SIST EN IEC 61674:2024

SLOVENSKI STANDARD
01-oktober-2024
Medicinska električna oprema - Dozimetri z ionizacijskimi komorami in/ali
polprevodniški detektorji, kot se uporabljajo pri rentgenskem diagnostičnem
slikanju (IEC 61674:2024)
Medical electrical equipment - Dosimeters with ionization chambers and/or
semiconductor detectors as used in X-ray diagnostic imaging (IEC 61674:2024)
Medizinische elektrische Geräte - Dosimeter mit Ionisationskammern und/oder
Halbleiterdetektoren für den Einsatz an diagnostischen Röntgeneinrichtungen (IEC
61674:2024)
Appareils électromédicaux - Dosimètres à chambres d’ionisation et/ou à détecteurs
semiconducteurs utilisés en imagerie de diagnostic à rayonnement X (IEC 61674:2024)
Ta slovenski standard je istoveten z: EN IEC 61674:2024
ICS:
11.040.50 Radiografska oprema Radiographic equipment
17.240 Merjenje sevanja Radiation measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61674

NORME EUROPÉENNE
EUROPÄISCHE NORM August 2024
ICS 11.040.50 Supersedes EN 61674:2013
English Version
Medical electrical equipment - Dosimeters with ionization
chambers and/or semiconductor detectors as used in X-ray
diagnostic imaging
(IEC 61674:2024)
Appareils électromédicaux - Dosimètres à chambres Medizinische elektrische Geräte - Dosimeter mit
d'ionisation et/ou à détecteurs semiconducteurs utilisés en Ionisationskammern und/oder Halbleiterdetektoren für den
imagerie de diagnostic à rayonnement X Einsatz an diagnostischen Röntgeneinrichtungen
(IEC 61674:2024) (IEC 61674:2024)
This European Standard was approved by CENELEC on 2024-08-13. CENELEC 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 CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61674:2024 E
European foreword
The text of document 62C/909/FDIS, future edition 3 of IEC 61674, prepared by SC 62C "Equipment
for radiotherapy, nuclear medicine and radiation dosimetry" of IEC/TC 62 "Medical equipment,
software, and systems" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC
as EN IEC 61674:2024.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-05-13
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-08-13
document have to be withdrawn
This document supersedes EN 61674:2013 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61674:2024 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60601-1:2005 NOTE Approved as EN 60601-1:2006 (not modified) +A11:2011
IEC 60601-1:2005/A1:2012 NOTE Approved as EN 60601-1:2006/A1:2013 (not modified)
IEC 60601-1:2005/A2:2020 NOTE Approved as EN 60601-1:2006/A2:2021 (not modified)
IEC 60601-1-3:2008 NOTE Approved as EN 60601-1-3:2008 (not modified) +A11:2016
IEC 60601-1-3:2008/A1:2013 NOTE Approved as EN 60601-1-3:2008/A1:2013 (not modified)
IEC 60601-1-3:2008/A2:2021 NOTE Approved as EN 60601-1-3:2008/A2:2021 (not modified)
IEC 60731:2011 NOTE Approved as EN 60731:2012 (not modified)
IEC 61010-1 NOTE Approved as EN 61010-1
IEC 61676:2023 NOTE Approved as EN IEC 61676:2023 (not modified)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60417 - Graphical symbols for use on equipment - -
IEC/TR 60788 2004 Medical electrical equipment - Glossary of - -
defined terms
IEC 61000-4 series Electromagnetic compatibility (EMC) - Part EN IEC 61000-4 series
4: Testing and measurement techniques
IEC 61000-4-2 2008 Electromagnetic compatibility (EMC) - Part EN 61000-4-2 2009
4-2: Testing and measurement techniques
- Electrostatic discharge immunity test
IEC 61000-4-3 2020 Electromagnetic compatibility (EMC) - Part EN IEC 61000-4-3 2020
4-3 : Testing and measurement techniques
- Radiated, radio-frequency,
electromagnetic field immunity test
IEC 61000-4-4 - Electromagnetic compatibility (EMC) - Part EN 61000-4-4 -
4-4: Testing and measurement techniques
- Electrical fast transient/burst immunity
test
IEC 61000-4-6 - Electromagnetic compatibility (EMC) - Part EN IEC 61000-4-6 -
4-6: Testing and measurement techniques
- Immunity to conducted disturbances,
induced by radio-frequency fields
IEC 61000-4-11 - Electromagnetic compatibility (EMC) - Part EN IEC 61000-4-11 -
4-11: Testing and measurement
techniques - Voltage dips, short
interruptions and voltage variations
immunity tests for equipment with input
current up to 16 A per phase
IEC 61187 - Electrical and electronic measuring EN 61187 -
equipment - Documentation
IEC 61267 2005 Medical diagnostic X-ray equipment - EN 61267 2006
Radiation conditions for use in the
determination of characteristics

