SIST EN ISO 16637:2019

SLOVENSKI STANDARD
01-september-2019
Radiološka zaščita - Nadzorovanje in notranja dozimetrija za člane osebja,
izpostavljene medicinskim radionuklidom kot odprtemu viru sevanja (ISO
16637:2016)
Radiological protection - Monitoring and internal dosimetry for staff members exposed to
medical radionuclides as unsealed sources (ISO 16637:2016)
Strahlenschutz - Überwachung und interne Dosimetrie für Personal, das durch
medizinische Radionuklide aus offenen Quellen exponiert wurde (ISO 16637:2016)
Radioprotection - Surveillance et dosimétrie interne des travailleurs exposés lors des
utilisations médicales des radioéléments en sources non scellées (ISO 16637:2016)
Ta slovenski standard je istoveten z: EN ISO 16637:2019
ICS:
13.280 Varstvo pred sevanjem Radiation protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 16637
EUROPEAN STANDARD
NORME EUROPÉENNE
June 2019
EUROPÄISCHE NORM
ICS 13.280
English Version
Radiological protection - Monitoring and internal
dosimetry for staff members exposed to medical
radionuclides as unsealed sources (ISO 16637:2016)
Radioprotection - Surveillance et dosimétrie interne Strahlenschutz - Überwachung und interne Dosimetrie
des travailleurs exposés lors des utilisations médicales für Personal, das durch medizinische Radionuklide aus
des radioéléments en sources non scellées (ISO offenen Quellen exponiert wurde (ISO 16637:2016)
16637:2016)
This European Standard was approved by CEN on 8 March 2019.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16637:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 16637:2016 has been prepared by Technical Committee ISO/TC 85 "Nuclear energy,
nuclear technologies, and radiological protection” of the International Organization for Standardization
(ISO) and has been taken over as EN ISO 16637:2019 by Technical Committee CEN/TC 430 “Nuclear
energy, nuclear technologies, and radiological protection” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by December 2019, and conflicting national standards
shall be withdrawn at the latest by December 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 16637:2016 has been approved by CEN as EN ISO 16637:2019 without any modification.

INTERNATIONAL ISO
STANDARD 16637
First edition
2016-02-15
Radiological protection — Monitoring
and internal dosimetry for staff
members exposed to medical
radionuclides as unsealed sources
Radioprotection — Surveillance et dosimétrie interne des travailleurs
exposés lors des utilisations médicales des radioéléments en sources
non scellées
Reference number
ISO 16637:2016(E)
©
ISO 2016
ISO 16637:2016(E)
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior
written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of
the requester.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

ISO 16637:2016(E)
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Symbols and abbreviated terms . 5
5 Purpose and need for monitoring programmes in nuclear medical diagnosis and therapy 6
5.1 General . 6
5.2 Assessment of the level of likely exposures . 6
5.3 Monitoring programmes . 7
5.3.1 General. 7
5.3.2 Confirmatory monitoring programmes . 7
5.3.3 Routine monitoring programmes. 8
5.3.4 Triage monitoring programmes . 8
5.3.5 Task-related monitoring programmes . 8
5.3.6 Special monitoring programmes . 8
5.3.7 Implementation of a monitoring programme. 9
6 Common radionuclides .10
7 Reference levels .10
8 Routine monitoring programmes .11
8.1 General aspects .11
8.2 Individual monitoring .12
8.3 Methods and monitoring intervals .12
9 Triage monitoring programmes .13
10 Special Monitoring programmes .13
10.1 General aspects .13
10.2 Workplace monitoring . .14
10.3 Individual monitoring .14
11 Confirmatory monitoring programmes .15
11.1 General aspects .15
11.2 Workplace monitoring . .15
11.3 Individual monitoring .15
12 Measurement techniques and performance criteria .15
12.1 General .15
12.2 Measurements performed in a laboratory specialised for radiobioassay .16
12.2.1 In vitro.16
12.2.2 In vivo .16
12.2.3 Quality assurance and quality control for bioassay laboratories .16
12.3 Measurements performed in nuclear medicine service .17
13 Procedure for the assessment of exposures .17
13.1 Interpretation of individual monitoring data for dose assessment .17
13.1.1 General.17
13.1.2 Dose assessment based on routine monitoring .17
13.1.3 Dose assessment based on special monitoring .17
13.2 Software tools .22
13.3 Uncertainties .22
13.4 Quality assurance of the assessment process .22
14 Reporting and documentation .23
ISO 16637:2016(E)
14.1 Reporting results for in vitro measurements .23
14.2 Reporting results for in vivo measurements .23
14.3 Documentation of the dose assessment .24
Annex A (informative) IAEA Safety Guide RS-G-1.2 “decision factor” .25
Bibliography .27
iv © ISO 2016 – All rights reserved

ISO 16637:2016(E)
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 85, Nuclear energy, nuclear technologies, and
radiological protection, Subcommittee SC 2, Radiological protection.
