Radiation Protection in Radiotherapy

1
Radiation Protection inRadiotherapy
IAEA Training Material on Radiation Protection in
Radiotherapy

• Part 12
• Quality Assurance

2
QUALITY as a goal

• The totality of features or characteristics that
  bear on our ability to satisfy the stated or
  implied goal of effective patient care.
• Comprehensive QA for Radiation Oncology,
• AAPM Task Group 40, 1994
• To ensure the goal is reached requires a fully
  implemented Quality Assurance program throughout
  the facility.

3
What is Quality Assurance?

• All those planned and systematic actions
  necessary to provide confidence that a product or
  service will satisfy given requirements for
  quality.
• ISO 9000

4
Quality Assurance

• In the BSS seen in the context of medical
  exposure as essential for radiation protection of
  the patient
• Quality Assurance and Control is also important
  to assess the overall effectiveness of protection
  and safety measures

5
Objectives

• To be familiar with the concepts of Quality
  Assurance as a multidisciplinary activity and its
  interrelation with radiation protection in
  radiotherapy.
• To be familiar with Quality Assurance procedures
  as a tool for reviewing and assessing the overall
  effectiveness of a radiation protection program.
• To be able to understand the need for and role of
  specific tests in the context of Quality Control
  and be able to identify appropriate national and
  international protocols for this task
• To be aware of the need for involvement of
  professionals in a Quality Assurance program and
  for radiation protection

6
Contents

• 1. Quality Assurance and the BSS
• 2. QA systems
• 3. Quality Control in radiotherapy
• External Beam RT
• Brachytherapy
• 4. QA and radiation protection

7
1. Quality Assurance and the BSS (Managerial
Requirements)

• BSS 2.29. Quality assurance programmes shall be
  established that provide, as appropriate
• (a) adequate assurance that the specified
  requirements relating to protection and safety
  are satisfied and
• (b) quality control mechanisms and procedures for
  reviewing and assessing the overall effectiveness
  of protection and safety measures.

8
QA and QC

• Quality Assurance is the overall process which is
  supported by Quality Control activities
• Quality Control describes the actual mechanisms
  and procedures by which one can assure quality

9
Quality Assurance and Medical Exposure

• BSS appendix II.22. Registrants and licensees,
  in addition to applying the relevant requirements
  for quality assurance specified elsewhere in the
  Standards, shall establish a comprehensive
  quality assurance programme for medical exposures
  with the participation of appropriate qualified
  experts in the relevant fields, such as
  radiophysics or radiopharmacy, taking into
  account the principles established by the WHO and
  the PAHO.

You must establish a QA program!
10
Relevant for radiotherapy

• WORLD HEALTH ORGANIZATION, Quality Assurance in
  Radiotherapy, WHO, Geneva (1988).
• PAN AMERICAN HEALTH ORGANIZATION, Publicación
  Cientifica No. 499, Control de Calidad en
  Radioterapia Aspectos Clínicos y Físicos, PAHO,
  Washington, DC (1986).

11
BSS appendix II.23

• Quality assurance programmes for medical
  exposures shall include
• (a) measurements of the physical parameters of
  the radiation generators, imaging devices and
  irradiation installations at the time of
  commissioning and periodically thereafter
• (b) verification of the appropriate physical and
  clinical factors used in patient diagnosis or
  treatment

Check machine and data!
12
Consequences for radiotherapy

• A good acceptance testing and commissioning
  program is fundamental for any QA activities
• QA activities are typically a subset of the tests
  and procedures used for the commissioning of a
  unit
• QA applies to both physical and clinical aspects
  of the treatment

13
BSS appendix II.23

• Quality assurance programmes for medical
  exposures shall include
• ...
• (c) written records of relevant procedures and
  results
• (d) verification of the appropriate calibration
  and conditions of operation of dosimetry and
  monitoring equipment .