IEC 61674 ®
Edition 3.0 2024-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Medical electrical equipment – Dosimeters with ionization chambers and/or
semiconductor detectors as used in X-ray diagnostic imaging
Appareils électromédicaux – Dosimètres à chambres d'ionisation et/ou à
détecteurs semiconducteurs utilisés en imagerie de diagnostic à rayonnement X
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 11.040.50 ISBN 978-2-8322-8971-6
– 2 – IEC 61674:2024 © IEC 2024
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope and object . 7
1.1 Scope . 7
1.2 Object . 7
2 Normative references . 7
3 Terms and definitions . 8
4 General requirements . 16
4.1 Performance requirements . 16
4.2 REFERENCE VALUES and STANDARD TEST VALUES . 16
4.3 General test conditions . 17
4.3.1 STANDARD TEST CONDITIONS . 17
4.3.2 Statistical fluctuations . 17
4.3.3 STABILIZATION TIME . 17
4.3.4 Adjustments during test . 18
4.3.5 Batteries . 18
4.4 Constructional requirements as related to performance . 18
4.4.1 Components . 18
4.4.2 Display . 18
4.4.3 Indication of battery condition . 18
4.4.4 Indication of polarizing voltage failure . 18
4.4.5 Over-ranging . 19
4.4.6 MEASURING ASSEMBLIES with multiple DETECTOR ASSEMBLIES . 19
4.4.7 Radioactive STABILITY CHECK DEVICE . 20
4.5 UNCERTAINTY of measurement . 20
5 Limits of PERFORMANCE CHARACTERISTICS . 20
5.1 Linearity . 20
5.2 Repeatability . 20
5.2.1 General . 20
5.2.2 Repeatability in the ATTENUATED BEAM . 21
5.2.3 Repeatability in the UNATTENUATED BEAM . 21
5.3 RESOLUTION of reading . 22
5.4 STABILIZATION TIME . 22
5.5 Effect of pulsed radiation on AIR KERMA and AIR KERMA LENGTH PRODUCT
measurements . 22
5.6 Stability. 22
5.6.1 Long term stability . 22
5.6.2 Accumulated dose stability . 23
5.7 Measurements with a radioactive STABILITY CHECK DEVICE . 23
6 LIMITS OF VARIATION for effects of INFLUENCE QUANTITIES . 23
6.1 General . 23
6.2 Energy dependence of RESPONSE . 23
6.3 AIR KERMA RATE dependence of AIR KERMA and AIR KERMA LENGTH PRODUCT
measurements . 25
6.4 Dependence of DETECTOR RESPONSE on angle of incidence of radiation . 25
6.4.1 Non-CT detectors . 25
6.4.2 CT DETECTORS . 26

