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1、Radiation Protection inRadiotherapyPart 13Part 13Accidents and EmergenciesIAEA Training Material on Radiation Protection in RadiotherapyRadiation Protection in RadiotherapyPotential for an Accident in Radiotherapyl lRadiotherapy is unique from the point of view of radiation safety, since:n nit is th
2、e only application of radiation it is the only application of radiation sources in which very high doses are given sources in which very high doses are given on purpose to a part of a human body on purpose to a part of a human body n nnot only the tumour - normal tissue also not only the tumour - no
3、rmal tissue also receives doses comparable with the dose receives doses comparable with the dose to the tumourto the tumour2Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyPotential for accidentsl lFor workersl lFor patientsl lFor general public3Part 13, lecture 1: AccidentsRadiatio
4、n Protection in RadiotherapyPotential for accidentsl lFor workersFor workersl lFor patientsl lFor general publicFor general publicl lPart 8Part 8l lMedical Exposurel lPart 17Part 17While accidents affecting workers and general public are covered in other parts of the course, some aspects of dealing
5、with an accident and/or an emergency are independent of the group of persons involved - therefore this part is also relevant to these other parts.4Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyObjectivesl lBe aware of the potential for accidental Be aware of the potential for acci
6、dental radiation exposures affecting patients in radiation exposures affecting patients in radiotherapyradiotherapyl lBe able to develop an effective plan for Be able to develop an effective plan for emergencies and accident preventionemergencies and accident preventionl lBe familiar with emergency
7、response Be familiar with emergency response strategiesstrategiesl lTo identify the information which needs to be To identify the information which needs to be reported in case of an emergencyreported in case of an emergency5Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyContentsl
8、lLecture 1: Accidental medical exposure and potential exposure in radiotherapyl lLecture 2: Emergency preparedness and response6Part 13, lecture 1: AccidentsRadiation Protection inRadiotherapyPart 13Part 13Accidents and EmergenciesLecture 1: AccidentsLecture 1: AccidentsIAEA Training Material on Rad
9、iation Protection in RadiotherapyRadiation Protection in RadiotherapyObjectivesl lBe aware of the potential for accidental radiation exposures affecting patients in radiotherapyl lAnalyze accidents and be able to define lessons to be learnedl lBe able to develop an effective plan for prevention of a
10、ccidental exposures8Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyContents1. The potential for accidental exposures in radiotherapy2. Lessons learned from previous accidents3. Accident prevention9Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyPotential Exposurel
11、lIAEA Safety Series 120 and glossary of BSS: “ Exposure that is not expected with certainty to be delivered but that may result from an accident at a source or owing to an event or a sequence of events of a probabilistic nature, including equipment failures and operating errors.”10Part 13, lecture 1
12、: AccidentsRadiation Protection in Radiotherapy1. Potential for accidents in radiotherapyl lHuman error:-A therapeutic treatment was delivered to the wrong patientA therapeutic treatment was delivered to the wrong patient-A A therapeutic therapeutic treatment treatment was was delivered delivered to
13、 to the the wrong wrong treatment sitetreatment site-A A therapeutic therapeutic treatment treatment was was delivered delivered with with a a substantially substantially different different dose dose or or dose dose fraction fraction to to that that prescribed prescribed by by the the medical pract
14、itionermedical practitionerl lEquipment malfunction11Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccidents in radiotherapyl lWe dont have to We dont have to look far.look far.12Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyA case study.l lStaffn nFive radiatio
15、n oncologistsFive radiation oncologistsn nTwo medical physicists and one dosimetristTwo medical physicists and one dosimetristn nFour radiotherapy technologistsFour radiotherapy technologistsl lTwo shifts from 6 am to 9 pml lTwo radiation oncologists (one in the morning and one in the evening) in Ho
16、spital Arosemena on a monthly rotation13Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyWorkload - a normal radiotherapy departmentl l70 to 80 patients per 70 to 80 patients per daydayl lMultiple fields and Multiple fields and beam shaping beam shaping devices (shielding devices (sh
