1、ISO/ASTM 51261:2013(E)Standard Practice forCalibration of Routine Dosimetry Systems for RadiationProcessing1This standard is issued under the fixed designation ISO/ASTM 51261; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the yea
2、r of last revision.1. Scope1.1 This practice specifies the requirements for calibratingroutine dosimetry systems for use in radiation processing,including establishing measurement traceability and estimatinguncertainty in the measured dose using the calibrated dosim-etry system.NOTE 1Regulations or
3、other directives exist in many countries thatgovern certain radiation processing applications such as sterilization ofhealthcare products and radiation processing of food requiring thatabsorbed-dose measurements be traceable to national or internationalstandards (ISO 11137-1, Refs (1-3)2).1.2 The ab
4、sorbed-dose range covered is up to 1 MGy.1.3 The radiation types covered are photons and electronswith energies from 80 keV to 25 MeV.1.4 This document is one of a set of standards that providesrecommendations for properly implementing dosimetry inradiation processing, and describes a means of achie
5、vingcompliance with the requirements of ASTM E2628 “Practicefor Dosimetry in Radiation Processing” for the calibration ofroutine dosimetry systems. It is intended to be read in conjunc-tion with ASTM E2628 and the relevant ASTM or ISO/ASTMstandard practice for the dosimetry system being calibratedre
6、ferenced in Section 2.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior
7、to use.2. Referenced documents2.1 ASTM Standards:3E170 Terminology Relating to Radiation Measurements andDosimetryE178 Practice for Dealing With Outlying ObservationsE2628 Practice for Dosimetry in Radiation ProcessingE2701 Guide for Performance Characterization of Dosim-eters and Dosimetry Systems
8、for Use in Radiation Pro-cessing2.2 ISO/ASTM Standards:351607 Practice for Use of an Alanine-EPR Dosimetry Sys-tem51707 Guide for Estimating Uncertainties in Dosimetry forRadiation Processing2.3 International Commission on Radiation Units and Mea-surements Reports:4ICRU Report 85a Fundamental Quanti
9、ties and Units forIonizing Radiation2.4 ISO Standards:5ISO 11137-1 Sterilization of health care productsRadiationRequirements for the development, validationand routine control of a sterilization process for medicaldevices2.5 ISO/IEC Standards:517025 General Requirements for the Competence of Testin
10、gand Calibration Laboratories1This guide is under the jurisdiction of ASTM Committee E61 on RadiationProcessing and is the direct responsibility of Subcommittee E61.01 on Dosimetry,and is also under the jurisdiction of ISO/TC 85/WG 3.Current edition approved Aug. 16, 2012. Published April 2013. Orig
11、inallypublished as ASTM E 1261 88. Last previous ASTM edition E 1261 00. ASTME 1261 941was adopted by ISO in 1998 with the intermediate designation ISO15556:1998(E). The present International Standard ISO/ASTM 51261:2013(E) is amajor revision of ISO/ASTM 51261:2002(E), which replaced ISO 15556.2The
12、boldface numbers given in parentheses refer to the bibliography at the endof this guide.3For referenced ASTM and ISO/ASTM standards, visit the ASTM website,www.astm.org, or contact ASTM Customer Service at serviceastm.org. ForAnnual Book of ASTM Standards volume information, refer to the standardsDo
13、cument Summary page on the ASTM website.4Available from International Commission on Radiation Units andMeasurements, 7910 Woodmont Avenue, Suite 800, Bethesda, MD 20814, USA.5Available from International Organization for Standardization (ISO), 1, ch. dela Voie-Creuse, Case postale 56, CH-1211, Genev
14、a 20, Switzerland, http:/www.iso.ch. ISO/ASTM International 2017 All rights reservedThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides an
15、d Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.12.6 Joint Committee for Guides in Metrology (JCGM)Reports:6JCGM 100:2008, GUM 1995, with minor corrections,Evaluation of measurement data Guide to the Expres-sion of Uncertainty in Measurement3. Ter
16、minology3.1 Definitions:3.1.1 approved laboratorylaboratory that is a recognizednational metrology institute; or has been formally accredited toISO/IEC 17025; or has a quality system consistent with therequirements of ISO/IEC 17025.3.1.1.1 DiscussionA recognized national metrology insti-tute or othe
17、r calibration laboratory accredited to ISO/IEC17025 should be used in order to ensure traceability to anational or international standard. A calibration certificateprovided by a laboratory not having formal recognition oraccreditation will not necessarily be proof of traceability to anational or int
18、ernational standard.3.1.2 calibrationset of operations that establish, underspecified conditions, the relationship between values of quan-tities indicated by a measuring instrument or measuringsystem, or values represented by a material measure or areference material, and the corresponding values re