IEC 61674:2024 © IEC 2024 – 3 –
6.5 Operating voltage . 26
6.5.1 Mains-operated DOSIMETERS . 26
6.5.2 Battery-operated DOSIMETERS . 26
6.5.3 Mains rechargeable, battery-operated DOSIMETERS . 26
6.6 Air pressure . 27
6.7 Air pressure EQUILIBRATION TIME of the RADIATION DETECTOR . 27
6.8 Temperature and humidity . 27
6.9 Electromagnetic compatibility . 28
6.9.1 ELECTROSTATIC DISCHARGE . 28
6.9.2 Radiated electromagnetic fields . 28
6.9.3 CONDUCTED DISTURBANCES induced by bursts and radio frequencies . 29
6.9.4 Voltage dips, short interruptions and voltage VARIATIONS . 29
6.10 Field size . 29
6.11 EFFECTIVE LENGTH and spatial uniformity of RESPONSE of CT DOSIMETERS . 29
7 Marking . 30
7.1 DETECTOR ASSEMBLY . 30
7.2 MEASURING ASSEMBLY . 30
7.3 Radioactive STABILITY CHECK DEVICE . 30
8 ACCOMPANYING DOCUMENTS . 30
Annex A (informative) COMBINED STANDARD UNCERTAINTY for dosimeter performance . 32
Bibliography . 33
Index of defined terms . 34

Table 1 – REFERENCE and STANDARD TEST CONDITIONS . 16
Table 2 – Number of readings required to detect true differences ∆ (95 % confidence
level) between two sets of instrument readings . 17
Table 3 – Maximum values for the COEFFICIENT OF VARIATION, v , for measurements
max
in the attenuated beam . 21
Table 4 – Maximum values for the COEFFICIENT OF VARIATION, v , for measurements
max
in the unattenuated beam and mammography . 21
Table 5 – LIMITS OF VARIATION for the effects of INFLUENCE QUANTITIES . 24
Table 6 – Climatic conditions . 27
Table A.1 – Estimation of COMBINED STANDARD UNCERTAINTY for dosimeter performance . 32

– 4 – IEC 61674:2024 © IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEDICAL ELECTRICAL EQUIPMENT –
DOSIMETERS WITH IONIZATION CHAMBERS AND/OR SEMICONDUCTOR
DETECTORS AS USED IN X-RAY DIAGNOSTIC IMAGING

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 61674 has been prepared by subcommittee 62C: Equipment for radiotherapy, nuclear
medicine and radiation dosimetry, of IEC technical committee 62: Medical equipment, software,
and systems. It is an International Standard.
This third edition cancels and replaces the second edition published in 2012. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) for mammography, the manufacturer specifies the REFERENCE VALUE for the RADIATION
QUALITY;
b) for mammography, the manufacturer provides the MINIMUM RATED RANGE of RADIATION
QUALITIES for the compliance test on energy dependence of response;
c) the compliance test for analogue displays was removed;

IEC 61674:2024 © IEC 2024 – 5 –
d) the compliance tests for range reset, the effect of leakage and recombination losses were
removed. These tests are already covered by the test on linearity and cannot be conducted
for modern devices. The estimation of COMBINED STANDARD UNCERTAINTY was changed
accordingly;
e) the compliance test for mains rechargeable and battery-operated dosimeters were updated
for modern devices.
The text of this International Standard is based on the following documents:
Draft Report on voting
62C/909/FDIS 62C/913/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
In this document, the following print types are used.
– requirements and definitions: roman type.
– test specifications: italic type.
– informative material appearing outside of tables, such as notes, examples and references: in smaller type.
Normative text of tables is also in a smaller type.
– TERMS DEFINED IN CLAUSE 3 OF IEC 60601-1:2005, IEC 60601-1:2005/AMD1:2012 AND
IEC 60601-1:2005/AMD2:2020, IN THIS PARTICULAR STANDARD OR AS NOTED: SMALL CAPITALS.
The verbal forms used in this document conform to usage described in Clause 7 of the ISO/IEC
Directives, Part 2:2021. For the purposes of this document, the auxiliary verb:
– "shall" means that compliance with a requirement or a test is mandatory for compliance with
this document;
– "should" means that compliance with a requirement or a test is recommended but is not
mandatory for compliance with this document;
– "may" is used to describe a permissible way to achieve compliance with a requirement or
test.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
– 6 – IEC 61674:2024 © IEC 2024
INTRODUCTION
Diagnostic radiology is the largest contributor to man-made IONIZING RADIATION to which the
public is exposed. The reduction in the exposure received by PATIENTS undergoing medical
radiological examinations or procedures has therefore become a central issue in recent years.
The PATIENT dose will be minimized when the X-ray producing equipment is correctly adjusted
for image quality and radiation output. These adjustments require that the routine measurement
of AIR KERMA, AIR KERMA LENGTH PRODUCT and/or AIR KERMA RATE be made accurately. The
equipment covered by this document plays an essential part in achieving the required accuracy.
It is important that the DOSIMETERS used for adjustment and control measurements are of
satisfactory quality and therefore fulfil the special requirements laid down in this document.