14
Consequences for radiotherapy

• Treatment records must be kept of all relevant
  aspects of the treatment - including
• Session and Summary Record information
• Records all treatment parameters
• Dose Calculations
• Dose Measurements
• Particular emphasis is placed on QA of dosimetry

15
Treatment records

• Must contain all relevant information
• Can be in electronic format

16
BSS appendix II.23

• Quality assurance programmes for medical
  exposures shall include
• ...
• and
• (e) as far as possible, regular and independent
  quality audit reviews of the quality assurance
  programme for radiotherapy procedures

17
Consequences for radiotherapy

• A QA system itself and its outcomes must be
  critically reviewed
• External audits are recommended to verify that
  the checks are not only done but that they also
  achieve what they are supposed to do
• Every good system requires an independent look at
  times

18
2. QA systems

• Many QA systems exist - one important example is
  the ISO 9000 system
• They are highly successful in manufacturing
  industry because they do improve productivity and
  avoid costly mistakes

19
Good QA systems in radiotherapy

• Improves work practices
• Would have prevented most of the major accidents

20
ISO 9000

• Comprehensive set of standards for QA (mainly in
  manufacturing and service industry)
• Adapted e.g. by ESTRO to the radiotherapy
  environment
• European Society for Therapeutic Radiology and
  Oncology (ESTRO) Advisory Report to the
  Commission of the European Union for the 'Europe
  Against Cancer Programme'. Quality Assurance in
  radiotherapy. Radiother. Oncol. 35 61-73 1995.

21
Quick note aside How to get ISO 9000 certified
implementation steps

• Application
• Preliminary
• Pre-audit
• System audit
• Certification - registration
• Surveillance audits

22
A Comprehensive Quality Assurance Program

• The details of such a program are often wrapped
  up in a Code of Practice.
• Quality Assurance in Radiotherapy, ESTRO
  Advisory Report, 1995
• Comprehensive QA for Radiation Oncology Report
  of AAPM Radiation Therapy Committee Task Group
  40, 1994
• Quality Assurance in Radiotherapy, WHO, 1988

23
A Comprehensive QA Program typically comprises

• Quality Assurance Committee
• Policies and Procedures Manual
• Quality Assurance team
• Quality audit
• Resources

24
QA Committee Membership

• Must represent the many disciplines within the
  department
• Should be chaired by the Head of Department
• As a minimum must include a medical doctor, a
  physicist, a radiotherapy technologist and an
  engineer responsible for service and maintenance
• Must be appointed and supported by senior
  management
• Must have sufficient depth of experience to
  understand the implications of the process
• Must have the authority and access to the
  resources to instigate and carry out the QA
  process

25
Quality Assurance Committee

• Should represent the department
• Should be visible AND accessible to staff
• Oversees the entire Quality Assurance program
• Writes policies to ensure the quality of patient
  care
• Assists staff in tailoring the program to meet
  the needs of the Department (using published
  reports as a guide)
• Monitor and audit the program to ensure that each
  component is being performed and documented

26
Quality Assurance Committee

• Set agreed Action Levels
• Example Physics is given the authority to ensure
  correct accelerator output
• For the daily output check two Action Levels
  are set
• For any daily measurement which exceeds 2 but
  less than 4, treatment may continue but the
  Senior Physicist responsible must be notified
  (immediately)
• For any daily measurement which exceed 4,
  treatment must STOP immediately and the problem
  investigated by the Senior Physicist responsible

27
Action levels

• Are quantitative
• Reflect the required outcome
• Are informed by the achievable outcome
• Must be unambiguous
• Should be easy to understand

28
QA Committee review

• Where Action Levels have been exceeded
• Where set procedures have been discovered to be
  faulty
• After a review, recommendations must be
  formulated in writing for improving the QA
  program
• When errors are discovered the fault often lies
  in the process rather than in the action of
  individuals

29
Documentation for the Quality Assurance Committee

• Terms of Reference
• The Committee must meet at established intervals
  and retain for audit purposes the minutes of its
  meetings, actions recommended and the results
  attained.
• In short, there is a QA program for the QA
  Committee

30
Policies and Procedures Manual

• This manual contains clear and concise statements
  of all the policies and procedures carried out in
  the Department
• Reviewed (typically) yearly
• Updated as procedures change

Policies and Procedures Manual
31
Policies and Procedures Manual

• As a minimum, sections should exist for
• Administrative procedures
• Clinical procedures
• Treatment procedures
• Physics procedures
• Radiation safety

32
Policies and Procedures Manual

• It must be signed off by the Head of Department
  and appropriate section heads
• It is important that all staff have ownership
  to the manual - it should reflect the opinions of
  all and be agreed to by all
• A list of all copies of the Manual and their
  locations must be kept to ensure that each copy
  is updated

33
Quality Assurance Team

• Includes all disciplines
• Well defined responsibility and reporting
  structure
• Each member of the team must
• Know his/her responsibility
• Be trained to perform them
• Know what actions are to be taken should a test
  or action be outside the preset action levels

