1、IAEAInternational Atomic Energy AgencyModule 2.10:Accident update some newer events(UK,USA,France)IAEA Training CourseIAEAQuestionsDo you think the accidents have not happened in recent years?Do you think well-developed centres are immune to these accidents?2IAEAOverviewIt should be noted that the i
2、ntent is certainly not to reflect the quoted centres in this presentation in poor lightInstead,the purpose is to draw lessonsIn many cases,the centres have a quality system in placeThe events are reconstructed from information in the public domain,and might differ from actual events due to gaps in t
3、his information.3IAEAOverview1st example:Incorrect manual parameter transfer(UK)2nd example:Reversal of images(USA)3rd example:Inappropriate measuring device(France)4th example:Erroneous calculation for soft wedges(France)5th example:Incorrect IMRT planning(USA)6th example:More information neededNew
4、er examples of accidents in radiotherapy from 2004 to 20074IAEAInternational Atomic Energy Agency1st example:Incorrect manual parameter transfer(UK)IAEA Training CourseIAEABackgroundJanuary 2006 at the Beatson Oncology Centre(BOC)in Glasgow,ScotlandAt the time:Radiotherapy physics staffing levels in
5、 Scotland less than 60%of the recommended level“Glasgow has problems with recruiting physicists,as shown by their high number of vacancies.”The Beatson OncologyCentre in Glasgow6IAEABackgroundTreatment planning at BOC:14.5 whole time equivalent(WTE)staff were available for between 4500 and 5000 new
6、treatment plans per year.When staffing levels were compared with guidelines from IPEM,it was seen that 18 WTE staff would be the recommended level.7IAEABackgroundTreatment planning at BOC:Planning staff members and planning procedures were both categorizedA to C denotes senior to junior staffA to E
7、denotes simple to complex plansThe main duties per staff category is outlined in column 4 Table from:“Report of an investigation by the Inspector appointed by the Scottish Ministers for The Ionising Radiation(Medical Exposures)Regulations 2000”8IAEABackgroundTreatment planning at BOC:Practice prior
8、to 2005 had been to let the treatment planning system(TPS)calculate the Monitor Units(MU)for 1 Gy followed by manual multiplication with the intended dose per fraction for the correct MU-setting to use.9IAEABackgroundTreatment planning at BOC:In May 2005,the Record and Verify(RV)system was upgraded
9、to be a more integrated platform.The centre decided to input the dose per fraction already in the TPS,for most but not all treatment techniques.10IAEAWhat happened?5th January 2006,Lisa Norris,15 years old,started her whole CNS treatment at BOCThe treatment plan was divided into head-fields and lowe
10、r and upper spine-fieldsThis is considered to be a complex treatment plan,performed about six times per year at the BOC.Lisa Norris11IAEAWhat happened?The bulk of the planning was done by“Planner X”in Dec05,a junior planner“Planner X”had not yet been registered internally to be competent to plan who
11、le CNS,or to train on these“Planner X”got initial instructions and the opportunity to be supervised when creating the plan12IAEAWhat happened?Whole CNS plans still went by the“old system”,where TPS calculates MU for 1 Gy with subsequent upscaling for dose per fxA “medulla planning form”was used,whic
12、h is passed to treatment radiographers for final MU calculationsTable from:“Report of an investigation by the Inspector appointed by the Scottish Ministers for The Ionising Radiation(Medical Exposures)Regulations 2000”13IAEAWhat happened?HOWEVER “Planner X”let the TPS calculate the MU for the full d
13、ose per fx not for 1 Gy as intendedSince the dose per fx to the head was 1.67 Gy,the MUs entered in the form were 67%too high for each of the head-fieldsTable from:“Report of an investigation by the Inspector appointed by the Scottish Ministers for The Ionising Radiation(Medical Exposures)Regulation
14、s 2000”14IAEAWhat happened?This error was not found by the more senior planners who checked the planThe radiographer on the unit thus multiplied with the dose per fx a second time2.92 Gy per fx to the headTable from:“Report of an investigation by the Inspector appointed by the Scottish Ministers for
15、 The Ionising Radiation(Medical Exposures)Regulations 2000”15IAEA“Planner X”calculated another plan of the same kind and made the same mistakeThis time,the error was discovered by a senior checker(1st of Feb 06)The same day,the error in calculations for Lisa Norris was also identifiedDiscovery of ac
16、cident16IAEAThe total dose to Lisa Norris from the Right and Left Lateral head fields was 55.5 Gy(19 x 2.92 Gy)She died nine months after the accidentImpact of accident17IAEALessons to learnEnsure that all staffAre properly trained in safety critical proceduresAre included in training programmes and
17、 has supervision as necessary,and that records of training are kept up-to-dateUnderstand their responsibilitiesInclude in the Quality Assurance Program Formal procedures for verifying the risks following the introduction of new technologies and proceduresIndependent MU checking of ALL treatment plan