ISO 16637:2016(E)
Introduction
In the course of employment, individuals might work with radioactive materials that, under certain
circumstances, could be taken into the body. Protecting workers against risks of incorporated
radionuclides requires the monitoring of potential intakes and/or the quantification of actual intakes
and exposures. The doses resulting from internal radiation exposure arising from contamination
by radioactive substances cannot be measured directly. The selection of measures and programmes
for this purpose requires decisions concerning methods, techniques, frequencies, etc. for activity
measurements and dose assessment. The criteria permitting the evaluation of the necessity of such a
monitoring programme or for the selection of methods and frequencies of monitoring usually depend
upon the legislation, the purpose of the radiation protection programme, the probabilities of potential
radionuclide intakes, and the characteristics of the materials handled.
For these reasons, ISO standards establishing requirements for monitoring programmes (ISO 20553),
laboratory requirements (ISO 28218), and dose assessment (ISO 27048) have been developed. These can
be applied in a straightforward manner to many workplaces where internal contamination may occur.
In order to apply these standards to staff involved in diagnostic or therapeutic uses of radionuclides
in medicine, the short effective half-life of radionuclides commonly used for these purposes and the
distance between nuclear medicine department and in vivo counting facilities or radio-analytical
laboratories shall be taken into account. Consequently, guidance on the application of the three
International Standards cited above to nuclear medicine staff was requested by a number of countries.
This International Standard establishes criteria to determine whether intake monitoring is required
for staff exposed to medical radionuclides as unsealed sources. It also establishes requirements on the
design of such monitoring programmes, associated dose assessments, and laboratory requirements.
Recommendations of international expert bodies and international experience with the practical
application of these recommendations in radiological protection programmes have been considered in
the development of this International Standard. Its application facilitates the exchange of information
between authorities, supervisory institutions, and employers. This International Standard is not a
substitute for legal requirements.
vi © ISO 2016 – All rights reserved

INTERNATIONAL STANDARD ISO 16637:2016(E)
Radiological protection — Monitoring and internal
dosimetry for staff members exposed to medical
radionuclides as unsealed sources
1 Scope
This International Standard specifies the minimum requirements for the design of professional
programmes to monitor workers exposed to the risk of internal contamination via inhalation by
the use of radionuclides as unsealed sources in nuclear medicine imaging and therapy departments.
It establishes principles for the development of compatible goals and requirements for monitoring
programmes and, when adequate, dose assessment. It presents procedures and assumptions for the risk
analysis, for the monitoring programmes, and for the standardized interpretation of monitoring data.
This International Standard addresses the following items:
a) purposes of monitoring and monitoring programmes;
b) description of the different categories of monitoring programmes;
c) quantitative criteria for conducting monitoring programmes;
d) suitable methods for monitoring and criteria for their selection;
e) information that has to be collected for the design of a monitoring programme;
f) general requirements for monitoring programmes (e.g. detection limits, tolerated uncertainties);
g) frequencies of measurements;
h) procedures for dose assessment based on reference levels for routine and special monitoring
programmes;
i) assumptions for the selection of dose-critical parameter values;
j) criteria for determining the significance of individual monitoring results;
k) interpretation of workplace monitoring results;
l) uncertainties arising from dose assessments and interpretation of bioassays data;
m) reporting/documentation;
n) quality assurance.
