ANSI ISO ASTM 51275-2013 Standard Practice for Use of a Radiochromic Film Dosimetry System.pdf

1、ISO/ASTM 51275:2013(E)Standard Practice forUse of a Radiochromic Film Dosimetry System1This standard is issued under the fixed designation ISO/ASTM 51275; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision.1.

2、 Scope1.1 This is a practice for using radiochromic film dosimetrysystems to measure absorbed dose in materials irradiated byphotons or electrons in terms of absorbed dose to water.Radiochromic film dosimetry systems are generally used asroutine dosimetry systems.1.2 The radiochromic film dosimeter

3、is classified as a TypeII dosimeter on the basis of the complex effect of influencequantities. See ASTM Practice E2628.1.3 This document is one of a set of standards that providesrecommendations for properly implementing dosimetry inradiation processing, and describes a means of achievingcompliance

4、with the requirements of ASTM E2628 “Practicefor Dosimetry in Radiation Processing” for a radiochromic filmdosimetry system. It is intended to be read in conjunction withASTM E2628.1.4 This practice covers the use of radiochromic filmdosimetry systems under the following conditions:1.4.1 The absorbe

5、d dose range is 1 Gy to 150 kGy.1.4.2 The absorbed dose rate is110-2to11013Gys-1(1-4).21.4.3 The photon energy range is 0.1 to 50 MeV.1.4.4 The electron energy range is 70 keV to 50 MeV.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is th

6、eresponsibility of the user of this 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:3E170 Terminology Relating to Radiation Measurements andDosimetryE275 Practice for Desc

7、ribing and Measuring Performance ofUltraviolet and Visible SpectrophotometersE2628 Practice for Dosimetry in Radiation ProcessingE2701 Guide for Performance Characterization of Dosim-eters and Dosimetry Systems for Use in Radiation Pro-cessing2.2 ISO/ASTM Standards:351261 Practice for Calibration of

8、 Routine Dosimetry Sys-tems for Radiation Processing51707 Guide for Estimating Uncertainties in Dosimetry forRadiation Processing2.3 International Commission on Radiation Units and Mea-surements (ICRU) Reports:4ICRU Report 85a Fundamental Quantities and Units forIonizing RadiationICRU Report 80 Dosi

9、metry Systems for Use in RadiationProcessing2.4 Joint Committee for Guides in Metrology (JCGM)Reports:JCGM 100:2008, GUM 1995, with minor corrections,Evaluation of measurement data Guide to the Expres-sion of Uncertainty in Measurement5JCGM 200:2008, VIM, International vocabulary of metrol-ogy Basis

10、 and general concepts and associated terms63. Terminology3.1 Definitions:1This guide is under the jurisdiction of ASTM Committee E61 on RadiationProcessing and is the direct responsibility of Subcommittee E61.02 on DosimetrySystems, and is also under the jurisdiction of ISO/TC 85/WG 3.Current editio

11、n approved April 9, 2013. Published June 2013. Originallypublished as ASTM E 127588. Last previous ASTM edition E 1275981. ASTME 127593 was adopted by ISO in 1998 with the intermediate designation ISO15557:1998(E). The present International Standard ISO/ASTM 51275:2013(E)replaces ISO 15557 and is a

12、major revision of the last previous edition ISO/ASTM51275:2004(E).2The boldface numbers in parentheses refer to the bibliography at the end of thisstandard.3For referenced ASTM and ISO/ASTM standards, visit the ASTM website,www.astm.org, or contact ASTM Customer Service at serviceastm.org. ForAnnual

13、 Book of ASTM Standards volume information, refer to the standardsDocument Summary page on the ASTM website.4Available from the International Commission on Radiation Units andMeasurements, 7910 Woodmont Ave., suite 800, Bethesda, MD 20814, USA.5Document produced by Working Group 1 of the Joint Commi

14、ttee for Guides inMetrology (JCGM/WG 1). Available free of charge at the BIPM website (http:/www.bipm.org).6Document produced by Working Group 2 of the Joint Committee for Guides inMetrology (JCGM/WG 2). Available free of charge at the BIPM website (http:/www.bipm.org). ISO/ASTM International 2017 A

15、ll 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 and Recommendations issued by the World Trade Organization Technical

16、 Barriers to Trade (TBT) Committee.13.1.1 calibration curveexpression of the relation betweenindication and corresponding measured quantity value. (VIM)3.1.1.1 DiscussionIn radiation processing dosimetrystandards, the term dosimeter response is generally usedrather than indication.3.1.2 dosimeterdev

