Part VIII:Medical Exposures in Radiotherapy Acceptance testing & Quality Assurance Lecture 8 :...

Part VIII:Medical Exposures in Part VIII:Medical Exposures in RadiotherapyRadiotherapy

Lecture 8 : Acceptance testing & Quality Acceptance testing & Quality Assurance Assurance

IAEA Post Graduate Educational Course on Radiation Protection and Safe Use of Radiation Sources

Module 4. Quality Assurance

Part VIII.4.8 Acceptance testing & Quality Assurance Acceptance testing & Quality Assurance Slide 2

ObjectiveObjective• To appreciate the need for Quality assurance and To appreciate the need for Quality assurance and

Quality control in Radiation therapyQuality control in Radiation therapy• To familiarize with the procedures for quality control To familiarize with the procedures for quality control

at various stages of Radiation therapy processat various stages of Radiation therapy process• To understand the basic quality control tests for To understand the basic quality control tests for

Simulator, Treatment planning system, dose Simulator, Treatment planning system, dose delivery, and teletherapy equipmentdelivery, and teletherapy equipment

• To understand & appreciate the requirements of To understand & appreciate the requirements of routine quality assurance procedures for LDR and routine quality assurance procedures for LDR and HDR remote after loading units.HDR remote after loading units.


What is Quality?What is Quality?

• The quality can be defined as ‘the totality of features The quality can be defined as ‘the totality of features of a product or service that bears its ability to satisfy of a product or service that bears its ability to satisfy given needs’given needs’

• quality relates to quality relates to – Fitness for useFitness for use– Fitness for purposeFitness for purpose– Quality refers to certain standards and the ways Quality refers to certain standards and the ways

and means by which those standards are and means by which those standards are achieved, maintained and improved uponachieved, maintained and improved upon


What is Quality system?What is Quality system?

• Quality system is the total QA process for the Quality system is the total QA process for the total organization or for specific functional total organization or for specific functional areas within the organization.areas within the organization.

• Purpose : To provide management control Purpose : To provide management control over the activities that affect the quality of over the activities that affect the quality of service deliveredservice delivered


What is meant by Quality What is meant by Quality Assurance? Assurance?

• Quality assurance is ‘ all those planned and systematic Quality assurance is ‘ all those planned and systematic actions necessary to provide adequate confidence that a actions necessary to provide adequate confidence that a product or a service will satisfy given requirements for product or a service will satisfy given requirements for quality’quality’

• In radiation Therapy QA is ‘ all those procedures that In radiation Therapy QA is ‘ all those procedures that ensure consistency of the medical prescription and the ensure consistency of the medical prescription and the safe fulfillment of the prescription as regards to the safe fulfillment of the prescription as regards to the target volume, together with minimal dose to normal target volume, together with minimal dose to normal tissue, minimal exposure of personal, and adequate tissue, minimal exposure of personal, and adequate patient monitoring aimed at determining the end result of patient monitoring aimed at determining the end result of treatment’treatment’


What is Quality Control?What is Quality Control?

• Quality control is the ‘regulatory process Quality control is the ‘regulatory process through which the actual quality performance through which the actual quality performance is measured compared to existing standards is measured compared to existing standards and finally the actions necessary to keep or and finally the actions necessary to keep or regain conformance with the standards’ regain conformance with the standards’


What are the components of Quality What are the components of Quality control in Radiation oncology?control in Radiation oncology?

• Specification of the product or processSpecification of the product or process– Defined prior to purchase or Defined prior to purchase or – The initial standards measured during The initial standards measured during

commissioningcommissioning• Measurement of PerformanceMeasurement of Performance• Inspection or measurement or service of the product Inspection or measurement or service of the product

to determine conformance to specificationto determine conformance to specification• Feedback to ensure that the measure has met the Feedback to ensure that the measure has met the

specification or device to regain the standardspecification or device to regain the standard


QA and QCQA and QC

• Quality Assurance is the overall process Quality Assurance is the overall process which is supported by Quality Control which is supported by Quality Control activitiesactivities

