ISO/ASTM 51939:2013

Practice for blood irradiation dosimetry

ISO/ASTM 51939:2013 outlines irradiator installation qualification, operational qualification, performance qualification and routine product processing dosimetric procedures to be followed in the irradiation of blood and blood components by the blood-banking community. If followed, these procedures will help to ensure that the products processed with ionizing radiation from gamma, X-radiation (bremsstrahlung), or electron sources receive absorbed doses within a predetermined range. ISO/ASTM 51939:2013 covers dosimetry for the irradiation of blood for these types of irradiators: self-contained irradiators (free-standing irradiators) utilizing 137Cs, 60Co or X-radiation (bremsstrahlung), teletherapy units, and electron accelerators. ISO/ASTM 51939:2013 also covers the use of radiation-sensitive indicators for the visual and qualitative indication that the product has been irradiated.

Pratique de la dosimétrie pour l'irradiation du sang

General Information

• Status: Withdrawn
• Publication Date: 30-Sep-2013
• Withdrawal Date: 30-Sep-2013
• ICS: 11.020 - Medical sciences and health care facilities in general
• ICS: 11.020.99 - Other standards related to health care in general
• ICS: 17.240 - Radiation measurements
• Technical Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Drafting Committee: ISO/TC 85 - Nuclear energy, nuclear technologies, and radiological protection
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 06-Mar-2017

Relations

• Revised: ISO/ASTM 51939:2017 - Practice for blood irradiation dosimetry
• Effective Date: 26-Mar-2016
• Revises: ISO/ASTM 51939:2005 - Practice for blood irradiation dosimetry
• Effective Date: 02-Mar-2013

Standards Content (Sample)

ISO/ASTM
51939
Third edition
2013-10-01

Practice for blood irradiation dosimetry
Pratique de la dosimétrie pour l'irradiation du sang




Reference number
ISO/ASTM 51939:2013(E)

©
ISO/ASTM International 2013

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ISO/ASTM 51939:2013(E)

©  ISO/ASTM International 2013
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
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Published in Switzerland