17、ice having a reproducible, measurableresponse to radiation that can be used to measure the absorbeddose in a given system.3.1.3 dosimeter batchquantity of dosimeters made from aspecific mass of material with uniform composition, fabricatedin a single production run under controlled, consistentcondit

18、ions, and having a unique identification code.3.1.4 dosimetry responsereproducible, quantifiable effectproduced in the dosimeter by ionizing radiation.3.1.4.1 DiscussionFor radiochromic film dosimeters, theabsorbance, specific absorbance or specific net absorbance isthe dosimeter response.3.1.5 dosi

19、metry stockpart of a dosimeter batch held by theuser.3.1.6 measurement management systema set of interre-lated or interacting elements necessary to achieve metrologicalconfirmation and continual control of measurement processes.3.1.7 radiochromic film dosimeterspecially prepared filmcontaining ingre

20、dients that undergo change in optical absor-bance under ionizing radiation, which can be related toabsorbed dose to water.3.1.8 reference standard dosimetry systemdosimetrysystem, generally having the highest metrological qualityavailable at a given location or in a given organization, fromwhich mea

21、surements made there are derived.3.1.9 responsesee dosimeter response.3.1.10 routine dosimetry systemdosimetry system cali-brated against a reference standard dosimetry system and usedfor routine absorbed dose measurements, including dose map-ping and process monitoring.3.1.11 specific absorbance (k

22、)optical absorbance, A,ataselected wavelength , divided by the optical path length, d:k 5 A/D (1)3.1.12 specific net absorbance (k)net absorbance, A,at a selected wavelength, , divided by the optical pathlength,d, through the dosimeter material as follows:k 5A/D (2)3.2 Definitions of other terms use

23、d in this practice thatpertain to radiation measurement and dosimetry may be foundin ASTM Terminology E170. Definitions in E170 are compat-ible with ICRU Report 85a; that document, therefore, may beused as an alternative reference.4. Significance and use4.1 The radiochromic film dosimetry system pro

24、vides ameans for measuring absorbed dose based on radiation-inducedchange in color using spectrophotometers, densitometers orscanned images.4.2 Radiochromic film dosimetry systems are commonlyused in industrial radiation processing, for example in thesterilization of medical devices and the irradiat

25、ion of foods.5. Overview5.1 Radiochromic film dosimeters are manufactured byvarious methods to produce freestanding or coated films, whichare flexible and transparent. They are generally supplied assmall squares, strips, or long rolls or sheets that can be cut intoa convenient size for dosimetry pur

26、poses. The response of thedosimeters may be influenced by water content, irradiationtemperature, post-irradiation time to measurement, and otherpotential influence quantities that need to be taken intoaccount. Many commercially available dosimeters are suppliedin light- and vapor-tight packages, whi

27、ch effectively protectagainst light and changes in ambient humidity. The dosimetersshould be calibrated under irradiation conditions that aresimilar to those in which they will be used.5.2 Ionizing radiation induces chemical reactions in thematerial, which create or enhance absorption bands in thevi

28、sible or ultraviolet regions, or both, of the optical spectrum.Absorbance determined at appropriate wavelengths withinthese radiation-induced absorption bands is quantitatively re-lated to the absorbed dose. ICRU Report 80 provides technicalinformation and historical development of the radiochromicf

29、ilm dosimetry systems in current use.5.3 The radiation-induced change in absorbance of theradiochromic film depends on the wavelength of the lightwhich is used to make the measurement.6. Influence quantities6.1 Factors other than absorbed dose which influence thedosimeter response are referred to as

30、 influence quantities.Examples of such factors are temperature and dose rate. SeeASTM Guide E2701. See Refs (2-14) for examples of the typesand magnitudes of the effects.6.2 Pre-Irradiation Conditions:6.2.1 Dosimeter Conditioning and PackagingDosimetersmay be conditioned by the manufacturer to optim

31、ize watercontent in the film, and then sealed in vapor and light tightpouches to maintain that condition.6.2.2 Time since ManufactureThe shelf-life of some typesof radiochromic film dosimeters has been shown to exceed nineyears. However, it is recommended that users carry outperformance verification

32、 of pre-irradiation absorbance andpost-irradiation response stability over the useful life of thedosimeter batch.6.2.3 TemperatureExposure to extreme temperature dur-ing shipment and storage at the users facility might affectdosimeter response. The manufacturer should be consulted forspecific recomm

33、endations for dosimeter shipment and storage.6.2.4 Relative HumidityDosimeters may be packaged sothey are not affected by environmental changes in humidity;dosimeters without protective packaging might be affected.The manufacturer should be consulted for specific recommen-dations for dosimeter shipm

