1、ISO/ASTM 51702:2013(E)Standard Practice forDosimetry in a Gamma Facility for Radiation Processing1This standard is issued under the fixed designation ISO/ASTM 51702; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last
2、revision.1. Scope1.1 This practice outlines the installation qualification pro-gram for an irradiator and the dosimetric procedures to befollowed during operational qualification, performancequalification, and routine processing in facilities that processproducts with ionizing radiation from radionu
3、clide gammasources to ensure that product has been treated within apredetermined range of absorbed dose. Other procedures re-lated to operational qualification, performance qualification,and routine processing that may influence absorbed dose in theproduct are also discussed.NOTE 1Dosimetry is only
4、one component of a total quality assuranceprogram for adherence to good manufacturing practices used in radiationprocessing applications.NOTE 2ISO/ASTM Practices 51818 and 51649 describe dosimetricprocedures for low and high enery electron beam facilities for radiationprocessing and ISO/ASTM Practic
5、e 51608 describes procedures for X-ray(bremsstrahlung) facilities for radiation processing.1.2 For the radiation sterilization of health care products,see ISO 11137-1. In those areas covered by ISO 11137-1, thatstandard takes precedence.1.3 This document is one of a set of standards that providesrec
6、ommendations for properly implementing and utilizingdosimetry in radiation processing. It is intended to be read inconjunction with ASTM Practice E2628.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of thi
7、s standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced documents2.1 ASTM Standards:2E170 Terminology Relating to Radiation Measurements andDosimetryE2232 Guide for Selection and Use of Mathematical Meth-o
8、ds for Calculating Absorbed Dose in Radiation Process-ing ApplicationsE2303 Guide for Absorbed-Dose Mapping in RadiationProcessing FacilitiesE2628 Practice for Dosimetry in Radiation ProcessingE2701 Guide for Performance Characterization of Dosim-eters and Dosimetry Systems for Use in Radiation Pro-
9、cessing2.2 ISO/ASTM Standards:251261 Practice for Calibration of Routine Dosimetry Sys-tems for Radiation Processing51539 Guide for Use of Radiation-Sensitive Indicators51608 Practice for Dosimetry in an X-Ray (Bremsstrahlung)Facility for Radiation Processing51649 Practice for Dosimetry in an Electr
10、on Beam Facilityfor Radiation Processing at Energies Between 300 KeVand 25 KeV51707 Guide for Estimating Uncertainties in Dosimetry forRadiation Processing51818 Practice for Dosimetry in an Electron Beam Facilityfor Radiation Processing at Energies Between 80 and 300keV2.3 International Commission o
11、n Radiation Units and Mea-surements (ICRU) Reports:3ICRU Report 85a Fundamental Quantities and Units forIonizing Radiation2.4 ISO Standards:4ISO 11137-1 Sterilization of health care products Radia-tion Part 1: Requirements for development, validation,1This practice is under the jurisdiction of ASTM
12、Committee E61 on RadiationProcessing and is the direct responsibility of Subcommittee E61.03 on DosimetryApplication, and is also under the jurisdiction of ISO/TC 85/WG 3.Current edition approved Dec. 26, 2012. Published April 2013. Originallypublished as E 1702-95. Last previous ASTM edition E 1702
13、00. ASTME 1702951was adopted by ISO in 1998 with the intermediate designation ISO15571:1998(E). The present International Standard ISO/ASTM 51702:2013(E)replaces ISO 15571 and is a major revision of the last previous edition ISO/ASTM517022004(E).2For referenced ASTM and ISO/ASTM standards, visit the
14、 ASTM website,www.astm.org, or contact ASTM Customer Service at serviceastm.org. ForAnnual Book of ASTM Standards volume information, refer to the standardsDocument Summary page on the ASTM website.3Available from the International Commission on Radiation Units andMeasurements, 7910 Woodmont Ave., S
15、uite 800, Bethesda, MD 20814, USA.4Available from International Organization for Standardization (ISO), 1 rue deVaremb, Case postale 56, CH-1211, Geneva 20, Switzerland, http:/www.iso.ch. ISO/ASTM International 2017 All rights reservedThis international standard was developed in accordance with inte
16、rnationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1and routine control of a sterilization process
17、for medicaldevices2.5 Joint Committee for Guides in Metrology (JCGM)Reports:5JCGM 100:2008, GUM 1995, with minor corrections,Evaluation of measurement data Guide to the Expres-sion of Uncertainty in Measurement3. Terminology3.1 Definitions:3.1.1 absorbed dose, Dquantity of ionizing radiation en-ergy
18、 imparted per unit mass of a specified material. The SI unitof absorbed dose is the gray (Gy), where 1 gray is equivalentto the absorption of 1 joule per kilogram of the specifiedmaterial (1 Gy = 1 J/kg). The mathematical relationship is thequotient of d by dm, where d is the mean incremental energy
19、imparted by ionizing radiation to matter of incremental massdm (see ICRU Report 85a).D 5d/dm (1)3.1.2 absorbed-dose mappingmeasurement of absorbeddose within an irradiation product to produce a one-, two- orthree-dimensional distribution of absorbed dose, thus renderinga map of absorbed-dose values.