IEC 61674:2024 © IEC 2024 – 7 –
MEDICAL ELECTRICAL EQUIPMENT –
DOSIMETERS WITH IONIZATION CHAMBERS AND/OR SEMICONDUCTOR
DETECTORS AS USED IN X-RAY DIAGNOSTIC IMAGING

1 Scope and object
1.1 Scope
This document specifies the performance and some related constructional requirements of
DIAGNOSTIC DOSIMETERS intended for the measurement of AIR KERMA, AIR KERMA LENGTH PRODUCT
or AIR KERMA RATE, in photon radiation fields used in medical X-ray imaging, such as
RADIOGRAPHY, RADIOSCOPY and COMPUTED TOMOGRAPHY (CT), for X-RADIATION with generating
potentials in the range of 20 kV to 150 kV.
This document is applicable to the performance of DOSIMETERS with VENTED IONIZATION
CHAMBERS and/or SEMICONDUCTOR DETECTORS as used in X-ray diagnostic imaging.
1.2 Object
The object of this document is
a) to establish requirements for a satisfactory level of performance for DIAGNOSTIC DOSIMETERS,
and
b) to standardize the methods for the determination of compliance with this level of
performance.
DOSIMETERS. The DIAGNOSTIC
This document is not concerned with the safety aspects of
DOSIMETERS covered by this document are not intended for use in the PATIENT ENVIRONMENT
and, therefore, the requirements for electrical safety applying to them are contained in
IEC 61010-1.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60417, Graphical symbols for use on equipment, available at http://www.graphical-
symbols.info/equipment
IEC TR 60788:2004, Medical electrical equipment – Glossary of defined terms
IEC 61000-4 (all parts), Electromagnetic compatibility (EMC) – Part 4: Testing and measuring
techniques
IEC 61000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test
IEC 61000-4-3:2020, Electromagnetic compatibility (EMC) – Part 4-3: Testing and
measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4, Electromagnetic compatibility (EMC) – Part 4-4: Testing and measurement
techniques – Electrical fast transient/burst immunity test