18、sReview staffing levels and competencies 18IAEAReferencesUnintended overexposure of patient Lisa Norris during radiotherapy treatment at the Beatson Oncology Centre,Glasgow in January 2006.Report of an investigation by the Inspector appointed by the Scottish Ministers for The Ionising Radiation(Medi
19、cal Exposures)Regulations 2000(2006)Cancer in Scotland:Radiotherapy Activity Planning for Scotland 2011 2015.Report of The Radiotherapy Activity Planning Steering Group The Scottish Executive.Edinburgh.(2006)The Glasgow incident a physicists reflections.W.P.M.Mayles.Clin Oncol 19:4-7(2007)Radiothera
20、py near misses,incidents and errors:radiotherapy incident in Glasgow.M.V.Williams.Clin Oncol 19:1-3(2007)19IAEAInternational Atomic Energy Agency2nd example:Reversal of images(USA)IAEA Training CourseIAEAWhat happened?October 2007 at the Karmanos Cancer Center(KCC)in midtown Detroit,Michigan,USAAt t
21、he Gamma Knife treatment facility,a patient was set up for MRI imagingStandard practice is to position the patient“head first”The patient was positioned“head first”,but“feet first”scan technique was chosen on the unitThe KCC in Detroit21IAEAWhat happened?The axial images were therefore reversed left
22、-to-rightThe physicist did not see the mistake when importing images into the TPSThe error resulted in an 18 mm shift of isocentre across the midline of the brainStereotactic treatment(image from KCC)22IAEALessons to learnInclude in the Quality Assurance Program Procedures for verifying left from ri
23、ght in safety critical images,e.g.by using fiducial markersEnsure there are written protocols posted,known and followed,for safety critical procedures23IAEAReferencesGamma knife treatment to wrong side of brain.Event Notification Report 43746.United States Nuclear Regulatory Commission(2007)24IAEAIn
24、ternational Atomic Energy Agency3rd example:Inappropriate measuring device(France)IAEA Training CourseIAEABackgroundReported 2007 at Hpital de Rangueil in Toulouse,FranceIn April 2006,the physicist in the clinic commissioned the new BrainLAB Novalis stereotactic unitThis unit can operate with microM
25、LCs(3 mm leaf-width)or conical standard collimatorsThe Hpital de Rangueil in Toulouse26IAEABackgroundVery small fields can be defined with the microMLCsHigh dose to a 6 x 6 mm field is within capabilityThe TPS requires percent depth doses,beam profiles and relative scatter factors down to this field
26、 sizeCare must be taken when measuring small fields!27IAEAWhat happened?Different measuring devices were used by the physicistA measuring device not suitable for calibrating the smallest microbeams was used“an ionisation chamber of inappropriate dimensions”according to Nuclear Safety Authority(ASN)i
27、nspectors28IAEAWhat happened?The incorrect data was entered into the TPSAll patients treated with micro MLC were planned based on this incorrect dataPatients treated with conical collimator were not affected29IAEABrainLAB discovered that the measurement files did not match up with those at other com
28、parable centres,during a worldwide intercomparison studyIt should be noted that the company does not validate or hold responsibility for local measurements or implementationDiscovery of accident30IAEAImpact of accidentTreatment based on the incorrect data went on for a year(Apr06 Apr07)All patients
29、treated with microMLC were affected(145 of 172 stereotactic patients)The dosimetric impact was evaluated as small in most cases,with 6 patients identified for whom over 5%of the volume of healthy organs may have been affected by dose exceeding limits31IAEALessons to learnEnsure that staffUnderstand
30、the properties and limitations of the equipment they are usingInclude in the Quality Assurance Program Intercomparison with other hospitals,i.e.independent check of new equipment by independent group(using independent equipment)before equipment is clinically used32IAEAReferencesReport concerning the
31、 radiotherapy incident at the university hospital centre(CHU)in Toulouse Rangueil Hospital.ASN Autorit de Sret Nuclaire(2007)33IAEAInternational Atomic Energy Agency4th example:Erroneous calculation for soft wedges(France)IAEA Training CourseIAEABackgroundIn May 2004 at Centre Hospitalier Jean Monne
32、t in Epinal,Franceit was decided to change from static(hard)wedges to dynamic(soft)wedges for prostate cancer patientsIn a country of few Medical Physicists(MP),this facility had a single MP who was also on call in another clinicThe Jean Monnet Hospital in Epinal35IAEABackgroundIn preparation for th
33、e change in treatment technique,two operators(treatment planners?)were given two brief demosThe operators did not have any operating manual in their native language36IAEABackgroundWhen the soft wedges were introduced:The independent MU check in use could not be used anymore(unless modified)The diode
