Standard Guide for Estimating Uncertainties in Dosimetry for Radiation Processing

SIGNIFICANCE AND USE
4.1 Gamma, electron, and X-ray (bremsstrahlung) facilities routinely irradiate a variety of products such as food, medical devices, aseptic packaging and commodities (see ISO/ASTM Practices 51204 and 51431). Process parameters must be carefully controlled to ensure that these products are processed within specifications (see ISO 11137, Section 2.3). Accurate dosimetry is essential in process control (see ISO/ASTM Guide 51261). For absorbed dose measurements to be meaningful, the combined uncertainty associated with these measurements must be estimated and its magnitude quantified.
NOTE 1 - For a comprehensive discussion of various dosimetry methods applicable to the radiation types and energies discussed in this guide, see ICRU Reports 14, 17, 34, 35 and Refs (5, 6).
4.2 This guide uses the methodology adopted by the International Organization for Standardization for estimating uncertainties in dosimetry for radiation processing (see 2.3). ASTM traditionally uses the terms of precision and bias where precision is a measure of the extent to which replicate measurements made under specified conditions are in agreement and bias is a systematic error (see ASTM Terminologies E 170 and E 456, and Practice E 177). As seen from this standard, components of uncertainty are evaluated as either Type A or Type B rather than in terms of precision and bias. Error is different from Type A and Type B components of uncertainty.
4.3 Although this guide provides a framework for assessing uncertainty, it cannot substitute for critical thinking, intellectual honesty, and professional skill. The evaluation of uncertainty is neither a routine task nor a purely mathematical one; it depends on detailed knowledge of the nature of the measurand and of the measurement method and procedure used. The quality and utility of the uncertainty quoted for the result of a measurement therefore ultimately depends on the understanding, critical analysis, and integrity of those who contribute to the a...
SCOPE
1.1 This guide defines possible sources of uncertainty in dosimetry performed in gamma, X-ray (bremsstrahlung), and electron irradiation facilities and offers procedures for estimating the resulting magnitude of the uncertainties in the measurement of absorbed dose using a dosimetry system. Basic concepts of measurement, estimate of the measured value of a quantity, "true value", error, and uncertainty are defined and discussed. Components of uncertainty are discussed and methods are given for evaluating and estimating their values. How these contribute to the standard uncertainty in the reported values of absorbed dose are considered and methods are given for calculating the combined standard uncertainty and an estimate of expanded (overall) uncertainty. The methodology for evaluating components of uncertainty follows ISO procedures (see ). The traditional concepts of precision and bias are not used in this document. Examples are given in five annexes.
1.2 This guide assumes a working knowledge of statistics. Several statistical texts are included in the references  ().
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 health practices and determine the applicability of regulatory limitations prior to use.

General Information

Status
Historical
Publication Date
14-May-2005
Technical Committee
Drafting Committee
Current Stage
Ref Project

