keeping
doses low and in ensuring the continuous improvement of the
practice;
• are not the sole measure of the effectiveness of a radiation
protection system.
Exceeding the prescribed dose limits does not necessarily mean that
there has been a breach of the national safety regulations.
Individual Dose Limits (Cont.…)
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30. IAEA
The principles of justification and optimization are
applicable to medical exposures, however, that of dose
limitation is not applicable to patients who receive radiation
exposure for the purposes of diagnosis or therapy.
Medical exposures should be justified (by the referring
medical practitioner) by weighing the expected diagnostic
or therapeutic benefits against the radiation detriment they
might cause. The benefits and risks of available alternative
techniques that do not involve radiation exposure also
should be taken into account.
Justification of Medical Practices
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31. IAEA
Any radiological examination for
occupational, legal or health insurance
purposes, undertaken without reference to
clinical indications, is not justified unless:
• it is expected to provide useful
information on the health of the individual
examined;
• or unless the specific type of
examination is justified by those
requesting it in consultation with relevant
professional bodies.
Justification of Medical Practices (Cont.…)
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32. IAEA
Mass screening of population groups involving medical
exposure (e.g. chest x-rays or mammography) is not justified
unless;
• the expected advantages for the individuals examined;
or
• for the population as a whole
are sufficient to compensate for the economic and social
costs, including the radiation detriment.
Justification of Medical Practices (Cont.…)
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33. IAEA
The exposure of humans for medical research is not justified
unless it is:
• in accordance with the provisions of the Helsinki
Declaration; and
• subject to the advice of an Ethical Review Committee
(or any other institutional body assigned similar
functions by national authorities) and to applicable
national and local regulations.
Justification of Medical Practices (Cont.…)
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34. IAEA
Radiological examinations for theft detection, detection of
concealed objects for criminal acts or for anti-smuggling
purposes are not justified but nevertheless be conducted, they;
• should not be considered medical exposure; and
• should be subject to the usual requirements set out in the
International Basic Safety Standards (GSR Part 3*).
Justification of Medical Practices (Cont.…)
*requirements of paras 3.61-3.67
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35. IAEA
A medical practitioner should be assigned the primary task and
obligation of ensuring overall patient protection and safety in
the prescription of, and during the delivery of, medical
exposure.
While individual dose limits do not apply to patients exposed
for the purposes of diagnosis or therapy, this responsibility
should include knowledge of patient doses and the
implementation of appropriate dose minimization measures.
Dose minimization in itself is not always a benefit and caution
must be taken to ensure that the desired outcomes of the
diagnosis or therapy are not compromised.
Optimisation of Medical Practices
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36. IAEA
Scope of the radiation protection system
The International Basic Safety Standards and other radiation
protection recommendations provide an appropriate
standard of protection for humans.
It is assumed that the standard of environmental control
needed to protect man to the degree currently thought
desirable will ensure that other species are not put at risk.
Occasionally, individual members of non-human species
might be harmed but not to the extent of endangering whole
species or creating imbalance between species.
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