– 8 – IEC 61674:2024 © IEC 2024
IEC 61000-4-6, Electromagnetic compatibility (EMC) – Part 4-6: Testing and measurement
techniques – Immunity to conducted disturbances, induced by radio-frequency fields
IEC 61000-4-11, Electromagnetic compatibility (EMC) – Part 4-11: Testing and measurement
techniques – Voltage dips, short interruptions and voltage variations immunity tests for
equipment with input current up to 16 A per phase
IEC 61187, Electrical and electronic measuring equipment – Documentation
IEC 61267:2005, Medical diagnostic X-ray equipment – Radiation conditions for use in the
determination of characteristics
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TR 60788:2004 and
the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1
DIAGNOSTIC DOSIMETER
DOSIMETER
equipment which uses IONIZATION CHAMBERS and/or SEMICONDUCTOR DETECTORS for the
measurement of AIR KERMA, AIR KERMA LENGTH PRODUCT and/or AIR KERMA RATE in the beam of
an X-RAY EQUIPMENT used for diagnostic medical radiological examinations
Note 1 to entry: A DIAGNOSTIC DOSIMETER contains the following components:
– one or more DETECTOR ASSEMBLIES which may or may not be an integral part of the MEASURING ASSEMBLY;
– a MEASURING ASSEMBLY;
– one or more STABILITY CHECK DEVICES (optional).
3.1.1
DETECTOR ASSEMBLY
RADIATION DETECTOR and all other parts to which the RADIATION DETECTOR is permanently
attached, except the MEASURING ASSEMBLY
Note 1 to entry: The DETECTOR ASSEMBLY normally includes:
– the RADIATION DETECTOR and the stem (or body) on which the RADIATION DETECTOR is permanently mounted (or
embedded);
– the electrical fitting and any permanently attached cable or pre-amplifier.
3.1.1.1
RADIATION DETECTOR
element which transduces AIR KERMA, AIR KERMA LENGTH PRODUCT or AIR KERMA RATE into a
measurable electrical signal
Note 1 to entry: A radiation detector may be either an ionization chamber or a semiconductor detector.

IEC 61674:2024 © IEC 2024 – 9 –
3.1.1.1.1
IONIZATION CHAMBER
CHAMBER
RADIATION DETECTOR filled with air, a suitable gas, or a gaseous mixture, in which an electric
field is provided for the total collection, at the electrodes, of charges associated with the ions
and the electrons produced in the sensitive volume of the detector by the ionizing radiation
Note 1 to entry: An ionization chamber can be sealed or vented.
Note 2 to entry: Vented ionization chambers are constructed in such a way as to allow the air inside the measuring
volume to communicate freely with the atmosphere, so that corrections to the response for changes in air density
need to be made.
Note 3 to entry: Sealed ionization chambers are not suitable, because the necessary wall thickness of a sealed
chamber may cause an unacceptable energy dependence of the response and because the long-term stability of
sealed chambers is not guaranteed.
[SOURCE: IEC 60050-395:2014, 395-03-07, modified – Two new notes to entry were added.]
3.1.1.1.2
VENTED IONIZATION CHAMBER
IONIZATION CHAMBER constructed in such a way as to allow the air inside the measuring volume
to communicate freely with the atmosphere such that corrections to the RESPONSE for changes
in air density need to be made
[SOURCE: IEC 60731:2011, 3.1.1.1.3, modified – The term has been changed from "vented
chamber" to "VENTED IONIZATION CHAMBER".]
3.1.1.1.3
SEMICONDUCTOR DETECTOR
semiconductor device that utilises the production and motion of electron-hole pairs in a charge
carrier depleted region of the semiconductor for the detection and measurement of IONIZING
RADIATION
Note 1 to entry: The production of electron-hole pairs is caused by interaction of the IONIZING RADIATION with the
semiconductor material. In the purview of this document, detectors qualify as semiconductor detectors, even when
the production of electron-hole pairs is caused indirectly by first converting the incident radiation energy to light in a
scintillator material directly in front of and optically coupled to a semiconductor photodiode, which then produces the
electrical signal.
3.1.2
MEASURING ASSEMBLY
device to measure the electrical signal from the RADIATION DETECTOR and convert it into a form
suitable for displaying the values of DOSE or KERMA or their corresponding rates
[SOURCE: IEC 60731:2011, 3.1.2, modified – The words "measure the charge (or current) from
the IONIZATION CHAMBER" have been replaced with "measure the electrical signal from the
RADIATION DETECTOR".]
3.1.3
STABILITY CHECK DEVICE
device which enables the stability of RESPONSE of the MEASURING ASSEMBLY and/or CHAMBER
ASSEMBLY to be checked
Note 1 to entry: The STABILITY CHECK DEVICE may be a purely electrical device, or a radiation source, or it may
include both.
[SOURCE: IEC 60731:2011, 3.1.3]