17、ielding blocks and wedges)blocks and wedges)l lAll fields every dayAll fields every dayl lSSD technique for SSD technique for multiple fieldsmultiple fields14Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyThe treatment planning systeml l2 D planningl lMultidata RTP/2l lVersion 11,
18、installed in 1993l lAllows for n nBrachytherapyBrachytherapyn nExternal beamExternal beaml lRestriction to four blocks per field15Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyTreatment PlanningEntering blocks separatelyl lAdd 1 block Add 1 block l lType transmission Type transmis
19、sion factor factor l lDigitize contourDigitize contourl lRepeat the Repeat the procedure with other procedure with other blocksblocks16Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyThe event was triggeredl lIn April 2000 radiation In April 2000 radiation oncologists expressed the
20、oncologists expressed the demand to use a fifth demand to use a fifth (central) block(central) blockl lA temporary solution was A temporary solution was found to calculate only for found to calculate only for the central block the central block l lIgnoring the other four Ignoring the other four bloc
21、ks in the calculation of blocks in the calculation of the dose to specified point the dose to specified point Standard blocksAdditionalblock17Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyOvercoming the limitation on the number of blocksl lIn August 2000 one physicist came up with
22、 In August 2000 one physicist came up with another solution: to enter several blocks at another solution: to enter several blocks at once. once. l lBUT BUT the procedure was not writtenthe procedure was not writtenl lAnother physicist entered the data in a Another physicist entered the data in a sim
23、ilar but slightly different waysimilar but slightly different way18Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyTreating 4 blocks as oneComputer calculates correct treatment timeTwo loops in opposite directions19Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyTre
24、ating 4 blocks as one (another way)Computer accepts input and calculates wrong treatment time by about + 100 % (for 5% transmission factor of the blocks)Two loops in the same direction20Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapySummary l lThe treatment time was The treatment t
25、ime was approximately twiceapproximately twicel lExample: similar Example: similar treatment on another treatment on another patients 0.6 min (one patients 0.6 min (one field) as compared with field) as compared with more than 1.2 minmore than 1.2 minl lThe computer printout The computer printout pr
26、ovides distorted provides distorted isodoses and the longer isodoses and the longer treatment time but the treatment time but the icon with the four blocksicon with the four blocks21Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyThe discovery of the accidentl lIn November 2000 a ra
27、diation oncologist In November 2000 a radiation oncologist started to observe diarrhoea, which was started to observe diarrhoea, which was unusually prolongedunusually prolongedl lIn December 2000 the effect was observed in In December 2000 the effect was observed in other patientsother patientsl lT
28、he physicists examined the charts but did The physicists examined the charts but did not find any abnormality (the computer not find any abnormality (the computer calculation was not questioned)calculation was not questioned)22Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyThe disc
29、overy of the accidentl lIn March 2001 the isodoses and the treatment time were reexamined closer and found differences in isodose shape and different treatment timesl lThe treatment was simulated on a water phantom and measurement of doses were made which confirmed higher dose.23Part 13, lecture 1:
30、AccidentsRadiation Protection in RadiotherapyDoses to patients were calculated manuallyl lBased on the dose ratel lThe treatment times from the patients charts, as well as all other treatment parametersl lSince the fractions were higher than normal, the biologically effective dose and the dose equiv
31、alent to a treatment of 2 Gy/fraction were also calculated24Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyNumber of Patients and their doses (equivalent to 2 Gy/fraction)As of May 30, 2000Dose GyN ofpat.25Part 13, lecture 1: AccidentsRadiation Protection in Radiotherapy26Part 13,
32、lecture 1: AccidentsRadiation Protection in RadiotherapyResults to Date (May 30, 2000)l l8 Deaths of 28 patientsl l5 Radiation relatedl l2 Unknown. Not enough datal l1 Due to metastatic cancerl l20 Surviving patients27Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyInitiating event