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ISO/ASTM 51939:2005(Reapproved 2013)(E)
Contents Page
1 Scope . 1
2 Referenced Documents . 1
3 Terminology . 1
4 Significance and use . 3
5 Type of facilities and modes of operation used for blood irradiation . 4
6 Radiation source characteristics . 4
7 Dosimetry systems . 4
8 Installation qualification . 6
9 Operational qualification . 7
10 Performance qualification . 8
11 Routine product processing . 9
12 Measurement uncertainty . 9
13 Keywords . 10
Annexes . 10
Bibliography . 12
Table 1 Examples of reference-standard dosimeters . 5
Table 2 Examples of transfer-standard dosimeters . 5
Table 3 Examples of routine dosimeters . 5
Table A2.1 Recommended quality assurance steps for blood irradiation . 12
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ISO/ASTM FDIS 51939:2005(Reapproved 2013)(E)
ISO/ASTM 51939:2005(Reapproved 2013)(E)
Foreword
ISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are circulated to the member bodies for
voting. Publication as an International Standard requires approval by at least 75% of the member bodies
casting a vote.
ASTM International is one of the world’s largest voluntary standards development organizations with global
participation from affected stakeholders. ASTM technical committees follow rigorous due process balloting
procedures.
A project between ISO and ASTM International has been formed to develop and maintain a group of
ISO/ASTMradiationprocessingdosimetrystandards.Underthisproject,ASTMSubcommitteeE61,Radiation
Processing, is responsible for the development and maintenance of these dosimetry standards with
unrestricted participation and input from appropriate ISO member bodies.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. Neither ISO nor ASTM International shall be held responsible for identifying any or all such patent
rights.
International Standard ISO/ASTM 51939 was developed by ASTM Committee E61, Radiation Processing,
through Subcommittee E61.04, Specialty Application, and by Technical Committee ISO/TC 85, Nuclear
energy, nuclear technologies and radiological protection.
This third edition cancels and replaces the second edition (ISO/ASTM 51939:2005).
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ISO/ASTM 51939:2005(Reapproved 2013)(E)
An American National Standard
Standard Practice for
1
Blood Irradiation Dosimetry
This standard is issued under the fixed designation ISO/ASTM 51939; 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 51275 Practice for Use of a Radiochromic Film Dosimetry
System
1.1 This practice outlines irradiator installation qualifica-
51310 Practice for Use of a Radiochromic Optical Wave-
tion, operational qualification, performance qualification, and
guide Dosimetry System
routine product processing dosimetric procedures to be fol-
51400 Practice for Characterization and Performance of a
lowed in the irradiation of blood and blood components by the
High-Dose Radiation Dosimetry Calibration Laboratory
blood-banking community. If followed, these procedures will
51538 Practice for Use of the Ethanol-Chlorobenzene Do-
help to ensure that the products processed with ionizing
simetry System
radiation from gamma, X-radiation (bremsstrahlung), or elec-
51539 Guide for the Use of Radiation-Sensitive Indicators
tron sources receive absorbed doses within a predetermined
51607 Practice for Use of the Alanine-EPR Dosimetry
range.
System
1.2 This practice covers dosimetry for the irradiation of
51608 Practice for Dosimetry in an X-ray (Bremsstrahlung)
blood for these types of irradiators: self-contained irradiators
137 60
Facility for Radiation Processing
(free-standing irradiators) utilizing Cs, Co or X-radiation
51707 Guide for Estimating Uncertainties in Dosimetry for
(bremsstrahlung), teletherapy units, and electron accelerators.
Radiation Processing
The absorbed dose range for blood irradiation is typically 15
51956 Practice for Thermoluminescent Dosimetry (TLD)
Gyto50Gy.Insomejurisdictions,theabsorbeddoserangefor
for Radiation Processing
blood irradiation is 25 Gy to 50 Gy.
52116 Practice for Dosimetry for a Self-Contained Dry-
1.3 The energy range is typically from approximately 40
Storage Gamma-Ray Irradiator
keV to 5 MeV for photons, and up to 10 MeV for electrons.
2.3 International Commission on Radiation Units and
1.4 This practice also covers the use of radiation-sensitive
3
Measurements Reports (ICRU):
indicators for the visual and qualitative indication that the
ICRU 85 Fundamental Quantities and Units for Ionizing
product has been irradiated.
Radiation
1.5 This standard does not purport to address all of the
2.4 Guidelines on Blood Irradiation:
safety concerns, if any, associated with its use. It is the
Guidelines on Gamma Irradiation of Blood Components for
responsibility of the user of this standard to establish appro-
the Prevention of Transfusion-associated Graft-versus-
priate safety and health practices and to determine the
host Disease, Prepared by the BCSH Blood Transfusion
applicability or regulatory limitations prior to use.
4
Task Force
2. Referenced Documents
Recommendations Regarding License Amendments and
2
