ISO 21439:2009

INTERNATIONAL ISO
STANDARD 21439
First edition
2009-02-15
Clinical dosimetry — Beta radiation
sources for brachytherapy
Dosimétrie clinique — Sources de radiation bêta pour curiethérapie

Reference number
©
ISO 2009
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ii © ISO 2009 – All rights reserved

Contents Page
Foreword .v
Introduction.vi
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Beta radiation sources and source data.8
4.1 Ophthalmic and dural brachytherapy sources.8
4.2 Intravascular brachytherapy sources .9
4.3 Characteristics of radionuclides.9
4.4 Source specification .9
5 Dose calculation parameters and formalisms.11
5.1 General .11
5.2 Radiation-field parameterization.12
5.3 Radial dose profile .13
5.4 Normalization of relative-dose data for seed sources.14
5.5 Adaptation of the TG-43/60 formalism for a long beta radiation line source.16
5.6 Reference data sets.17
5.7 Parameters for source uniformity characterization.17
6 Calibration and traceability .19
6.1 Measurand.19
6.2 Traceability.19
6.3 Reference point .19
6.4 Primary standards .19
6.5 Secondary standards.19
6.6 Transfer standards .19
6.7 Calibration of therapeutic beta radiation sources .20
7 Dose measurements in-phantom and measurement corrections.20
7.1 Measurements in water or a water-equivalent phantom .20
7.2 Detectors for beta radiation.21
7.3 Conversion of absorbed dose in solid phantoms to absorbed dose to water.22
7.4 Effective point of measurement in the detector.24
8 Theoretical modelling .25
8.1 Point-dose kernels .25
8.2 Monte Carlo simulation.26
9 Uncertainties in source calibrations .28
9.1 General .28
9.2 Uncertainty of primary standards.28
9.3 Uncertainty of secondary standards .28
9.4 Uncertainty of transfer standards.28
9.5 Relationship of dosimetry uncertainty to positional error.29
9.6 Uncertainty in theoretical modeling .29
10 Treatment planning and reporting.30
10.1 General .30
10.2 General aspects of treatment planning.30
10.3 Documentation in ophthalmic brachytherapy.30
10.4 Uncertainty of the dose delivered in ophthalmic brachytherapy .30
10.5 Documentation in intravascular brachytherapy.31
10.6 Reporting uncertainties in intravascular brachytherapy.33
11 Clinical quality control .33
11.1 Acceptance tests .33
11.2 Constancy checks .37
Annex A (normative) Reference data .38
Annex B (informative) Reference data sheet examples .43
Annex C (informative) Primary standards for beta radiation dosimetry.52
Annex D (informative) Detectors and phantom materials for clinical dosimetry of beta radiation
brachytherapy sources .58
Annex E (informative) Monte Carlo calculations.68
Annex F (informative) Treatment planning .77
Bibliography .82

iv © ISO 2009 – All rights reserved

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 21439 was prepared by Technical Committee ISO/TC 85, Nuclear energy, Subcommittee SC 2, Radiation
protection.
Introduction
Clinical dosimetry covers the methods by which values of the relevant physical quantity, absorbed dose to
water, can be measured at a given point by the use of calibrated instruments in a clinical setting. The
application of beta radiation sources for brachytherapy requires new and skilled methods for adequate clinical
dosimetry necessitated by the short range of the beta radiation. This causes large dose-rate gradients around
beta radiation sources, and hence it is necessary that the detector volumes for absorbed-dose measurements
be extremely small. This leads to the requirement for highly specialized detectors and calibration techniques,
and it is necessary to scrutinize closely every calibration obtained in one beta radiation field and determine if it
is applicable in another field.
It is necessary that an appropriate quality system be implemented and maintained in the hospital for clinical
beta radiation source dosimetry. It is the responsibility of the medical physicist to carry out testing and
calibration activities for any source in such a way as to meet the requirements for adequate dosimetry. This
International Standard gives guidance on how to satisfy these needs.

vi © ISO 2009 – All rights reserved

INTERNATIONAL STANDARD ISO 21439:2009(E)

Clinical dosimetry — Beta radiation sources for brachytherapy
1 Scope
This International Standard specifies methods for the determination of absorbed-dose distributions in water or
tissue that are required prior to initiating procedures for the application of beta radiation in ophthalmic tumour
[1], [2], [3]
and intravascular brachytherapy . Recommendations are given for beta radiation source calibration,
dosimetry measurements, dose calculation, dosimetric quality assurance, as well as for beta radiation
brachytherapy treatment planning. Guidance is also given for estimating the uncertainty of the absorbed dose
to water. This International Standard is applicable to “sealed” radioactive sources, such as plane and concave
surface sources, source trains of single seeds, line sources, and shell and volume sources, for which only the
beta radiation emitted is of therapeutic relevance.
The standardization of procedures in clinical dosimetry described in this International Standard serves as a
basis for the reliable application of beta radiation brachytherapy. The specific dosimetric methods described in
this International Standard apply to sources for the curative treatment of ophthalmic disease, for intravascular
brachytherapy treatment, for overcoming the problem of restenosis and for other clinical applications using
beta radiation.
This International Standard is geared towards organizations wishing to establish reference methods in
dosimetry aiming at clinical demands for an appropriately small uncertainty of the delivered dose. This
Interna
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