33、and contributory factorsl lThe event was triggered byThe event was triggered byn nThe search for a way to overcome the limitation of The search for a way to overcome the limitation of the planning computer (four blocks only)the planning computer (four blocks only)l lContributory factorsContributory
34、factorsn nThe computer presented the icon as if the blocks The computer presented the icon as if the blocks were correctly recognizedwere correctly recognizedn nThe procedure was not testedThe procedure was not testedn nThe trick “worked” and was time savingThe trick “worked” and was time savingn nI
35、t was claimed that, in another TPS in Panama the It was claimed that, in another TPS in Panama the same way of data entry works wellsame way of data entry works well28Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyInitiating event and contributory factors (contd)l lContributory fac
36、tors (contd)Contributory factors (contd)n nProcedure not properly documentedProcedure not properly documentedn nTreatment times were longer than usual but no Treatment times were longer than usual but no one detected itone detected its sworkload workload s slimited interaction (radiation oncologists
37、, medical limited interaction (radiation oncologists, medical physicists and radiotherapy technologists)physicists and radiotherapy technologists)s sComputer calculations in general were not verifiedComputer calculations in general were not verifiedn nPatient reactions were realized but the follow-u
38、p Patient reactions were realized but the follow-up was insufficientwas insufficient29Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyPanama incident summaryl l2001l lMinor change of practice in use of a treatment planning systeml lNot systematically verifiedl l16 patients severely
39、overexposedl l8 patients deadl l a sobering experience30Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyNot an isolated eventl lMore than 90 cases More than 90 cases documenteddocumentedl lAffects Affects brachytherapy and brachytherapy and external beam external beam radiotherapyra
40、diotherapyl lAffects developed Affects developed and developing and developing countriescountries31Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyMajor documented accidents in Radiotherapy 32Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyConsequences of accidentsl
41、 lAccident may result in Accident may result in a deviation from the a deviation from the intended dose and/or intended dose and/or dose distribution:dose distribution:l lIf the dose is too low: If the dose is too low: impact on cure rateimpact on cure ratel lIf the dose is too high, If the dose is
42、too high, it may have an impact it may have an impact on:on:l lEarly (acute) Early (acute) complicationscomplicationsl lLate (chronic) Late (chronic) complicationscomplications33Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyConsequences of accidentsExternal and internal.34Part 13,
43、 lecture 1: AccidentsRadiation Protection in RadiotherapyConsequences in practicel lDose too low - reduction of tumour control probability. There is no second chance!l lDose too high - acute complicationsl lDose too high - late complications35Part 13, lecture 1: AccidentsRadiation Protection in Radi
44、otherapyAccidents in radiotherapyl lHorrific consequencesl lAn opportunity to learnn nThorough investigation requiredThorough investigation requiredn nNot necessarily about blameNot necessarily about blamen nReporting essentialReporting essentiall lWhat are the specific issues contributing to accide
45、nts in radiotherapy?36Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAnother examplel lZaragozaZaragoza, Spain, Spainn nBreakdown in bending magnet power supplyBreakdown in bending magnet power supplyn nRepair carried out by a company service Repair carried out by a company service
46、 techniciantechniciann nNo report made to Medical Physics before No report made to Medical Physics before treatment resumedtreatment resumedn nDuring the next 10 days, 27 patients were treated During the next 10 days, 27 patients were treated with electron beams having dose rates of with electron be
47、ams having dose rates of between 3 to 7 times above the expectedbetween 3 to 7 times above the expected37Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyFrequency of accidentsl lDifficult to estimate Difficult to estimate becausebecausen nnot all accidents not all accidents are repo
48、rtedare reportedn nthe frequency of the frequency of accidents is likely accidents is likely to vary significantly to vary significantly between different between different institutionsinstitutionsl lSome estimate in Some estimate in ICRU report 24 ICRU report 24 (1976)(1976)38Part 13, lecture 1: Ac