This International Standard does not address the following:
— monitoring and internal dosimetry for the workers exposed to laboratory use of radionuclides such
as radioimmunoassay techniques;
— monitoring and internal dosimetry for the workers involved in the operation, maintenance, and
servicing of PET cyclotrons;
— detailed descriptions of measuring methods and techniques;
— dosimetry for litigation cases;
— modelling for the improvement of internal dosimetry;
ISO 16637:2016(E)
— the potential influence of medical treatment of the internal contamination;
— the investigation of the causes or implications of an exposure;
— dosimetry for ingestion exposures and for contaminated wounds.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 20553, Radiation protection — Monitoring of workers occupationally exposed to a risk of internal
contamination with radioactive material
ISO 27048:2011, Radiation protection — Dose assessment for the monitoring of workers for internal
radiation exposure
ISO 28218, Radiation protection — Performance criteria for radiobioassay
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC Guide 99, ISO 20553,
ISO 28218 and ISO 27048 and the following apply.
3.1
absorption
movement of material to blood regardless of mechanism, generally applied to dissociation of particles
and uptake into blood of soluble substances and material dissociated from particles
3.2
absorption type F
as defined by ICRP, deposited materials that have high (fast) rates of absorption (3.1) into body fluids
from the respiratory tract
3.3
absorption type M
as defined by ICRP, deposited materials that have intermediate (moderate) rates of absorption (3.1) into
body fluids from the respiratory tract
3.4
activity
number of spontaneous nuclear transformations per unit time
Note 1 to entry: The activity is stated in becquerel (Bq), i.e. the number of transformations per second.
3.5
activity median aerodynamic diameter
AMAD
value of aerodynamic diameter such that 50 % of the airborne activity (3.4) in a specified aerosol is
associated with particles smaller than the AMAD, and 50 % of the activity is associated with particles
larger than the AMAD
Note 1 to entry: The aerodynamic diameter of an airborne particle is the diameter that a sphere of unit density
would need to have in order to have the same terminal velocity when settling in air as the particle of interest.
2 © ISO 2016 – All rights reserved

ISO 16637:2016(E)
3.6
contamination
activity (3.4) of radionuclides present on surfaces, or within solids, liquids or gases (including the
human body), where the presence of such radioactive material is unintended or undesirable
3.7
decision threshold
fixed value of the measurand by which, when exceeded by the result of an actual measurement of a
measurand quantifying a physical effect, it is decided that the physical effect is present
3.8
detection limit
smallest true value of the measurand which is detectable by the measuring method
3.9
annual dose
committed effective dose (3.11) resulting from all intakes (3.14) occurring during a calendar year
Note 1 to entry: The term “annual dose” is not used to represent the dose received in a year from all preceding
intakes.
3.10
committed equivalent dose
sum of the products of the total doses absorbed by an organ or a tissue from radiation types, integrated
over the commitment period following the intake (3.14) of a radionuclide, and the appropriate radiation
weighting factors
3.11
committed effective dose
sum of the products of the committed organ or tissue equivalent doses and the appropriate tissue
weighting factors
Note 1 to entry: In the context of this International Standard, the commitment period [integration time following
the intake (3.14)] is taken to be 50 years.
3.12
excretion function
function describing the fraction of an intake (3.14) excreted per day after a given time has elapsed since
the intake occurred
3.13
event = incident
any unintended occurrence, including operating error, equipment failure or other mishap, the
consequences or potential consequences of which are not negligible from the point of view of protection
or safety
3.14
intake
activity (3.4) of a radionuclide taken into the body in a given time period or as a result of a given event
3.15
in vitro analyses
indirect measurements
analyses including measurements of radioactivity present in biological samples taken from an
individual
Note 1 to entry: These include urine, faeces, and nasal samples; in special monitoring programmes (3.21), samples
of other materials, such as blood and hair, may be taken.
ISO 16637:2016(E)
3.16
in vivo measurements
direct measurements
measurement of radioactivity present in the human body, carried out using detectors to measure the
radiation emitted
Note 1 to entry: Normally, the measurement devices are whole-body or partial-body (e.g. lung, thyroid) counters.
3.17
monitoring
measurements made for the purpose of assessment or control of exposure to radioactive material and
the interpretation of the results
Note 1 to entry: This International Standard distinguishes five different categories of monitoring programmes,
namely, routine monitoring programme (3.18), task-related monitoring programme (3.19), triage monitoring
programme (3.20), special monitoring programme (3.21), and confirmatory monitoring programme (3.22).