• Quality Control describes the actual Quality Control describes the actual mechanisms and procedures by which one mechanisms and procedures by which one can assure qualitycan assure quality


QA Cost-BenefitQA Cost-Benefit

• Benefit of QA comes at a costBenefit of QA comes at a cost• Very little QA effort Very little benefitVery little QA effort Very little benefit• Too much QA effort does not increase the benefitToo much QA effort does not increase the benefit• Need to optimize the QA effort - Balance between to Need to optimize the QA effort - Balance between to

little and too muchlittle and too much

Svensson GK


A Comprehensive QA Program A Comprehensive QA Program typically comprises oftypically comprises of

• Quality Assurance CommitteeQuality Assurance Committee• Policies and Procedures ManualPolicies and Procedures Manual• Quality Assurance teamQuality Assurance team• Quality auditQuality audit• ResourcesResources


Policies and ProceduresPolicies and ProceduresRecommended steps in procedures developmentRecommended steps in procedures development• Review current practiceReview current practice• Analyze current practiceAnalyze current practice• Develop & Release a draft procedureDevelop & Release a draft procedure• Review commentsReview comments• Revise and issue procedure for acceptanceRevise and issue procedure for acceptance• Obtain approvalObtain approval• Issue for useIssue for use• ImplementImplement• Monitor and reviewMonitor and review


What is Quality Audit? What is Quality Audit?

• Quality audit consists of a systematic and Quality audit consists of a systematic and independent (preferably external) review independent (preferably external) review (examination and evaluation) of the QA system(examination and evaluation) of the QA system– To determine whether the system is To determine whether the system is

implemented effectively andimplemented effectively and– Whether the activities and results produce Whether the activities and results produce

the required end-point complying with the required end-point complying with predetermined quality standards.predetermined quality standards.


Quality AuditQuality Audit

• Ideally performed by someone outside of the Ideally performed by someone outside of the organizationorganization

• ExamplesExamples– IAEA/WHO TLD program for check of dose IAEA/WHO TLD program for check of dose

in therapy unitsin therapy units– EQUAL program in EuropeEQUAL program in Europe– Audits of clinical trials participationAudits of clinical trials participation


Quality AuditQuality Audit• ““A systematic and independent examination A systematic and independent examination

and evaluation to determine whether quality and evaluation to determine whether quality activities and results comply with planned activities and results comply with planned arrangements and whether the arrangements arrangements and whether the arrangements are implemented effectively and are suitable to are implemented effectively and are suitable to achieve the objectives.”achieve the objectives.”

““Quality assurance in radiotherapy.”, Radiother. Oncol., 1995Quality assurance in radiotherapy.”, Radiother. Oncol., 1995


What are Quality Standards?What are Quality Standards?

• Quality standards are the criteria against which the Quality standards are the criteria against which the quality of any form of activity can be assessed.quality of any form of activity can be assessed.– Example : The field size measured should be Example : The field size measured should be

within 1mmwithin 1mm• While developing QA standards one should considerWhile developing QA standards one should consider

– Ease of useEase of use– DocumentationDocumentation– Frequency of faultsFrequency of faults– Cost Versus reliabilityCost Versus reliability


Quality SystemQuality System

• PurposePurpose– To provide management control over the To provide management control over the

activities that affect the quality of service activities that affect the quality of service delivered.delivered.

• People are a key ingredient for the quality People are a key ingredient for the quality service and the operational quality controlservice and the operational quality control


What is ISO 9000?What is ISO 9000?