49、cidentsRadiation Protection in RadiotherapyPotential for accidental medical exposure in Radiotherapyl lthe patient is directly in the beam or sealed the patient is directly in the beam or sealed sources are placed in contact with the tissue: sources are placed in contact with the tissue: no structur
50、al shielding is in betweenno structural shielding is in betweenl lthere are a large number of steps from the there are a large number of steps from the prescription of the treatment to the delivery of prescription of the treatment to the delivery of the dose (compare Gthe dose (compare G Leunens Leu
51、nens et alet al. .: : “Garbage in Garbage out”“Garbage in Garbage out” Radiother Radiother. . Oncol Oncol. ). )39Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyPotential for an Accident in Radiotherapyl lmany records and communications are many records and communications are involv
52、ed in those steps, between different involved in those steps, between different professionals and even with the patient professionals and even with the patient l lthere is a combination of very different there is a combination of very different activities from the very manual (such as activities fro
53、m the very manual (such as tailored organ shielding preparation in the tailored organ shielding preparation in the workshop), to very sophisticated computer workshop), to very sophisticated computer assisted techniques and high technology assisted techniques and high technology equipmentequipment 41
54、Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyEarly Effects and Clinical Detection of Radiation Accidentsl lCareful clinical observation of patientsCareful clinical observation of patientsn nsignificant reduction in the rate of side-effects can significant reduction in the rate of
55、 side-effects can be an indicator of anbe an indicator of an underdosage underdosage accident accidentn nincreased complication rate can be an indicator increased complication rate can be an indicator ofof overdosage overdosage accident and of higher expectation accident and of higher expectation fo
56、r late effects as wellfor late effects as welll lExperienced radiation oncologists may be Experienced radiation oncologists may be able to differentiate as low as 7-8 % able to differentiate as low as 7-8 % differences in dose (with careful weekly differences in dose (with careful weekly patient fol
57、low-up)patient follow-up)42Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyThe dose response curvel lIs steep for tumor control - 5% Is steep for tumor control - 5% difference in dose can make difference in dose can make 15% difference in cure rate15% difference in cure ratel lAcute
58、 reactions may occur Acute reactions may occur during treatmentduring treatmentl lThere is a small normal rate of There is a small normal rate of severe complications - even a severe complications - even a small additional number of small additional number of severe or unusual severe or unusual comp
59、lications can be complications can be significantsignificant43Part 13, lecture 1: AccidentsRadiation Protection in Radiotherapy2. Lessons learnedl lNo learning without investigationl lBSS II.29. “Registrants and licensees shall promptly investigate any of the following incidents: (a) any therapeutic
60、 treatment delivered to either the (a) any therapeutic treatment delivered to either the wrong patient or the wrong tissue, or using the wrong wrong patient or the wrong tissue, or using the wrong pharmaceutical, or with a dose or dose fractionation pharmaceutical, or with a dose or dose fractionati
61、on differing substantially from the values prescribed by differing substantially from the values prescribed by the medical practitioner or which may lead to undue the medical practitioner or which may lead to undue acute secondary effects;”acute secondary effects;” 44Part 13, lecture 1: AccidentsRad
62、iation Protection in RadiotherapyLessons from Panama incidentl lAwareness in radiotherapy Awareness in radiotherapy l lTreatment planning is a critical deviceTreatment planning is a critical devicel lWritten proceduresWritten proceduresl lTest of new proceduresTest of new proceduresl lHand verificat
63、ion of computer calculationsHand verification of computer calculationsl lTreatment planning softwareTreatment planning softwaren nmanual of instructionsmanual of instructionsn nwarnings on screenwarnings on screenn nfoolproof testsfoolproof tests45Part 13, lecture 1: AccidentsRadiation Protection in
