ASTM 52303-24

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.
Designation: ISO/ASTM 52303 − 2015(E) 52303 − 24
Standard Guide for
Absorbed-Dose Mapping in Radiation Processing Facilities
This standard is issued under the fixed designation ISO/ASTM 52303; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
Historically, this document’s scope includes all dose mapping activities (OQ and PQ) for the three
common forms of radiation utilized in facilities. Ongoing work within E61.03 aims to provide the user
with additional guidance on considerations specific to each radiation source type and absorbed-dose
mapping activities. The intent is to keep this document largely whole while these standards are
published over the upcoming years, updating specific sections to reference further guidance that can
be obtained in external documents. A major revision to this document is planned after the balance of
additional guidance documents are approved at which time this Introduction will be removed.
1. Scope
1.1 This document provides guidance in determining absorbed-dose distributions (mapping) in products, materials or substances
irradiated in gamma, X-ray (bremsstrahlung) and electron beam facilities.
NOTE 1—For irradiation of food and the radiation sterilization of health care products, specific ISO and ISO/ASTM standards containing dose mapping
requirements exist. See ISO/ASTM Practices 51431, 51608, 51649, 51702 and 51818 and ISO 11137-1. Regarding the radiation sterilization of health
care products, in those areas covered by ISO 11137-1, that standard takes precedence.
1.2 This guide is one of a set of standards that provides recommendations for properly implementing dosimetry in radiation
processing. itIt is intended to be read in conjunction with ISO/ASTM 52628.
1.3 Methods of analyzing the dose map data are described. Examples are provided of statistical methods that may be used to
analyze dose map data.
1.4 Dose mapping for bulk flow processing and fluid streams is not discussed.
1.5 Dosimetry is an element of a total quality management system for an irradiation facility. Other controls besides dosimetry may
be required for specific applications such as medical device sterilization and food preservation.
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 and healthsafety, health, and environmental practices and determine
the applicability of regulatory requirementslimitations prior to use.
This guide 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 . Originally developed as a joint ASTM/ISO standard in conjunction with ISO/TC 85/WG 3.
Current edition approved Feb. 9, 2015Jan. 1, 2024. Published January 2024June 2015. Originally published as ASTM. Originally approved in 2003. E2303–03. Last
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previous ASTM edition E2303–11approved . The present International Standard ISO/ASTM 52303–2015(E) replaces ASTM in 2015 as ISO/ASTM 52303–2015(E).
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DOI:10.1520/52303-24.E2303–11 .
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
52303 − 24
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
E178 Practice for Dealing With Outlying Observations
E2232 Guide for Selection and Use of Mathematical Methods for Calculating Absorbed Dose in Radiation Processing
Applications
E3083 Terminology Relating to Radiation Processing: Dosimetry and Applications
E3239 Guide for Using Statistical Process Control Principles for Routine Dosimetry in Radiation Processing
E3270 Guide for Operational Qualification of Gamma Irradiators
2.2 ISO/ASTM Standards:
51261 Guide for Selection and Practice for Calibration of Routine Dosimetry Systems for Radiation Processing
51431 Practice for Dosimetry in Electron Beam and X-Ray (Bremsstrahlung) Irradiation Facilities for Food Processing
51608 Practice for Dosimetry in an X-ray (Bremsstrahlung) Facility for Radiation Processing
51649 Practice for Dosimetry in an Electron Beam Facility for Radiation Processing at Energies between 300 keV and 25 MeV
51702 Practice for Dosimetry in a Gamma Irradiation Facility for Radiation Processing
51707 Guide for Estimating Uncertainties in Dosimetry for Radiation Processing
51818 Practice for Dosimetry in an Electron Beam Facility for Radiation Processing at Energies between 80 and 300 keV
52628 Practice for Dosimetry in Radiation Processing
2.3 International Commission on Radiation Units and Measurements Reports:
ICRU Report 85a Fundamental Quantities and Units for Ionizing Radiation
2.4 International Organization for Standardization:
ISO 11137-1 Sterilization of health care products – Radiation – Part 1: Requirements for development, validation, and routine
control of a sterilization process for medical devices
ISO 14470 Food irradiation – Requirements for the development, validation and routine control of the process of irradiation
using ionizing radiation for the treatment of food
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 – Basis and general concepts and associated terms
3. Terminology
3.1 Definitions:
3.1.1 absorbed-dose mapping—measurement of absorbed dose within an irradiated product to produce a one-, two- or
three-dimensional distribution map of absorbed dose.
