Radiation Protection inRadiation Protection in
RadiotherapyRadiotherapy
Part 10Part 10
Good Practice including RadiationGo...
Part 10, lecture 3 (cont.): Radiotherapy treatme2Radiation Protection in Radiotherapy
C. CommissioningC. Commissioning
Com...
Part 10, lecture 3 (cont.): Radiotherapy treatme3Radiation Protection in Radiotherapy
Acceptance testing andAcceptance tes...
Part 10, lecture 3 (cont.): Radiotherapy treatme4Radiation Protection in Radiotherapy
Some equipment requiredSome equipmen...
Part 10, lecture 3 (cont.): Radiotherapy treatme5Radiation Protection in Radiotherapy
CommissioningCommissioning
A. Non-do...
Part 10, lecture 3 (cont.): Radiotherapy treatme6Radiation Protection in Radiotherapy
A. Non-dose componentsA. Non-dose co...
Part 10, lecture 3 (cont.): Radiotherapy treatme7Radiation Protection in Radiotherapy
Electron and photon beamsElectron an...
Part 10, lecture 3 (cont.): Radiotherapy treatme9Radiation Protection in Radiotherapy
B. Photon calculation testsB. Photon...
Part 10, lecture 3 (cont.): Radiotherapy treatme10Radiation Protection in Radiotherapy
Photon calculation tests (cont.)Pho...
Part 10, lecture 3 (cont.): Radiotherapy treatme11Radiation Protection in Radiotherapy
Photon calculation tests (cont.)Pho...
Part 10, lecture 3 (cont.): Radiotherapy treatme12Radiation Protection in Radiotherapy
C. Electron calculationC. Electron ...
Part 10, lecture 3 (cont.): Radiotherapy treatme13Radiation Protection in Radiotherapy
E. Data transferE. Data transfer
Pi...
Part 10, lecture 3 (cont.): Radiotherapy treatme14Radiation Protection in Radiotherapy
F. Special proceduresF. Special pro...
Part 10, lecture 3 (cont.): Radiotherapy treatme15Radiation Protection in Radiotherapy
Sources of uncertaintySources of un...
Part 10, lecture 3 (cont.): Radiotherapy treatme16Radiation Protection in Radiotherapy
Typical accuracy requiredTypical ac...
Part 10, lecture 3 (cont.): Radiotherapy treatme17Radiation Protection in Radiotherapy
Typical accuracy requiredTypical ac...
Part 10, lecture 3 (cont.): Radiotherapy treatme18Radiation Protection in Radiotherapy
Time and staff requirements forTime...
Part 10, lecture 3 (cont.): Radiotherapy treatme19Radiation Protection in Radiotherapy
Some ‘tricky’ issuesSome ‘tricky’ i...
Part 10, lecture 3 (cont.): Radiotherapy treatme20Radiation Protection in Radiotherapy
Commissioning summaryCommissioning ...
Quick Question:Quick Question:
What ‘commissioning’ needs to be done for a handWhat ‘commissioning’ needs to be done for a...
Part 10, lecture 3 (cont.): Radiotherapy treatme22Radiation Protection in Radiotherapy
Superficial beamSuperficial beam
HV...
Part 10, lecture 3 (cont.): Radiotherapy treatme23Radiation Protection in Radiotherapy
Quality Assurance of a treatmentQua...
Part 10, lecture 3 (cont.): Radiotherapy treatme24Radiation Protection in Radiotherapy
Aspects of QA (compare alsoAspects ...
Part 10, lecture 3 (cont.): Radiotherapy treatme25Radiation Protection in Radiotherapy
Quality AssuranceQuality Assurance
Part 10, lecture 3 (cont.): Radiotherapy treatme26Radiation Protection in Radiotherapy
Quality AssuranceQuality Assurance
...
Part 10, lecture 3 (cont.): Radiotherapy treatme27Radiation Protection in Radiotherapy
Frequency of tests for planning (an...
Part 10, lecture 3 (cont.): Radiotherapy treatme28Radiation Protection in Radiotherapy
Frequency of tests (cont.)Frequency...
Part 10, lecture 3 (cont.): Radiotherapy treatme29Radiation Protection in Radiotherapy
Treatment planning QA summaryTreatm...
Quick Question:Quick Question:
How much time should be spent on treatmentHow much time should be spent on treatment
planni...
Part 10, lecture 3 (cont.): Radiotherapy treatme31Radiation Protection in Radiotherapy
Staff and time requirementsStaff an...