34、s used for independent dose check could not be correctly interpreted anymore37IAEAWhat happened?Treatment planning with soft wedges startedNot all the treatment planners did understand the interface to the planning system 15 30 45 DW 38IAEAWhat happened?Treatment planning with soft wedges startedNot
35、 all the treatment planners did understand the interface to the planning systemSome selected the planning for mechanical wedge when intending dynamic wedge 15 30 45 DW v39IAEAWhat happened?Treatment planning with soft wedges startedNot all the treatment planners did understand the interface to the p
36、lanning systemSome selected the planning for mechanical wedge when intending dynamic wedgeInstead they should have selected Dynamic Wedge 15 30 45 DW v40IAEAWhat happened?Treatment planning with soft wedges startedNot all the treatment planners did understand the interface to the planning systemSome
37、 selected the planning for mechanical wedge when intending dynamic wedgeInstead they should have selected Dynamic Wedgewhich would have let the correct planning tool appear 15 30 45 DW v15 30 45 41IAEAWhat happened?When planning was finished and the isodose distribution approvedthe parameters were m
38、anually transferred to the treatment unitManually transferred MUs would have been calculated for mechanical wedges and would be much greater than what is needed for giving the same dose with dynamic wedges42IAEADetails not clear,BUT:it might have been when MU check software was replaced and updated
39、to be able to handle independent checking of dynamic wedges.Discovery of accident43IAEAImpact of accidentTreatment based on incorrect MUs went on for over a year(6 May 2004 1 Aug 2005)At least 23 patients received overdose(20%or more than intended dose)Between September 2005 and September 2006,four
40、patients died.At least ten patients show severe radiation complications(symptoms such as intense pain,discharges and fistulas)44IAEAInformation following accident15 Sep 2005,two doctors from the clinic passed on information that went to the Regional Dept.of Health and Social Security(DDASS)5 Oct 200
41、5 a meeting was held at DDASS.Decisions were not documented or uniformly interpreted.National authorities in charge were not informed at this stage,but only a full year after the accident(July 2006)45IAEAInformation following accident7 patients were informed during the last quarter of 2005.16 other
42、patients were(wrongly)considered no to be affected.Of these 3 were informed by another doctor than their radiotherapist 1 learnt from a third party person 1 learnt from the press 1 learnt by overhearing a doctor speaking to a colleague 4 were informed by management 2 days before press release 1 died
43、 before being informed46IAEALessons to learnEnsure that staffUnderstand the properties and limitations of the equipment they are usingAre properly trained in safety critical proceduresInclude in the Quality Assurance Program Formal procedures for verifying new technologies and procedures before impl
44、ementationIndependent MU checking of ALL treatment plansIn vivo dosimetryMake sure the clinic has a system in place forInvestigation and reporting of accidentsPatient management and follow up,including communication to patientsInstructions should be in a language that is understood47IAEAReferencesSu
45、mmary of ASN report n 2006 ENSTR 019-IGAS n RM 2007-015P on the Epinal radiotherapy accident.G.Wack,F.Lalande,M.D.Seligman(2007)Accident de radiothrapie pinal.P.J.Compte.Socit Franaise de Physique Mdicale(2006)Lessons from Epinal.D.Ash.Clin Oncol 19:614-615(2007)48IAEAPostscript to accident in Epina
46、lGoing through the records,two further episodes were reported subsequentlyReported in Feb 2007:In the time period 2001-2006,portal imaging was used repeatedly without taking into account the added dose(estimated to have been+8%of total)for 412 patients under medical surveyReported in July 2007:In th
47、e time period 1989-2000,use of an in-house TPS not updated after change in treatment technique,might have led to 300 patients receiving up to 7%added dose.49IAEAInternational Atomic Energy Agency5th example:Incorrect IMRT planning(USA)IAEA Training CourseIAEABackgroundMarch 2005,somewhere in the sta
48、te of New York,USAA patient is due to be treated with IMRT for head and neck cancer(oropharynx)51IAEAWhat happened?March 4 7,2005An IMRT plan is prepared:“1 Oropharyn”.A verification plan is created in the TPS and measurements by Portal Dosimetry(with EPID)confirms correctness.Example of an EPID(Ele
49、ctronic Portal Imaging Device)(Picture:P.Munro)52IAEAWhat happened?March 8,2005The patient begins treatment with the plan“1 Oropharyn”.This treatment is delivered correctly.“Model view”of treatment plan(Picture:VMS)53IAEAWhat happened?March 9-11,2005Fractions#2,3 and 4 are also delivered correctly.V
50、erification images for the kV imaging system are created and added to the plan,now called“1A Oropharyn”.“Model view”of treatment plan(Picture:VMS)54IAEAWhat happened?March 11,2005The physician reviews the case and wants a modified dose distribution(reducing dose to teeth)“1A Oropharyn”is copied and