• The International organization for The International organization for Standardization (ISO) has developed a Standardization (ISO) has developed a series of standards and guideline series of standards and guideline documents that aid the development of documents that aid the development of quality managementquality management

• ISO 9000 in itself is not a standard but ISO 9000 in itself is not a standard but generic term applying to a series of generic term applying to a series of standards and accompanying guidelinesstandards and accompanying guidelines


Quality Assurance (QA)Quality Assurance (QA)

• ISO 9000: “all those planned and systematic ISO 9000: “all those planned and systematic actions necessary to provide adequate actions necessary to provide adequate confidence that a product or service will confidence that a product or service will satisfy given requirements for quality”satisfy given requirements for quality”


Quality Control (QC)Quality Control (QC)

• ISO 9000: “the regulatory process through ISO 9000: “the regulatory process through which the actual quality performance is which the actual quality performance is measured, compared to existing standards measured, compared to existing standards and finally the actions necessary to keep or and finally the actions necessary to keep or regain the standards”regain the standards”


Total Quality Management (TQM)Total Quality Management (TQM)

• That aspect of overall management function that That aspect of overall management function that determines and implements the quality policy, and , as determines and implements the quality policy, and , as such, is the responsibility of top management”such, is the responsibility of top management”

• Leadership is the most important ingredient in the TQM Leadership is the most important ingredient in the TQM philosophyphilosophy

Quality Assurance does not stop Quality Assurance does not stop here!here!

The Quality Assurance Committee and The Quality Assurance Committee and the Quality Assurance team must the Quality Assurance team must

continuously monitor new information continuously monitor new information and implement this in their proceduresand implement this in their procedures


Continuous Quality ImprovementContinuous Quality Improvement

• Dynamic way to perform with a determination to Dynamic way to perform with a determination to improve in all areas”improve in all areas”– continuous, on-goingcontinuous, on-going

• CQI - many other acronyms are available for thisCQI - many other acronyms are available for this• Part of virtually all QA systemsPart of virtually all QA systems• Improved methods on cancer patient management Improved methods on cancer patient management

are documented in clinical trial reports.are documented in clinical trial reports.


Continuous Quality ImprovementContinuous Quality Improvement

• Quality assurance protocols are continuously under Quality assurance protocols are continuously under development in many countriesdevelopment in many countries

• Regular Quality Assurance meeting for all members Regular Quality Assurance meeting for all members of a Sectionof a Section

• Continuing education - lectures, workshops, journal Continuing education - lectures, workshops, journal clubs and must be available for all staffclubs and must be available for all staff


QA is not policing but it is perfecting the QA is not policing but it is perfecting the processprocess

• It is essential in a QA program that all It is essential in a QA program that all staff feel free to report errorsstaff feel free to report errors

• A non threatening environment must A non threatening environment must existexist

• Reward honesty with encouragementReward honesty with encouragement• Education is the key, not punishmentEducation is the key, not punishment

And finally QA is not a threat but an opportunity


QC in Radiation OncologyQC in Radiation Oncology

• Specification of product or processSpecification of product or process• Measurement of performanceMeasurement of performance• Comparison of measurement to specificationComparison of measurement to specification• Feedback to ensure that measurement has Feedback to ensure that measurement has

met specification or adjustments to regain the met specification or adjustments to regain the result within specificationresult within specification


Why Quality system in Radiation Why Quality system in Radiation Oncology?Oncology?

• A Quality system raises morale of personnelA Quality system raises morale of personnel• A quality system increases efficiencyA quality system increases efficiency• QA reduces the likelihood of accidents and QA reduces the likelihood of accidents and

errorserrors• QA reduces the chance of litigationQA reduces the chance of litigation


QA in Radiation TherapyQA in Radiation Therapy

• Every step in Radiation therapy from diagnosis to Every step in Radiation therapy from diagnosis to treatment should have a proper quality control treatment should have a proper quality control system in place. system in place.

• Radiation therapy involves use of equipment form Radiation therapy involves use of equipment form diagnosis to treatment and periodic QA program diagnosis to treatment and periodic QA program should be available for testing the performance of should be available for testing the performance of these unitsthese units


Quality Control in radiotherapyQuality Control in radiotherapy

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


What comprises the QA in Radiation What comprises the QA in Radiation TherapyTherapy

• Quality Assurance in Radiation Therapy involvesQuality Assurance in Radiation Therapy involves1.1. Treatment planningTreatment planning

– Simulator, compensators, customized Simulator, compensators, customized shielding, castsshielding, casts

2.2. Clinical DosimetryClinical Dosimetry• Water phantom system, Local standard, Water phantom system, Local standard,

electrometer electrometer • Treatment time calculationTreatment time calculation

3.3. Treatment: Treatment: • Treatment unit, treatment setup Treatment unit, treatment setup


What is the frequency of the QA What is the frequency of the QA checks?checks?

