1、Designation: E2303 11An American National StandardStandard Guide forAbsorbed-Dose Mapping in Radiation Processing Facilities1This standard is issued under the fixed designation E2303; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、 the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This document provides guidance in determiningabsorbed-dose distributions (mapping) in products, material
3、sor substances irradiated in gamma, X-ray (bremsstrahlung) andelectron beam facilities.NOTE 1For irradiation of food and the radiation sterilization of healthcare products, other specific ISO and ISO/ASTM standards containingdose mapping requirements exist. For food irradiation, see ISO/ASTM51204, P
4、ractice for Dosimetry in Gamma Irradiation Facilities for FoodProcessing and ISO/ASTM 51431, Practice for Dosimetry in ElectronBeam and X-Ray (Bremsstrahlung) Irradiation Facilities for Food Pro-cessing. For the radiation sterilization of health care products, seeISO 11137-1, Sterilization of Health
5、 Care Products Radiation Part 1:Requirements for Development, Validation and Routine Control of aSterilization Process for Medical Devices. In those areas covered byISO 11137-1, that standard takes precedence. ISO/ASTM 51608, Practicefor Dosimetry in an X-ray (Bremsstrahlung) Facility for RadiationP
6、rocessing, ISO/ASTM 51649, Practice for Dosimetry in an ElectronBeam Facility for Radiation Processing at Energies between 300 keV and25 Mev, ISO/ASTM 51702, Practice for Dosimetry in a Gamma Irradia-tion Facility for Radiation Processing, and ISO/ASTM 51818, Practice forDosimetry in an Electron Bea
7、m Facility for Radiation Processing atEnergies Between 80 and 300 KeV also contain dose mapping require-ments.1.2 This guide is one of a set of standards that providesrecommendations for properly implementing dosimetry inradiation processing. it is intended to be read in conjunctionwith ASTM Practic
8、e E2628.1.3 Methods of analyzing the dose map data are described.Examples are provided of statistical methods that may be usedto analyze dose map data.1.4 Dose mapping for bulk flow processing and fluidstreams is not discussed.1.5 Dosimetry is only one component of a total qualityprogram for an irra
9、diation facility. Other controls besidesdosimetry may be required for specific applications such asmedical device sterilization and food preservation.1.6 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
10、standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory requirements prior to use.2. Referenced Documents2.1 ASTM Standards:2E170 Terminology Relating to Radiation Measurements andDosimetryE178 Practice for Dealing With Outlying ObservationsE2232
11、 Guide for Selection and Use of Mathematical Meth-ods for CalculatingAbsorbed Dose in Radiation ProcessingApplicationsE2628 Practice for Dosimetry in Radiation Processing2.2 ISO/ASTM Standards:2ISO/ASTM 51204 Practice for Dosimetry in Gamma Irra-diation Facilities for Food ProcessingISO/ASTM 51261 G
12、uide for Selection and Calibration ofDosimetry Systems for Radiation ProcessingISO/ASTM 51431 Practice for Dosimetry in Electron Beamand X-Ray (Bremsstrahlung) Irradiation Facilities forFood ProcessingISO/ASTM 51608 Practice for Dosimetry in an X-ray(Bremsstrahlung) Facility for Radiation Processing
13、ISO/ASTM 51649 Practice for Dosimetry in an ElectronBeam Facility for Radiation Processing at Energies be-tween 300 keV and 25 MeVISO/ASTM 51702 Practice for Dosimetry in a GammaIrradiation Facility for Radiation ProcessingISO/ASTM 51707 Guide for Estimating Uncertainties inDosimetry for Radiation P
14、rocessingISO/ASTM 51818 Practice for Dosimetry in an ElectronBeam Facility for Radiation Processing at Energies be-tween 80 and 300 keV2.3 International Commission on Radiation Units andMeasurements Reports:3ICRU Report 60 Fundamental Quantities and Units forIonizing Radiation1This guide is under th
15、e jurisdiction of ASTM Committee E10 on NuclearTechnology and Applications and is the direct responsibility of SubcommitteeE10.01 on Radiation Processing: Dosimetry and Applications.Current edition approved July 1, 2011. Published August 2011. Originallyapproved in 2003. Last previous edition approv
16、ed in 2003 as E2303-03. DOI:10.1520/E2303-11.2For 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 standardsDocument Summary page on the ASTM website.3Av
17、ailable from International Commission on Radiation Units and Measure-ments, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.ICRU Report 80 Dosimetry Systemes for Use in RadiationProce
18、ssing2.4 International Organization for Standardization:4ISO 11137-1 Sterilization of health care products Radia-tion Part 1: Requirements for development, validation,and routine control of a sterilization process for medicaldevicesGUM Guide to the Expression of Uncertainty in Measure-ment, 1995, IS