34
Responsibility Chart
Leer
Professional
Area
35
Quality Assurance Team

• Each member of the team must also
• Have at least some understanding of the
  consequences when tests or actions are outside
  the action levels
• Maintain records documenting the frequency of
  performance, the results and the corrective
  action taken if necessary

36
Quality Audit

• A systematic and independent examination and
  evaluation to determine whether quality
  activities and results comply with planned
  arrangements and whether the arrangements are
  implemented effectively and are suitable to
  achieve the objectives.
• Quality assurance in radiotherapy., Radiother.
  Oncol., 1995

Do you do what you say you do?
37
Quality Audit

• Ideally performed by someone outside of the
  organisation
• Examples
• IAEA/WHO TLD program for check of dose in therapy
  units
• EQUAL program in Europe
• Audits of clinical trials participation

38
Quality Assurance does not stop here!

• The Quality Assurance Committee and the Quality
  Assurance team must continuously monitor new
  information and implement this in their procedures

39
Continuous Quality Improvement

• CQI - many other acronyms are available for this
• Part of virtually all QA systems
• Improved methods on cancer patient management are
  documented in clinical trial reports.
• Quality assurance protocols are continuously
  under development in many countries
• Regular Quality Assurance meeting for all members
  of a Section
• Continuing education - lectures, workshops,
  journal clubs and must be available for all staff

40
And finally QA is not a threat, it is an
opportunity

• It is essential in a QA program that all staff
  feel free to report errors
• A non threatening environment must exist
• Reward honesty with encouragement
• Education is the key, not punishment

41
3. Quality Control in radiotherapy

• Many documents exist that specify what QC
  activities should be performed in radiotherapy

42
QC should ensure every step in the treatment
chain...
e.g. check source activity
e.g. hand calculation of treatment time
43
Radiother. Oncol. 1992 gt 50 occasions of data
transfer from one point to another for each
patient! If one of them is wrong - the overall
outcome is affected
44
QC activities in radiotherapy

• Three general areas
• Physical dosimetry
• Treatment planning (dealt with part 10 lecture 3C
  of the course)
• Patient treatment

45
QC activities

• Must be planned prospectively
• daily
• weekly
• monthly
• annually
• whenever needed
• The following is only a suggestion!

46
A collection of forms

• Constantinou C. Protocol and procedures for
  quality assurance of linear accelerators.
  Brockton Constantinou 1994. Available from
  Medical Physics Publishing, Madison.

47
External Beam RadiotherapyExamples for daily QC

• Safety
• door and other interlocks
• radiation warning lights
• audiovisual
• radiation area monitor
• Radiation constancy check
• Mechanical/optical pointers

PTW Linacheck
48
Test of optical components

• Used for patient set-up
• Essential
• Easy to perform
• Jigs available

RMI test tool
49
Alignment of lasers for patient set-up

• Should point to the isocentre
• Check also line width
• Check line alignment at least 20cm beyond
  isocentre

Gammex laser and test tool
50
Quality Control - Weekly

• Check of source positioning (cobalt 60)
• Couch movements (lateral, vertical, longitudinal)

51
Example for weekly QC summary

• From Constantinou 1992

52
Quality Control - Monthly

• Dosimetry
• Output constancy
• Backup monitors
• Central axis DD constancy
• Flatness/symmetry constancy
• Timer end effect

53
Quality Control - Monthly

• Safety interlocks
• emergency
• wedge etc
• Light/ radiation field coincidence
• Scales
• Isocentre position
• Cross hair position

PTW
54
Quality Control - Monthly
RMI

• Field size indicators
• Distance measuring indicators
• Jaw symmetry
• Latching of wedges, trays etc.
• Wedge position (factors etc.)

55
Quality Control - Annual

• Dosimetry
• Safety
• MechanicalThese checks are a scaled down
  version of the commissioning checks. It is a
  major QC exercise and is intended to validate the
  unit for another twelve months.

56
How to decide on frequency for tests?

• Likelihood of failure
• Severity of the consequences if something goes
  wrong
• Ease of the test - resources required
• This depends on local circumstances!!!