• Frequency of the QA checks in Radiotherapy Frequency of the QA checks in Radiotherapy treatment varies at different levelstreatment varies at different levels

• Some areSome are– daily,daily,– weeklyweekly – monthlymonthly – yearlyyearly– depending on the performancedepending on the performance


Quality assurance at Treatment Quality assurance at Treatment Planning stagePlanning stage

QA of SimulatorQA of Simulator

QA of Simulator consists of series of Quality control QA of Simulator consists of series of Quality control tests, which can be divided astests, which can be divided as

1.1. Mechanical and Optical parameters: Mechanical and Optical parameters:

2.2. X-ray beam parameters (X-ray beam parameters (Image forming system)Image forming system)

3.3. Performance of Image IntensifierPerformance of Image Intensifier


Mechanical and Optical parameters:Mechanical and Optical parameters:

• Verification of Field SizeVerification of Field Size • Isocentre checkIsocentre check• Check on radiation field – light field congruenceCheck on radiation field – light field congruence

Star shot – isocentre check Optical – Radiation Field alignment


X-ray beam parameters X-ray beam parameters ((Image forming system)Image forming system)

• Verification of kV and mAVerification of kV and mA• Consistency of x-ray outputConsistency of x-ray output• Timer checkTimer check• Focal spot sizeFocal spot size• Tube leakage testTube leakage test

mAs & KVp meter

X-ray output


X-ray beam parameters X-ray beam parameters ((Image forming system)Image forming system)

• Focal spot sizeFocal spot size• Verification of kV and mAVerification of kV and mA• Consistency of x-ray outputConsistency of x-ray output• Timer checkTimer check• Tube leakage testTube leakage test

Verification of focal spot size


Performance of Image IntensifierPerformance of Image Intensifier

• ResolutionResolution , , Low contrast performanceLow contrast performance

Resolution check of Image intensifier Contrast check – the Leeds disc


What are the Safety tests on What are the Safety tests on Simulator?Simulator?

Test Test

1.1. Door InterlockDoor Interlock

2.2. Motion enable/disable Motion enable/disable switchesswitches

3.3. Warning LightsWarning Lights

4.4. Emergency offEmergency off

5.5. Collision avoidanceCollision avoidance

Frequency of TestsFrequency of Tests

DailyDaily

DailyDaily

DailyDaily

DailyDaily

DailyDaily


What are the Daily quality control What are the Daily quality control tests on a simulator?tests on a simulator?

TestTest1.1. Optical checksOptical checks

Localizing lasersLocalizing lasersDistance indicator (SAD)Distance indicator (SAD)

2.2. Mechanical checksMechanical checksCross hair centeringCross hair centeringBlock tray centeringBlock tray centeringField size indicatorField size indicator

3.3. Safety checksSafety checksDoor interlockDoor interlockMotion & Warning lightsMotion & Warning lights

ToleranceTolerance

2mm2mm

2mm2mm

2mm2mm

2mm2mm

1mm per edge1mm per edge


Listing of Listing of Simulator QASimulator QA


Quality assurance of Treatment Quality assurance of Treatment planningplanning

Components of Quality assurance for treatment Components of Quality assurance for treatment planningplanning

• Training of staffTraining of staff– Understanding the algorithmUnderstanding the algorithm– Understanding the input requirementsUnderstanding the input requirements– Verification of beam dataVerification of beam data

• Reproducibility testsReproducibility tests• In vitro/vivo dosimetryIn vitro/vivo dosimetry


Quality control checks for planning Quality control checks for planning systemsystem

• HardwareHardware– Digitizer Digitizer – Plotter Plotter

– CT interface for image CT interface for image

transfertransfer • External beam dataExternal beam data

– Data set Data set – Reference Field size planReference Field size plan– Monitor UnitsMonitor Units

