IAEA Training Material on Radiation Protection in Radiotherapy

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IAEA Training Material on Radiation Protection in
Radiotherapy
Radiation Protection inRadiotherapy
Part 4 Principles of Radiation Protection Lecture
2 The BSS Framework
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The IAEA

• International Atomic Energy Agency
• Objective to seek to accelerate and enlarge the
  contribution of atomic energy to peace, health
  and prosperity throughout the world.
• Authorised to establish standards of safety for
  the protection of health and to provide for the
  application of these standards

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IAEA assembly
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The IAEA Basic Safety Standards

• International Basic Safety Standards for
  Protection against Ionizing Radiation and for the
  Safety of Radiation Sources, IAEA Safety Series
  No 115, Vienna 1996 (IAEA, FAO, ILO, OECD/NEA,
  PAHO and WHO)

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The Basic Safety Standards

• Sponsored by many international institutions
• A practical guide the BSS lays down basic
  principles and provides requirements for
  protection and safety
• To be filled by more specific information through
  guidelines and codes of practice

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Objectives of the lecture

• To become familiar with the terminology and
  requirements of the BSS
• To be able to apply the requirements of the BSS
  to the radiotherapy environment
• To appreciate the importance of an
  internationally harmonized set of safety
  standards, such as the BSS, for day to day
  radiotherapy practice

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Contents

• 1. Background and structure of the BSS
• 2. Some terminology
• 3. BSS requirements
• 4. The BSS Appendices and Schedules

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1. Historical Background

• First Basic Safety Standards 1962
• Revised Basic Safety Standards 1967
• Revised and Joint with FAO, ILO, OECD/NEA,
  WHO 1982
• ICRP published revised recommendations 1991
• Consultants, Senior experts meetings, ad hoc
  1991-1993
• working groups, technical committees
• 6th draft circulated to all member states Mar
  1994
• 7th Draft approved by IAEA Board of Governors
  Sept 1994
• Publication of Interim Version S.S.115I 1994
• Formal approval by co-sponsoring organizations
  1994-1996
• Publication of S.S.115 1996

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• Jointly sponsored by
• THE FOOD AND AGRICULTURE ORGANIZATION OF THE
  UNITED NATIONS
• THE INTERNATIONAL ATOMIC ENERGY AGENCY
• THE INTERNATIONAL LABOUR ORGANIZATION
• THE NUCLEAR ENERGY AGENCY OF THE OECD
• THE PAN AMERICAN HEALTH ORGANIZATION
• and
• THE WORLD HEALTH ORGANIZATION

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Hierarchy of IAEA documents
Safety Fundamentals
Safety Standards
Approved by IAEA Board of Governors
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Hierarchy of IAEA documents
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Objectives of the BSS

• The objective is to establish basic requirements
  for protection against the risks associated with
  exposure to ionizing radiation and for the safety
  of radiation sources that may deliver such
  exposure.
• The Standards have been developed from widely
  accepted radiation protection and safety
  principles, such as those published in the Annals
  of the ICRP and the IAEA Safety Series.

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LAYOUT of the BSS

• PREAMBLE Principles and Fundamental Objectives
• PRINCIPLE REQUIREMENTS
• General-responsibilities and organizational
• Practices
• Interventions
• APPENDICES DETAILED REQUIREMENTS
• Occupational exposure
• Medical exposure
• Public exposure
• Potential exposure safety of sources
• Emergency exposure situations
• Chronic exposure situations
• ANNEXES Numerical

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The Scope of the BSS

• The Standards comprise basic requirements to be
  fulfilled in all activities involving radiation
  exposure.
• The Standards lay down basic principles and
  indicate the different aspects that should be
  covered by an effective radiation protection
  programme.
• They are not intended to be applied as they stand
  in all countries and regions , but should be
  interpreted to take account of local situations,
  technical resources, the scale of installations
  and other factors.

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Applicability of the BSS

• The Standards apply to practices and
  interventions
• (a) carried out in a State that adopts the BSS
• (b) undertaken by States with assistance of FAO,
  IAEA, ILO, PAHO or WHO
• (c) carried out by IAEA or with materials,
  services, equipment and non-published information
  made available by the IAEA
• (d) where parties to bi/multi-lateral
  arrangements request application

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EXCLUSION

• Any exposure whose magnitude or likelihood is
  essentially unnamable to control, e.g.
• 40K in the body,
• cosmic radiation at earths surface
• and unmodified concentrations of radionuclides in
  most raw materials.