Procedures for Gamma Irradiation of Blood Products,
2.1 ASTM Standards:
5
(1993) US Food and Drug Administration
E170 Terminology Relating to Radiation Measurements
Guidance for Industry, Gamma Irradiation of Blood and
and Dosimetry
BloodComponents:APilotProgramforLicensing(2000)
E1026 Practice for Using the Fricke Reference Standard
5
US Food and Drug Administration
Dosimetry System
E2304 Practice for Use of a LiF Photo-Fluorescent Film
3. Terminology
Dosimetry System
2
3.1 Definitions:
2.2 ISO/ASTM Standards:
3.1.1 absorbed dose (D)—quantity of ionizing radiation
51261 Practice for Calibration of Routine Dosimetry Sys-
energy imparted per unit mass of a specified material. The SI
tems for Radiation Processing
unit of absorbed dose is the gray (Gy), where 1 gray is
equivalent to the absorption of 1 joule per kilogram of the
1
specified material (1 Gy = 1 J/kg). The mathematical relation-
This practice is under the jurisdiction of ASTM Committee E61 on Radiation
Processing and is the direct responsibility of Subcommittee E61.04 on Specialty
ship is the quotient of dϵ by dm, where dϵ is the mean
Application, and is also under the jurisdiction of ISO/TC 85/WG 3.
Current edition approved byASTM Jan. 1, 2013. Published XX, XX. Originally
published as ASTM E 1939–98. Last previous ASTM edition E 1939–98. The
3
presentInternationalStandardISO/ASTM51939:2005(20XX)(E)isareapprovalof AvailablefromtheInternationalCommissiononRadiationUnitsandMeasure-
the last previous edition ISO/ASTM 51939:2005:(E). ments, 7910 Woodmont Ave., Suite 800, Bethesda, MD 20814 U.S.A.
4
2
For referenced ASTM and ISO/ASTM standards, visit the ASTM website, Available from the National Blood Transfusion Service, East Anglian Blood
www.astm.org, or contact ASTM Customer Service at [e-mail]. For Transfusion Centre, Long Road, Cambridge, CB2 2PT United Kingdom.
5
Annual Book of ASTM Standards volume information, refer to the standard’s Available from the Office of Communication, Training and Manufacturers
Document Summary page on the ASTM website. Assistance (HFM-40), 1401 Rockville Pike, Rockville, MD 20852-1488, USA.
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ISO/ASTM 51939:2005(Reapproved 2013)(E)
incremental energy imparted by ionizing radiation to matter of 3.1.11 dosimetry system—system used for determining ab-
incremental mass dm (see ICRU85). sorbed dose, consisting of dosimeters, measurement instru-
mentsandtheirassociatedreferencestandards,andprocedures
D 5d´¯ dm (1)
/
for the system’s use.
3.1.1.1 Discussion—The discontinued unit for absorbed
3.1.12 installation qualification (IQ)—obtaining and docu-
dose is the rad (1 rad = 100 erg/g = 0.01 Gy). Absorbed dose
menting evidence that the irradiator, with all its associated
is sometimes referred to simply as dose.
equipment and instrumentation, has been provided and in-
˙
3.1.2 absorbed-dose rate (D)—absorbed dose in a material
stalled in accordance with specifications.
per incremental time interval, that is, the quotient of dD by dt.
3.1.13 instrument traceability—abilitytodemonstratethata
˙
measurementinstrumenthasbeencalibratedatacceptabletime
D 5dD dt (2)
/
intervals against a national or international standard or against
–1
Unit: Gy·s .
asecondarystandardthathasbeencalibratedagainstanational
3.1.3 absorbed-dose mapping—measurement of absorbed
or international standard.
dose within product using dosimeters placed at specified
3.1.14 irradiator sample chamber—accessible enclosed
locations to produce a one, two, or three-dimensional distribu-
volume in which a sample or sample holder may be placed in
tion of absorbed dose, thus rendering a map of absorbed-dose
the loading/unloading position of the irradiator (typically a
values.
gamma cell) prior to irradiation, and which can be transported
3.1.4 activity (A) (of an amount of radioactive nuclide in a
by the sample positioning system to the irradiation position.
particular energy state at a given time)—quotient of dN by dt,
3.1.15 irradiator turntable—device used to rotate the irra-
where dN is the expectation value of the number of spontane-
diated sample during the irradiation process so as to improve
ous nuclear transitions from that energy state in the time
dose uniformity ratio.
interval dt (see ICRU85).
3.1.15.1 Discussion—An irradiator turntable is often re-
A 5dN/dt (3)
ferred to as a turntable. Some irradiator geometries, for
−1
Unit: s example with a circular array of radiation sources surrounding
The special name for the unit of activity is the becquerel the product, may not need a turntable.
−1
(Bq). 1 Bq=1s .
3.1.16 isodose curve—lines or surfaces of constant ab-
3.1.4.1 Discussion—The former special unit of activity was
sorbed dose through a specified medium.
10 −1
the curie (Ci). 1 Ci = 3.7 3 10 s (exactly).
3.1.17 measurement quality assurance plan—documented
3.1.5 blood and blood components—include whole blood, program for the measurement process that ensures on a
redcells,frozencells,plateletconcentrates,apheresisplatelets,
continuing basis that the overall uncertainty meets the require-
granulocyte concentrates, and fresh or frozen plasma. mentsofthespecificapplication.Thisplanrequirestraceability