57
Time requirements for QC

• External beam per megavoltage unit
• daily 30 minutes
• weekly 2 hours
• monthly gt 4 hours
• annual 2 days
• These are estimates only - a qualified expert
  must decide on the actual requirements for a
  particular treatment unit

Siemens Primus Linac
58
QC for Brachytherapy Sources

• The following QC should be done on receipt of the
  sources and documented
• Physical/chemical form
• Source encapsulation
• Radionuclide distribution and uniformity
• Autoradiograph
• Uniformity of activity amongst seeds
• Visual inspection of seeds in ribbons

Mentor
59
QC for Brachytherapy Sources

• Calibration
• Do on receipt and document
• Ideal - every source
• Long half-life sources (e.g. Cs 137)
• All
• Short half-life sources (e.g. I 125)
• If only a few, do them all
• If a large number, do a sample e.g. 10

Nucletron
60
QC for Brachytherapy Sources- multiple seeds

• Suggested calibration tolerances
• Ideal
• mean of batch (3)
• Deviation from mean (5)
• Practical
• Review manufacturers documentation for
  tolerances
• Review ALL the manufacturers documentation

61
QC for Remote Afterloading

• Before each treatment day
• Room safety door interlocks
• Lights and alarms
• Radiation monitor
• Console functions
• Visual inspection of source guides
• Verify accuracy of ribbon preparation

Gammasonics
62
QC for Remote Afterloading

• Weekly
• Accuracy of source and dummy loading
• Source positioning
• At each source change or quarterly
• Calibration
• Timer function
• Accuracy of source guides and connectors

63
QC for Remote Afterloading

• Annual
• Dose calculation algorithm
• Simulate emergency conditions
• Verify source inventory

64
QC Documentation

• Forms shall be established to guide the process
• easy to follow (even late in the evening after
  normal treatment has finished)
• diagrams useful

65
Examples for forms
66
Forms are useful for all tests
Simple ticks may be sufficient
Empty space for comments and drawings
67
Special equipment and procedures

• All equipment and all procedures should be tested
• To design a QC protocol, one needs to fully
  understand the goals and all steps of the
  procedure
• Requires a qualified expert
• Action levels should be set

68
A note on action levels

• Not too tight - one must be realistic about what
  can be achieved
• Not too lax - one must identify unsatisfactory
  practice
• As the practice improves, the action levels may
  be tightened

69
Not only treatment units require QC Simulator

• Appropriate sections from the QC activities for a
  treatment unit
• kVp and mAs calibration
• Image intensifier quality checks
• Automatic exposure control if applicable
• Film processor

70
CT scanner

• Image quality
• Scaling and deformation
• Transfer of data
• Transfer of patient (is positioning OK, is couch
  on CT and linac identical?)

Gammex RMI CT test tool
71
QC for Dosimetry Equipment

• Local standard
• 2 yearly calibration
• Field instruments
• yearly calibration
• Linearity
• Leakage
• Recombination

PTW
72
QC for Measuring Equipment

• Automated scanners
• Positional accuracy
• Alignment
• Accuracy of data analysis
• Accessories
• Thermometer
• Barometer

73
Clinical QC

• Not only physics and dosimetry must be subject to
  QC, also clinical management
• A good way to do this are chart rounds

74
Chart Rounds

• Regular review of patients
• Can be all patients or randomly selected patients
• Should include all patients with unexpected
  severe complications

75
Treatment Verification - do not check individual
links in the chain but verify the overall outcome
Treatment verification
76
Treatment Verification

• Checks large parts of the treatment chain at once
  one detects if something is wrong but not
  necessarily what the problem is.
• Good strategy when things are mostly OK and
  within tight tolerances
• Allows to follow complex processes

77
Example for verificationWHO/IAEA photon dose
intercomparison
TLD capsules
Level 1 Intercomparison Dose in Reference
Conditions
78
Treatment verification

• May be suitable for external audits
• Should verify localization of the radiation beam
  AND the dose delivered
• Could include in vivo dosimetry

79
4. QA and radiation protection

• Quality assurance is essential for a functioning
  system of radiation protection
• The BSS identifies the following areas in
  particular
• Requirements for Practices
• Safety of Sources
• Medical Exposure
• Occupational Exposures

80
QA in medical exposures

• Physical QA as discussed before
• Process QA

Leer
81
QA Program Arrangements to be required from the
licensee

• Procedures to establish patient identity
• Procedures to ensure accordance with prescription
  by a medical practitioner
• Procedures to ensure that radiation sources,
  including equipment can only be purchased from
  manufacturers and distributors authorized by the
  Regulatory Authority

82
Also the radiation protection program itself
requires QA

• Check that the program meets its objectives
• Document improvements
• Document and rectify deficiencies
• Raise awareness

83
The cost of QA

• Dedicated staff - qualifications, training and
  numbers
• Equipment - include allowance for redundancy
• Time - commissioning, QA, reports, meetings,
  training