34、ent and storage.6.2.5 Exposure to LightDosimeters may be packaged sothey are not affected by exposure to light; dosimeters withoutISO/ASTM 51275:2013(E)2 ISO/ASTM International 2017 All rights reserved protective packaging might be affected. The manufacturershould be consulted for specific recommend

35、ations for dosim-eter shipment and storage.6.3 Conditions During Irradiation:6.3.1 Irradiation TemperatureIrradiation temperature isexpected to influence dosimeter response. It is recommended tocalibrate the dosimetry system under the conditions of use(in-plant calibration) in order to mitigate the

36、effect of tempera-ture on dosimeter response.6.3.2 Absorbed-dose RateAbsorbed-dose rate might influ-ence dosimeter response. It is recommended to calibrate thedosimetry system under the conditions of use (in-plant calibra-tion) in order to mitigate any possible effect of dose rate ondosimeter respon

37、se.6.3.3 Dose FractionationDose fractionation might influ-ence dosimeter response. It is recommended to calibrate thedosimetry system under the conditions of use (in-plant calibra-tion) in order to mitigate any possible effect of dose fraction-ation.6.3.4 Relative HumidityFor some dosimeters, the am

38、ountof water in the dosimeter is known to influence its response.For dosimeters used outside manufacturers sealed packaging,it is recommended to calibrate the dosimetry system under theconditions of use (in-plant calibration) in order to mitigate anypossible effect of variations in the amount of wat

39、er in thedosimeter and hence its response.6.3.5 Exposure to LightDosimeters may be packaged sothey are not affected by exposure to light; dosimeters withoutprotective packaging might be affected.6.3.6 Radiation EnergyThe response of dosimeters hasbeen demonstrated to be independent of energy. Howeve

40、r,when electron energy is low enough to result in a dose gradientthrough the thickness of the dosimeter, difficulties in interpre-tation of the measured response may result (15).NOTE 1At low energies the thickness of the packaging material mightgive rise to measurement errors.6.4 Post-Irradiation Co

41、nditions:6.4.1 TimeDosimeters may take significant time for theabsorbance to stabilize after irradiation (10-12, 16 and 17).Apost irradiation heat-treatment process may stabilize the absor-bance sooner. Dosimeter manufacturer should be consulted forspecific recommendation for post-irradiation heat t

42、reatment.NOTE 2The response of FWT-60 and B3 dosimeters can be stabilizedby a post-irradiation heat treatment.6.4.2 TemperatureStorage temperature after irradiationmight influence dosimeter response. Dosimeter manufacturershould be consulted for specific recommendation for storage ofirradiated dosim

43、eters.6.4.3 Relative HumidityWater content in dosimeter afterirradiation might influence dosimeter response. Dosimetermanufacturer should be consulted for specific recommendationfor storage of irradiated dosimeters.6.4.4 Exposure to LightDosimeters may be packaged sothey are not affected by exposure

44、 to light; dosimeters withoutprotective packaging might be affected.6.5 Response Measurement Conditions:6.5.1 Requirements for post irradiation conditions apply toconditions of measurement.NOTE 3Light used for measurement of dosimeter response mightcontain a UV component that can affect dosimeter re

45、sponse.7. Dosimetry system and its verification7.1 Components of the Radiochromic Film DosimetrySystemThe following are components of radiochromic filmdosimetry systems:7.1.1 Radiochromic Film DosimetersThe film may beprovided in bulk or in pouches of one or more dosimeters. Apouch provides humidity

46、 and light protection.7.1.2 Measurement InstrumentsFor each instrument usedto measure dosimeter response, determine and establish thespecific measurement settings capable of providing highlyreproducible results over the required dose range. For example,use the peak absorbance wavelength for a specif

47、ic dosimeter tooptimize measurement reproducibility. Some dosimeters mayrequire use of an off-peak wavelength to extend the usable doserange. Examples of appropriate analysis wavelengths for spe-cific dosimetry systems are provided by the manufacturer andin Refs (3-10, 16-21). Depending on the speci

48、fic dosimetrysystem, the response may be absorbance, change inabsorbance, specific absorbance or specific net absorbance.7.1.2.1 Spectrophotometer (or an equivalent instrument),with appropriate traceable calibration standards.NOTE 4Select a spectrophotometer capable of satisfying specifiedprecision

49、and dose range requirements. For example, in thin filmdosimetry, the spectral bandwidth setting must be appropriate for a givendosimeter thickness in order to avoid introducing optical interferencefringes that adversely affect measurement reproducibility and can severelylimit the lower end of achievable dose range.7.1.2.2 Densitometer, with appropriate traceable calibrationstandards.7.1.2.3 Film Image Scanner, with appropriate traceablecalibrat