PREVENTIONOFACCIDENTALEXPOSUREIN…在事故預(yù)防…課件

1、Module 1.2: BSS appendix 2 (medical exposure)IAEA Training Course第1頁(yè)，共45頁(yè)。BSS Appendix IIBSS Appendix II addresses:Responsibilities of registrants, licensees, and medical practitionersJustification of medical exposuresOptimization of protection for medical exposuresGuidance levels for diagnostic exp

2、osuresDose constraints for volunteersMaximum patient activity at time of dischargeInvestigation of accidental medical exposures and incidentsMaintenance of records2Prevention of accidental exposure in radiotherapy第2頁(yè)，共45頁(yè)。BSS Appendix IIBSS Appendix II addresses:Responsibilities of registrants, lice

3、nsees, and medical practitionersJustification of medical exposuresOptimization of protection for medical exposuresGuidance levels for diagnostic exposuresDose constraints for volunteersMaximum patient activity at time of dischargeInvestigation of accidental medical exposures and incidentsMaintenance

4、 of records3Prevention of accidental exposure in radiotherapy第3頁(yè)，共45頁(yè)。ResponsibilitiesRegistrants and Licensees shall ensure that:Exposures are given only when prescribed by a medical practitionerOverall patient protection be assigned to medical practitionersSufficient number of trained medical and

5、paramedical personnel are available4Prevention of accidental exposure in radiotherapy第4頁(yè)，共45頁(yè)。ResponsibilitiesRegistrants and Licensees shall ensure that:For radiotherapy, the calibration, dosimetry and quality assurance be performed by or under the supervision of a qualified expert in radiotherapy

6、physicsTraining criteria be specified or be subject to approval, as appropriate, by the Regulatory Authority in consultation with relevant professional bodies5Prevention of accidental exposure in radiotherapy第5頁(yè)，共45頁(yè)。ResponsibilitiesComment: In radiotherapy practice Radiotherapy is multidisciplinary

7、 in nature - a variety of professionals are involved.This includes professional groups such as medical physicists, radiotherapy technicians, dosimetrists and engineers specialized in radiotherapy equipment as well as oncology and patient support staff such as oncology nurses, dieticians, social work

8、ers and other allied health professionals.In regard to all physical aspects of the radiation delivery the medical physicist (BSS: “qualified expert in radiotherapy physics”) carries the ultimate responsibility6Prevention of accidental exposure in radiotherapy第6頁(yè)，共45頁(yè)。ResponsibilitiesMedical practiti

9、oners shall promptly inform the registrant or licensee of any deficiencies or needs regarding compliance with the Standards with respect to protection and safety of patients and shall take such actions as may be appropriate to ensure the protection and safety of patients7Prevention of accidental exp

10、osure in radiotherapy第7頁(yè)，共45頁(yè)。BSS Appendix IIBSS Appendix II addresses:Responsibilities of registrants, licensees, and medical practitionersJustification of medical exposuresOptimization of protection for medical exposuresGuidance levels for diagnostic exposuresDose constraints for volunteersMaximum

11、 patient activity at time of dischargeInvestigation of accidental medical exposures and incidentsMaintenance of records8Prevention of accidental exposure in radiotherapy第8頁(yè)，共45頁(yè)。JustificationJustification of medical exposure:The benefit has to balance the risk, taking into account the benefits and r

12、isks of available alternative techniques that do not involve medical exposure Guidelines (e.g. WHO) should be considered9Prevention of accidental exposure in radiotherapy第9頁(yè)，共45頁(yè)。JustificationJustification of medical exposure:Radiological exams should have clinical indications, provide information o

13、n health, or be otherwise justifiedScreening is justified only if the expected advantages for the individuals examined or for the population as a whole are sufficient to compensate for the economic and social costs, including the radiation detriment10Prevention of accidental exposure in radiotherapy

14、第10頁(yè)，共45頁(yè)。JustificationJustification of medical exposure:Exposure of humans for medical research shall be:in accordance with the Helsinki Conventionevaluated by an Ethical Review CommitteeExamination as part of theft detection purposes is deemed not justified, but if conducted is considered non-medi