19、alized bystandards.3.1.3 calibration curveexpression of the relation betweenindication and the corresponding measured quantity value.3.1.4 charged-particle equilibrium (referred to as electronequilibrium in the case of electrons set in motion by photonbeam irradiation of a material)condition in whic
20、h the kineticenergy of charged particles (or electrons), excluding rest mass,entering an infinitesimal volume of the irradiated materialequals the kinetic energy of charged particles (or electrons)emerging from it.3.1.5 dosimeter batchquantity of dosimeters made from aspecific mass of material with
21、uniform composition, fabricatedin a single production run under controlled, consistentconditions, and having a unique identification code.3.1.6 dosimeter stockpart of a dosimeter batch held by theuser.3.1.7 dosimetry systemsystem used for measuring ab-sorbed dose, consisting of dosimeters, measureme
22、nt instru-ments and their associated reference standards, and proceduresfor the systems use.3.1.8 electron equilibriumcharged particle equilibrium forelectrons. (See charged-particle equilibrium.)3.1.9 influence quantityquantity that is not the measurandbut that affects the result of the measurement
23、.3.1.10 in-situ/in-plant calibrationcalibration where thedosimeter irradiation is performed in the place of use of theroutine dosimeters.3.1.10.1 DiscussionIn-situ/in-plant calibration of dosim-etry systems refers to irradiation of dosimeters along withreference or transfer standard dosimeters, unde
24、r operatingconditions that are representative of the routine processingenvironment, for the purpose of developing a calibration curvefor the routine dosimetry systems.3.1.11 measurandspecific quantity subject to measure-ment.3.1.12 measurement management systemset of inter-related or interacting ele
25、ments necessary to achieve metrologi-cal confirmation and continual control of measurement pro-cesses.3.1.13 primary standard dosimetry systemdosimetry sys-tem that is designated or widely acknowledged as having thehighest metrological qualities and whose value is acceptedwithout reference to other
26、standards of the same quantity.3.1.14 reference standard dosimetry systemdosimetrysystem, generally having the highest metrological qualityavailable at a given location or in a given organization, fromwhich measurements made there are derived.3.1.15 routine dosimetry systemdosimetry system cali-brat
27、ed against a reference standard dosimetry system and usedfor routine absorbed dose measurements, including dose map-ping and process monitoring.3.1.16 traceabilityproperty of the result of a measurementor the value of a standard whereby it can be related to statedreferences, usually national or inte
28、rnational standards, throughan unbroken chain of comparisons all having stated uncertain-ties.3.1.16.1 DiscussionMeasurement traceability is a require-ment of any measurement management system (see AnnexA4).3.1.17 transfer standard dosimetry systemdosimetry sys-tem used as an intermediary to calibra
29、te other dosimetrysystems.3.1.18 type I dosimeterdosimeter of high metrologicalquality, the response of which is affected by individual influ-ence quantities in a well-defined way that can be expressed interms of independent correction factors.3.1.19 type II dosimeterdosimeter, the response of which
30、is affected by influence quantities in a complex way that cannotpractically be expressed in terms of independent correctionfactors.3.1.20 uncertainty (of measurement)parameter associatedwith the result of a measurement that characterizes the disper-sion of the values that could reasonably be attribu
31、ted to themeasurand or derived quantity.3.1.21 uncertainty budgetquantitative analysis of thecomponent terms contributing to the uncertainty of ameasurement, including their statistical distribution, math-ematical manipulation and summation.3.2 validation (of a process)establishment of documentedevi
32、dence, which provides a high degree of assurance that aspecified process will consistently produce a product meetingits predetermined specifications and quality attributes.6Document produced by Working Group 1 of the Joint Committee for Guides inMetrology (JCGM/WG 1). Available free of charge at the
33、 BIPM website (http:/www.bipm.org).ISO/ASTM 51261:2013(E)2 ISO/ASTM International 2017 All rights reserved 3.3 verificationconfirmation by examination of objectiveevidence that specified requirements have been met.3.3.1 DiscussionIn the case of measuring equipment, theresult of verification leads to
34、 a decision either to restore toservice or to perform adjustments, repair, downgrade, ordeclare obsolete. In all cases it is required that a written traceof the verification performed be kept on the instrumentsindividual record.3.4 Definitions of other terms used in this standard thatpertain to radi