19、BN 92-6710188-9VIM International Vocabulary of Basic and General Termsin Metrology3. Terminology3.1 Definitions:3.1.1 absorbed-dose mappingmeasurement of absorbeddose within an irradiated product to produce a one-, two- orthree-dimensional distribution of absorbed dose, thus renderinga map of absorb
20、ed-dose values.3.1.1.1 DiscussionFor a process load, such a dose map isobtained using dosimeters placed at specified locations withinthe process load.3.1.2 calibration curve (VIM:2008)expression of the re-lation between indication and corresponding measured quantityvalue.3.1.2.1 DiscussionIn radiati
21、on processing standards, theterm “dosimeter response” is generally used for “indication.”3.1.3 dose map, dose mappingsee absorbed-dose map-ping.3.1.4 dose uniformity ratioratio of the maximum to theminimum absorbed dose within the irradiated product.3.1.4.1 DiscussionThe concept is also referred to
22、as themax/min dose ratio. Product generally refers to the “processload.”3.1.5 dose zonea volume or discrete point(s) within aprocess load that receives the same absorbed dose within thestatistical uncertainty of the irradiation process and absorbed-dose measurement(s).3.1.6 installation qualificatio
23、n (IQ)process of obtainingand documenting evidence that equipment has been providedand installed in accordance with its specification.3.1.7 irradiation containerholder in which process load istransported through the irradiator.3.1.7.1 Discussion“Irradiation container” is often referredto simply as “
24、container” and can be a carrier, cart, try, productcarton, pallet, product package or other holder.3.1.8 operational qualification (OQ)process of obtainingand documenting evidence that installed equipment operateswithin predetermined limits when used in accordance with itsoperational procedures.3.1.
25、9 performance qualification (PQ)process of obtainingand documenting evidence that the equipment, as installed andoperated in accordance with operational procedures, consis-tently performs in accordance with predetermined criteria andthereby yields product meeting its specification.3.1.10 process loa
26、da volume of material with a specifiedproduct loading configuration irradiated as a single entity.3.1.11 processing categorygroup of different product thatcan be processed together.3.1.11.1 DiscussionProcessing categories can be basedon, for instance, composition, density or dose requirements.3.1.12
27、 reference materialhomogeneous material ofknown radiation absorption and scattering properties used toestablish characteristics of the irradiation process, such as scanuniformity, depth-dose distribution, throughput rate, and repro-ducibility of dose delivery.3.1.13 routine monitoring positionpositi
28、on where ab-sorbed dose is monitored during routine processing to ensurethat the product is receiving the absorbed dose specified for theprocess.3.1.13.1 DiscussionThis position may be a location ofminimum or maximum dose in the process load or it may be analternate convenient location in, on or nea
29、r the process loadwhere the relationship of the dose at this position with theminimum and maximum dose has been established.3.1.14 simulated productmaterial with attenuation andscattering properties similar to those of the product, material orsubstance to be irradiated.3.1.14.1 DiscussionSimulated p
30、roduct is used during ir-radiator 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 abs
31、orbed-dose mapping,simulated product is sometimes referred to as phantom mate-rial.3.2 Definitions of other terms used in this standard thatpertain to radiation measurement and dosimetry may be foundin Terminology E170. Definitions in E170 are compatible withICRU Report 60; that document, therefore,
32、 may be used as analternative reference.4. Significance and Use4.1 This guide is one of a set of guides and practices thatprovide recommendations for properly implementing dosim-etry in radiation processing. In order to understand andeffectively use this and other dosimetry standards, considerfirst
33、“Practice for Dosimetry in Radiation Processing,” ASTMPractice E2628, which describes the basic requirements thatapply when making absorbed dose measurements in accor-dance with theASTM E10.01 series of dosimetry standards. Inaddition, ASTM Practice E2628 provides guidance on theselection of dosimet
34、ry systems and directs the user to otherstandards that provide information on individual dosimetrysystems, calibration methods, uncertainty estimation and radia-tion processing applications.4.2 Radiation processing is carried out under fixed pathconditions where (a) a process load is automatically m