Frequency of checkFrequency of checkweekly checkweekly check

weekly checkweekly check

System turn onSystem turn on

semi-annuallysemi-annually

semi-annuallysemi-annually

Each patientEach patient


In Vitro / in vivo dosimetry checksIn Vitro / in vivo dosimetry checks

• In vitro dosimetry with In vitro dosimetry with Anthropomorphic phantom Anthropomorphic phantom (Rando)(Rando)

• This phantom could be CT This phantom could be CT scanned and planned like scanned and planned like patient patient

• Phantom could be loaded Phantom could be loaded with TLD and treatemnt plan with TLD and treatemnt plan could be verifiedcould be verified

Rando Phantom


In vivo dosimetryIn vivo dosimetry

• Verification of dose Verification of dose delivereddelivered

• Dose to Critical organs – Dose to Critical organs – eyes, gonads or fetuseyes, gonads or fetus

• Exit dosimetryExit dosimetry• DetectorsDetectors

– Diode, MOS-FET,Diode, MOS-FET,– TLDTLD

TLD readerMOSFET detectors


Quality assurance of Teletherapy unit Quality assurance of Teletherapy unit

(Telecobalt & Linear accelrator)(Telecobalt & Linear accelrator)• Mechanical movementsMechanical movements• Radiation field alignmentRadiation field alignment• Radiation ON indicatorsRadiation ON indicators• Source ON/OFF Source ON/OFF

mechanism (Telecobalt)mechanism (Telecobalt)• Safety interlocksSafety interlocks


Mechanical checks on a teletherapy Mechanical checks on a teletherapy unit unit

• Rotational movementsRotational movementsVerification of mechanical vs digital indicatorVerification of mechanical vs digital indicator

– Gantry angle indicatorGantry angle indicator– Couch position indicatorCouch position indicator– Collimator angle indicatorCollimator angle indicator

• Field Size Field Size • Isocentre checkIsocentre check

Mechanical position indicator


Field size checkField size check

• Verification of Optical field with field size Verification of Optical field with field size indicator indicator (maximum tolerance 1mm on all sides)(maximum tolerance 1mm on all sides)

• verification of field size forverification of field size for

Various gantry anglesVarious gantry angles

Field size verification plates


Radiation / Light-Field Congruence Radiation / Light-Field Congruence

• Optical field used to setup Optical field used to setup patient and the radiation filed patient and the radiation filed should matchshould match

• Error in radiation and light field Error in radiation and light field congruence could lead to congruence could lead to geographical miss of the geographical miss of the tumourtumour

• Should be verified weeklyShould be verified weekly


Isocentre checkIsocentre check

• Isocentre verification forIsocentre verification for– GantryGantry– CouchCouch– CollimatorCollimator

• Wandering of Crosswire center for 360Wandering of Crosswire center for 360oo rotation rotation


Verification of IsocentreVerification of Isocentre

• Verification of Isocentre wandering for gantryVerification of Isocentre wandering for gantry


Verification of SSD indicatorVerification of SSD indicator

• Optical SSD indicator to be verified withOptical SSD indicator to be verified with

Mechanical front pointers for various SSDsMechanical front pointers for various SSDs

Front pointer

Front pointers for Different SSDs


Verification of Laser alignment Verification of Laser alignment

• Isocentre alignment to be checkedIsocentre alignment to be checked• Wrong indication of isocentre by lasers will Wrong indication of isocentre by lasers will

result in geographical missresult in geographical miss


QA of Telecobalt Safety featuresQA of Telecobalt Safety features

• Indicator ON lightsIndicator ON lights• Radiation area monitor – audio and visible indicators Radiation area monitor – audio and visible indicators

function function • Source ON Mechanical indicator on the Source ON Mechanical indicator on the

treatment unittreatment unit• Source ON indicator light at the doorSource ON indicator light at the door• Function of Emergency OFF switchFunction of Emergency OFF switch