3.1.1.1 Discussion—
For a process load, such a dose map is obtained using dosimeters placed at specified locations within the process load.
3.1.2 calibration curve (VIM:2008)—expression of the relation between indication and corresponding measured quantity value.
3.1.2.1 Discussion—
In radiation processing standards, the term “dosimeter response” is generally used for “indication.”
3.1.3 dose map, dose mapping—see absorbed-dose mapping.
3.1.4 dose uniformity ratio—ratio of the maximum to the minimum absorbed dose within the irradiated product.
For referenced ASTM and ISO/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 Commission on Radiation Units and Measurements, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814.
Available from International Organization for Standardization (ISO), 1 rue de Varembé, Case postale 56, CH-1211, Geneva 20, Switzerland.
Document produced by Working Group 1 of the Joint Committee for Guides in Metrology (JCGM/WG 1). 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/WG 2). Available free of charge at the BIPM website
(http://www.bipm.org).
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3.1.4.1 Discussion—
The concept is also referred to as the max/min dose ratio. Product generally refers to the “process load.”
3.1.5 dose zone—a region or discrete point(s) within a process load that receives the same absorbed dose within the statistical
uncertainty of the irradiation process and absorbed-dose measurement(s).
3.1.6 installation qualification (IQ)—process of obtaining and documenting evidence that equipment has been provided and
installed in accordance with its specification.
3.1.7 irradiation container—holder in which process load is transported through the irradiator.
3.1.7.1 Discussion—
“Irradiation container” is often referred to simply as “container” and can be a carrier, cart, try, product carton, pallet, product
package or other holder.
3.1.8 operational qualification (OQ)—process of obtaining and documenting evidence that installed equipment operates within
predetermined limits when used in accordance with its operational procedures.
3.1.9 performance qualification (PQ)—process of obtaining and documenting evidence that the equipment, as installed and
operated in accordance with operational procedures, consistently performs in accordance with predetermined criteria and thereby
yields product meeting its specification.
3.1.10 process load—a volume of material with a specified product loading configuration irradiated as a single entity.
3.1.11 processing category—group of different product that can be processed together.
3.1.11.1 Discussion—
Processing categories can be based on, for instance, composition, density or dose requirements.
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, throughput rate, 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.
3.1.13.1 Discussion—
This position may be a location of minimum or maximum dose in the process load or it may be an alternate convenient location
in, on or near the process load where the relationship of the dose at this position with the minimum and maximum dose has been
established.
3.1.14 simulated product—material with absorption and scattering properties similar to those of the product, material or substance
to be irradiated.
3.1.14.1 Discussion—
Simulated product is used during irradiator characterization as a substitute for the actual product, material or substance to be
irradiated. When used in routine production runs in order to compensate for the absence of product, simulated product is sometimes
referred to as compensating dummy. When used for absorbed-dose mapping, simulated product is sometimes referred to as
phantom material.
3.2 Definitions of other terms used in this standard that pertain to radiation measurement and dosimetry may be found in
Terminology E170E3083. Definitions in E170E3083 are compatible with ICRU Report 60;85a; that document, therefore, may be
used as an alternative reference.
4. Significance and use
4.1 This guide is one of a set of guides and practices that provide recommendations for properly implementing dosimetry in
radiation processing. In order to understand and effectively use this and other dosimetry standards, consider first “Practice for
Dosimetry in Radiation Processing,” ASTM/ISO 52628, which describes the basic requirements that apply when making absorbed
dose measurements in accordance with the ASTM E10.01E61 series of dosimetry standards. In addition, ASTM/ISO 52628
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provides guidance on the selection of dosimetry systems and directs the user to other standards that provide information on
individual dosimetry systems, calibration methods, uncertainty estimation and radiation processing applications.