– 10 – IEC 61674:2024 © IEC 2024
3.1.4
CT DOSIMETER
DIAGNOSTIC DOSIMETER which uses long narrow IONIZATION CHAMBERS and/or SEMICONDUCTOR
DETECTORS for the measurement of AIR KERMA integrated along the length of the DETECTOR when
the DETECTOR is exposed to a cross-sectional X-ray scan of a computed tomograph
Note 1 to entry: A CT DOSIMETER contains the following components:
– one or more DETECTOR ASSEMBLIES;
– a MEASURING ASSEMBLY.
3.1.5
CT DETECTOR
RADIATION DETECTOR which is used for CT dosimetry
3.2
INDICATED VALUE
value of a quantity derived from the reading of an instrument together with any scale factors
indicated on the control panel of the instrument
[SOURCE: IEC 60731:2011, 3.2, modified – The note has been deleted.]
3.3
TRUE VALUE
value of the physical quantity to be measured by an instrument
[SOURCE: IEC 60731:2011, 3.3, modified – The note has been deleted.]
3.4
CONVENTIONAL TRUE VALUE
value used instead of the TRUE VALUE when calibrating or determining the performance of an
instrument, since in practice the TRUE VALUE is unknown and unknowable
Note 1 to entry: The CONVENTIONAL TRUE VALUE will usually be the value determined by the WORKING STANDARD with
which the instrument under test is being compared.
[SOURCE: IEC 60731:2011, 3.4, modified – The second note has been deleted.]
3.5
MEASURED VALUE
best estimate of the TRUE VALUE of a quantity, being derived from the INDICATED VALUE of an
CORRECTION FACTORS and the
instrument together with the application of all relevant
CALIBRATION FACTOR
Note 1 to entry: The MEASURED VALUE is sometimes also referred to as "result of a measurement".
[SOURCE: IEC 60731:2011, 3.5, modified – The existing note has been replaced with a new
note to entry.]
3.5.1
ERROR OF MEASUREMENT
difference remaining between the MEASURED VALUE of a quantity and the TRUE VALUE of that
quantity
[SOURCE: IEC 60731:2011, 3.5.1]

IEC 61674:2024 © IEC 2024 – 11 –
3.5.2
OVERALL UNCERTAINTY
UNCERTAINTY associated with the MEASURED VALUE
Note 1 to entry: I.e. it represents the bounds within which the ERROR OF MEASUREMENT is estimated to lie (see also
4.5).
[SOURCE: IEC 60731:2011, 3.5.2, modified – The parenthesis has been added to the note to
entry, and the second note has been deleted.]
3.5.3
EXPANDED UNCERTAINTY
quantity defining an interval about the result of a measurement that may be expected to
encompass a large fraction of the distribution of values that could reasonably be attributed to
the measurand
[SOURCE: ISO/IEC GUIDE 98-3:2008, 2.3.5, modified – The three notes have been deleted.]
3.6
CORRECTION FACTOR
dimensionless multiplier which corrects the INDICATED VALUE of an instrument from its value
when operated under particular conditions to its value when operated under stated REFERENCE
CONDITIONS
[SOURCE: IEC 60731:2011, 3.6]
3.7
INFLUENCE QUANTITY
external quantity that may affect the performance of an instrument
[SOURCE: IEC 60731:2011, 3.7]
3.8
INSTRUMENT PARAMETER
internal property of an instrument that may affect the performance of this instrument
[SOURCE: IEC 60731:2011, 3.8]
3.9
REFERENCE VALUE
particular value of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER chosen for the purposes
of reference
Note 1 to entry: i.e., the value of an influence quantity (or INSTRUMENT PARAMETER) at which the CORRECTION FACTOR
for dependence on that INFLUENCE QUANTITY (or INSTRUMENT PARAMETER) is unity.
[SOURCE: IEC 60731:2011, 3.9]
3.9.1
REFERENCE CONDITIONS
conditions under which all INFLUENCE QUANTITIES and INSTRUMENT PARAMETERS have their
REFERENCE VALUES
[SOURCE: IEC 60731:2011, 3.9.1]