15、cal exposure11Prevention of accidental exposure in radiotherapy第11頁(yè)，共45頁(yè)。BSS Appendix IIBSS Appendix II addresses:Responsibilities of registrants, licensees, and medical practitionersJustification of medical exposuresOptimization of protection for medical exposuresGuidance levels for diagnostic expo

16、suresDose constraints for volunteersMaximum patient activity at time of dischargeInvestigation of accidental medical exposures and incidentsMaintenance of records12Prevention of accidental exposure in radiotherapy第12頁(yè)，共45頁(yè)。OptimizationSubsections of “Optimization of protection” deal with requirement

17、s addressing:Design of equipment and facilitiesOperation of facilities for diagnosis and treatmentCalibration of sources and equipmentClinical dosimetryQuality assurance13Prevention of accidental exposure in radiotherapy第13頁(yè)，共45頁(yè)。Optimization 1: DesignSources for medical exposure shall meet requirem

18、ents elsewhere in BSS, and shall be designed so that:failure of single component is detected promptly to reduce risk of unintended exposurelikelihood of human error in the delivery of unplanned medical exposure is minimized14Prevention of accidental exposure in radiotherapy第14頁(yè)，共45頁(yè)。Optimization 1:

19、DesignRegistrants and licensees shall:use information from supplier to anticipate errorstake reasonable measures to prevent errorsemploy qualified personnelestablish procedures for calibration, QA, protectionprovide proper training and regular retrainingtake measures to reduce consequences of errors

20、develop contingency plans to respond to errors, display plans, and conduct drills15Prevention of accidental exposure in radiotherapy第15頁(yè)，共45頁(yè)。Optimization 1: DesignRegistrants and licensees in collaboration with suppliers shall ensure in relation to equipment (sources):conformation to ISO / IEC stan

21、dardsThere should be awareness in developing countries that they have the power to require compliance by suppliers and to make use of acceptance tests, which are universally shared by manufacturers16Prevention of accidental exposure in radiotherapy第16頁(yè)，共45頁(yè)。Optimization 1: DesignRegistrants and lice

22、nsees in collaboration with suppliers shall ensure in relation to equipment (sources):performance specifications, operating, maintenance and safety instructions provided in a major world language understandable to the user and translated into local languages when appropriateconsole displays paramete

23、rs and instructions in a major world language acceptable to the user17Prevention of accidental exposure in radiotherapy第17頁(yè)，共45頁(yè)。Optimization 1: DesignRegistrants and licensees in collaboration with suppliers shall ensure in relation to equipment (sources):beam control mechanism be fail-safe and cle

24、arly displayedexposure be limited to area being examinedradiation field be as uniform as practicalexposure rates outside area being examined be kept as low as reasonably achievable18Prevention of accidental exposure in radiotherapy第18頁(yè)，共45頁(yè)。Optimization 1: DesignRegistrants and licensees in collabor

25、ation with suppliers shall ensure in relation to diagnostic equipment (sources):generator design facilitates keeping of medical exposures as low as reasonably achievable consistent with obtaining adequate diagnostic information operating parameters are clearly and accurately displayedexposures are t

26、erminated automatically (time / mAs / dose)fluoroscopy requires constant pressure on a switch, and indications are provided of elapsed time or surface dose19Prevention of accidental exposure in radiotherapy第19頁(yè)，共45頁(yè)。Optimization 1: DesignRegistrants and licensees in collaboration with suppliers shal

27、l ensure in relation to therapeutic equipment (sources):operating parameters can be selected and are displayed clearly, accurately and unambiguouslysealed sources return to safe in event of failurehigh-energy equipment:have two independent fail-to-safety mechanisms to terminate irradiationallow oper

28、ation only in conditions selected at control panel20Prevention of accidental exposure in radiotherapy第20頁(yè)，共45頁(yè)。Optimization 1: DesignRegistrants and licensees in collaboration with suppliers shall ensure in relation to therapeutic equipment (sources):bypassing of interlocks can be performed only by

29、maintenance personnel using proper keys or codestele- and brachytherapy sources comply with requirements for “sealed sources”monitoring equipment gives warning of unusual situation21Prevention of accidental exposure in radiotherapy第21頁(yè)，共45頁(yè)。Optimization 2: OperationRegistrants and licensees shall en