64、 RadiotherapyLessons (contd)l lAvailability of manufacturer servicel lWorkloadl lPresence and supervision by managersl lInteraction of professionals46Part 13, lecture 1: Accidentsbetter still to prevent accidents in the first place3. Accident PreventionRadiation Protection in RadiotherapyAccident Pr
65、evention: Knowing where to startl lWhat can go wrong?l lWhat can be the initiating events of accidents?l lWhat can be the contributing factors?l lWhat measures can be taken for prevention?48Part 13, lecture 1: AccidentsRadiation Protection in Radiotherapy“Lessons learned from accidental exposures in
66、 radiotherapy”49Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyIAEA Safety Report Series 17l lOnly reported accidentsl lTherefore likely bias towards countries with a reporting requirement and structurel lExternal beam and brachytherapyl lUnsealed sources (covered in training on Nu
67、clear Medicine)50Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccidental exposures in external beam RT can be grouped as follows:l lEquipment designl lCalibration of beamsl lMaintenancel lTreatment planning and dose calculationl lSimulationl lTreatment set-up and delivery51Part 1
68、3, lecture 1: AccidentsRadiation Protection in RadiotherapyAccidents in EBT52Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyEven before the equipment: facility design (part 7)l lthe possibility of accidental exposure can be minimised by measures such as positioning: n nthe control
69、room and the equipment within so the control room and the equipment within so that staff have a good view of the treatment that staff have a good view of the treatment roomroomn npatient and visitor waiting areas so that they patient and visitor waiting areas so that they are unlikely to enter treat
70、ment areas are unlikely to enter treatment areas accidentallyaccidentallyn npatient change areas so that the patient is patient change areas so that the patient is unlikely to enter a treatment area accidentallyunlikely to enter a treatment area accidentally53Part 13, lecture 1: AccidentsRadiation P
71、rotection in RadiotherapyExample: Equipmentl lEquipment designEquipment designl lCalibration of beamsCalibration of beamsl lMaintenanceMaintenancel lTreatment planning Treatment planning and dose calculationand dose calculationl lSimulationSimulationl lTreatment set-up Treatment set-up and deliverya
72、nd deliveryl lPart 10Part 10l lFail to safetyFail to safetyl lRedundant safety Redundant safety featuresfeaturesl lFollow IEC Follow IEC standardsstandardsl lManuals and Manuals and documentationdocumentationl lCommissioningCommissioning54Part 13, lecture 1: AccidentsRadiation Protection in Radiothe
73、rapyExample: Calibrationl lEquipment designEquipment designl lCalibration of Calibration of beamsbeamsl lMaintenanceMaintenancel lTreatment planning Treatment planning and dose calculationand dose calculationl lSimulationSimulationl lTreatment set-up Treatment set-up and deliveryand deliveryl lPart
74、10Part 10l lFollow appropriate Follow appropriate protocolprotocoll lRegular consistency Regular consistency checkschecksl lIndependent checkIndependent checkl lAuditsAuditsl lDocumentationDocumentation55Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyExample: Maintenancel lEquipmen
75、t designEquipment designl lCalibration of beamsCalibration of beamsl lMaintenanceMaintenancel lTreatment planning Treatment planning and dose calculationand dose calculationl lSimulationSimulationl lTreatment set-up Treatment set-up and deliveryand deliveryl lPart 10Part 10l lGood trainingGood train
76、ingl lInclude preventative Include preventative maintenance (PMI)maintenance (PMI)l lCommunicationCommunicationl lFollow manufacturers Follow manufacturers proceduresproceduresl lDocumentationDocumentationl lCheck after each Check after each modificationmodification56Part 13, lecture 1: AccidentsRad
77、iation Protection in RadiotherapyExample: Planningl lEquipment designEquipment designl lCalibration of beamsCalibration of beamsl lMaintenanceMaintenancel lTreatment planning Treatment planning and dose and dose calculationcalculationl lSimulationSimulationl lTreatment set-up Treatment set-up and de
78、liveryand deliveryl lPart 10Part 10l lTrainingTrainingl lIndependent checksIndependent checksl lQAQAl lDocumentationDocumentationl lParticipation in Participation in intercomparisonsintercomparisonsl lIn vivoIn vivo dosimetry dosimetry57Part 13, lecture 1: AccidentsRadiation Protection in Radiothera
79、pyExample: Simulatorl lEquipment designEquipment designl lCalibration of beamsCalibration of beamsl lMaintenanceMaintenancel lTreatment planning Treatment planning and dose calculationand dose calculationl lSimulationSimulationl lTreatment set-up Treatment set-up and deliveryand deliveryl lParts 5 a