Part 10, lecture 3 (cont.): Radiotherapy treatme32Radiation Protection in Radiotherapy
QA in treatment planningQA in treat...
Part 10, lecture 3 (cont.): Radiotherapy treatme33Radiation Protection in Radiotherapy
QC of treatment plansQC of treatmen...
Part 10, lecture 3 (cont.): Radiotherapy treatme34Radiation Protection in Radiotherapy
QC of treatment plansQC of treatmen...
Part 10, lecture 3 (cont.): Radiotherapy treatme35Radiation Protection in Radiotherapy
Who should do it?Who should do it?
...
Part 10, lecture 3 (cont.): Radiotherapy treatme36Radiation Protection in Radiotherapy
Example for physics treatment sheet...
Part 10, lecture 3 (cont.): Radiotherapy treatme37Radiation Protection in Radiotherapy
Example for physics treatment sheet...
Part 10, lecture 3 (cont.): Radiotherapy treatme38Radiation Protection in Radiotherapy
Example for physics treatment sheet...
Part 10, lecture 3 (cont.): Radiotherapy treatme39Radiation Protection in Radiotherapy
Example for physics treatment sheet...
Part 10, lecture 3 (cont.): Radiotherapy treatme40Radiation Protection in Radiotherapy
Treatment plan QA summaryTreatment ...
Quick Question:Quick Question:
What advantages has a multidisciplinaryWhat advantages has a multidisciplinary
approach to ...
Part 10, lecture 3 (cont.): Radiotherapy treatme42Radiation Protection in Radiotherapy
Did we achieve the objectives?Did w...
Part 10, lecture 3 (cont.): Radiotherapy treatme43Radiation Protection in Radiotherapy
Overall SummaryOverall Summary
Trea...
Any questions?Any questions?
Question:Question:
Please label and discuss the following processes inPlease label and discuss the following processes in
...
Part 10, lecture 3 (cont.): Radiotherapy treatme46Radiation Protection in Radiotherapy
Question:Question:
Patient
Treatmen...
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  • Part 10: Optimization in External Beam Radiotherapy
    Lesson 4: Treatment Planning
    Learning objectives: Upon completion of this lesson, the students will be able to:
    Understand the general principles of radiotherapy treatment planning
    Appreciate different dose calculation algorithms
    Understand the need for testing the treatment plan against a set of measurements
    Be able to apply the concepts of optimization of medical exposure throughout the treatment planning process
    Appreciate the need for quality assurance in radiotherapy treatment planning
    Activity: Lecture - 2 practical sessions: 1 Hand planning using isodose plots, 2 Monitor unit calculations
    Duration: 2 hours
    References:
    J van Dyk et al. 1993 Commissioning and QA of treatment planning computers. Int. J. Radiat. Oncol. Biol. Phys. 26: 261-273
    J van Dyk et al, 1999 Computerised radiation treatment planning systems. In: Modern Technology of Radiation Oncology (Ed.: J Van Dyk) Chapter 8. Medical Physics Publishing, Wisconsin, ISBN 0-944838-38-3, pp. 231-286.
    M Millar et al 1997 ACPSEM position paper. Australas. Phys. Eng. Sci. Med. 20 Supplement
    B Fraass et al 1998 AAPM Task Group 53: QA for clinical RT planning. Med. Phys. 25: 1773-1829
  • The last section of lecture 3 in part 10 is mainly concerned with computerized treatment planning, however, many points are also relevant for manual treatment planning.
  • This is a difference which often overlooked by administrators - it can result in vastly different time estimates.
  • The picture shows the set-up of a scanning water phantom
  • These are different aspects of the commissioning of computerised treatment planning - the lecture follows this outline...
  • The ruler illustrates the need for quantitative geometric information
  • This should all be familiar to the participants from the previous section of the lecture. The next slide is a reminder which is currently hidden.
    The lecturer should point out that the planning system (and any system which allows manual calculation of dose) must ‘know’ all this information
  • Hidden slide
  • The first test is equally applicable to computerized treatment planning systems and hand planning.
    Machine settings include what gantry angles and field sizes are allowed, what wedges fit where and what set-up requirements there may be.
  • All these tests can be performed in the water phantom shown...
  • Illustrated is a CIRS phantom
    In vivo dosimetry is discussed in more detail in the next lecture in part 10.
