BS ISO 21439-2009 Clinical dosimetry - Beta radiation sources for brachytherapy《临床放射量测定 短程治疗用β辐射源》.pdf

1、BS ISO21439:2009ICS 11.040.50; 17.240NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDClinical dosimetry Beta radiation sourcesfor brachytherapyThis British Standardwas published under theauthority of the StandardsPolicy and StrategyCommittee on 28 February2009 B

2、SI 2009ISBN 978 0 580 56286 0Amendments/corrigenda issued since publicationDate CommentsBS ISO 21439:2009National forewordThis British Standard is the UK implementation of ISO 21439:2009.The UK participation in its preparation was entrusted to TechnicalCommittee NCE/2, Radiation protection and measu

3、rement.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisionsof a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunityf

4、rom legal obligations.BS ISO 21439:2009Reference numberISO 21439:2009(E)ISO 2009INTERNATIONAL STANDARD ISO21439First edition2009-02-15Clinical dosimetry Beta radiation sources for brachytherapy Dosimtrie clinique Sources de radiation bta pour curiethrapie BS ISO 21439:2009ISO 21439:2009(E) PDF discl

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9、mber body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2009 All rights reservedBS ISO 21439:2009ISO 21439:2009(E) ISO 2009 All rights reserv

10、ed iiiContents Page Foreword .v Introductionvi 1 Scope1 2 Normative references1 3 Terms and definitions .2 4 Beta radiation sources and source data.8 4.1 Ophthalmic and dural brachytherapy sources.8 4.2 Intravascular brachytherapy sources .9 4.3 Characteristics of radionuclides9 4.4 Source specifica

11、tion .9 5 Dose calculation parameters and formalisms11 5.1 General .11 5.2 Radiation-field parameterization12 5.3 Radial dose profile 13 5.4 Normalization of relative-dose data for seed sources.14 5.5 Adaptation of the TG-43/60 formalism for a long beta radiation line source16 5.6 Reference data set

12、s.17 5.7 Parameters for source uniformity characterization.17 6 Calibration and traceability 19 6.1 Measurand19 6.2 Traceability.19 6.3 Reference point .19 6.4 Primary standards .19 6.5 Secondary standards19 6.6 Transfer standards 19 6.7 Calibration of therapeutic beta radiation sources .20 7 Dose m

13、easurements in-phantom and measurement corrections20 7.1 Measurements in water or a water-equivalent phantom .20 7.2 Detectors for beta radiation21 7.3 Conversion of absorbed dose in solid phantoms to absorbed dose to water22 7.4 Effective point of measurement in the detector.24 8 Theoretical modell

14、ing .25 8.1 Point-dose kernels 25 8.2 Monte Carlo simulation.26 9 Uncertainties in source calibrations .28 9.1 General .28 9.2 Uncertainty of primary standards28 9.3 Uncertainty of secondary standards .28 9.4 Uncertainty of transfer standards28 9.5 Relationship of dosimetry uncertainty to positional

15、 error29 9.6 Uncertainty in theoretical modeling 29 10 Treatment planning and reporting.30 10.1 General .30 10.2 General aspects of treatment planning.30 10.3 Documentation in ophthalmic brachytherapy30 10.4 Uncertainty of the dose delivered in ophthalmic brachytherapy .30 10.5 Documentation in intr

16、avascular brachytherapy.31 BS ISO 21439:2009ISO 21439:2009(E) iv ISO 2009 All rights reserved10.6 Reporting uncertainties in intravascular brachytherapy.33 11 Clinical quality control 33 11.1 Acceptance tests .33 11.2 Constancy checks .37 Annex A (normative) Reference data 38 Annex B (informative) R

17、eference data sheet examples 43 Annex C (informative) Primary standards for beta radiation dosimetry52 Annex D (informative) Detectors and phantom materials for clinical dosimetry of beta radiation brachytherapy sources .58 Annex E (informative) Monte Carlo calculations68 Annex F (informative) Treat

18、ment planning .77 Bibliography 82 BS ISO 21439:2009ISO 21439:2009(E) ISO 2009 All rights reserved vForeword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally c

19、arried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the wor

20、k. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare Inter

21、national Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of th

22、e elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 21439 was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommittee SC 2, Radiation protection. BS ISO 21439:2009ISO 21439:2009(E) vi IS

23、O 2009 All rights reservedIntroduction Clinical dosimetry covers the methods by which values of the relevant physical quantity, absorbed dose to water, can be measured at a given point by the use of calibrated instruments in a clinical setting. The application of beta radiation sources for brachythe

24、rapy requires new and skilled methods for adequate clinical dosimetry necessitated by the short range of the beta radiation. This causes large dose-rate gradients around beta radiation sources, and hence it is necessary that the detector volumes for absorbed-dose measurements be extremely small. Thi

25、s leads to the requirement for highly specialized detectors and calibration techniques, and it is necessary to scrutinize closely every calibration obtained in one beta radiation field and determine if it is applicable in another field. It is necessary that an appropriate quality system be implement

26、ed and maintained in the hospital for clinical beta radiation source dosimetry. It is the responsibility of the medical physicist to carry out testing and calibration activities for any source in such a way as to meet the requirements for adequate dosimetry. This International Standard gives guidanc

27、e on how to satisfy these needs. BS ISO 21439:2009INTERNATIONAL STANDARD ISO 21439:2009(E) ISO 2009 All rights reserved 1Clinical dosimetry Beta radiation sources for brachytherapy 1 Scope This International Standard specifies methods for the determination of absorbed-dose distributions in water or

