Presentation on theme: "Fundamental Principles of Radiation Protection"— Presentation transcript:
1Fundamental Principles of Radiation Protection Day 3 – Lecture 6requirements of paras
2ObjectiveTo review the fundamental principles of protection recommended in the international Basic Safety Standards, General Safety Requirements Part 3 (IAEA GSR Part 3).requirements of paras
3Radiation Protection Fundamentals 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.*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 sourcesso as to increase the exposure or the likelihood of exposure of people or the number of people exposed.requirements of paras
4Radiation Protection Fundamentals 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; andto ensure that all reasonable steps are taken to minimize the risk of stochastic effects (e.g. probability of cancer induction and of hereditary effects).requirements of paras
5Managing RiskIn 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.requirements of paras
6Managing Risk (Cont.…)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.requirements of paras
7Managing Risk (Cont.…)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.
8IAEA 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.requirements of paras
9Types of Exposure Situations Planned exposure situationssituations involving the planned introduction and operation of sources (including decommissioning, disposal of radioactive waste, rehabilitation)Emergency exposure situationsunexpected situations such as those that may occur during of a planned situation, or from a malicious act, requiring urgent attentionExisting exposure situationssituations 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
10Categories of Exposure Occupational exposuresexposure 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 exposuresall exposures of the public other than occupational exposures and medical exposures of patientsMedical exposures of patientsincurred 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
11The System of Protection and Safety “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.requirements of paras
12Application of the Principles of Radiation Protection 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.
13Application of the Principles of Radiation Protection (Cont.….)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.
14Responsibilities of the Government in Implementing Safety 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.
15Responsibilities of the Government in Implementing Safety (Cont.…) 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.
16Responsibilities of the Regulatory Body in Implementing Safety 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.requirements of paras
17Responsibilities of the Regulatory Body in Implementing Safety (Cont 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.
18Responsibilities for Protection and Safety 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.
19Responsibilities for Protection and Safety (Cont.…) 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).
20Responsibilities for Protection and Safety (Cont.…) 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.
21Principles of Radiation Protection There are three main principles of radiation protection;JustificationOptimization of ProtectionDose limitation103The 2007 Recommendations of the International Commission on Radiological Protectionrequirements of paras
22Justification103The 2007 Recommendations of the International Commission on Radiological ProtectionAny decision that alters the radiation exposure situation should do more good than harm.It applies to all three exposure situations
23Justification of a Practice 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 sourcesrequirements of paras
24Justification 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: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; andpractices involving the frivolous use of radiation or radioactive substances in commodities or products such as toys and personal jewellery or adornments.Human imaging using radiation used as a form of art or for publicity purposes.requirements of paras
25Principles of Optimization of Protection Optimization requires the:magnitude of individual dosesnumber of people exposed, and thelikelihood of incurring exposuresto be kept As Low As Reasonably Achievable (the ALARA principle).It applies to all three exposures situationsrequirements of paras
26Dose limits Dose limitation Application of dose limits Dose limits should be set to ensure that no individual faces an unacceptable risk in normal circumstances.Application of dose limitsThe 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 Commission103The 2007 Recommendations of the International Commission on Radiological Protection
27Individual 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 safetyrequirements of paras
28Individual Dose Limits (Cont.…) 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.requirements of paras
29Individual Dose Limits (Cont.…) 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.requirements of paras
30Justification of Medical Practices 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.requirements of paras
31Justification of Medical Practices (Cont.…) 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.requirements of paras
32Justification of Medical Practices (Cont.…) 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; orfor the population as a wholeare sufficient to compensate for the economic and social costs, including the radiation detriment.requirements of paras
33Justification of Medical Practices (Cont.…) The exposure of humans for medical research is not justified unless it is:in accordance with the provisions of the Helsinki Declaration; andsubject 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.requirements of paras
34Justification of Medical Practices (Cont.…) 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; andshould be subject to the usual requirements set out in the International Basic Safety Standards (GSR Part 3*).*requirements of parasrequirements of paras
35Optimisation of Medical Practices 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.requirements of paras
36Scope 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.requirements of paras