30、sure in relation to diagnostic exposure operation that medical practitioners who prescribe or conduct exams:ensure that appropriate equipment is usedensure that the exposure of patients be the minimum necessary to achieve the required diagnostic objective, taking into account norms of acceptable ima

31、ge quality established by appropriate professional bodies and relevant guidance levels for medical exposureconsider previous exams to avoid unnecessary exposure22Prevention of accidental exposure in radiotherapy第22頁(yè)，共45頁(yè)。Optimization 2: OperationRegistrants and licensees shall ensure in relation to

32、diagnostic exposure operation that:technologists select the relevant parameters so that their combination produces minimum patient exposure fulfilling the clinical purpose of the examinationportable/mobile equipment be used only when necessaryexaminations that might expose an embryo or fetus be avoi

33、ded if possibleshielding of radiosensitive organs be provided when appropriate23Prevention of accidental exposure in radiotherapy第23頁(yè)，共45頁(yè)。Optimization 2: OperationRegistrants and licensees shall ensure in relation to therapeutic exposure operation that:exposure of normal tissue during radiotherapy

34、be kept as low as reasonably achievable consistent with delivering the required dose to the planning target volume, and organ shielding be used when feasible and appropriateradiotherapeutic procedures causing exposure of the abdomen or pelvis of women who are pregnant or likely to be pregnant be avo

35、ided unless there are strong clinical indications patients be informed of possible risks24Prevention of accidental exposure in radiotherapy第24頁(yè)，共45頁(yè)。Optimization 3: CalibrationRegistrants and licensees shall ensure that:the calibration of sources used for medical exposure shall be traceable to a Sta

36、ndards Dosimetry Laboratorythe calibration of radiotherapy equipment shall be in conformance with a protocol (such as IAEA TRS-277 based on air kerma standards)*at the moment of issuing the BSS the TRS 398 (based on absorbed-dose-to water standards) was not yet issued25Prevention of accidental expos

37、ure in radiotherapy第25頁(yè)，共45頁(yè)。Optimization 3: CalibrationRegistrants and licensees shall ensure that:sealed sources be calibrated in terms of activity, RAKR, or absorbed dose: medium, distance and date specifiedunsealed sources be calibrated in terms of activity at time of usecalibration be part of c

38、ommissioning of treatment unit, following service work, and at intervals approved by Regulatory Authority26Prevention of accidental exposure in radiotherapy第26頁(yè)，共45頁(yè)。Optimization 4: Clinical DosimetryRegistrants and licensees shall ensure these items are determined and documented:radiological examin

39、ations: representative dose valuesexternal beam radiotherapy: min. and max. dose to PTV as well as dose to relevant point (center) and other points deemed significant brachytherapy: absorbed dose at relevant pointstreatment with unsealed sources: representative dose all radiotherapeutic treatments:

40、dose to relevant organs27Prevention of accidental exposure in radiotherapy第27頁(yè)，共45頁(yè)。Optimization 4: Clinical DosimetryRegistrants and licensees shall also ensure that, within acceptable ranges of good practice and equipment performance:the prescribed dose at the prescribed beam quality is delivered

41、to the PTVdoses to other tissues and organs are minimized28Prevention of accidental exposure in radiotherapy第28頁(yè)，共45頁(yè)。Optimization 5: Quality AssuranceRegistrants and licensees shall establish a comprehensive QA programme which shall include:measurements of physical parameters of radiation generator

42、s, imaging devices and irradiation installations at commissioning and periodically thereafterverification of appropriate physical and clinical factors used in patient diagnosis and treatment29Prevention of accidental exposure in radiotherapy第29頁(yè)，共45頁(yè)。Optimization 5: Quality AssuranceRegistrants and

43、licensees shall establish a comprehensive QA programme which shall include:written records of relevant procedures and resultsverification of calibration and operating conditions of dosimetric and monitoring equipmentas far as possible, regular and independent quality audit reviews of the QA programm

44、e for RT procedures30Prevention of accidental exposure in radiotherapy第30頁(yè)，共45頁(yè)。BSS Appendix IIBSS Appendix II addresses:Responsibilities of registrants, licensees, and medical practitionersJustification of medical exposuresOptimization of protection for medical exposuresGuidance levels for diagnost

