12. medical exposure: quality assurance (2,359 kb)

1. Radiation Protection in Radiotherapy Part 12 Quality Assurance IAEA Training Material on Radiation Protection in Radiotherapy

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, Publicacin Cientifica No. 499, Control de Calidad en Radioterapia: Aspectos Clnicos y Fsicos , 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



...

(c) written records of relevant procedures and results;

(d) verification of the appropriate calibration and conditions of operation of dosimetry and monitoring equipment; .


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



...

and

(e) as far as possible, regular and independent quality audit reviews of the quality assurance programme for radiotherapy procedures


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


As a minimum, sections should exist for

Administrative procedures

Clinical procedures

Treatment procedures

Physics procedures

Radiation safety


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 Area Professional

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: > 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 Radiotherapy Examples 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


Safety interlocks

emergency

wedge etc

Light/ radiation field coincidence

Scales

Isocentre position

Cross hair position

PTW


Field size indicators

Distance measuring indicators

Jaw symmetry

Latching of wedges, trays etc.

Wedge position (factors etc.)

RMI

55. Quality Control - Annual

Dosimetry

Safety

Mechanical These 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: > 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


Weekly

Accuracy of source and dummy loading

Source positioning

At each source change or quarterly

Calibration

Timer function

Accuracy of source guides and connectors


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 verification: WHO/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 1994;21:581-618.

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. 24:1558-98; 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, Publicacin Cientifica No. 499, Control de Calidad en Radioterapia: Aspectos Clnicos y Fsicos, 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

12. medical exposure: quality assurance (2,359 kb)

Documents

acpsem position paper

bss appendix ii

quality assurance committee

quality assurance program

quality assurance team

radiation protection program

quality assurance

qc activities