  • In a computerized world every step must be verified. For example, there are many conventions for patient orientation available - it must be ensured that a lesion on the left side of the brain is also represented on the left side in the data used for planning… (in general it is not easy to tell which side is which in a brain scan - are we looking at the patient from the head or the toes?)
  • This is just a summary - it would be beyond the scope of the course to provide more details on any of these.
  • This is an important slide - it summarizes the uncertainties which will affect the realization of a treatment plan in practice.
  • This is an important point:
    In regions where the dose is relatively homogenous (not much change of dose in the area of interest) on has to look primarily to the uncertainty in dose calculation.
    In regions of strong dose gradients this is not possible as the dose changes very rapidly and a small misplacement results in a large change in dose. Here it is more appropriate to characterize the dose calculation algorithm in terms of distance to agreement.
  • Important information for administrators - a new treatment planning system will not be available for clinical use a couple of days after installation.
  • Other aspects of QA are covered in part 12 of the course.
  • This slide is included in three lectures of the course - some repetition is useful and it helps participants to feel familiar within the course.
  • This slide preempts some of the discussions of part 12 of the course. However, it was felt that it would be beneficial for participants to discuss QA of treatment planning close to the introduction of the planning systems themselves.
  • The last point should be seen in the context of the material presented in the 4th lecture of part 10
  • This is a different aspect than the QA of planning systems - the QA here is directed towards the treatment plan of an individual patient.
  • This slide is too small to be read (see slides 37-39 for bigger text). The text could be handed out to participants. However, it may be better to just use this to emphasize that:
    this is a complex procedure
    it must be developed locally
    documentation is essential
    The next slide highlights just three points which should not be overlooked.
  • The key issues are:
    Communication and Documentation
  • The key issues are:
    Communication and Documentation
  • Again, the question can be omitted if deemed inappropriate, or if time is pressing.
    It is meant as a tool to get participants involved. The next slide provides some answers.
  • The next slide can be printed out for the students with its notes. The first process is already described. The participants shall discuss and label the additional processes.
    Important keywords are:
    2: Electronic data transfer, digitisation of patient outlines, ensuring geometry, placement of beams
    3: Patient outlines, immobilisation devices, external markers
    4: Patient positioning, immobilisation
    5: Data transfer (including beam modifiers, blocks, MLC), verification images (DRRs)
    6: Simulator images
  • 1: It is essential to align the patient during any diagnostic procedure in a way which allows to reference the target anatomy to external landmarks. The latter may be bony landmarks or artificial marks like tattoos. In any case the procedure should allow the placement of external beams without repeating the diagnostic procedure. An important part of this is to perform the diagnostic procedure in the same patient position as the treatment.
    2:
    3:
    4:
    5:
  • rpop.iaea.org

    1. 1. Radiation Protection inRadiation Protection in RadiotherapyRadiotherapy Part 10Part 10 Good Practice including RadiationGood Practice including Radiation Protection in EBTProtection in EBT Lecture 3 (cont.): Radiotherapy Treatment PlanningLecture 3 (cont.): Radiotherapy Treatment Planning IAEA Training Material on Radiation Protection in Radiotherapy
    2. 2. Part 10, lecture 3 (cont.): Radiotherapy treatme2Radiation Protection in Radiotherapy C. CommissioningC. Commissioning Complex procedure depending very much onComplex procedure depending very much on equipmentequipment Protocols exist and should be followedProtocols exist and should be followed Useful literature:Useful literature: J van Dyk et al. 1993 Commissioning and QA of treatmentJ van Dyk et al. 1993 Commissioning and QA of treatment planning computers. Int. J. Radiat. Oncol. Biol. Phys. 26: 261-273planning computers. Int. J. Radiat. Oncol. Biol. Phys. 26: 261-273 J van Dyk et al, 1999 Computerised radiation treatment planningJ van Dyk et al, 1999 Computerised radiation treatment planning systems.systems. In: Modern Technology of Radiation Oncology (Ed.: JIn: Modern Technology of Radiation Oncology (Ed.: J Van Dyk) ChapterVan Dyk) Chapter 88. Medical Physics Publishing, Wisconsin,. Medical Physics Publishing, Wisconsin, ISBN 0-944838-38-3, pp.ISBN 0-944838-38-3, pp. 231-286231-286..