84
What do we get?
Yes, correct - lots of documentation. But there
are other benefits...
85
The benefits of QA

• Benefits for the department
• improved management system
• improved communication
• improved safety
• less duplication and waste
• Benefits to patients
• optimized procedure
• re-assurance

86
Additional benefits

• Credibility
• Potential to attract funding (and account for
  it)
• Participation in multicenter clinical trials
• Regular updates and audits to continue the
  improvements
• Pride and confidence of staff

87
Involvement of Administration

• Without the support of the Administration the
  financial resources will not be made available
• The AAPM considers this to be so important that
  in their Quality Assurance policy they make the
  very first section Part A Information for
  Radiation Oncology Administrators.
• Educate those who control funding
• Comprehensive QA for Radiation Oncology, Task
  Group 40, 1994

88
But - Beware the Administration Tick in the Box
syndrome!

• Administration will agree with QA
• They may even insist upon it
• Without education they will not understand what
  that really means in our environment
• Most administrators equate QA with an audit
• Many simply require the right boxes get ticked so
  they can be seen to do have done their job - this
  is not enough...

89
What do we risk without a Quality Assurance
Program?

• Exeter, UK
• New cobalt 60 source installed
• Over the next 5 months, 207 patients were
  overdosed by 25 due to an incorrect calibration
• Contributing factors
• Calibration details not recorded
• Little documentation or protocols

90
What do we risk without a Quality Assurance
Program?

• Exeter Contributing factors (cont.)
• Reduced staffing levels (money)
• No independent check of calculations
• No independent check calibration
• It was detected during a Nation wide survey!

91
Where to get more information

• AAPM task group 40 Kutcher GJ, Coia L, Gillin M,
  Hanson W, Leibel S, Morton RJ, Palta J, Purdy J,
  Reinstein L, Svensson G, et al. Comprehensive QA
  for radiation oncology report of AAPM therapy
  committee task group 40. Med Phys
  199421581-618.
• AAPM task group 53 Fraas, B. et al. Quality
  assurance for clinical radiotherapy treatment
  planning. Med. Phys. 25 1773-1829 1997.
• AAPM task group 56 Nath R. Anderson L. Meli
  J. Olch A. Stitt J. A. Williamson J. Code of
  practice for brachytherapy physics report of the
  AAPM Radiation Therapy Committee Task Group No
  56. Med. Phys. 241558-98 1997.
• ACPSEM Position Paper Millar M, Cramb J, Das R,
  Ackerly T, Brown G, Webb D. ACPSEM Position
  Paper Recommendations for the safe use of
  external beams and sealed brachytherapy sources
  in radiation oncology. Aust.Phys.Eng.Sci.Med.
  1997 20 (Supp) 1-35
• Institute of Physical Sciences in Medicine.
  Commissioning and quality assurance of linear
  accelerators, IPSM report 54. York IPSM 1988.
• International Standards Organisation. Quality
  management and quality assurance standards. ISO
  9000 series.
• PAN AMERICAN HEALTH ORGANIZATION, Publicación
  Cientifica No. 499, Control de Calidad en
  Radioterapia Aspectos Clínicos y Físicos, PAHO,
  Washington, DC (1986).

92
WHO (World Health Organisation). Quality
Assurance in radiotherapy. Geneva 1988.
93
Summary

• Quality Assurance is an essential part of
  radiotherapy
• It affects all aspects including the radiation
  protection program
• There are many different standards and guidelines
  for specific QA activities - it requires a
  qualified expert to choose the most appropriate
  for a particular center
• QA requires and encourages regular external
  audits
• QA is a continuous process - it is aimed at
  achieving improvements not laying blame.

94
Any questions?
95
Question

• Please give an example for the concept of
  Continuous Quality Improvement from your practice.

96
Example just one of many

• A centre intends to improve treatment set-up. The
  measure patient positioning using port films on
  20 patients e.g. of the prostate. The random
  variations are of the order of 8mm and the
  systematic error on average 9mm.
• The systematic error could at least partially
  attributed to different couch sag in simulator
  and treatment unit. This is reflected in update
  of the procedures.
• A repeat test shows that not only the systematic
  but also the random uncertainty have improved
  (the latter potentially because of heightened
  awareness). The smaller random variation allows
  to pick up other systematic errors
• In addition to this the positive experience leads
  to the same tests to be done for other treatment
  sites...

97
Acknowledgment

• Lee Collins, Westmead Hospital, Sydney
• Lyn Oliver, Royal North Shore Hospital, Sydney