80、nd 10Parts 5 and 10l lInterdisciplinary Interdisciplinary communicationcommunicationl lProtocolsProtocolsl lQAQAl lCommissioning Commissioning (systematic (systematic differences between differences between treatment unit and treatment unit and simulator?)simulator?)58Part 13, lecture 1: AccidentsRa
81、diation Protection in RadiotherapyExample: Set-upl lEquipment designEquipment designl lCalibration of beamsCalibration of beamsl lMaintenanceMaintenancel lTreatment planning Treatment planning and dose calculationand dose calculationl lSimulationSimulationl lTreatment set-up Treatment set-up and del
82、iveryand deliveryl lPart 10Part 10l lPortal filmsPortal filmsl lIn vivoIn vivo dosimetry dosimetryl lTwo people at Two people at treatment unittreatment unitl lIndependent checksIndependent checksl lRecord and verify Record and verify systemsysteml lDocumentationDocumentation59Part 13, lecture 1: Ac
83、cidentsQuick DiscussionWhat would be common features of the strategies to prevent different causes of accidents in radiotherapy?Radiation Protection in RadiotherapyStrategies for accident prevention in external beam RTl lQuality assurancel lIndependent checksl lGood trainingl lGood communicationl lD
84、ocumentationl l.61Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyStrategies for accident prevention in external beam RTl lQuality assurancel lIndependent checksl lGood trainingl lDocumentationl lCan they also be applied to brachytherapy?62Part 13, lecture 1: AccidentsRadiation Prot
85、ection in RadiotherapyAn Accident with Remote Afterloadingl lArea monitor giving an alarm - assumed faultyl lIn fact, the source wire was broken and the source was still in the patientl lPatient returned to wardl lReceived 16,000 Gy at 1 cm instead of the planned 18 Gy!l lPatient died!63Part 13, lec
86、ture 1: AccidentsRadiation Protection in RadiotherapyAccidental exposures for brachy-therapy can be grouped as followsl lEquipment designl lSource order and deliveryl lSource calibration and acceptancel lSource preparation for the treatmentl lTreatment planning and dose calculationl lSource removal6
87、4Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccidents in Brachytherapy65Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyNotel lConsidering the number of patients treated, the relative number of accidents in brachytherapy is approximately 10 times higher than in
88、 EBTl lTreatment planning and source calibration are the most important factors in bothl lIssues related to the radioactive source are important in brachytherapy66Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyIssues for accidents in brachytherapyl lEquipment designEquipment design
89、l lSource order and Source order and deliverydeliveryl lSource calibration Source calibration and acceptanceand acceptancel lSource preparation Source preparation for the treatmentfor the treatmentl lTreatment planning Treatment planning and dose and dose calculationcalculationl lSource removalSourc
90、e removall lPart 11, compare also Part 11, compare also comments on EBTcomments on EBTl lAuthorizationAuthorizationl lTransportTransportl lRecord keepingRecord keepingl lHandling of sources - Handling of sources - equipmentequipmentl lAccounting of sourcesAccounting of sourcesl lDisposal, discharge
91、of Disposal, discharge of patientspatients67Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccident prevention: General featuresl lTraining, training, trainingl lDefence in depthl lDocumentationl lEmergency equipmentl lQuality Assurance system68Part 13, lecture 1: AccidentsRadiatio
92、n Protection in RadiotherapyAccident Prevention: Trainingl lRadiotherapy physics (calibration), Radiotherapy physics (calibration), maintenance, radiation oncologists, maintenance, radiation oncologists, technologists, nurses for brachytherapytechnologists, nurses for brachytherapyl lSpecific traini
93、ng use of the machine, including Specific training use of the machine, including not only radiation equipment but also not only radiation equipment but also treatment planning systemtreatment planning system. .l lInclude training to detect and deal with Include training to detect and deal with unusu
94、al events and situationsunusual events and situationsl lReassessment of needs for staff and training Reassessment of needs for staff and training as patient workload increases and each time as patient workload increases and each time a new equipment or technique is introduced.a new equipment or tech
95、nique is introduced.69Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyEducation and trainingl lFollowing the national or regional Following the national or regional recommendations by professional societiesrecommendations by professional societiesl lThe education and training of the