    3. 3. Part 10, lecture 3 (cont.): Radiotherapy treatme3Radiation Protection in Radiotherapy Acceptance testing andAcceptance testing and commissioningcommissioning Acceptance testing:Acceptance testing: Check that the system conforms withCheck that the system conforms with specifications.specifications. Documentation of specifications either in the tender, inDocumentation of specifications either in the tender, in guidelines or manufacturers’ notes – may test againstguidelines or manufacturers’ notes – may test against standard data (standard data (e.g.e.g. MillerMiller et al.et al. 1995, AAPM report 55)1995, AAPM report 55) Subset of commissioning procedureSubset of commissioning procedure Takes typically two weeksTakes typically two weeks Commissioning:Commissioning: Getting the system ready for clinical useGetting the system ready for clinical use Takes typically several months for modern 3D systemTakes typically several months for modern 3D system
    4. 4. Part 10, lecture 3 (cont.): Radiotherapy treatme4Radiation Protection in Radiotherapy Some equipment requiredSome equipment required Scanning beam data acquisition systemScanning beam data acquisition system Calibrated ionization chamberCalibrated ionization chamber Slab phantom includingSlab phantom including inhomogeneitiesinhomogeneities Radiographic filmRadiographic film Anthropomorphic phantomAnthropomorphic phantom Ruler, spirit levelRuler, spirit level
    5. 5. Part 10, lecture 3 (cont.): Radiotherapy treatme5Radiation Protection in Radiotherapy CommissioningCommissioning A. Non-dose related componentsA. Non-dose related components B. Photon dose calculationsB. Photon dose calculations C. Electron dose calculationsC. Electron dose calculations (D. Brachytherapy - covered in part 11)(D. Brachytherapy - covered in part 11) E. Data transferE. Data transfer F. Special proceduresF. Special procedures
    6. 6. Part 10, lecture 3 (cont.): Radiotherapy treatme6Radiation Protection in Radiotherapy A. Non-dose componentsA. Non-dose components Image inputImage input Geometry and scaling ofGeometry and scaling of Digitizer,Digitizer, ScansScans OutputOutput Text informationText information Anatomical structure informationAnatomical structure information CT numbersCT numbers Structures (outlining tools, non-axialStructures (outlining tools, non-axial reconstruction, “capping”,…)reconstruction, “capping”,…)
    7. 7. Part 10, lecture 3 (cont.): Radiotherapy treatme7Radiation Protection in Radiotherapy Electron and photon beamsElectron and photon beams Description (machine, modality, energy)Description (machine, modality, energy) Geometry (Gantry, collimator, table,Geometry (Gantry, collimator, table, arcs)arcs) Field definition (Collimator, trays, MLC,Field definition (Collimator, trays, MLC, applicators, …)applicators, …) Beam modifiers (Wedges, dynamicBeam modifiers (Wedges, dynamic wedges, compensators, bolus,…)wedges, compensators, bolus,…) NormalizationNormalization
    8. 8. Part 10, lecture 3 (cont.): Radiotherapy treatme9Radiation Protection in Radiotherapy B. Photon calculation testsB. Photon calculation tests Point dosesPoint doses TAR, TPR, PDD, PSFTAR, TPR, PDD, PSF Square, rectangular and irregular fieldsSquare, rectangular and irregular fields Inverse square lawInverse square law Attenuation factors (trays, wedges,…)Attenuation factors (trays, wedges,…) Output factorsOutput factors Machine settingsMachine settings
    9. 9. Part 10, lecture 3 (cont.): Radiotherapy treatme10Radiation Protection in Radiotherapy Photon calculation tests (cont.)Photon calculation tests (cont.) Dose distributionDose distribution HomogenousHomogenous Profiles (open and wedged)Profiles (open and wedged) SSD/SADSSD/SAD Contour correctionContour correction Blocks, MLC, asymmetric jawsBlocks, MLC, asymmetric jaws Multiple beamsMultiple beams ArcsArcs Off axis (open and wedged)Off axis (open and wedged) Collimator/couch rotationCollimator/couch rotation PTW waterphantom
    10. 10. Part 10, lecture 3 (cont.): Radiotherapy treatme11Radiation Protection in Radiotherapy Photon calculation tests (cont.)Photon calculation tests (cont.) Dose distributionDose distribution InhomogeneousInhomogeneous Slab geometrySlab geometry Other geometriesOther geometries Anthropomorphic phantomAnthropomorphic phantom In vivoIn vivo dosimetry at least for thedosimetry at least for the first patientsfirst patients Following the incident in Panama, the IAEAFollowing the incident in Panama, the IAEA recommends a largely extendedrecommends a largely extended in vivoin vivo dosimetrydosimetry program to be implementedprogram to be implemented
    11. 11. Part 10, lecture 3 (cont.): Radiotherapy treatme12Radiation Protection in Radiotherapy C. Electron calculationC. Electron calculation Similar to photons, however, additional:Similar to photons, however, additional: Bremsstrahlung tailBremsstrahlung tail Small field sizes require special considerationSmall field sizes require special consideration Inhomogeneity has more impactInhomogeneity has more impact It is possible to use reference data forIt is possible to use reference data for comparison (Shuicomparison (Shui et al.et al. 1992 “Verification1992 “Verification data for electron beam dose algorithms” Med.data for electron beam dose algorithms” Med. Phys. 19: 623-636)Phys. 19: 623-636)
    12. 12. Part 10, lecture 3 (cont.): Radiotherapy treatme13Radiation Protection in Radiotherapy E. Data transferE. Data transfer Pixel values, CT numbersPixel values, CT numbers Missing linesMissing lines Patient/scan informationPatient/scan information OrientationOrientation Distortion, magnificationDistortion, magnification All needs verification!!!