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ASTM ISO/ASTM51707-05 - Standard Guide for Estimating Uncertainties in Dosimetry for Radiation Processing
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ISO/ASTM51707:2005(E)
An American National Standard
Standard Guide for
Estimating Uncertainties in Dosimetry for Radiation
1
Processing
This standard is issued under the fixed designation ISO/ASTM 51707; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision.
1. Scope E177Practice for Use of the Terms Precision and Bias in
ASTM Test Methods
1.1 This guide defines possible sources of uncertainty in
E178Practice for Dealing With Outlying Observations
dosimetry performed in gamma, X-ray (bremsstrahlung), and
E456Terminology Relating to Quality and Statistics
electron irradiation facilities and offers procedures for estimat-
E876Practice for Use of Statistics in the Evaluation of
ing the resulting magnitude of the uncertainties in the mea-
4
Spectrometric Data (Withdrawn 2003)
surement of absorbed dose using a dosimetry system. Basic
E1249Practice for Minimizing Dosimetry Errors in Radia-
concepts of measurement, estimate of the measured value of a
tionHardnessTestingofSiliconElectronicDevicesUsing
quantity, “true value”, error, and uncertainty are defined and
Co-60 Sources
discussed. Components of uncertainty are discussed and meth-
3
2.2 ISO/ASTM Standards:
ods are given for evaluating and estimating their values. How
51204Practice for Dosimetry in Gamma Irradiation Facili-
these contribute to the standard uncertainty in the reported
ties for Food Processing
values of absorbed dose are considered and methods are given
51205Practice for Use of a Ceric-Cerous Sulfate Dosimetry
for calculating the combined standard uncertainty and an
System
estimate of expanded (overall) uncertainty. The methodology
51261Guide for Selection and Calibration of Dosimetry
for evaluating components of uncertainty follows ISO proce-
Systems for Radiation Processing
dures (see 2.3). The traditional concepts of precision and bias
51275Practice for Use of a Radiochromic Film Dosimetry
are not used in this document. Examples are given in five
System
annexes.
51400Practice for Characterization and Performance of a
1.2 This guide assumes a working knowledge of statistics.
High-Dose Radiation Dosimetry Calibration Laboratory
2
Several statistical texts are included in the references (1-4).
51431Practice for Dosimetry in Electron Beam and X-ray
1.3 This standard does not purport to address all of the (Bremsstrahlung) Irradiation Facilities for Food Process-
safety concerns, if any, associated with its use. It is the
ing
responsibility of the user of this standard to establish appro-
2.3 ISO Documents:
priate safety and health practices and determine the applica-
ISO, 1995, ISBN 92-67-10188-9Guide to the Expression of
5
bility of regulatory limitations prior to use.
Uncertainty in Measurement
ISO 11137 Sterilization of Health Care Products-
2. Referenced documents
Requirements for Validation and Routine Control-
3
6
2.1 ASTM Standards:
Radiation Sterilization
7
E170Terminology Relating to Radiation Measurements and
2.4 ICRU Reports:
Dosimetry
ICRU Report 14Radiation Dosimetry: X Rays and Gamma
RayswithMaximumPhotonEnergiesBetween0.6and50
1
This guide is under the jurisdiction of ASTM Committee E61 on Radiation MeV
Processing and is the direct responsibility of Subcommittee E61.01 on Dosimetry,
ICRU Report 17Radiation Dosimetry: X Rays Generated at
and is also under the jurisdiction of ISO/TC 85/WG 3.
Potentials of 5 to 150 kV
Current edition approved by ASTM June 1, 2004. Published May 15, 2005.
ICRU Report 34The Dosimetry of Pulsed Radiation
Originally published as ASTM E 1707–95. Last previous ASTM edition
ε1 ε1
E1707–95 . ASTM E1707–95 was adopted by ISO in 1998 with the interme-
diate designation ISO 15572:1998(E). The present International Standard ISO/
4
ASTM 51707:2005(E) is a major revision of the last previous edition ISO/ASTM The last approved version of this historical standard is referenced on
51707:2002(E), which replaced ISO 15572. www.astm.org.
2 5
Theboldfacenumbersinparenthesesrefertothebibliographyattheendofthis Available from ISO Central Secretariat, Postal 56, 1211 Geneva 20 Switzer-
guide. land.
3 6
For referenced ASTM and ISO/ASTM standards, visit the ASTM website, Available from Association for the Advancement of Medical Instrumentation,
www.astm.org, or contact ASTM Customer Service at service@astm.org. For 1110 North Glebe Road, Suite 220, Arlington, VA 22201-4795, U.S.A.
7
Annual Book of ASTM Standards volume information, refer to the standard’s Available from International Commission on Radiation Units and
Document Summary page on the ASTM website. Measurements, 7910 Woodmont Ave., Suite 800 Bethesda, MD 20814, U.S.A.
© ISO/ASTM International 2015 – All rights reserved
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ISO/ASTM 51707:2005(E)
ICRU Report 35Radiatio
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