35、ovedthrough the radiation field by mechanical means or (b)aprocess load is irradiated statically by manually placing prod-uct at predetermined positions before the process is started. Inboth cases the process is controlled in such a manner that theprocess load position(s) and orientation(s) are repr
36、oduciblewithin specified limits.4Available from International Organization for Standardization (ISO), 1 rue deVaremb, Case postale 56, CH-1211, Geneva 20, Switzerland.E2303 112NOTE 2Static irradiation encompasses irradiation of the process loadusing either manual rotation, no rotation or automated r
37、otation.4.3 Some radiation processing facilities that utilize a fixedconveyor path for routine processing may also characterize aregion within the radiation field for static radiation processing,sometimes referred to as “Off Carrier” processing.4.4 Many radiation processing applications require a mi
38、ni-mum absorbed dose (to achieve a desired effect or to fulfill alegal requirement), and a maximum dose that can be tolerated(while the product, material or substance still meets functionalspecifications or to fulfill a legal requirement).4.5 Dose mapping is used to:4.5.1 Characterize the radiation
39、process and assess thereproducibility of absorbed-dose values, which may be used aspart of operational qualification and performance qualification.4.5.2 Determine the spatial distribution of absorbed dosesand the zone(s) of maximum and minimum absorbed dosesthroughout a process load, which may consi
40、st of an actual orsimulated product.4.5.3 Establish the relationship between the dose at aroutine monitoring position and the dose within the minimumand maximum dose zones established for a process load.4.5.4 Verify mathematical dose calculation methods. SeeASTM Guide E2232.4.5.5 Determine the effec
41、t of process interruptions on thedistribution of absorbed dose and the magnitude of the mini-mum and maximum doses.4.5.6 Assess the impact on the distribution of absorbed doseand the magnitude of the minimum and maximum dosesresulting from the transition from one process load to anotherwhere changes
42、, for example, in product density or productloading pattern may occur.5. Prerequisites5.1 Prerequisites to Dose Mapping: Installation Qualifica-tion and Dosimetry System Calibration:5.1.1 Prior to performing dose mapping for irradiator op-erational qualification (OQ) and performance qualification(PQ
43、), confirm that installation qualification (IQ) is complete.5.1.1.1 For electron beam and X-ray irradiation facilities,IQ includes dosimetric testing to confirm the characteristics ofthe beam (electron energy, average beam current, and ifapplicable, scan width and scan uniformity). Refer to ISO/ASTM
44、 51431, 51608, 51818, 51649 and ISO 11137-1.5.1.1.2 For gamma irradiation facilities, dosimetric testingis not required during IQ; however, the activity of the sourceand location of the individual components of the source shouldbe confirmed and documented. Refer to ISO/ASTM 51204,51702 and ISO 11137
45、-1.5.1.2 Select an appropriate dosimetry system(s) for the dosemapping exercises. See 6.2.4.1 and ASTM Practice E2628 forguidance.5.2 Calibration of the Dosimetry System:5.2.1 Prior to use, the dosimetry system (consisting of aspecific batch of dosimeters and specific measurement instru-ments) shall
46、 be calibrated in accordance with the usersdocumented procedure that specifies details of the calibrationprocess and quality assurance requirements. Calibration meth-ods are described in ISO/ASTM 51261.NOTE 3A generic dosimetry system calibration may be used forrelative dose measurement applications
47、.5.2.2 For the calibration of the instruments, and for theverification of instrument performance between calibrations,see ISO/ASTM 51261 or instrument-specific operating manu-als, or both.6. Dose Mapping6.1 Dose Mapping for Operational Qualification of theIrradiation Facility:6.1.1 As specified in P
48、ractices ISO/ASTM 51204, ISO/ASTM 51431, ISO/ASTM 51608, ISO/ASTM 51649, ISO/ASTM 51702, ISO/ASTM 51818 and ISO 11137-1, performirradiation facility dose mapping to characterize the irradiatorwith respect to the dose distribution and reproducibility ofabsorbed dose delivery. This should be performed
49、 in accor-dance with a formal validation program over the operationalrange that will be used in the irradiation of products.6.1.2 Perform irradiation facility dose mapping by placingdosimeters in a number of process loads of reference materialthat fills the container to its design volume limits. The numberof process loads to be dose mapped should be large enough (3or more) to determine the variability of dose. For thoseirradiation facilities that vary operating parameters whichimpact dose distribution, dose mapping should be carried outover a range of s