    13. 13. Part 10, lecture 3 (cont.): Radiotherapy treatme14Radiation Protection in Radiotherapy F. Special proceduresF. Special procedures JunctionsJunctions Electron abuttingElectron abutting Stereotactic proceduresStereotactic procedures Small field procedures (Small field procedures (e.g.e.g. for eyefor eye treatment)treatment) IMRTIMRT TBI, TBSITBI, TBSI Intraoperative radiotherapyIntraoperative radiotherapy
    14. 14. Part 10, lecture 3 (cont.): Radiotherapy treatme15Radiation Protection in Radiotherapy Sources of uncertaintySources of uncertainty Patient localizationPatient localization Imaging (resolution, distortions,…)Imaging (resolution, distortions,…) Definition of anatomy (outlines,…)Definition of anatomy (outlines,…) Beam geometryBeam geometry Dose calculationDose calculation Dose display and plan evaluationDose display and plan evaluation Plan implementationPlan implementation
    15. 15. Part 10, lecture 3 (cont.): Radiotherapy treatme16Radiation Protection in Radiotherapy Typical accuracy requiredTypical accuracy required (examples)(examples) Square field CAX:Square field CAX: 1%1% MLC penumbra: 3%MLC penumbra: 3% Wedge outer beam:Wedge outer beam: 5%5% Buildup-region: 30%Buildup-region: 30% 3D inhomogeneity3D inhomogeneity CAX: 5%CAX: 5% From AAPM TG53
    16. 16. Part 10, lecture 3 (cont.): Radiotherapy treatme17Radiation Protection in Radiotherapy Typical accuracy requiredTypical accuracy required (examples)(examples) Square field CAX:Square field CAX: 1%1% MLC penumbra: 3%MLC penumbra: 3% Wedge outer beam:Wedge outer beam: 5%5% Buildup-region: 30%Buildup-region: 30% 3D inhomogeneity3D inhomogeneity CAX: 5%CAX: 5% Note: Uncertainties have two components: Dose (given in %) Location (given in mm)
    17. 17. Part 10, lecture 3 (cont.): Radiotherapy treatme18Radiation Protection in Radiotherapy Time and staff requirements forTime and staff requirements for commissioning (J Van Dyk 1999)commissioning (J Van Dyk 1999) Photon beam: 4-7 daysPhoton beam: 4-7 days Electron beam: 3-5 daysElectron beam: 3-5 days Brachytherapy: 1 day per source typeBrachytherapy: 1 day per source type Monitor unit calculation: 0.3 days perMonitor unit calculation: 0.3 days per beambeam
    18. 18. Part 10, lecture 3 (cont.): Radiotherapy treatme19Radiation Protection in Radiotherapy Some ‘tricky’ issuesSome ‘tricky’ issues Dose Volume Histograms - watch sampling,Dose Volume Histograms - watch sampling, grid, volume determination, normalizationgrid, volume determination, normalization (1% volume represents still > 10E7 cells!)(1% volume represents still > 10E7 cells!) Biological parameters - Tumour ControlBiological parameters - Tumour Control Probability (TCP) and Normal TissueProbability (TCP) and Normal Tissue Complication Probability (NTCP) depend onComplication Probability (NTCP) depend on the model used and the parameters whichthe model used and the parameters which are available.are available.
