Title: Radiation Protection in Radiotherapy
1Radiation Protection inRadiotherapy
IAEA Training Material on Radiation Protection in
Radiotherapy
- Part 12
- Quality Assurance
2QUALITY 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.
3What 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
4Quality 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
5Objectives
- 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
6Contents
- 1. Quality Assurance and the BSS
- 2. QA systems
- 3. Quality Control in radiotherapy
- External Beam RT
- Brachytherapy
- 4. QA and radiation protection
71. 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.
8QA 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
9Quality 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!
10Relevant 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 ClÃnicos y FÃsicos, PAHO,
Washington, DC (1986).
11BSS 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!
12Consequences 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
13BSS 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 .
14Consequences 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
15Treatment records
- Must contain all relevant information
- Can be in electronic format
16BSS 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
17Consequences 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
182. 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
19Good QA systems in radiotherapy
- Improves work practices
- Would have prevented most of the major accidents
20ISO 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.
21Quick note aside How to get ISO 9000 certified
implementation steps
- Application
- Preliminary
- Pre-audit
- System audit
- Certification - registration
- Surveillance audits
22A 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
23A Comprehensive QA Program typically comprises
- Quality Assurance Committee
- Policies and Procedures Manual
- Quality Assurance team
- Quality audit
- Resources
24QA 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
25Quality 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
26Quality 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
27Action levels
- Are quantitative
- Reflect the required outcome
- Are informed by the achievable outcome
- Must be unambiguous
- Should be easy to understand
28QA 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
29Documentation 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
30Policies 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
31Policies and Procedures Manual
- As a minimum, sections should exist for
- Administrative procedures
- Clinical procedures
- Treatment procedures
- Physics procedures
- Radiation safety
32Policies 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
33Quality 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
34Responsibility Chart
Leer
Professional
Area
35Quality 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
36Quality 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?
37Quality 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
38Quality 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
39Continuous 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
40And 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
413. Quality Control in radiotherapy
- Many documents exist that specify what QC
activities should be performed in radiotherapy
42QC should ensure every step in the treatment
chain...
e.g. check source activity
e.g. hand calculation of treatment time
43Radiother. 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
44QC activities in radiotherapy
- Three general areas
- Physical dosimetry
- Treatment planning (dealt with part 10 lecture 3C
of the course) - Patient treatment
45QC activities
- Must be planned prospectively
- daily
- weekly
- monthly
- annually
- whenever needed
- The following is only a suggestion!
46A collection of forms
- Constantinou C. Protocol and procedures for
quality assurance of linear accelerators.
Brockton Constantinou 1994. Available from
Medical Physics Publishing, Madison.
47External 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
48Test of optical components
- Used for patient set-up
- Essential
- Easy to perform
- Jigs available
RMI test tool
49Alignment 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
50Quality Control - Weekly
- Check of source positioning (cobalt 60)
- Couch movements (lateral, vertical, longitudinal)
51Example for weekly QC summary
52Quality Control - Monthly
- Dosimetry
- Output constancy
- Backup monitors
- Central axis DD constancy
- Flatness/symmetry constancy
- Timer end effect
53Quality Control - Monthly
- Safety interlocks
- emergency
- wedge etc
- Light/ radiation field coincidence
- Scales
- Isocentre position
- Cross hair position
PTW
54Quality Control - Monthly
RMI
- Field size indicators
- Distance measuring indicators
- Jaw symmetry
- Latching of wedges, trays etc.
- Wedge position (factors etc.)
55Quality 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.
56How 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!!!
57Time 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
58QC 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
59QC 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
60QC 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
61QC 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
62QC 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
63QC for Remote Afterloading
- Annual
- Dose calculation algorithm
- Simulate emergency conditions
- Verify source inventory
64QC Documentation
- Forms shall be established to guide the process
- easy to follow (even late in the evening after
normal treatment has finished) - diagrams useful
65Examples for forms
66Forms are useful for all tests
Simple ticks may be sufficient
Empty space for comments and drawings
67Special 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
68A 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
69Not 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
70CT 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
71QC for Dosimetry Equipment
- Local standard
- 2 yearly calibration
- Field instruments
- yearly calibration
- Linearity
- Leakage
- Recombination
PTW
72QC for Measuring Equipment
- Automated scanners
- Positional accuracy
- Alignment
- Accuracy of data analysis
- Accessories
- Thermometer
- Barometer
73Clinical QC
- Not only physics and dosimetry must be subject to
QC, also clinical management - A good way to do this are chart rounds
74Chart Rounds
- Regular review of patients
- Can be all patients or randomly selected patients
- Should include all patients with unexpected
severe complications
75Treatment Verification - do not check individual
links in the chain but verify the overall outcome
Treatment verification
76Treatment 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
77Example for verificationWHO/IAEA photon dose
intercomparison
TLD capsules
Level 1 Intercomparison Dose in Reference
Conditions
78Treatment verification
- May be suitable for external audits
- Should verify localization of the radiation beam
AND the dose delivered - Could include in vivo dosimetry
794. 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
80QA in medical exposures
- Physical QA as discussed before
- Process QA
Leer
81QA 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
82Also the radiation protection program itself
requires QA
- Check that the program meets its objectives
- Document improvements
- Document and rectify deficiencies
- Raise awareness
83The cost of QA
- Dedicated staff - qualifications, training and
numbers - Equipment - include allowance for redundancy
- Time - commissioning, QA, reports, meetings,
training
84What do we get?
Yes, correct - lots of documentation. But there
are other benefits...
85The 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
86Additional 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
87Involvement 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
88But - 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...
89What 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
90What 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!
91Where 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 ClÃnicos y FÃsicos, PAHO,
Washington, DC (1986).
92WHO (World Health Organisation). Quality
Assurance in radiotherapy. Geneva 1988.
93Summary
- 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.
94Any questions?
95Question
- Please give an example for the concept of
Continuous Quality Improvement from your practice.
96Example 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...
97Acknowledgment
- Lee Collins, Westmead Hospital, Sydney
- Lyn Oliver, Royal North Shore Hospital, Sydney