3.1.5.1 Discussion—Enclosuresystemsforbloodandblood to, and consistency with, nationally or internationally recog-
components are commonly referred to as “bags.” The volume nized standards.
of a typical blood bag is less than 0.5 L. Blood and blood 3.1.18 measurement traceability—ability to demonstrate by
components are often referred to as blood product.
means of an unbroken chain of comparisons that a measure-
3.1.6 calibration—set of operations under specified condi- ment is in agreement within acceptable limits of uncertainty
tions, which establishes the relationship between values indi- with comparable nationally or internationally recognized stan-
cated by a measuring instrument or measuring system, and the dards.
corresponding values realised by standards traceable to a
3.1.19 operational qualification (OQ)—obtaininganddocu-
nationally or internationally recognized laboratory.
mentingevidencethatinstalledequipmentandinstrumentation
3.1.7 canister—container, usually an aluminum or steel
operate within predetermined limits when used in accordance
cylinder, used to house the blood product, or blood-equivalent with its operational procedures.
product during the irradiation process.
3.1.20 performance qualification (PQ)—obtaining and
3.1.8 dose uniformity ratio—ratioofmaximumtominimum
documentingevidencethattheequipmentandinstrumentation,
absorbed dose within the irradiated blood or blood product. as installed and operated in accordance with operational
This concept is also referred to as the “max/min ratio.”
procedures, consistently perform according to predetermined
3.1.9 dosimeter—device that, when irradiated, exhibits a criteria and thereby yield product that meets specifications.
quantifiable change in some property of the device which can 3.1.21 radiation-sensitive indicator—material such as a
be related to absorbed dose in a given material using appro-
coated or impregnated adhesive-backed substrate, ink, coating
priate analytical instrumentation and techniques. or other material which may be affixed to or printed on the
3.1.9.1 Discussion—Adosimetermustexhibitthereproduc- productandwhichundergoesavisualchangewhenexposedto
ible and quantifiable properties that allow it to be calibrated ionizing radiation.
and compared to national standards.
3.1.21.1 Discussion—Radiation-sensitive indicators are of-
3.1.10 dosimeter batch—quantity of dosimeters made from ten referred to as “indicators.” Radiation-sensitive indicators
a specific mass of material with uniform composition, fabri- cannot be classified as a “label” under the U.S. FDA “Guide-
cated in a single production run under controlled, consistent lines for the Uniform Labeling of Blood and Blood Products”
5
conditions and having a unique identification code. (August, 1985). Indicators may be used to show that products
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ISO/ASTM 51939:2005(Reapproved 2013)(E)
have been exposed to ionizing radiation. They can be used to 4.2 Blood and blood components are irradiated at pre-
provide a visual and qualitative indication of radiation expo-
determined doses to inactivate viable lymphocytes to help
sure and can be used to distinguish between irradiated blood
preventtransfusion-inducedgraft-versus-hostdisease(GVHD)
and blood components and non-irradiated blood and blood
in certain immunocompromised patients and those receiving
6
components. Indicators cannot be used as a substitute for
related-donor products (1, 2).
proper dosimetry.
4.3 Blood and blood components may be treated with
3.1.22 reference-standard dosimeter—dosimeter of high 137 60
ionizingradiation,suchasgammaradiationfrom Csor Co
metrological quality used as a standard to provide measure-
sources, and from self-contained X-ray (bremsstrahlung) units
ments traceable to measurements made with primary-standard
and medical linear X-ray (bremsstrahlung) and electron accel-
dosimeters.
erators used primarily for radiotherapy.
3.1.23 routine dosimeter—dosimeter calibrated against a
4.3.1 The terms “gamma rays” and “gamma radiation” are
primary-, reference-, or transfer-standard dosimeter and used
used interchangeably, as are the terms “X-ray” and “X-
for routine absorbed-dose measurement.
radiation.”
3.1.24 simulated product—material with radiation attenua-
tion and scattering properties similar to those of the product, 4.4 Blood irradiation specifications include a lower limit of
material or substance to be irradiated. absorbeddose,andmayincludeanupperlimitorcentraltarget
3.1.24.1 Discussion—Simulated product is used during ir-
dose. For a given application, any of these values may be
radiator characterization as a substitute for the actual product,
prescribed by regulations that have been established on the
materialorsubstancetobeirradiated.Whenusedforabsorbed-
basis of available scientific data. See 2.4.
dose mapping, simulated product is sometimes referred to as
4.5 For each blood irradiator, an absorbed-dose rate at a
phantom material.
reference position within the canister is measured by the
3.1.25 transfer-standard dosimeter—dosimeter, often a
manufacturer as part of acceptance testing using a reference-