4.2 Radiation processing is carried out under fixed path conditions where (a) a process load is automatically moved through the
radiation field by mechanical means or (b) a process load is irradiated statically by manually placing product at predetermined
positions before the process is started. In both cases the process is controlled in such a manner that the process load position(s)
and orientation(s) are reproducible within specified limits.
NOTE 2—Static irradiation encompasses irradiation of the process load using either manual rotation, no rotation or automated rotation.
4.3 Some radiation processing facilities that utilize a fixed conveyor path for routine processing may also characterize a region
within the radiation field for static radiation processing, sometimes referred to as “Off Carrier” processing.
4.4 Many radiation processing applications require a minimum absorbed dose (to achieve a desired effect or to fulfill a legal
requirement), and a maximum absorbed dose (to ensure that the product, material or substance still meets functional specifications
or to fulfill a legal requirement).
4.5 Information from the dose mapping is used to:
4.5.1 Characterize the radiation process and assess the reproducibility of absorbed-dose values, which may be used as part of
operational qualification and performance qualification.
4.5.2 Determine the spatial distribution of absorbed doses and the zone(s) of maximum and minimum absorbed doses throughout
a process load, which may consist of an actual or simulated product.
4.5.3 Establish the relationship between the dose at a routine monitoring position and the dose within the minimum and maximum
dose zones established for a process load.
4.5.4 Verify mathematical dose calculation methods. See ASTM Guide E2232.
4.5.5 Determine the effect of process interruptions on the distribution of absorbed dose and the magnitude of the minimum and
maximum doses.
4.5.6 Assess the impact on the distribution of absorbed dose and the magnitude of the minimum and maximum doses resulting
from the transition from one process load to another where changes, for example, in product density or product loading pattern
may occur.
5. Prerequisites
5.1 Prerequisites to Dose Mapping: Installation Qualification and Dosimetry System Calibration:
5.1.1 Prior to performing dose mapping for irradiator operational qualification (OQ) and performance qualification (PQ), 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 of the beam
(electron energy, average beam current, and if applicable, scan width and scan uniformity). Refer to ISO/ASTM 51431, 51608,
51818, 51649 and ISO 11137-1.
5.1.1.2 For gamma irradiation facilities, dosimetric testing is not required during IQ; however, the activity of the source and
location of the individual components of the source should be confirmed and documented. confirmed. Refer to ISO/ASTM 51702
and ISO 11137-1.
5.1.2 Select an appropriate dosimetry system(s) for the dose mapping exercises. See 6.2.4.1 and ISO/ASTM 52628 for guidance.
5.2 Calibration of the Dosimetry System:
5.2.1 Prior to use, the dosimetry system, consisting of dosimeters measurement instruments and their associated reference
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standards, and procedures for the system’s use, should be calibrated in accordance with the user’s documented procedure that
specifies details of the calibration process and quality assurance requirements. Calibration methods are described in ISO/ASTM
51261.
NOTE 3—A dosimetry system calibration obtained using irradiation conditions different from the conditions of use may be used for relative dose
measurement applications. For example, an irradiation facility may perform a lab-based calibration with subsequent verification using reference standard
dosimeters under the conditions of use. While dose mapping at the irradiation facility may be performed using dose values from the lab-based calibration
(prior to completing the verification exercise) to assess the dose distribution and locations of minimum and maximum absorbed dose, these dose
measurements would be considered preliminary (i.e. relative) pending the outcome of the verification exercise.
5.2.2 For the calibration of the instruments, and for the verification of instrument performance between calibrations, see
ISO/ASTM 51261 or instrument-specific operating manuals, or both.
6. Dose mapping
6.1 Dose Mapping for Operational Qualification of the Irradiation Facility:
6.1.1 As specified in ISO/ASTM Practices 51431, 51608, 51649, 51702, and ISO 11137-1, perform irradiation facility dose
mapping to characterize the irradiator with respect to the dose distribution and reproducibility of absorbed dose delivery. This
should be performed in accordance with a formal validation program, and should cover the operational range that will be used in
the irradiation of products.