35、ation measurement and dosimetry may be foundin ASTM Terminology E170. Definitions in ASTM Terminol-ogy E170 are compatible with ICRU Report 85a; thatdocument, therefore, may be used as an alternative reference.4. Significance and use4.1 Ionizing radiation is used to produce various desiredeffects in
36、 products. Examples of applications include thesterilization of medical products, microbial reduction, modifi-cation of polymers and electronic devices, and curing of inks,coatings, and adhesives (4).4.2 Absorbed-dose measurements, with statistical controlsand documentation, are necessary to ensure
37、that productsreceive the desired absorbed dose. These controls include aprogram that addresses requirements for calibration of routinedosimetry system.4.3 A routine dosimetry system calibration procedure asdescribed in this document provides the user with a dosimetrysystem whose dose measurements ar
38、e traceable to national orinternational standards for the conditions of use (see AnnexA4). The dosimetry system calibration is part of the usersmeasurement management system.5. Dosimeter system calibration overview5.1 Calibration of a routine dosimetry system consists of thefollowing:5.1.1 Selection
39、 of the calibration dosimeters from the userstock (see Section 8).5.1.2 Irradiation of the calibration dosimeters (see 9.1 and9.2).5.1.3 Calibration and/or performance verification of mea-surement instruments (see Section 7).5.1.4 Measurement of the calibration dosimeters response(see 9.1.6 and 9.2.
40、5.1).5.1.5 Analysis of the calibration dosimeter response data(see 9.1.7 and 9.2.6).5.1.6 Verification of the calibration curve for conditions ofuse, if appropriate (see 9.1.8 and Note 2).5.1.7 Estimation of the combined uncertainty for the condi-tions of use (see 9.1.10 and 9.2.7).5.1.8 Verificatio
41、n of the calibration curve at a time otherthan calibration for assessment of continuing validity of thecalibration curve (see 9.1.11, 9.2.9, and Note 2).NOTE 2Calibration verification is conducted as part of the calibrationwhen the calibration irradiation conditions are different from the condi-tion
42、s of use (5.1.6). Calibration verification is also conducted betweencalibrations to ensure continued suitability of the calibration curve for theconditions of use (5.1.8).5.2 Calibration Irradiation MethodsThere are two meth-ods for irradiating dosimeters for calibration:5.2.1 Calibration irradiatio
43、ns performed at an approvedlaboratory followed by a calibration verification exercise.5.2.2 In-situ/in-plant calibration irradiations of routine do-simeters along with transfer standard dosimeters issued andanalyzed by an approved laboratory.NOTE 3Valid in-situ/in-plant calibration irradiations resu
44、lt in a cali-bration curve generated under conditions that are representative of theroutine processing environment.An in-situ/in-plant calibration may not bevalid or may require calibration verification if the calibration conditionscan not be maintained during routine use. For example, the calibrati
45、onirradiations are carried out as a single exposure, but the dosimeter is usedfor dose measurement of fractionated irradiations.5.3 Uncertainties:5.3.1 All measurements of absorbed dose need to be accom-panied by an estimate of uncertainty (see ISO/ASTM 51707,Refs (5,6) and GUM).5.3.2 All components
46、 of uncertainty should be included inthe estimate, including those arising from calibration, dosim-eter reproducibility, instrument stability and the effect ofinfluence quantities.Afull quantitative analysis of componentsof uncertainty is referred to as an uncertainty budget and isoften presented in
47、 the form of a table. Typically, the uncer-tainty budget will identify all significant components of uncer-tainty together with their methods of estimation, statisticaldistributions and magnitudes.5.3.3 Examples of components of uncertainty in the dosim-etry system calibration include inherent varia
48、tion in dosimeterresponse, uncertainty in the calibration irradiation dose, uncer-tainty in the calibration curve fit and uncertainty in dosimeterresponse correction parameters such as dosimeter thickness,dosimeter mass, unirradiated response and irradiation tempera-ture.5.3.4 Additional components
49、of uncertainty might be pres-ent when the conditions of use are different than the conditionsof calibration. In these instances, a calibration verification isconducted to quantify a component of uncertainty to accountfor these differences (see 9.1.8 and 9.2.9).6. Requirements for a routine dosimetry systemcalibration6.1 Dosimetry system calibration shall be conducted foreach new dosimeter batch.NOTE 4The response of different dosimeter stocks purchased atdiffer