reference-standard dosimeter, suitable for transport between
standard dosimetry system. That reference-standard measure-
different locations, used to compare absorbed-dose measure-
ment is used to calculate the timer setting required to deliver
ments.
the specified absorbed dose to the center of the canister with
3.1.26 transit dose—absorbed dose delivered to a product
blood and blood components, or other reference position.
(or a dosimeter) while it travels between the non-irradiation
Either relative or absolute absorbed-dose measurements are
position and the irradiation position, or in the case of a
performed within the blood- or blood-equivalent volume for
movable source while the source moves into and out of its
determining the absorbed-dose distribution.Accurate radiation
irradiation position.
dosimetryatareferencepositionwhichcouldbethepositionof
3.1.27 validation—establishment of documented evidence,
the maximum absorbed dose (D ) or minimum absorbed
which provides a high degree of assurance that a specified max
dose (D ) offers a quantitative, independent method to
min
process will consistently produce a product meeting its prede-
monitor the radiation process.
termined specifications and quality attributes.
3.1.28 X-radiation (bremsstrahlung)—common name for 4.6 Dosimetry is part of a measurement quality assurance
the short-wavelength electromagnetic radiation. The term in-
program that is applied to ensure that the radiation process
cludes both broad-spectrum bremsstrahlung (emitted when an
meets predetermined specifications (3).
energeticelectronisinfluencedbyastrongelectricormagnetic
4.7 Absorbed-dose mapping is often performed using simu-
field, such as that in the vicinity of an atomic nucleus) and the
lated product (for example, polystyrene is considered blood
characteristic monoenergetic radiation (emitted when atomic 137
equivalent for Cs photon energies).
electrons make transitions to more tightly bound states).
4.8 Blood and blood components are usually chilled or
3.1.29 X-ray (bremsstrahlung) converter—device for gen-
frozen. Care should be taken, therefore, to ensure that the
erating X-radiation (bremsstrahlung) from an electron beam,
dosimetersandradiation-sensitiveindicatorscanbeusedunder
consisting of a target, means for cooling the target, and a
such temperature conditions.
supporting structure.
4.9 Proper documentation and record keeping are critical
3.2 Definitions of other terms used in this standard that
components of radiation processing. This standard does not
pertain to radiation measurement and dosimetry may be found
address this issue since the pertinent governing bodies set
in ASTM Terminology E170E170. Definitions in ASTM
Terminology E170E170 are compatible with ICRU85; that minimum requirements.
document, therefore, may be used as an alternative reference.
4.10 Mostdosimetershavesignificantenergydependenceat
photon and electron energies less than 100 keV, so great care
4. Significance and use
must be exercised when measuring absorbed dose in that
4.1 The assurance that blood and blood components have
energy range.
been properly irradiated is of crucial importance for patient
health. The irradiator operator must demonstrate by means of
accurate absorbed-dose measurements on the product, or in
6
simulated product, that the specified absorbed dose has been
Theboldfacenumbersinparenthesesrefertothebibliographyattheendofthis
standard.
achieved throughout the product.
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ISO/ASTM 51939:2005(Reapproved 2013)(E)
5. Type of facilities and modes of operation used for 5.3.3 Spectrum filtration is used to reduce the low energy
blood irradiation component of the X-radiation, thus improving the dose unifor-
mity.
5.1 Self-Contained Blood Irradiators—Self-contained irra-
137 60
diators may utilize gamma radiation from either Cs or Co
6. Radiation source characteristics
(4), or low energy X-radiation (bremsstrahlung). Units with
6.1 The source of radiation used in a facility considered in
60 137
radionuclides house the radiation source in a protective lead
this practice consists of sealed Co or Cs sources that are
shield (or other appropriate high atomic number material), and
typically linear rods arranged in one or more planar or
usually have a mechanism to move the canister from the
cylindrical arrays, X-radiation (bremsstrahlung), or electrons.
load/unloadpositiontotheirradiationposition.Typically,units
6.2 Cobalt-60emitsphotonswithenergiesofapproximately
with low-energy X-radiation (bremsstrahlung) require less
1.17 and 1.33 MeV in nearly equal proportions. Cesium-137
shielding relative to units utilizing gamma radiation. In some
produces photons with energies of approximately 0.662 MeV
cases, irradiator turntables are used.
(5).
60 137
5.1.1 The most common method used to ensure a uniform 6.3 The half-lives for Co and Cs are approximately
5.2708 years (6) and 30.07 years (7, 8), respectively.
absorbed-dose distribution in the blood product is to rotate the
canister holding the blood product on an irradiator turntable in 6.4 For gamma sources, the only variation in the source