Note 2 to entry: This International Standard distinguishes two different types of monitoring, namely, individual
monitoring (3.23) and workplace monitoring (3.24).
3.18
routine monitoring programme
monitoring programme associated with continuing operations and intended to demonstrate that
working conditions, including the levels of individual dose, remain satisfactory, and to meet regulatory
requirements
3.19
task-related monitoring programme
monitoring programme related to a specific operation, to provide information on a specific operation of
limited duration, or following major modifications applied to the installations or operating procedures,
or to confirm that the routine monitoring programme (3.18) is suitable
3.20
triage monitoring programme
monitoring programme consist of frequent measurements performed in the nuclear medicine centres
that does not enable one to calculate a dose but to verify that a given threshold of potential intake (3.14)
is not surpassed
3.21
special monitoring programme
monitoring programme performed to quantify significant exposures following actual or suspected
abnormal events
3.22
confirmatory monitoring programme
monitoring programme carried out to confirm assumptions about working conditions, for example,
that significant intakes (3.14) have not occurred
3.23
individual monitoring
monitoring by means of equipment worn by individual workers, by measurement of the quantities
of radioactive materials in or on the bodies of individual workers, or by measurement of radioactive
material excreted by individual workers
3.24
workplace monitoring
monitoring using measurements made in the working environment
3.25
monitoring interval
period between two consecutive times of measurement
4 © ISO 2016 – All rights reserved

ISO 16637:2016(E)
3.26
quality assurance
planned and systematic actions necessary to provide adequate confidence that a process, measurement,
or service satisfy given requirements for quality such as those specified in a licence
3.27
quality control
part of quality assurance (3.26) intended to verify that systems and components correspond to
predetermined requirements
3.28
quality management
all activities of the overall management function that determine the quality policy, objectives, and
responsibilities and that implement them by means such as quality planning, quality control (3.27),
quality assurance (3.26), and quality improvement within the quality system
3.29
reference level
investigation level (3.30) or recording level (3.29)
3.30
recording level
level of dose, exposure, or intake (3.14) specified by the employer or the regulatory authority, at or
above which values of dose received by workers are to be entered in their individual records
3.31
investigation level
level of dose, exposure, or intake (3.14) at or above which investigation has to be made in order to reduce
the uncertainty associated with the dose assessment
3.32
retention function
function describing the fraction of an intake (3.14) present in the body or in a tissue, organ, or region of
the body after a given time has elapsed since the intake occurred
3.33
scattering factor
geometric standard deviation of the lognormal distribution of bioassay measurements
3.34
time of measurement
time at which the measurement begins
4 Symbols and abbreviated terms
A Value of the activity detection limit (in becquerel) for routine measurements
DL
AMAD Activity median aerodynamic diameter
3 -1
B Breathing rate of worker (m ·h )
-3
C Airborne concentration of radionuclide (Bq·m )
m
DL Detection limit
E(50) Committed effective dose accumulated for an integration period of 50 years following an unit intake (Sv)
e(50) Dose coefficient i.e. committed effective dose accumulated for an integration period of 50 years follow-
-1
ing a unit intake (Sv·Bq )
m(t) Predicted value of the measured quantity at time, t, for unit intake (excretion or retention function at
time t for unit intake)
I Intake (Bq)
IAEA International Atomic Energy Agency
ISO 16637:2016(E)
ICRP International Commission on Radiological Protection
ΔT Duration of the monitoring interval between two measurements in a routine monitoring programme
(in days)
T Time spent by the worker in the radioactive atmosphere (h)
work
5 Purpose and need for monitoring programmes in nuclear medical diagnosis
and therapy
5.1 General
The purpose of monitoring, in general, is to verify and document that the worker is protected adequately
against risks from radionuclide intakes and the protection complies with legal requirements. Therefore,
it forms part of the overall radiation protection programme, which should start with an assessment to
identify work situations in which there is a risk of radionuclide intake by workers, and to quantify the
annual likely intake of radioactive material and the resulting committed effective dose. Decisions about
the need for monitoring and the design of the monitoring programme should be made in the light of
such a risk assessment.