    19. 19. Part 10, lecture 3 (cont.): Radiotherapy treatme20Radiation Protection in Radiotherapy Commissioning summaryCommissioning summary Probably the most complex task for RTProbably the most complex task for RT physicists - takes considerable time and trainingphysicists - takes considerable time and training Partial commissioning needed for systemPartial commissioning needed for system upgrades and modificationupgrades and modification Documentation and hardcopy data must beDocumentation and hardcopy data must be includedincluded Training is essential and courses are availableTraining is essential and courses are available Independent check highly recommendedIndependent check highly recommended
    20. 20. Quick Question:Quick Question: What ‘commissioning’ needs to be done for a handWhat ‘commissioning’ needs to be done for a hand calculation method of treatment times for a superficialcalculation method of treatment times for a superficial X Ray treatment unit?X Ray treatment unit?
    21. 21. Part 10, lecture 3 (cont.): Radiotherapy treatme22Radiation Protection in Radiotherapy Superficial beamSuperficial beam HVLHVL Percentage depth dose (may be look up table)Percentage depth dose (may be look up table) Normalization point (typically the surface)Normalization point (typically the surface) Scatter (typically back scatter) factorScatter (typically back scatter) factor Applicator and/or cone factorApplicator and/or cone factor Timer accuracyTimer accuracy On/off effectOn/off effect Other effects which may affect dose (Other effects which may affect dose (e.g.e.g. electronelectron contamination)contamination)
    22. 22. Part 10, lecture 3 (cont.): Radiotherapy treatme23Radiation Protection in Radiotherapy Quality Assurance of a treatmentQuality Assurance of a treatment planning systemplanning system QA is typically a subset of commissioningQA is typically a subset of commissioning teststests Protocols:Protocols: As for commissioning and:As for commissioning and: M MillarM Millar et al.et al. 1997 ACPSEM position paper.1997 ACPSEM position paper. Australas. Phys. Eng. Sci. Med. 20 SupplementAustralas. Phys. Eng. Sci. Med. 20 Supplement B FraasB Fraas et al.et al. 1998 AAPM Task Group 53: QA for1998 AAPM Task Group 53: QA for clinical RT planning. Med. Phys. 25: 1773-1829clinical RT planning. Med. Phys. 25: 1773-1829
    23. 23. Part 10, lecture 3 (cont.): Radiotherapy treatme24Radiation Protection in Radiotherapy Aspects of QA (compare alsoAspects of QA (compare also part 12 of the course)part 12 of the course) Training - qualified staffTraining - qualified staff Checks against a benchmark -Checks against a benchmark - reproducibilityreproducibility Treatment verificationTreatment verification QA administrationQA administration CommunicationCommunication DocumentationDocumentation Awareness of procedures requiredAwareness of procedures required
    24. 24. Part 10, lecture 3 (cont.): Radiotherapy treatme25Radiation Protection in Radiotherapy Quality AssuranceQuality Assurance
    25. 25. Part 10, lecture 3 (cont.): Radiotherapy treatme26Radiation Protection in Radiotherapy Quality AssuranceQuality Assurance Check prescription Hand calculation of treatment time
    26. 26. Part 10, lecture 3 (cont.): Radiotherapy treatme27Radiation Protection in Radiotherapy Frequency of tests for planning (andFrequency of tests for planning (and suggested acceptance criteria)suggested acceptance criteria) Commissioning and significant upgradesCommissioning and significant upgrades See aboveSee above Annual:Annual: MU calculation (2%)MU calculation (2%) Reference plan set (2% or 2mm)Reference plan set (2% or 2mm) Scaling/geometry input/output devices (1mm)Scaling/geometry input/output devices (1mm) MonthlyMonthly Check sumCheck sum Some reference test setsSome reference test sets
    27. 27. Part 10, lecture 3 (cont.): Radiotherapy treatme28Radiation Protection in Radiotherapy Frequency of tests (cont.)Frequency of tests (cont.) WeeklyWeekly Input/output devicesInput/output devices Each time system is turned onEach time system is turned on Check sum (no change)Check sum (no change) Each planEach plan CT transfer - orientation?CT transfer - orientation? Monitor units - independent checkMonitor units - independent check Verify input parameters (field size, energy,Verify input parameters (field size, energy, etc.etc.))
    28. 28. Part 10, lecture 3 (cont.): Radiotherapy treatme29Radiation Protection in Radiotherapy Treatment planning QA summaryTreatment planning QA summary Training most essentialTraining most essential Staying alert is part of QAStaying alert is part of QA Documentation and reporting necessaryDocumentation and reporting necessary Treatment verificationTreatment verification in vivoin vivo can playcan play an important rolean important role
    29. 29. Quick Question:Quick Question: How much time should be spent on treatmentHow much time should be spent on treatment planning QC?planning QC?