45、ic exposuresDose constraints for volunteersMaximum patient activity at time of dischargeInvestigation of accidental medical exposures and incidentsMaintenance of records31Prevention of accidental exposure in radiotherapy第31頁(yè)，共45頁(yè)。Guidance LevelsRegistrants and licensees should ensure guidance levels

46、 are determined and implemented so that:corrective actions be taken if doses fall substantially below guidance levels and the exposure does not yield the intended benefit of exam or treatmentreviews be considered if doses exceed guidance levels as an input to ensuring optimized protection of patient

47、s 32Prevention of accidental exposure in radiotherapy第32頁(yè)，共45頁(yè)。Guidance LevelsFor diagnostic and nuclear medicine exams, guidance levels should be derived from surveys of broad spectrum of exams, and consider entrance doses, beam areas, and radionuclide activitiesIf such surveys are not available, r

48、efer to guidance levels in BSS Schedule III for a guide to performance of equipment33Prevention of accidental exposure in radiotherapy第33頁(yè)，共45頁(yè)。BSS Appendix IIBSS Appendix II addresses:Responsibilities of registrants, licensees, and medical practitionersJustification of medical exposuresOptimization

49、 of protection for medical exposuresGuidance levels for diagnostic exposuresDose constraints for volunteersMaximum patient activity at time of dischargeInvestigation of accidental medical exposures and incidentsMaintenance of records34Prevention of accidental exposure in radiotherapy第34頁(yè)，共45頁(yè)。Dose C

50、onstraintsWhen individuals are to be exposed for research purposes, without likelihood of direct benefit, the Ethical Review Committee shall specify dose constraints to be followed.35Prevention of accidental exposure in radiotherapy第35頁(yè)，共45頁(yè)。Dose ConstraintsRegistrants and licensees shall constrain

51、any dose to individuals incurred knowingly while voluntarily helping (other than in their occupation) in the care, support or comfort of patients undergoing medical diagnosis or treatment, and to visitors to patients who have received therapeutic amounts of radionuclides or who are being treated wit

52、h brachytherapy sources, to a level not exceeding that specified in Schedule II of the BSS.36Prevention of accidental exposure in radiotherapy第36頁(yè)，共45頁(yè)。BSS Appendix IIBSS Appendix II addresses:Responsibilities of registrants, licensees, and medical practitionersJustification of medical exposuresOpti

53、mization of protection for medical exposuresGuidance levels for diagnostic exposuresDose constraints for volunteersMaximum patient activity at time of dischargeInvestigation of accidental medical exposures and incidentsMaintenance of records37Prevention of accidental exposure in radiotherapy第37頁(yè)，共45

54、頁(yè)。Max patient activity at dischargePatients who have received therapeutic procedures with sealed or unsealed radionuclides shall not be discharged until the activity within the body falls below the level specified in Schedule III of the BSS.38Prevention of accidental exposure in radiotherapy第38頁(yè)，共45

55、頁(yè)。BSS Appendix IIBSS Appendix II addresses:Responsibilities of registrants, licensees, and medical practitionersJustification of medical exposuresOptimization of protection for medical exposuresGuidance levels for diagnostic exposuresDose constraints for volunteersMaximum patient activity at time of

56、 dischargeInvestigation of accidental medical exposures and incidentsMaintenance of records39Prevention of accidental exposure in radiotherapy第39頁(yè)，共45頁(yè)。Investigation of accidental medical exposuresRegistrants and licensees shall promptly investigate:therapeutic treatment to wrong patient, wrong tiss

57、ue, with wrong pharmaceutical, or with dose or dose fractionation differing substantially from the values prescribed by the medical practitioner or which may lead to undue acute secondary effects diagnostic exposure significantly greater than intended or repeated so as to exceed guidance levelsequipment failure, accident, error or mishap with potential for causing patient exposure significantly different from that intended40Prevention of accidental exposure in radiotherapy第40頁(yè)，共45頁(yè)。Investigation of accidental medical exposuresIf investigation is required, registrants shall:calc