ASTM ISO/ASTM51818-20

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
ISO/ASTM 51818:2013(E)
ISO/ASTM 51818 − 2020(E)
Standard Practice for
Dosimetry in an Electron Beam Facility for Radiation
Processing at Energies Between 80 and 300 keV
This standard is issued under the fixed designation ISO/ASTM 51818; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision.
INTRODUCTION
Low energy electron beams, typically 80 – 300 keV, are used in several industrial processes, from
curing of prints and crosslinking of plastic foils to surface sterilization of containers for pharmaceu-
ticals and medical devices. These different applications are addressed through IQ, OQ, PQ and routine
dose monitoring, although radiation curing and crosslinking might only require that reproducibility of
dose delivery during execution of the process can be demonstrated.
This standard practice describes the dose measurements that might be required for full documen-
tation of a low energy electron beam sterilization process. The dose measurement requirements for
sterilization using low energy electron beams are derived from the international standard for radiation
sterilization ISO 11137-1.
Not all low energy e-beam applications require dose measurement documentation with traceability
to national standards. For radiation curing or crosslinking processes, for example, it might not be a
requirement that calibration of the dosimetry system is established and maintained with traceability to
national or international standards. The user must decide whether or not measurement traceability is
required for the specific irradiation process, and it is the user who therefore accepts responsibility for
reproducibility and documentation of the process.
1. Scope
1.1 This practice covers dosimetric procedures to be followed in installation qualification, operational qualification and
performance qualification (IQ, OQ, PQ), and routine processing at electron beam facilities to ensure that the product has been
treated with an acceptable range of absorbed doses. Other procedures related to IQ, OQ, PQ, and routine product processing that
may influence absorbed dose in the product are also discussed.
1.2 The electron beam energy range covered in this practice is between 80 and 300 keV, generally referred to as low energy.
1.3 Dosimetry is only one component of a total quality assurance program for an irradiation facility. Other measures may be
required for specific applications such as medical device sterilization and food preservation.
1.4 Other specific ISO and ASTM standards exist for the irradiation of food and the radiation sterilization of health care
products. For the radiation sterilization of health care products, see ISO 11137.11137-1. In those areas covered by ISO
11137,11137-1, that standard takes precedence. For food irradiation, see ISO 14470:2011.14470. Information about effective or
regulatory dose limits for food products is not within the scope of this practice (see ASTM F1355 and F1356).
1.5 This document is one of a set of standards that provides recommendations for properly implementing and utilizing dosimetry
in radiation processing. processing, and describes a means of achieving compliance with the requirements of ISO/ASTM 52628.
It is intended to be read in conjunction with ASTMISO/ASTM E223252628, “Practice for Dosimetry in Radiation Processing”.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
This practice is under the jurisdiction of ASTM Committee E61 on Radiation Processing and is the direct responsibility of Subcommittee E61.03 on Dosimetry
Application, and is also under the jurisdiction of ISO/TC 85/WG 3.
ε1
Current edition approved April 9, 2013. March 2020. Published June 2013June 2020. Originally published as ASTM E1818–96. Last previous ASTM edition E1818–96 .
ε1
ASTM E1818–96 was adopted in 1998 with the intermediate designation ISO 15573:1998(E). The present ThirdThe present Fourth Edition of International Standard
ISO/ASTM 51818:2013(E)51818:2020(E) is a major revision of the SecondThird Edition of ISO/ASTM 51818:2009(E). 51818:2013(E).