28、tissue that are required prior to initiating procedures for the application of beta radiation in ophthalmic tumour and intravascular brachytherapy1, 2, 3. Recommendations are given for beta radiation source calibration, dosimetry measurements, dose calculation, dosimetric quality assurance, as well

29、as for beta radiation brachytherapy treatment planning. Guidance is also given for estimating the uncertainty of the absorbed dose to water. This International Standard is applicable to “sealed” radioactive sources, such as plane and concave surface sources, source trains of single seeds, line sourc

30、es, and shell and volume sources, for which only the beta radiation emitted is of therapeutic relevance. The standardization of procedures in clinical dosimetry described in this International Standard serves as a basis for the reliable application of beta radiation brachytherapy. The specific dosim

31、etric methods described in this International Standard apply to sources for the curative treatment of ophthalmic disease, for intravascular brachytherapy treatment, for overcoming the problem of restenosis and for other clinical applications using beta radiation. This International Standard is geare

32、d towards organizations wishing to establish reference methods in dosimetry aiming at clinical demands for an appropriately small uncertainty of the delivered dose. This International Standard does not exclude the possibility that there can be other methods leading to the same or smaller measurement

33、 uncertainties. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the cited document (including any amendments) applies. ISO/IEC Guide 9

34、8-3, Uncertainty in measurement Part 3: Guide to the expression of uncertainty in measurement (GUM:1995) ISO/IEC Guide 99, International vocabulary of metrology Basic and general concepts and associated terms (VIM) ISO 6980-2, Nuclear energy Reference beta particle radiation Part 2: Calibration fund

35、amentals related to basic quantities characterizing the radiation field ICRU Report 51, Quantities and Units in Radiation Protection Dosimetry BS ISO 21439:2009ISO 21439:2009(E) 2 ISO 2009 All rights reserved3 Terms and definitions For the purposes of this document, the terms and definitions given i

36、n ICRU Report 51, ISO Guide 99 and ISO 6980-2, and the following apply. 3.1 absorbed dose D quotient of d by dm, where d is the mean energy imparted by ionizing radiation to matter of mass dm, as given by Equation (1): ddDm= (1) NOTE The absorbed dose is designated in units of joules per kilogram, w

37、ith the special name of gray (Gy). 3.2 absorbed dose to water Dwquotient of d by dm, where d is the mean energy imparted to water by ionizing radiation to a medium of mass dm, as given by Equation (2): ddwDm= (2) NOTE The absorbed dose to water is designated in units of joules per kilogram, with the

38、 special name of gray (Gy). 3.3 acceptance test contractual test carried out by the user on receipt of a new instrument or source(s) in order to verify compliance with contractual specifications NOTE 1 An acceptance test of an instrument is carried out after new equipment has been installed, or majo

39、r modifications have been made to existing equipment. NOTE 2 An acceptance test of a source is carried out on each source before being put into service for the first time. If a consignment contains more than one source, it is carried out on all sources of a particular type. 3.4 active source length

40、ASL length of the source over which the absorbed dose rate at a defined distance from the source axis is within a specified ratio of the maximum absorbed dose rate at this distance 3.5 afterloading automatically or manually controlled transfer of one or more sealed radioactive sources between a stor

41、age container and pre-positioned source applicators for brachytherapy BS ISO 21439:2009ISO 21439:2009(E) ISO 2009 All rights reserved 33.6 average beta energy Eavequotient of beta energy averaged over the distribution, E, of the beta particle fluence with respect to energy as given by Equation (3):

42、maxmaxE0aveE0()ddEEE EEEE=(3) where E= d/dE 3.7 brachytherapy intracavitary, interstitial, superficial (including ophthalmic), or intraluminal (e.g. intravascular) radiotherapy in the immediate vicinity of one or more sealed or unsealed radioactive sources 3.8 calibration set of operations that esta

43、blish, under specific conditions, the relationship between values of a quantity and the corresponding values traceable to primary standards NOTE 1 For an instrument, a calibration establishes, under specific conditions, the relationship between values of a quantity indicated by a measuring instrumen

44、t or measuring system and the corresponding values realized from the standards. NOTE 2 For a source, a calibration establishes, under specific conditions, the value of a quantity produced by the source. 3.9 clinical target volume CTV gross tumour or target volume (GTV) with the addition of a margin

45、that accounts for cells that are clinically suspected but have unproven involvement NOTE In malignant disease, e.g. ophthalmic tumours, these oncological safety margins account for subclinical disease. In restenosis treatment, the CTV includes the full interventional length (IL) of the vessel with a

46、ll vessel wall layers and with the addition of proximal and distal safety margins to include all tissue possibly injured during the interventional process. 3.10 detector test source radiation source used for the determination of the long-term stability of a radiation detector 3.11 dosimeter beta rad

47、iation therapy equipment that uses detectors for the measurement of absorbed dose, or absorbed dose rate, in beta radiation fields as used in radiation therapy NOTE A radiotherapy dosimeter contains the following components: one or more detector assemblies, a measuring assembly (including possibly a

48、 separate display device), one or more detector test sources (optional) and one or more phantoms (optional). 3.12 dwell time time a radioactive source or source train remains at a selected treatment position BS ISO 21439:2009ISO 21439:2009(E) 4 ISO 2009 All rights reserved3.13 effective point of mea

49、surement Peffpoint at which the absorbed dose rate in an undisturbed medium is determined from the detector signal 3.14 extrapolation chamber ionization chamber capable of having a collection volume that is continuously variable to a vanishingly small value by changing the separation of the electrodes, which allows the user to extrapolate the measured ionization density to zero collecting volume NOTE The extrapolation chamber serves as a primary standard, under proper conditions of use (see Annex C). 3.15 flue