output is the known reduction in the activity caused by
front of the radiation source.
radioactive decay. The reduction in the source output and the
5.1.2 Asecondmethodistodistributeanumberofradiation
required increase in the irradiation time to deliver the same
sources in a circular array. The blood product is located at the
dose may be calculated (see 9.3.4) or obtained from tables
center of the array where the absorbed-dose distribution is
provided by the irradiator manufacturer.
relatively uniform. In this design, irradiator turntables would
6.5 Direct-action electron accelerators, which employ dc or
not normally be necessary.
pulsed high-voltage generators, typically produce electron
60
5.2 Teletherapy Equipment— Co equipment and linear
energies up to 5 MeV. Indirect-action electron accelerators use
accelerator teletherapy equipment (in electron or X-rays
microwave or very high frequency (vhf) ac power to produce
(bremsstrahlung)mode)areusedprimarilyforthetreatmentof
electron energies typically from 5 MeV to 15 MeV.
tumors. These units may also be used to irradiate blood and
6.6 The continuous energy spectrum of the X-radiation
bloodcomponents.Inbothtypesofequipment,theradiationis
(bremsstrahlung) ranges from approximately 40 keV up to the
directed at the blood and blood components using a collimator
maximum energy of the electrons incident on the X-ray
that creates a well-defined beam of radiation. The blood
(bremsstrahlung) target (see ISO/ASTM Practice 51608).
productisplacedintheradiationbeamandirradiatedstatically
6.7 Regulations in some countries limit the maximum elec-
(that is, neither the source nor the blood product move relative
tron energy to 10 MeV and photon energy to 5 MeV for
to one another during irradiation).
radiation treatment.
5.3 Electron Accelerator (Electron and X-ray (bremsstrahl-
7. Dosimetry systems
ung) Modes)—Accelerator-generated radiation is in the form
7.1 Description of Dosimeter Classes:
of electrons or X-radiation (bremsstrahlung). Teletherapy ac-
7.1.1 Dosimeters may be divided into four basic classes
celerators can be used for this purpose. The blood product is
according to their relative quality and areas of application:
placed in the radiation beam and irradiated statically (that is,
primary-standard, reference-standard, transfer-standard, and
neither the source nor the blood product move relative to one
routine dosimeters. ISO/ASTM Guide 51261 provides infor-
another during irradiation).
mation about the selection of dosimetry systems for different
5.3.1 An electron accelerator emits high-energy electrons.
applications. All classes of dosimeters, except the primary
Thetwoprincipalbeamcharacteristicsaretheenergyspectrum
standards, require calibration before their use.
and the average beam current. The electron energy spectrum
7.1.1.1 Primary-Standard Dosimeters—Primary-standard
affects the variation of absorbed dose with depth in a given
dosimeters are established and maintained by national stan-
material, and the average beam current affects the absorbed-
dards laboratories for calibration of radiation environments
dose rate.
(fields) and other classes of dosimeters. The two most com-
5.3.2 An X-ray (bremsstrahlung) accelerator or generator
monly used primary-standard dosimeters are ionization cham-
emits short-wavelength electromagnetic radiation, which is
bers and calorimeters.
analogous to gamma radiation from radioactive sources. Al-
7.1.1.2 Reference-Standard Dosimeters—Reference-
though their effects on irradiated materials are generally
standard dosimeters are used to calibrate radiation environ-
similar, these kinds of radiation differ in their energy spectra,
ments and routine dosimeters. Reference-standard dosimeters
angular distribution, and dose rates. The physical characteris-
mayalsobeusedasroutinedosimeters.Examplesofreference-
tics of the X-radiation (bremsstrahlung) field depend on the
standard dosimeters, along with their useful dose ranges, are
design of the X-rays (bremsstrahlung) converter and the given in ISO/ASTM Guide 51261 and Table 1.
parameters of the electron beam striking the target, that is, the
7.1.1.3 Transfer-Standard Dosimeters—Transfer-standard
electron energy spectrum, average electron beam current, and dosimeters are specially selected dosimeters used for transfer-
beam current distribution on the target. ring absorbed-dose information from an accredited or national
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ISO/ASTM 51939:2005(Reapproved 2013)(E)
TABLE 1 Examples of reference-standard dosimeters
Useful Absorbed-dose
Dosimeter Readout System Reference
Range (Gy)
5
Alanine EPR Spectrometer 1 to 10 ISO/ASTM 51607
6
Ethanol-Chlorobenzene solution Spectrophotometer, color titration, high 10 to 2 3 10 ISO/ASTM 51538
frequency conductivity
Fricke UV Spectrophotometer 20 to 400 ASTM E 1026E 1026
Ionization Chamber Electrometer Can be easily applied to the blood-irradiation (9)
A
Dose Range
A
In principle, an ion chamber can be used to make absolute absorbed-dose rate measurements at any dose rate. In the blood-irradiation dose-rate range (for example,
5 to 20 Gy/min), the ion chamber will perform satisfactorily i
...