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EXEMPTION

• Practice or source may be exempted if
• effective dose lt 10mSv in a year
• collective effective dose committed by one year
  of practice lt 1manSv
• or
• exemption is the optimum option (using model
  scenarios derived nuclide-specific levels)

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GENERAL OBLIGATIONS

• Unless excluded or exempted (numerical criteria
  nuclide specific values) the standards apply -
  including requirements for
• notification
• registration
• licensing
• Each application for authorization requires a
  safety assessment.
• Each release of items from authorized premises
  requires clearance.

authorization
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2. BSS Some Terminology

• Definition of many terms is in
• IAEA publication Safety Fundamentals, Safety
  Series 120, 1996 and
• BSS glossary

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Authorization registration or licensing

• BSS 2.11. The Legal person responsible for any
  sealed source, unsealed source or radiation
  generator shall, unless the source is exempted,
  apply to the Regulatory Authority for an
  authorization which shall take the form of either
  a registration or a licence.

This applies to a radiotherapy department
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Authorization registration or licensing

• BSS 2.14. The legal person responsible for a
  source to be used for medical exposure shall
  include in the application for authorization
• (a) the qualifications in radiation protection
  of the medical practitioners who are to be so
  designated by name in the registration or
  licence or
• (b) a statement that only medical practitioners
  with the qualifications in radiation protection
  specified in the relevant regulations or to be
  specified in the registration or licence will be
  permitted to prescribe medical exposure by means
  of the authorized source.

This applies to radiotherapy
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Authorized legal persons registrants and
licensees

• BSS 2.15. Registrants and licensees shall bear
  the responsibility for setting up and
  implementing the technical and organizational
  measures that are needed for ensuring protection
  and safety for the sources for which they are
  authorized.
• They may appoint other people to carry out
  actions and tasks related to these
  responsibilities, but they shall retain the
  responsibility for the actions and tasks
  themselves.

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Quick question
Who is ultimately responsible for radiation
protection in your facility?
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Practice

• Any human activity that introduces or extends
  sources of exposure or exposure pathways.

Radiotherapy is a practice
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Practices can alter exposure
Dose
Additional dose attributable to the practice, D
E
Post-practice extant dose
Pre-practiceextant dose
Time
Introduction, operation and decommissioning of a
beneficial practice
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Intervention

• Any action intended to reduce or avert exposure
  or the likelihood of exposure to sources which
  are not part of a controlled practice or which
  are out of control.

Without intervention radiotherapy would result in
large exposures not only for the patient but also
for staff, visitors and general public
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Interventions
Averted dose by the intervention
Dose
Post-intervention dose
Pre-intervention dose
Time
Undertaking intervention
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National Infrastructure

• Enforcement of the Standards is the
  responsibility of national government. This
  requires a national infrastructure
• Legislation Regulations
• Regulatory Authority
• Trained personnel

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Regulatory Authority

• ESTABLISHED BY GOVERNMENT
• Given - Sufficient powers
• - Resources
• - Independence (effective)
• To - Receive Notifications
• - Carry out assessments
• - Issue Authorizations/Licenses
• - Inspect
• - Enforce

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3. The Principal Requirements of the BSS

• Specifies who are the responsible
• organizations and individuals, including the
  Regulatory Authority.
• Defines the administrative requirements,
  including licensing and registration.
• Uses the dose limitation system introduced in
  ICRP report 60.
• The detailed requirements are given in a number
  of Appendices and Schedules.

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Principal Requirements of the BSS

• A) Allocation of responsibility
• B) Administrative requirements
• C) Radiation protection requirements
• D) Management requirements
• E) Technical requirements
• F) Verification of Safety

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A) Allocation of responsibilities

• In radiotherapy
• Emergency Situations
• Occupational Exposure
• Medical Exposure
• Public Exposure
• Safety of Sources

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A) Allocation of responsibilities

• In radiotherapy
• Emergency Situations - part 13
• Occupational Exposure - part 8
• Medical Exposure - parts 9-12
• Public Exposure - part 17
• Safety of Sources - part 15

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Responsibilities for Occupational Exposure

• BSS Appendix I.1. Registrants and licensees and
  employers of workers who are engaged in
  activities involving normal exposures or
  potential exposure shall be responsible for
• (a) the protection of workers from occupational
  exposure and
• (b) compliance with any other relevant
  requirements of the Standards.

More details in part 8 of the course
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Responsibilities for Medical Exposure

• BSS Appendix II.1. Registrants and licensees
  shall ensure that
• (a) no patient be administered a diagnostic or
  therapeutic medical exposure unless the exposure
  is prescribed by a medical practitioner
• (d) for therapeutic uses of radiation, the
  calibration, dosimetry and quality assurance
  requirements of the Standards be conducted by or
  under the supervision of a qualified expert in
  radiotherapy physics

More details in parts 9 to 13 of the course
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Responsibilities for Public Exposure (BSS III.2 )

• III.1. Registrants and licensees shall apply the
  requirements of the Standards as specified by the
  Regulatory Authority to any public exposure
  delivered by a practice or source for which they
  are responsible, unless the exposure is excluded
  from the Standards or the practice or source
  delivering the exposure is exempted from the
  requirements of the Standards.