96、 various The education and training of the various professionals has to include case histories of professionals has to include case histories of accidents and their preventionaccidents and their preventionl lInformative lecturers on cases histories and Informative lecturers on cases histories and ac
97、cident prevention should also be accident prevention should also be addressed to the hospital managersaddressed to the hospital managers70Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccident Prevention: Defence-in-depth l lIAEA Safety Fundamentals (SS 120, 1996): IAEA Safety Fun
98、damentals (SS 120, 1996): “The application of more than a single “The application of more than a single protection measure for a given safety protection measure for a given safety objective such that objective such that the objective is achieved the objective is achieved even if one of the protectiv
99、e measures failseven if one of the protective measures fails.” .”l le.g.e.g.: redundant and independent calibration, : redundant and independent calibration, external audits, external audits, in vivoin vivo dosimetry, dosimetry, participation in TLD postal servicesparticipation in TLD postal service
100、s71Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccident Preventionl lDefence-in-depth (independent verification) applied to radiotherapy could have prevented all reported major accidents related to the commissioning of a new beam (calibration) or a TPS72Part 13, lecture 1: Accid
101、entsRadiation Protection in RadiotherapyDefence in depthl lAn example of possible defence-in-depth steps available for calibration of a 60-Co unit:1. Formal procedure for calibration of the new beam1. Formal procedure for calibration of the new beam2. Check of consistency between the measured 2. Che
102、ck of consistency between the measured dose rate and the certificate of the radiation dose rate and the certificate of the radiation sourcesource3. Another person determines the dose rate 3. Another person determines the dose rate independently before starting patients treatmentsindependently before
103、 starting patients treatments73Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyDefence in depthl lCo-60 teletherapy unit calibration (contd):4. Use of IAEA/WHO TLD Postal Dose Check 4. Use of IAEA/WHO TLD Postal Dose Check Service Service 5. Periodic re-measurements of the beam and
104、5. Periodic re-measurements of the beam and comparison with decaycomparison with decay6. External audits 6. External audits 7. Close observation of patients for side effects and 7. Close observation of patients for side effects and complicationscomplicationsl lA Quality Assurance programme has to in
105、tegrate sufficient defence in depth 74Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAn example of defence-in-depth for maintenance:1. Maintenance strategy condition to authorize import of 1. Maintenance strategy condition to authorize import of equipmentequipment2. Training of mai
106、ntenance engineers on that particular 2. Training of maintenance engineers on that particular model of equipment and of the consequences of model of equipment and of the consequences of misadjustment of physical parameters (including accident misadjustment of physical parameters (including accident
107、case histories)case histories)3. Formal transfer of the equipment for maintenance and 3. Formal transfer of the equipment for maintenance and back to the medical physicistback to the medical physicist4. Test of the equipment before resuming treatments4. Test of the equipment before resuming treatmen
108、ts5. Training of the staff to identify displays and conflicting 5. Training of the staff to identify displays and conflicting signalssignals6. Equipment design preventing “beam on” when interlocks 6. Equipment design preventing “beam on” when interlocks or selectors disabled or selectors disabled 75
109、Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccident prevention (contd)l lOrganizationn nSufficient staff following recommendations Sufficient staff following recommendations on staffing (professional societies)on staffing (professional societies)n nWell defined functions and re
110、sponsibilitiesWell defined functions and responsibilitiesn nReview of staffing, responsibilities and Review of staffing, responsibilities and training as workload increases or new training as workload increases or new equipment or techniques are introducedequipment or techniques are introduced76Part
111、 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccident preventionl lCommunicationn nCommunication procedures for safety Communication procedures for safety critical issuescritical issuesn nRecording and reporting of treatments Recording and reporting of treatments following protocolsf