6.1.2 Perform irradiation facility dose mapping by placing dosimeters in a number of process loads of reference material that fills
the container to its design volume limits. limits or the volume limits based on actual processing conditions. The number of process
loads to be dose mapped should be large enough (3 or more) to determine the variability of dose. For those irradiation facilities
that vary operating parameters which impact dose distribution, dose mapping should be carried out over a range of selected
operating parameters which cover the operational limits to be used in the irradiation of products.
6.1.2.1 Specific to Photon-based Facilities (gamma or X-ray)—Material densities should be within the density range for which the
irradiator is to be used. When processing multiple densities, dose mapping should be doneperformed for at least two densities
densities: one close to the minimum and maximum density to be processed density and one close to the maximum density to assess
the impact density has on the magnitude and distribution of the absorbed dose. A user may consider dose mapping for additional
intermediate densities to gain additional performance information.
NOTE 4—See ASTM Guide E3270 for more comprehensive guidance on performing OQ dose mapping specific to gamma irradiation facilities.
6.1.2.2 Specific to Electron Beam Facilities—For irradiation facility dose mapping, use one or more reference materials having
densities within the density range for which the irradiator is to be used.
6.1.2.3 Determine absorbed-dose distribution throughout the process load for each product path through the irradiation field and
each set of process parameters.
NOTE 5—Additional ways to influence the absorbed-dose distribution within a given process load include: performing single- versus double-sided
irradiation in electron beam and X-ray facilities, or using multiple source rack(s) or source rack positioning changes in gamma irradiators.
6.1.2.4 For each process load, place a sufficient number of dosimeters in an array to determine the absorbed-dose distribution.
Dosimeter strips or sheets may be used to increase the spatial resolution of the dose map. An example of dosimeter placement array
is given in Fig. 1.
6.1.2.5 Measure the dose at the same positions in three or more replicate process loads to determine the variability of the measured
absorbed dose and absorbed-dose distribution for each product path and set of process parameters.
(1) For process loads transported through the irradiation field, a sufficient number of similar process loads should precede and
follow those being dose mapped to minimize variations on the absorbed-dose distribution in the dose-mapped process loads.
(2) Depending on the irradiator design, additional dose map studies may be needed to determine effects on dose and dose
distribution associated with changes during processing in process loading configurations and their density (sometimes referred to
as “phase-in and phase-out” effects). The effect of density changes on dose and dose distribution can be evaluated by irradiating
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NOTE 1—In this drawing the small squares represent dosimeter positions. The “Front” is defined as the initial and in some cases only surface to directly
face the radiation source during processing. The number of dosimeters and the number of planes (surfaces) to be mapped will depend on several factors,
including but not limited to, the radiation type (electrons versus photons), single- versus double-sided irradiation, and resolution of absorbed dose
required.
FIG. 1 An Example of a Dosimeter Placement Array in a Three-Dimensional Grid Pattern for an Operational Qualification Dose Mapping
two different density process loads sequentially and dose mapping the last process load of the one density and the first process load
of the second density and comparing these results against the results obtained from the uniform density dose map described in
6.1.2.5, (1).
(3) If OQ measurements show that effects of “phase-in/phase-out” may exist, then the effect on actual product may also have
to be assessed during PQ (see 6.2.5.1).
6.1.2.6 Following irradiation, retrieve and measure the response of each dosimeter, and evaluate the data in accordance with
established procedures (see Section 7).
6.1.3 If changes are made to the irradiation system that could affect the absorbed-dose or absorbed-dose distribution, it may be
necessary to repeat the dose mapping.
NOTE 6—ISO 11137-1 provides additional guidance regarding changes to the irradiation system and recommended post-change qualification activities.
6.1.4 The use of mathematical models in determining dosimeter locations for dose mapping or in predicting dose map results may
be useful. See Guide E2232 for guidance.
6.2 Dose Mapping for Performance Qualification of Process Loads
6.2.1 Perform dose mapping for specific products and load configurations to determine the dose distribution expected during the
routine processing of process loads. Products, materials or substances should be actual product or may be simulated product of
materials with similar density, distributions and packaging configuration as the actual products.