5.2 Assessment of the level of likely exposures
It is necessary to assess the likely magnitude of exposures without taking into account personal
protective measures. If available, this assessment can be done on the basis of results of earlier
monitoring programmes (individual or workplace monitoring) and/or on measurements performed at
the workplace to characterize the radiological conditions.
In nuclear medicine, workers can be contaminated by inhalation of volatile compounds (mainly
radioiodine) or aerosols. As a result, individual monitoring for internal contamination may be necessary
[1]
for those workers who regularly work with large activities of volatile radioactive materials.
In order to assess the level of likely exposures, quantification of airborne contamination should be
performed in departments where I-131 is used in large amount, i.e. for therapy or where aerosols are
used for pulmonary inhalation examination.
To assess the risk of I-131 inhalation, air sampling should be performed in areas where there is a
potential for airborne radioactivity. These areas may include the following:
— hot laboratory;
— radioiodine treatment rooms and adjacent areas;
— facility radioactive waste and effluent storage areas.
For a specific radionuclide, the likely committed effective dose due to airborne radioactivity for a
worker can be calculated by
Ie× ()50
E 50 = (1)
()
0,001
where
E(50) is the committed effective dose for the radionuclide (mSv);
I is the intake for the radionuclide (Bq);
-1
e(50) is the dose coefficient (Sv·Bq ) for inhalation of the radionuclide and;
0,001 is a conversion factor from Sv to mSv.
6 © ISO 2016 – All rights reserved

ISO 16637:2016(E)
[2]
Values for e(50) shall be taken from ICRP 68 or, for radiopharmaceuticals used as aerosols, from
[3]
ICRP 53 and following addenda. For iodine radioactive isotopes, a vapour form should be assumed
unless material-specific information suggesting a particulate form is available.
The likely intake can be calculated by
IB=×TC× (2)
work m
where
3 -1
B is the mean breathing rate of a sedentary worker (1,2 m ·h );
T is the time spent by the worker in the radioactive atmosphere (h) and;
work
-3
C is the airborne concentration of the radionuclide (Bq·m ).
m
If no other reliable information is available or may be obtained from workplace and/or individual
[4]
measurements, the criteria suggested by IAEA Safety Guide RS-G-1.2 and presented in Annex A,
can be used to determine whether an internal monitoring program is needed for nuclear medicine
[5][6][7]
workers .
5.3 Monitoring programmes
5.3.1 General
Factors determining the need for a monitoring programme are the following:
— the magnitude of likely exposures;
— the need to recognize incorporation events;
— the need to assess the effectiveness of protective equipment.
A monitoring programme can include individual and/or workplace monitoring. These two types of
monitoring provide different information.
— Individual monitoring gives information needed to assess the exposure of a single worker by
measuring individual body activities, excretion rates, or activity inhaled (using personal air
samplers).
— Workplace monitoring, either by air monitoring or by measurements of the surface contamination,
helps to assess the potential for internal exposure of workers through inhalation and provides
information on the risk of contamination for setting up individual monitoring programmes for
workers. It complements individual monitoring, since it provides useful indicators for predicting
doses and for establishing protective measures for the operation.
As stated in ISO 20553, a monitoring programme for internal contamination is required if the worker is
occupationally exposed and the assessed dose contribution from intakes of radionuclides is likely to be
significant and is recommended if the level of the likely annual committed effective dose exceeds 1 mSv.
For workers exposed to medical radionuclides as unsealed sources in nuclear medicine departments,
different categories of monitoring programmes can be implemented depending on the risk assessment:
confirmatory monitoring programmes, triage monitoring programmes, routine or task-related
monitoring programmes, and special monitoring programmes, following an incidental intake.
5.3.2 Confirmatory monitoring programmes
Confirmatory monitoring, which consists of workplace and/or individual monitoring performed
occasionally or at regular intervals, should be required to check the assumptions about exposure
conditions underlying the procedures selected, e.g. the effectiveness of protection measures. Recorded
data should be periodically reviewed as they can demonstrate the need for triage, routine, or task-
ISO 16637:2016(E)
related monitoring. The time of implementation should be during the process identified as the highest
risk of internal exposure.