The BSS is applicable to radiotherapy - more
details in part 17 of the course
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B) Administrative requirements

• Notification
• Authorization (Registration/Licensing)
• as discussed before
• included are requirements for authorized legal
  persons BSS 2.15. Registrants and licensees
  shall bear the responsibility for setting up and
  implementing the technical and organizational
  measures that are needed for ensuring protection
  and safety for the sources for which they are
  authorized. They may appoint other people to
  carry out actions and tasks related to these
  responsibilities, but they shall retain the
  responsibility for the actions and tasks
  themselves. Registrants and licensees shall
  specifically identify the individuals responsible
  for ensuring compliance with the Standards.

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Notification

• BSS 2.10. Any legal person intending to carry
  out any of the actions specified under the
  General Obligations for practices of the
  Standards (see paras 2.7 and 2.8) shall submit a
  notification to the Regulatory Authority of such
  an intention 6. Notification for consumer
  products is required only with respect to
  manufacturing, assembling, importing and
  distributing.

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C) RADIATION PROTECTION REQUIREMENTS

• Justification of Practices
• positive net benefit
• Dose Limitation
• dose limits
• Optimization of Protection and Safety
• Constraints
• of various types
• guidance levels for medical exposure.

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Radiation protection requirements

• JUSTIFICATION OF PRACTICES
• Practices should not be authorized unless the
  benefits are greater than the detriments, taking
  account of social, economic and other factors

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Radiation protection requirements

• DOSE LIMITATION
• The normal exposure of individuals from
  authorized practices shall not exceed the dose
  limits specified in Schedule II of BSS

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Dose limits - BSS schedule II

• OCCUPATIONAL EXPOSURE
• II-5. The occupational exposure of any worker
  shall be so controlled that the following limits
  be not exceeded
• (a) an effective dose of 20 mSv per year
  averaged over five consecutive years
• (b) an effective dose of 50 mSv in any single
  year
• (c) an equivalent dose to the lens of the eye of
  150 mSv in a year and
• (d) an equivalent dose to the extremities (hands
  and feet) or the skin 39 of 500 mSv in a year.

More details in part 8 of the course
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Dose limits - BSS schedule II

• PUBLIC EXPOSURE
• II-8. The estimated average doses to the
  relevant critical groups of members of the public
  that are attributable to practices shall not
  exceed the following limits
• (a) an effective dose of 1 mSv in a year
• (b) in special circumstances, an effective dose
  of up to 5 mSv in a single year provided that the
  average dose over five consecutive years does not
  exceed 1 mSv per year
• (c) an equivalent dose to the lens of the eye of
  15 mSv in a year and
• (d) an equivalent dose to the skin of 50 mSv in
  a year.

More details in part 17 of the course
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Radiation protection requirements

• OPTIMIZATION OF PROTECTION AND SAFETY
• Doses to individuals, the number of persons and
  the likelihood of incurring exposures shall be
  kept as low as reasonably achievable, economic
  and social factors taken into account

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Radiation protection requirements

• DOSE CONSTRAINTS
• Optimization of protection and safety measures
  associated with a particular source within a
  practice shall be subject to dose constraints

Dose constraints are used prospectively e.g. at
the design stage of the facility
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D) MANAGEMENT REQUIREMENTS

• Safety Culture
• Quality Assurance
• Human Factors
• Qualified Experts

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Management requirements

• SAFETY CULTURE
• Purpose To encourage a questioning and learning
  attitude to protection and safety, whilst
  discouraging complacency. Policies and procedures
  should
• identify protection and safety as the highest
  priority
• Identify problems promptly
• Identify responsibilities of individuals
• define clear lines of authority (to the top)
• effect lines of communication

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Management requirements

• QUALITY ASSURANCE
• Establish QA programme to ensure
• that safety and protection requirements are
  satisfied
• the overall effectiveness of protection and
  safety is periodically reviewed
• this requires significant commitment from
  management (logistical and financial resources)

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Management requirements

• HUMAN FACTORS
• The contribution of human error to accidents
  should be minimized by
• training of personnel
• use of defined procedures
• use of ergonomic design to minimize operating
  errors
• use of safety systems

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Management requirements

• QUALIFIED EXPERTS
• Identify need and make available, for example
• Advice on radiation protection and safety
• Servicing and maintenance
• Calibration, clinical dosimetry...