    30. 30. Part 10, lecture 3 (cont.): Radiotherapy treatme31Radiation Protection in Radiotherapy Staff and time requirementsStaff and time requirements (source J. Van Dyk(source J. Van Dyk et al.et al. 1999)1999) Reproducibility tests/QC: 1 week perReproducibility tests/QC: 1 week per yearyear In vivoIn vivo dosimetry: about 1 hour perdosimetry: about 1 hour per patient - aim for about 10% of patientspatient - aim for about 10% of patients Manual check of plans and monitorManual check of plans and monitor units: 20 minutes per planunits: 20 minutes per plan
    31. 31. Part 10, lecture 3 (cont.): Radiotherapy treatme32Radiation Protection in Radiotherapy QA in treatment planningQA in treatment planning The planning system QA of the system Plan of a patient QA of the plan
    32. 32. Part 10, lecture 3 (cont.): Radiotherapy treatme33Radiation Protection in Radiotherapy QC of treatment plansQC of treatment plans Treatment plan:Treatment plan: Documentation ofDocumentation of treatment set-up,treatment set-up, machine parameters,machine parameters, calculation details,calculation details, dose distribution,dose distribution, patient information,patient information, record and verifyrecord and verify datadata Consists typically of:Consists typically of: Treatment sheetTreatment sheet Isodose planIsodose plan Record and VerifyRecord and Verify entryentry Reference filmsReference films (simulator, DRR)(simulator, DRR)
    33. 33. Part 10, lecture 3 (cont.): Radiotherapy treatme34Radiation Protection in Radiotherapy QC of treatment plansQC of treatment plans Check plan for each patient prior toCheck plan for each patient prior to commencement of treatmentcommencement of treatment Plan must bePlan must be Complete from prescription to set-upComplete from prescription to set-up information and dose delivery adviseinformation and dose delivery advise Understandable by colleaguesUnderstandable by colleagues Document treatment for future useDocument treatment for future use
    34. 34. Part 10, lecture 3 (cont.): Radiotherapy treatme35Radiation Protection in Radiotherapy Who should do it?Who should do it? Treatment sheet checking should involveTreatment sheet checking should involve senior staffsenior staff It is an advantage if different professionsIt is an advantage if different professions can be involved in the processcan be involved in the process Reports must go to clinicians and theReports must go to clinicians and the relevant QA committeerelevant QA committee
    35. 35. Part 10, lecture 3 (cont.): Radiotherapy treatme36Radiation Protection in Radiotherapy Example for physics treatment sheetExample for physics treatment sheet checking procedurechecking procedure 1. Check prescription (energy/dose/fractionation is everything signed ?) 2. Check prescription and calculation page for consistency: Isocentric (SAD) or fixed distance (SSD) set-up ? Are all necessary factors used? Check both,dose/fraction and number of fractions. 3. Check normalisation value (Plan or data sheets). 4. Check outline, separation and prescription depth. 5. Turn to treatment plan: Does it look ok ? Outline ? Bolus ? Isocentre placement and normalisation point ? Any concerns regarding the use of algorithms near surfaces or inhomogeneities? Would you expect problems in planes not shown ? Prescription ? 6. Check and compare with treatment sheet calculation page: treatment unit and type, field names, weighting, wedges, blocks, field size (FS), focus surface distance (FSD), Tissue Air Ratio (TAR) (if isocentric treatment) - is this consistent with entries in treatment log page? 7. Electrons only: … 8. Photons only: … 9. Check shadow tray factor, wedge factor. Are any other attenuation factors required (e.g. couch, headrest, table tray...) ? 10. Check inverse square law factor (in electron treatments: is the virtual FSD appropriate?) 11. Calculate monitor units. Is time entry ok ? 12. Check if critical organ (e.g. spinal cord, lens, scrotum) dose or hot spot dose is required. If so, is it calculated correctly ? 13. Suggest in vivo dosimetry measurements if appropriate. Sign calculation sheet (if everything is ok). 14. Compare results on calculation page with entries in treatment log. 15. Check diagram and/or set up description: is there anything else worth to consider ? 16. Sign top of treatment sheet (specify what parts where checked if not all fields were checked). 17. Contact planning staff if required. Sign off physics log book.