20、3.1.3 calibration curveexpression of the relation betweenindication and corresponding measured quantity value.3.1.3.1 DiscussionIn radiation processing standards, theterm “dosimeter response” is generally used for “indication.”3.1.4 compensating dummySee simulated product.3.1.5 dosimeter responserep
21、roducible, quantifiable radia-tion effect produced in the dosimeter by ionizing radiation.3.1.6 dosimeter setone or more dosimeters used to mea-sure the absorbed dose at a location and whose average readingis used as the absorbed-dose measurement at that location.3.1.7 dosimetry systemsystem used fo
22、r absorbed dose,consisting of dosimeters, measurement instruments and theirassociated reference standards, and procedures for the systemsuse.3.1.8 installation qualification (IQ)process of obtainingand documenting evidence that equipment has been providedand installed in accordance with specificatio
23、ns.3.1.9 irradiation containerholder in which product isplaced during the irradiation process.3.1.9.1 Discussion“Irradiation container” is often referredto simply as “container” and can be a carrier, cart, tray, productcarton, pallet, product package or other holder.3.1.10 operational qualification
24、(OQ)process of obtainingand documenting evidence that installed equipment operateswithin predetermined limits when used in accordance with itsoperational procedures.3.1.11 performance qualification (PQ)process of obtain-ing and documenting evidence that the equipment, as installedand operated in acc
25、ordance with operational procedures, con-sistently performs in accordance with predetermined criteriaand thereby yields product meeting its specification.3.1.12 production run (for continuous-flow and shuffle-dwell irradiations)series of irradiation containers consistingof materials or products havi
26、ng similar radiation-absorptioncharacteristics that are irradiated sequentially to a specifiedrange of absorbed dose.3.1.13 simulated productmass of material with absorptionand scattering properties similar to those of the product,material, or substance to be irradiated.3.1.13.1 DiscussionSimulated
27、product is used during irra-diator characterization as a substitute for the actual product,material or substance to be irradiated. When used in routineproduction runs in order to compensate for the absence ofproduct, simulated product is sometimes referred to as com-pensating dummy. When used for ab
28、sorbed-dose mapping,simulated product is sometimes referred to as phantom mate-rial.3.1.14 timer settingdefined time interval during whichproduct is exposed to radiation.3.1.14.1 DiscussionFor a shuffle-dwell irradiator the timersetting is the time interval from the start of one shuffle-dwellcycle t
29、o the start of the next shuffle-dwell cycle. For astationary irradiator, the timer setting is the total irradiationtime.3.2 Definitions of other terms used in this standard thatpertain to radiation measurement and dosimetry may be foundin ASTM Terminology E170. Definitions in E170 are compat-ible wi
30、th ICRU Report 85a; ICRU Report 85a, therefore, maybe used as an alternative reference.4. Significance and use4.1 Various products and materials routinely are irradiatedat predetermined doses in gamma irradiation facilities toreduce their microbial population or to modify their character-istics. Dos
31、imetry requirements may vary depending upon theirradiation application and end use of the product. Someexamples of irradiation applications where dosimetry may beused are:4.1.1 Sterilization of medical devices,4.1.2 Treatment of food for the purpose of parasite andpathogen control, insect disinfesta
32、tion, and shelf life extension,4.1.3 Disinfection of consumer products,4.1.4 Cross-linking or degradation of polymers andelastomers,4.1.5 Polymerization of monomers and grafting of mono-mers onto polymers,4.1.6 Enhancement of color in gemstones and othermaterials,4.1.7 Modification of characteristic
33、s of semiconductordevices, and4.1.8 Research on materials effects.NOTE 3Dosimetry is required for regulated irradiation processes suchas sterilization of medical devices and the treatment of food. It may be lessimportant for other industrial processes, for example, polymermodification, which can be
34、evaluated by changes in the physical andchemical properties of the irradiated materials.5Document produced by Working Group 1 of the Joint Committee for Guides inMetrology (JCGM/WG 1). Available free of charge at the BIPM website (http:/www.bipm.org).ISO/ASTM 51702:2013(E)2 ISO/ASTM International 20