© ISO/ASTM International 2020 – All rights reserved
ISO/ASTM 51818:2020(E)
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced documents
2.1 ASTM Standards:
E170 Terminology Relating to Radiation Measurements and Dosimetry
E2232 Guide for Selection and Use of Mathematical Methods for Calculating Absorbed Dose in Radiation Processing
Applications
E2303E3083 Guide for Absorbed-Dose Mapping in Radiation Processing FacilitiesTerminology Relating to Radiation
Processing: Dosimetry and Applications
E2628 Practice for Dosimetry in Radiation Processing
E2701 Guide for Performance Characterization of Dosimeters and Dosimetry Systems for Use in Radiation Processing
F1355 Guide for Irradiation of Fresh Agricultural Produce as a Phytosanitary Treatment
F1356 Guide for Irradiation of Fresh, Frozen or Processed Meat and Poultry to Control Pathogens and Other Microorganisms
2.2 ISO Standards:
11137-1:2006 Sterilization of health care products–Radiation–Part 1: Requirements for development, validation and routine
control of a sterilization process for medical devices
14470:2011 Food irradiation–Requirements for the development, validation and routine control of the ionizing radiation used for
the treatment of food
17025:2005 General requirements for the competence of testing and calibration laboratories
2.2 ISO/ASTM Standards:
51261 Practice for Calibration of Routine Dosimetry Systems for Radiation Processing
51275 Practice for Use of a Radiochromic Film Dosimetry System
51607 Practice for Use of an Alanine-EPR Dosimetry System
51649 Practice for Dosimetry in an Electron Beam Facility for Radiation Processing at Energies between 300 keV and 25 MeV
51650 Practice for Use of a Cellulose Triacetate Dosimetry System
51707 Guide for Estimating Uncertainties in Dosimetry for Radiation Processing
52303 Guide for Absorbed-Dose Mapping in Radiation Processing Facilities
52628 Practice for Dosimetry in Radiation Processing
52701 Guide for Performance Characterization of Dosimeters and Dosimetry Systems for Use in Radiation Processing
2.3 International Commission on Radiation Units and Measurements (ICRU) Report:
ICRU Report 85a Fundamental Quantities and Units for Ionizing Radiation
ICRU Report 80 Dosimetry Systems for Use in Radiation Processing
ICRU Report 85a Fundamental Quantities and Units for Ionizing Radiation
2.4 ISO Standards:
11137-1:2006 Sterilization of health care products – Radiation – Part 1: Requirements for development, validation and routine
control of a sterilization process for medical devices
14470:2011 Food irradiation – Requirements for the development, validation and routine control of the ionizing radiation used
for the treatment of food
17025:2017 General requirements for the competence of testing and calibration laboratories
12749-4 Nuclear energy, nuclear technologies, and radiological protection – Vocabulary – Part 4: Dosimetry for radiation
processing
2.5 Joint Committee for Guides in Metrology (JCGM) Reports:
JCGM 100:2008, GUM 1995, with minor corrections, Evaluation of measurement data – Guide to the expression of uncertainty
in measurement
JCGM 200:2012, VIM International vocabulary of metrology – Basic and general concepts and associated terms
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
Available from International Organization for Standardization (ISO), 1, ch. de la Voie-Creuse, CP 56, CH-1211 Geneva 20, Switzerland, http://www.iso.org.
Available from the International Commission on Radiation Units and Measurements, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814, U.S.A.
Document produced by Working Group 1 of the Joint Committee for Guides in Metrology (JCGM WG1), Available free of charge at the BIPM website
(http://www.bipm.org).
Document produced by Working Group 2 of the Joint Committee for Guides in Metrology (JCGM WG2), Available free of charge at the BIPM website
(http://www.bipm.org).
© ISO/ASTM International 2020 – All rights reserved
ISO/ASTM 51818:2020(E)
3. Terminology
3.1 Definitions:
3.1.1 absorbed dose (D)—quantity of ionizing radiation energy imparted per unit mass of a specified material. The SI unit of
absorbed dose is the gray (Gy), where 1 gray is equivalent to the absorption of 1 joule per kilogram of the specified material (1
Gy = 1 J/kg). The mathematical relationship is the quotient of dε by dm, where dε is the mean incremental energy imparted by
¯ ¯
ionizing radiation to matter of incremental mass dm.m (ICRU-85a), thus
D 5 dε¯⁄ dm
3.1.1.1 Discussion—
The SI unit of absorbed dose is the gray (Gy), where 1 gray is equivalent to the absorption of 1 joule per kilogram of the specified
material (1 Gy = 1 J / kg).
3.1.1.2 Discussion—
Throughout this practice, “absorbed dose” is referred to as “dose”.
3.1.2 approved laboratory—laboratory that is a recognized national metrology institute; or has been formally accredited to
ISO/IEC 17025; or has a quality system consistent with the requirements of ISO/IEC 17025.
3.1.3 average beam current—time-averaged electron beam current.
3.1.4 beam width—dimension of the irradiation zone perpendicular to the direction of product movement, at a specified distance
from the accelerator window.
3.1.5 calibration curve—expression of the relation between indication and corresponding measured quantity value (VIM).
3.1.5.1 Discussion—
In radiation processing standards, the term ‘dosimeter response’ is generally used for ‘indication.’