    36. 36. Part 10, lecture 3 (cont.): Radiotherapy treatme37Radiation Protection in Radiotherapy Example for physics treatment sheetExample for physics treatment sheet checking procedurechecking procedure 1. Check prescription (energy/dose/fractionation is everything signed ?) 2. Check prescription and calculation page for consistency: Isocentric (SAD) or fixed distance (SSD) set-up ? Are all necessary factors used? Check both,dose/fraction and number of fractions. 3. Check normalisation value (Plan or data sheets). 4. Check outline, separation and prescription depth. 5. Turn to treatment plan: Does it look ok ? Outline ? Bolus ? Isocentre placement and normalisation point ? Any concerns regarding the use of algorithms near surfaces or inhomogeneities? Would you expect problems in planes not shown ? Prescription ?
    37. 37. Part 10, lecture 3 (cont.): Radiotherapy treatme38Radiation Protection in Radiotherapy Example for physics treatment sheetExample for physics treatment sheet checking procedure (cont.)checking procedure (cont.) 6. Check and compare with treatment sheet calculation page: treatment unit and type, field names, weighting, wedges, blocks, field size (FS), focus surface distance (FSD), Tissue Air Ratio (TAR) (if isocentric treatment) - is this consistent with entries in treatment log page? 7. Electrons only: … 8. Photons only: … 9. Check shadow tray factor, wedge factor. Are any other attenuation factors required (e.g. couch, headrest, table tray...) ? 10. Check inverse square law factor (in electron treatments: is the virtual FSD appropriate?) 11. Calculate monitor units. Is time entry ok ? 12. Check if critical organ (e.g. spinal cord, lens, scrotum) dose or hot spot dose is required. If so, is it calculated correctly ?
    38. 38. Part 10, lecture 3 (cont.): Radiotherapy treatme39Radiation Protection in Radiotherapy Example for physics treatment sheetExample for physics treatment sheet checking procedure (cont.)checking procedure (cont.) 13. Suggest in vivo dosimetry measurements if appropriate. Sign calculation sheet (if everything is ok). 14. Compare results on calculation page with entries in treatment log. 15. Check diagram and/or set up description: is there anything else worth to consider ? 16. Sign top of treatment sheet (specify what parts where checked if not all fields were checked). 17. Contact planning staff if required. Sign off physics log book.
    39. 39. Part 10, lecture 3 (cont.): Radiotherapy treatme40Radiation Protection in Radiotherapy Treatment plan QA summaryTreatment plan QA summary Essential part of departmental QAEssential part of departmental QA Part of patient recordsPart of patient records Multidisciplinary approachMultidisciplinary approach
    40. 40. Quick Question:Quick Question: What advantages has a multidisciplinaryWhat advantages has a multidisciplinary approach to QC of treatment plans?approach to QC of treatment plans?
    41. 41. Part 10, lecture 3 (cont.): Radiotherapy treatme42Radiation Protection in Radiotherapy Did we achieve the objectives?Did we achieve the objectives? Understand the general principles ofUnderstand the general principles of radiotherapy treatment planningradiotherapy treatment planning Appreciate different dose calculationAppreciate different dose calculation algorithmsalgorithms Be able to apply the concepts of optimizationBe able to apply the concepts of optimization of medical exposure throughout the treatmentof medical exposure throughout the treatment planning processplanning process Appreciate the need for quality assurance inAppreciate the need for quality assurance in radiotherapy treatment planningradiotherapy treatment planning
    42. 42. Part 10, lecture 3 (cont.): Radiotherapy treatme43Radiation Protection in Radiotherapy Overall SummaryOverall Summary Treatment planning is the most importantTreatment planning is the most important step towards radiotherapy for individualstep towards radiotherapy for individual patients - as such it is essential for patientpatients - as such it is essential for patient protection as outlined in BSSprotection as outlined in BSS Treatment planning is growing more complexTreatment planning is growing more complex and time consumingand time consuming Understanding of the process is essentialUnderstanding of the process is essential QA of all aspects is essentialQA of all aspects is essential
    43. 43. Any questions?Any questions?
    44. 44. Question:Question: Please label and discuss the following processes inPlease label and discuss the following processes in external beam radiotherapy treatment.external beam radiotherapy treatment.
    45. 45. Part 10, lecture 3 (cont.): Radiotherapy treatme46Radiation Protection in Radiotherapy Question:Question: Patient Treatment unit Diagnostic tools Treatment planning 1 3 5 4 2 6

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