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Title: 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...