35、17 All rights reserved 4.2 An irradiation process usually requires a minimumabsorbed dose to achieve the intended effect. There also may bea maximum absorbed dose that the product can tolerate andstill meet its functional or regulatory specifications. Dosimetryis essential to the irradiation process
36、 since it is used todetermine both of these limits and to confirm that the productis routinely irradiated within these limits.4.3 The absorbed-dose distribution within the product de-pends on the overall product dimensions and mass, irradiationgeometry, and source activity distribution.4.4 Before an
37、 irradiation facility can be used, it must bequalified to determine its effectiveness in reproducibly deliv-ering known, controllable absorbed doses. This involves test-ing the process equipment, calibrating the equipment anddosimetry system, and characterizing the magnitude, distribu-tion and repro
38、ducibility of the absorbed dose delivered by theirradiator for a range of product densities.4.5 To ensure consistent and reproducible dose delivery in aqualified process, routine process control requires documentedproduct handling procedures before and after irradiation, con-sistent product loading
39、configuration, control and monitoringof critical process parameters, routine product dosimetry anddocumentation of the required activities.5. Radiation source characteristics5.1 The radiation source used in a facility considered in thispractice consists of sealed elements of60Co or137Cs which aretyp
40、ically linear rods or “pencils” arranged in one or moreplanar or cylindrical arrays.5.2 A cobalt-60 source emits photons with energies ofapproximately 1.17 and 1.33 MeV in nearly equal proportions.A cesium-137 source emits photons with energies of approxi-mately 0.662 MeV (1).65.3 The radioactive de
41、cay half-lives for60Co and137Cs areregularly reviewed and updated. The most recent publicationby the National Institute of Standards and Technology gavevalues of 1925.20 (60.25) days for60Co and 11018.3 (69.5)days for137Cs (2).5.4 Between source replenishments, removals, orredistributions, the varia
42、tion in the source output is solely dueto the steady reduction in the activity caused by the radioactivedecay.6. Types of facilities6.1 The design of an irradiator affects the delivery ofabsorbed dose to a product. Therefore, the irradiator designshould be considered when performing the absorbed-dos
43、emeasurements described in Sections 9 through 11.6.2 Products may be moved to locations where the irradia-tion will take place, either while the source is fully shielded(batch operation) or while the source is exposed (continuousoperation).6.3 Products may be transported past the source at a uniform
44、and controlled speed (continuous conveyance), may undergo aseries of shuffle-dwell cycles during which product movementsare followed by periods of time during which the irradiationcontainer is stationary (shuffle-dwell), or may be irradiated atfixed locations (stationary).6.3.1 The desired absorbed
45、dose for the product is obtainedby controlling by the conveyor speed (continuous conveyance)or the timer setting (shuffle-dwell or stationary).6.3.2 For many commercial irradiators, the irradiation con-tainers move in one or more parallel rows on each side of avertical rectangular source array. The
46、irradiation containersmay move past a source array in a configuration in which thesource either extends above and below the irradiation container(source overlap) or the irradiation container extends above andbelow the source (product overlap). In the latter configuration,the irradiation container mo
47、ves past the source at two or morelevels.6.3.2.1 In bulk-flow irradiators, products such as grain orflour flow in loose form past the source. The desired absorbeddose is obtained by controlling the flow rate.6.4 Because of mechanical speed limitations, various tech-niques may be used to reduce the a
48、bsorbed-dose rates for lowabsorbed-dose applications. These techniques include usingonly a portion of the source (for example, raising only one ofseveral source racks to the irradiation position), usingattenuators, and irradiating at greater distances from the source.7. Dosimetry system calibration7
49、.1 The dosimetry system shall be calibrated in accordancewith Practice 51261, and the users procedures, which shouldspecify details of the calibration process and quality assurancerequirements.7.2 The dosimetry system calibration is part of a measure-ment management system.8. Installation qualification8.1 ObjectiveThe purpose of an installation qualificationprogram is to demonstrate that the irradiator with its associatedprocessing equipment and measurement instrume