112、ollowing protocolsn nPrompt reporting of any unexpected Prompt reporting of any unexpected behavior of a machinebehavior of a machinen nPrompt reporting of unexpected reaction of Prompt reporting of unexpected reaction of a patient or of a series of patientsa patient or of a series of patients77Part
113、 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccident Prevention: Documentationl lProcesses and dataProcesses and datal lFormal commissioning for ALL equipment - Formal commissioning for ALL equipment - documentationdocumentationl lFormal equipment transfer for maintenanceFormal equi
114、pment transfer for maintenancel lWritten documentationWritten documentationl lMinutes of meetings - signed and approvedMinutes of meetings - signed and approvedl lKeep important information in duplicate (Keep important information in duplicate (e.g.e.g. beam data should be kept in two different beam
115、 data should be kept in two different locations)locations)78Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyWritten Proceduresl lavailable to relevant personsl lconcise instructionsl lspecify immediate actionl lidentify responsible personsl ldrawings and diagrams usefull lflowcharts
116、79Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyExample: 60-Co source jam.80Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccident preventionl lICRP 86: ChecklistsICRP 86: Checklists81Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyEmergency Equ
117、ipmentl lManual, procedures, documentationl lRadiation monitorl lOther items as required by the specific application, e.g.:n nspill kitn nemergency lead containern nblood collection (for biological monitoring)82Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccident prevention: QAl
118、 lAll previous items integrated into a QA programl lCompare also part 12 of the course83Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAccident Preventionl lOf importance are also: 1) regulatory requirements,1) regulatory requirements,2) managerial responsibilities and measures,2)
119、managerial responsibilities and measures,3) ensuring that measures are observed by 3) ensuring that measures are observed by each staff involved and,each staff involved and,l lTraining on accident prevention for health authorities and hospital managers and all staff on shop floor84Part 13, lecture 1
120、: AccidentsRadiation Protection in RadiotherapyDissemination of information within professional communityl lA chance to learnl lMake sure legal investigations are not interfered withl lMake sure no one can be identified85Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyLessons learne
121、d : Summaryl lAdherence to established safety procedures would Adherence to established safety procedures would have prevented most accidentshave prevented most accidentsl lSystematic audits by management help to ensure Systematic audits by management help to ensure that level of knowledge and perfo
122、rmance of staff is that level of knowledge and performance of staff is maintainedmaintainedl lA poor A poor safety culturesafety culture can result in degradation of can result in degradation of safety systems and proceduressafety systems and proceduresl lDeficient training is contributory in the ma
123、jority of Deficient training is contributory in the majority of accidentsaccidents86Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyWhere to get more informationlCosset JM. Irradiation accidents lessons for oncology? Radiother. Oncol. 63: 1-10, 2002lInternational Atomic Energy Agenc
124、y. Lessons learned from accidental exposures in radiotherapy. Safety Report Series: N17. 2000. lInternational Commission on Radiological Protection. Prevention of Accidental Exposures to patients undergoing radiation therapy, ICRP report 86. Oxford: Pergamon Press; 2001.87Part 13, lecture 1: Acciden
125、tsAny questions?Radiation Protection in RadiotherapyQuestion:l lAssume the following scenario: A shielding Assume the following scenario: A shielding block has been omitted for the eye of a block has been omitted for the eye of a patient treated with external beam therapy for patient treated with ex
126、ternal beam therapy for one day. Please discuss:one day. Please discuss:?The consequences for the patientThe consequences for the patient?The actions to be takenThe actions to be taken?Methods to prevent this accident happening in the Methods to prevent this accident happening in the futurefuture89Part 13, lecture 1: AccidentsRadiation Protection in RadiotherapyAcknowledgmentl lPedro Ortiz Lpez, IAEAl lModupe Oresegun, IAEA90Part 13, lecture 1: Accidents