Confirmatory monitoring is not intended to quantify doses. However, it can be used to review the risk
of contamination and the estimation of the likely dose and, following this review, it can demonstrate
the need to implement a routine or triage monitoring programme.
5.3.3 Routine monitoring programmes
Routine monitoring programmes are performed to quantify exposures where there is the possibility
either of undetected accidental intakes or of chronic intakes. The basis for routine monitoring
programmes is the assumption that working conditions, and thus risks of intake, remain reasonably
constant. The design of such a programme of regular measurements strongly depends on the level of
the annual dose the quantification of which is ensured. This level should be well below legally relevant
limits; its definition should take into account uncertainties, for example, in activity measurement and
dose assessment. If this level is too high, intakes representing considerable fractions of dose limits could
be overlooked, whilst a low value can cause the expenditure of unnecessary efforts at low exposures.
5.3.4 Triage monitoring programmes
Triage monitoring programmes rely on frequent individual screening measurements performed at the
workplace by local staff using standard laboratory instrumentation to detect whether potential intake
has occurred. Screening measurements, in contrast with in vivo or in vitro measurement performed in
the frame of a routine monitoring programme, do not enable the calculation of an accurate or precise
absorbed dose but can be used to determine whether a dose threshold is exceeded. If the screening
threshold is exceeded, in vivo or in vitro radiobioassays are performed in order to confirm internal
contamination and to quantify the incorporated activity for dose assessment.
5.3.5 Task-related monitoring programmes
Task-related monitoring programmes apply to a specific operation. The purpose and the dose criteria
for carrying out task-related monitoring programmes are identical to those for routine monitoring
programmes.
In nuclear medicine, task-related monitoring programmes are required in the case of a new diagnostic
or therapeutic protocol and operations of limited duration to provide data for dose assessment and for
the radiation protection optimisation process. This is also necessary after major modifications have
been applied to the installations or operating procedures. The general requirements set out in 8.1 for
routine monitoring programmes shall be applied to task-related monitoring programmes. In contrast
to routine monitoring programmes, more information can be available about the circumstances of an
intake event, especially relating to the time between measurement and the intake.
The objectives of a task-related monitoring programme and the way it is organized, including the basis
for interpreting the results, shall be documented.
5.3.6 Special monitoring programmes
Special monitoring programmes are performed to quantify significant exposures following actual
or suspected abnormal events (by example, the spill of a radiopharmaceutical solution) or in case
of a positive screening during triage monitoring. Therefore, in comparison to routine monitoring
programmes, the time of intake is usually much better known, and additional information can be
available, which helps to reduce the uncertainty of assessment. The purposes of dose assessment in such
cases include assisting in decisions about countermeasures (e.g. decorporation therapy), compliance
with legal regulations, and aiding decisions for the improvement of conditions at the workplace. In
most cases, special monitoring programmes are performed individually. In cases where there is reason
to suspect that the annual effective dose limit could be exceeded, it can be appropriate to extend the
measurements in order to derive individual-specific retention and excretion functions and biokinetic
model parameters.
8 © ISO 2016 – All rights reserved

ISO 16637:2016(E)
5.3.7 Implementation of a monitoring programme
A detailed flowchart is proposed as Figure 1 to contribute to the implementation of monitoring
programmes. This flowchart presents the monitoring programmes to apply following three starting
points corresponding to different situations:
1) the commissioning of a new nuclear medicine facility or the review of an existing facility;
2) the development of a new protocol (by example for a new radiopharmaceutical);
3) the suspicion of an incidental contamination.
Periodic review of the monitoring programmes shall be conducted, taking into account the recorded
data (internal contamination measurements results and, when performed, assessed doses).
Figure 1 — Flowchart for the implementation of monitoring programmes
ISO 16637:2016(E)
6 Common radionuclides
Most of the radionuclides used in nuclear medicine have short half-lives (Table 1). For diagnostic use,
the emitted energy shall be deposited in the gamma camera scintillator, with minimal absorption by
the tissue. On the contrary, for therapeutic use, the energy shall be deposited in the tissue. Therefore,
radionuclides with γ or β+ decay are used for imaging and radionuclides with α or β- decays are used
for therapeutic purposes.
Table 1 — Most commonly used radionuclides in nuclear medicine
a
Radionuclides Half-li
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