3.1.6 depth-dose distribution—variation of absorbed dose with depth from the incident surface of a material exposed to a given
radiation.
3.1.7 dosimeter—device that, when irradiated, exhibits a quantifiable change that can be related to absorbed dose in a given
material using appropriate measurement instruments and procedures.
3.1.8 dosimetry system—system interrelated elements used for determiningmeasuring absorbed dose, consisting of dosimeters,
measurement instruments and their associated reference standards, and procedures for the system’s use.
3.1.9 electron beam energy—kinetic energy of the accelerated electrons in the beam.
3.1.10 measurement uncertainty—non-negative parameter characterizing the dispersion of the quantity values being attributed
to a measurand, based on the information used (VIM).
3.1.11 metrological traceability—property of the result of a measurement or the value of a standard whereby it result whereby
the result can be related to stated references, usually national or international standards, through an a reference through a
documented unbroken chain of comparisons all having stated uncertainties.calibrations, each contributing to the measurement
uncertainty (VIM).
3.1.12 reference material—homogeneous material of known radiation absorption and scattering properties used to establish
characteristics of the irradiation process, such as scan uniformity, depth-dose distribution, and reproducibility of dose delivery.
3.1.13 routine monitoring position—position where absorbed dose is monitored during routine processing to ensure that the
product is receiving the absorbed dose specified for the process.
3.1.14 uncertainty—uncertainty budget—parameter associated with the result statement of a measurement that characterizes the
dispersion uncertainty, of the values that could reasonably be attributed to the measurand or derived quantity (see ISO/ASTM
Guide components of that measurement uncertainty, and of their calculation and combination (VIM).51707).
3.1.14.1 Discussion—
An uncertainty budget should include the measurement model, estimates, and measurement uncertainties associated with the
quantities in the measurement model, covariances, type of applied probability density functions, degrees of freedom, type of
evaluation of measurement uncertainty, and any coverage factor.
3.2 Definitions of Terms Specific to This Standard:
© ISO/ASTM International 2020 – All rights reserved
ISO/ASTM 51818:2020(E)
3.2.1 D —absorbed dose to water in the first micrometer of water equivalent absorbing material (1).
μ
3.2.1.1 Discussion—
D is a term used by an approved laboratory to specify reported surface dose values of transfer standard dosimeters based on
μ
adjustments made to account for user site specific calibration irradiation conditions.
3.2.2 linear process rate—product length irradiated per unit time to deliver a given dose.
3.2.3 mass process rate—product mass irradiated per unit time to deliver a given dose.
3.2.4 area process rate—product area irradiated per unit time to deliver a given dose.
NOTE 1—Definitions of other terms used in this standard that pertain to radiation measurement and dosimetry may be found in ISO/ASTM 52628,
ASTM Terminology E3083, and ISO 12749-4. Definitions in these documents are compatible with ICRU Report 85a, and therefore, may be used as
alternative references. Where appropriate, definitions used in this standard have been derived from, and are consistent with, general metrological
definitions given in the VIM.
3.3 Definitions of other terms used in this standard that pertain to radiation measurement and dosimetry may be found in
Terminology E170. Definitions in Terminology E170 are compatible with ICRU Report 85a; that document, therefore, may be used
as an alternative reference.
4. Significance and use
4.1 A variety of irradiation processes usesuse low energy electron beam facilities to modify product characteristics. Dosimetry
requirements, the number and frequency of measurements, and record keeping requirements will vary depending on the type and
end use of the products being processed. Dosimetry is often used in conjunction with physical, chemical, or biological testing of
the product, to help verify specific treatment parameters.
NOTE 2—In many cases dosimetry results can be related to other quantitative product properties; for example, gel fraction, melt flow, elastic modulus,
molecular weight distribution, or cure analysis tests.degree of cure.
4.2 Radiation processing specifications usually include a minimum or maximum absorbed dose limit, or both. For a given
application these limits may be set by government regulation or by limits inherent to the product itself.
4.3 Critical processoperating parameters must be controlled to obtain reproducible dose distribution in processed materials. The
electron beam energy, beam current, beam width and process line speed (conveying speed) affect absorbed dose.
4.4 Before any electron beam facility can be routinely utilized, it must be validated to determine its effectiveness. characterized
to determine the relationship between dose to product and the main operating parameters. This involves testing of the process
equipment, calibrating the measuring instruments and the dosimetry system, and demonstrating the ability to consistently deliver
the required dose within predetermined specifications.