– 12 – IEC 61674:2024 © IEC 2024
3.10
STANDARD TEST VALUES
value, values, or range of values of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER, which
are permitted when carrying out calibrations or tests on another INFLUENCE QUANTITY or
INSTRUMENT PARAMETER
[SOURCE: IEC 60731:2011, 3.10]
3.10.1
STANDARD TEST CONDITIONS
conditions under which all INFLUENCE QUANTITIES and INSTRUMENT PARAMETERS have their
STANDARD TEST VALUES
[SOURCE: IEC 60731:2011, 3.10.1]
3.11
PERFORMANCE CHARACTERISTIC
one of the quantities used to define the performance of an instrument
[SOURCE: IEC 60731:2011, 3.11, modified – The note has been deleted.]
3.11.1
RESPONSE
quotient of the INDICATED VALUE divided by the
CONVENTIONAL TRUE VALUE at the position of the REFERENCE POINT of the RADIATION DETECTOR
[SOURCE: IEC 60731:2011, 3.11.1, modified – Only the first paragraph has been retained.]
3.11.2
RESOLUTION
smallest change of reading to which a numerical value can be assigned without
further interpolation
[SOURCE: IEC 60731:2011, 3.11.2, modified – Only the first paragraph has been retained.]
3.11.2.1
RESOLUTION
smallest significant increment of the reading
[SOURCE: IEC 60731:2011, 3.11.2, modified – Only the third paragraph has been retained.]
3.11.3
EQUILIBRATION TIME
time taken for a reading to reach and remain within a specified deviation from its final steady
value after a sudden change in an INFLUENCE QUANTITY has been applied to the instrument
[SOURCE: IEC 60731:2011, 3.11.3]
3.11.4
RESPONSE TIME
time taken for a reading to reach and remain within a specified deviation from its final steady
value after a sudden change in the quantity being measured
[SOURCE: IEC 60731:2011, 3.11.4]

IEC 61674:2024 © IEC 2024 – 13 –
3.11.5
STABILIZATION TIME
time taken for a stated PERFORMANCE CHARACTERISTIC to reach and remain within a specified
deviation from its final steady value after the MEASURING ASSEMBLY has been switched on and
the polarizing voltage has been applied to the IONIZATION CHAMBER
[SOURCE: IEC 60731:2011, 3.11.5]
3.11.6
CHAMBER ASSEMBLY LEAKAGE CURRENT
LEAKAGE CURRENT
current in the signal path arising in the CHAMBER ASSEMBLY which is not produced by ionization
in the measuring volume
[SOURCE: IEC 60731:2011, 3.11.6, modified – The note has been deleted.]
3.12
VARIATION
relative difference, ∆y/y, between the values of a PERFORMANCE CHARACTERISTIC y, when one
INFLUENCE QUANTITY (or INSTRUMENT PARAMETER) assumes successively two specified values,
the other INFLUENCE QUANTITIES (and INSTRUMENT PARAMETERS) being kept constant at the
STANDARD TEST VALUES (unless other values are specified)
[SOURCE: IEC 60731:2011, 3.12]
3.13
LIMITS OF VARIATION
maximum permitted VARIATION of a PERFORMANCE CHARACTERISTIC
Note 1 to entry: If LIMITS OF VARIATION are stated as ±L %, the VARIATION ∆y/y, expressed as a percentage, shall
remain in the range from – L % to + L %.
[SOURCE: IEC 60731:2011, 3.13]
3.14
EFFECTIVE RANGE OF INDICATED VALUES
EFFECTIVE RANGE
range of INDICATED VALUES for which an instrument complies with a stated performance
Note 1 to entry: The maximum (minimum) effective INDICATED VALUE is the highest (lowest) in this range.
Note 2 to entry: The concept of EFFECTIVE RANGE may, for example, also be applied to readings and to related
quantities not directly indicated by the instrument e.g., input current.
[SOURCE: IEC 60731:2011, 3.14]
3.15
RATED RANGE OF USE
RATED RANGE
range of values of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER within which the instrument
will operate within the LIMITS OF VARIATION
Note 1 to entry: Its limits are the maximum and minimum RATED VALUES.
[SOURCE: IEC 60731:2011, 3.15]