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E) TECHNICAL REQUIREMENTS

• Security of Sources
• prevent theft, damage and unauthorized use
• keep under control at all times
• receiver must posses valid authorization
• carry out periodic inventory

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TECHNICAL REQUIREMENTS

• Defense in Depth
• use of physical or procedural layers of
  protection to prevent accidents or mitigate
  consequences
• built-in redundancy
• Good Engineering Practice
• equipment and facilities designed to
  (inter)national standards

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F) Verification of Safety

• Safety assessments
• Monitoring and
• verification
• of compliance
• Records

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Safety assessments

• BSS 2.37. Safety assessments related to
  protection and safety measures for sources within
  practices shall be made at different stages,
  including siting, design, manufacture,
  construction, assembly, commissioning, operation,
  maintenance and decommissioning, as appropriate,
  in order
• (a) to identify the ways in which normal
  exposures and potential exposures could be
  incurred, account being taken of the effect of
  events external to the sources as well as events
  directly involving the sources and their
  associated equipment
• (b) to determine the expected magnitudes of
  normal exposures and, to the extent reasonable
  and practicable, to estimate the probabilities
  and the magnitudes of potential exposures and
• (c) to assess the quality and extent of the
  protection and safety provisions.

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Monitoring and verification of compliance

• BSS 2.38. Monitoring and measurements shall be
  conducted of the parameters necessary for
  verification of compliance with the requirements
  of the Standards.
• BSS 2.39. For the purposes of monitoring and
  verification of compliance, suitable equipment
  shall be provided and verification procedures
  introduced. The equipment shall be properly
  maintained and tested and shall be calibrated at
  appropriate intervals with reference to standards
  traceable to national or international
  standards.

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Records

• BSS 2.40. Records shall be maintained of the
  results of monitoring and verification of
  compliance, including records of the tests and
  calibration carried out in accordance with the
  Standards.

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4. Appendices and Schedules of the BSS

• Detailed Requirements
• Provide specific guidelines for practices
• Followed by schedules which provide the
  numerical database for application of the
  standards

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The Appendices to the BSS

• I Occupational Exposure
• II Medical Exposure
• III Public Exposure
• IV Potential Exposure Safety of Sources
• V Emergency Exposure Situations
• VI Chronic Exposure Situations

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EXPOSURES
most important for radiotherapy are

• Occupational exposure
• Medical exposure
• Public exposure

• Appendix I (Part 8 of the course)
• Appendix II (Parts 9 to 13)
• Appendix III (Parts 16 and 17)

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Exposures continued

• Potential exposure - safety of sources
• Emergency exposure
• Chronic exposure

• Appendix IV (covered in parts 14 and 15 of the
  course)
• Appendix V (Part 13)
• Appendix VI (not relevant for present course)

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Schedules

• I Exemptions
• II Dose limits
• III Guidance levels for medical exposure
• IV Dose level for interventions
• V Intervention and action levels for emergency
  exposure situations
• VI Action levels for chronic exposure

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Exemption criteria for practices

• The additional individual dose attributable to
  the exempted practice should be of the order of
  10 uSv or less in a year
• Either the collective dose committed by a year of
  practice should be lower than 1 man sievert,
  orexemption should be the optimum option.

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mSv per year
Summary of limits and constraints
DOSE LIMIT
1
0.3
DOSE CONSTRAINT
OPTIMISATION
0.1
ADDED ANNUAL DOSEFROM PRACTICES
EXEMPTION
0.01
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mSv in a year
Summary of action and intervention levels
1,000 300 100 30 10
3 1
INTERVENTION ALMOST ALWAYS REQUIRED
INTERVENTION MAY BE REQUIRED
INDIVIDUALS EXTANT ANNUAL DOSE
INTERVENTION USUALLY NOT REQUIRED
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Any questions?
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Question
Please discuss the differences between license
and registration as given in the BSS
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License

• BSS glossary An authorization granted by the
  Regulatory Authority on the basis of a safety
  assessment and accompanied by specific
  requirements and conditions to be complied with
  by the licensee.

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Registration

• BSS glossary A form of authorization for
  practices of low or moderate risks whereby the
  legal person responsible for the practice has, as
  appropriate, prepared and submitted a safety
  assessment of the facilities and equipment to the
  Regulatory Authority. The practice or use is
  authorized with conditions or limitations as
  appropriate. The requirements for safety
  assessment and the conditions or limitations
  applied to the practice should be less severe
  than those for licensing.

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Registration and license...

• Both are authorizations by the Regulatory
  Authority of a certain practice by a user.
  Radiotherapy requires a license!

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Acknowledgments

• Lee Collins, Westmead Hospital, Sydney
• Pedro Ortiz, IAEA