Radiation area monitor


Radiation beam check – Telecobalt Radiation beam check – Telecobalt unitunit

• Radiation output for cobalt – to be checked Radiation output for cobalt – to be checked once a month for cobalt once a month for cobalt

• Energy check – not required for telecobaltEnergy check – not required for telecobalt• Timer to be checked dailyTimer to be checked daily


QA QA work work sheet sheet

for for CobaCoba

ltlt


Radiation Output & Energy CheckRadiation Output & Energy Check(Linear accelerator)(Linear accelerator)

• Radiation output for Linac – to Radiation output for Linac – to be checked daily for both be checked daily for both photon and electron beamsphoton and electron beams

• Energy check – to be done Energy check – to be done dailydaily

• Index for energy – TMRIndex for energy – TMR20/1020/10

• Radiation of dose at 20cm to Radiation of dose at 20cm to dose at 10cm at isocentric dose at 10cm at isocentric conditioncondition TMRTMR20/1020/10


Radiation beam check for LinacRadiation beam check for Linac

• Radiation beam flatness Radiation beam flatness • Beam symmetryBeam symmetry• PenumbraPenumbra• The above should be The above should be

checked once in six checked once in six monthsmonths

Beam profile - flatness


• QA work sheet forQA work sheet for

Linear acceleratorLinear accelerator


QA for Remote afterloading unit in QA for Remote afterloading unit in BrachytherapyBrachytherapy

• Radiation safety checksRadiation safety checks• Verification of source integrityVerification of source integrity• Verification of source position (dwell position)Verification of source position (dwell position)• Verification of dwell timeVerification of dwell time


Verification of source positionVerification of source position


Dwell position checkDwell position check

• Auto-radiograph to verify Auto-radiograph to verify the dwell position of the the dwell position of the HDR sourcesHDR sources


LDR source position check LDR source position check

QA kit for LDR auto-radiograph Auto-radiographLDR unit


SummarySummary

• Quality assurance is an important component Quality assurance is an important component of Radiotheray processof Radiotheray process

• QA procedures and policies must be setup QA procedures and policies must be setup and implemented at every stepand implemented at every step

• Proper QA tools should be usedProper QA tools should be used


SummarySummary

• QA has to be performed periodically for all the QA has to be performed periodically for all the steps involved in Radiotherapy.steps involved in Radiotherapy.

• QA should include mechanical movements, QA should include mechanical movements, radiation beam check and also radiation radiation beam check and also radiation safety checkssafety checks

• In the case of Treatment planning system QA In the case of Treatment planning system QA should include verification of input data and should include verification of input data and algorithm.algorithm.


QuestionsQuestions

• What is Quality Control?What is Quality Control?• What is Quality Assurance?What is Quality Assurance?• Why QA of simulator is a must?Why QA of simulator is a must?• What are the parameters to be checked for What are the parameters to be checked for

QA of Treatment planning systemQA of Treatment planning system• How often the output of Telecobalt unit has to How often the output of Telecobalt unit has to

be determined?be determined?


QuestionsQuestions

• What is radiation field congruence check?What is radiation field congruence check?• What additional checks on Radiation beam to What additional checks on Radiation beam to

be carried out for linac over cobalt units?be carried out for linac over cobalt units?• What is an auto-radiograph?What is an auto-radiograph?• How is an auto-radiograph useful as QA tool?How is an auto-radiograph useful as QA tool?


ReferencesReferences• ‘‘The Modern Technology of Radiation Oncology’ The Modern Technology of Radiation Oncology’

– Editor Jacob Van DykEditor Jacob Van Dyk

• The Physics of Radiation Therapy III EditionThe Physics of Radiation Therapy III Edition

– Faiz M KhanFaiz M Khan

• ‘Acceptance testing and commissioning of Ximatron Radiotherapy Simulator’ - Journal of Medical Physics, Vol.26, No.2

– B Paul Ravindran et al

• Design and implementation of a radiotherapy programme: clinical, medical physics, radiation protection and safety aspects - IAEA Tec Doc 1040

Part VIII:Medical Exposures in Radiotherapy Acceptance testing & Quality Assurance Lecture 8 :...

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