– 14 – IEC 61674:2024 © IEC 2024
3.15.1
MINIMUM RATED RANGE
least range of an INFLUENCE QUANTITY or INSTRUMENT PARAMETER over which the instrument shall
operate within the specified LIMITS OF VARIATION
[SOURCE: IEC 60731:2011, 3.15.1]
3.16
REFERENCE POINT OF A RADIATION DETECTOR
REFERENCE POINT
point of a RADIATION DETECTOR which, during the calibration of the detector, is brought to
coincidence with the point at which the CONVENTIONAL TRUE VALUE is specified
[SOURCE: IEC 60731:2011, 3.16, modified – The term "IONIZATION CHAMBER" has been replaced
RADIATION DETECTOR" in both the term and the definition.]
with "
3.17
MEDICAL ELECTRICAL EQUIPMENT
ME EQUIPMENT
electrical equipment having an APPLIED PART or transferring energy to or from the PATIENT or
detecting such energy transfer to or from the PATIENT and which is:
a) provided with not more than one connection to a particular SUPPLY MAINS; and
b) intended by its manufacturer to be used:
1) in the diagnosis, treatment, or monitoring of a PATIENT; or
2) for compensation or alleviation of disease, injury or disability
[SOURCE: IEC 60601-1:2005, 3.63, modified – The five notes have not been retained.]
3.18
UNATTENUATED BEAM
X-ray beam incident on the PATIENT or PHANTOM
3.18.1
UNATTENUATED BEAM QUALITY
RADIATION QUALITY of the X-ray beam at the location of the entrance surface of the PATIENT or
the PHANTOM, determined when the latter are absent
3.19
ATTENUATED BEAM
X-ray beam exiting the PATIENT or PHANTOM
3.19.1
ATTENUATED BEAM QUALITY
RADIATION QUALITY of the X-ray beam exiting the PATIENT or PHANTOM
3.20
RATED LENGTH
length along the axis of the CT DETECTOR within which the DETECTOR performs to its specification
3.20.1
EFFECTIVE LENGTH
length along the axis of the CT DETECTOR between the two points at which the RESPONSE has
fallen to 50 % of its value at its geometrical centre

IEC 61674:2024 © IEC 2024 – 15 –
3.21
AIR KERMA
K
quotient of dE by dm where dE is the sum of the initial kinetic energies of all the charged
tr tr
ionizing particles liberated by uncharged ionizing particles in air of mass dm
–1
Note 1 to entry: The unit of AIR KERMA is Gy (where 1 Gy = 1 J·kg ).
[SOURCE: IEC 60731:2011, 3.31, modified – The second note has been deleted.]
3.21.1
AIR KERMA RATE

K
quotient of dK by dt, where dK is the increment of AIR KERMA in the time interval dt
–1 –1 –1
Note 1 to entry: The unit of AIR KERMA RATE is Gy·s (Gy·min ; Gy·h ).
[SOURCE: IEC 60731:2011, 3.31.1, modified – The second note has been deleted.]
3.21.2
AIR KERMA LENGTH PRODUCT
P
KL
line integral of the AIR KERMA K over a length L

P = K(z)dz
KL
∫
(1)
L
Note 1 to entry: The unit of AIR KERMA LENGTH PRODUCT is Gy·m (mGy·m).
3.22
X-RAY TUBE VOLTAGE
potential difference applied to an X-RAY TUBE between the ANODE and the CATHODE
Note 1 to entry: The unit of this quantity is the volt (V).
Note 2 to entry: The X-RAY TUBE VOLTAGE may vary as a function of time. The PRACTICAL PEAK VOLTAGE is a weighted
value
...