4.5 In order to establish metrological traceability for a dosimetry system to be effective in low-energy electron irradiation
applications and to measure doses with an acceptablea known level of uncertainty, it is necessary to calibrate the dosimetry system
under irradiation conditions that are consistent with those encountered in routine use. For example, a dosimetry system calibration
conducted using penetrating gamma radiation or high energy electrons may result in significantly inaccurate significant dose
measurement errors when the dosimetry system is used at low energy electron beam facilities. Details of calibration are discussed
in Section 5.
5. Selection and calibration of the dosimetry system
5.1 Selection of Dosimetry Systems:
5.1.1 ASTMISO/ASTM E262852628 identifies requirements for selection of dosimetry systems. For use withdosimetry at
low-energy electron beam facilities consideration should specifically be given to the limited range of such electrons which might
give rise to significant dose gradients through the thickness of the dosimeter. By choosing thin film dosimeters this problem can
be limited (see minimized Note 2) (1).
5.1.2 When selecting a dosimetry system, consideration should be given to effects of influence quantities on the response of the
dosimeter (see ISO/ASTM E270152701). One such influence quantity is might be irradiation atmosphere, and some low-energy
accelerator applications involve irradiation in oxygen-free conditions.conditions which might influence dosimeter response.
5.2 Calibration of the Dosimetry System:
5.2.1 The dosimetry system shall be calibrated prior to use and at intervals thereafter in accordance with the user’s documented
procedure that specifies details of the calibration process and quality assurance requirements. Calibration General conditions for
calibration methods are given in ISO/ASTM 51261.
NOTE 3—For some applications it might not be a requirement that calibration of the dosimetry system is established and maintained with traceability
The boldface numbers in parentheses refer to the bibliography at the end of this standard.
© ISO/ASTM International 2020 – All rights reserved
ISO/ASTM 51818:2020(E)
to national or international standards. The user must decide whether or not measurement traceability is required for the specific irradiation process, and
it is the user who therefore accepts responsibility for reproducibility and documentation of the process. For more information on relative dose
measurements see Annex A4.
5.2.2 The calibration irradiation may be performed by irradiating the dosimeters at (a) an approved laboratory or (b) a
production irradiator under actual production irradiation conditions an irradiator where the normal irradiation conditions are used
for calibration irradiation of routine dosimeters together with transfer standard dosimeters issued and analyzed by an approved
laboratory. In case of option (a), the resulting calibration curve shall be verified for the actual conditions of use (see ISO/ASTM
51261). The same applies for option (b) if irradiation conditions different from the actual production conditions have been used
for the calibration irradiation.
NOTE 4—While 5.2.2 is valid for most dosimeter calibration irradiations, it must be recognized that the irradiation of various dosimeters with low
energy electrons (less than 300 keV) may will likely lead to dose gradients through the thickness of the dosimeter. When the dosimeter response is
measured, this will lead to an apparent dosea dose value (an apparent dose, D ) that is related to the dose distribution. For based on the assumption
app
that there are no dose gradients within the dosimeter. However, if dose gradients exist within the dosimeter, then for a given set of irradiation conditions,
the apparent dose will depend on the thickness of the dosimeter, i.e., dosimeters with different thickness will measure different apparent doses. One
solution to overcome this problem is that all dose measurements are specified as dose to water in the first micrometer of the water equivalent absorbing
material. This is given the symbol D and is independent of the dosimeter thickness (1).Annex A2 The dose estimate for the calibration is carried out
μ
by the approved laboratory that issues the transfer standard dosimeters (describes the application of this principle for dose measurements carried out
during calibraton.5.2.2), and this dose can be given in terms of D (see Annex A2).
μ
NOTE 5—Some applications may not require dose measurements to be traceable to a national standard Dose gradient within a dosimeter is most
pronounced in dosimeters with thicknesses that represent a significant fraction of the electron range (see Annex A4Fig. A2.1). Using thin dosimeters, e.g.
in the order of 10 μm, will reduce the gradient and hence the difference between dose at the front and the back of the dosimeter.
5.3 Measurement Instrument Calibration and Performance Verification—For the calibration of the instruments, and for the
verification of instrument performance between calibrations, ISO/ASTM 51261, the correspondingrelevant ISO/ASTM or ASTM
standard for the dosimetry system, and/or instrument-specific operating manuals should be consulted.