6.2.2 If a routine monitoring position is used for process monitoring, the relationships between minimum dose, maximum dose
and the dose at the routine monitoring position should be established.
6.2.3 Specify a loading pattern that describes the products, materials or substances contained within the process load, including
dimensions, mass or density, and if applicable, the orientation of the product within the process load as well as the orientation of
the process load itself with respect to the radiation field.
6.2.4 Specify or determine the location of the dosimeters used for the dose map, taking into consideration voids, density variations
or any material interfaces that may cause significant localized dose gradients that could affect the location of minimum or
maximum dose, or both, within the process load.
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6.2.4.1 Use dosimeters capable of measuring any localized dose gradients and of a size that does not significantly influence the
radiation field or the interpretation of absorbed-dose measurements.
6.2.4.2 Process loads containing voids, density variations, or materials interfaces that could cause localized dose gradients require
that the dosimeters to be placed directly on the material surfaces. Selection of the dosimeter positions for dose mapping should
include areas of suspected high dose gradients based on a physical assessment of the materials and their composition that make
up the process load being dose mapped. These positions may be concentrated in the expected zones of minimum or maximum dose,
or both, known from the irradiator operational qualification (OQ) dose map. Heterogeneous products such as metal implants or
certain foods may require placement of appropriately sized dosimeters positioned at internal locations within the individual
products. This may involve cutting open the individual product inside the package to permit dosimeter positioning and retrieval,
or removal of dosimeters from their protective packaging to facilitate dosimeter placement. The latter requires assurances that the
dosimeters can be characterized and perform acceptably when used without protective packaging.
NOTE 7—When dosimeters are calibrated in their protective packaging but used outside the packaging for a specific application, this usage may alter the
calibrated state of the dosimeters. The impact on absorbed-dose measurement for this usage should be assessed.
6.2.4.3 The use of mathematical models in determining dosimeter locations for dose mapping or in predicting dose map results
may be useful. See Guide E2232 for guidance.
6.2.5 Measure the dose at the same position(s) in the maximum and minimum dose zones in three or more process loads to
determine the variability of the absorbed-dose delivery and measurements. Each process load should contain similar materials and
dosimeter placements that are configured in the same way and should be processed under the same operating conditions.
6.2.5.1 A sufficient number of process loads should precede and follow the dose mapped process loads to minimize phase-in/out
effects (see 6.1.2.5, Item 1).
6.2.6 Doses outside of the product dose specification are acceptable for dose mapping purposes. See Note 910 in 7.2.4 for
additional discussion.
6.2.7 Repeat the dose mapping procedure if a change is made to the product or the irradiation facility that may impact the
previously characterized dose distribution.
6.2.8 If measurements done according to 6.1.3 lead to the conclusion that dose or dose distribution has changed, then repeat of
product dose map is needed.
6.2.9 Practical considerations for Product Dose Mapping (see Mapping.6.2.1).
6.2.9.1 Facilities typically irradiate a variety of products and dose mapping of all products may be impractical. If products have
similar loading configurations and are known to have densities and radiation absorption characteristiccharacteristics equivalent to
a product (actual or simulated) that has already been dose mapped, then it is not necessary to perform dose mapping for them, and
a processing category can be established consisting of product that can be irradiated together.
6.2.9.2 Criteria for including product in processing categories shall be documented, and should include:
(1) dimension of the process load
(2) weight of the process load
(3) density of the process load
(4) composition of the product
(5) orientation of the product items with the process load
(6) number of product items within the process load
(7) the required minimum dose
(8) the maximum acceptable dose
6.2.9.3 If facilities irradiate only process loads that can be demonstrated to have the same dose distribution characteristics as those
used in the operational qualification (OQ) dose mapping(s) discussed in 6.1, then it is not necessary to conduct performance
qualification (PQ) dose mapping.
6.3 Other Dose Mapping Studies—The dynamics of routine processing may require additional studies relevant to each processing
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path be performed during operational or performance qualification, or both, to further characterize irradiator performance and its
impact on the magnitude and distribution of absorbed dose. The number of studies required will generally depend on the specific
irradiation system; however, selected studies common to many irradi
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