6. Installation and operational qualification
6.1 Installation qualification (IQ) is carried out to demonstrate that the irradiation equipment and any ancillary items have been
supplied and installed in accordance with their specifications.
6.1.1 IQ typically involves measurement of depth-dose distribution and dose uniformity that can be used to calculate estimates
of process throughput to verify the equipment performance specifications.
NOTE 6—The dosimetric measurements to be carried out during IQ depend on the agreement between supplier and user of the facility. They might be
similar to the ones carried out during Operational Qualification (OQ).
NOTE 7—The dosimetric measurements carried out during IQ will often be the same as the ones carried out during Operational Qualification (OQ).
IQ typically involves the use of dosimetric measurements of beam penetration and dose uniformity that can be used to calculate estimates of process
throughput to verify the equipment performance specifications. A dosimetry system calibration curve obtained by dosimeter irradiation at another facility
might be used for these dose measurements, but in order to ensure that the dose measurements are traceable to national standards, valid, the calibration
curve must be verified for the actual conditions of use.
6.2 Operational qualification (OQ) is carried out to characterize the performance of the irradiation equipment with respect to
reproducibility of dose to product. For OQ product dose mapping guidance, see ASTM This is achieved through irradiator dose
mapping.E2303.
NOTE 8—Some applications may not require OQ dose measurements to be traceable to a national standard (see Annex A4).
NOTE 9—Dose measurements for OQ may have to be carried out using a dosimetry system calibration curve obtained by irradiation at another facility.
This calibration curve should be verified as soon as possible, verified, and corrections applied to the OQ dose measurements as needed.
NOTE 10—Distance between beam window and dosimeter should be specified for dose measurements carried out during OQ.
6.2.1 The performance of the low-energy electron beam facility depends primarily on the energy of the electrons. It mayelectron
beam energy. It might therefore be necessary to carry out separate OQ measurements for each energy selected for the operation
of the facility.
6.2.2 The relevant dosimetric OQ measurements are described in more detail in Annex A1. They typically include the following:
6.2.2.1 Dose as Function of Average Beam Current, Beam Width and Conveying Speed—Dose to the product irradiated in an
electron beam facility is proportional to average beam current (I), inversely proportional to conveying speed (V), and inversely
proportional to beam width (W ). The last relationship is valid for product that is conveyed through the beam zone perpendicular
b
to the beam width. This is expressed as:
Dose 5 ~K·I!/~V·W ! (1)
b
D 5 ~K·I!/~V·W ! (1)
b
where:
D = absorbed dose (Gy),
I = average beam current (A),
-1
V = conveying speed (m s ),
W = beam width (m), and
b
© ISO/ASTM International 2020 – All rights reserved
ISO/ASTM 51818:2020(E)
K = slope of the straight line relationship in Eq 1 (Gy · m ) / (A · s).
This straight-line relationship shall be determined for each energy selected for the operation of the facility. In order to determine
the relationship, dose shall be measured at a specific location using a number of selected parameter sets of beam current, conveying
speed and beam width to cover the operating range of the facility.
NOTE 11—Deviations from the straight-line relationship should be investigated.
6.2.2.2 Beam Width—The beam width is measured by placingirradiating dosimeter strips or discrete dosimeters at selected
intervals over the full beam width. Whenever possible, dosimeters should be placed beyond the expected beam width to identify
the limits of the full beam width.
6.2.2.3 Beam Penetration—Depth-dose Distribution—The beam penetrationdepth-dose distribution is measured using a stack of
thin dosimeters or by placing a dosimeter strip under thin layers of plastic foils.
(1) Calculation Methods—Beam penetration can be calculated using mathematical modeling (see ASTM E2232).
NOTE 12—Depth-dose distribution might be calculated using mathematical modeling (see ASTM E2232). Such calculations might be useful in
supporting and understanding measurements.
6.2.2.4 Dose Distribution on Reference Material—It may be needed to measure the The distribution of dose on or in a reference
material is measured by placing dosimeters on the surface of a reference material or within a reference material.
6.2.2.5 Process Interruption—A process interruption can be caused by, for example, failure of beam current delivery or by the
conveyor stopping. The effect of a process interruption on dose to product shall be determined, so that decisions about possible
product disposition can be made.
6.2.3 The measurements in 6.2.2 shall be repeated a sufficient number of times (three or more)(at least three) to allow
determination of the operating parameter variability based on a statistical evaluation of the dose measurements.
NOTE 13—The operating parameter variability can be determined from the scatter between repeated dose measurements made at different times using
identical operating parameter settings. Determination of this variability forms part of operational qualification. Operating parameter variability contributes
to uncertaintyvariability of measured doses. It is often difficult to separate effect of operating parameter variability and dosimeter reproducibility and thus
the measured variability determined will often be a combination of the two (2).
6.2.4 Based on the measured variability of the operating parameters, limits for their acceptable variation can be determined.
6.2.4 Requalification—OQ measurements shall be repeated at intervals specified by the user’s documented procedure. The
intervals shall be chosen to provide assurance that the irradiator is consistently operating within specifications. Requalification is
typically carried out on an annual cycle, with specific parts of requalification at shorter time intervals within this cycle. If
requalification measurements show that the OQ status of the irradiator has changed, then PQ might have to be repeated.
6.2.5 OQ measurements shall be repeated after assessment of changes of the irradiation facility that might affect dose or dose
distribution. The extent to which requalification is carried out shall be justified.
NOTE 14—Activities that might affect the OQ status of the irradiation facility include, but are not limited to:
replacement of accelerator emitter
replacement of accelerator window
replacement of window support grid
replacement of conveyor parts
change in electron energy
change in distance of accelerator window to product surface
– Replacement of accelerator emitter
– Replacement of accelerator window
– Replacement of window support grid
– Replacement of conveyor parts
– Change in electron energy
– Change in distance of accelerator window to product surface
7. Performance qualification
7.1 Performance Qualification (PQ) is the stage of validation which uses defined product to demonstrate that the facility
consistently operates in accordance with predetermined criteria to deliver specified doses, thereby resulting in product that meets
the specified requirements.
7.2 PQ dose mapping is carried out to demonstrate establish a set of operating parameters so that minimum dose to product
exceeds the dose required for the intended effect and that maximum dose to product does not exceed a maximum acceptable dose.
For PQ product dose mapping guidance, see ASTMISO/ASTM E230352303.
NOTE 15—Dose mapping exercises do not have to be carried out at the same dose as used for product irradiations. The use of higher doses, for
example,or lower doses can enable the dosimetry system to be used in a more accurate part of its operating range, thereby improving the overall accuracy
of the dose mapping.
NOTE 10—Some applications may not require PQ dose measurements to be traceable to a national standard (see Annex A4).
© ISO/ASTM International 2020 – All rights reserved
ISO/ASTM 51818:2020(E)
7.3 OQ dose mapping can in some cases be used as PQ dose mapping. For example, this is might be the case for irradiation
treatment of wide webs of infinite length. (roll-to-roll). In other cases, such as sterilization of complex product, it maymight be
required to carry out specific PQ product dose mapping.
7.4 During PQ dose mapping the locations and magnitudes of minimum and maximum doses, as well as the dose at a routine
monitoring position are position, should be determined.
7.5 The relationship between minimum and maximum doses and the dose at a routine monitoring position is determined.
7.6 PQ dose mapping measurements shall be repeated a sufficient number of times (three or more)(at least three) to allow
statistical evaluation and characterization of the dose distribution data.
7.7 Based on the measured uncertainties of this relationship (see 7.5) acceptable limits for variation of the dose process target
doses measured at the routine monitoring position to be measured during process irradiations canposition(s) and their acceptable
limits of variation might be determined (2).
7.8 Repeat of PQ dose mapping shall be considered if product is changed (thus affecting dose or dose distribution), or if the
OQ status of the irradiation facility is changed.
8. Routine process control
8.1 Monitoring of Operating Parameters—The operating parameters (beam energy, beam current, beam width and conveying
speed) shall be monitored and recorded continuously during the process or at intervals specified by the operator of the facility. The
intervals shall be chosen to provide assurance that the irradiator is consistently operating within specifications.
NOTE 16—Beam energy, beam current and beam width are usually not measured directly, but are obtained through indirect measurements. The
relationship between measured and actual values should be documented.
8.2 Measurement of Routine Dose—The dose at the routine monitoring position shallshould be measured at intervals specified
by the operator of the facility. The intervals shallsould be chosen to verify the irradiator operated within limits, and thereby
ensuring that the productprocess specifications were achieved. The rationale for the interval should be domented.
NOTE 12—Some applications may not require routine dose measurements to be traceable to a national standard (see Annex A4).
8.3 Pro
...